JP2017049637A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a control device that detects the controlled variable of a control object on the basis of a signal from the control object, performs control arithmetic using a deviation of the detected controlled variable from the target value, and generates a control signal to eliminate the deviation to be configured by a PLD having a small logic count.SOLUTION: A control device 1 comprises a speed detection unit 11 for detecting the revolution speed of a motor 3 on the basis of a signal from the motor, a manipulated variable calculation unit 12 for calculating a manipulated variable so as to eliminate a deviation between the detected revolution speed and an intended revolution speed, and a PWM conversion unit 13 for generating a PWM signal that is a control signal of the motor 3 on the basis of input from the calculation unit 12. The manipulated variable calculation unit 12 performs the arithmetic of expression X when calculating a manipulated variable at the n'th time in cases when n is a positive integer. Expression X: U=U+G×e-G×e+G×e, where Uis a manipulated variable at the n'th time, eis a deviation at the n'th time, and G, G, Gare gains.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control device, and more particularly to a control device that generates a control signal so as to eliminate a deviation between a detected control amount of a control target such as a motor and a target value.

  PID (Proportional-Integral-Derivative) control is widely used for controlling the rotation of a motor (for example, an inner brushless motor) used in an image forming apparatus. PID control is a type of feedback control, and is a control in which control of a motor control signal is performed by three elements of proportionality, integration, and differentiation with respect to a deviation from a target value of the motor. In the case of a motor, the deviation from the target value is the difference between the target value and the control amount (speed or position) of the motor based on the signal from the encoder added to the motor.

When a motor control signal is generated by performing a PID calculation using a deviation by a CPU (Central Processing Unit), a high-performance CPU is required, and a peripheral circuit for inputting a signal from the encoder to the CPU is required. Thus, an expensive circuit configuration is required, and a program for controlling the CPU is complicated.
When a motor control program is ported to another model (different CPU), it takes a long time to debug a program.

  In connection with the above points, Patent Document 1 calculates a carriage speed based on a signal input from an encoder of a carriage drive motor of an inkjet printer, and a PWM (Pulse Width Modulation) signal which is a control signal of the motor. A control device comprising a hard logic circuit for generating The hard logic circuit of this control device generates a control signal based on a predetermined operation amount input from the CPU during acceleration and deceleration of the carriage drive motor. When the carriage reaches a constant speed, a deviation from the target value is obtained. The operation amount is calculated by the PID calculation, and the control signal is generated based on the operation amount. The hard logic circuit of Patent Document 1 is, for example, an ASIC (Application Specific Integrated Circuit).

  In Patent Documents 2 and 3, a carriage moving speed is detected based on a signal from an encoder, and a PID calculation is performed based on a difference between a target speed and the detected speed to generate a motor control signal. A control device is disclosed. Patent Documents 2 and 3 disclose that the control device is composed of a programmable logic device such as an ASIC or CPLD (Complex Programmable Logic Device) or FPGA (Field Programmable Gate Array).

Japanese Patent Laid-Open No. 10-66374 JP 2003-186544 A JP 2003-186545 A

  However, the control device disclosed in Patent Document 1 requires a plurality of complement operations for the PID calculation used to calculate the control signal. In the control devices disclosed in Patent Documents 2 and 3, the PID operation includes integral and differential operations. is necessary.

  The present invention has been made in view of the above situation, and detects a control amount of a control target based on an input signal from a control target such as a motor, and also detects a deviation of the detected control amount from a target value. Is a control device that generates a control signal that eliminates the deviation, and can be configured with a hardware logic device. It is an object of the present invention to provide a device that performs a new control calculation that does not require calculation and differentiation.

In order to solve the above-described problem, the first technical means of the present invention includes a detection unit that detects a control amount of the control target based on a signal input from the control target, and a detection unit that detects the control amount. An operation amount calculation unit that calculates an operation amount so as to eliminate a deviation between the control amount and the target value, and generates a control signal of the control target based on an input from the operation amount calculation unit, and the generated control signal is A control signal generation unit that inputs to the operation target, and when the operation amount calculation unit calculates n for the nth operation amount when n is a positive integer, Perform the operation of A,
_{U n = G A × U n} -1 + (1-G A) × U n-2 + G C × e n -G D × e n-1 + G E × e n-2
... (Formula A)
U _n is the n-th of the operation amount, the e _n the deviation of the _{n-th, G A, G C, G} D, G E is obtained by being a gain.

