JP6283813B2 - Motor drive device - Google Patents

Description

  The present invention relates to a motor drive device having a function of taking a motor position from a motor position detector by serial communication and detecting a motor position at an input timing of an external input signal.

  Conventionally, a motor that takes in a motor position from a motor position detector through serial communication at the timing of a motor position latch signal generated at a constant sampling cycle, and stores the motor position at a timing when an external input signal is turned on after passing through a certain point. The drive unit stores the value of the internal counter at the timing of each edge of the motor position latch signal and the external input signal in order to increase the detection accuracy of the stored motor position. Even when the motor is turned on, the motor position at the timing when the external input signal is turned on is estimated using the stored value of the internal counter (see, for example, Patent Document 1).

  Furthermore, in order to accurately estimate the relative position even when the transmission delay time difference between two external input signals is large and the motor operates at high speed, the timing at which the external input signal is input is stored in an internal counter, and other signals Is compared with the counter value at the input timing, and estimation is performed using the difference between the counter values (see, for example, Patent Document 2).

JP 2008-220116 A JP 2010-246256 A

  The problem to be solved is that when a capacitor is used in the circuit configuration that receives an external input signal, a difference in transmission delay time appears at the rise and fall of the signal due to the difference in the operation during charge and discharge of the capacitor. , Correction according to the direction of signal change was not possible. In addition, it is necessary to input two signals for measuring the transmission delay time.

  The present invention solves the above-described conventional problems, and by inputting a rectangular wave signal with a clear duty ratio, a motor drive capable of estimating a transmission delay time difference between the rising edge and the falling edge of the signal An object is to provide an apparatus.

In order to solve the above-mentioned problem, the present invention is connected to a motor having a motor position detector for generating a motor position counter value, and the first rectangular wave edge and the first rectangular wave edge later than the first rectangular wave edge. A second rectangular wave edge that changes in the opposite direction with respect to one rectangular wave edge, and a third rectangular wave edge that changes in the opposite direction with respect to the second rectangular wave edge after the second rectangular wave edge. A motor driving device to which a rectangular wave signal having a rectangular wave edge is input, wherein the rectangular wave signal is input, and the direction is opposite to the first rectangular wave edge at the timing of the first rectangular wave edge A first external input signal edge that changes to a rectangular shape, and a second external input signal edge that changes in a direction opposite to the third rectangular wave edge at the timing of the third rectangular wave edge. Duty ratio for wave signal An input circuit that converts the rectangular wave signal into a clear external input signal, an internal counter that generates an internal counter value proportional to the motor position counter value, and a timing of the first external input signal edge Counter storage means for storing the internal counter value as a first internal counter value, and storing the internal counter value at the timing of the second external input signal edge as a second internal counter value; and the motor position Motor position capturing means for capturing a counter value as a motor control processing position counter value, the first internal counter value, the second internal counter value, the motor control processing position counter value, and the internal counter value And the motor position counter value at the timing of the second rectangular wave edge from the duty ratio To provide a motor driving device and a left position calculating means.

Explanatory drawing of the principal part of the motor drive device in Embodiment 1 of this invention. Explanatory drawing of the delay calculation means between input signals in Embodiment 1 of this invention Explanatory drawing of the detection position calculating means in Embodiment 1 of this invention The block diagram of the principal part of the motor drive device in Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
The first embodiment is a basic configuration of the present invention, and a usage example in which the motor positions at two points are detected and the relative positions thereof are accurately calculated will be described with reference to the drawings.

In FIG. 1, the motor position latch signal 18 and a rectangular wave input signal 26 with a clear duty ratio, counter storage means 12 for storing the value of the internal counter at the signal change timing of the external input signal, and external input from the motor position latch Detection position calculation means 13 for estimating the motor position change amount until the signal is turned on and calculating the motor position at the input timing of the external input signal
And the difference between the counter value obtained from the duty ratio and the internal counter value captured by the change timing of each rising or falling signal of the external input signal 24 and the other falling or rising counter value. The inter-input signal delay calculating means 16 stores as a delay correction amount, and the detection position calculating means 13 is a counter at the time of falling or rising change of the relative delay correction amount calculated by the inter-input signal delay calculating means 16. The motor driving device is configured to calculate the motor position at the input timing of the external input signal by a value subtracted from the value.

  FIG. 1 is an explanatory diagram of the main part, in which a motor 20 with a motor position detector 21 is connected to the motor drive device 10, and the motor drive device 10 uses the motor position counter value detected by the motor position detector 21. Motor position feedback control is performed by fetching the motor position fetching means 14 through the serial communication means 19 at a constant cycle (motor control cycle), inputting the value to the motor control means 15, and updating the motor control processing position counter. .

