JP2019047722A - Motor drive device and motor drive method - Google Patents

Abstract

To hinder reverse rotation movement of a motor in a case where vibration occurs due disturbance and so on, by allowing generation of a drive waveform less in terms of reaction delay, in a motor drive device that forms an efficient drive waveform on the basis of a rotation detecting position.SOLUTION: A motor drive device detects a rotating position of a rotor and an Apos generating section 301 and a Bpos generating section 302 perform a position encoding process. A drive waveform phase determining section 303 determines a drive-waveform phase to a motor. According to a signal generated by a PWM generator 112, a rotating-position phase and the drive-waveform phase are synchronously controlled. During the synchronization, a phase-difference setting process is performed for holding a predetermined phase difference between the rotating-position phase and the drive-waveform phase. In a case where the direction in which the detected rotating direction changes and a set rotating direction do not match, control for hindering reverse rotation to the set rotation is exerted according to setting by a rotating-direction fixing function setting section 307.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a motor drive technique for providing an efficient drive waveform to a rotation detection position of a rotor.

  There is a technology for realizing efficient rotational drive by detecting the rotational position of the rotor by the position detection mechanism unit and applying a drive waveform to the motor. In the motor configuration disclosed in Patent Document 1, a magnet is disposed on the rotor (rotor) side and a coil winding is disposed on the stator (stator) side, the low resolution rectangular wave position detection sensor is effective. Generate a sinusoidal drive signal in phase. Further, Patent Document 2 discloses a technique for improving the resolution of rectangular wave change of a position detector. This is a technique for improving the efficiency of rotational driving by compensating the amount of deviation when the relationship between the rotor detection phase and the drive waveform phase deviates from the target phase relationship.

Unexamined-Japanese-Patent No. 2014-45646 JP, 2016-154422, A

  The conventional technique is a technique for performing compensation processing after it is detected that the phase relationship has a difference from the ideal value based on the ideal phase relationship between the rotor rotational phase and the drive waveform phase. Therefore, a delay occurs in the reaction from the detection of the difference to the completion of the compensation process. If the delay time is long, there is a possibility that the potential of the reaction possessed by the mechanism unit can not be fully exhausted at the time of acceleration / deceleration or disturbance.

As a method of improving the accuracy of the position detection mechanism, there is a method of enhancing the resolution of the rectangular wave signal. In this method, position detection can not be performed unless sufficient rectangular signal change detection results can be obtained during high-speed rotation due to the frequency characteristics of the signal. In addition, when the command value of the phase relationship between the rotor rotational phase and the drive waveform phase is changed, the continuity of the drive waveform is lost to form a discontinuous waveform, which may cause vibration or noise of the motor.
An object of the present invention is to enable generation of a drive waveform with a small reaction delay in a motor drive device that generates an efficient drive waveform based on a rotation detection position, and to suppress reverse operation of the motor when vibrating due to disturbance or the like. is there.

  A motor drive device according to an embodiment of the present invention comprises: setting means for setting a rotational direction of a rotor; detection means for detecting a rotational position of the rotor; generation means for generating a drive waveform to a motor; Control means for performing synchronous control to synchronize the phase of the position and the phase of the drive waveform, and the phase between the rotational position and the phase of the drive waveform in a synchronized state, between the rotational position and the drive waveform And phase difference setting means for setting the phase difference. When the direction corresponding to the change of the rotational position detected by the detection means is different from the rotational direction set by the setting means, the control means is reverse to the set rotational direction, which is the opposite direction. Control to suppress the rotation.

  According to the present invention, in a motor drive device that generates an efficient drive waveform based on a rotation detection position, it is possible to generate a drive waveform with a small reaction delay, and to suppress reverse operation of the motor when vibrating due to disturbance or the like. it can.

FIG. 1 is a block diagram illustrating a system overview of an embodiment of the present invention. It is a schematic diagram which shows the position detection structure in the motor of embodiment of this invention. It is a figure explaining the process by a position ENC circuit and a drive waveform generation circuit. It is a figure which shows the relationship between a position detection signal and a detection position count. It is a figure which shows the relationship between the drive waveform of a motor, and phase count. It is a flowchart explaining the process of 1st Embodiment of this invention. It is a flowchart explaining the process following FIG. It is a figure which shows the state which has a stable stop relationship between a rotor magnet phase and a drive waveform phase. It is a figure which shows the state which a normal rotation torque generate | occur | produces to a motor. It is a figure which shows the behavior at the time of acceleration of a motor. It is a figure which shows the rotor magnet phase at the time of electric current phase compensation processing, and a drive waveform phase. It is a figure which shows the behavior at the time of steady speed of a motor, and the deceleration stop. It is a figure which shows the rotor magnet phase and drive waveform phase at the time of generation | occurrence | production of unintended reverse torque. It is a figure explaining the processing for controlling unintended reversal operation. It is a figure which shows the rotor magnet phase and drive waveform phase at the time of generation | occurrence | production of deceleration torque. It is a flowchart explaining the process of 2nd Embodiment of this invention. It is a flowchart explaining the process following FIG. It is a figure explaining processing for controlling unintended reversal operation in a 2nd embodiment. It is a figure explaining the process at the time of the movement of the mechanical member in 2nd Embodiment. It is a figure explaining the process at the time of fixation of the mechanical member in 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The motor drive device of the present embodiment is applicable to various devices such as an imaging device, an optical disk device, a printer, a projector and the like.

First Embodiment
FIG. 1 is a block diagram for explaining an outline of a system according to the present embodiment, and shows an example of the configuration of a motor drive apparatus including an electric circuit for drive. The stepping motor 101 is provided with an ENC (for encoding) magnet 103 on a rotor shaft 102. The ENC magnet 103 is magnetized so that the magnetic field generated on the circumference around the rotation axis generates a sinusoidal magnetic field according to the rotational position. The stepping motor 101 also includes a reset mechanism 121. The reset mechanism 121 is configured to output a signal that changes at one specific position according to the rotation of the rotor shaft 102. This signal is a signal for providing a reference of the absolute position related to the rotational position of the motor. Specifically, as the reset mechanism 121, the rotor shaft 102 is a screw shaft, and a slit is formed in a moving body that translates according to the rotation of the screw shaft. When the slit shields the photo interrupter, its output signal changes.

  The Hall element package 104 is a magnetic detection unit of the ENC magnet 103, and includes a plurality of Hall elements. For example, the Hall elements 105 and 106 detect the change of the magnetic field due to the rotation of the ENC magnet 103 at each position, and output a detection signal to the amplifier 107. A specific example will be described with reference to FIG.

  FIG. 2A is a perspective view showing an example of the appearance of the stepping motor 101. FIG. A short cylindrical ENC magnet 103 is installed on the rotor shaft 102 of the stepping motor 101. The Hall element package 104 is disposed at a position where the magnetic field generated by the ENC magnet 103 can be detected. The wiring member 201 is drawn out from the stepping motor 101, and the wiring member 201 is connected to a motor driver 113 described later.

  FIG. 2B is a schematic view showing the positional relationship between the ENC magnet 103 and the Hall elements 105 and 106. As shown in FIG. The ENC magnet 103 is a magnet with five poles (10 poles), and an area of 36 degrees is magnetized. When viewed from the center position of the ENC magnet 103, the Hall elements 105 and 106 are disposed equidistant from the center position. The arrangement is such that the angles of the Hall elements 105 and 106 with respect to the central position, that is, the physical angle (physical angle) formed by the two Hall elements with respect to the central position is 18 degrees. The signal phase detected by the two Hall elements has a phase difference of 90 degrees.

