JPH07281708A - Autotuning controller - Google Patents

Abstract

PURPOSE:To decide a control parameter for featuring the operational characteristics of a controlled system without being limited by the operational pattern of a real machine to which a servo motor is fitted. CONSTITUTION:When a vibration amplitude alpha and a vibration frequency (x) of real velocity are estimated from the real position of a controlled system 2 (the position of the servo motor) to be detected by a position sensor 3 and the vibrating state of the controlled system 2 is decided from that estimated vibration amplitude alpha while a velocity command for stopping the controlled system is applied from a stop instruction part 9 to a velocity control part 7, a velocity control parameter is adjusted so that the vibration amplitude alpha can get lower than a previously set value. Concretely, when the vibration frequency (x) is lower than a fixed rate in comparison with a frequency fs of sampling time at the velocity control part 7, the velocity control parameter is gradually enlarged but when the vibration frequency (x) is higher than the fixed rate in comparison with the frequency fs, the velocity control parameter is gradually reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tuning controller for automatically adjusting various controlled objects having different characteristics and controlled objects having varying characteristics.

[0002]

2. Description of the Related Art In a conventional auto-tuning controller, in auto-tuning for determining control parameters related to speed control, a servo motor is actually operated by a step command or the like to estimate the characteristics of a controlled object, and its operation characteristics are The control target is estimated from the (speed response) to determine the control parameter (Japanese Patent Laid-Open No. 3-2681).
No. 02).

[0003]

However, in the above-mentioned auto-tuning, the operation pattern (constant speed time, acceleration / deceleration time, rotation direction, rotation amount, etc.) set in order to obtain the operation characteristic of the controlled object is limited. However, since the operation pattern when the servo motor is actually used in the actual machine is different, auto tuning may not be applied after the servo motor is actually attached to the actual machine.

The present invention has been made based on the above circumstances, and its object is to control parameters for characterizing the operating characteristics of a controlled object without being limited by the operating pattern of the actual machine to which the servo motor is attached. The object is to provide an auto-tuning controller capable of determining.

[0005]

In order to achieve the above object, the present invention employs the following technical means for each claim. According to a first aspect of the present invention, there are provided position detecting means for detecting the position of the controlled object, a speed command output section for outputting a speed command for stopping the controlled object, and a speed control parameter characterizing the speed control characteristic of the controlled object. By using the deviation between the actual speed of the controlled object obtained from the detection value of the position detection means and the speed command output from the speed command output unit, a current command necessary to stop the controlled object is obtained. A speed control unit for performing a feedback, a current control unit for feedback-controlling a current for stopping the controlled object based on the current command, and whether the controlled object is in a stationary state or vibrates based on a detection value of the position detection unit. And a determination unit that determines whether the control target is in a state, and when the determination target determines that the control target is in a vibration state, the vibration frequency becomes a preset frequency. Is optionally less than the fixed percentage of the speed control parameter is the larger, the case vibration frequency is equal to or greater than the rate constant for the set frequency,
And a speed control parameter adjusting unit that reduces the speed control parameter.

According to a second aspect of the present invention, in the auto tuning controller according to the first aspect, the speed control parameter adjusting section obtains the speed control parameter when the determining means determines that the controlled object is in a stationary state. The maximum value that can be obtained.

According to another aspect of the present invention, there is provided a position detecting means for detecting the position of the controlled object, a speed command output section for outputting a speed command for stopping the controlled object, and a speed characterizing the speed control characteristic of the controlled object. Using the control parameter, the deviation between the actual speed of the controlled object obtained from the detection value of the position detection means and the speed command output from the speed command output unit is necessary to stop the controlled object. A speed control unit that issues a current command, a current control unit that feedback-controls a current for stopping the control target based on the current command, and a current detection unit that detects a current flowing from the current control unit to the control target. And a torque calculation for calculating a torque required to stop the controlled object based on the detection value of the position detection means and the detection value of the current detection means. A step, a determining means for determining whether the control target is in a stationary state or a vibrating state based on the torque calculated by the torque calculating means, and the determining means determines that the control target is in a vibrating state. And a speed control parameter adjusting section that determines the speed control parameter so that the ripple of the torque calculated by the torque calculating means is minimized.

According to a fourth aspect of the present invention, in the auto tuning controller according to the third aspect, the speed control parameter adjusting section obtains the speed control parameter when the determining means determines that the controlled object is in a stationary state. The maximum value that can be obtained.

