Source: http://www.google.com/patents/US6877837?ie=ISO-8859-1
Timestamp: 2014-11-27 01:46:17
Document Index: 778156984

Matched Legal Cases: ['art 11', 'art 11', 'art 6', 'art 93', 'art 93', 'art 84', 'art 91', 'art 91', 'art 84', 'art 91', 'art 94', 'art 84', 'art 93', 'art 83', 'art 95', 'art 91', 'art 95', 'art 91', 'art 91', 'art 91', 'art 95', 'art 91', 'art 91', 'art 95', 'art 91', 'art 93', 'art 84', 'art 91', 'art 95', 'art 93', 'art 94', 'art 95']

Patent US6877837 - Control unit and method for controlling motor for use in printer, and ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThere is provided a control unit capable of rapid and precise stoppage of an object to be driven by a motor for use in a printer. The control unit has a speed control part to control the object by acceleration control, constant speed control, deceleration control, and stoppage control by controlling...http://www.google.com/patents/US6877837?utm_source=gb-gplus-sharePatent US6877837 - Control unit and method for controlling motor for use in printer, and storage medium storing control programAdvanced Patent SearchPublication numberUS6877837 B1Publication typeGrantApplication numberUS 09/667,300Publication dateApr 12, 2005Filing dateSep 25, 2000Priority dateSep 28, 1999Fee statusPaidAlso published asDE60024746D1, DE60024746T2, EP1088674A1, EP1088674B1, US7147299, US20050146555Publication number09667300, 667300, US 6877837 B1, US 6877837B1, US-B1-6877837, US6877837 B1, US6877837B1InventorsHitoshi Igarashi, Masanori YoshidaOriginal AssigneeSeiko Epson CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (8), Referenced by (4), Classifications (18), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetControl unit and method for controlling motor for use in printer, and storage medium storing control programUS 6877837 B1Abstract There is provided a control unit capable of rapid and precise stoppage of an object to be driven by a motor for use in a printer. The control unit has a speed control part to control the object by acceleration control, constant speed control, deceleration control, and stoppage control by controlling a current to be applied to the motor, and also an inertia calculating part to calculate inertia of the object based on angular acceleration of the motor under the acceleration control of the object, and current values to be applied to the motor under the acceleration control and the constant speed control of the object. The speed control part uses the calculated inertia for controlling the current to be applied to the motor.
1. A control unit for controlling a motor for use in a printer, comprising:
a speed control part to control an object to be controlled that is driven by the motor by acceleration control, constant speed control, deceleration control, and stoppage control by controlling a current to be applied to the motor; an inertia calculating part to calculate inertia of the object based on angular acceleration of the motor under the acceleration control of the object, and current values to be applied to the motor under the acceleration control and the constant speed control of the object, the calculated inertia being used by the speed control part for controlling the current to be applied to the motor; and, a stoppage current calculating part to calculate a stoppage current to be used for stopping the object at a target position based on the calculated inertia, an angular velocity of the motor under the deceleration control of the object, the current value of the motor under the constant speed control of the object, and a stoppage constant TBRK, the speed control part performing control of stopping the object by applying the calculated stoppage current, wherein a predetermined current value Iacc is applied to the motor in a constant current acceleration range under the acceleration control for accelerating the object, the inertia calculation part calculating angular acceleration Δω/Δt in the constant current acceleration range, and calculating inertia J of the object based on the angular acceleration Δω/Δt, a current value If to be applied to the motor under the constant speed control of the object, and the current value Iacc. 2. A computer-readable storage medium storing control program code for controlling a motor for use in a printer, comprising:
first program code means for calculating inertia of a carriage based on angular acceleration of a carriage motor under acceleration control of the carriage and current values to be applied to the carriage motor under the acceleration control and constant speed control of the carriage; second program code means for calculating a stoppage current to be used for stopping the carriage at a target position based on the calculated inertia, an angular velocity of the motor under deceleration control of the carriage, the current value to be applied to the motor under the constant speed control of the carriage, and a stoppage constant TBRK; and third program code means for stopping the carriage by applying the calculated stoppage current to the motor. 3. A control unit for controlling a carriage motor for use in a printer, comprising:
a speed control part to control a carriage to be controlled that is driven by the motor by acceleration control, constant speed control, deceleration control, and stoppage control by controlling a current to be applied to the motor; an inertia calculating part to calculate inertia of the carriage based on angular acceleration of the motor under the acceleration control of the carriage, and current values to be applied to the motor under the acceleration control and the constant speed control of the carriage, the calculated inertia being used by the speed control part for controlling the current to be applied to the motor; and a stoppage current calculating part to calculate a stoppage current to be used for stopping the carriage at a target position based on the calculated inertia, an angular velocity of the motor under the deceleration control of the carriage, the current value of the motor under the constant speed control of the carriage, and a stoppage constant TBRK, the speed control part performing control of stopping the carriage by applying the calculated stoppage current. 4. A control unit for controlling a carriage motor for use in a printer, as set forth in claim 3 wherein a predetermined current value Iacc is applied to the motor in a constant current acceleration range under the acceleration control for accelerating the carriage, the inertia calculation part calculating angular acceleration Δω/Δt in the constant current acceleration range, and calculating inertia J of the carriage based on the angular acceleration Δω/Δt, a current value If to be applied to the motor under the constant speed control of the carriage, and the current value Iacc.