  The amplifier 107 in FIG. 1 amplifies weak signals input from the Hall elements 105 and 106 and outputs the amplified signals to the AD conversion circuit 108 in the subsequent stage. The AD conversion circuit 108 converts the analog voltage signal input from the amplifier 107 into a digital value and digitizes it, and outputs the conversion result to the position ENC circuit 109 as a digital numerical signal.

  The position ENC circuit 109 encodes the signal input from the AD conversion circuit 108. The position ENC circuit 109 includes a processing unit that performs offset adjustment and gain adjustment of the two input signals. The position ENC circuit 109 calculates the TAN value (tangent value) from the two signals after adjustment and then performs ArcTAN operation (inverse tangent operation) to generate rotation angle information. By integrating this rotational angle information, rotational position information is generated. The generated rotational position information is sent to the drive waveform generation circuit 110.

  The drive waveform generation circuit 110 generates a drive waveform for the motor. The drive waveform generation circuit 110 switches between OPEN drive and CLOSE drive. The OPEN drive is a drive that outputs sine wave signals having different driving phases at a preset frequency. The CLOSE drive is a drive that outputs a drive waveform interlocked with the position ENC circuit 109. Switching between OPEN drive and CLOSE drive is performed in accordance with a command from the CPU (central processing unit) 111.

  The CPU 111 instructs the drive waveform generation circuit 110 to switch between OPEN drive and CLOSE drive, and sets the frequency and amplitude gain value of the output sine wave signal at OPEN drive. The CPU 111 also performs initialization setting of the position count value and the like for the position ENC circuit 109. The processing by the position ENC circuit 109 and the drive waveform generation circuit 110 will be described later with reference to FIGS. 3 to 5.

  A PWM (pulse width modulation) generator 112 outputs a PWM signal to the motor driver 113 in accordance with the PWM command value output from the drive waveform generation circuit 110. The PWM signal will be described later with reference to FIG.

  The motor driver 113 performs amplification according to the PWM signal output from the PWM generator 112, and applies a voltage to the A-phase coil 114 and the B-phase coil 115 of the stepping motor 101. The signal applied to the motor is a high frequency voltage signal corresponding to the PWM signal, but the current value signal generated in the coil is the same as when an LPF (low pass filter) is applied by the L (inductance) component of the coil. From this, it is assumed that the coil is effectively the same as when a sinusoidal signal voltage described in FIG. 5 is applied.

  Each of the stator A + 116 and the stator A-117 functions to concentrate and release the magnetic field generated at both ends of the A phase coil. The stator B + 118 and the stator B-119 function to concentrate and release the magnetic field generated at both ends of the B phase coil. The arrangement of the stators A + and A-, the stators B + and B-, and the rotor magnets will be specifically described with reference to FIG.

  In FIG. 2C, the stator A + 116, the stator A-117, the stator B + 118, and the stator B-119 are arranged such that their physical angles are in a positional relationship of 18 degrees. The rotation direction of the rotor magnet 120 is a CW direction or a CCW direction. In this example, a total of five stator groups are arranged. The rotor magnet 120 is located at the center of the stator group, and has five N poles and five S poles, each having a total of 10 poles. The rotor magnet 120 rotates 72 degrees in physical angle each time one sine wave of the drive waveform is output.

  Next, processing of the position ENC circuit 109 and the drive waveform generation circuit 110 will be described in detail. FIG. 3A is a block diagram showing the process of the position ENC circuit 109 and the drive waveform generation circuit 110 in detail. The Apos generation unit 301 and the Bpos generation unit 302 correspond to the position ENC circuit 109. The drive waveform phase determination unit 303 to the rotation direction fixing function setting unit 307 correspond to the drive waveform generation circuit 110.

  The output signal of the Hall element 105 in FIG. 1 is described as a detection signal 1, and the output signal of the Hall element 106 is described as a detection signal 2. The detection signals 1 and 2 are input to the AD conversion circuit 108 via the amplifier 107, and the signal subjected to AD conversion is acquired by the Apos generation unit 301. The Apos generation unit 301 calculates a rotational position using ArcTan (an arctangent) operation. As preprocessing, offset adjustment and gain adjustment of the two input signals are performed. That is, adjustment is made to make the offsets and gains of the two signals identical. This adjustment is performed by detecting the peak value and the bottom value of the two signals by rotating the motor by OPEN drive, and using the detection results. After adjustment, a tangent value is calculated from two sine wave signals having a phase difference of 90 degrees, and rotation angle information (denoted as Apos) is generated by performing an arctangent operation. It is possible to generate rotational position information by calculating a value obtained by integrating the value of the rotational angle. The relationship between the detection signals 1 and 2 and the rotational position information will be described with reference to the example of FIG.

  FIGS. 4A and 4B illustrate signals after adjusting the detected rotational position signals. The signal shown in FIG. 4A is a sine wave signal, and the signal shown in FIG. 4B is a cosine wave signal. FIG. 4C shows the change of the count value of the detection position. The horizontal axis represents the amount of rotation of the rotor. In this embodiment, when signals of two Hall elements are output for one wavelength of a sine wave, position detection can be performed with position resolution for 1024 counts. The count value of the detection position is stored in the storage area of the Apos generation unit 301 of FIG.

  FIG. 3B shows Apos, and the horizontal axis of the graph represents the amount of rotation of the rotor. The value of Apos is a count value proportional to the amount of rotation of the rotor. After the Apos generation unit 301, the Bpos generation unit 302 takes over the processing.

  The Bpos generation unit 302 generates information (referred to as Bpos) having an arbitrary offset value for Apos. The CPU 111 can rewrite Bpos to any value at any timing, and records the value rewritten at the timing and the difference between Bpos and Apos as an offset value. FIG. 3C shows Bpos. The horizontal axis represents the amount of rotation of the rotor. The Bpos generation unit 302 generates a Bpos value to which the recorded offset value is always added with respect to the Apos value shown in FIG. 3 (B). The Bpos value is a sawtooth signal value that changes periodically with respect to the amount of rotation between zero and an upper limit value.

  The information of Bpos generated by the Bpos generation unit 302 is input to the drive waveform phase determination unit 303. The drive waveform phase determination unit 303 finally determines phase count information of the drive waveform to be applied to the A phase coil 114 and the B phase coil 115. The drive waveform phase determination unit 303 outputs a PWM value corresponding to the phase count to the PWM generator 112 of FIG. The drive waveform phase determination unit 303 can switch between OPEN drive that outputs phase count information and position-linked drive that outputs phase count information based on the Bpos value according to an instruction from the OPEN drive count unit 304. The OPEN drive and the position interlocked drive can be switched by the CPU 111 performing setting on the drive waveform phase determination unit 303.

When performing OPEN drive, the CPU 111 instructs the OPEN drive count unit 304 to the frequency of the drive waveform, and sets the amplitude gain of the drive waveform in the drive waveform phase determination unit 303. Thereby, the drive waveform phase determination unit 303 outputs a drive waveform having a desired frequency and a desired amplitude. On the other hand, in the case of position-linked drive, the drive waveform phase determination unit 303 calculates a value obtained by adding a predetermined offset value to the lower 10 bits of Bpos. The predetermined offset values are as follows.
The first offset value (STC_OFS value) set by the CPU 111 through the steady-state phase difference setting unit 305
Second offset value (PHS_OFS value) set by the CPU 111 through the driving phase difference setting unit 306.