  Here, the motor position fetching means 14 has a motor timing at which the motor position latch signal 18 generated by the motor control means 15 at a constant cycle (motor control cycle) is turned on (here, Low when turned on and High when turned off). The value of the position counter is taken in.

  An external input signal 24 that turns on when the detection point of the rising edge of the signal passes and turns off when the detection point of the falling edge of the signal passes is input to the internal counter 11, the detection position calculation means 13, and the delay calculation means 16 between the input signals, Further, the motor position latch signal 18 is also inputted from the motor control means 15 to the internal counter 11.

  Here, the internal counter 11 is a 16-bit free-run counter (counting up from 0000h to FFFFh, returning to 0 and counting up again when exceeding FFFFh). The internal counter 11 counts the value of the internal counter at the timing when the input signal turns on (falling edge that changes from High to Low) or at the timing that the input signal turns off (rising edge that changes from Low to High). Copy and store (latch) in the storage means 12.

  The storage areas latched in the counter storage means 12 are differentiated for the CH0 latch register and the CH1 latch register, and for two input signals. Here, the motor position latch signal 18 is stored in the CH0 latch register, and the external input signal 24 is stored in the CH1 latch register.

  Next, the internal processing of the input signal delay calculation means 16 will be described with reference to FIG. Here, it is assumed that when a rectangular wave signal with a duty ratio of 50% is input, the logic is inverted by the input circuit, and a delay occurs in detection of the falling edge of the rectangular wave. In order to measure the transmission delay time difference between the falling input signals, the rectangular wave signal is connected to the external input signal and connected to the motor drive device 10. The signal reaches the internal counter 11 through the transmission path, and the external input signal 24 stores the internal counter value Cap1 in the CH1 latch register of the counter storage means 12 when the rising edge of the signal is detected. Next, the external input signal 24 stores the internal counter value Cap2 in the CH1 latch register of the counter storage means 12 when the falling of the signal is detected. Further, the external input signal 24 stores the internal counter value Cap3 in the CH1 latch register of the counter storage means 12 when the rising edge of the signal is detected. The inter-input signal delay calculating means 16 obtains Cap4 from the internal counter values Cap1 and Cap3 and the duty ratio.

Cap4 = (Cap1 + Cap3) × duty ratio (0.5 = 50%)
(1)
Here, the duty ratio is a ratio at which the signal is turned on (High) with respect to the period of the rectangular wave.

  Further, the difference between Cap4 and Cap2 is calculated as a relative delay correction amount.

Relative delay correction amount = Cap2-Cap4 (2)
Note that the delay shown in FIG. 2 assumes a transmission delay time due to a photocoupler or the like in the motor drive device.

  Next, the internal processing of the detection position calculation means 13 will be described using FIG. The detection position calculation process is performed at a constant cycle (motor control cycle). First, the detected position calculating means 13 takes in the latest motor position taken in by the motor position taking means 14 and stores it in the variable Pos (k). In the figure, Pos (k) is the latest value, Pos (k-1) is the value one cycle before, Pos (k-2) is the value two cycles ago, and the past motor positions are stored several times. ing. Further, the latest value of the CH0 latch register fetched by the motor position latch signal 18 from the counter storage means 12 is fetched and stored in the variable Cap0 (k). In the figure, Cap0 (k) is the latest value, Cap0 (k-1) is the value one cycle before, and Cap0 (k-2) is the value two cycles before, so the past CH0 latch register is stored several times. ing.

  The motor position Pos2 at the first falling edge detection (edge at which the external input signal 24 changes from Low to High) in FIG. 3 is obtained by the following calculation formula.

Pos2 = Pos (k− 5 ) + estimated change 1 (3)
Estimated change 1 = (Pos (k− 4 ) −Pos (k− 5 ))
× (Cap2-Cap0 (k- 5 ))
/ (Cap0 (k-4) -Cap0 (k- 5 )) (4)
Further, the motor positions Pos1 and Pos3 at the timing of the first rising edge passage and the second rising edge detection (edge at which the external input signal 24 changes from Low to High) in FIG. 3 can be obtained by the same calculation formula. Using the obtained Pos1 and Pos3 and the duty ratio of the rectangular wave, Pos4 is obtained by the method described above.

  Then, a corrected value Pr of the relative position between the first falling edge passing point and the first falling edge detection point is obtained by the following calculation formula.