5. A method of controlling a carriage motor for use in a printer, comprising:
calculating inertia of a carriage to be driven by the motor based on angular acceleration of the motor under acceleration control of the carriage and current values to be applied to the motor under the acceleration control and a constant speed control of the carriage; and controlling a current to be applied to the motor by means of the calculated inertia, wherein the controlling of the current comprises: calculating a stoppage current to be used for stopping the carriage at a target position based on the calculated inertia, an angular velocity of the motor under deceleration control of the carriage, the current value of the motor under the constant speed control of the carriage, and a stoppage constant TBRK; and stopping the carriage by applying the calculated stoppage current to the motor. 6. A method of controlling a carriage motor for use in a printer, as set forth in claim 5, wherein the printer is a serial printer.
a speed control part to control an object to be controlled that is driven by the motor by acceleration control, constant speed control, deceleration control, and stoppage control by controlling a current to be applied to the motor; and an inertia calculating part to calculate inertia of the object based on angular acceleration of the motor under the deceleration control of the object, and current values to be applied to the motor under the deceleration control and the constant speed control of the object, during the deceleration control after a printing processing is completed, the calculated inertia being used by the speed control part for controlling the current to be applied to the motor. 8. A control unit for controlling a motor for use in a printer, as set forth in claim 7, further comprising a stoppage current calculating part to calculate a stoppage current to be used for stopping the object at a target position based on the calculated inertia, an angular velocity of the motor under the deceleration control of the object, the current value of the motor under the constant speed control of the object, and a stoppage constant TBRK, the speed control part performing control of stopping the object by applying the calculated stoppage current.
calculating inertia of an object to be driven by the motor based on angular acceleration of the motor under deceleration control of the object, and current values to be applied to the motor under acceleration control and a constant speed control of the object, during the deceleration control after a printing processing is completed; and controlling a current to be applied to the motor by means of the calculated inertia. 16. A method of controlling a motor for use in a printer, as set forth in claim 15, wherein the controlling of the current includes:
calculating a stoppage current to be used for stopping the object at a target position based on the calculated inertia, an angular velocity of the motor under the deceleration control of the object, the current value of the motor under the constant speed control of the object, and a stoppage constant TBRK; and stopping the object by applying the calculated stoppage current to the motor. 17. A method of controlling a motor for use in a printer, as set forth in claim 15, wherein the object is a carriage of a serial printer.
18. A computer readable storage medium storing control program code for controlling a motor for use in a printer, comprising:
first program code means for calculating inertia of a carriage based on angular acceleration of a carriage motor under deceleration control of the carriage and current values to be applied to the carriage motor under acceleration control and constant speed control of the carriage, during the deceleration control after a printing processing is completed; second program code means for calculating a stoppage current to be used for stopping the carriage at a target position based on the calculated inertia, an angular velocity of the motor under deceleration control of the carriage, the current value to be applied to the motor under the constant speed control of the carriage, and a stoppage constant TBRK; and third program code means for stopping the carriage by applying the calculated stoppage current to the motor.
The stoppage constant TBRK may be decided based on the current value to be applied to the motor under the constant speed control and a positional deviation of an actual position of the motor from the target position.
FIGS. 3(a) and 3(b) are waveform illustrations of the embodiment shown in FIG. 1;
FIGS. 7(a) and 7(b) are waveform illustrations of output pulses of an encoder;
Then, the construction of the linear type encoder 11 mounted on the carriage 3 is shown in FIG. 6. This encoder 11 comprises a light emitting diode 11 a, a collimator lens 11 b, and a detection processing part 11 c. The detection processing part 11 c has a plurality of (four) photodiodes 11 d, a signal processing circuit 11 e, and two comparators 11 f A and 11 f 8.