A second technical means of the present invention is characterized in that _GA is 1 in the first technical means.

According to a third technical means of the present invention, in the second technical means, the operation amount calculation unit outputs the operation amount by limiting the calculated operation amount to a limit value or less. If it is the limit value or more, it is obtained by and performs the calculation using the limit value as U _n-1.

According to a fourth technical means of the present invention, in the second or third technical means, Gc, G _D , and G _E are integers, and the operation amount calculation unit calculates the number of bits of the result of the operation as the control signal. It is characterized by having a bit shift unit that performs bit shift to the number of bits required for the input value of the generation unit.

According to a fifth technical means of the present invention, in any one of the first to fourth technical means, the control signal generation unit determines the control amount based on a target value when the control device is activated. The control signal is generated based on a fixed value until the switching value is reached, and after the switching value is reached, switching is performed so as to generate the control signal based on an input from the operation amount calculation unit, The operation amount calculation unit performs the calculation from before the switching, sets the deviation to zero and fixes the calculation result at a value corresponding to the target value until the switching, and the formula after the switching in the calculation of a, in which the G _a for using the actual deviation, using actual operation result as the result of the operation was characterized by a 1.

According to a sixth technical means of the present invention, in the fifth technical means, the detection unit counts a cycle of a pulse corresponding to a rotation state of the motor output from an encoder included in the motor to be controlled with a clock. The rotation speed is detected based on a conversion table in which the number of clocks and the rotation speed that is the control amount of the motor are associated, and after a predetermined time has elapsed after the start of the start, the G _a to start the detection of the rotational speed is obtained by being a 1.

  According to a seventh technical means of the present invention, in any one of the first to fourth technical means, the control signal generation unit is output from an encoder included in the motor to be controlled from the start of activation of the control device. The control signal based on the fixed value is generated until the pulse edge count corresponding to the rotation state of the motor is detected a predetermined number of times, and after the predetermined number of times is detected, the operation amount calculation unit Switching is performed so as to generate the control signal based on an input.

  An eighth technical means of the present invention is the technical means according to any one of the first to seventh aspects, further comprising a deceleration unit that decelerates the rotation of the motor to be controlled, wherein the control signal generation unit is the operation amount calculation unit. In response to the input of the deceleration instruction of the control target during a period in which the control signal based on the operation amount input from is input, the deceleration unit starts the deceleration of the rotation of the control target, and the operation After the quantity calculation unit performs the calculation with the deviation as zero, the control signal generation unit generates a control signal corresponding to the target value, and causes the deceleration unit to start decelerating rotation of the control target In response to the fact that the control amount detected by the detection unit has reached a predetermined value corresponding to the target value, the deceleration unit stops the deceleration of the rotation of the control target, and the operation amount calculation unit The calculation is performed using the actual deviation, and the control is performed. Signal generating section is obtained by and generates a control signal based on input from the operation amount calculation unit.

  According to a ninth technical means of the present invention, in any one of the first to eighth technical means, the ninth technical means comprises a hardware logic device.

  According to the present invention, the control amount of the control target is detected based on the input signal from the control target such as a motor, and the calculation using the deviation of the detected control amount with respect to the target value is performed to eliminate the deviation. A control device that generates a simple control signal that can be configured with a hardware logic device and performs a new operation that does not require multiple complement calculations, integral calculations, and differential calculations as calculations using the above deviation can do.

It is a figure which shows an example of the control apparatus which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating an example of the speed detection method in the speed detection part of FIG. It is a figure which shows an example of the conversion table referred when the speed detection part of FIG. 1 detects a speed. It is a figure for demonstrating an example of the speed detection method in the speed detection part of FIG. It is a figure which shows the structural example of the operation amount calculation part of FIG. It is a figure which shows the other structural example of the operation amount calculation part of FIG. It is a figure which shows an example of the control apparatus which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the subject of the control apparatus using PID control. It is a figure for demonstrating the other subject of the control apparatus using PID control. It is a figure for demonstrating operation | movement of the control apparatus of FIG. 7 until a motor settles. It is another figure for demonstrating operation | movement of the control apparatus of FIG. 7 until a motor settles. It is a figure which shows an example of the control apparatus which concerns on the 3rd Embodiment of this invention.