According to a fifth aspect of the present invention, in the auto tuning controller according to the first or second aspect, a position command output section that outputs a position command for stopping the controlled object and a position that characterizes the position control characteristic of the controlled object. Using a control parameter, the speed command necessary for stopping the controlled object is output to the speed control unit by the deviation between the detected value of the position detection unit and the position command output from the position command output unit. If the vibration frequency is smaller than a predetermined ratio to a preset frequency when it is determined that the controlled object is in a vibrating state by the position control unit and the determining unit, the position control parameter is set to If the vibration frequency is higher than a certain ratio with respect to the set frequency, the position control parameter for decreasing the position control parameter is increased. And a chromatography data adjustment unit.

According to a sixth aspect of the present invention, in the auto tuning controller according to the fifth aspect, the position control parameter adjusting section obtains the position control parameter when the determining means determines that the controlled object is in a stationary state. The maximum value that can be obtained.

According to a seventh aspect of the present invention, in the auto tuning controller according to the third or fourth aspect, a position command output section for outputting a position command for stopping the controlled object and a position characterizing the position control characteristic of the controlled object. Using a control parameter, the speed command necessary for stopping the controlled object is output to the speed control unit by the deviation between the detected value of the position detection unit and the position command output from the position command output unit. And a position control unit that determines the position control parameter so that the ripple of the torque calculated by the torque calculation unit is minimized when the control unit determines that the controlled object is in a vibrating state. And a parameter adjusting unit.

According to an eighth aspect of the present invention, in the auto tuning controller according to the seventh aspect, the position control parameter adjusting section obtains the position control parameter when the determining means determines that the controlled object is in a stationary state. The maximum value that can be obtained.

[0013]

According to the present invention as set forth in claim 1, the determination means determines whether the controlled object is in the stationary state or in the vibrating state while the speed command for stopping the controlled object is output. When it is determined that the controlled object is in the oscillating state, the controlled object can be in the stationary state by adjusting the speed control parameter based on the vibration frequency. Specifically, when the vibration frequency is lower than a predetermined ratio with respect to the preset frequency, the speed control parameter is increased by the speed control parameter adjustment unit so that the vibration frequency is equal to or higher than the predetermined ratio with respect to the set frequency. In the case of, the speed control parameter is reduced.

According to the third aspect of the present invention, the torque required to stop the controlled object is calculated, and it is determined whether the controlled object is in the stationary state or the vibrating state based on this torque. When it is determined that the controlled object is in a vibrating state, the speed control parameter is determined so that the amplitude of torque is minimized.

According to a fifth aspect of the present invention, after the speed control parameter is determined according to the first or second aspect, when the determining means determines that the controlled object is in a vibrating state, its vibration frequency is set in advance. If it is smaller than a fixed ratio to the set frequency, the position control parameter is increased by the position control parameter adjusting unit, and if the vibration frequency of the controlled object is a fixed ratio or more to the set frequency, the position control parameter is adjusted. To reduce.

According to a seventh aspect of the present invention, after the speed control parameter is determined according to the third or fourth aspect, when the determination means determines that the controlled object is in a vibrating state, the torque amplitude is the minimum. The position control parameter is determined so that

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the auto tuning controller of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing the configuration of the auto tuning controller.

The auto-tuning controller 1 of this embodiment includes a position sensor 3 attached to a controlled object 2, a power-on sequence control section 4, an operation pattern command section 5, a position control section 6, a speed control section 7, and a current. The control unit 8, the stationary command unit 9, the vibration frequency estimation unit 10, the torque estimation unit 11, the vibration pulse determination unit 12, the auto tuning unit 13 and the like are incorporated. The controlled object 2 includes a servomotor (not shown) and a load attached to the motor shaft of the servomotor.

The position sensor 3 is a position detecting means for detecting the actual position of the controlled object 2, and specifically, a rotary encoder attached to a servo motor can be used. It should be noted that this rotary encoder can determine the rotation direction by generating pulses having different phases by 90 °, and can determine the origin by obtaining an output of one pulse for one rotation. .

When the power is turned on, the power-on sequence controller 4 self-diagnoses whether there is any abnormality in the auto-tuning controller 1, and during that time, the controlled object 2 does not operate according to a command from the operation pattern commander 5. As described above, the switch 14 in the auto tuning controller 1 is switched to the stationary command section 9 side (position a in the figure) to bring the controlled object 2 into the stationary state. The switch 14 is selectively switched between the stationary command unit 9 side and the position control unit 6 side (position b in the drawing).

The operation pattern command section 5 is a language or a signal by which the auto tuning controller 1 can interpret a user program (operation command program of the controlled object 2) created by a user using a personal computer, an operation panel or the like in a specialized language. To a position control unit 6 via a switch 15 for a position to be moved in the unit of time every certain fixed sampling time.
The switch 15 is located on the side of the stationary command unit 9 (position a in the figure).
And the operation pattern command unit 5 side (position b in the figure).