  The values to which these offsets are added are calculated, and the count value of the drive waveform phase is obtained. The output value of the phase corresponding to the count value is selected as the output value of the drive waveform. This relationship is shown by the graphs of FIGS. 3 (D) and 3 (E). FIG. 3D shows the relationship between the lower 10 bit value of Bpos and the amount of rotation. FIG. 3E shows the drive waveform after the offset is applied. The horizontal axis represents the amount of rotation of the rotor. Both STC_OFS and PHS_OFS are added to Bpos to give an offset value. As will be described later, the STC_OFS plays a role in managing the detection position count of the rotor and the stable position of the drive waveform count. PHS_OFS is assigned a role of managing phase difference for torque generation.

  The rotation direction fixing function setting unit (hereinafter simply referred to as the fixing function setting unit) 307 performs an unintended reverse driving when an overload or the like is applied during CLOSE driving in which the drive waveform generation circuit 110 and the position ENC circuit 109 are interlocked. Work to prevent The detailed operation will be described later.

  Drive waveform generation circuit 110 determines the phase of the drive waveform by drive waveform phase determination unit 303 to fixed function setting unit 307 in FIG. 3A, and outputs a PWM command value corresponding to the drive waveform to PWM generator 112. . The PWM generator 112 outputs a PWM signal to the motor driver 113 according to the PWM command value output from the drive waveform generation circuit 110. The relationship between the sine wave position count value and the output PWM value (Duty% value) will be described with reference to FIG. In both FIGS. 5A and 5B, the horizontal axis represents a table number, and the resolution is 1024 as in the case of the output value shown in FIG. The vertical axis represents the duty% value of the PWM signal.

  In FIG. 5A, the horizontal axis is plus counted and the B-phase drive voltage waveform leads by 90 degrees with respect to the A-phase drive voltage waveform. This shows the case where the motor rotates in the CW direction. Conversely, in FIG. 5B, the horizontal axis is counted minus, and the A-phase drive voltage waveform leads by 90 degrees with respect to the B-phase drive voltage waveform. This shows the case where the motor rotates in the CCW direction. The duty% value on the vertical axis increases or decreases in accordance with the gain setting value by the CPU 111. In this embodiment, it is assumed that an appropriate gain value is set so as not to disturb the rotational movement of the motor.

  6 and 7 are flowcharts showing the flow of processing in the present embodiment. The CPU 111 performs the following control according to a predetermined program. When the drive sequence starts, the process proceeds to the process of S601.

  At S601 in FIG. 6, the CPU 111 executes setting processing for turning off position interlocking drive. That is, the setting is such that OPEN drive works. At S602, the CPU 111 determines the detection state of the reset signal output from the reset mechanism 121. The reset signal is a binary signal that changes to High or Low when the detected member passes a predetermined position, as the detected member attached to the screw mechanism of the rotor shaft 102 moves. When the motor drive device applies a B-phase leading drive waveform to the stepping motor 101 to perform CW rotation, the side on which the detected member advances is the side that outputs the High level as the reset signal. When the motor drive device applies a drive waveform of A-phase lead to the stepping motor 101 to perform CCW rotation, the side on which the detected member advances is the side that outputs Low level as the reset signal. In order to detect the position where the reset signal changes and determine the absolute position, the determination process of S602 is performed.

  If the reset signal is low at S602, the process proceeds to S603, and if the reset signal is high at S602, the process proceeds to S604. In step S603, the CPU 111 instructs the OPEN drive count unit 304 (FIG. 3) to generate a drive wave having a B-phase leading waveform, and performs control to rotate the motor. In step S604, the CPU 111 instructs the OPEN drive count unit 304 to generate a drive wave having an A-phase leading waveform, and performs control to rotate the motor. After the process of S603 or S604, the process proceeds to the process of S605.

  In step S605, the CPU 111 determines whether the state of the reset signal has changed. The CPU 111 monitors the reset signal, and if a change occurs in the reset signal, the process proceeds to step S606. If there is no change in the reset signal, the monitoring is continued and the determination process of step S605 is repeated. In S606, the CPU 111 outputs a command to stop the progression of the drive waveform to the OPEN drive count unit 304. The stop position at this time is the reference position of the position count. In the next S607, a Bpos value for performing final position management of the detected position is initialized, and a process of writing zero in Bpos is performed.

  In the subsequent S608, processing is performed to write, as STC_OFS, a value obtained by subtracting the lower 10 bits of Bpos from the phase count value of the drive waveform held in the drive waveform phase determination unit 303 in the stopped state of the rotor. The value of STC_OFS is a value for preventing the output phase of the drive waveform from being shifted at the moment when the position interlocked drive is turned on. At the time of S608, as a result of the OPEN drive waveform, the rotor magnet 120 is stably stopped while outputting a certain drive waveform phase. The drive waveform phase after position interlock drive is set to ON is generated based on the lower 10 bits of Bpos. Immediately after the position-linked drive is set to ON, the value of STC_OFS is added to the lower 10 bits of Bpos. Since the value after the addition is output as the phase count value of the drive waveform, it is ensured that the phase count value of the drive waveform does not change before and after the position interlock drive is on and off. Next, the process proceeds to the process of S609.

  In step S609, the CPU 111 turns on the rotation direction fixing function through the fixing function setting unit 307, and sets the rotation direction to the CW direction, that is, the positive direction in the position detection count direction. In step S610, the CPU 111 sets the position interlocking drive to on. At this time, it is assumed that offset PHS_OFS is set to zero. As described above, the output phase of the drive waveform does not change immediately after the on setting of position-linked drive.

  In S611, a rotational torque generation operation using a position interlocking function is performed. Specifically, 256 which is a value corresponding to 90 degrees in the drive waveform phase is set to PHS_OFS. The phenomenon which generate | occur | produces in a motor at this time is later mentioned using FIGS. 8-10.

  In S612, the CPU 111 determines whether or not the detected position of the rotor is equal to or greater than a preset first position (denoted as X1). When the detected position is X1 or more, the process proceeds to S613, and when the detected position is less than X1, the determination process of S612 is repeated. In step S613, the CPU 111 sets a value 512 obtained by further adding 256 to the value 256 in step S611 with respect to PHS_OFS. Next, proceeding to S614 in FIG. 7, the CPU 111 determines whether or not the detected position of the rotor is greater than or equal to a preset second position (denoted as X2). The size of X2 is assumed to be larger than the size of X1. If the detected position is X2 or more, the process proceeds to S615, and if the detected position is less than X2, the determination process of S614 is repeated. In S615, the CPU 111 sets a value 640 obtained by further adding 128 to the value 512 in S613 with respect to PHS_OFS. These processes are performed for phase compensation of the motor current. Details of the process will be described later with reference to FIGS. 10 and 11.

  In the subsequent S616, the CPU 111 performs a process of determining the deceleration start position of the motor. If it is determined that the detected position of the rotor is equal to or greater than the deceleration start position, the process proceeds to the process of S617. If it is determined that the detected position of the rotor is less than the deceleration start position, the determination process of S616 is repeated. With regard to the deceleration start position, the drive characteristics of the motor and the mechanism are checked in advance, and a sufficient amount of rotation is required to obtain a sufficient deceleration effect when the desired deceleration torque is applied. The position of is assumed to be set. In the following S617, the CPU 111 sets -256 as the value of PHS_OFS so that the rotational torque in the CCW direction, that is, the deceleration torque serving as the brake in CW rotation, is applied to the motor.