  Hereinafter, preferred embodiments of the control device of the present invention will be described with reference to the drawings. In the following inventions, the same reference numerals in different drawings are the same, and the description thereof may be omitted.

(First embodiment)
FIG. 1 is a diagram illustrating an example of a control device according to the first embodiment of the present invention.
The control device 1 in FIG. 1 is intended to control a motor 3 and is composed of a hardware logic device such as an ASIC, CPLD, or FPGA.
The control device 1 includes a speed detection unit 11, an operation amount calculation unit 12, and a PWM conversion unit 13. The feedback control executed by the control device 1 is not continuous time control but discrete time control (digital control) operating with a predetermined clock.

  The CPU 2 inputs the target rotation speed as the target value of the motor 3 to the operation amount calculation unit 12. In the control device 1, after receiving the target rotation speed and the start trigger from the CPU 2, the speed control of the motor is completed by the control device 1 alone without using the CPU 2.

  The motor 3 is, for example, an inner brushless motor, and the rotor 32 is rotated by a drive voltage applied from the motor driver 31. The encoder 33 of the motor 3 outputs two-channel encode signals ENCODE_A and ENCODE_B composed of pulse signals indicating the current rotation state of the motor 3 to the speed detection unit 11 of the control device 1.

2-4 is a figure for demonstrating an example of the speed detection method in the speed detection part 11. FIG.
The speed detection unit 11 of the control device 1 is an example of the “detection unit” of the present invention, and based on the two-channel encode signals ENCODE_A and ENCODE_B input from the encoder 33 of the motor 3 to be controlled. Calculate / detect speed. As a speed detection method, as shown in FIG. 2, a method of counting one cycle of each encoded signal with a clock and detecting the rotational speed at that time from the counted value is conceivable.

When the rotation speed is SPD (unit: rpm), the clock frequency is EPI_CLK (unit: MHz), and the count number of one cycle is EPI_CT, the rotation speed SPD can be expressed by the following equation (1).
SPD = (EPI_CLK / (EPI_CT × encoder resolution)) × 60 × 10 ⁶
... Formula (1)

  It is unrealistic to execute the operation (division) of the above formula (1) in the logic circuit. Therefore, the speed detection unit 11 stores in advance a conversion table as shown in FIG. 3 in which the number of clocks is converted into speed in a ROM (Read Only Memory) (not shown), and this table is used for speed detection. refer.

  As shown in FIG. 4, the speed detection unit 11 uses the clock to set intervals of the rising edge of the encode signal ENCODE_A, the falling edge of the encode signal ENCODE_A, the rising edge of the encode signal ENCODE_B, and the falling edge of the encode signal ENCODE_B. Count independently and update the count as each edge is observed.

Returning to the description of FIG.
The operation amount calculation unit 12 of the control device 1 eliminates the deviation between the target rotational speed input from the CPU 2 and the motor speed detected by the speed detection unit 11 input from the speed detection unit 11. Is calculated.

  The PWM conversion unit 13 is an example of the “control signal generation unit” of the present invention, converts the input from the operation amount calculation unit 12 into a PWM signal that is a control signal of the motor 3, and outputs the PWM signal to the motor driver 31.

Next, the control calculation performed in the operation amount calculation unit 12 of the control device 1 will be described.
The transfer function in PID control can be expressed by the following equation 2 when the trapezoidal rule is used for the calculation method of the integral output and the calculation method of the differential filter output. In Equation 2, P, I, and D are independent gains, T _S is a sampling time, and N is a filter coefficient.

When Equation 2 is transformed into a difference equation, it can be expressed by Equation 3 below. In Expression 3, n is a positive integer, the U _n n-th manipulated variable, e _n is the n-th _{deviation, G A, G C, G} D, G E is the gain.
_{U n = G A × U n} -1 + (1-G A) × U n-2 + G C × e n -G D × e n-1 + G E × e n-2
... (Formula 3)

  The operation amount calculation unit 12 calculates the operation amount by performing the control calculation of Equation 3 above. The control calculation of Equation 3 does not require a plurality of complement calculations, integral calculations, differential calculations, and the like.

During control operation of the above formula 3, it is preferable that the gain G _A is 1. By the gain G _A is 1, the equation 3 becomes Equation 4 below.
_{U n = U n-1 +} G C × e n -G D × e n-1 + G E × e n-2
... (Formula 4)
The formula 4, as compared with the above equation 3, the multiplication and the gain G _A, since calculation of the U _n-2 is not required, it can be simpler circuit.

