Patent Publication Number: US-2023132577-A1

Title: Filtering device, control system, and filtering method

Description:
TECHNICAL FIELD 
     The present invention relates to a filtering device, a control system, and a filtering method. 
     BACKGROUND ART 
     Control devices configured to control machinery serving as controlled objects such as robots and construction machines are designed to acquire measurement data including numerical values representative of statuses of controlled machines from sensors configured to produce information about statuses of controlled machines so as to achieve control over controlled machines based on measurement data. As the information about statues of controlled machines, for example, sensors may output various types of measurement data, such as angles from reference positions of predetermined parts, speeds to drive predetermined parts, and forces applied to predetermined parts, to control devices. Control devices are designed to perform feedback control based on measurement data so as to achieve control over controlled machines. In this connection, control devices should inevitably acquire plenty of measurement data superposed with noise. To realize highly-accurate control over controlled machines, control devices need to precisely eliminate noises superposed on measurement data. Patent Document 1 and Patent Document 2 disclose technologies relating to noise elimination. 
     Patent Document 1 discloses techniques as to how to detect the position of a bucket of a backhoe machine relative to its drive part based on detection values of sensors configured to detect angles of various parts of a backhoe machine and how to prevent interference between the bucket and the drive part based on the detected position information. Patent Document 2 discloses techniques as to how to produce an attitude angle according to angular speed and acceleration detected by a measurement device attached to a working machine and how to reduce noise included in the attitude angle. 
     CITATION LIST 
     Patent Literature Document 
     
         
         Patent Document 1: Japanese Patent No. 2672143 
         Patent Document 2: Japanese Patent Application Publication No. 2002-180504 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     The aforementioned noise superposed on measurement data may be varied according to an attitude status and a drive status of a controlled machine serving as a controlled object. For example, it is assumed that the controlled machine would be a hydraulic excavator using an incline sensor configured to measure an angle and an incline of an object according to gravity as a sensor configured to measure information relating to the status of a controlled machine. In this case, an amount of motion acceleration other than gravity should be differentiated between a halting mode and an operating mode of a hydraulic excavator, which may differentiate characteristics of noise superposed on measurement data produced by an incline sensor. To achieve highly-accurate control over a controlled machine, it is necessary to appropriately eliminate noise (e.g., noise superposed on measurement data) according to an attitude status and a drive status of the controlled machine. 
     Accordingly, the present invention aims to provide a filtering device, a control system, and a filtering method which can solve the aforementioned problem 
     Solution to Problem 
     In a first aspect of the present invention, a filtering device is characterized by including a noise-characteristic estimation means configured to estimate the characteristics of noise superposed on measurement data relating to the status of a controlled machine based on the status information representing the status of the controlled machine, and a filtering adjustment means configured to adjust the filtering to eliminate noise based on the estimated noise characteristics. 
     In a second aspect of the present invention, a control system is characterized by including a sensor configured to acquire measurement data relating to the status of a controlled machine, a noise-characteristic estimation means configured to estimate the characteristics of noise superposed on measurement data based on the status information representing the status of the controlled machine, and a filtering adjustment means configured to adjust the filtering to eliminate noise based on the estimated noise characteristics. 
     In a third aspect of the present invention, a filtering method is characterized by estimating the characteristics of noise superposed on measurement data relating to the status of a controlled machine based on the status information representing the status of the controlled machine, and adjusting the filtering to eliminate noise based on the estimated noise characteristics. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to eliminate noise (e.g., noise superposed on measurement data) to be varied according to an attitude status and a drive status of a controlled machine with high accuracy. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a block diagram showing the configuration of a control system according to one exemplary embodiment of the present invention. 
         FIG.  2    is a block diagram showing the hardware configuration of an exterior control apparatus according to one exemplary embodiment of the present invention. 
         FIG.  3    is a block diagram showing the function of a control system according to the first exemplary embodiment. 
         FIG.  4    is a flowchart showing the processing of an exterior control device according to the first exemplary embodiment. 
         FIG.  5    is a block diagram showing the functionality of a control system according to the second exemplary embodiment. 
         FIG.  6    is a block diagram showing the minimum configuration of a filtering device according to one exemplary embodiment of the present invention. 
         FIG.  7    is a flowchart showing the processing of the filtering device having the minimum configuration according to one exemplary embodiment of the present invention. 
     
