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

Abstract

The invention discloses a rapid high-precision high-stability self-adaptive force source control method and system, and the method comprises the steps: dividing a loading process into three sections: linear constant-speed loading, deceleration loading and stable control loading, and freely setting the proportion and speed of the loading stage in the linear constant-speed loading stage, so as to achieve the purpose that a load rapidly and efficiently reaches the vicinity of a target load, and achieve the purpose of stable control. In the deceleration loading stage, the instantaneous structural rigidity, the target load distance and the self-adaptive safety factor are combined, so that the load quickly and stably enters a target load stability range, and in the PID stability control stage, an instantaneous rigidity matrix is used as an influence factor to act on PID control; by adopting the method, quick, accurate and stable loading of the load can be realized.

Description

Technical Field

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

[0002] Servo motor control systems are widely used in industrial automation, robotics, aerospace and other fields to achieve precise position control, speed control or force control. These systems usually include components such as sensors, actuators, controllers and feedback loops, and achieve precise control of actuators such as motors by continuously adjusting the output of the controller. For some specific applications, such as precision machining or precise positioning, higher control accuracy and stability are required, and traditional control methods may not be able to meet the requirements; and the servo motor system itself may have nonlinearity and time-varying properties, 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 motors to a certain extent, but there are still some shortcomings, such as: PID control is simple and easy to implement, but the control ability for complex systems and nonlinear systems is limited, and often requires parameter adjustment to obtain better performance; fuzzy control can handle nonlinear systems, but the design of fuzzy rules and the determination of fuzzy sets are relatively subjective and easily affected by environmental changes; 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 characteristics make it difficult to explain and debug.

[0004] In summary, the existing technology often finds it difficult to achieve fast, high-precision, and high-stability control of the servo system in mechanical loading. Summary of the invention

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

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

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

[0008] The linear uniform loading stage is to freely set the loading speed according to the working conditions, increase the loading speed as much as possible when conditions permit, and freely set the proportion of this stage; after completing the uniform loading stage, enter the deceleration loading stage, and by combining the instantaneous stiffness matrix when entering the deceleration stage, the distance target load state and the adaptive safety factor, the deceleration state speed curve is controlled in real time to achieve the target load stability range without load overshoot; when the load reaches the target load stability range, enter the PID stable control stage, and use the instantaneous stiffness matrix at this moment as an influencing factor to act on the PID control.

[0009] In the above technical solution, further, the target load F is obtained D and the initial load F0, take the difference F Δ , and set the proportion γ of the remaining load to be loaded after the linear uniform loading stage is completed, and determine the loading speed of the linear uniform loading stage as:

[0010]

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

[0012] Furthermore, according to the residual load γF after completing the uniform loading stage Δ , determine the speed V1 required in the deceleration loading stage, including:

[0013] According to the residual load and uniform deceleration, the total displacement is calculated as:

[0014]

[0015] K R is the instantaneous stiffness matrix when entering the deceleration loading stage;

[0016] From this calculation, we can see 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 modified in real time through adaptive adaptation, and V1 is replaced by V:

[0021]

[0022] Among them, S1 is the total displacement in this stage, S t is the instantaneous displacement, and loading is performed according to the speed strategy until the current loading load reaches β·F D , where β is the preset control coefficient, then it enters the PID stable control stage.

[0023] Furthermore, the PID stable control stage is entered. The goal of controlling the displacement in this stage is to minimize the difference between the actual displacement of the system and the expected displacement, that is, the error.

[0024] Furthermore, the kp, ki, and kd parameters are first dimensionally processed. In each cycle, the instantaneous structural stiffness of the loaded material needs to be estimated based on the load and displacement information fed back by the force sensor and displacement sensor in the loading platform, and this is used as the control parameter to return to the PID control equation. The above process is repeated to realize the self-optimization process of the PID control system:

[0025]

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

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

[0028] The loading device module is used to perform a loading process for a target load or a target displacement, and includes a pulse signal transmitting 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 includes a pulse signal acquisition system and a loading device load acquisition sensor; the pulse signal transmitting device transmits a pulse signal to the servo driver, and the pulse signal acquisition system records the frequency and quantity of the pulse signal, and calculates the speed information V and displacement information S of the servo driver accordingly; the loading device load acquisition sensor is used to obtain real-time load information during the loading process;

[0030] The adaptive loading configuration module calculates and updates the parameter configuration information for loading based on the information collected by the loading system parameter collection module using the adaptive force source control method as described in any one of the above items.