Furthermore, the gains G _C , G _D , and G _E are preferably integers. This is because if it is not an integer, it is difficult to configure with a hardware logic device. The gains G _C , G _D , and G _E are determined from simulation or the like, are stored in advance, and can be changed from the outside.

FIG. 5 is a diagram illustrating a configuration example of the operation amount calculation unit 12.
The operation amount calculation unit 12 in FIG. 5 includes a deviation generation unit 110 and a calculation unit 120.
Deviation generator 110 generates a deviation e _n is the difference between the rotational speed V _act of the motor 3 which is input from the target speed V _tgt and the speed detector 11 is input from the CPU 2.
The calculation unit 120 is a logical form of the above-described Expression 4. The calculation unit 120 includes a first delay unit 121, a first amplification unit 122, a second amplification unit 123, a second delay unit 124, a third amplification unit 125, a third delay unit 126, a fourth amplification unit 127, and an addition unit 128. Have

The first delay unit 121 outputs the input value after delaying the input value by a predetermined time. The predetermined time is equal to the update cycle / operation cycle of the manipulated variable U _n. In the example shown, the input value to the first delay unit 121, an output value U _n of the adder 128. Therefore, the output value of the first delay unit 121 in the calculation of the _nth operation amount Un is the (n-1) th operation amount _Un-1 .

The first amplifying unit 122 amplifies and outputs the input output value of the first delay unit 121. Gain of the first amplifier 122 (gain) is G _A. Here G _A is 1. Therefore, the first amplification unit 122 can be omitted. The output value of the first amplifying unit 122 in the calculation of the _nth operation amount Un is the (n-1) th operation amount _Un-1 .

Second amplifier 123 amplifies and outputs the deviation e _n is input from the deviation generator 110. The gain of the second amplifying unit 123 is G _C. the output value of the second amplifier 123 in the calculation of the n-th manipulated variable U _n is a G _C × e _n.

The second delay unit 124 outputs the deviation e _n is input from the deviation generator 110 by a predetermined time delay. The delay time of the second delay unit 124 is the same as the delay time of the first delay unit 121, an update period of the manipulated variable U _n. The output value of the second delay unit 124 in the calculation of the _nth operation amount Un is an (n-1) th deviation en _-1 .

The third amplifying unit 125 amplifies and outputs the deviation en _-1 input from the second delay unit 124. Gain of the third amplifying unit 125 is G _D. The output value of the third amplifying unit 125 in the calculation of the _nth manipulated variable Un is G _D × en ₋₁ .

The third delay unit 126 outputs the deviation e _n is input from the deviation generator 110 by a predetermined time delay. The delay time of the third delay unit 126 is twice the delay time of the first delay unit 121, is twice the update cycle of the manipulated variable U _n. the output value of the third delay unit 126 in the calculation of the n-th manipulated variable U _n is a n-2 th of the deviation e _n-2.

The fourth amplifying unit 127 amplifies and outputs the deviation en _-2 input from the third delay unit 126. Gain of the fourth amplifying portion 127 is a G _E. The output value of the fourth amplifying unit 127 in the calculation of the _nth manipulated variable Un is G _E × en ₋₂ .

Adding unit 128, the output value of the first amplifying unit 122, the output value of the second amplifier 123 adds the output value and the output value of the fourth amplifying portion 127 of the third amplification unit 125, the operation amount U _n Output. However, the adding unit 128 multiplies the output value of the third amplifying unit 125 by minus 1, and then adds them.

FIG. 6 is a diagram illustrating another configuration example of the operation amount calculation unit 12.
There is no particular problem in setting the gain G _A to 1. However, when the gains G _C , G _D , and G _E are integers, when these gains have a desired accuracy (for example, 8 bits), When the output value is directly input to the PWM conversion unit 13, the accuracy required for the input value of the PWM conversion unit 13, that is, a very large value compared to the number of bits. Therefore, it is preferable that the operation amount calculation unit 12 includes a bit shift unit 130 that bit-shifts the output value from the calculation unit 120 as shown in FIG. The bit shift unit 130 performs bit shift on the input value and outputs it. The bit shift amount of the bit shift unit 130 is determined by the number of bits of the input value and the number of bits necessary for the PWM conversion unit 13.