    
    
     EXEMPLARY EMBODIMENTS TO CARRY OUT THE INVENTION 
     Hereinafter, a control system equipped with a filtering device according to one exemplary embodiment of the present invention will be described with reference to the accompanying drawings. 
       FIG.  1    is a block diagram showing the configuration of a control system according to one exemplary embodiment. A control system  100  includes at least a construction machine  1  serving as an example of a controlled machine, one or multiple sensors  10  configured to measure the status information of the construction machine  1 , and an exterior control device  2 . In the present exemplary embodiment, the construction machine  1  is a hydraulic excavator. 
     For example, the sensor(s)  10  is an incline sensor configured to detect an incline value for each part to be driven in the construction machine  1  as the status information of the construction machine  1 , thus outputting sensing information including the inline value. The sensors  10  are each attached to each driven part so as to detect an incline for each driven part. In the case of a hydraulic excavator serving as the construction machine  1 , for example, driven parts may be each defined as an arm, a boom, or a bucket. In this connection, the sensors  10  may be each configured to detect a physical state of the construction machine  1  other than an incline for each driven part. In the case of a hydraulic excavator serving as the construction machine  1 , for example, the sensor  10  may detect a revolving angle of an upper-revolving structure relative to a lower-traveling structure. In this case, the sensor  1  may be a gyro-sensor or a linear-encoder. Hence, the sensor  10  may output the sensing information representing a revolving angle. Alternatively, the sensor  10  may detect an amount of oil flown into each driven part of the construction machine  1 . In the case of a hydraulic excavator serving as the construction machine  1 , for example, the sensor  10  may measure an amount of oil flown into a hydraulic cylinder for each driven part. In this case, the sensor  10  may output the sensing information representing an amount of oil flown into a hydraulic cylinder for each driven part of the construction machine  1 . Alternatively, the sensor  10  may measure an operating distance for each driven part of the construction machine  1 . In the case of a hydraulic excavator serving as the construction machine  1 , for example, the sensor  10  may measure the length of a rod protruded from a hydraulic cylinder for each driven part. In this case, the sensor  10  may be a stroke sensor. In addition, the sensor  10  may output the sensing information representing the operating distance for each driven part. The sensing information may be one example of feedback information. The exterior control device  2  is a device configured to control an exterior operation of the construction machine  1  from a remote place. 
       FIG.  2    is a block diagram showing the hardware configuration of the exterior control device  2 . 
     As shown in  FIG.  2   , the exterior control device  2  is a computer including various hardware elements such as a CPU (Central Processing Unit)  101 , a ROM (Read-Only Memory)  102 , a RAM (Random-Access Memory)  103 , and a communication module  104 . The exterior control device  2  is configured to execute control programs stored in advance. Accordingly, the exterior control device  2  achieves various functions as shown in  FIG.  1    serving as a filtering device  21 , an attitude calculation unit  22 , and a control unit  23 . In addition, the filtering device  21  achieves various functions serving as a noise-characteristic estimation unit  211 , a filtering adjustment unit  212 , and a filtering-processing unit  213 . Any functions among the aforementioned functions may be realized by electronic circuits. 
     The filtering device  21  is configured to acquire measurement data from the sensors  10  so as to perform a filtering process to eliminate noise superposed on measurement data. The attitude calculation unit  22  is configured to calculate attitude information including a value of a current attitude (an attitude value) of the construction machine  1  using the measurement data subjected to the filtering process. The control unit  23  is configured to control the construction machine  1  based on the attitude information of the construction machine  1  and the drive control information including a driving direction and drive speed for each driven part such as an actuator of the construction machine  1  according to a user operation or an automatic control. 