The position control unit 6 determines the deviation between the position command output from the stationary command unit 9 or the motion pattern command unit 5 at every constant sampling time and the actual position of the controlled object 2 fed back from the position sensor 3. The PI control is performed using the current position control parameter, and the speed command is given to the speed control unit 7.

The speed control section 7 outputs the actual speed obtained by differentiating the actual position of the controlled object 2 fed back from the position sensor 3 by the differentiating operator 16 and the stationary command section 9 or the position control section 6. Based on the deviation from the speed command, the current speed control parameter (correctly, parameters called speed proportional gain, speed integral gain, speed differential gain) is used for PID control, and the current command is given to the current controller 8. .

The current control unit 8 is preset by the control target 2 from the deviation between the actual current fed back from the current sensor 17 for detecting the current actually flowing to the servo motor and the current command from the speed control unit 7. The PI control is performed using the current control parameter and the current is applied to the servo motor.

The stationary instruction unit 9 gives a speed command and a position command for stopping the controlled object 2 to the speed control unit 7 and the position control unit 6, respectively, during the self-diagnosis.

The vibration frequency estimation unit 10 takes in the actual position of the controlled object 2 fed back from the position sensor 3 and estimates the vibration frequency and vibration amplitude of the actual speed and the actual position.

The torque estimation unit 11 takes in the actual current fed back from the current sensor 17 and the actual position of the controlled object 2 fed back from the position sensor 3, and obtains the current electric current of the servomotor obtained from the actual position. The torque required to make the controlled object 2 stationary is estimated from the angle and the actual current. The torque can be calculated based on the following formula.

[0028]

## EQU1 ## TRQ = KT × ia / sin θ where TRQ = estimated torque, KT = torque constant, ia =
Real current, θ = motor electrical angle.

The vibration pulse judgment unit 12 (judgment means of the present invention) takes in the vibration frequency estimated by the vibration frequency estimation unit 10 and the estimated torque estimated by the torque estimation unit 11 to determine the current state of the controlled object 2. It is determined whether it is completely stationary or vibrating, and if vibrating, the vibration cycle is detected. However, it is necessary to consider the quantum error of the position sensor 3 (rotary encoder) when determining whether the controlled object 2 is in a stationary state or a vibrating state. Therefore, when the vibration amplitude α of the actual speed or the estimated torque is smaller than the preset value, it is determined that the vibration does not occur.

The auto tuning unit 13 determines (adjusts) the speed control parameter and the position control parameter based on the determination result of the vibration pulse determination unit 12.

Next, the operation for determining the speed control parameter and the position control parameter will be described based on the flowchart shown in FIG. Power on (step S
After 1), the switch 14 is switched to the stationary command unit 9 side (step S2). As a result, the auto tuning controller 1 makes the controlled object 2 stand still based on the speed control parameter updated when the power was last turned on. However, if the power is turned on for the first time this time, the initial value (default value) stored in advance in the auto tuning controller 1 is used as the speed control parameter.

In this state, in the speed control unit 7, the actual speed obtained by differentiating the actual position of the controlled object 2 fed back from the position sensor 3 and the speed command from the stationary command unit 9 (in this case, it becomes 0). ) And PID control is performed using the current speed control parameter, and a current command necessary for stopping the controlled object 2 is given to the current control unit 8.

The current control unit 8 uses a preset current control parameter based on the deviation between the current command from the speed control unit 7 and the actual current detected by the current sensor 17 to set P
I control is performed, and a current for stopping the controlled object 2 is applied.

Subsequently, the actual current detected by the current sensor 17 and the actual position detected by the position sensor 3 are fetched into the torque estimation unit 11, and the current electric angle and actual current of the servo motor obtained from the actual position are obtained. Thus, the torque required to make the controlled object 2 stationary is estimated (step S3). Further, the actual position detected by the position sensor 3 is fetched into the vibration frequency estimation unit 10 to determine the vibration amplitude α and the vibration frequency x of the actual speed (step S3).

Then, the vibration pulse judging section 12 judges whether the current state of the controlled object 2 is a completely stationary state or vibrating (step S4). In this determination, when the vibration amplitude α of the actual speed (or torque) is smaller than a preset value, it is judged that the vibration does not occur. When the vibration amplitude α is equal to or larger than the preset value, the vibration state is Judge that there is.