The gain G _C, G _D, when these gains and desired accuracy (e.g., 8 bits) in the case where the G _E and an integer, and the output value from the calculating unit 120 directly inputted to the bit shift unit 130, a bit Since the shift amount is large, the number of logic becomes large. In order to suppress the bit shift amount, it is preferable that the operation amount calculation unit 12 includes a first limiting unit 140 that is a limiter. The first limiting unit 140 limits the input value to a predetermined limit value or less and outputs it.

For example, the limit values in the first limiter 140 are as follows.
Here, when the driving voltage of the motor 3 and V _m, the limit value of the first limiting portion 140 = PWM duty ratio of 100% = satisfy the relationship of V _m.
Multiply the target rotational speed by the accuracy of the desired gain.
The multiplication value is divided by a predetermined value represented by a power of 2. The predetermined value is obtained by simulation or the like.
The nearest power value of 2 that is equal to or greater than the division value is set as the limit value of the first limiter 140.

If the gain accuracy is 256 (8 bits), the target rotation speed is 2500, and the predetermined value is 8, the multiplication value is 256 × 2,500 = 640,000, and the division value is 640,000 / 8 = 80,000, and the limit value is 131,072 (2 ¹⁷ ).
In this case, if the accuracy required for the input value of the PWM conversion unit 13 is 10 bits (1024), the bit shift amount in the bit shift unit 130 is 7 bits.

By providing the first restriction unit 140, the output from the calculation unit 120 may be different from the output from the operation amount calculation unit 12. Therefore, when the output from the calculation unit 120 is directly input to the first delay unit 121, feedback control cannot be performed appropriately.
Therefore, it is preferable to apply the technique described in Japanese Patent Application No. 2015-68792 filed by the present applicant and provide the second restriction unit 150 in the operation amount calculation unit 12. The second limiting part 150 is input from the operation unit 120, i.e., the manipulated variable U _n input from the addition section 128, and outputs the limited below a predetermined limit value. For example, the limit value L2 of the second limiter 150 and the limit value L1 of the first limiter 140 are the same. Therefore, the output value of the first delay unit 121 in the calculation of the _nth operation amount U _n is the (n−1) th operation amount U when the (n−1) th operation amount U _n−1 is smaller than the limit value L2. _{When n-1} is large, the limit value L2 is output.

(Second Embodiment)
FIG. 7 is a diagram illustrating an example of a control device according to the second embodiment of the present invention. 8 and 9 are for explaining the problem of the control device using PID control.
Even with a conventional control device, the target speed can be obtained by PID control. However, if PID control is performed from the stop state of the motor, the motor will actually rotate even if the output duty is input due to the influence of the electrical next constant, etc. There is a time lag until. Therefore, as shown in FIG. 8, since the PID calculation result, that is, the feedback amount is accumulated and the output duty continues to be much larger than the output duty X in the static state, the detected speed exceeds the target rotational speed V _tgt , so-called _overshoot. The shoot becomes very large and takes time to settle. In order to suppress overshoot, there is a method of adjusting the PID gain such as the integral gain low. However, this method has a demerit that the rise time Ta that is the time until the target rotational speed V _tgt is reached becomes very long.

In addition, a method has been proposed in which the motor is driven with a fixed output until a switching speed set to a predetermined ratio of the target speed is reached, and switching to PID control after reaching the switching speed. In this method, it is possible to shorten the time until stabilization as compared with the case where the PID control is performed from the stopped state of the motor. However, in this method, as shown in FIG. 9, when switching from fixed duty to PID control after reaching the switching speed V _S , the calculated duty is “0”, so the output duty is also “0%”. The rise time Ta becomes long.

The control device 4 in FIG. 7 is for shortening the above-described rise time and time until establishment, and is characterized by the operation at the time of activation.
The control device 4 includes a fixed output unit 44 and an output selection unit 45 in addition to the speed detection unit 41, the operation amount calculation unit 42, and the PWM conversion unit 43.

The speed detector 41 calculates / detects the rotational speed of the motor 3 in the same manner as the speed detector 11 of FIG. The speed detection unit 41 outputs the detected speed to the operation amount calculation unit 42 and the output selection unit 45.
The operation amount calculation unit 42 calculates the operation amount by performing the control calculation of the above-described Expression 4 in the same manner as the operation amount calculation unit 12 of FIG.
The fixed output unit 44 outputs a predetermined fixed value.

