CN116540530A - A Self-tuning Method of Incremental PID Parameter Single-phase Relay Feedback for Self-decaying System - Google Patents

Abstract

The invention provides a self-tuning method for single sequential electric feedback of an incremental PID parameter of a self-attenuation system, which is different from the traditional relay feedback self-tuning method, and provides a new solution for self-tuning of the incremental PID control parameter of a self-attenuation electric drive control system which can only be controlled unidirectionally in a mobile bearing platform, thereby greatly improving the design efficiency of the control parameter and the accuracy and precision of the control. The method comprises the following steps: the system enters a single-phase sequential electric feedback self-tuning method, and the controller is switched to a single-phase relay feedback controller; the single-sequential electric feedback controller controls the system to continuously oscillate in a preset interval according to the measured value; the register records waveform data after the system generates usable waveforms; the solver calculates the optimal control quantity according to the waveform result of the register; and finally, inputting the calculated optimal control quantity into an incremental PID controller to verify whether the result meets the requirement.

Description

A Self-tuning Method of Incremental PID Parameter Single-phase Relay Feedback for Self-decaying System

technical field

The invention relates to the technical field of drive control, in particular to an incremental PID parameter single-phase relay feedback self-tuning method for a self-attenuation system.

Background technique

There are many different electric drive control systems in the mobile carrier platform. To adjust all these control parameters of a large number of electric drive systems, technicians need to have very rich theoretical knowledge and be very familiar with the parameter adjustment process. This is undoubtedly a huge amount of work and almost impossible to complete the task accurately. Due to the different working environments of the mobile load-carrying platform, such as driving on roads with different friction coefficients, braking at different ambient temperatures, and loading different targets, it is impossible for the same control parameter to adapt to such complex and changeable conditions. working conditions. Therefore, it is of great significance to design a control parameter adaptive tuning method that can adapt to various drive control systems.

The self-decaying system of one-way control refers to the system that can only input positive value control quantity in the control process and the system state will self-decay when there is no control quantity input. The traditional relay feedback method is generally used in ordinary systems that can be controlled in both forward and reverse directions, but for self-attenuating systems that can only be controlled in one direction, the traditional relay feedback method can hardly obtain correct solution results. However, the mobile carrying platform is different from the traditional relay feedback method. The mobile carrying platform can only use a self-attenuating electric drive control system with one-way control. It is a self-attenuating electric drive control system that can only be controlled in one direction. Its accelerator can only be increased. During the setting process, the deceleration depends on the self-attenuation of the driving resistance, which makes the system oscillate. Dynamic control, acceleration depends on a fixed speed, causing the system to oscillate.

Contents of the invention

The invention proposes a scheme for improving the design efficiency of control parameters and improving the precision and accuracy of control for the incremental PID control parameter self-tuning of a self-attenuating electric drive control system that can only be controlled in one direction in a mobile load-carrying platform.

The present invention provides a self-tuning method for self-attenuating system incremental PID parameter single-phase relay feedback. The self-tuning method for self-attenuating system incremental PID parameter single-phase relay feedback includes the following steps:

Step 1, the controller is transformed into a single-phase relay feedback controller, and the system parameters are initialized;

Step 2, the controller controls the system to continuously oscillate within the preset interval according to the feedback measurement value, and controls the relay on and off by comparing the measurement value with the upper and lower limits of the oscillation to make the system continuously oscillate;

Step 3, converting the oscillation waveform collected by the system into a symmetrical relay characteristic oscillation;

Step 4, after the collector obtains the available waveform data, the controller is disconnected to stop the system, and the solver calculates the ideal K _p , K _i , and K _d values according to the waveform data.

Furthermore, in step 1, the system parameters include the upper limit value of the oscillation, the lower limit value of the oscillation, the sampling period, and the maximum value of the control quantity.

