Patent Publication Number: US-2016236348-A1

Title: Robot, carriage device, and control method using inertia sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation patent application of U.S. patent application Ser. No. 14/174,255 filed Feb. 6, 2014, which is a continuation of U.S. application Ser. No. 13/890,572 filed May 9, 2013, now U.S. Pat. No. 8,849,456 issued Sep. 30, 2014, which is a continuation of U.S. application Ser. No. 12/814,908 filed Jun. 14, 2010, now U.S. Pat. No. 8,463,440 issued Jun. 11, 2013, which claims priority to Japanese Patent Application No. 2009-141943, filed Jun. 15, 2009, all of which are expressly incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a robot capable of moving a terminal device, which is attached to a front end of an arm, to a wanted position, a carriage device capable of moving the terminal device, which is attached to the movable member, to a wanted position, and a control method using an inertia sensor to control these devices. 
     2. Related Art 
     In the past, it has been widely known an apparatus such as a robot capable of moving a terminal device, which is attached to a front end of an arm by pivoting the arm and so on, to a wanted position and operating the terminal device at the position. For example, there are known a feeding/releasing material device having a gripping terminal and feeding and releasing a matching target part to and from a machining apparatus, an applicator robot having an applicator terminal, a welding robot having a welding terminal or the like. 
     When the robot is driven, a control method is used, in which a pivot angle of a driving source such as a motor for driving a robot arm is measured, a position of a front end of the arm or the like is controlled based on information on the measured angle. However, since a transmission mechanism for transmitting a driving force to the arm from the driving source or the arm is not made of a rigid body, the transmission mechanism or the arm is deformed. As a result, there is a case in which the position of the front end side of the arm, of which the position is controlled based on the angle information, does not necessarily coincide with an actual position. In addition, there is a problem in that vibration is generated since the transmission mechanism or the arm is deformed upon the operation. In order to solve the problem, a method is devised in which an inertia sensor is attached to the front end of the arm to measure the movement of the front end and thus control the angular velocity information obtained by the inertia sensor. JP-A-7-9374 discloses a control method for an articulated robot and an articulated robot capable of determining a position with high precision in a case in which rigidity is low and preventing the precision from being deteriorated due to vibration, by controlling operation of the arm using an output signal of the inertia sensor. 
     However, in order to obtain a pivot angle of an arm from the output of the inertia sensor, it is necessary to integrate the output of the inertia sensor. In addition, there is a problem in that if the integration is repeated, it is liable to receive an effect of a drift of a reference potential of the inertia sensor, so that a control device is capable of highly misrecognizing the information. In JP-A-2005-242794, a robot control device and a robot control method are disclosed to preclude an error factor which is varied in a low frequency, such as a drift of the reference potential, by using a low frequency component from an output of an angle sensor, in which an output of an angular velocity sensor is used to control a high frequency component only which is an integral value of the output. 
     However, there is a problem in that an error due to the effect of the noise, the effect in delay of signal transmission or the like is possibly contained in the output of the inertia sensor, and thus the control device easily misrecognizes the information due to the error. Since the effect from the noise of the inertia sensor or the effect from the delay of the signal transmission is a phenomenon which happens even in a high frequency, the control device or the control method disclosed in JP-A-2005-242794 cannot cope with the problem. 
     SUMMARY 
     The invention has been made to solve at least a part of the problems, and may be implemented as the following embodiments or application example. 
     APPLICATION EXAMPLE 1 
     A robot according to this application example includes an arm with one end pivotally supported; a driving source that pivots the arm; an angle sensor that detects a pivot angle of the driving source and outputs pivot angle information of the driving source; an inertia sensor that is attached to the arm and outputs angular velocity information of the arm by detecting the angular velocity of the arm rotation; a control command generating unit that outputs a control command defining rotational operation of the arm; a control conversion determining unit that determines whether the angular velocity information is used or not when the driving source is controlled to control operation of the arm; and an arm operation control unit that performs a first control based on the control command, the pivot angle information, and the angular velocity information, to control the driving source and thus control the operation of the arm, if the control conversion determining unit determines to use the angular velocity information, and performs a second control which is different from the first control, based on the control command and the pivot angle information, to control the driving source and thus control the operation of the arm, if the control conversion determining unit determines not to use the angular velocity information. 
     In the robot according to this application example, the control conversion determining unit determines whether the angular velocity information is used or not when controlling the operation of the arm. The arm operation control unit performs the first control based on the control command, the pivot angle information, and the angular velocity information, and performs a second control based on the control command and the pivot angle information, in accordance with the determination of the control conversion determining unit. Therefore, in order to perform the appropriate control, the control in which the angular velocity information is appropriately used or is not used can be selected, in cases in which the effect obtained by using the angular velocity information is high and is low, or in cases in which the error of the angular velocity information is relatively high and is relatively low. In addition, the control method which is effective by using the angular velocity information can be selected and performed. 
     The first control is a control method of suppressing vibration or the like by using the control command, the pivot angle information and the angular velocity information, and is called, for example, a state feedback control. The second control is a control method of rendering it to approach a wanted position stably by using the control command and the pivot angle information, and is, for example, a PID (Proportional Integral Differential) control based on the angle of the angle sensor or the angular velocity of its differential value, or the like. 
     APPLICATION EXAMPLE 2 
     A robot according to this application example includes an arm with one end pivotally supported; a driving source that pivots the arm; an angle sensor that detects a pivot angle of the driving source and outputs pivot angle information of the driving source; an inertia sensor that is attached to the arm and outputs angular velocity information of the arm by detecting the angular velocity of the arm rotation; a control command generating unit that outputs a control command defining rotational operation of the arm; a control conversion determining unit that determines a weighted constant of the angular velocity information when the driving source is controlled to control operation of the arm; and an arm operation control unit that controls the driving source and thus controls the operation of the arm based on the control command, the pivot angle information, and the angular velocity information which is multiplied by the weighted constant determined by the control conversion determining unit. 
     In the robot according to this application example, the control conversion determining unit determines the weighted constant of the angular velocity information, and the arm operation control unit controls the operation of the arm based on the control command, the pivot angle information, and the angular velocity information which is multiplied by the weighted constant determined by the control conversion determining unit. As a result, when the appropriate control is performed, since the weighted constant is determined by comprehensively considering the influence obtained by using the angular velocity information and the influence resulted from the error of the angular velocity information, the operation control of the arm can be performed which increases the effect obtained by using the angular velocity information and reduces the influence resulted from the error of the angular velocity information overall. 
     APPLICATION EXAMPLE 3 
     In the robot according to this application example, it is preferable that a threshold value is previously set in the angular velocity information, and the control conversion determining unit compares the angular velocity information with the threshold value to determine whether the angular velocity information is used or not, or to determine the weighted constant of the angular velocity information. 
     According to the robot of this application example, by comparing the angular velocity information with the threshold value, it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined. More appropriate control can be performed by using the angular velocity information, as compared with the case in which the angular velocity information is not used. However, if the angular velocity is reduced, the effect obtained by using the angular velocity information is decreased, and simultaneously, the influence resulted from the error of the angular velocity information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the angle information is used. Since it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined, by comparing the angular velocity information with the threshold value, the operation control of the arm can be performed which increases the effect obtained by using the angular velocity information and reduces the influence resulted from the error of the angular velocity information overall. 
     APPLICATION EXAMPLE 4 
     In the robot according to this application example, it is preferable that a threshold value is previously set in the pivot angle information, and the control conversion determining unit compares the pivot angle information with the threshold value to determine whether the angular velocity information is used or not, or to determine the weighted constant of the angular velocity information. 
     According to the robot of this application example, by comparing the pivot angle information with the threshold value, it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined. More appropriate control can be performed by using the angular velocity information, as compared with the case in which the angular velocity information is not used. However, in a state in which the pivot angle is increased and thus approaches the wanted angle, the angular velocity is reduced. If the angular velocity is reduced, the effect obtained by using the angular velocity information is decreased, and simultaneously, the influence resulted from the error of the angular velocity information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the angle information is used. Since it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined, by comparing the angular velocity information with the threshold value, the operation control of the arm can be performed which increases the effect obtained by using the angular velocity information and reduces the influence resulted from the error of the angular velocity information overall. 
     APPLICATION EXAMPLE 5 
     In the robot according to this application example, it is preferable that a threshold value is previously set in an integral value of one or more times of the angular velocity information, and the control conversion determining unit compares the integral value of one or more times of the angular velocity information with the threshold value to determine whether the angular velocity information is used or not, or to determine the weighted constant of the angular velocity information. 
     According to the robot of this application example, by comparing the integral value of one or more times of the angular velocity information with the threshold value, it is determined whether the angular velocity information is used or the weighted constant of the angular velocity information is determined. More appropriate control can be performed by using the angular velocity information, as compared with the case in which the angular velocity information is not used. If the angular velocity is reduced, the effect obtained by using the angular velocity information is decreased, and simultaneously, the influence resulted from the error of the angular velocity information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the angle information is used. Since it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined, by comparing the integral value of one or more times of the angular velocity information with the threshold value, the operation control of the arm can be performed which increases the effect obtained by using the angular velocity information and reduces the influence resulted from the error of the angular velocity information overall. The comparison of the integral value of one or more times of the angular velocity information with the threshold value can take the same determination criteria as the case of comparing the angular velocity information with the threshold value. It can easily treat the unit with the pivot angle information or the like in common by treating the integral value of one or more times of the angular velocity information. 
     APPLICATION EXAMPLE 6 
     In the robot according to this application example, it is preferable that a threshold value is previously set in a differential value of one or more times of the pivot angle information, and the control conversion determining unit compares the differential value of one or more times of the pivot angle information with the threshold value to determine whether the angular velocity information is used or not, or to determine the weighted constant of the angular velocity information. 
     According to the robot of this application example, by comparing the differential value of one or more times of the pivot angle information with the threshold value, it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined. More appropriate control can be performed by using the angular velocity information, as compared with the case in which the angular velocity information is not used. However, in a state in which the pivot angle is increased and thus approaches the wanted angle, the angular velocity is reduced. If the angular velocity is reduced, the effect obtained by using the angular velocity information is decreased, and simultaneously, the influence resulted from the error of the angular velocity information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the angle information is used. Since it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined, by comparing the differential value of one or more times of the angular velocity information with the threshold value, the operation control of the arm can be performed which increases the effect obtained by using the angular velocity information and reduces the influence resulted from the error of the angular velocity information overall. The comparison of the differential value of one or more times of the angular velocity information with the threshold value can take the same determination criteria as the case of comparing the pivot angle information with the threshold value. It can easily treat the unit with the angular velocity information or the like in common by treating the differential value of one or more times of the pivot angle information. 