     The noise-characteristic estimation unit  211  of the filtering device  21  is configured to estimate characteristics of noise superposed on measurement data acquired from the sensors  10  based on the status information representing the status of the construction machine  1 . The status information indicates at least one of the attitude information and the drive control information. For example, it is possible to assume the estimated noise characteristics as an amount of noise in a predetermined time. The filtering adjustment unit  212  is configured to adjust the filtering to eliminate noise superposed on measurement data. For example, the filtering adjustment unit  212  may adjust parameters in a filtering calculation formula (e.g., a noise-filtering process). Alternatively, the filtering adjustment unit  212  may change the filtering calculation formula with another filtering calculation formula. The filtering processing unit  213  is configured to perform a filtering process of noise superposed on measurement data using the filtering calculation formula adjusted by the filtering adjustment unit  212 . 
     The following exemplary embodiments refer to all the controlled machines as construction machines; but controlled machines should not be necessarily limited to construction machines. For example, it is possible to assume controlled machines as physical distribution/transportation machines. Specifically, it is possible to mention forklifts, stackers, cranes, automated guided vehicles (AGV), etc. Alternatively, it is possible to assume controlled machines as other industrial machines, personal robots, marine hydraulic power units, and the like. Those controlled machines may be involved in state transitions in terms of characteristics of noise superposed on measurement data. In other words, it is possible to assume any types of controlled machines, other than the aforementioned machines, which may be involved in state transitions in terms of characteristics of noise superposed on measurement data. 
     First Exemplary Embodiment 
       FIG.  3    is a block diagram showing the functionality of the control system  100  according to the first exemplary embodiment. 
     The construction machine  1  includes an interior control unit  11 , an actuator control unit  12 , and an actuator  13 . The control system  100  further includes the sensor  10  and the exterior control device  2  similar to the foregoing ones. According to the first exemplary embodiment, the control unit  23  of the exterior control device  2  outputs the drive control information directly to the interior control unit  11  included in the construction machine  1 ; the interior control unit  11  controls the actuator control unit  12  based on the drive control information; the actuator control unit  12  drives the actuator  13  under the control of the interior control unit  11 . In the case of a hydraulic excavator serving as the construction machine  1 , for example, the actuator  13  should drive a boom, an arm, a bucket, or the like. In this connection, the interior control unit  11  may control a traveling mechanism installed in the construction machine  1 , a rotating mechanism for rotating a body of the construction machine  1  in a horizontal direction, or the like based on the drive control information. 
       FIG.  4    is a flowchart showing the processing of the exterior control device  2  according to the first exemplary embodiment. 
     Hereinafter, the processing of the control system  100  will be described in detail. 
     The sensors  10  are outputting their measurement data to the exterior control device  2  while the construction machine  1  is operating based on the drive control information output from the exterior control device  2 . For example, the sensors  10  communicate with the exterior control device  2  via wired communication so as to transmit wires signals including measurement data to the exterior control device  2 . In this connection, the sensors  10  may communicate with the exterior control device  2  via wireless communication so as to transmit wireless signals including measurement data to the exterior control device  2 . The exterior control device  2  acquires measurement data (step S 101 ). 
     The filtering processing unit  213  performs a filtering process to eliminate noise from the acquired measurement data using a filtering calculation formula adjusted by the filtering adjustment unit  212  (step S 102 ). The attitude calculation unit  22  calculates a current attitude value, serving as an example of the current status of the construction machine  1  using the measurement data from which noise has been eliminated in the filtering process (step S 103 ). The attitude value of the construction machine  1  represents an angle relative to the reference position for each driven part. For example, as described above, the attitude value may represent a rotation angle of a boom, an arm, or a bucket in its reference direction. 