The PWM conversion unit 43 converts the input from the operation amount calculation unit 42 or the fixed output unit 44 into a PWM signal that is a control signal of the motor 3 and outputs the PWM signal to the motor driver 31.
The output selection unit 45 selects which of the operation amount calculation unit 42 and the fixed output unit 44 is input to the PWM conversion unit 43 based on the rotation speed of the motor 3 from the speed detection unit 41. The output selection unit 45 inputs the output from the fixed output unit 44 to the PWM conversion unit 43 until the rotation speed of the motor 3 becomes a switching speed described later, and calculates the operation amount after the rotation speed of the motor 3 becomes the switching speed. The output from the unit 42 is input to the PWM conversion unit 43. .
The switching speed is determined in order to determine the timing for switching the control of the motor 3 from the fixed value control based on the output of the fixed output unit 44 to the feedback control based on the output of the operation amount calculation unit 42. It is predetermined according to the speed, and is, for example, 95% of the target rotational speed of the motor 3.

  10 and 11 are diagrams for explaining the operation of the control device 4 until the motor 3 is settled. FIG. 10 is a diagram illustrating the time change of the motor rotation speed and the output duty in the control device of the comparative example that performs an operation different from that of the control device 4. FIG. 11 is a diagram showing temporal changes in the motor rotation speed and the output duty in the control device 4 of FIG.

Control device of the comparative example, as shown in FIG. 10, the motor control fixed value until the switching speed V _S, after becoming switching speed V _S, the fixed value control, the control operation of Equation 4 above The control is switched to the feedback control used, and the control calculation is performed before the switching. In the control device of the comparative example, since the control calculation results are accumulated, the output duty immediately after switching to the feedback control becomes very large and may reach 100%. Therefore, a large overshoot occurs, and it takes a long time to settle.

On the other hand, the control device 4 is the same as the control device of the comparative example in that the switching is performed from the fixed value control to the feedback control after the switching speed V _S and the control calculation is performed before the switching. It differs from the comparative example in the following points. That is, in the control device 4, in the control calculation before the switching to the feedback control, the operation amount calculation unit 42 sets the deviation to zero and fixes the calculation result at a value corresponding to the target rotational speed V _tgt. The calculation differs from the comparative example in that an actual deviation is used as the deviation. The value corresponding to the target rotational speed V _tgt is a value when the target rotational speed V _tgt is settled by feedback control, and is determined in advance.
The control calculation before switching to feedback control is started immediately after startup, for example, and a value corresponding to the target speed V _tgt can be output at the time when switching to feedback control is performed.

  Therefore, in the control device 4, what is input to the PWM conversion unit 43 immediately after switching from the fixed value control to the feedback control is a value corresponding to the target speed output by the operation amount calculation unit 42, After switching, after the normal control calculation using the actual deviation as the deviation is completed, the calculation result is input to the PWM conversion unit 43.

In the control device 4, by performing the control calculation and output as described above, the output duty immediately after the motor speed becomes the switching speed V _S and the control is switched from the fixed value control to the feedback control as shown in FIG. 11. However, since the result of the control calculation is neither accumulated nor 0, overshoot does not occur, and it does not take a long time to settle.

Further, in the control device 4, the speed detection unit 41 does not detect the rotation speed of the motor 3 immediately after the start of the start, but performs the fixed value control during a predetermined time after the start of the start. May be.
Since the number of clocks of one cycle of the encode signal from the motor 3 and the rotational speed of the motor 3 are in an inversely proportional relationship, as is apparent from FIG. Many things are included. Therefore, as described above, the rotation speed of the motor 3 is not detected until the predetermined time has elapsed after the start of starting, that is, the speed detection in the low speed region is not performed, so that Since the information in the low speed region is not necessary, the conversion table can be made small and the ROM capacity for storing the conversion table can be greatly reduced. For example, in the example of FIG. 3, the ROM capacity can be halved if information less than 270 rpm is unnecessary, and the ROM capacity can be ¼ if information less than 540 rpm is not needed.

  The fixed output control is divided into two stages, and a high fixed value is input to the PWM conversion unit 43 until the motor 3 starts to move, and a low fixed value is input to the PWM conversion unit 43 after the motor 3 starts moving. Also good.