     APPLICATION EXAMPLE 7 
     In the robot according to this application example, it is preferable that a threshold value is previously set in a time axis based on a specific point of the control command, and the control conversion determining unit compares a lapse time from the specific point with the threshold value to determine whether the angular velocity information is used or not, or to determine the weighted constant of the angular velocity information. 
     According to the robot of this application example, by comparing the lapse time from the specific point of the control command with the threshold value, it is determined whether the angular velocity information is used or not, or the weighted constant of the angular velocity information is determined. More appropriate control can be performed by using the angular velocity information, as compared with the case in which the angular velocity information is not used. If the angular velocity is reduced, the effect obtained by using the angular velocity information is decreased, and simultaneously, the influence resulted from the error of the angular velocity information by the noise or the like is increased. Since it is determined whether the angular velocity information is used or not or the weighted constant of the angular velocity information is determined, by comparing the lapse time from the specific point of the control command with the threshold value, the operation control of the arm can be performed which increases the effect obtained by using the angular velocity information and reduces the influence resulted from the error of the angular velocity information overall. 
     For example, if a predetermined time or more passes from a specific point of the control command, such as the wanted moving position, the value of the angular velocity information becomes a value of the angular velocity at the specific point defined by the control command. By comparing the lapse time from the specific point of the control command with the threshold value, it can be as the same determination criteria as the case in which the angular velocity information is compared with the threshold value. The control can be easily performed by setting the lapse time as the criteria, as compared with the case in which the angular velocity information or the like is compared with the threshold value. 
     APPLICATION EXAMPLE 8 
     In the robot according to this application example, it is preferable that a threshold value is previously set in a noise affecting the angular velocity information, and the control conversion determining unit compares the noise affecting the angular velocity information with the threshold value to determine whether the angular velocity information is used or not or to determine the weighted constant of the angular velocity information. 
     According to the robot of this application example, by comparing the noise affecting the angular velocity information with the threshold value, it is determined whether the angular velocity information is used or not or the weighted constant of the angular velocity information is determined. More appropriate control can be performed by using the angular velocity information, as compared with the case in which the angular velocity information is not used. If the noise affecting the angular velocity information is increased, the influence of the error in the angular velocity information due to the noise or the like is increased, and thus the effect obtained by using the angular velocity information is decreased. Since it is determined whether the angular velocity information is used or not or the weighted constant of the angular velocity information is determined, by comparing the noise affecting the angular velocity information with the threshold value, the operation control of the arm can be performed which reduces the influence resulted from the error of the angular velocity information. 
     APPLICATION EXAMPLE 9 
     A carriage device according to this application example includes a slidably supported movable unit; a driving source that moves the movable unit; a position sensor that detects a driving amount of the driving source and outputs position information of the driving source; an inertia sensor that is attached to the movable unit and outputs acceleration information of an acceleration acting on the movable unit when the movable unit is moved; a control command generating unit that outputs a control command defining movement operation of the movable unit; a control conversion determining unit that determines whether the acceleration information is used or not when the driving source is controlled to control the movement operation of the movable unit; and an operation control unit that performs a first control based on the control command, the position information, and the acceleration information, to control the driving source and thus control the movement operation of the movable unit, if the control conversion determining unit determines to use the acceleration information, and performs a second control which is different from the first control, based on the control command and the position information, to control the driving source and thus control the movement operation of the movable unit, if the control conversion determining unit determines not to use the angular velocity information. 
     According to the carriage device of this application example, the control conversion determining unit determines whether the acceleration information is used or not when controlling the operation of the movable unit. The operation control unit performs the first control based on the control command, the position information, and the acceleration information, and performs a second control based on the control command and the position information, in accordance with the determination of the control conversion determining unit. Therefore, in order to perform the appropriate control, the control in which the acceleration information is appropriately used or is not used can be selected, in cases in which the effect obtained by using the acceleration information is high and is low, or in cases in which the error of the acceleration information is relatively high and is relatively low. In addition, the control method which is effective by using the acceleration information can be selected and performed. 
     The first control is a control method of suppressing vibration or the like by using the control command, the position information and the acceleration information, and is called, for example, a state feedback control. The second control is a control method of rendering it to approach a wanted position stably by using the control command and the position information, and is, for example, a PID (Proportional Integral Differential) control based on the angle of the angle sensor or the angular velocity of its differential value, or the like. 
     APPLICATION EXAMPLE 10 
     A carriage device according to this application example includes a slidably supported movable unit; a driving source that moves the movable unit; a position sensor that detects a driving amount of the driving source and outputs position information of the driving source; an inertia sensor that is attached to the movable unit and outputs acceleration information of an acceleration acting on the movable unit when the movable unit is moved; a control command generating unit that outputs a control command defining movement operation of the movable unit; a control conversion determining unit that determines a weighted constant of the acceleration information when the driving source is controlled to control the movement operation of the movable unit; and an operation control unit that controls the driving source and thus controls the operation of the movable unit based on the control command, the position information, and the acceleration information which is multiplied by the weighted constant determined by the control conversion determining unit. 
     In the carriage device according to this application example, the control conversion determining unit determines the weighted constant of the acceleration information, and the operation control unit controls the movement operation of the movable unit based on the control command, the position information, and the acceleration information which is multiplied by the weighted constant determined by the control conversion determining unit. As a result, when the appropriate control is performed, since the weighted constant is determined by comprehensively considering the effect obtained by using the acceleration information and the influence resulted from the error of the acceleration information, the operation control of the movable unit can be performed which increases the effect obtained by using the acceleration information and reduces the influence resulted from the error of the acceleration information overall. 
     APPLICATION EXAMPLE 11 
     According to the carriage device of this application example, it is preferable that a threshold value is previously set in the acceleration information, and the control conversion determining unit compares the acceleration information with the threshold value to determine whether the acceleration information is used or not, or to determine the weighted constant of the acceleration information. 
     According to the carriage device of this application example, by comparing the acceleration information with the threshold value, it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined. More appropriate control can be performed by using the acceleration information, as compared with the case in which the acceleration information is not used. However, if the acceleration is reduced, the effect obtained by using the acceleration information is decreased, and simultaneously, the influence resulted from the error of the acceleration information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined, by comparing the acceleration information with the threshold value, the operation control of the movable unit can be performed which increases the effect obtained by using the acceleration information and reduces the influence resulted from the error of the acceleration information overall. 
     APPLICATION EXAMPLE 12 
     According to the carriage device of this application example, it is preferable that a threshold value is previously set in the position information, and the control conversion determining unit compares the position information with the threshold value to determine whether the acceleration information is used or not or to determine the weighted constant of the acceleration information. 
     According to the carriage device of this application example, by comparing the position information with the threshold value, it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined. More appropriate control can be performed by using the acceleration information, as compared with the case in which the acceleration information is not used. However, in a state in which it moves at a constant velocity at a position as the moving amount is increased than a constant amount or a state in which it approaches the wanted position and then the moving velocity is decreased, the acceleration is reduced. If the acceleration is reduced, the effect obtained by using the acceleration is decreased, and simultaneously, the influence resulted from the error of the acceleration information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined, by comparing the position information with the threshold value, the operation control of the movable unit can be performed which increases the effect obtained by using the acceleration information and reduces the influence resulted from the error of the acceleration information overall. 
     APPLICATION EXAMPLE 13 
     According to the carriage device of this application example, it is preferable that a threshold value is previously set in an integral value of one or more times of the acceleration information, and the control conversion determining unit compares the integral value of one or more times of the acceleration information with the threshold value to determine whether the acceleration information is used or not, or to determine the weighted constant of the acceleration information. 
     According to the carriage device of this application example, by comparing the integral value of one or more times of the acceleration information with the threshold value, it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined. More appropriate control can be performed by using the acceleration information, as compared with the case in which the acceleration information is not used. If the acceleration is reduced, the effect obtained by using the acceleration information is decreased, and simultaneously, the influence resulted from the error of the acceleration information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the acceleration information is used or the weighted constant of the acceleration information is determined, by comparing the integral value of one or more times of the acceleration information with the threshold value, the operation control of the movable unit can be performed which increases the effect obtained by using the acceleration information and reduces the influence resulted from the error of the acceleration information overall. The comparison of the integral value of one or more times of the acceleration information with the threshold value can take the same determination criteria as the case of comparing the acceleration information with the threshold value. It can easily treat the unit with the position information or the like in common by treating the integral value of one or more times of the acceleration information. 
     APPLICATION EXAMPLE 14 
     According to the carriage device of this application example, it is preferable that a threshold value is previously set in a differential value of one or more times of the position information, and the control conversion determining unit compares the differential value of one or more times of the position information with the threshold value to determine whether the acceleration information is used or not or to determine the weighted constant of the acceleration information. 
     According to the carriage device of this application example, by comparing the differential value of one or more times of the position information with the threshold value, it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined. More appropriate control can be performed by using the acceleration information, as compared with the case in which the acceleration information is not used. However, in a state in which it moves at a constant velocity at a position as the moving amount is increased than a constant amount or a state in which it approaches the wanted position and then the moving velocity is decreased, the acceleration is reduced. If the acceleration is reduced, the effect obtained by using the acceleration information is decreased, and simultaneously, the influence resulted from the error of the acceleration information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined, by comparing the differential value of one or more times of the position information with the threshold value, the operation of the movable unit can be performed which increases the effect obtained by using the acceleration information and reduces the influence resulted from the error of the acceleration information overall. The comparison of the differential value of one or more times of the position information with the threshold value can take the same determination criteria as the case of comparing the position information with the threshold value. It can easily treat the unit with the acceleration information or the like in common by treating the differential value of one or more times of the position information. 
     APPLICATION EXAMPLE 15 
     According to the carriage device of this application example, it is preferable that a threshold value is previously set in a time axis based on a specific point of the control command, and the control conversion determining unit compares a lapse time from the specific point with the threshold value to determine whether the acceleration information is used or not, or to determine the weighted constant of the acceleration information. 
     According to the carriage device of this application example, by comparing the lapse time on the specific time of the control command with the threshold value, it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined. More appropriate control can be performed by using the acceleration information, as compared with the case in which the acceleration information is not used. However, if the acceleration is reduced, the effect obtained by using the acceleration information is decreased, and simultaneously, the influence resulted from the error of the acceleration information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined, by comparing the lapse time from the specific point of the control command with the threshold value, the moving operation of the movable unit can be controlled which increases the effect obtained by using the acceleration information and reduces the influence resulted from the error of the acceleration information overall. 