     The control unit  23  acquires a current attitude value from the attitude information of the attitude calculation unit  22 . In addition, the control unit  23  acquires a target attitude value which is determined according to a user operation or an automatic control (step S 104 ). The control unit  23  generates the drive control information based on the current attitude value and the target attitude value (step S 105 ). The drive control information may include data components representing drive speed and a driving direction for each driven part such as an actuator. In this connection, the drive control information may include a data component representing a drive type of the construction machine  1 . For example, the drive type represents a type of work of the construction machine  1 , or the drive type represents any types such as excavation, lifting, leveling, rotation, forward traveling, and backward traveling of the construction machine  1  serving as a hydraulic shovel. The control unit  23  generates and outputs the drive control information to the construction machine  1  (step S 106 ). 
     The interior control unit  11  of the construction machine  1  acquires the drive control information. The interior control unit  11  converts the drive control information into prescribed signals which can be acknowledged by the actuator control unit  12 , thus outputting prescribed signals to the actuator control unit  12 . The actuator control unit  12  controls the actuator  13  based on prescribed signals output from the interior control unit  11 . Thus, the construction machine  1  can operate based on the drive control information. 
     The attitude calculation unit  22  outputs attitude values corresponding to measurement data output from the sensors  10  to the noise-characteristic estimation  211 . In addition, the control unit  23  outputs the drive control information to the construction machine  1  as well as the noise-characteristic estimation unit  211 . The noise-characteristic estimation unit  211  estimates characteristics of noise superposed on measurement data using the drive control information and the attitude value representing the current attitude of the construction machine  1  (step S 107 ). 
     Specifically, the exterior control device  2  stores a noise-characteristic estimation table on a storage unit installed therein. For example, the noise-characteristic estimation table is a data table configured to store noise characteristics in association with the attitude value of the construction machine  1  and the drive type of the construction machine  1 . In the present exemplary embodiment, as described above, the attitude value of the construction machine  1  represents a rotation angle for each driven part in its reference direction. Herein, noise characteristics which are recorded on the noise-characteristic estimation table in association with the attitude value and the drive type might be previously measured values which have been previously measured in previous measurements, for example, wherein it is possible to record statistic values such as noise variances upon defining noise as a difference between an attitude value, which is calculated from measurement data obtained from the sensors  10  in the predetermined time, and a correct value for each attitude when the construction machine  1  is fixed to a certain attitude or when the construction machine  1  is driven to change its attitude from one attitude to another attitude. The correct value for each attitude would be an accurately-measured value for each attitude of each driven part of the construction machine  1  using a measuring instrument such as a total station. The noise-characteristic estimation unit  211  estimates characteristics of noise superposed on measurement data by selecting the current noise characteristics from the noise-characteristic estimation table according to the acquired attitude value and the drive type included in the acquired drive control information. The noise-characteristic estimation unit  211  outputs the selected noise characteristics to the filtering adjustment unit  212 . 
     In this connection, the noise-characteristic estimation unit  211  may estimate noise characteristics by another method. For example, the noise-characteristic estimation unit  212  may estimate noise characteristics based on the attitude value of the construction machine  1  alone. In this case, for example, the noise-characteristic estimation table would be a data table configured to store noise characteristics associated with the attitude value of the construction machine  1  in advance. The noise-characteristic estimation unit  211  estimates characteristics of noise superposed on measurement data by selecting the current noise characteristics from the noise-characteristic estimation table based on the acquired attitude value. 