  In step S618, the CPU 111 determines whether the detected position of the rotor is equal to or greater than the deceleration end position. If the detected position of the rotor is equal to or greater than the deceleration end position, the process proceeds to S619, and if the detected position of the rotor is less than the deceleration end position, the determination process of S618 is repeated. Regarding the deceleration end position, the drive characteristics of the motor and the mechanism are checked in advance, and sufficient deceleration is possible, and after reaching the end of the deceleration, the target reaching position can be reached by inertia. The position shall be set.

  In step S619, the CPU 111 sets zero as the value of PHS_OFS. That is, the phase relationship between the detected position and the drive waveform shifts from the phase relationship in which the brake torque is applied to the phase relationship in which the rotation torque is not generated. In the following S620, the CPU 111 determines whether or not the detected position of the rotor is equal to or greater than a preset target stop position (referred to as TP). If the detected position of the rotor is equal to or greater than the target stop position TP, the process proceeds to step S621. If the detected position of the rotor is less than the target stop position TP, the determination process of step S620 is repeated. In step S621, the CPU 111 turns off position interlocking drive and fixes the phase of the drive waveform. This causes the motor to stop rotating. This completes the series of drive sequences.

  When the rotation detection position of the rotor does not change as desired for a predetermined time or when the reverse movement amount becomes larger than a predetermined amount, the CPU 111 executes notification processing indicating that the driving state of the motor is not normal. The reverse movement amount corresponds to the difference between the rotational position held while the motor is driven and the rotational position detected by the position detection unit, and is a difference in the reverse direction. In such a case, the CPU 111 performs control to temporarily stop the drive sequence of the motor and shift to a safe restart sequence.

  The process of S611 in FIG. 6 will be specifically described with reference to FIGS. 8 to 10. FIG. 8A is a schematic view of the arrangement of the stator group shown in FIG. 2C in which the stators are arranged in a horizontal row. FIG. 8B is a view schematically showing what voltage is applied to the stator group in the circumferential direction of the motor. FIG. 8C is a diagram showing the strength of the magnetic field corresponding to the circumferential position generated by the stator group by the voltage application. FIG. 8 (D) is a diagram showing the magnetization phase of the rotor magnet 120 shown in FIG. 2 (C). In FIG. 8 (B) to (D), the horizontal axis represents the position. FIG. 8 shows the state of S611 in FIG. 6, and the relationship between the NS magnetic pole phase of the magnetic field generated by the stator group and the NS magnetic pole phase of the rotor magnet 120 is a relationship in which the rotor is stably stopped. .

  FIG. 9 is an explanatory view showing a state after PHS_OFS is set to 256 in S611 of FIG. FIGS. 9A to 9D correspond to FIGS. 8A to 8D, respectively. In the state shown in FIG. 9, the magnetic field generated by the stator group is at a position advanced by 90 degrees as compared with the state shown in FIG. In this case, the relationships shown in FIGS. 8C and 8D change to the relationships shown in FIGS. 9C and 9D. As a result, as shown in FIG. 9D, an attractive force is drawn to the right of the rotor magnet 120, that is, a rotational torque (forward torque) in the CW direction.

  FIG. 10 is a graph for explaining the behavior of the motor. FIG. 10A shows a time change of Bpos, the horizontal axis is a time axis, and the vertical axis represents the position of the rotor. X1 and X2 represent predetermined positions described in S612 of FIG. 6 and S614 of FIG. FIG. 10 (B) shows the time change of the lower 10 bit value of Bpos. FIG. 10C shows the time change of the drive waveform phase count value. Time t1 indicates timing when 256 is set as the value of PHS_OFS in S611 of FIG. Time t2 shows the execution timing of S613 of FIG. 6, and time t3 shows the execution timing of S615 of FIG. 10D and 10E respectively show the temporal change of the drive waveform magnetic field generated in the stator A + 116 and the temporal change of the drive waveform magnetic field generated in the stator B + 118 based on the drive waveform phase count value. .

  When PHS_OFS is set to 256 at time t1 in FIG. 10, the difference between the lower 10 bits of Bpos shown in FIG. 10B and the drive waveform phase count value shown in FIG. 10C. 256 occur. As a result, the phase of the drive waveform leads by 90 degrees from the rotational phase of the rotor, and a torque in the CW rotational direction is generated. As the motor rotates, Bpos corresponding to the detected position advances, and thereby the phase count value of the drive waveform also advances. By this loop processing, the phase difference between the two waveforms shown in FIGS. 9B and 9C is always maintained, and the rotational torque continues to be applied. As a result, as shown in FIG. 10A, the motor is accelerated and the rotational speed of the motor is increased.

  At times t2 and t3 in FIG. 10, the phase difference between the lower 10-bit value of Bpos shown in FIG. 10B and the drive waveform phase count value shown in FIG. 10C are 512 and 640, respectively. I understand. In FIG. 10A, the first position X1 corresponding to time t2 represents the position at 2048, and the second position X2 corresponding to time t3 represents the position at 3072. The reason why the phase difference is changed stepwise in this way is to cope with the delay of the current phase with respect to the phase of the applied voltage application waveform according to the amount of rotation of the motor. During extremely low speed rotation, there is almost no phase difference between the applied voltage waveform and the current waveform of the motor coil. However, as the amount of rotation increases, the current waveform is delayed with respect to the applied voltage waveform due to the influence of the current delay component of the coil and the back electromotive force due to the motor structure. The effect is greater at higher speeds. Therefore, the delay of the current waveform with respect to the applied voltage waveform can be suppressed by executing the processing of S613 of FIG. 6 and S615 of FIG.

  FIG. 11 is a view for explaining the relationship between the applied voltage waveform and the generated magnetic force in the state of transitioning to the steady state after execution of S <b> 615 in FIG. 6. FIGS. 11A to 11D correspond to FIGS. 8A to 8D and 9A to 9D, respectively.

  11 and 8 show that the phase of the applied voltage leads 225 degrees from the state where the magnetic field and the rotor magnet are in balance. 225 degrees is a phase difference corresponding to the setting value 640 (FIG. 6: S615) of PHS_OFS. At this time, since the motor is rotating at a high speed, the current is significantly delayed with respect to the voltage due to the current delay of the coil and the back electromotive force of the motor. In FIG. 11, this delay amount is 135 degrees. Since the current flowing in the coil and the generated magnetic field are in a proportional relationship, the phases of the coil current and the generated magnetic field coincide. Therefore, the phase of the generated magnetic field shown in FIG. 11C lags behind the voltage phase by 135 degrees. However, in comparison with the stable stop phase shown in FIG. 8, the phase advances by 90 degrees with respect to the phase of the rotor magnet, resulting in the same attraction relationship as the magnetic field shown in FIG. From the phase relationship of stable stop, the torque efficiency is the highest in the phase relationship in which the magnetic field applied for rotation is advanced by 90 degrees. In the present embodiment, it is assumed that the characteristics of the motor are measured in advance, and the phase of the applied voltage when the maximum speed is obtained is specified as the phase advancing state of 225 degrees. As described with reference to FIGS. 6 and 7 in the processes of S611 to S615, a process of gradually raising the phase difference PHS_OFS is executed. This is because at the time of low speed rotation, the effect of the current delay is small, and therefore, if a large phase difference is added from the beginning, rotation acceleration can not be performed with efficient torque. The values of X1 and X2, which are the first and second positions corresponding to the switching point of the phase difference, are set in advance based on the measurement results by measuring the acceleration characteristic and the current delay characteristic of the motor in advance. The above phenomenon is remarkable in the motor having a large back electromotive force action and a large delay component of the coil, and in this embodiment, such a motor is assumed.

