A fast, high-precision, high-stability self-adaptive force source control method and system

Abstract

The application discloses a kind of fast high-precision high-stability self-adaptive force source control method and system, by the loading process is divided into linear uniform velocity loading, deceleration loading, stable control loading three sections, in linear uniform velocity loading stage, the loading stage proportion and speed are freely set to achieve load quickly and efficiently reach target load nearby, in deceleration loading stage, in combination with instantaneous structure stiffness, target load distance and self-adaptive safety factor, so that load quickly and stably enters target load stable range, in PID stable control stage, instantaneous stiffness matrix is used as influencing factor to PID control;Using the method can realize the fast, accurate, stable loading of load.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automatic control, and relates to a fast, high-precision and high-stability self-adaptive force source control method and system. BACKGROUND

[0002] Servo motor control systems are widely used in industrial automation, robotics, aerospace and other fields, for precise position control, speed control or force control. These systems usually include sensors, actuators, controllers and feedback loops, etc. components, through continuous adjustment of the output of the controller to achieve precise control of the motor and other actuators. For some specific applications, such as precision machining or precise positioning, higher control accuracy and stability are required, and traditional control methods may not meet the needs; and the servo motor system itself may have nonlinearity and time-varying, and traditional control methods are difficult to effectively handle these complexities.

[0003] Existing solutions for servo motor control systems include traditional PID control, fuzzy control, neural network control, model predictive control, etc. These methods can achieve precise control of the motor to some extent, but still have some shortcomings, for example: PID control is simple and easy to implement, but its control ability for complex systems and nonlinear systems is limited, and often needs to be tuned to obtain better performance; fuzzy control can handle nonlinear systems, but the design of fuzzy rules and the determination of fuzzy sets are subjective, and are easily affected by environmental changes; while neural network control can adapt to nonlinear systems and fuzzy systems, but network structure design and training require a large amount of data, and the black box nature makes it difficult to explain and debug.

[0004] In summary, existing technologies often fail to achieve fast, high-precision, high-stability control of servo systems in mechanical loading. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a fast, high-precision and high-stability self-adaptive force source control method and system.

[0006] The technical solution adopted by the present application is as follows:

[0007] A fast, high-precision and high-stability self-adaptive force source control method, comprising dividing the self-adaptive loading process into three stages: linear uniform loading stage, deceleration loading stage and PID stable control stage; wherein:

[0008] The linear uniform loading stage involves freely setting the loading speed based on the working conditions, maximizing the loading speed as much as possible when conditions permit, and freely setting the proportion of this stage. After completing the uniform loading stage, the deceleration loading stage begins. By combining the instantaneous stiffness matrix at the time of entering the deceleration stage, the distance to the target load state, and the adaptive safety factor, the deceleration speed curve is adjusted and controlled in real time to achieve the goal of reaching the target load stability range without load overshoot. When the load reaches the target load stability range, the PID stabilization control stage begins, with the instantaneous stiffness matrix at this moment acting as an influencing factor in the PID control.

[0009] In the above technical solution, further, the target payload F is obtained. D The difference between the initial load F0 and the initial load F0 is taken as F. Δ And set the proportion γ of the remaining load to be applied after the linear uniform loading stage is completed, and determine the loading speed of this linear uniform loading stage as follows:

[0010]

[0011] Where K is the stiffness, V1 is determined by minimizing T1 under the premise of satisfying the working condition, and it is used as the loading speed for this stage. The cumulative load in this linear uniform loading stage is (1-γ)F. Δ .

[0012] Furthermore, based on the remaining load γF after the uniform loading phase is completed... Δ Determine the required speed V1 during the deceleration and loading phase, specifically including:

[0013] Based on the remaining load and uniform deceleration, the total displacement is calculated as follows:

[0014]

[0015] K R This represents the instantaneous stiffness matrix at the moment of entering the deceleration loading phase;

[0016] Therefore, it can be calculated that if uniform deceleration is used, the corresponding deceleration must satisfy:

[0017] V1 2 =2aS

[0018] That is:

[0019] a = V1 2 / 2S=V1 2 K / 2γF Δ

[0020] An adaptive factor is added to the uniform deceleration to prevent load overshoot, that is, the deceleration is adaptively corrected in real time by replacing V1 with V:

[0021]

[0022] Wherein, S1 is the total displacement amount of this stage, S t is the instantaneous displacement amount, loading is carried out according to the speed strategy until the current loading load reaches β·F D Wherein, β is a preset control coefficient, then enters the PID stable control stage.