Then, the determination result of step S4 is YES.
In the case of, that is, when it is determined that the controlled object 2 is in the vibrating state, it is determined whether the vibration frequency x is smaller than a certain ratio with respect to the frequency fs of the sampling time at which the speed control unit 7 controls. (Step S5). If the determination result is YES, that is, if the vibration frequency x is smaller than a certain ratio with respect to the frequency fs (x / fs <A),
The speed control parameter is gradually increased by the auto-tuning unit 13 until the vibration amplitude α of the actual speed becomes equal to or less than the set value (until it is determined in step S4 that the vehicle is in the stationary state) (step S6).

When the result of the determination in step S5 is NO, that is, when the vibration frequency x is equal to or higher than a certain ratio with respect to the frequency fs (x / fs ≧ A), the vibration amplitude α of the actual speed is set. The speed control parameter is gradually reduced by the auto-tuning unit 13 until the value becomes equal to or less than the predetermined value (until the determination means of step S4 determines that the vehicle is in a stationary state) (step S7).

If the result of the determination in step S4 is NO, that is, if it is determined that the controlled object 2 is in the stationary state, whether or not the speed control parameter is the maximum value that the controlled object 2 can take in the stationary state. Is determined (step S8). If this determination result is NO, that is, if it is determined that the speed control parameter is not the maximum value, the speed control parameter is increased until it reaches the maximum possible value (step S9).

The maximum speed control parameter determined by the auto tuning unit 13 is updated as a speed control parameter used by the speed control unit 7 and used as a control parameter at the time of command operation by the operation pattern command unit 5.

After updating the speed control parameters, the switch 14 is switched to the position control section 6 side, and the switch 15 is switched to the stationary command section 9 side (step S1).
0), the controlled object 2 is stopped.

Next, the actual current detected by the current sensor 17 and the actual position detected by the position sensor 3 are fetched into the torque estimation unit 11, and the current electric angle and actual current of the servo motor obtained from the actual position are obtained. Thus, the torque required to make the controlled object 2 stationary is estimated (step S11). Further, the actual position detected by the position sensor 3 is taken into the vibration frequency estimation unit 10 to determine the vibration amplitude β and the vibration frequency y at the actual position (step S11).

Subsequently, the vibration pulse judging section 12 judges whether the current state of the controlled object 2 is a completely stationary state or vibrating (step S12). If this determination result is YES, that is, if it is determined that the controlled object 2 is in a vibrating state, the vibration frequency y is smaller than a fixed ratio with respect to the frequency fp of the sampling time at which the position control unit 6 controls. It is determined whether or not (step S13).

When the result of this determination is YES, that is, when the vibration frequency y is smaller than a certain ratio with respect to the frequency fp (y / fp <B), the vibration amplitude β at the actual position becomes the set value or less. Until (until it is determined to be in a stationary state in step S12), the position control parameter is gradually increased by the auto tuning unit 13 (step S1).
4).

When the result of the determination in step S13 is NO, that is, when the vibration frequency y is equal to or higher than a certain ratio with respect to the frequency fp (y / fp ≧ B), the vibration amplitude α at the actual position is set. The position control parameter is gradually decreased by the auto-tuning unit 13 until the value becomes equal to or less than the predetermined value (until it is determined by the determination means in step S12 that the vehicle is in a stationary state) (step S15).

If the decision result in the step S12 is NO, that is, if it is decided that the controlled object 2 is in the stationary state, whether or not the position control parameter is the maximum value that can be taken in the stationary state of the controlled object 2. Is determined (step S16). If the determination result is NO, that is, if it is determined that the position control parameter is not the maximum value, the position control parameter is increased until it reaches the maximum possible value (step S17).

The maximum position control parameter determined by the auto tuning unit 13 is updated as a position control parameter used by the position control unit 6 and used as a control parameter at the time of command operation by the operation pattern command unit 5.

After that, at the same time when the power-on sequence control unit 4 determines that the auto tuning controller 1 is ready, the switch 15 is switched to the operation pattern command unit 5 side (the switch 14 remains on the position control unit 6 side. (Step S18)), and the operation is started by the instruction of the operation pattern instruction unit 5.

[Modification] In the present embodiment, the optimum values of the speed control parameter and the position control parameter were obtained from the vibrations of the actual speed and the actual position, but based on the data obtained by the torque estimation unit 11 at each stage, It is also possible to obtain the torque ripple γ and determine the speed control parameter and the position control parameter so that the ripple γ is minimized.

[0049]

The auto-tuning controller of the present invention is limited to the operation pattern of the actual machine to which the servo motor is attached by adjusting the speed control parameter and the position control parameter while the servo motor is stationary (stationary command state). It is possible to determine the optimum speed control parameter and position control parameter in a short period of time without having to do so.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an auto tuning controller.