     For example, if a predetermined time or more passes from a specific point of the control command, such as the wanted position, the value of the acceleration information becomes a value of the acceleration at the specific point defined by the control command. By comparing the lapse time from the specific point of the control command with the threshold value, it can be as the same determination criteria as the case where the acceleration information is compared with the threshold value. The control can be easily performed by setting the lapse time as the criteria, as compared with the case in which the acceleration information or the like is compared with the threshold value. 
     APPLICATION EXAMPLE 16 
     According to the carriage device of this application example, it is preferable that a threshold value is previously set in a noise affecting the acceleration information, and the control conversion determining unit compares the noise affecting the acceleration information with the threshold value to determine whether the acceleration information is used or not, or to determine the weighted constant of the acceleration information. 
     According to the carriage device of this application example, by comparing the noise affecting the acceleration information with the threshold value, it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined. More appropriate control can be performed by using the acceleration information, as compared with the case in which the acceleration information is not used. However, if the noise affecting the acceleration information is increased, the influence of the error in the acceleration information due to the noise or the like is increased, and thus the effect obtained by using the acceleration information is decreased. Since it is determined whether the acceleration information is used or not, or the weighted constant of the acceleration information is determined, by comparing the noise affecting the acceleration information with the threshold value, the moving operation of the movable unit can be controlled which reduces the influence resulted from the error of the acceleration information. 
     APPLICATION EXAMPLE 17 
     A control method using an inertia sensor according to this application example, in which a pivotally or slidably supported movable unit or a driving source that pivots or slides the movable unit is controlled by using an output of the inertia sensor which is disposed at the movable unit, includes the steps of: outputting a control command defining movement operation of the movable unit; detecting position information of the driving source; detecting inertial force information acting on the movable unit by the inertia sensor when the movable unit is moved; determining a control conversion of determining whether the inertial force information is used or not, when the driving source is controlled to control movement operation of the movable unit; and if the use of the inertial force information is determined in the step of determining the control conversion, performing a first control based on the position information, and the inertial force information to control the movement operation of the movable unit through controlling the driving source according to the control command, and if the non-use of the inertial force information is determined in the step of determining the control conversion, performing a second control which is different from the first control, based on the position information, to control the driving source according to the control command and thus control the movement operation of the movable unit. 
     In the control method according to this application example, in the step of determining the control conversion, the control conversion determining unit determines whether the inertial force information is used or not, or not when controlling the moving operation of the movable unit. In the drive control step, the first control is performed based on the control command, the position information, and the inertial force information, and a second control is performed based on the control command and the position information, in accordance with the determination of the step of determining the control conversion. Therefore, in order to perform the appropriate control, the control in which the inertial force information is appropriately used or is not used can be selected, in cases in which the effect obtained by using the inertial force information is high and is low, or in cases in which the error of the inertial force information is relatively high and is relatively low. In addition, the control method which is effective by using the inertial force information can be selected and performed. 
     The first control is a control method of suppressing vibration or the like by using the control command, the position information and the inertial force information, and is called, for example, a state feedback control. The second control is a control method of rendering it to approach a wanted position stably by using the control command and the position information, and is, for example, a PID (Proportional Integral Differential) control based on the angle of the angle sensor or the angular velocity of its differential value, or the like. 
     APPLICATION EXAMPLE 18 
     A control method using an inertia sensor according to this application example, in which a pivotally or slidably supported movable unit or a driving source that pivots or slides the movable unit is controlled by using an output of the inertia sensor which is disposed at the movable unit, includes the steps of: outputting a control command defining movement operation of the movable unit; detecting a driving amount of the driving source and detecting position information of the driving source; detecting inertial force information acting on the movable unit by the inertia sensor when the movable unit is moved; determining a weighted constant of the inertial force information, when the driving source is controlled by using the inertial force information to control movement operation of the movable unit; and controlling the movement operation of the movable unit by controlling the driving source using the control command, the position information, and the inertial force information which is multiplied by the weighted constant determined in the step of determining the weighted constant. 
     In the control method according to this application example, in the step of determining the constant, the weighted constant of the inertial force information is determined, and in the driving control step, the moving operation of the movable unit is controlled based on the control command, the position information, and the inertial force information which is multiplied by the weighted constant determined by the control conversion determining unit. As a result, when the appropriate control is performed, since the weighted constant is determined by comprehensively considering the influence obtained by using the inertial force information and the influence resulted from the error of the inertial force information, the moving operation of the movable unit can be performed which increases the effect obtained by using the inertial force information and reduces the influence resulted from the error of the inertial force information overall. 
     APPLICATION EXAMPLE 19 
     According to the control method of this application example, it is preferable that the step of determining the control conversion or the step of determining the weighted constant is a step of determining whether the inertial force information is used or not, or determining the weighted constant of the inertial force information by comparing the inertial force information with a threshold value which is previously set with respect to the inertial force information. 
     According to the control method using the inertial force of this application example, in the step of determining the control conversion or the step of determining the weighted constant, by comparing the inertial force information with the threshold value, it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined. More appropriate control can be performed by using the inertial force information, as compared with the case in which the inertial force information is not used. However, if the inertial force is reduced, the effect obtained by using the inertial force information is decreased, and simultaneously, the influence resulted from the error of the inertial force information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined, by comparing the inertial force information with the threshold value, the operation of the movable unit can be performed which increases the effect obtained by using the inertial force information and reduces the influence resulted from the error of the inertial force information overall. 
     APPLICATION EXAMPLE 20 
     According to the control method using the inertial force of this application example, it is preferable that the step of determining the control conversion or the step of determining the weighted constant is a step of determining whether the inertial force information is used or not, or determining the weighted constant of the inertial force information by comparing the position information with a threshold value which is previously set with respect to the position information. 
     According to the control method by using the inertial force of this application example, by comparing the position information with the threshold value, it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined. More appropriate control can be performed by using the inertial force information, as compared with the case in which the inertial force information is not used. However, in a state in which it moves at a constant velocity at a position as the moving amount is increased than a constant amount or a state in which it approaches the wanted position and then the moving velocity is decreased, the inertial force is reduced. If the inertial force is reduced, the effect obtained by using the inertial force information is decreased, and simultaneously, the influence resulted from the error of the inertial force information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined, by comparing the position information with the threshold value, the moving operation of the movable unit can be controlled which increases the effect obtained by using the inertial force information and reduces the influence resulted from the error of the inertial force information overall. 
     APPLICATION EXAMPLE 21 
     According to the control method using the inertial force of this application example, it is preferable that the step of determining the control conversion or the step of determining the weighted constant is a step of determining whether the inertial force information is used or not, or determining the weighted constant of the inertial force information by comparing an integral value of one or more times of the inertial force information with a threshold value which is previously set with respect to the integral value of one or more times of the inertial force information. 
     According to the control method using the inertial force of this application example, in the step of determining the control conversion or determining the weighted constant, by comparing the integral value of one or more times of the inertial force information with the threshold value, it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined. More appropriate control can be performed by using the inertial force information, as compared with the case in which the inertial force information is not used. However, if the inertial force is reduced, the effect obtained by using the inertial force information is decreased, and simultaneously, the influence resulted from the error of the inertial force information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined, by comparing the integral value of one or more times of the inertial force information with the threshold value, the moving operation of the movable unit can be controlled which increases the effect obtained by using the inertial force information and reduces the influence resulted from the error of the inertial force information overall. The comparison of the integral value of one or more times of the inertial force information with the threshold value can take the same determination criteria as the case of comparing the inertial force information with the threshold value. It can easily treat the unit with the position information or the like in common by treating the integral value of one or more times of the inertial force information. 
     APPLICATION EXAMPLE 22 
     According to the control method using the inertial force of this application example, it is preferable that the step of determining the control conversion or the step of determining the weighted constant is a step of determining whether the inertial force information is used or not, or determining the weighted constant of the inertial force information by comparing a differential value of one or more times of the position information with a threshold value which is previously set with respect to the differential value of one or more times of the position information. 
     According to the control method using the inertial force of this application example, in the step of determining the control conversion, by comparing the differential value of one or more times of the position information with the threshold value, it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined. More appropriate control can be performed by using the inertial force information, as compared with the case in which the inertial force information is not used. However, in a state in which it moves at a constant velocity at a position as the moving amount is increased than a constant amount or a state in which it approaches the wanted position and then the moving velocity is decreased, the inertial force is reduced. If the inertial force is reduced, the effect obtained by using the inertial force information is decreased, and simultaneously, the influence resulted from the error of the inertial force information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined, by comparing the differential value of one or more times of the position information with the threshold value, the moving operation of the movable unit can be controlled which increases the effect obtained by using the inertial force information and reduces the influence resulted from the error of the inertial force information overall. The comparison of the differential value of one or more times of the inertial force information with the threshold value can take the same determination criteria as the case of comparing the position information with the threshold value. It can easily treat the unit with the inertial force information or the like in common by treating the differential value of one or more times of the position information. 
     APPLICATION EXAMPLE 23 
     According to the control method using the inertial force of this application example, it is preferable that the step of determining the control conversion or the step of determining the weighted constant is a step of determining whether the inertial force information is used or not, or determining the weighted constant of the inertial force information by comparing a lapse time from a specific point of the control command with the threshold value which is previously set in a time axis based on the specific point of the control command. 
     According to the control method using the inertial force of this application example, by comparing a lapse time from a specific point of the control command with the threshold value, it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined. More appropriate control can be performed by using the inertial force information, as compared with the case in which the inertial force information is not used. However, if the inertial force is reduced, the effect obtained by using the inertial force information is decreased, and simultaneously, the influence resulted from the error of the inertial force information by the noise or the like is obtained. Therefore, the precision is lowered as compared with the case in which only the position information is used. Since it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined, by comparing the lapse time from the specific point of the control command with the threshold value, the moving operation of the movable unit can be controlled which increases the effect obtained by using the inertial force information and reduces the influence resulted from the error of the inertial force information overall. 
     For example, if a predetermined time or more passes from a specific point of the control command, such as the wanted moving position, the value of the inertial force information becomes a value of the inertial force at the specific point defined by the control command. By comparing the lapse time from the specific point of the control command with the threshold value, it can be as the same determination criteria as the case in which the inertial force information is compared with the threshold value. The control can be easily performed by setting the lapse time as the criteria, as compared with the case in which the inertial force information or the like is compared with the threshold value. 
     APPLICATION EXAMPLE 24 
     According to the control method using the inertial force of this application example, it is preferable that the step of determining the control conversion or the step of determining the weighted constant is a step of determining whether the inertial force information is used or not, or determining the weighted constant of the inertial force information by comparing a noise affecting the inertial force information with the threshold value which is previously set in the noise affecting the inertial force information. 