[0023] Further, entering the PID stable control stage, the target of the displacement control is to minimize the error, i.e. the difference between the actual displacement and the expected displacement of the system.

[0024] Further, first, the kp, ki and kd parameters are dimensionless processed, in each cycle, the instantaneous structural stiffness of the loaded material needs to be estimated according to the load and displacement information fed back by the force sensor and displacement sensor in the loading platform, and returned to the PID control equation as the control parameter, and the above process is repeated to realize the self-optimization process of the PID control system:

[0025]

[0026] Wherein, error(t) is the difference between the actual displacement and the expected displacement of the system, Ks is the instantaneous structural equivalent stiffness at the time of entering the PID control stage, kp, ki and kd are the dimensionless processed equivalent control constants, ΔF is the instantaneous load change amount, and Δl is the instantaneous displacement change amount.

[0027] A fast, high-precision and high-stability self-adaptive force source control system, comprising: a loading device module, a loading system parameter acquisition module and a self-adaptive loading configuration module.

[0028] The loading device module is used to execute the loading process of the target load or target displacement, and contains a pulse signal emitting device and a servo driver for axial force loading or torsion.

[0029] The loading system parameter acquisition module is used to acquire the parameters generated by the system during the loading process, and contains a pulse signal acquisition system and a loading device load acquisition sensor; the pulse signal emitting device emits pulse signals to the servo driver, and the pulse signal acquisition system records the frequency and quantity of the pulse signals, and calculates the speed information V and displacement information S of the servo driver, and the loading device load acquisition sensor is used to obtain real-time load information during the loading process.

[0030] The self-adaptive loading configuration module calculates and updates the parameter configuration information for loading according to the information acquired by the loading system parameter acquisition module by using the self-adaptive force source control method of any one of the above.

[0031] The beneficial effects of the present application are at least:

[0032] In the control method of the present application, the loading process is divided into three stages: linear uniform loading, deceleration loading, and PID stable control loading. The rapid, accurate and stable loading of the load can be realized. Specifically:

[0033] In the linear uniform loading stage, the loading speed and the proportion of the linear stage can be freely set, so that the load can quickly and efficiently reach the target load range. This process can be freely controlled according to the loading speed and the proportion of the linear stage.

[0034] In the deceleration loading stage, the instantaneous structural stiffness, target load distance and adaptive safety factor are considered in the loading process, so that the load can quickly and stably enter the target load stable range, and the curve slope tends to be horizontal, and the load overshoot phenomenon will not occur. This process can be controlled according to the adaptive safety factor.

[0035] In the last PID stable control stage, compared with the PID stable control algorithm of full intervention or the PID stable control algorithm of loading end intervention, the loading process has already greatly tended to be flat when entering the target load stable range, so that the load shock will not occur basically, and the load stability can be achieved very quickly. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The adaptive loading process in the method of the present application is shown in the figure;

[0037] Figure 2 The PID control system principle diagram in the method of the present application is shown in the figure;

[0038] Figure 3 The single-axis continuous loading and unloading effect diagram is shown in the figure. DETAILED DESCRIPTION

[0039] The technical solutions of the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0040] The adaptive force source control method of the present application divides the adaptive loading process into three stages: linear uniform loading stage, deceleration loading stage and PID stable control stage. For example, Figure 1As shown, the linear uniform loading stage can be freely set according to the working condition, the loading speed is as high as possible under the condition, and the stage ratio can be freely set, so that the loading efficiency can be improved; the deceleration loading stage, that is, when the uniform loading stage is completed, the deceleration stage is entered, and the deceleration state speed curve depends on the instantaneous stiffness matrix when the deceleration stage is entered, the distance from the target load state and the adaptive safety factor, that is, the deceleration curve is adjusted in real time, so that the target load stable range can be efficiently and stably reached, and the load overshoot phenomenon does not occur; when the load reaches the target load stable range, that is, the PID stable control stage, the instantaneous stiffness matrix at this moment is used as an influencing factor to the PID control algorithm, the PID control algorithm at this moment has a targeted control parameter and starts to control the loading process to be stable, and due to the curve stable transition brought by the previous deceleration stage, the PID control algorithm can realize the stability control of the load in a very short time, and the load shock basically does not occur, and the next loading stage can be rapidly entered.