If a voltage Vcc is applied between both ends of the light emitting diode 11 a via a resistor, light rays are emitted from the light emitting diode 11 a. The light rays are collimated by the collimator lens 11 b to pass through the code plate 12. The code plate 12 is provided with slits at regular intervals (e.g., every {fraction (1/180)} inches (={fraction (1/180)}�2.54 cm)).
The parallel rays passing through the code plate 12 are incident on each of the photodiodes 11 d via a fixed slit (not shown), and converted into electric signals. The electric signals outputted from the four photodiodes 11 d are processed by the signal processing circuit 11 e. The signals outputted from the signal processing circuit 11 e are compared by the comparators llfA and llfB, and the compared results are outputted as pulses. The pulses ENC-A and ENC-B outputted from the comparators 11fA and 11 f B are outputs of the encoder 11.
The phase of the pulse ENC-A is different from the phase of the pulse ENC-B by 90 degrees. The encoder 4 is designed so that the phase of the pulse ENC-A is advanced from the pulse ENC-B by 90 degrees as shown in FIG. 7(a) when the CR motor 4 is normally rotating, i.e., when the carriage 3 is moving a main scanning direction, and the phase of the pulse ENC-A lags behind the pulse ENC-B by 90 degrees as shown in FIG. 7(b) when the CR motor 4 is reversely rotating. One period T of the pulses corresponds to the distance between adjacent slits of the code plate 12 (e.g., {fraction (1/180)} inches (={fraction (1/180)}�2.54 cm)). This is equal to a period of time, in which the carriage 3 moves between the adjacent slits.
On the other hand, the rotary type encoder 13 for use in the PF motor 1 has the same construction as that of the linear type encoder 11, except that the code plate is a rotating disk which rotates in accordance with the rotation of the PF motor 1. Furthermore, in the ink jet printer, the distance between adjacent slits of a plurality of slits provided in the code plate of the encoder 13 for use in the PF motor is {fraction (1/180)} inches ({fraction (1/180)}�2.54 cm). When the PF motor 1 rotates by the distance between adjacent slits, the paper is fed by {fraction (1/1440)} inches (={fraction (1/1440)}�2.54 cm).
In FIG. 8, the paper 50 inserted into a paper feeding port 61 of a printer 60 is fed into the printer 60 is fed into the printer 60 by means of a paper feeding roller 64 which is driven by a paper feeding motor 63. The front edge of the paper 50, which has been fed into the printer 60, is detected by, e.g., an optical paper detecting sensor 15. The paper 50, the front edge of which has been detected by the paper detecting sensor 15, is fed of which has been detected by the paper detecting sensor 15, is fed by means of a paper detecting by the paper detecting sensor 15, is fed by means of a paper feed roller 65 and a driven roller 66 which are driven by the PF motor 1.
The position calculating part 6 a is designed to detect the leading and trailing edges of each of the output pulses ENC-A and ENC-B of the encoder 11 to count the number of the detected edges, and to calculate the position of the carriage 3 on the basis of the counted value. In this counting, when the CR motor 4 is normally rotating, if one edge is detected, �+1� is added, and when the CR motor 4 is reversely rotating, if one edge is detected, �−1� is added. Each of the periods of the pulses ENC-A and ENC-B is equal to the distance between adjacent slits of the code plate 12, and the phase of the pulse ENC-A is different from the phase of the pulse ENC-B by 90 degrees. Therefore, the counted value �−1� in the above described counting corresponds to � of the distance between adjacent slits of the code plate 12. Thus, if the counted value is multiplied by � of the distance between adjacent slits, it is possible to obtain the moving amount of the carriage 3 from a position corresponding to a counted value �0�. At this time, the definition of the encoder 11 is � of the distance between adjacent slits of the code plate 12. If the distance between adjacent slits is {fraction (1/180)} inches (={fraction (1/180)}�2.54 cm), the definition is {fraction (1/720)} inches (={fraction (1/720)}�2.54 cm).