     According to the control method using the inertial force of this application example, in the step of determining the control conversion or the step of determining the weighed constant, it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined by comparing the noise affecting the inertial force information with the threshold value. More appropriate control can be performed by using the inertial force information, as compared with the case in which the inertial force information is not used. However, if the noise affecting the inertial force information is increased, the influence of the error in the inertial force information due to the noise or the like is increased, and thus the effect obtained by using the inertial force information is decreased. Since it is determined whether the inertial force information is used or not, or the weighted constant of the inertial force information is determined, by comparing the noise affecting the inertial force information with the threshold value, the moving operation of the movable unit can be controlled which reduces the influence resulted from the error of the inertial force information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a perspective view schematically illustrating the external configuration of a feeding/releasing material device. 
         FIG. 2  is a block diagram illustrating a functional configuration of driving a robot mechanism. 
         FIG. 3  is a flowchart illustrating a process of pivoting a feeding/releasing material arm by controlling a drive of an arm driving motor. 
         FIG. 4A  is a diagram illustrating an example of a relationship between a time lapse and an angular velocity, and a threshold value of the angular velocity while a feeding/releasing material arm is pivoted. 
         FIG. 4B  is a diagram illustrating an example of a relationship between a time lapse and an angular velocity, and a threshold value of the angular velocity while a feeding/releasing material arm is stopped. 
         FIG. 5  is a block diagram illustrating a functional configuration of driving a robot mechanism. 
         FIG. 6  is a flowchart illustrating a process of pivoting a feeding/releasing material arm by controlling a drive of an arm driving motor. 
         FIG. 7A  is a diagram illustrating an example of a relationship between a time lapse and an angular velocity, and a threshold value of the angular velocity while a feeding/releasing material arm is pivoted. 
         FIG. 7B  is a diagram illustrating an example of angular velocity information. 
         FIG. 8A  is a diagram illustrating an example of a relationship between a time lapse and a pivot angle, and a threshold value of the pivot angle while a feeding/releasing material arm is pivoted. 
         FIG. 8B  is a diagram illustrating an example of a relationship between a time lapse and an angle, and a threshold value of the angle while a feeding/releasing material arm is stopped. 
         FIG. 9A  is a diagram illustrating an example of a relationship between time lapse and an angular velocity, and a threshold value defined on a time axis with respect to a wanted stop position which is a specific point of a control command value while a feeding/releasing material arm is pivoted. 
         FIG. 9B  is a diagram illustrating an example of a relationship between a time lapse and an angular velocity in the vicinity of a wanted stop position which is a specific point of a control command value, and a threshold value defined on a time axis with respect to the wanted stop position which is the specific point of the control command. 
         FIG. 10  is a perspective view schematically illustrating the external configuration of a feeding/releasing material device. 
         FIGS. 11A and 11B  are perspective views schematically illustrating the external configuration of a carriage device. 
         FIG. 12  is a diagram schematically illustrating a major part of a laser printer. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Next, one example of a robot, a carriage device and a control method using an inertia sensor will be described with reference to the drawings. In the drawings referred in the following description, there is a case in which a vertical or horizontal scale of a member or portion or a scale for every portion is represented differently from a real scale in order to easily understand a constituent member. 
     Embodiment 1 
     A first embodiment of a robot, a carriage device and a control method using an inertia sensor will now be described. In this embodiment, a feeding/releasing material device which is an example of the carriage device will be described by way of an example. For example, in a process of fabricating a semiconductor device, the feeding/releasing material device of the embodiment is a feeding/releasing material device capable of treating a wafer on which a plurality of semiconductor chips constituting a semiconductor device is compartment-formed. 
     Feeding/Releasing Material Device 
     First, the mechanical configuration of a feeding/releasing material device  10  will be described with reference to  FIG. 1 .  FIG. 1  is a perspective view schematically illustrating an external configuration of the feeding/releasing material device. 
     As shown in  FIG. 1 , the feeding/releasing material device  10  includes a holding hand  12 , a robot mechanism  20 , a feeding/releasing material device control unit  30 , an angular velocity sensor  32 , and an angle sensor  34  (refer to  FIG. 2 ). 
     The robot mechanism  20  includes a hand holding mechanism  24 , a feeding/releasing material arm  21 , an arm shaft part  26 , and a base  28 . The base  28  supports the arm shaft part  26  in such a way that the arm shaft part can be rotated around a rotational shaft of the arm shaft part  26  via a built-in bearing mechanism (not illustrated) and can be precisely positioned. The arm shaft part  26  is connected to the arm driving motor  22  (refer to  FIG. 2 ) built in the base  28  via an arm driving mechanism  23  (refer to  FIG. 2 ), and thus is pivoted by the arm driving motor  22 . The arm driving motor  22  is connected to the angle sensor  34 , and a pivot angle of the arm driving motor  22  is measured by the angle sensor  34 . 
     An end portion of the arm shaft part  26  which is opposite to its end portion supported by the base  28  is fixed to one end portion of the feeding/releasing material arm  21 . The feeding/releasing material arm  21  is pivoted around the rotational shaft of the arm shaft part  26  by the arm driving motor  22 . The pivot angle of the feeding/releasing material arm  21  is approximately measured by measuring the pivot angle of the arm driving motor  22  using the angle sensor  34 . 
     The hand holding mechanism  24  is fixed to the end portion of the arm shaft part  26  which is opposite to its end portion supported by the base  28 . The hand holding mechanism  24  has a holding bearing  24   a  fixed to the feeding/releasing material arm  21 , and a holding mechanism shaft  24   b  which can be slidably supported and precisely positioned on the holding bearing  24   a . The holding mechanism shaft  24   b  can be slidably supported with respect to the holding bearing  24   a  in an axial direction of the holding mechanism shaft  24   b  by a vertically driving source (not illustrated). The axial direction of the holding mechanism shaft  24   b  is substantially parallel with the axial direction of the arm shaft part  26 . 
     A holding hand  12  is attached to a free end of the holding mechanism shaft  24   b . The holding hand  12  is located at a position faced to an object to be carried by pivoting the feeding/releasing material arm  21 . By sliding the holding mechanism shaft  24   b  with respect to the holding bearing  24   a , the holding hand  12  is separated from and connected to the object to be carried, and simultaneously, the object to be carried which is held by the holding hand  12  is lifted from a placing location or is drawn close to the placing location. 
     The angular velocity sensor  32  is fixed at a side opposite to the holding hand  12  to the hand holding mechanism  24  attached with the holding hand  12 . That is, the angular velocity sensor  32  is fixed to a front end of the feeding/releasing material arm  21  to measure an angular velocity of the feeding/releasing material arm  21  to be pivoted. 
     The feeding/releasing material device control unit  30  wholly controls the operation of each part of the feeding/releasing material device  10  based on a control program previously put via an information input/output device (not illustrated). 
     Functional Configuration of Robot Mechanism Drive 
     Next, the functional configuration of driving the robot mechanism  20  will be described with reference to  FIG. 2 .  FIG. 2  is a block diagram illustrating the functional configuration of driving the robot mechanism. 
     As described above, the feeding/releasing material device  10  includes the arm driving motor  22 , the arm driving mechanism  23 , the angular velocity sensor  32 , the angle sensor  34 , and the feeding/releasing material device control unit  30  in order to pivot the feeding/releasing material arm  21 . 
     As the angular velocity sensor  32 , for example, a gyro sensor may be used. As the angle sensor  34 , for example, an encoder may be used. The feeding/releasing material arm  21  corresponds to an arm, the robot mechanism  20  corresponds to a robot, the arm driving motor  22  corresponds to a driving source, and the angular velocity sensor  32  corresponds to an inertia sensor. 
     As shown in  FIG. 2 , the feeding/releasing material device control unit  30  includes a robot controller  31  for controlling the arm driving motor  22 . The robot controller  31  has a control command generating part  36 , a control conversion determining part  37 , an arm operation control part  38 , and a motor driver  39 . 
     The control command generating part  36  outputs an operation command for the feeding/releasing material arm  21  so as to execute the operation command of the robot mechanism  20  based on an operation command of feeding or releasing a material. The operation command is input to the feeding/releasing material device  10  from an input device (not illustrated). The operation command of the robot mechanism  20  based on the operation command is output to the control command generating part  36  from an overall control part (not illustrated) provided in the feeding/releasing material device control unit  30 . The operation command of the feeding/releasing material arm  21  which is output from the control command generating part  36 , for example, a trace of the front end of the feeding/releasing material arm  21  is commanded as an angle of the feeding/releasing material arm  21  every time. 
     The arm operation control part  38  outputs a control signal of the arm driving motor  22  to execute the operation command of the feeding/releasing material arm  21  which is output from the control command generating part  36 . The arm operation control part  38  has angle information using control part  38   a  and an angle information and angular velocity information using control part  38   b . The angle information using control part  38   a  generates and outputs an optimum control signal of the arm driving motor  22  in accordance with the angle information from the angle sensor  34  so as to execute the operation command of the feeding/releasing material arm  21 . The angle information and angular velocity information using control part  38   b  generates and outputs an optimum control signal of the arm driving motor  22  in accordance with the angle information from the angle sensor  34  and the angular velocity information from the angular velocity sensor  32  so as to execute the operation command of the feeding/releasing material arm  21 . The conversion of the angle information using control part  38   a  and the angle information and angular velocity information using control part  38   b  is determined by the control conversion determining part  37 . The angle information using control part  38   a  and the angle information and angular velocity information using control part  38   b  may install a dedicated hardware, respectively, or a single hardware may be used as the angle information using control part  38   a  or the angle information and angular velocity information using control part  38   b  by a control program. The arm operation control part  38 , or the angle information using control part  38   a  and the angle information and angular velocity information using control part  38   b  provided in the arm operation control part  38  correspond to the arm operation control unit. 
     The control conversion determining part  37  selects and determines the use of the angle information using control part  38   a  or the angle information and angular velocity information using control part  38   b . The control conversion determining part  37  selects and determines the use of the angle information using control part  38   a  or the angle information and angular velocity information using control part  38   b  in accordance with the angle information from the angle sensor  34 , the angular velocity information from the angular velocity sensor  32 , or the operation command of the feeding/releasing material arm  21  from the control command generating part  36 . 
     Pivot of Feeding/Releasing Material Arm  21   
     Next, the process of positioning the holding hand  12  which is installed at the front end of the feeding/releasing material arm  21 , at an appropriate position by controlling the drive of the arm driving motor  22  and pivoting the feeding/releasing material arm  21  will be described with reference to  FIGS. 3 and 4 .  FIG. 3  is a flowchart illustrating the process of pivoting the feeding/releasing material arm by controlling the drive of the arm driving motor.  FIGS. 4A and 4B  are explanatory views illustrating an example of a threshold value of the angular velocity as a standard of converting the control.  FIG. 4A  is a diagram illustrating an example of a relationship between a time lapse and an angular velocity, and a threshold value of the angular velocity while the feeding/releasing material arm is pivoted.  FIG. 4B  is a diagram illustrating an example of a relationship between a time lapse and an angular velocity, and a threshold value of the angular velocity while the feeding/releasing material arm is stopped. 