  Next, the behavior of the motor after acceleration will be described with reference to FIG. FIG. 12 shows a state in which the motor moves to a constant speed state at a constant speed after acceleration, further decelerates and runs idle, and stops at the target stop position TP. FIG. 12A shows the time change of Bpos, the horizontal axis is a time axis, and the vertical axis represents a position. FIG. 12 (B) shows the time change of the rotational speed of the motor, the horizontal axis is a time axis, and the vertical axis shows the rotational speed. Further, FIG. 12C shows a temporal change of the lower 10 bits of Bpos. FIG. 12 (D) shows the time change of the drive waveform phase count value. The drive waveform phase count value corresponds to a value obtained by adding the command phase difference to the value shown in FIG. 12C and normalized to a value of 0 to 1023. 12 (E) and 12 (F) respectively show the temporal change of the drive waveform magnetic field generated in the stator A + 116 and the temporal change of the drive waveform magnetic field generated in the stator B + 118 based on the drive waveform phase count value. In FIG. 12, the motor is in the constant speed state in the period from time t4 to time t5, and the motor is in the decelerating state in the period from time t5 to time t6. The motor is idle during the period from time t6 to time t7.

  The motor rotates in the forward rotation direction from S615 to S616 in FIG. 7, and time t4 shown in FIG. 12 indicates the timing at which the velocity becomes constant after the final phase difference command value is determined. Time t5 indicates the timing at which the process of S617 in FIG. 7 is performed. The reverse operation which may occur when the motor is rapidly decelerated due to a disturbance such as an external force in a period (t4 to t5) in which the value of PHS_OFS becomes 640 will be described below using FIGS. 12 and 13.

  During the period (t4 to t5) of the constant speed state shown in FIG. 12, it is assumed that rapid deceleration occurs due to external force, and the current delay action becomes so small as to be negligible. FIG. 13 is a diagram showing that reverse torque is generated in the rotor. The relationship between the applied voltage waveform, the generated magnetic field, and the rotor magnet phase shown in FIGS. 11 (A) through 11 (D) is the relationship shown in FIGS. 13 (A) through 13 (D). In this case, the rotation of the motor is rapidly decelerating, and the current delay of the coil and the current delay due to the back electromotive force become very small. That is, the phase delay set to 135 degrees in FIG. 11 represents a case where these actions are so small that they can be ignored in FIG. The phase of the applied voltage shown in FIG. 13 (B) leads 225 degrees as in FIG. 9 with respect to the magnetization phase of the rotor shown in FIG. 13 (D). However, since the current delay is so small that it can be ignored, the phase of the generated magnetic field shown in FIG. 13 (C) becomes the same as the phase of the applied voltage shown in FIG. 13 (B). The rotor magnet of FIG. 13 (D) receives reverse torque reverse to the intended rotation direction. If this state is maintained for a predetermined time or more, it is feared that the vehicle will run away in the reverse rotation direction. Then, the solution method of this subject is demonstrated in detail with reference to FIG.

  As described in S609 of FIG. 6, when the setting of the rotation direction fixing function is on and the setting of the rotation direction is performed by the fixed function setting unit 307, the process illustrated in FIG. 14 is executed. This process is performed at the time of synchronous control of the detection position and the output drive waveform phase shown in FIGS. 10 (B) and (C) and FIGS. 12 (C) and 12 (D). FIG. 14 shows the time change of the drive waveform phase 1301 and the time change of the lower 10 bits 1302 of the detection position, and shows that both are synchronized while maintaining the phase difference of the phase difference 1303. The horizontal axis is a time axis, and indicates time m1 to m11. The detection position is determined every predetermined AD conversion cycle, and the value obtained by adding the phase difference to the lower 10 bits of the detection position is output as the phase value of the drive waveform. Each time interval from time m1 to m11 corresponds to an AD conversion cycle. The phase difference 1303 is set to a value 640, for example, during the period from time t4 to t5 in FIG.

  A change between the detection position at time m4 and the detection position at time m5 is indicated by a range 1304. This is an example in which the count value of the detection position changes in the negative direction due to the influence of a disturbance or the like. In the present embodiment, the fixed function setting unit 307 sets the CW direction, that is, the positive direction as the position count value (FIG. 6: S609). In this case, at the time of position detection at time m5, the maximum value in the positive direction detected up to this time is adopted as the detection position. That is, the value detected at time m4 is used. Therefore, as shown by the drive waveform phase 1305, the drive waveform phase output at time m5 is a value obtained by adding the phase difference 1303 to the phase corresponding to the detection position at time m4. As a result, since the drive waveform phase does not change in the negative direction, reverse rotation is suppressed. The fixed function setting unit 307 functions to maintain the torque by the drive waveform at the torque in the set rotational direction.

  Similarly, a change in each detection position at time m7, m8 and m9 is indicated by a range 1306. Due to the influence of disturbance or the like, the count value of the detected position continuously changes in the negative direction. Since the positive direction of the count value of the position is set by the fixed function setting unit 307, the maximum value in the positive direction detected so far is adopted at the time of position detection at times m8 and m9. That is, the value detected at time m7 is used. Therefore, as indicated by the drive waveform phase 1307, the drive waveform phases output at time m8 and m9 are values obtained by adding the phase difference 1303 to the phase corresponding to the detection position at time m7. As a result, since the drive waveform phase does not change in the negative direction, reverse rotation is suppressed. As described above, it is determined whether or not the rotation direction set in the cycle of position detection matches the actual rotation direction by taking the difference in position for each timing of position detection, and in the case where they do not coincide. Control to suppress reverse rotation can be performed.

  If it is determined at S616 in FIG. 7 that the detected position is at least the deceleration start position, the process proceeds to S617 (time t5 in FIG. 12), and deceleration control is performed. FIG. 15 is a diagram for explaining the state at S617. FIGS. 15A to 15D correspond to FIGS. 8A to 8D, however, the magnetic field generated by the stator group is delayed by 90 degrees as compared with the state shown in FIG. . Therefore, in the rotor magnet 120 shown in FIG. 15D, an attractive force that is pulled to the left, that is, a rotational torque (deceleration torque) in the CCW direction is generated. Since this torque acts as a brake torque with respect to the rotational torque in the CW direction at the stage of S617 of FIG. 7, the motor deceleration operation is performed quickly using this.

  Thereafter, at time t6 in FIG. 12, as shown in S619 in FIG. 7, zero is set as the value of PHS_OFS, and a transition to an idle period is made. At time t7 in FIG. 12, as shown in S621 in FIG. 7, the interlocking function is set to be off. The position of the motor reaches the target stop position TP, and the motor stops its rotation.