Further, in step 2, the continuous oscillation of the system also includes the following steps:

Step 21, when the state quantity of the system is less than the maximum value of the preset interval, the input value x of the single-phase relay feedback controller is the difference between the preset upper limit and the measured value. According to the characteristics of the single-phase relay, the control quantity y output by the controller is is H, the self-decaying system receives positive excitation, and the system state quantity increases;

Step 22, when the system state quantity is greater than the maximum value of the preset interval, the input value x of the single-phase relay feedback controller is the difference between the preset lower limit and the measured value. According to the characteristics of the single-phase relay, the control quantity y output by the controller is 0, the self-attenuation system attenuates according to its own self-attenuation rate;

Step 23, when the system state quantity is lower than the minimum value of the preset interval, repeat steps 21 and 22, and the collector collects the time required for the rising edge of the system t ₁ , the time required for the falling edge t ₂ , and the actual system The maximum oscillation value H _max and the actual minimum oscillation value H _min of the system.

Furthermore, in step 3, the rising edge data of the oscillating waveform is obtained as a solution, and the ΔH correction amplitude is added to eliminate the influence of the self-attenuation effect on the calculation of the control variable, and the falling edge is the analog reaction after the self-attenuation effect is eliminated. To the relay control data, the oscillation period after conversion is 2t ₁ ; the correction amplitude is:

t ₁ is the time required for the rising edge, t ₂ is the time required for the falling edge, H _max is the actual maximum oscillation value of the system, and H _min is the actual minimum oscillation value of the system.

Further, in step 4, Fourier series expansion is performed on the output signal for harmonic analysis:

a ₀ represents the constant value component in the Fourier coefficient, a _n represents the amplitude of the n-fold frequency cosine component in the Fourier coefficient, b _n represents the amplitude of the n-fold frequency sine component in the Fourier coefficient, ω ₀ represents the fundamental frequency, t Indicates time, n indicates the number of Fourier series items,

When defining a sinusoidal input signal, the complex ratio of the first harmonic component in the steady-state output of the nonlinear link to the input signal is the description function of the nonlinear link, expressed by N(x):

x represents the input value, a ₁ represents the first-order cosine component of the Fourier series, and b ₁ represents the first-order sine component of the Fourier series.

Furthermore, in step 4, the relay characteristics of the controller in the self-tuning of the standard relay feedback method are:

When the relay switches at a fixed frequency, it can be seen that the input signal is regarded as a sinusoidal signal:

Among them, A is the amplitude of the output signal.

Furthermore, in step 4, in the frequency domain, when the frequency is equal to the crossover frequency, the system is in a critical state, and the theoretical value of the critical gain is:

G _p represents the system transfer function, ω _c represents the critical oscillation frequency.

When the system is critically stable, according to the Nyquist stability criterion:

G _p (jω _c )N(x)＝-1

Therefore, the critical gain and critical period of the system are:

T _u represents the critical period.

According to the obtained critical gain and critical period of the system, the control quantity of the system controller can be obtained by the Z-N method as:

_Kp = _0.6Ku

T represents the sampling period.

The beneficial effects that the present invention reaches are:

The incremental PID parameter single-phase relay feedback self-tuning method for the self-attenuating system provided by the present invention realizes the self-tuning of the PID parameters of the self-attenuating system, solves the limitation of the small application range of the traditional relay feedback PID self-tuning method, and enables Each controlled link in a complex system (such as a mobile bearing platform), especially the self-attenuation system that can only be controlled in one direction, can be adaptively tuned, which greatly improves the efficiency of complex system configuration and debugging, and improves the design efficiency and control of control system parameters. of precision.

Description of drawings

Fig. 1 is a flow chart of the tuning process of the single-phase relay feedback self-tuning method of the present invention.

Fig. 2 is a schematic diagram of system controller switching of the single-phase relay feedback self-tuning method of the present invention.

Fig. 3 is a schematic diagram of the single-phase relay feedback control of the single-phase relay feedback self-tuning method of the present invention.

Fig. 4 is a schematic diagram of waveform transformation of the single-phase relay feedback self-tuning method of the present invention.

Fig. 5 is a schematic diagram of converting the single-phase relay feedback result of the self-attenuation system into the standard relay feedback result in the single-phase relay feedback self-tuning method of the present invention.