     First, in a step S 21  in  FIG. 3 , it is determined whether there is a motor stop command or not. The motor stop command is a command of stopping the arm driving motor  22  to complete the control. 
     If there is the motor stop command (YES in step S 21 ), the feeding/releasing material arm  21  is pivoted by controlling the drive of the arm driving motor  22  to complete the process of positioning the holding hand  12  which is located at the front end of the feeding/releasing material arm  21 , at the appropriate position. 
     If there is no motor stop command (NO in step S 21 ), it proceeds to step S 22 . 
     Next, in step S 22 , the control command values, the angle information, and the angular velocity information are obtained. More specifically, the control command value output from the control command generating part  36  and input to the arm operation control part  38  is input to the control conversion determining part  37 . The angle information on the pivot angle of the feeding/releasing material arm  21  which is obtained from the pivot angle of the arm driving motor  22  measured by the angle sensor  34  connected to the arm driving motor  22  is input to the control conversion determining part and the arm operation control part  38 . The angular velocity information on the angular velocity of the feeding/releasing material arm  21  which is measured by the angular velocity sensor  32  fixed near to the front end of the feeding/releasing material arm  21  is input to the control conversion determining part  37  and the arm operation control part  38 . 
     Next, in step S 23 , the control conversion determining part  37  determines whether the angular velocity of the feeding/releasing material arm  21  is more than a predetermined threshold value or not based on the angular velocity information output from the angular velocity sensor  32 . The predetermined threshold value is indicated by a threshold value S. 
     If the angular velocity of the feeding/releasing material arm  21  is more than the predetermined threshold value S (YES in step S 23 ), the control conversion determining part determines to use the angle information and angular velocity information using control part  38   b , and it proceeds to step S 24 . 
     In step S 24 , the angle information and angular velocity information using control part  38   b  calculates a torque command value from the control command value, the angle information, and the angular velocity information. 
     If the angular velocity of the feeding/releasing material arm  21  is less than the predetermined threshold value S (NO in step S 23 ), the control conversion determining part  37  determines to use the angle information using control part  38   a , and it proceeds to step S 25 . 
     In step S 25 , the angle information using control part  38   a  calculates a torque command value from the control command value, and the angle information. 
     As shown  FIG. 4A , in a step in which the feeding/releasing material arm  21  starts to pivot and the angular velocity is less than the threshold value S and a step in which it approaches the target position and the angular velocity is less than the threshold value S, the angular velocity information is not used, and the control is performed by using the control command value and the angle information. The control utilizes a PID (Proportional Integral Differential) control based on, for example, the angle of the angle sensor or the angular velocity of its differential value. In this instance, the PID control or the like corresponds to the second control. 
     At a step in which the angular velocity is higher than the threshold value S in the middle of the pivoting motion, the control is performed by utilizing the angular velocity information, the control command value and the angle information. The control utilizes a control method, for example, a so-called state feedback control. In this instance, the state feedback control or the like corresponds to the first control. 
     The angular velocity indicated by a double-dotted chain line in  FIGS. 4A and 4B  is an angular velocity designated for every lapse time as the control command value. The angular velocity indicated by a broken line in  FIGS. 4A and 4B  is an example of an angular velocity for every lapse time in the case where the PID control is performed based on the angle of the angle sensor using the control command value and the angle information, or the angular velocity of its differential value. The angular velocity indicated by the solid line in  FIGS. 4A and 4B  is an example of an angular velocity for every lapse time in the case where the state feedback control or the like is performed by using the control command value, the angular velocity information and the angle information. 
     In this instance,  FIGS. 4A and 4B  show the solid line indicating the angular velocity in the case of performing the state feedback control or the like at a slow side in time in order to apparently separate the broken line indicating the angular velocity in the case of performing the PID control from the solid line indicating the angular velocity in the case of performing the state feedback control or the like. 
     Subsequent to step S 24  or step S 25 , the torque command value calculated and obtained by the angle information using control part  38   a  or the angle information and angular velocity information using control part  38   b  is input to the motor driver  39  in step S 26 . 
     Next, in step S 27 , electric power corresponding to the torque command value is supplied to the arm driving motor  22  by the motor driver  39 . The arm driving motor  22  generates a torque corresponding to the supplied electric power. 
     Then, in step S 28 , the arm driving mechanism  23  connected to the arm driving motor  22  is operated by the torque generated by the arm driving motor  22 , and the angular velocity of the feeding/releasing material arm  21  connected to the arm driving motor  22  via the arm driving mechanism  23  is accelerated or decelerated by the torque generated by the arm driving motor  22 . 
     Subsequent to step S 28 , it proceeds to step S 21 , and in a case in which there is the motor stop command in step S 21  (YES in step S 21 ), the feeding/releasing material arm  21  is pivoted by controlling the drive of the arm driving motor  22  to complete the process of positioning the holding hand  12 , which is installed at the front end of the feeding/releasing material arm  21 , at a predetermined position. 
     As shown in  FIG. 4B , in the case in which the control using the control command value and the angle information is performed, residual vibration may be generated by pivoting the feeding/releasing material arm  21  so as to return the holding hand  12  passing through the wanted position. By generation of the residual vibration, a time is required until the feeding/releasing material arm  21  stops after it almost reaches the wanted position, that is, the residual vibration stabilized. 
     In the case in which the control using the control command value, the angular velocity information and the angle information is performed, the vibration is almost not generated. As a result, until the feeding/releasing material arm  21  almost approaches the wanted position and then is stopped, the time is not required. In the case in which the noise is carried in the angular velocity information, since the vibration is generated by the noise, the precision is deteriorated. It is possible to exclude the influence of the noise by increasing the threshold value of the angular velocity converting the control than the angular velocity of the vibration resulted from the noise. By converting the control using the control command value and the angle information, it is possible to suppress the generation of heavy vibration in comparison with the case of using the angular velocity information including the noise. 
     In addition, by lowering the threshold value of the angular velocity converting the control to less than the maximum angular velocity of the residual vibration in the case in which the control using the control command value and the angle information is performed, it is possible to suppress the vibration from generating when the control using the control command value, the angular velocity information and the angle information is performed prior to the time converting the control. For this reason, in comparison with a case of performing the control using the control command value and the angle information without performing the control using the control command value, the angular velocity information and the angle information, because the maximum angular velocity of the residual vibration is lowered, it is possible to decrease the time until the residual vibration stabilized. 
     Embodiment 2 
     A second embodiment of a robot, a carriage device and a control method using an inertia sensor will now be described. In this embodiment, a feeding/releasing material device  210  which is an example of the carriage device includes substantially the same mechanical configuration as that of the feeding/releasing material device  10  which is described by reference to  FIG. 1  in the first embodiment. The functional configuration of the robot mechanism drive and the process of pivoting a feeding/releasing material arm  21 , which are different from a part of the feeding/releasing material device  10 , will be described. 
     Functional Configuration of Robot Mechanism Drive 
     First, the functional configuration of driving the robot mechanism  20  in the feeding/releasing material device  210  according to the embodiment will be described with reference to  FIG. 5 .  FIG. 5  is a block diagram illustrating the functional configuration of driving the robot mechanism. 
     Similar to the feeding/releasing material device  10 , the feeding/releasing material device  210  includes an arm driving motor  22 , an arm driving mechanism  23 , an angular velocity sensor  32 , an angle sensor  34 , and a feeding/releasing material device control unit  230  in order to pivot a feeding/releasing material arm  21 . 
     As shown in  FIG. 5 , the feeding/releasing material device control unit  230  includes a robot controller  231  for controlling the arm driving motor  22 . The robot controller  231  has a control command generating part  36 , a control conversion determining part  237 , an arm operation control part  238 , a gain adjusting part  235 , and a motor driver  39 . 
     The control command generating part  36  outputs an operation command for the feeding/releasing material arm  21  so as to execute the operation command of the robot mechanism  20  based on an operation command of feeding or releasing a material. The operation command is input to the feeding/releasing material device  210  from an input device (not illustrated). The operation command of the robot mechanism  20  based on the operation command is output to the control command generating part  36  from an overall control part (not illustrated) provided in the feeding/releasing material device control unit  230 . The operation command of the feeding/releasing material arm  21  which is output from the control command generating part  36 , for example, a trace of the front end of the feeding/releasing material arm  21  is commanded as an angle of the feeding/releasing material arm  21  every time. 
     The arm operation control part  238  outputs a control signal of the arm driving motor  22  to execute the operation command of the feeding/releasing material arm  21  which is output from the control command generating part  36 . The arm operation control part  238  has an angle information and angular velocity information using control part  238   b . The angle information and angular velocity information using control part  238   b  generates and outputs an optimum control signal of the arm driving motor  22  in accordance with the angle information from the angle sensor  34  and the angular velocity information from the angular velocity sensor  32  so as to execute the operation command of the feeding/releasing material arm  21 . The gain adjusting part  235  adjusts and outputs a gain of the angular velocity information when angle information and angular velocity information using control part  238   b  generates the control signal of the arm driving motor  22  in accordance with the angle information and the angular velocity information. The conversion of the gain of the angular velocity information is determined by the control conversion determining part  237 . In this instance, the gain adjusting part  235  and the control conversion determining part  237  correspond to the control conversion determining part. 
     The gain of the angular velocity information corresponds to a weighted constant of the inertial force information. The arm operation control part  238  or the angle information and angular velocity information using control part  238   b  provided in the arm operation control part  238  corresponds to the arm operation control part. 
     The control conversion determining part  237  determines the conversion of the gain of the angular velocity information in accordance with the angle information from the angle sensor  34 , the angular velocity information from the angular velocity sensor  32 , or the operation command of the feeding/releasing material arm  21  from the control command generating part  36 . 
     Pivot of Feeding/Releasing Material Arm  21   
     Next, in the feeding/releasing material device  210 , the process of positioning the holding hand  12  which is installed at the front end of the feeding/releasing material arm  21 , at an appropriate position by controlling the drive of the arm driving motor  22  and pivoting the feeding/releasing material arm  21  will be described with reference to  FIG. 6 .  FIG. 6  is a flowchart illustrating the process of pivoting the feeding/releasing material arm by controlling the drive of the arm driving motor. 
     First, in a step S 41  in  FIG. 6 , it is determined whether there is a “motor stop command” or not. The motor stop command is a command of stopping the arm driving motor  22  to complete the control. 