As shown in FIG. 2, the inertia calculating part 93 has, for example, a memory 93 a, timer 93 b and a calculator 93 c. The inertia calculating part 93 calculates inertia J (including inertia of an ink cartridge) of the carriage 3 based on the output of the period measuring part 84, the output of the acceleration control part 91, and also the output of the integrating element 87 b. After receiving the command signal from the acceleration control part 91, the memory 93 a stores the second period T2 and the K-th period TX (K≧3) fed from the period measuring part 84. The periods T2 and TX are the values while the acceleration control part 91 is outputting the predetermined value Iacc. The subscript K is predetermined according to control.
The timer 93 b counts a period of time Tt from reception of the second period T2 to the K-th period TX. Instead of counting, a period Ti (i=2, . . . , K) from the second to the K-th can be integrated as
Tt=T3+. . . +Tk. The calculator 93 c calculates the inertia J of the carriage 3 according to the equation (1) based on the values Iacc, T2, TX and Tt, and also an output If of the integrating element 87 b, which is the output just before the moment the carriage 3, or the CR motor 4 is in transition from the constant speed range to the deceleration range. J = ⁢ I acc - I f Δω Δ ⁢ ⁢ t = ⁢ I acc - I f { ( α T κ - α T 2 ) ( T 2 + T s ) } ( 1 ) In the equation (1), ω and α represent an angular velocity of the CR motor 4 and a constant for obtaining the angular velocity, respectively, the numerator indicates subtraction of a friction component If from a torque (a drive current Icc), and the denominator indicates the rate of change in angular velocity of the CR motor 4, or angular acceleration.
The stoppage current calculating part 94 calculates a current value ISTOP to be applied to the CR motor 4 for stopping the carriage at the target position according to the equation (2) based on the output Tf of the period measuring part 84, the output If of the integrating element 87 b in transition from the constant speed to deceleration ranges, the output of the subtracter 82, and also the output J of the inertia calculating part 93 when the output of the subtracter 86 is decreased to a predetermined value or less while the target speed calculating part 83 is outputting a predetermined value Vs. I stop = I f - α T f T BRK ⁢ J ( 2 ) The resultant current value ISTOP is supplied to the selection part 95.
Referring to FIGS. 3(a) and 3(b), the operation of the controller 80 will be described below.
If a start-up command signal for starting the CR motor 4 is fed from the CPU 16 to the controller 80 of the DC unit 6 when the CR motor 4 is stopped, a start-up initial current value Io is fed from the acceleration control part 91 to the D/A converter 96 via the selection part 95. Furthermore, this start-up initial current value Io, together with the start-up command signal, is fed from the CPU 16 to the acceleration control part 91. Then, this current value Io is converted into an analog current by the D/A converter 96 to be fed to the driver 5, and the CR motor is started up by the driver 5 (see FIGS. 3(a), 3(b)).
After the start-up command signal is received, the timer 90 generates a timer interruption signal for every predetermined time. Every time the acceleration control part 91 receives the timer interruption signal, the acceleration control part 91 integrates a predetermined current value (e.g., 20 mA) into the start-up initial current value Io, to feed the integrated current value to the D/A converter 96 via the selection part 95. Then, the integrated current value is converted into an analog current by the D/A converter 96 to be fed to the driver 5. Then, the CR motor is driven by the driver 5 so that the value of the current supplied to the CR motor 4 is the integrated current value, so that the speed of the CR motor 4 increases (see FIG. 3(b)). Therefore, the current value supplied to the CR motor is step-wise as shown in FIG. 3(a).
The integration of the current value in the acceleration control part 91 is carried out until the speed of the CR motor 4 reaches a speed V0. When a current value integrated at time t1 reaches the predetermined value Iacc, the acceleration control part 91 halts the integration operation, and feeds the constant current value Iacc to the D/A converter 96 via the selection part 95 so that the driver 5 drives the CR motor 4 with the current value Iacc applied thereto (see FIG. 3(a)). During this process, the acceleration control part 91 sends a command signal to the inertia calculating part 93. After receiving the command signal, the memory 93 a stores the second period T2 and the K-th period TK (K≧3) fed from the period measuring part 84. The timer 93 b measures a period of time Tt from the reception of the second period T2 to the K-th period TX.
Then, in order to prevent the speed of the CR motor 4 from overshooting, the acceleration control part 91 controls the CR motor 4 so as to reduce the current, which is supplied to the CR motor 4, when the speed of the CR motor 4 becomes a predetermined speed V1 (see time t2). At this time, the speed of the CR motor 4 further increases. However, when the speed of the CR motor 4 reaches a predetermined speed Vc (see time t, in FIG. 3(b)), the selection part 95 selects the output of the PID control system, i.e., the output of the adder 89, to carry out the PID control.