(Third embodiment)
FIG. 12 is a diagram illustrating an example of a control device according to the third embodiment of the present invention.
The control device 5 of FIG. 12 is characterized by the operation at the time of activation, similar to the control device 4 of FIG. 7, and includes a speed detection unit 51, an operation amount calculation unit 52, a PWM conversion unit 53, a fixed output unit 54, and an output selection unit. In addition to 55, an encoder edge counter 56 is provided.

The speed detector 51 calculates / detects the rotational speed of the motor 3 in the same manner as the speed detector 11 of FIG. The speed detection unit 51 outputs the detected speed to the operation amount calculation unit 52.
The operation amount calculation unit 52 calculates the operation amount by performing the control calculation of the above-described Expression 4 in the same manner as the operation amount calculation unit 12 of FIG.
The fixed output unit 54 outputs a predetermined fixed value.

The PWM conversion unit 53 converts the input from the operation amount calculation unit 52 or the fixed output unit 54 into a PWM signal that is a control signal of the motor 3 and outputs the PWM signal to the motor driver 31.
The encoder edge counter 56 counts the edges of the two-channel encode signals ENCODE_A and / or ENCODE_B input from the encoder 33 of the motor 3, and outputs the edge count number after activation to the output selection unit 55. .

  The output selection unit 55 selects which output of the operation amount calculation unit 52 and the fixed output unit 54 is input to the PWM conversion unit 53 based on the information of the edge count number from the encoder edge counter 56. The output selection unit 55 causes the output from the fixed output unit 54 to be input to the PWM conversion unit 53 until the edge count reaches a predetermined number, and after the predetermined number of times, the output from the operation amount calculation unit 52 is output. Is input to the PWM converter 53.

  Therefore, in the control device 5, the rise time to the target rotational speed is longer than that in the control device 4 in FIG. 7, but it is possible to shorten the time until the settling time compared to the case where the PID control is performed immediately after the start of activation. it can. Further, the control device 5 is more resistant to disturbance than the control in which the fixed output continues for a long time because the period of the feedback control based on the output from the operation amount calculation unit 12 is long. If the predetermined number of times is 1, these effects become remarkable.

  Further, when the predetermined number is a plurality of times, it is not necessary to detect the rotational speed of the motor 3 until it is observed a plurality of times, so the information on the low speed region in the conversion table of FIG. The conversion table can be made small, and the ROM capacity for storing the conversion table can be greatly reduced.

(Fourth embodiment)
In the control device of the present embodiment, the operation amount calculation unit performs the control calculation of the above-described Expression 4 as in the first to third embodiments, and the patent application filed by the present applicant for the operation at the time of deceleration. The technique described in Japanese Patent No. 2015-68792 is applied.

Specifically, the control device of the present embodiment includes a speed reduction unit that decelerates rotation of the motor to be controlled, in addition to the speed detection unit, the operation amount calculation unit, and the PWM conversion unit similar to those in the first to third modes And has a normal mode and a deceleration mode.
In the normal mode, the operation amount calculation unit calculates the operation amount by performing a control calculation using an actual deviation based on the output from the speed detection unit, and the PWM signal conversion unit outputs the operation amount output from the operation amount calculation unit. A PWM signal is generated based on the above.
When an instruction to make the target rotational speed smaller than the current rotational speed is input during operation in the normal mode, the control device of the present embodiment shifts to the deceleration mode, and the deceleration unit starts decelerating the rotation of the motor. In the deceleration mode, the operation amount calculation unit performs the control calculation of the above-described equation 4 with a deviation of 0, and the PWM conversion unit generates a PWM signal corresponding to the target rotation speed. Then, after the reduction of the rotation of the motor by the reduction unit is started, the control device of the present embodiment receives the fact that the rotation speed of the motor has reached a predetermined value corresponding to the target rotation speed. Stop the deceleration of rotation and return to the normal mode.

  With this configuration, it is possible to suppress the occurrence of overshoot and undershoot during deceleration control.

  In the first to fourth embodiments, in a state where the speed is stabilized, that is, in a constant speed range, the speed detection unit uses a moving average for speed detection. For example, the speed detection unit detects the speed by a simple moving average of the latest four times in the constant speed region. In the acceleration region and deceleration region such as at the time of startup, the speed detection unit detects the speed without using the moving average. This is because when the moving average is used in the acceleration region and the deceleration region, separation from the actual speed is large.