     If there is the motor stop command (YES in step S 41 ), the feeding/releasing material arm  21  is pivoted by controlling the drive of the arm driving motor  22  to complete the process of positioning the holding hand  12  which is located at the front end of the feeding/releasing material arm  21 , at the appropriate position. 
     If there is no motor stop command (NO in step S 41 ), it proceeds to step S 42 . 
     Next, in step S 42 , the control command values, the angle information, and the angular velocity information are obtained. More specifically, the control command value output from the control command generating part  36  and input to the arm operation control part  238  is input to the control conversion determining part  237 . The angle information on the pivot angle of the feeding/releasing material arm  21  which is obtained from the pivot angle of the arm driving motor  22  measured by the angle sensor  34  connected to the arm driving motor  22  is input to the control conversion determining part  237  and the arm operation control part  238 . The angular velocity information on the angular velocity of the feeding/releasing material arm  21  which is measured by the angular velocity sensor  32  fixed near to the front end of the feeding/releasing material arm  21  is input to the control conversion determining part  237  and the arm operation control part  238 . 
     Next, in step S 43 , the control conversion determining part  237  determines whether the angular velocity of the feeding/releasing material arm  21  is more than a predetermined threshold value or not based on the angular velocity information output from the angular velocity sensor  32 . The predetermined threshold value is indicated by a threshold value S. 
     If the angular velocity of the feeding/releasing material arm  21  is more than the predetermined threshold value S (YES in step S 43 ), the control conversion determining part  37  determines the gain of the angular velocity information as 1, and it proceeds to step S 45 . 
     If the angular velocity of the feeding/releasing material arm  21  is less than the predetermined threshold value S (NO in step S 43 ), the control conversion determining part  237  determines to convert the gain of the angular velocity information, and it proceeds to step S 44 . 
     In step S 44 , the gain adjusting part  235  determines the gain of the angular velocity information as a value of 1 or less than when the angle information and angular velocity information using control part  238   b  generates the control signal of the arm driving motor  22  based on the angle information and the angular velocity information, and then outputs it to the angle information and angular velocity information using control part  238   b . Next to step S 44 , it proceeds to step S 45 . 
     Next to step S 43  or step S 44 , in step S 45 , the angle information and angular velocity information using control part  238   b  calculates a torque command value from the control command value, the angle information, the angular velocity information and the gain of the angular velocity information. 
     Next, in step S 46 , the torque command value calculated and obtained by the angle information and angular velocity information using control part  238   b  is input to the motor driver  39 . 
     Then, in step S 47 , the electric power corresponding to the torque command value is supplied to the driving motor  22  by the motor driver  39 . The arm driving motor  22  generates the torque corresponding to the supplied electric power. 
     Next, in step S 48 , the arm driving mechanism  23  connected to the arm driving motor  22  is operated by the torque generated by the arm driving motor  22 , and the angular velocity of the feeding/releasing material arm  21  connected to the arm driving motor  22  via the arm driving mechanism  23  is accelerated or decelerated by the torque generated by the arm driving motor  22 . 
     Subsequent to step S 48 , it proceeds to step S 41 , and in a case in which there is the motor stop command in step S 41  (YES in step S 41 ), the feeding/releasing material arm  21  is pivoted by controlling the drive of the arm driving motor  22  to complete the process of positioning the holding hand  12 , which is installed at the front end of the feeding/releasing material arm  21 , at a predetermined position. 
     Embodiment 3 
     Next, the third embodiment will be described as a modified example of the first embodiment and the second embodiment. In this embodiment, it will be described another embodiment of the threshold value which is a criteria to determine whether the angular velocity information is used or not used or to determine a value of the gain, when the torque command value is calculated in the first embodiment or the second embodiment. 
     Example 1 of Threshold Value 
     First, another example of defining the threshold value on the angular velocity information will be described with reference to  FIGS. 7A and 7B .  FIGS. 7A and 7B  are explanatory views illustrating an example of the threshold value of the angular velocity as a standard of converting the control.  FIG. 7A  is a diagram illustrating an example of a relationship between a time lapse and the angular velocity, and a threshold value of the angular velocity while the feeding/releasing material arm is pivoted.  FIG. 7B  is a diagram illustrating an example of angular velocity information. 
     The angular velocity indicated by a double-dotted chain line in  FIG. 7A  is an angular velocity designated for every lapse time as the control command value, and the angular velocity indicated by the solid line is an example of an angular velocity for every lapse time in the case where the state feedback control or the like is performed by using the control command value, the angular velocity information and the angle information. The angular velocity indicated by the solid line in  FIG. 7B  is an angular velocity measured by using an angular velocity sensor with a wide dynamic range, and the angular velocity indicated by a broken line is an angular velocity measured by using an angular velocity sensor with a relatively narrow dynamic range. 
     In general, the output of the angular velocity sensor is output as, for example, a voltage, and the voltage to be output is finite. For this reason, if a resolution is increased, the dynamic range is narrowed. The dynamic range of the angular velocity sensor shown in  FIG. 7B  with the relatively narrow dynamic range is approximately 300 dps, and as shown in  FIG. 7B , if the angular velocity of the object to be measured is more than the dynamic range, the output of the angular velocity becomes a constant value. For this reason, in a case in which the angular velocity of the object to be measured is more than the dynamic range, if the control of the robot is performed by using the angular velocity information, the possibility of performing wrong control is high. It is possible to increase the resolution by narrowing the dynamic range. Therefore, since even small fluctuation of the angular velocity can be detected, the precise control can be performed. 
     In the example of the threshold value, as shown in  FIG. 7A , in a case in which the angular velocity is more than the threshold value S 2 , the angular velocity information is not used, or the control with the gain of the angular velocity information less than 1 is performed. 
     Example 2 of Threshold Value 
     Next, an example of defining the threshold value on the angle information will be described with reference to  FIGS. 8A and 8B .  FIGS. 8A and 8B  are explanatory views illustrating an example of the threshold value of the angle as a standard of converting the control.  FIG. 8A  is a diagram illustrating an example of a relationship between a time lapse and the pivot angle, and a threshold value of the angle while the feeding/releasing material arm is pivoted.  FIG. 8B  is a diagram illustrating an example of a relationship between a time lapse and the pivot angle, and a threshold value of the angle while the feeding/releasing material arm is stopped. 
     As shown in  FIG. 8A , in a step in which the feeding/releasing material arm  21  is pivoted and the pivoted angle is more than the threshold value S 3 , the PID control is performed, for example, based on the angle of the angle sensor using the control command value and the angle information, without using the angular velocity information, or the angular velocity of its differential value, or, for example, the state feedback control using the control command value and the angle information, and the angular velocity information, of which the gain is set to be 1 or less, is performed. In a step in which the rotation operation starts and the pivot angle is less than the threshold value S 3 , the control using the angular velocity information, the control command value and the angle information is performed. The control uses, for example, the state feedback control. 
     The pivot angle indicated by a double-dotted chain line in  FIGS. 8A and 8B  is an angle designated for every lapse time as the control command value. The angle indicated by a broken line is an example of an angle for every lapse time in the case where the PID control is performed based on the angle of the angle sensor using the control command value and the angle information, or the angular velocity of its differential value. The angle indicated by the solid line is an example of an angle for every lapse time in the case where the state feedback control or the like is performed by using the control command value, the angular velocity information and the angle information. 
     In this instance,  FIGS. 8A and 8B  show the solid line indicating the angle in the case of performing the state feedback control or the like at a slow side in time in order to apparently separate the broken line indicating the angle in the case of performing the PID control from the solid line indicating the angle in the case of performing the state feedback control or the like. 
     As shown in  FIG. 8B , in the case in which the control using the control command value and the angle information is performed, residual vibration may be generated by pivoting the feeding/releasing material arm  21  so as to return the holding hand  12  passing through the wanted position. By generation of the residual vibration, a time is required until the feeding/releasing material arm  21  stops after it almost reaches the wanted position, that is, the residual vibration stabilized. 
     In the case in which the control using the control command value information, the angular velocity information and the angle information is performed, the vibration is almost not generated. As a result, until the feeding/releasing material arm  21  almost approaches the wanted position and then is stopped, the time is not required. 
     In the case in which the noise is carried in the angular velocity information, since the vibration is generated by the noise, the precision is deteriorated. It is possible to exclude the influence of the noise by setting the threshold value of the angle converting the control far away from the angle of the vibration with respect to the wanted stop position. By converting the control using the control command value and the angle information, it is possible to suppress the generation of heavy vibration in comparison with the case of using the angular velocity information including the noise. 
     In addition, by setting the threshold value of the angle converting the control as an angle of a position closer than the maximum angle of the residual vibration in the case in which the control using the control command value and the angle information is performed with respect to the wanted stop position, it is possible to suppress the vibration from generating when the control using the control command value, the angular velocity information and the angle information is performed prior to the time converting the control. It may be assumed that the pivot position (angle) of the feeding/releasing material arm  21  at the time of converting the control is close to the wanted stop position relative to the maximum angle of the residual vibration in the case of performing the control using the control command value and the angle information. Even in the control using the control command value and the angle information, there is a high possibility to position the feeding/releasing material arm  21  at the wanted stop position, without generating the vibration exceeding the maximum angle of the residual vibration in the case of performing the control using the control command value and the angle information. For this reason, in comparison with a case of performing the control using the control command value and the angle information without performing the control using the control command value, the angular velocity information and the angle information, the maximum angle of the residual vibration is lowered, so that it is possible to decrease the time until the residual vibration stabilized. 
     Example 3 of Threshold Value 
     Next, an example of defining the threshold value on a time axis with a specific point of the control command value will be described with reference to  FIGS. 9A and 9B .  FIGS. 9A and 9B  are explanatory views illustrating an example of the threshold value defined on the time axis with respect to the specific point of the control command value as a standard of converting the control.  FIG. 9A  is a diagram illustrating an example of a relationship between a time lapse and the pivot angle, and a threshold value defined on the time axis with respect to the wanted stop position which is a specific point of the control command value, while the feeding/releasing material arm is pivoted.  FIG. 9B  is a diagram illustrating an example of a relationship between a time lapse and the angular velocity near to the wanted stop position which is the specific point of the control command value, and a threshold value defined on the time axis with respect to the wanted stop position which is a specific point of the control command valued. 
     The angular velocity indicated by a double-dotted chain line in  FIGS. 9A and 9B  is an angular velocity designated for every lapse time as the control command value. The angle indicated by a solid line is an example of an angular velocity for every lapse time in the case where the state feedback control or the like is performed by using the control command value and the angular velocity information, and the angle information. 