     Alternatively, the noise-characteristic estimation unit  211  may estimate noise characteristics based on the drive type of the construction machine  1  alone. In this case, for example, the noise-characteristic estimation table would be a data table configured to store noise characteristics associated with the drive type of the construction machine  1  in advance. The noise-characteristic estimation unit  211  estimates characteristics of noise superposed on measurement data by selectin the current noise characteristics from the noise-characteristic estimation table according to the drive type included in the acquired drive control information. 
     The aforementioned process of the noise-characteristic estimation unit  211  would be one aspect of a process to select noise characteristics associated with a value of status information according to an association between the value of the status information and noise characteristics. 
     The noise-characteristic estimation unit  211  may estimate noise characteristics based on the drive content for each driven part of the construction machine  1 . In this case, for example, the noise-characteristic estimation table would be a data table configured to store noise characteristics for each driven part of the construction machine  1  according to its drive content in advance. The drive content represents drive speed and a driving direction for each driven part. In this connection, the drive speed may represent an amount of movement for each driven part per unit time. Herein, the noise-characteristic estimation table records previously measured values, which have been measured in previous measurements in advance, as noise characteristics according to the drive content for each driven part, for example, wherein it is possible to store statistic values as noise variances upon defining noise as a difference between an attitude value, which is calculated from measurement data obtained from the sensors  10  in the predetermined time, and a correct value for each attitude of each driven parts being driven when each driven part of the construction machine  1  is driven at certain drive speed in a certain driving direction while changing its attitude from one attitude to another attitude. The noise-characteristic estimation unit  211  estimates characteristics of noise superposed on measurement data by selecting the current noise characteristics from the noise-characteristic estimation table according to the drive content included in the acquired drive control information. 
     Moreover, the noise-characteristic estimation unit  211  may estimate noise characteristics according to inertia force applied to each driven part of the construction machine  1 . For example, the following description refers to an incline sensor serving as the sensor  10 . While a hydraulic shovel is operating, motion acceleration such as centrifugal force other than gravity should be imparted to force applied to each driven part of the construction machine  1 . Since the incline sensor cannot detect gravity acceleration separately from other motion acceleration, the incline sensor should detect motion acceleration as resultant force between gravity acceleration and other motion acceleration. That is, the sensor  10  should measure an incline and an angle for each driven part in a resultant direction of gravity corresponding to resultant force between gravity acceleration and other motion acceleration, indicating appearance of an error (noise) as a difference in acceleration between the resultant direction of gravity and an actual direction of gravity. For this reason, it is possible to eliminate such an error (noise) by calculating a difference between motion acceleration, such as centrifugal force other than gravity acceleration, and acceleration in a direction of gravity. In the case of an incline sensor having a single axis, for example, it is possible to calculate an incline (or an angle) for each driven part via formula (1). In formula (1), a symbol θ represents an incline (or an angle) for each driven part; a symbol F represents gravity acceleration detected by an incline sensor; a symbol G represents gravity acceleration. Upon assuming an operating state of a hydraulic shovel, F should be a resultant force combining gravity acceleration and motion acceleration such as centrifugal force. In this connection, it is possible to transform formula (1) into formula (2) using F(G) as gravity acceleration and F(A) as other motion acceleration among various values of gravity acceleration detected by an incline sensor. It is possible to realize formula (3) upon finding F(G) as gravity acceleration from formula (2). Using F(G) as gravity acceleration determined in formula (2), it is possible to realize formula (4) upon finding an actual incline (or an angle θ′) for each driven part. 
       [Math 1] 
       θ=arcsin( F/G )  (1)
 