FIG. 2 is a flowchart showing the operation of this embodiment.

[Explanation of symbols]

1 Auto Tuning Controller 2 Control Target 3 Position Sensor (Position Detecting Unit) 6 Position Control Unit 7 Speed Control Unit 8 Current Control Unit 9 Standstill Command Unit (Speed Command Output Unit, Position Command Output Unit) 11 Torque Estimating Unit (Torque Calculating Unit) ) 12 vibration pulse determination unit (determination unit) 13 auto-tuning unit (speed control parameter adjustment unit, position control parameter adjustment unit) 17 current sensor (current detection unit)

Claims (8)

[Claims] 1. A) position detecting means for detecting a position of a controlled object, b) a speed command output section for outputting a speed command for stopping the controlled object, and c) a speed control characteristic of the controlled object. By using a speed control parameter to characterize, the control target is stopped by the deviation between the actual speed of the control target obtained from the detection value of the position detection means and the speed command output from the speed command output unit. A speed control unit that issues a current command required for the following: d) a current control unit that feedback-controls the current for stopping the controlled object based on the current command; and e) based on the detection value of the position detection means. Determining means for determining whether the controlled object is in a stationary state or a vibrating state; and f) when the determining object determines that the controlled object is in a vibrating state, its vibration frequency is The speed control parameter is increased when the ratio is smaller than a fixed ratio with respect to the set frequency, and the speed control parameter is decreased when the vibration frequency is equal to or higher than the fixed ratio with respect to the set frequency. An auto tuning controller equipped with a speed control parameter adjustment unit. 2. The auto-tuning controller according to claim 1, wherein the speed control parameter adjusting unit has a maximum value that can be used as the speed control parameter when the determining unit determines that the control target is in a stationary state. An auto-tuning controller characterized by 3. A position detecting means for detecting a position of a controlled object, b) a speed command output section for outputting a speed command for stopping the controlled object, and c) a speed control characteristic of the controlled object. By using a speed control parameter to characterize, the control target is stopped by the deviation between the actual speed of the control target obtained from the detection value of the position detection means and the speed command output from the speed command output unit. A speed control unit that issues a current command necessary for the following: d) a current control unit that feedback-controls the current for stopping the controlled object based on the current command; and e) a current that flows from this current control unit to the controlled object. A current detecting means for detecting an electric current; and f) calculating a torque required to stop the controlled object based on the detected value of the position detecting means and the detected value of the current detecting means. G) torque determining means, and g) determining means for determining whether the control target is in a stationary state or a vibrating state based on the torque calculated by the torque calculating means, and h) the control target in this determining means. Is determined to be in a vibrating state, the speed tuning parameter adjusting unit determines the speed controlling parameter so that the ripple of the torque calculated by the torque calculating unit is minimized. 4. The auto-tuning controller according to claim 3, wherein the speed control parameter adjusting unit has a maximum value that can be taken by the speed control parameter when the determining unit determines that the control target is in a stationary state. An auto-tuning controller characterized by 5. The auto tuning controller according to claim 1, further comprising a position command output unit that outputs a position command for stopping the controlled object, and a position control parameter that characterizes the position control characteristic of the controlled object. A position control for outputting a speed command necessary for stopping the controlled object to the speed control unit based on a deviation between a detected value of the position detection unit and the position command output from the position command output unit. Part, when it is determined that the control target is in a vibration state by the determination means, if the vibration frequency is smaller than a predetermined ratio to a preset frequency, increase the position control parameter, A position control parameter adjusting unit that reduces the position control parameter when the vibration frequency is equal to or higher than a certain ratio with respect to the set frequency. Auto-tuning controller, comprising the. 6. The auto-tuning controller according to claim 5, wherein the position control parameter adjusting unit has a maximum value that can be taken by the position control parameter when the determining unit determines that the control target is in a stationary state. An auto-tuning controller characterized by 7. The auto tuning controller according to claim 3, further comprising a position command output unit that outputs a position command for stopping the controlled object, and a position control parameter that characterizes a position control characteristic of the controlled object. A position control for outputting a speed command necessary for stopping the controlled object to the speed control unit based on a deviation between a detected value of the position detection unit and the position command output from the position command output unit. And a position control parameter adjustment unit that determines the position control parameter so that the ripple of the torque calculated by the torque calculation unit is minimized when the control unit determines that the controlled object is in a vibrating state. An auto tuning controller characterized by having and. 8. The auto-tuning controller according to claim 7, wherein the position control parameter adjusting unit has a maximum value that can be taken as the position control parameter when the determining unit determines that the control target is in a stationary state. An auto-tuning controller characterized by