     As shown in  FIGS. 9A and 9B , in the control command value, after the angular velocity becomes zero and then the time T 1  of a threshold time passes from the time when it reaches the wanted stop position, the PID control is performed, for example, based on the angle of the angle sensor using the control command value and the angle information, without using the angular velocity information, or the angular velocity of its differential value, or, for example, the state feedback control using the control command value and the angle information, and the angular velocity information, of which the gain is set to be 1 or less, is performed. After the pivot operation starts, the control using the angular velocity information, the control command value and the angle information is performed during the time when the angular velocity becomes zero and between the time when the angular velocity becomes zero to the time T 1  in the control command value. The control uses, for example, the state feedback control. 
     As shown in  FIG. 9B , if a predetermined time T 1  passes from the time when the angular velocity of the control command value becomes zero, the angular velocity of the feeding/releasing material arm  21  becomes close to zero. In a state in which the angular velocity of the feeding/releasing material arm  21  does not become zero and the torque command value to drive the arm driving motor  22  is output, there is high possibility for abnormality to occur in the control system. The abnormality of the control system is, for example, a state in which the angular velocity sensor  32  is out of order, or the angular velocity information is not precise due to the noise or the like. Alternatively, by performing the control using the control command value and the angle information, or the control using the control command value and the angle information, and the angular velocity information of which the gain is set to be 1 or less, it is possible to exclude these abnormal factors. 
     If the predetermined time T 1  passes from the time when the angular velocity of the control command value becomes zero, it may be assumed that the pivot position (angle) of the feeding/releasing material arm  21  is close to the wanted stop position. For this reason, in the control using the control command value and the angle information, it is highly possible to position the feeding/releasing material arm  21  at the wanted stop position, without generating the vibration almost. 
     Embodiment 4 
     A fourth embodiment of a robot, a carriage device and a control method using an inertia sensor will now be described. In this embodiment, an example of the robot or the carriage device different from the feeding/releasing material device described in the first embodiment or the second embodiment will be described. 
     Feeding/Releasing Material Device 
     As the feeding/releasing material device according to one embodiment of the robot, the carriage device, and the control method using the inertia sensor, a feeding/releasing material device  310  which is different from the feeding/releasing material device  10  or the feeding/releasing material device  210  described in the first embodiment or the second embodiment will be described with reference to  FIG. 10 .  FIG. 10  is a perspective view schematically illustrating an external configuration of the feeding/releasing material device. 
     As shown in  FIG. 10 , the feeding/releasing material device  310  includes a holding hand  12 , a robot mechanism  320 , a feeding/releasing material device control unit  330 , an angular velocity sensor  332   a , an angular velocity sensor  332   b , and two angle sensors (not illustrated). 
     The robot mechanism  320  includes a hand holding mechanism  24 , a feeding/releasing material arm  321 , an arm shaft part  326 , and a base  328 . The base  328  supports the arm shaft part  326  in such a way that the arm shaft part can be rotated around a rotational shaft of the arm shaft part  326  via a built-in bearing mechanism (not illustrated) and can be precisely positioned. The arm shaft part  326  is connected to an arm driving motor (not illustrated) built in the base  328  via an arm driving mechanism (not illustrated), and thus is pivoted by the arm driving motor. The arm driving motor is connected to the angle sensor, and a pivot angle of the arm driving motor is measured by the angle sensor. 
     An end portion of the arm shaft part  326  which is opposite to its end portion supported by the base  328  is fixed to one end portion of the feeding/releasing material arm  321 . The feeding/releasing material arm  321  has an arm portion  321   a , an arm portion  321   b , and an arm articulated portion  323 . One end of the arm portion  321   a  is connected to one end of the arm portion  321   b  via the arm articulated portion  323 . The other end of the arm portion  321   b  which is opposite to the one end connected to the arm articulated portion  323  is fixed to the arm shaft part  326 . Since the arm shaft part  326  is freely pivoted around the rotational shaft of the arm shaft part  326  with respect to the base  328 , the arm portion  321   b  with one end fixed to the arm shaft part  326  is freely pivoted around the rotational shaft of the arm shaft part  326  with respect to the base  328 . 
     The arm portion  321   b  supports the arm portion  321   a  in such a way that it is pivoted around the rotational shaft of the arm articulated portion  323  through the arm articulated portion  323 . The portion of the arm articulated portion, to which the arm portion  321   a  of the arm articulated portion  323  is fixed, is connected to an arm portion driving motor (not illustrated) built in the arm portion  321   b  via an arm portion driving mechanism (not illustrated), and is pivoted by the arm portion driving motor. An angle of the arm portion  321   a  and the arm portion  321   b  with respect to the arm articulated portion  323  can be adjusted. That is, the feeding/releasing material arm  321  can be flexibly extended with respect to the arm articulated portion  323 . The arm angle sensor is connected to the arm portion driving motor, and the pivot angle of the arm portion driving motor is measured by the arm angle sensor. It is possible to measure the pivot angle of the arm portion  321   a  with respect to the arm portion  321   b  by measuring the pivot angle of the arm portion driving motor. 
     An axial direction of the rotational shaft of the arm shaft part  326  is substantially parallel with an axial direction of the rotational shaft of the arm articulated portion  323 . 
     The end portion of the arm shaft portion  321   a  which is opposite to the end thereof fixed to the arm articulated portion  323  is fixed to the hand holding mechanism  24 . The hand holding mechanism  24  has a holding bearing  24   a  fixed to the arm portion  321   a , and a holding mechanism shaft  24   b  which can be slidably supported and precisely positioned on the holding bearing  24   a . The holding mechanism shaft  24   b  can be slidably supported with respect to the holding bearing  24   a  in an axial direction of the holding mechanism shaft  24   b  by a vertically driving source (not illustrated). The axial direction of the holding mechanism shaft  24   b  is substantially parallel with the axial direction of the rotational shaft of the arm shaft part  326  and the axial direction of the rotational shaft of the arm articulated portion  323 . 
     A holding hand  12  is attached to a free end of the holding mechanism shaft  24   b . The holding hand  12  is located at a position faced to an object to be carried by rotating and flexibly extending the feeding/releasing material arm  321 . By sliding the holding mechanism shaft  24   b  with respect to the holding bearing  24   a , the holding hand  12  is separated from and connected to the object to be carried, and simultaneously, the object to be carried which is held by the holding hand  12  is lifted from a placing location or is drawn close to the placing location. 
     The angular velocity sensor  332   a  is fixed to the hand holding mechanism  24  attached with the holding hand  12 , opposite to the holding hand  12 . That is, the angular velocity sensor  332   a  is fixed to the front end of the arm portion  321   a  to measure the angular velocity of the arm portion  321   a  to be pivoted. 
     The angular velocity sensor  332   b  is fixed to the side of one end of the arm portion  321   b  which is connected to the arm articulated portion  323 . Accordingly, the angular velocity sensor  332   b  is fixed to the front end of the arm portion  321   b  to measure the angular velocity of the arm portion  321   b  to be pivoted. 
     The feeding/releasing material device control unit  330  controls the overall operation of each part of the feeding/releasing material device  310  based on a control program previously input through an information input/output device (not illustrated). The feeding/releasing material device control unit  330  can control the operation of the arm portion  321   b  based on angular velocity information from the angular velocity sensor  332   b  and angle information from the angle sensor built in the base  328 . Simultaneously, relative movement of the arm portion  321   a  with respect to the arm portion  321   b  can be controlled based on angular velocity information from the angular velocity sensor  332   a  and angle information from the arm angle sensor built in the arm portion  321   b . That is, the operation of the feeding/releasing material arm  321  generally handling the operation of the arm portion  321   a  and the arm portion  321   b  can be controlled by using the angular velocity information and the angle information, similar to the above-mentioned embodiments. 
     Carriage Device 
     Next, the carriage device including a holding device for holding a target object which moves in parallel along an orthogonal coordinates system will be described with reference to  FIGS. 11A and 11B .  FIGS. 11A and 11B  are perspective views schematically illustrating the external configuration of the carriage device.  FIG. 11A  is a perspective view schematically illustrating an external configuration of a ceiling suspension carriage device.  FIG. 11B  is a perspective view schematically illustrating an external configuration of a head carriage device in a printing machine. 
     Ceiling Suspension Carriage Device 
     As shown in  FIG. 11A , a ceiling suspension carriage device  410  includes a main scanning direction movable mechanism  402 , a subsidiary scanning direction movable mechanism  403 , a lift movable mechanism  404 , a holding mechanism  412 , a distance sensor, an acceleration sensor  432 , and a carriage device control unit (not illustrated). 
     The main scanning direction movable mechanism  402  has a pair of main scanning guide rails  421  and  421  extending in a main scanning direction, a main scanning linear motor formed on the main scanning guide rail  421 , and a main scanning slider formed on a main plate  422 . The scanning plate  422  is placed between the pair of main scanning guide rails  421  and  421 , and extends in a subsidiary scanning direction substantially perpendicular to the main scanning direction. The scanning plate  422  is freely moved in the main scanning direction by the main scanning linear motor and the main scanning slider. The pair of main scanning guide rails  421  and  421  is suspended from, for example, a ceiling. 
     The subsidiary scanning direction movable mechanism  403  has a subsidiary scanning linear motor formed on the scanning plate  422 , and a subsidiary scanning slider formed on a subsidiary scanning frame  423 . The subsidiary scanning frame  423  is freely moved in the subsidiary scanning direction by the subsidiary scanning linear motor and the subsidiary scanning slider. 
     The lift movable mechanism  404  has a ball bearing placed in the subsidiary scanning frame  423 , a ball bearing driving motor, and a ball screw fixed to a lift shaft  424 . The lift shaft  424  is lifted by the ball bearing, the ball bearing driving motor and the ball screw. 
     The holding mechanism  412  fixed to the lift shaft  424  at a position opposite to the ball screw is moved to an optional position in the main scanning direction and the subsidiary scanning direction by the main scanning direction movable mechanism  402  and the subsidiary scanning direction movable mechanism  403 , and can be detached from and comes into contact with the target object by the lift movable mechanism  404 . 
     The carriage device control unit controls the overall operation of each part of the ceiling suspension carriage device  410  based on the control program which is previously input via the information input/output device (not illustrated). 
     The main scanning linear motor, the subsidiary scanning linear motor, and the ball bearing driving motor are respectively connected to a distance sensor for measuring a driving distance by the motors. 
     The acceleration sensor  432   a , the acceleration sensor  432   b  or the acceleration sensor  432   c  are fixed to the subsidiary scanning linear motor  423  or the holding mechanism  412 . The acceleration sensor  432   a , the acceleration sensor  432   b  and the acceleration sensor  432   c  can measure the acceleration in the main scanning direction, the subsidiary scanning direction or the lift direction. 