[0041] The method can realize corresponding functions based on the following system, which comprises a loading device module, a loading system parameter acquisition module and an adaptive loading configuration module; wherein: the loading device module is used for executing the loading process of the target load or target displacement, and comprises a pulse signal transmitting device and a servo driver for shaft force loading or torsion; the loading system parameter acquisition module is used for acquiring the parameters generated by the system during the loading process, and comprises a pulse signal acquisition system and a loading device load acquisition sensor; the pulse signal transmitting device is a numerical control device for transmitting pulse command signals to the servo driver, and the frequency and quantity of the pulse signals represent the speed and displacement or the rotation speed and rotation angle command of the servo motor, that is, by transmitting the pulse signals to the servo driver, the frequency and quantity of the pulse signals can be recorded by the pulse signal acquisition system, and the speed information V and displacement information S of the servo driver are correspondingly calculated; the servo driver comprises a servo motor shaft force loading device and / or a servo motor torsion device, the servo motor shaft force loading device is a loading device for realizing system displacement, speed or force by directly connecting the load on the motor shaft, the servo motor torsion device is a loading device for realizing system rotation angle, rotation speed or torque by directly connecting the load on the motor shaft, the loading device load acquisition sensor is used for obtaining real-time load information during the loading process, for example, a force sensor installed between the servo motor end and the loading head can obtain real-time load information F(t); the adaptive loading configuration module calculates and updates the parameter configuration information for loading according to the information acquired by the loading system parameter acquisition module by using the adaptive force source control method.

[0042] Embodiment 1

[0043] For a set of adaptive force control system, the target load 1 is 20N, the target load 2 is 40N, the target load 3 is 60N, the pre-set uniform loading phase load ratio is 1-γ, the adaptive factor α and the control coefficient β.

[0044] Loading starts, first into the linear loading phase: the loading device starts, records the instantaneous displacement S and the speed V, estimates the loaded object structure stiffness K, records the load F1 at the beginning, calculates the load change F D when reaching the target load 1 (i.e. F Δ = F D -F1, the linear loading phase speed V1 can be calculated:

[0045]

[0046] The speed is output to the loading device through the chip, and the system starts loading according to the speed. In this process, the loading system parameter acquisition module records various data in real time.

[0047] When the load reaches (1-λ)·F Δ , the deceleration loading phase is entered.

[0048] The remaining load is γF Δ . According to the uniform deceleration, the remaining total displacement is:

[0049]

[0050] K R is the instantaneous stiffness matrix at the moment of entering the deceleration loading phase;

[0051] From which the displacement deceleration of the uniform deceleration phase is calculated as:

[0052] V1 2 = 2aS

[0053] a = V1 2 / 2S = V1 2 / K2γF Δ

[0054] The adaptive factor needs to be added to prevent load overshoot, that is, by adaptive real-time correction of deceleration, replace V1 in it with V, so that the closer to the target displacement speed, the slower:

[0055]

[0056] S1 is the total displacement of this phase, and S t is the instantaneous displacement.

[0057] In this process, the calculated speed is output to the loading device in real time, the system updates the loading instruction in real time according to the obtained speed, and the loading module loads according to the instruction.

[0058] When the load reaches β·F D , the system enters the PID control stage, and the loading speed is: Figure 2

[0059]

[0060] Wherein, Ks is the instantaneous structural equivalent stiffness at the time of entering this stage, kp, ki, and kd are the equivalent control constants after dimensionless processing. By dimensionless processing the three parameters of the PID controller, proportion (kp), integration (ki), and differentiation (kd), it is not necessary to adjust them repeatedly according to different materials in the present application. Secondly, in each cycle, the instantaneous structural stiffness of the material to be loaded is estimated according to the load and displacement information fed back by the high-precision force sensor and displacement sensor (measuring element) matched with the loading platform, and is returned to the PID control equation as a control parameter, so that the self-optimization process of the PID control system can be realized.

[0061] The speed is output to the loading device through the chip, and the system starts loading according to the speed.