DESCRIPTION OF SYMBOLS 1, 4, 5 ... Control apparatus, 2 ... CPU, 3 ... Motor, 4 ... Control apparatus, 5 ... Control apparatus, 11, 41, 51 ... Speed detection part, 12, 42, 52 ... Operation amount calculation part, 13, 43, 53 ... PWM converter, 31 ... Motor driver, 32 ... Rotor, 33 ... Encoder, 44, 54 ... Fixed output part, 45, 55 ... Output selector, 56 ... Encoder edge counter, 110 ... Deviation generator, DESCRIPTION OF SYMBOLS 120 ... Operation part 121 ... 1st delay part 122 ... 1st amplification part 123 ... 2nd amplification part 124 ... 2nd delay part 125 ... 3rd amplification part 126 ... 3rd delay part 127 ... 1st 4 amplification units, 128... Addition unit, 130... Bit shift unit, 140... First restriction unit, 150.

Claims (9)

A detection unit that detects a control amount of the control target based on a signal input from the control target;
An operation amount calculation unit that calculates an operation amount so as to eliminate a deviation between the control amount detected by the detection unit and the target value;
A control signal generation unit that generates a control signal of the control target based on an input from the operation amount calculation unit, and inputs the generated control signal to the operation target;
The operation amount calculation unit performs an operation of Expression A when calculating the operation amount for the nth time when n is a positive integer.
_{U n = G A × U n} -1 + (1-G A) × U n-2 + G C × e n -G D × e n-1 + G E × e n-2
... (Formula A)
U _n is the nth operation amount,
e _n is the n-th deviation,
_A control apparatus characterized in that G _A , G _C , G _D , and G _E are gains. G _A control device according to claim 1, characterized in that the 1. The operation amount calculation unit is to output by limiting the calculated manipulated variable to the limit value or less, when n-1-th operation amount is equal to or larger than the limit value, utilizing the limit value as U _n-1 The control device according to claim 2, wherein the calculation is performed. Gc, G _D and G _E are integers,
The said operation amount calculation part has a bit shift part which bit-shifts the bit number of the result of the said calculation to the bit number calculated | required by the input value of the said control signal generation part, The Claim 2 or 3 characterized by the above-mentioned. Control device. The control signal generation unit generates the control signal based on a fixed value until the control amount becomes a predetermined switching value based on a target value when the control device is started up, and becomes the switching value. After that, switching to generate the control signal based on the input from the operation amount calculation unit,
The operation amount calculation unit performs the calculation from before the switching, sets the deviation to zero and fixes the result of the calculation at a value according to the target value until the switching, and the formula after the switching 5. The control device according to claim 1, wherein an actual deviation is used in the calculation of A and an actual calculation result is used as a result of the calculation. The detector is
The pulse period corresponding to the rotation state of the motor output from the encoder of the motor to be controlled is counted with a clock,
The rotation speed is detected based on a conversion table in which the number of clocks and the rotation speed that is the control amount of the motor are associated with each other.
6. The control device according to claim 5, wherein the detection of the rotational speed is started after a predetermined time has elapsed after the start of the activation.   The control signal generator is fixed from the start of activation of the control device until a pulse edge count corresponding to the rotation state of the motor output from the encoder of the motor to be controlled is detected a predetermined number of times. The control signal based on a value is generated, and after the predetermined number of times is detected, switching is performed so as to generate the control signal based on an input from the operation amount calculation unit. 5. The control device according to any one of 4. A speed reduction unit that decelerates rotation of the motor to be controlled;
In response to the input of the deceleration instruction of the control target during a period in which the control signal generation unit generates a control signal based on the operation amount input from the operation amount calculation unit,
The deceleration unit starts decelerating rotation of the controlled object;
The manipulated variable calculation unit performs the calculation with the deviation as zero,
The control signal generation unit generates a control signal according to the target value;
After starting the deceleration of the rotation of the controlled object in the deceleration unit, the control amount detected by the detection unit has become a predetermined value corresponding to the target value,
The deceleration unit stops the deceleration of the rotation of the controlled object;
The operation amount calculation unit performs the calculation using an actual deviation,
The control device according to claim 1, wherein the control signal generation unit generates a control signal based on an input from the operation amount calculation unit. The control device according to claim 1, comprising a hardware logic device.

Images