     The movement of the holding mechanism  412  can be controlled by the moving distance information in each direction by the distance sensor connected to the main scanning linear motor, the subsidiary scanning linear motor or the ball bearing driving motor, and the acceleration information in each direction by the acceleration sensor  432   a , the acceleration sensor  432   b  or the acceleration sensor  432   c . As the distance sensor, for example, a linear encoder may be used. The distance sensor corresponds to a position sensor. 
     When the movement of the holding mechanism  412  is controlled by using the moving distance information and the acceleration information, a threshold value is previously set in the moving distance information or the acceleration information, and the control conversion determining unit of the carriage device control unit compares the moving distance information or the acceleration information with the threshold value to determine whether the acceleration information is used or not for the control or to determine a constant to be multiplied to the acceleration information. The operation control part of the carriage device control unit performs the control using the control command value and the moving distance information, the control using the control command value and the moving distance information, and the acceleration information, or the control using the acceleration information resulted by multiplying the control command value and the moving distance information by a gain of the acceleration information, according to the determination of the control conversion determining unit. By performing the control, the operation of the main scanning direction movable mechanism  402 , the subsidiary scanning direction movable mechanism  403  and the lift movable mechanism  404  is controlled, so that the holding mechanism  412  is moved to an optional position to determine the position. 
     Head Carriage Device 
     As shown in  FIG. 11B , the head carriage device  460  is to move an ejection head  462  of the printing machine, and includes a head carriage  476 , a carriage shaft  474 , a driving belt  473 , a driving pulley  472 , a driving motor  471 , an acceleration sensor  482 , and an encoder  484 . The printing machine includes a printing machine control unit (not illustrated) for controlling the overall operation of each part of the printing machine. 
     The driving motor  471  is fixed to a machine frame which is not shown, and the driving pulley  472  is fixed to one end of the driving shaft. The driving belt  473  is located between the driving pulley  472  and a driven pulley (not illustrated), and the driving belt  473  is driven by the driving motor  471 . The carriage shaft  474  is placed in parallel with the extension direction of the driving belt  473 . The head carriage  476  is engaged with and supported by the carriage shaft  474  in such a way that the head carriage can be slid in an axial direction of the carriage shaft  474 . The head carriage  476  is fixed with the driving belt  473 , and is moved along the carriage shaft  474  by driving of the driving belt  473 . The ejection head  462  held by the head carriage  476  is moved in the axial direction of the carriage shaft  474  and is held at an optional position. 
     The printing machine control unit controls the overall operation of each part of the printing machine based on the control program previously input through the information input/output device (not illustrated). 
     The encoder  484  is connected to the driving shaft of the driving motor  471 , and measures the pivot angle of the driving motor  471  to measure the moving distance of the ejection head  462 . The pivot angle information of the driving motor  471  corresponding to the position of the ejection head  462  corresponding to the moving distance is indicated by the position information of the driving motor  471 . The acceleration sensor  482  is fixed to the head carriage  476 , and can measure the acceleration acting on the head carriage  476  by driving of the head carriage  476 . The movement of the ejection head  462  held by the head carriage  476  can be controlled by the position information from the encoder  484  and the acceleration information from the acceleration sensor  482 . The encoder  484  corresponds to a position sensor. 
     When the movement of the ejection head  462  is controlled by using the position information and the acceleration information, a threshold value is previously set in the position information or the acceleration information, and the control conversion determining unit of the printing machine control unit compares the position information or the acceleration information with the threshold value to determine whether the acceleration information is used or not for the control or to determine a weighted constant to be multiplied to the acceleration information. The operation control part of the printing machine control unit performs the control using the control command value and the position information, the control using the control command value and the position information, and the acceleration information, or the control using the acceleration information resulted by multiplying the control command value and the position information by the weighted constant, according to the determination of the control conversion determining unit. By performing the control, the operation of the driving motor  471  is controlled, so that the ejection head  462  held by the head carriage  476  is moved to an optional position to determine the position. 
     Laser Printer 
     Next, as an example of controlling rotation of a drum-shaped member, a laser printer  510  will be described with reference to  FIG. 12 .  FIG. 12  is a diagram schematically illustrating a major part of the laser printer. 
     As shown in  FIG. 12 , the laser printer  510  includes a photoreceptor drum  524 , a drum driving motor  522 , an encoder  534 , a driving transmission mechanism  523 , a charging unit  541 , a laser oscillation unit  542 , a toner supply unit  543 , a transfer roller  544 , a fixing roller  546  and a fixing roller  547 , a toner recovery unit  548 , an angular velocity sensor  532 , and a printer control unit (not illustrated). 
     The photoreceptor drum  524  is connected to the drum driving motor  522  via the driving transmission mechanism  523 , and is rotated around the rotational shaft by the drum driving motor  522 . The surface of the photoreceptor drum  524  is negatively charged by the charging unit  541 , and an electrostatic portion is remained in a shape of printing by the laser oscillation unit  542  to draw the shape of the printing. The toner supplied by the toner supply unit  543  is adhered to the shape of the charged printing. A sheet  549  is pressed against the photoreceptor drum  524  by the transfer roller  544 , so that the toner is transferred to the sheet  549 . The toner transferred to the sheet  549  is applied by pressure and heat from the fixing roller  546  and the fixing roller  547 , and thus is fixed. Unnecessary toner is recovered from the surface of the photoreceptor drum  524  transferred with the toner by the toner recovery unit  548 , and then the above process is repeated. 
     The printer control unit controls the overall operation of each part of the laser printer  510  based on the control program previously input through the information input/output device (not illustrated). 
     The encoder  534  is connected to the driving shaft of the drum driving motor  522 , and measures the pivot angle of the drum driving motor  522  to measure the rotation angle information of the photoreceptor drum  524  by the encoder  534 . The angular velocity sensor  532  is fixed to the photoreceptor drum  524 , and can obtain the angular velocity information on the pivoting photoreceptor drum  524  from the acceleration sensor  532 . The rotation of the photoreceptor drum  524  can be controlled by the pivot angle information of the drum driving motor  522  by the encoder  534 , and the angular velocity information from the angular velocity sensor  532 . 
     When the rotation of the photoreceptor drum  524  is controlled by using the pivot angle information and the angular velocity information, a threshold value is previously set in the pivot angle information or the angular velocity information, and the control conversion determining unit of the printer control unit compares the pivot angle information or the angular velocity information with the threshold value to determine whether the angular velocity information is used or not for the control or to determine a weighted constant to be multiplied to the angular velocity information. The operation control part of the printer machine control unit performs the control using the control command value and the pivot angle information, the control using the control command value and the pivot angle information, and the angular velocity information, or the control using the angular velocity information resulted by multiplying the control command value and the pivot angle information by the weighted constant, according to the determination of the control conversion determining unit. By performing the control, the operation of the drum driving motor  522  is controlled, so that the photoreceptor drum  524  is rotated at an optional angle. 
     Although preferred embodiments are described with reference to the accompanying drawings, the invention is not limited to the preferred embodiments. The embodiments can be implemented by the following within the range departing from the gist of the invention, and may be variously modified. 
     Modified Example 1 
     In the embodiment, although the example of defining the threshold value for the pivot angle information, the angular velocity information, the moving distance information, the acceleration information or the position information, or the example of defining the threshold value on the time axis with respect to the specific point of the control command value has been described, the object defining the threshold value is not limited thereto. It may be determined whether the angular velocity information or the acceleration information is used or not, by setting the threshold value for the noise affecting the value of the angular velocity information or the acceleration information and using a level of the noise, or the constant which is multiplied to the angular velocity information or the acceleration information may be determined so as to adjust the influence of the angular velocity information or the acceleration information. As the noise affecting the value of the angular velocity information or the acceleration information, there is mechanical vibration of the machine itself, vibration of an apparatus existing around the machine, dispersion of a power supplied to the machine, or surrounding electron noise. 
     Modified Example 2 
     In the embodiment, although the example of defining the threshold value for the angular velocity information by the angular velocity sensor  32  or the acceleration information by the acceleration sensor  432  has been described, the object defining the threshold value is not limited thereto. The threshold value may be defined for the integral value of one or more times of the angular velocity information or the acceleration information. The integral value of the acceleration information is velocity information, and the velocity information may be treated similar to the angular velocity information. The integral value of two times of the acceleration information and the integral value of the angular velocity information is information of the moving distance, and the information of the moving distance may be treated similar to the angle information or the position information. 
     Modified Example 3 
     In the embodiment, although the example of defining the threshold value for the angle information by the angle sensor  34  or the moving distance information by the distance sensor has been described, the object defining the threshold value is not limited thereto. The threshold value may be defined for the differential value of one or more times of the angle information or the moving distance information. The differential value of the angle information or the moving distance information may be treated similar to the angular velocity information as the angular velocity or the moving velocity. The differential value of two times of the angle information or moving distance information may be treated similar to the acceleration information as the angular acceleration or the acceleration. 
     Modified Example 4 
     In the embodiment, the example of defining the threshold value for the pivot angle information, the angular velocity information, the moving distance information, the acceleration information or the position information, or the example of defining the threshold value on the time axis with respect to the specific point of the control command value has been described. Although the object defined with the threshold value is used exclusively when the control is performed, the control may be performed by using plural objects defining the threshold value. For example, in only case in which both the pivot angle information and the angular velocity information exceed the threshold values, the control may be performed by not using the angular velocity information. In a case in which at least one of the pivot angle information and the angular velocity information does not exceed the threshold values, the control may be performed by using the pivot angle information or the angular velocity information. In addition, the pivot angle information, the angular velocity information, the moving distance information, the acceleration information or the position information, or the time axis with respect to the specific point of the control command value may be combined with the noise level affecting the value of the angular velocity information or the acceleration information described in Modified Example 1. In this instance, for example, in a case in which both sides of the pivot angle information, the angular velocity information, the moving distance information, the acceleration information or the position information, or the time axis with respect to the specific point of the control command value, and the noise level exceed the threshold value, the control is performed by not using the angular velocity information. In a case in which at least one side exceeds the threshold value, the control is performed by using pivot angle information and the angular velocity information. Consequently, irrespective of that the noise level such as angular velocity information is maintained in a low level, it is possible to elude the state where the control is performed by not using the angular velocity information, in order to prevent the adverse effect by the noise. 
     Modified Example 5 
     In the embodiment, as an example of the robot and carriage device, although the feeding/releasing material device  10  including the robot mechanism  20 , the feeding/releasing material device  310  including the robot mechanism  320 , the ceiling suspension carriage device  410 , the head carriage device  460  provided in the printing machine, and the drum driving device provided in the laser printer  510  has been described by way of an example, the robot and carriage device which can be appropriately controlled by using the control method using the inertia sensor are not limited to the illustrative devices. By using the control method using the inertia sensor, a device capable of quickly moving the movable body to a predetermined target position and quickly stopping it at the position with high precision can be appropriately controlled.