       [Math 2] 
       θ=arcsin(( F ( G )− F ( A ))/ G ))  (2)
 
       [Math 3] 
         F ( G )= G ·sin(θ)+ F ( A )  (3)
 
       [Math 4] 
       θ′=arcsin( F ( C )/ G )  (4)
 
     Assuming other motion acceleration F(A) as centrifugal force, it is possible to calculate other motion acceleration F(A) via formula (5). Herein, a symbol m represents a mass of an incline sensor; a symbol co represents angular speed of an inclination sensor; a symbol r represents a distance from an incline sensor to a rotation axis for each driven part; a symbol ϕ represents an angle calculated between centrifugal force and a reference direction of an incline sensor. In this connection, it is possible to calculate angular speed of an incline sensor according to the attitude information recently calculated by the attitude calculation unit  22 . 
       [Math 5] 
         F ( A )= mω   2   r ·sin(ϕ)  (5)
 
     As to other motion acceleration F(A), it is possible to calculate a traveling distance per unit time in a detection direction of an incline sensor based on the recent attitude information as a variation of motion acceleration F(A). Alternatively, it is possible to produce motion acceleration F(A) according to motion of inertia and natural frequency. 
     Upon estimating noise characteristics, the noise-characteristic estimation unit  211  output the noise characteristics to the filtering adjustment unit  212 . The processing of the noise-characteristic would be one aspect of processing for estimating noise characteristics based on analysis results about the status of a controlled machine (e.g., force of inertia, moment of inertia, natural frequency) which is calculated based on the status information. In this connection, the noise-characteristic estimation unit  211  may estimate noise characteristics using any one of the aforementioned processes individually with respect to multiple measurement data acquired from the sensors  10 . In this case, the noise-characteristic estimation unit  211  may outputs to the filtering adjustment unit  212  the information relating to a combination of an identifier of the sensor  10  assigned to its measurement data and its corresponding noise characteristics. 
     Based on the estimated noise characteristics, the filtering adjustment unit  212  adjusts a formula of filtering to eliminate noise from measurement data to a filtering formula to appropriately eliminate noise from measurement data when the construction machine  1  maintains its current attitude or drives its specific part (step S 108 ). 
     When a Kalman filter is used to perform a filtering process for noise elimination, for example, the filtering adjustment unit  212  may correct a variance σ v   2  of system noise and a variance σ w   2  of observation noise of a Kalman filter based on the estimated noise characteristics. Specifically, the filtering adjustment unit  212  should correct a variance σ v   2  of system noise in a prior-error covariance matrix P − (k) based on the estimated noise characteristics in a prediction step according to formula (6). Alternatively, the filtering adjustment unit  212  should correct a variance σ w   2  of observation noise in a Kalman gain based on the estimated noise characteristics in a filtering step according to formula (7). 
       [Math 6] 
         P ( k )= A·P ( k− 1)· A   T +σ v   2   b·b   T   (6)
 
       [Math 7] 
         g ( k )= P   − ( k )· c/{c   T   ·P   − ( k )· c+σ   w   2 }  (7)
 