  In the present embodiment, it is possible to generate an efficient drive waveform for the motor based on the detected rotational position while suppressing the continuity of the drive waveform from being lost and becoming a discontinuous waveform. At that time, the reaction delay can be reduced. In addition, it is possible to prevent an unintended reverse operation caused by a sudden deceleration due to a sudden excessive load, a disturbance, or the like while performing efficient control for compensating the current delay.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the first embodiment, the case where the rotation direction in position interlocking drive is one direction has been described. In the present embodiment, the case of performing rotational operation in the direction opposite to the current time in position interlocking drive will be described. In this case, it is possible to prevent an unintended reverse operation caused by a sudden overload or disturbance while preventing the continuity of the drive waveform from being lost and becoming a discontinuous waveform.

  The process in the present embodiment will be described with reference to the flowcharts shown in FIGS. The CPU 111 performs the following control according to a predetermined program. When the drive sequence starts, the process proceeds to the process of S601. The description of the processing of S601 to S613 in FIG. 6 is omitted. The processes in S614 to S621 in FIG. 16 are the same as those in FIG. In this embodiment, the process of S1601 is added after S615 in FIG. 16, and the process of S1616 is performed instead of S617 between S616 and S618.

  At S1601, the CPU 111 performs processing to determine whether or not to perform the motor reversing operation. For example, when the command is changed by the operation member or the like in the rotation direction opposite to the current rotation direction, the CPU 111 performs the determination processing based on the signal change of the operation member. If it is determined that the process of the reversing operation is to be performed, the process proceeds to the process of S1602. If it is determined that the process of the reversing operation is not performed, the process proceeds to step S616.

  In S1602, the CPU 111 sets the rotation direction fixing function to OFF via the fixing function setting unit 307. Thereafter, the CPU 111 sets the reverse rotation correction function to ON in S1603. The reverse rotation correction function is a function realized by the drive waveform generation circuit 110, and unintended drive when excessive load or the like is applied at the time of position interlock drive where the drive waveform generation circuit 110 and the position ENC circuit 109 interlock. Work to prevent. In the reverse rotation correction function, a difference calculation process is performed to acquire the difference amount of the rotation detection position for each predetermined period, and a process of determining whether the difference amount exceeds the threshold value is performed. The predetermined period is a period corresponding to the AD conversion cycle, that is, the update timing of the rotation detection position. Details of the reverse rotation correction function will be described later with reference to FIGS. 18 to 20.

  After S1603, the CPU 111 calculates a threshold (denoted as A) of the reverse rotation correction function in S1604. In the present embodiment, a process of setting the difference amount of the rotation detection position for each AD conversion cycle immediately before the reverse rotation correction function is set to ON as the threshold A is performed. However, for the threshold A, for example, an average value of the difference amount of the rotation detection position for each AD conversion cycle in a state where the reverse rotation correction function is set to OFF may be used as the threshold A. Alternatively, the threshold A determined from the difference amount of the rotation detection position for each AD conversion cycle according to the speed before the reversing operation may be stored in the memory by examining the drive characteristics of the motor and the mechanism in advance. . Also, the threshold A need not be a fixed value. For example, the drive characteristics of the motor and the mechanical unit may be checked in advance, and the threshold value A may be set as a variable value that changes every predetermined time.

  In S1605, a rotational torque generation operation using a position interlocking function is performed. Specifically, PHS_OFS is set to -256 which is a value corresponding to -90 degrees in the drive waveform phase. A rotational torque in the CCW direction, that is, a deceleration torque serving as a brake during CW rotation, is applied to the motor. Thereafter, the process proceeds to S1606 in FIG.

  In S1606, the CPU 111 determines whether a predetermined time until the reverse operation process is completed has elapsed. For the time until the reversal operation processing is completed, the drive characteristics of the motor and mechanism are checked in advance, and the data of the time taken to complete the reversal according to the speed before the reversal operation is held in the memory I assume. If it is determined that the time set in advance has elapsed, the process advances to step S1607, and if it is determined that the time has not elapsed, the process advances to step S1611.

  In S1611, the CPU 111 determines whether the difference amount (magnitude of the difference) of the rotation detection position for each AD conversion cycle obtained by the difference calculation processing is outside a predetermined range, for example, a threshold value or more (A or more). Do. If it is determined that the difference amount of the rotation detection position for each AD conversion cycle is within the predetermined range, that is, less than the threshold (less than A), the process proceeds to S1606 and the determination process is repeated. On the other hand, when it is determined that the difference amount of the rotation detection position for each AD conversion cycle is equal to or more than the threshold (A or more), the process proceeds to S1612.

  In S1612, the CPU 111 determines whether or not the amount of difference in rotation detection position for each AD conversion cycle is equal to or greater than a predetermined value (denoted as B). The predetermined value B is a threshold for determination which is set in advance as an impossible value as the difference amount of the rotation detection position for each AD conversion cycle. For example, the predetermined value B is set as a limit value larger than the amount of change of the rotational position when the motor operates at the maximum speed. It is assumed that the relationship of “threshold A <predetermined value B” is always established. If it is determined in S1612 that the difference between the rotation detection positions for each AD conversion cycle is equal to or greater than the predetermined value B, the process advances to S1613. When it is determined that the difference between the rotation detection positions for each AD conversion cycle is smaller than the predetermined value B, that is, the difference between the rotation detection positions for each AD conversion cycle is equal to or greater than the threshold (A or more) and limited If the value is smaller than the predetermined value B, the process advances to step S1614.

  At S1613, the CPU 111 executes an emergency stop process. For example, when the mechanical member connected to the motor is forcibly moved from the outside, the CPU 111 executes notification processing indicating that the driving state of the motor is not normal. In this case, the CPU 111 temporarily stops the drive sequence of the motor, performs control to shift to a safe restart sequence, and ends the drive sequence. This process will be described later with reference to FIG.

  At S1614, the CPU 111 performs adjustment processing regarding torque generation in the CCW direction. In that case, a value corresponding to -90 degrees in the drive waveform phase is not given to the rotation detection position, but a value obtained by adding the threshold A to the value of the previous rotation detection position (previous value) A process of setting a value corresponding to -90 degrees in the drive waveform phase is performed. This process will be described later with reference to FIG. After the process of S1614, the process returns to S1606 and the determination process is repeated. The threshold A in the present embodiment is set by the difference amount of the rotation detection position for each AD conversion cycle immediately before the reverse rotation correction function is set to ON. A phase of a drive waveform obtained by adding a value corresponding to a predetermined phase difference to a value obtained by adding a predetermined value (for example, threshold A) corresponding to the difference amount when the rotation detection position is less than the threshold to the previous value The drive control of the motor is performed in accordance with.

  When the process proceeds from step S1606 to step S1607, in step S1607, the CPU 111 determines whether the difference amount of the rotation detection position for each AD conversion cycle obtained by the difference calculation process is outside a predetermined range, for example, a threshold or more (A or more). Do. If it is determined that the difference between the rotation detection positions for each AD conversion cycle is equal to or greater than the threshold, the process advances to step S1608. If it is determined that the difference between the rotation detection positions for each AD conversion cycle is within a predetermined range, that is, less than the threshold (less than A), the process advances to step S1610. The determination process using the threshold A is an example, and the present invention is not limited to this. For example, it is possible to arbitrarily set the threshold with a value smaller than A, and the determination condition may be that the difference amount continuously exceeds the threshold A for a predetermined number of times or more.

  At S1610, the CPU 111 executes an emergency stop process. For example, when the motor is out of step or the mechanical member is forcibly fixed from the outside, the CPU 111 executes notification processing indicating that the drive state of the motor is not normal. In this case, the CPU 111 temporarily stops the drive sequence of the motor, performs control to shift to a safe restart sequence, and ends the drive sequence. This process will be described later with reference to FIG.