Detailed ways

The technical solutions of the present invention will be described in more detail below in conjunction with the accompanying drawings, and the present invention includes but not limited to the following embodiments.

As shown in accompanying drawing 1, the present invention provides a kind of incremental PID parameter single-phase relay feedback self-tuning method of self-decaying system, comprising the following steps:

Step 1, the system controller is transformed into a single-phase relay feedback controller, and the definition of system parameters is initialized;

The system parameters include the upper limit of oscillation, the lower limit of oscillation, the sampling period, and the maximum value of the control quantity.

Since the self-tuning of the control parameters in the actual mobile bearing platform project needs to be carried out within a specific site range, considering the size of the site and the safety of the setting process, the upper and lower limits of the vibration cannot exceed the electronic fence range defined by the mobile bearing platform. The system can be controlled to oscillate within a safe range by setting the upper and lower limits of oscillation. The vibration range is selected in the 80% safe area outside the center of the electronic fence range, which improves the safety problems caused by the inability to estimate the vibration amplitude in the traditional relay feedback method.

Step 2, the controller controls the system to continuously oscillate within the preset interval according to the measured value fed back by the sensor, and controls the relay on and off by comparing the measured value with the upper and lower limits of the oscillation to make the system continuously oscillate;

For the standard system in which the control input of the control system in the mobile bearing platform can be positive or negative, and has no large self-attenuation tendency, the self-adaptive tuning process is directly calculated using the steps recorded in step 4.

As shown in Figure 2-3, for the self-attenuation system that can only input one-way in the mobile bearing platform, the self-attenuation control system can only be a positive value for the control input, and when the system control input is 0, the system state automatically Attenuation, manifested as a throttle system on a mobile carrying platform;

Since the control quantity input of the system can only be positive at this time, the characteristics of the single-phase relay are as follows:

x represents the input quantity of the relay, y represents the output quantity of the relay, and H represents the input of the system control quantity.

As shown in Figure 4, different from the characteristics of the standard relay process, its description function is changed accordingly, and the critical gain and critical period of the system cannot be calculated using the derivation of the standard process. In this type of system, the output of the relay is 0 when x<0, and the system has no control input and produces self-attenuation. Because the self-attenuation speed is relatively slow, the time of the rising edge and the falling edge of the system in an oscillation cycle are different, and the system cannot be converted into a single harmonic system when performing harmonic analysis on the system.

The self-tuning method provided by the present invention includes a data collector and a solver; the data collector can analyze the system waveform data, record the waveform data when the controller is input, that is, the time length of the rising part of the system, and symmetrically compensate The missing half-period length is corrected to obtain an approximate standard relay feedback characteristic waveform curve.

The solver calculates the control parameter results according to the converted waveform data, and obtains the optimal positional PID control parameters.

The continuous oscillation generation control process includes the following steps:

Step 21, when the state quantity of the system is less than the maximum value of the preset interval, the input value x of the single-phase relay feedback controller is the difference between the preset upper limit and the measured value. According to the characteristics of the single-phase relay, the control quantity y output by the controller is is H, the self-decaying system receives positive excitation, and the system state quantity increases;

Step 22, when the system state quantity is greater than the maximum value of the preset interval, the input value x of the single-phase relay feedback controller is the difference between the preset lower limit and the measured value. According to the characteristics of the single-phase relay, the control quantity y output by the controller is 0, the self-attenuation system attenuates according to its own self-attenuation rate;

Step 23, when the system state quantity is lower than the minimum value of the preset interval, repeat steps 21 and 22, and the collector collects the time required for the rising edge of the system t ₁ , the time required for the falling edge t ₂ , and the actual system The maximum oscillation value H _max and the actual minimum oscillation value H _min of the system.

Due to the obvious self-attenuation effect of the self-attenuation system, the actual results collected by the collector are non-standard relay feedback control results, which are not conducive to the calculation of the solver, so the data needs to be processed and converted into standard relay feedback control result waveform data .