[0062] When the load is stable at the target load 1, i.e. F D = 20N, the loading is completed.

[0063] The next target load 2 loading process is started, and the above loading process is repeated. When the target load 2 is reached, the next target load 3 loading process is entered, and the loading strategy of the present application is repeated.

[0064] Example 2

[0065] The above method of the present application is used to perform a 500N five-section continuous loading and unloading test, which is performed three times in total, and the results are shown in Figure 3 It can be seen that the method has excellent performance in loading speed, loading accuracy, and loading stability, and has high consistency.

[0066] The above-described embodiments are only some of the preferred schemes of the present application, and are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.​

Claims

1. A fast high-precision high-stability self-adaptive force source control method, characterized in that, The adaptive loading process is divided into three stages, i.e., a linear constant-speed loading stage, a deceleration loading stage, and a PID stable control stage. The linear constant speed loading phase is freely set according to the working condition, the loading speed is as high as possible under the condition of permission, and the load proportion of the phase is freely set; when the constant speed loading phase is completed, the deceleration loading phase is entered, the instantaneous stiffness matrix when entering the deceleration phase, the distance from the target load state and the adaptive safety factor are combined, the deceleration state speed curve is real-timely regulated and controlled, so that the target load stable range is reached and the load overshoot phenomenon does not occur; when the load reaches the target load stable range, the PID stable control phase is entered, and the instantaneous stiffness matrix at this moment is used as an influencing factor and is applied to the PID control; the target load and the initial load , the difference value is obtained, and the proportion of the remaining load to be loaded after the linear constant speed loading phase is completed is set , and the loading speed of the linear constant speed loading phase is determined as: ， Wherein, K is the stiffness, and is determined as small as possible under the premise of meeting the working condition ; , and taking it as the speed of the loading in this stage. The cumulative load of the linear uniform loading stage is ; According to the load remaining after the uniform loading phase is completed , determining the speed to be adopted in the decelerating loading phase , specifically comprising: According to the residual load, the total displacement is calculated according to uniform deceleration as: ， Ktis the instantaneous stiffness matrix at the instant of entering the deceleration loading phase; If uniform deceleration is used, the corresponding deceleration needs to satisfy: ， That is, ， On the basis of uniform deceleration, an adaptive factor is added to prevent overshooting of the load, i.e. by adaptive real-time correction of the deceleration, the deceleration is replaced by V: ， wherein, is the total displacement amount of this phase, is the instantaneous displacement amount, and the loading is performed according to this speed strategy until the current loading load reaches wherein is a preset control coefficient, and then enters the PID stable control phase.

2. The fast high-precision high-stability self-adaptive force source control method according to claim 1, characterized in that, In the PID stable control stage, the target of controlling displacement is to minimize the error between the actual displacement and the expected displacement.

3. The fast high-precision high-stability self-adaptive force source control method according to claim 2, characterized in that, First, the kp, ki and kd parameters are dimensionless. In each cycle, the instantaneous structural stiffness of the loaded material needs to be estimated according to the load and displacement information fed back by the force sensor and displacement sensor in the loading platform, and then returned to the PID control equation as a control parameter to realize the self-optimization process of the PID control system. ， ， wherein, is the difference between the actual displacement of the system and the desired displacement, Ks is the instantaneous structural equivalent stiffness at the time of entering the PID control phase, kp, ki, kd are the dimensionless processed equivalent control constants, is the instantaneous load change amount, is the instantaneous displacement change amount.

4. A fast, high-precision, high-stability self-adaptive force source control system, characterized in that, It includes: a loading device module, a loading system parameter acquisition module, and an adaptive loading configuration module. The loading device module is used to execute the loading process of the target load or target displacement, including a pulse signal emitting device and a servo driver for axial force loading or torsion. The loading system parameter acquisition module is used to acquire the parameters generated by the system during the loading process, including a pulse signal acquisition system and a loading device load acquisition sensor. The pulse signal emitting device emits pulse signals to the servo driver, and the pulse signal acquisition system records the frequency and quantity of the pulse signals to calculate the speed information V and displacement information S of the servo driver. The adaptive loading configuration module calculates and updates the parameter configuration information for loading according to the information collected by the loading system parameter acquisition module using the adaptive force source control method of any one of claims 1-3.

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