Pr = Pos2-Pos4 (5)
Data indicating detection of the relative position Pr and the falling edge calculated by the detection position calculation means 13 is output as a monitor value 23 through the motor control means 15. The host device can know the relative positional relationship between the falling edge detection and the falling edge detection with reference to the monitor value 23.

  With this configuration, in a motor control system that takes in the motor position from the motor position detector via serial communication and performs feedback control, the motor position is accurately estimated even when the external input signal transmission delay is large and the motor operates at high speed. can do.

(Embodiment 2)
The second embodiment shows the method for switching the state between the measurement mode and the correction mode of the present invention, and provides a mode for measuring the relative delay time and a mode for calculating (correcting) using the measured relative delay time. ing. After measuring the relative delay time described in the first embodiment in the measurement mode, returning to the mode for calculating using the measured relative delay time makes it possible to perform correction according to the detected change in the external signal.

  By this mode switching, the measurement timing and the reflection timing become clear, so that the relative delay time can be measured and reflected only by the motor drive device, and the correction processing of the host device is not necessary.

(Embodiment 3)
The third embodiment is an application configuration of the present invention, and is provided with a parameter storage unit 17 for storing the relative delay correction amount calculated by the inter-input signal delay calculation unit 16. Since the parameter storage unit 17 is a non-volatile storage unit, it retains a value even when the power source of the motor driving device is reset. After resetting the power of the motor driving device, the detection position calculation means 13 can read out the relative delay correction amount from the parameter storage means 17 and can reuse it, and the recalculation of the relative delay correction amount can be omitted.

  This configuration eliminates the need for work (input signal wiring switching) performed during the relative delay correction amount calculation process, and improves usability. In addition, in the motor drive device 10 in which the parameter storage unit 17 has already been mounted for other uses, it is not necessary to add hardware, and an increase in cost can be suppressed.

  It is assumed that the motor control means 15, the detection position calculation means 13, and the inter-input signal delay calculation means 16 are processed by a microcomputer or the like.

  The motor drive device of the present invention is also useful for devices that measure the width of an object at the rise and fall of a signal.

DESCRIPTION OF SYMBOLS 10 Motor drive device 11 Internal counter 12 Counter memory | storage means 13 Detection position calculating means 14 Motor position taking-in means 15 Motor control means 16 Delay calculation means between input signals 17 Parameter memory means 26 Rectangular wave input signal with clear duty ratio

Claims (4)

Connected to a motor having a motor position detector for generating a motor position counter value, the first rectangular wave edge and opposite to the first rectangular wave edge after the first rectangular wave edge A rectangular wave signal having a second rectangular wave edge that changes and a third rectangular wave edge that changes in a reverse direction with respect to the second rectangular wave edge after the second rectangular wave edge is input. A motor drive device,
A first external input signal edge that is input with the rectangular wave signal and changes in a direction opposite to the first rectangular wave edge at the timing of the first rectangular wave edge, and the third rectangular wave edge An input for converting the rectangular wave signal into an external input signal having a second external input signal edge that changes in a direction opposite to the third rectangular wave edge at a timing and a clear duty ratio with respect to the rectangular wave signal Circuit,
An internal counter for generating an internal counter value proportional to the motor position counter value;
The internal counter value at the timing of the first external input signal edge is stored as a first internal counter value, and the internal counter value at the timing of the second external input signal edge is stored as a second internal counter value. Counter storage means for storing as:
Motor position capturing means for capturing the motor position counter value as a position counter value for motor control processing;
From the first internal counter value, the second internal counter value, the motor control processing position counter value, the internal counter value, and the duty ratio, at the timing of the second rectangular wave edge Detection position calculation means for obtaining the motor position counter value;
Comprising
Motor drive device. The motor position capturing means captures the motor position counter value as the motor control processing position counter value at the predetermined period,
The detected position calculation means stores the motor control processing position counter value and the internal counter value at each fixed period.
The motor drive device according to claim 1. The external input signal is a third external input signal edge that changes in an opposite direction with respect to the first external input edge between the first external input signal edge and the second external input signal edge. Further comprising
The counter storage means stores the internal counter value at the timing of the third external input signal edge as the third internal counter value;
The detection position calculation means calculates the motor position counter value at the timing of the third external input signal edge from the third internal counter value, the motor control processing position counter value, and the internal counter value. Ask,
The motor drive device according to claim 1. A delay calculation means between input signals for obtaining an internal counter value at the timing of the second rectangular wave edge from the first internal counter value, the second internal counter value, and the duty ratio;
The motor drive device according to claim 1.

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