Step 3, converting the oscillation waveform collected by the system into a symmetrical relay characteristic oscillation;

As shown in Figure 5, the oscillating waveform collected by the system is a waveform under the control of asymmetric relay characteristics, which is not conducive to solving the PID control parameters. Because the control amount in the actual PID control is mainly the effect of the rising edge, so the present invention mainly takes the rising edge data As a solution, ΔH is added to correct the amplitude to eliminate the influence of the self-attenuation effect on the calculation of the control quantity. The falling edge is the simulated reverse relay control data after the self-attenuation effect is eliminated, and the converted oscillation period is 2t ₁ . in:

After converting the asymmetrical relay characteristic oscillation into symmetrical relay characteristic oscillation, it enters the PID control parameter calculation link.

Step 4: After the collector obtains the available waveform data, the controller is disconnected to stop the system, and the solver calculates the ideal K _p , K _i , and K _d values according to the waveform data; among them, the available waveform is the continuous at least A periodic signal of two full cycles is produced.

The input and output of the adaptive tuning link are described as:

y=f(x)

Perform Fourier series expansion on the output signal for harmonic analysis:

a ₀ represents the constant value component in the Fourier coefficient, a _n represents the amplitude of the n-fold frequency cosine component in the Fourier coefficient, b _n represents the amplitude of the n-fold frequency sine component in the Fourier coefficient, ω ₀ represents the fundamental frequency, t Indicates time, n indicates the number of Fourier series items,

where the constant component:

T ₀ means period;

Cosine component magnitude:

Sine component magnitude:

The nth harmonic component is:

in,

If the constant value component is equal to 0 and Y _n is very small when n>1, it can be approximately considered that the sinusoidal response of the nonlinear link has only the first harmonic component:

Among them, x represents the input value, a ₁ represents the first-order cosine component of the Fourier series, and b ₁ represents the first-order sine component of the Fourier series.

It can be seen from the above derivation that when defining a sinusoidal input signal, the complex ratio of the first harmonic component in the steady-state output of the nonlinear link to the input signal is the description function of the nonlinear link, expressed by N(a):

Among them, x represents the input value.

The relay characteristics of the controller in the self-tuning of the standard relay feedback method are:

When the relay switches at a fixed frequency, it can be seen that the input signal is regarded as a sinusoidal signal:

Substitute into the description function to get:

Among them, A is the amplitude of the output signal.

In the frequency domain, when the frequency is equal to the crossover frequency, the system is in a critical state, because the step response curve of the system outputs equal-amplitude oscillations during the adaptive tuning process, and the description function of the relay coincides with the negative real part of the real axis, so the critical The frequency is equal to the crossover frequency, that is, the frequency at the intersection of the Nyquist curve of the controlled object and the negative reciprocal of the description function coincides with the crossover frequency. Therefore, the theoretical value of the critical gain is:

G _p represents the system transfer function, ω _c represents the critical oscillation frequency.

When the system is critically stable, according to the Nyquist stability criterion:

G _p (jω _c )N(a)＝-1

Therefore, the critical gain and critical period of the system are:

T _u represents the critical period.

According to the obtained critical gain and critical period of the system, the control quantity of the system controller can be obtained by the Z-N method as:

_Kp = _0.6Ku

T represents the sampling period.

Finally, input the setting results K _p , K _i , K _d into the positional PID controller and use different working conditions to verify whether the setting results can accurately control the system.

The present invention is not limited to the specific embodiments described above, and those skilled in the art can implement the present invention in various other specific embodiments according to the embodiments and the disclosure content of the accompanying drawings. Simple transformations or modified designs all fall within the protection scope of the present invention.