  In step S1608, the CPU 111 determines that the reverse operation has been completed normally, and sets the reverse rotation correction function to off. In the next S1609, the CPU 111 turns on the rotation direction fixing function through the fixed function setting unit 307, and sets the rotation direction in the CCW direction, that is, in the minus direction in the position detection count direction. Thereafter, the process proceeds to S1601 in FIG.

  In FIG. 16, the process of S1616 is performed after S616. That is, if it is determined at S616 that the detected position of the rotor is equal to or greater than the deceleration start position, the process proceeds to S1616. The CPU 111 sets +256 as the value of PHS_OFS so that a rotational torque in the CW direction, that is, a deceleration torque serving as a brake during CCW rotation, is applied to the motor. After that, it advances to S618.

  In the example of FIG. 16 and FIG. 17, the stop processing is performed after the reverse operation and the sequence of ending the series of processing has been described. The present invention is not limited to this, and for example, it is possible to perform the stop process after repeating the reverse operation in the same manner.

  Next, the reverse rotation correction function described in S1603 of FIG. 16 will be described in detail with reference to FIG. FIG. 18A is a diagram showing a time change of the drive waveform phase 1731 and a time change of the detection position 1732 when the reverse rotation correction function is not used. FIG. 18B is a diagram showing a temporal change of the drive waveform phase 1731 and a temporal change of the detection position 1732 when the reverse rotation correction function is used. In FIG. 18A and FIG. 18B, the horizontal axis is a time axis, and indicates time m1 to m13. The detection position is determined every predetermined AD conversion cycle, and the value obtained by adding the phase difference to the lower 10 bits of the detection position is output as the phase value of the drive waveform. Further, the vertical axis of each figure indicates the detection position and the drive waveform phase. The drive waveform phase 1731 and the detection position 1732 are synchronized while maintaining the phase difference of the phase difference 1702. Each time interval of time m1 to m13, that is, an interval of adjacent time corresponds to an AD conversion cycle. For the phase difference 1702, for example, −256, which is the value in S1605 of FIG. 16, is set. The arrow 1701 represents the threshold A set in S1604 of FIG.

  Here, attention is paid to a point 1723 corresponding to time m4 and a point 1724 corresponding to time m8. At these points, it is assumed that a difference amount of the rotation detection position for each AD conversion cycle exceeding the threshold A is generated due to a detection error of AD conversion, a disturbance, or the like. In FIG. 18A, since the reverse rotation correction function is not used, control is performed to synchronize the drive waveform phase 1731 while maintaining the phase difference of the phase difference 1702 with respect to the rotation detection position. Therefore, there is a possibility that the continuity of the drive waveform is lost at a location affected by the detection error of AD conversion or disturbance.

  In FIG. 18B, the CPU 111 does not maintain the phase difference 1702 with respect to the rotation detection position, and when the difference amount of the rotation detection position for each AD conversion cycle is equal to or larger than the threshold A, the situation is It is judged that it is due to the influence of detection error or disturbance. The CPU 111 controls the driving of the motor in accordance with the phase of the drive waveform obtained by adding the phase difference 1702 to the value obtained by adding the threshold A to the previous rotation detection position. For example, the CPU 111 gives the phase difference 1713 to the phase of the drive waveform at the point 1723 corresponding to the time m4, and the phase difference 1714 at the point 1724 corresponding to the time m8. As described above, during the inversion behavior, the influence of the detection error of AD conversion and the disturbance can be suppressed as much as possible, and a constant torque can be generated at all times to shorten the time until the completion of the inversion operation and stabilize the operation.

  Next, with reference to FIG. 19, a method of determining that a mechanical member connected to the motor has been forcibly moved from the outside will be described in detail. FIG. 19 is a diagram showing the time change of the drive waveform phase 1731 and the time change of the detection position 1732 when the emergency stop process is executed in S1613 of FIG. The settings of the horizontal axis and the vertical axis are the same as in FIG. 18, and the time axis indicates times m1 to m6. Each time interval from time m1 to m6 corresponds to an AD conversion cycle.

  In FIG. 19, it is assumed that a difference amount of the rotation detection position equal to or more than a predetermined value B determined in advance is generated at a point 1802 corresponding to time m5 (see an arrow 1801). At this time, even if a drive waveform in which a phase difference 1702 (see FIG. 19) is added to the rotation detection position (see point 1800) on the detection position 1732 corresponding to the point 1802 in the drive waveform phase 1731 is output. , There is a high possibility that the motor does not operate normally. The reason is that, as described in S1612, the change amount equal to or more than the predetermined value B which is the limit value is a change amount that can not occur in the motor drive system of the present embodiment. In this case, the CPU 111 determines in S1613 in FIG. 17 that, for example, a mechanical member has been forcibly moved from the outside, etc., and executes notification processing indicating that the drive state of the motor is not normal. . Then, the CPU 111 performs control to temporarily stop the drive sequence of the motor and shift to a safe restart sequence.

  Next, with reference to FIG. 20, a method of judging that a situation such as a step out of a motor or a mechanical member is forcibly fixed from the outside has occurred will be described in detail. FIG. 20 is a diagram showing the time change of the drive waveform phase 1731 and the time change of the detection position 1732 when the emergency stop process is executed in S1610 of FIG. The settings of the horizontal axis and the vertical axis are the same as in FIG. 18, and time m1 to m16 are shown on the time axis. Each time interval from time m1 to m16 corresponds to an AD conversion cycle. It is assumed that a predetermined time required for the reversing operation has elapsed at a point 1901 corresponding to time m16. At this time, there is a high possibility that the motor does not operate normally even if the drive waveform to which the phase difference 1702 is added continues to be output to the rotation detection position at the point 1902 corresponding to the point 1901. In this case, the CPU 111 determines that, for example, the motor is out of step or the mechanical member is forcibly fixed from the outside or the like, and executes a notification process indicating that the drive state of the motor is not normal. . Then, the CPU 111 performs control to temporarily stop the drive sequence of the motor and shift to a safe restart sequence.

  In this embodiment, in the reverse operation of rotating the rotor in the reverse direction, the continuity of the drive waveform is lost and the discontinuous waveform is suppressed, and the motor is efficiently applied to the motor based on the rotation detection position. A drive waveform can be generated to reduce reaction delay at that time. According to the present embodiment, it is possible to prevent the occurrence of an unintended reverse operation due to rapid deceleration based on a sudden overload or disturbance.

  The position detector of the embodiment is configured using a plurality of Hall sensors and a rotating magnet, but any other sensor mechanism may be used as long as it can be configured to detect the rotational position with high accuracy. The present embodiment has been described on the premise of the configuration of a general 10-pole claw-pole type stepping motor, but the present invention is not limited thereto. Other configurations are possible if the rotor side is a permanent magnet and the stator side is a coil stator. Is also possible.