     Instead of the process of step S 108 , the filtering adjustment unit  212  may change a filtering type based on the estimated noise characteristics. For example, the filtering adjustment unit  212  may select an appropriate filtering method suited to the estimated noise characteristics among multiple filtering methods such as a Kalman filter and an infinite impulse response (IIR) filter. The filtering adjustment unit  212  determines and outputs the filtering method to the filtering processing unit  213 . 
     Using the filtering method, the filtering processing unit  213  performs a filtering process of noise superposed on measurement data acquired from the sensor(s)  10 . 
     The exterior control device  2  may repeatedly perform a series of the aforementioned processes of steps S 101  through S 108 . In this connection, the exterior control device  2  may successively or periodically repeat the aforementioned processes. For example, the exterior control device  2  may periodically perform the aforementioned processes according to a cycle of the sensor(s)  10  to output measurement data. 
     Alternatively, the exterior control device  2  may starts the aforementioned processes from the process of step S 101  at the timing to receive measurement data from the sensor  10 . 
     Due to implementation of the aforementioned processes in step S 101  through S 108 , the filtering device  21  can adjust filtering to appropriately eliminate noise superposed on measurement data according to the attitude and the driven status of the construction machine  1 . As a result, the external control device  2  can eliminate noise (i.e., noise superposed on measurement data) which may be varied according to the attitude and the driven status of the construction machine  1  with high accuracy; hence, it is possible to improve precision of controlling the attitude and the driven status of the construction machine  1 . 
     Second Exemplary Embodiment 
       FIG.  5    is a block diagram showing the functionality of the control system  100  according to the second exemplary embodiment. 
     The control system  100  of the second exemplary embodiment differs from the control system  100  of the first exemplary embodiment in that the exterior control device  2  outputs the drive control information to a robot  3  configured to operate the construction machine  1 . 
     In this case, the construction machine  1  includes the actuator control unit  12  and the actuator  13  as well as an operator  14  such as an operation lever and an operation pedal. The robot (or an attachment)  3  is configured to operate the operator  14  of the construction machine  1  based on the drive control information of the construction machine  1  obtained from the exterior control device  2 . In this case, the robot (or the attachment)  3  is located close to the operator  14  in order to operate the operator  14 . 
     In the second exemplary embodiment, the operation of the exterior control device  2  is similar to that of the first exemplary embodiment. Based on the drive control information of the construction machine  1 , the robot (or the attachment)  3  should operate the operator  14  of the construction machine  1  to achieve an operation of the actuator  13  according to the drive control information. The actuator control unit  12  acquires an output signal to be output due to an operation of the operator  14  so as to control the actuator based on the output signal. Accordingly, it is possible for the construction machine  1  to perform an operation based on the drive control information. 
     Third Exemplary Embodiment 
       FIG.  6    is a block diagram showing a filtering system including a filtering device according to the third exemplary embodiment. 
       FIG.  7    is a flowchart showing the processing of the filtering device according to the third exemplary embodiment. 
     The filtering system includes the sensor  10  and the filtering device  21 . The filtering device  21  includes at least the noise-characteristic estimation unit  211  and the filtering adjustment unit  212 . 
     The sensor  10  is configured to acquire measurement data relating to the status of a controlled machine. 
     The noise-characteristic estimation unit  211  is configured to estimate characteristics of noise superposed on measurement data based on the status information representing the status of a controlled machine (step S 701 ). 
     The filtering adjustment unit  212  is configured to adjust filtering to eliminate noise based on the estimated noise characteristics (step S 702 ). 
     The aforementioned devices include computer systems therein. The aforementioned processes are stored on computer-readable storage media in the form of programs; hence, computer may read and execute programs to achieve the aforementioned processes. Herein, computer-readable storage media refer to magnetic disks, magneto-optical disks, CD-ROM, DVD-ROM, semiconductor memory, and the like. In addition, it is possible to deliver computer programs to computers, hence, computers may receive and execute programs delivered thereto. 
     The aforementioned programs may achieve some of the aforementioned functions. In addition, the aforementioned programs may be so-called differential files (or differential programs) which can be combined with pre-installed programs of computer systems to achieve the aforementioned functions. 
     Part or the entirety of the foregoing embodiments can be expressed as the following appendixes, however, which are not necessarily restrictive. 
     APPENDIX 1 
     A program causing a computer of a filtering device to implement functions as a noise-characteristic estimation means configured to estimate characteristics of noise superposed on measurement data relating to a status of a controlled machine based on status information representing the status of the controlled machine, and a filtering adjustment means configured to adjust filtering to eliminate the noise based on the estimated noise characteristics. 
     APPENDIX 2 
     The program according to Appendix 1, wherein the noise-characteristic estimation means estimates noise characteristics suited to a value of the status information according to an association between the value of the status information and the noise characteristics. 
     APPENDIX 3 
     The program according to Appendix 1, wherein the noise-characteristic estimation means estimates noise characteristics according to an analysis result about the status of the controlled machine which is calculated based on the value of the status information. 
     APPENDIX 4 
     The program according to any one of Appendix 1 through Appendix 3, wherein the filtering adjustment means adjusts a variance of a Kalman filter according to noise characteristic. 
     APPENDIX 5 
     The program according to any one of Appendix 1 through Appendix 3, wherein the filtering adjustment means adjusts a formula of filtering to a filtering formula to eliminate the noise according to noise characteristics, thus eliminating the noise according to the adjusted filtering formula. 
     APPENDIX 6 
     The program according to any one of Appendix 1 through Appendix 5, wherein the filtering adjustment means identifies a filtering formula suited to noise characteristics among a plurality of different filtering formulae, thus eliminating noise according to the identified filtering formula. 
     APPENDIX 7 
     The program according to any one of Appendix 1 through Appendix 6, wherein the status information includes at least one of attitude information representing the attitude of the controlled machine and drive control information representing an instruction to drive the controlled machine. 
     REFERENCE SIGNS LIST 
     
         
           1  . . . construction machine 
           2  . . . exterior control device 
           3  . . . robot 
           10  . . . sensor 
           21  . . . filtering device 
           22  . . . attitude calculation unit 
           23  . . . control unit 
           211  . . . noise-characteristic estimation unit 
           212  . . . filtering adjustment unit 
           213  . . . filtering processing unit