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

[0032] The control method of the present invention divides the loading process into sections: the first section is linear uniform speed loading, the second section is deceleration loading, and the third section is PID stable control loading. It can achieve fast, accurate and stable loading of the load. Specifically:

[0033] In the linear uniform loading stage, since the proportion and speed of the loading stage can be freely set, the load can reach the target load quickly and efficiently; and this process can be freely controlled according to the loading speed and the proportion parameters of the straight line stage length.

[0034] During the deceleration loading stage, since the loading process in this stage refers to the instantaneous structural stiffness, target load distance and adaptive safety factor, the load can quickly and stably enter the target load stability range, and the slope of the curve tends to be horizontal at this time, and there will be no load overshoot; and this process can be controlled based on the adaptive safety factor.

[0035] When entering the PID stable control stage at the end, compared with the PID stable control algorithm with full intervention or the PID stable control algorithm with intervention at the end of loading, the loading process has become much smoother when entering the target load stability range, so there is basically no load oscillation and load stabilization can be achieved very quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the adaptive loading process in the method of the present invention;

[0037] Figure 2 It is the principle diagram of PID control system in the method of the present invention;

[0038] Figure 3 Schematic diagram of the uniaxial continuous loading and unloading effect. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0040] The adaptive force source control method of the present invention divides the adaptive loading process into three stages: linear uniform speed loading stage, deceleration loading stage and PID stable control stage. Figure 1As shown in the figure, the loading speed can be freely set according to the working conditions in the linear uniform loading stage, and the loading speed can be increased as much as possible when conditions permit, and the proportion of this stage can be freely set, which can improve the loading efficiency; the deceleration loading stage, that is, when the uniform loading stage is completed, enters the deceleration stage, and the speed curve of the deceleration state depends on the instantaneous stiffness matrix, the distance target load state and the adaptive safety factor when entering the deceleration stage, that is, the deceleration curve is adjusted in real time, which can achieve efficient and stable reaching of the target load stability range, and there will be no load overshoot phenomenon; when the load reaches the target load stability range, that is, the PID stable control stage, the instantaneous stiffness matrix at this moment is used as an influencing factor to act on the PID control algorithm. At this time, the PID control algorithm has targeted control parameters and begins to control the loading process to be stable. Due to the stable transition of the curve brought by the previous deceleration stage, the PID control algorithm can achieve load stability control in a very short time, basically no load oscillation, and can quickly enter the next loading stage.

[0041] The method can realize the corresponding functions based on the following system, which includes: a loading device module, a loading system parameter acquisition module, and an adaptive loading configuration module; wherein: the loading device module is used to execute the loading process of the target load or target displacement, and includes a pulse signal transmitting device, and a servo driver for axial force loading or torsion; the loading system parameter acquisition module is used to collect the parameters generated by the system during the loading process, and includes a pulse signal acquisition system and a loading device load acquisition sensor; the pulse signal transmitting device is a numerical control device that transmits a pulse command signal to the servo driver, and the frequency and number of the pulse signal represent the speed and displacement or the speed and angle command of the servo motor, that is, by transmitting a pulse signal to the servo driver, the frequency and number of the pulse signal can be recorded by the pulse signal acquisition system, and the corresponding calculation servo The servo drive 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 a 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 a load on the motor shaft. The load acquisition sensor of the loading device is used to obtain real-time load information during the loading process. For example, a force sensor installed between the end of the servo motor and the loading head can obtain real-time load information F(t) during the loading process. 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 described in the present invention.