101 Stepping motor 102 Rotor shaft 103 ENC magnet 104 Hall element package 109 Position ENC circuit 110 Drive waveform generation circuit 111 CPU
120 rotor magnets

Claims (25)

Setting means for setting the rotational direction of the rotor;
Detection means for detecting the rotational position of the rotor;
Generation means for generating a drive waveform to the motor;
Control means for performing synchronous control to synchronize the phase of the rotational position with the phase of the drive waveform;
Phase difference setting means for setting a phase difference between the rotational position and the drive waveform in a state where the phase of the rotational position and the phase of the drive waveform are synchronized;
When the direction corresponding to the change of the rotational position detected by the detection means is different from the rotational direction set by the setting means, the control means is reverse to the set rotational direction, which is the opposite direction. A motor drive device characterized by performing control which controls rotation. From the state where the first direction corresponding to the change of the rotational position detected by the detection means is the same as the second direction set by the setting means, the first direction and the second direction And when the first direction and the second direction are the same, the control means sets the phase corresponding to the maximum value of the rotational position detected by the detection means when the first direction and the second direction are the same. The motor drive device according to claim 1, wherein the drive of the motor is controlled in accordance with the phase of the drive waveform to which the phase difference by the phase difference setting means is added. The motor drive device according to claim 1 or 2, wherein the control means performs the synchronous control and the control for suppressing the reverse rotation in synchronization with the timing of detection of the rotational position by the detection means. A first direction corresponding to a change in rotational position detected by the control unit, and a second direction set by the setting unit, in a cycle related to the timing of detection of the rotational position by the detection unit. The motor drive device according to any one of claims 1 to 3, wherein it is determined whether or not the same. The said control means performs notification processing, when the said rotational position does not change over more than predetermined time during the drive of the said motor. Motor drive. The control means performs notification processing when the magnitude of the difference between the rotational position held while the motor is driven and the rotational position detected by the detection means is larger than a predetermined value. The motor drive device according to any one of claims 1 to 5, characterized in that: The motor drive device according to claim 5 or 6, wherein the control means performs the notification process, stops driving of the motor, and restarts. The detection means
First calculation means for calculating a first count value proportional to the rotation amount of the rotor;
The motor drive device according to any one of claims 1 to 7, further comprising second calculation means for calculating a second count value that periodically changes with respect to the rotation amount. The motor drive device according to any one of claims 1 to 8, wherein the detection means detects a rotational position of the rotor from a plurality of sinusoidal signals having a phase difference. The detection means calculates a tangent value from the plurality of sinusoidal signals, performs an arctangent operation on the tangent value to calculate a rotation angle of the rotor, and integrates the rotation angle to calculate the rotation position of the rotor. The motor drive device according to claim 9, wherein the information is calculated. The generation means includes phase determination means for obtaining the output of the second calculation means and determining the phase of the drive waveform.
The motor drive apparatus according to claim 8, wherein the phase difference setting means sets a steady phase difference or a driving phase difference with respect to the phase determination means. The control means is set by the phase difference setting means with reference to a phase difference between the phase corresponding to the rotational position detected by the detection means and the phase of the drive waveform when the motor is stopped. The motor drive device according to claim 11, wherein the drive of the motor is controlled in accordance with a phase difference. A motor drive method executed by a motor drive device, comprising:
A setting step of setting a rotational direction of the rotor;
Detecting the rotational position of the rotor;
A generation step of generating a drive waveform to the motor;
A control step of performing control to synchronize the phase of the rotational position with the phase of the drive waveform;
Setting a phase difference between the rotational position and the drive waveform in a state in which the phase of the rotational position and the phase of the drive waveform are synchronized,
In the control step, when the direction corresponding to the change in the rotational position detected in the detection step and the rotational direction set in the setting step are different, the set rotational direction is reverse to the opposite direction. A motor drive method characterized in that control for suppressing rotation is performed. Setting means for setting the rotational direction of the rotor;
Detection means for detecting the rotational position of the rotor;
Difference calculation means for calculating a difference between rotational positions of the rotor for each predetermined period;
Generation means for generating a drive waveform to the motor;
Control means for performing synchronous control to synchronize the phase of the rotational position with the phase of the drive waveform;
Phase difference setting means for setting a phase difference between the rotational position and the drive waveform in a state where the phase of the rotational position and the phase of the drive waveform are synchronized;
When the direction of rotation is set in the second direction opposite to the first direction by the setting means, the control means calculates the magnitude of the difference in rotational position for each predetermined period calculated by the difference calculation means. A motor drive device characterized in that control is performed to adjust the amount of rotation of the rotor when the threshold value is greater than the threshold value and smaller than the limit value. When the magnitude of the difference of the rotational position for each predetermined period calculated by the difference calculation means is greater than or equal to the threshold value and smaller than the limit value, the control means performs the rotational position detected by the detection means. The drive of the motor is controlled according to the phase of the drive waveform in which the phase difference by the phase difference setting means is added to the value obtained by adding the difference of the rotational position when it is less than the threshold. 14. The motor drive device according to 14. When the magnitude of the difference of the rotational position for each predetermined period calculated by the difference calculation means is greater than or equal to the threshold value and smaller than the limit value, the control means performs the rotational position detected by the detection means. The motor drive device according to claim 14, wherein the drive of the motor is controlled according to a phase of a drive waveform obtained by adding a phase difference by the phase difference setting means to a value obtained by adding the threshold value. The motor according to any one of claims 14 to 16, wherein the control means performs the synchronization control and the control of adjusting the amount of rotation in accordance with the timing of detection of the rotational position by the detection means. Drive device. The motor drive device according to any one of claims 14 to 17, wherein the predetermined period is a cycle related to timing of detection of a rotational position by the detection means. The threshold value is a value of a difference between rotational positions calculated by the difference calculating unit when the setting unit sets the rotational direction in the second direction, or the rotational direction in the second direction by the setting unit. It is a value determined from an average value of differences in rotational position calculated by the difference calculating means before setting, or from a difference in rotational position corresponding to the speed before the reverse operation of the rotor. The motor drive device according to any one of claims 14 to 18. After a predetermined time has elapsed since the setting of the second direction by the setting means, the control means sets the direction corresponding to the change of the rotational position detected by the detecting means, and the setting by the setting means The motor drive device according to any one of claims 14 to 19, wherein control is performed to suppress reverse rotation in the first direction when the second direction is different. 21. The control method according to any one of claims 14 to 20, wherein the control means performs notification processing when the magnitude of the difference of the rotational position for each predetermined period is equal to or greater than a predetermined value. Motor drive. 15. The control method according to claim 14, wherein the control unit performs notification processing when the magnitude of the difference of the rotational position for each predetermined period is smaller than a predetermined value even after a predetermined time has elapsed. 20. The motor drive device according to any one of 20. The motor drive device according to claim 21 or 22, wherein the control means performs the notification process, stops driving of the motor, and restarts. The motor drive device according to any one of claims 14 to 23, wherein the detection means detects a rotational position of the rotor from a plurality of sinusoidal signals having a phase difference. A motor drive method executed by a motor drive device, comprising:
A setting step of setting a rotational direction of the rotor;
Detecting the rotational position of the rotor;
A calculation step of calculating a difference between rotational positions of the rotor at predetermined intervals;
A generation step of generating a drive waveform to the motor;
A control step of performing synchronous control to synchronize the phase of the rotational position with the phase of the drive waveform;
Setting a phase difference between the rotational position and the drive waveform in a state in which the phase of the rotational position and the phase of the drive waveform are synchronized,
When the rotation direction is set in the second direction opposite to the first direction in the setting step, in the control step, the magnitude of the difference in rotational position for each predetermined period calculated in the calculation step A motor drive method characterized in that control is performed to adjust the amount of rotation of the rotor when the threshold value is greater than the threshold value and smaller than the limit value.

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