Claims (7)

1. a self-tuning method for self-attenuating system incremental PID parameter single-phase relay feedback, it is characterized in that, described self-attenuating system incremental PID parameter single-phase relay feedback self-tuning method comprises the following steps: Step 1, the controller is transformed into a single-phase relay feedback controller, and the system parameters are initialized; Step 2, the controller controls the system to continuously oscillate within the preset interval according to the feedback measurement value, and controls the relay on and off by comparing the measurement value with the upper and lower limits of the oscillation to make the system continuously oscillate; Step 3, converting the oscillation waveform collected by the system into a symmetrical relay characteristic oscillation; Step 4, after the collector obtains the available waveform data, the controller is disconnected to stop the system, and the solver calculates the ideal K _p , K _i , and K _d values according to the waveform data. 2. according to the self-tuning method of self-attenuation system incremental PID parameter single-phase relay feedback of claim 1, it is characterized in that, in step 1, described system parameter comprises oscillation upper limit value, oscillation lower limit value, sampling The maximum value of period and control quantity. 3. according to the described self-attenuation system incremental PID parameter single-phase relay feedback self-tuning method of claim 1, it is characterized in that, in step 2, described making system continuous oscillation also comprises the following steps: Step 21, when the state quantity of the system is less than the maximum value of the preset interval, the input value x of the single-phase relay feedback controller is the difference between the preset upper limit and the measured value. According to the characteristics of the single-phase relay, the control quantity y output by the controller is is H, the self-decaying system receives positive excitation, and the system state quantity increases; Step 22, when the system state quantity is greater than the maximum value of the preset interval, the input value x of the single-phase relay feedback controller is the difference between the preset lower limit and the measured value. According to the characteristics of the single-phase relay, the control quantity y output by the controller is 0, the self-attenuation system attenuates according to its own self-attenuation rate; Step 23, when the system state quantity is lower than the minimum value of the preset interval, repeat steps 21 and 22, and the collector collects the time required for the rising edge of the system t ₁ , the time required for the falling edge t ₂ , and the actual system The maximum oscillation value H _max and the actual minimum oscillation value H _min of the system. 4. according to the self-tuning method of self-attenuation system incremental PID parameter single-phase relay feedback self-tuning method of claim 1, it is characterized in that, in step 3, obtain described oscillating waveform rising edge data as solution, add ΔH correction amplitude value to eliminate the influence of the self-attenuation effect on the calculation of the control quantity, the falling edge is the simulated reverse relay control data after the self-attenuation effect is eliminated, and the converted oscillation period is 2t ₁ ; the correction amplitude is: t ₁ is the time required for the rising edge, t ₂ is the time required for the falling edge, H _max is the actual maximum oscillation value of the system, and H _min is the actual minimum oscillation value of the system. 5. according to the described self-attenuation system incremental PID parameter single-phase relay feedback self-tuning method of claim 1, it is characterized in that, in step 4, carry out Fourier series expansion to output signal, carry out harmonic analysis: a ₀ represents the constant value component in the Fourier coefficient, a _n represents the amplitude of the n-fold frequency cosine component in the Fourier coefficient, b _n represents the amplitude of the n-fold frequency sine component in the Fourier coefficient, ω ₀ represents the fundamental frequency, t Indicates time, n indicates the number of Fourier series items, When defining a sinusoidal input signal, the complex ratio of the first harmonic component in the steady-state output of the nonlinear link to the input signal is the description function of the nonlinear link, expressed by N(x): x represents the input value, a ₁ represents the first-order cosine component of the Fourier series, and b ₁ represents the first-order sine component of the Fourier series. 6. according to the described auto-attenuation system incremental PID parameter single-phase relay feedback self-tuning method of claim 5, it is characterized in that, in step 4, the controller relay characteristic in the standard relay feedback method self-tuning is: When the relay switches at a fixed frequency, it can be seen that the input signal is regarded as a sinusoidal signal: Among them, A is the amplitude of the output signal. 7. according to the self-tuning method of self-attenuating system incremental PID parameter single-phase relay feedback of claim 6, it is characterized in that, in step 4, in frequency domain, when frequency equals crossing frequency, system is in critical state , the theoretical value of the critical gain is: G _p represents the system transfer function, ωc represents the critical oscillation frequency; When the system is critically stable, according to the Nyquist stability criterion: G _p (jω _c )N(x)＝-1 Therefore, the critical gain and critical period of the system are: T _u represents the critical period; According to the obtained critical gain and critical period of the system, the control quantity of the system controller can be obtained by the Z-N method as: _Kp = _0.6Ku T represents the sampling period.