That is, the target speed is calculated on the basis of the position deviation of the actual position, which is obtained from the output of the encoder 11, from the target position. In addition, the proportional element 87 a, integrating element 87 b and differentiating element 87 c are operated on the basis of the speed deviation of the actual speed, which is obtained from the output of the encoder 11, from the target speed to carry out the proportional, integrating and differentiating operations. Moreover, the CR motor 4 is controlled on the basis of the sum of these calculated results. Furthermore, the above described proportional, integrating and differentiating operations are carried out in synchronism with, e.g., the leading edge of the output pulse ENC-A of the encoder 11. Thus, the speed of the DC motor 4 is controlled so as to be a desired speed Vs. Furthermore, the predetermined speed Vc is preferably a value of 70% to 80% of the desired speed Vs.
Since the speed of the DC motor 4 is the desired speed Vs after time t4, a printing processing can be carried out. When the printing processing is completed and when the carriage 3 reaches the target position (see time t, in FIG. 3(b)), deceleration control is performed by PID control system. Moreover, the output If of the integration element 87 b just before the deceleration control is fed to the inertia calculating part 93 for calculation of the inertia J of the carriage 3 having the rotary section of the CR motor 4.
When the deviation of an actual speed from the predetermined value Vs reaches a predetermined value or less (see time t6), the stoppage current calculating part 94 calculates the current value ISTOP to be applied to the CR motor 4 according to the equation (2) for stopping the carriage at the target position. The current value ISTOP is fed to the D/A converter 96 via the selection part 95 so that the driver 5 drives the CR motor 4 with the current value ISTOP to stop the CR motor 4, or the carriage 3 at the target position (see time t7 in FIG. 3(b)).
Calculated next is a stoppage current for stopping the carriage 3 at the target position based on the calculated inertia, an angular velocity of the CR motor 4 at carriage deceleration, a current value applied to the CR motor 4 under carriage constant control, and the stoppage constant TBRK, (see step F2 in FIG. 9).
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3931562Jul 23, 1974Jan 6, 1976U.S. Philips CorporationElectric driving arrangement using a stepping motorUS4558265 *Mar 2, 1983Dec 10, 1985Hitachi, Ltd.Method and apparatus for position control of an electric motorUS5159254 *Apr 9, 1991Oct 27, 1992Mitsubishi Denki K.K.Numerical control unit for estimating movement parameters using a modelUS5871291Jun 2, 1995Feb 16, 1999Canon Kabushiki KaishaRecording apparatus, method and information-processing systemEP0659572A2Dec 22, 1994Jun 28, 1995Seiko Epson CorporationPrinter and method of controlling itJPH0278557A Title not availableJPH1120143A Title not availableJPS5612898A Title not available* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6998812 *Aug 8, 2003Feb 14, 2006Dr. Johannes Heidenhain GmbhMethod for determining the mass moment of inertia of an electric motor drive systemUS7078875 *Oct 28, 2004Jul 18, 2006Canon Kabushiki KaishaDC motor control apparatus and recording apparatusUS7176649May 17, 2006Feb 13, 2007Canon Kabushiki KaishaDC motor control apparatus and recording apparatusUS7862246 *Mar 25, 2006Jan 4, 2011Brother Kogyo Kabushiki KaishaPower supply controller for motor in feeding device* Cited by examinerClassifications U.S. Classification347/37, 318/626, 318/648, 318/616, 400/283International ClassificationH02P7/29, H02P7/06, G05B19/416, B41J19/20, B41J19/18Cooperative ClassificationB41J19/202, G05B2219/43006, G05B2219/43016, G05B2219/45187, G05B2219/37388, G05B19/4163European ClassificationG05B19/416A, B41J19/20BLegal EventsDateCodeEventDescriptionSep 12, 2012FPAYFee paymentYear of fee payment: 8Sep 22, 2008FPAYFee paymentYear of fee payment: 4Nov 20, 2000ASAssignmentOwner name: SEIKO EPSON CORPORATION, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:IGARASHI, HITOSHI;YOSHIDA, MASANORI;REEL/FRAME:011256/0247Effective date: 20001018Owner name: SEIKO EPSON CORPORATION SHINJUKU-KU 4-1 NISHI-SHINFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:IGARASHI, HITOSHI /AR;REEL/FRAME:011256/0247RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google