[0042] Example 1

[0043] For an adaptive force source control system, it is required to continuously apply target load 1 of 20N, target load 2 of 40N, and target load 3 of 60N. The load proportion of the uniform loading stage is pre-set as 1-γ, the adaptive factor α, and the control coefficient β.

[0044] Loading begins, and the linear loading phase begins: the loading device is started, the instantaneous displacement S and velocity V are recorded, the structural stiffness K of the loaded object is estimated, the initial load F1 is recorded, and the target load 1 (i.e. F1) is calculated. D ) when the load change F Δ =F D -F1, can calculate the linear loading stage speed V1:

[0045]

[0046] This speed is output to the loading device through the chip, and the system starts loading at this speed. During this process, various data are recorded in real time in the loading system parameter acquisition module.

[0047] When the load reaches (1-λ)·F Δ , it enters the deceleration loading stage.

[0048] The residual load is γF Δ Considering uniform deceleration, the remaining total displacement is:

[0049]

[0050] K R is the instantaneous stiffness matrix when entering the deceleration loading stage;

[0051] The displacement deceleration in the uniform deceleration stage is calculated to satisfy:

[0052] V1 2 =2aS

[0053] a=V1 2 / 2S=V1 2 / K2γF Δ

[0054] An adaptive factor needs to be added to prevent load overshoot, that is, the deceleration is modified in real time by adaptively replacing V1 with V, so that the closer to the target displacement, the slower the speed:

[0055]

[0056] S1 is the total displacement in this stage, S t is the instantaneous displacement.

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

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

[0059]

[0060] Among them, Ks is the instantaneous structural equivalent stiffness at the moment of entering this stage, and kp, ki, and kd are equivalent control constants that have been dimensionally processed. By dimensionally processing the three parameters of the PID controller, namely, the proportion (kp), integral (ki), and differential (kd), it is not necessary to adjust them repeatedly according to different materials in the present invention; secondly, in each cycle, the instantaneous structural stiffness of the loaded material is estimated based on the load and displacement information fed back by the high-precision force sensor and displacement sensor (measuring element) of the loading platform, and this is used as the control parameter to return to the PID control equation, thereby realizing the self-optimization process of the PID control system.

[0061] This speed is output to the loading device through the chip, and the system starts loading at this speed.

[0062] When the load stabilizes at the target load 1, F D When =20N, loading ends.

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

[0064] Example 2

[0065] The above method of the present invention was used to carry out a 500N five-stage continuous loading and unloading test for a total of three times. The results are as follows Figure 3 As shown, it can be seen that this method has excellent performance in loading speed, loading accuracy, loading stability, and has high consistency.

[0066] The above-described embodiments are only some of the preferred solutions of the present invention, but they are not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A fast, high-precision, and high-stability adaptive force source control method, characterized in that: The adaptive loading process is divided into three stages: linear uniform speed loading stage, deceleration loading stage, and PID stable control stage; among which: The linear uniform loading stage is to freely set the loading speed according to the working conditions, increase the loading speed as much as possible when conditions permit, and freely set the proportion of this stage; after completing the uniform loading stage, enter the deceleration loading stage, and by combining the instantaneous stiffness matrix when entering the deceleration stage, the distance target load state and the adaptive safety factor, the deceleration state speed curve is controlled in real time to achieve the target load stability range without load overshoot; when the load reaches the target load stability range, enter the PID stable control stage, and use the instantaneous stiffness matrix at this moment as an influencing factor to act on the PID control.

2. The fast, high-precision, and high-stability adaptive force source control method according to claim 1 is characterized in that: Get the target load F D and the initial load F0, take the difference F Δ , and set the proportion γ of the remaining load to be loaded after the linear uniform loading stage is completed, and determine the loading speed of the linear uniform loading stage as: Where K is the stiffness. V1 is determined by making T1 as small as possible under the premise of satisfying the working conditions, and it is used as the speed adopted for loading in this stage. The cumulative load in this linear uniform loading stage is (1-γ)F Δ .

3. The fast, high-precision, and high-stability adaptive force source control method according to claim 2 is characterized in that: According to the residual load γF after completing the uniform loading stage Δ , determine the speed V1 required in the deceleration loading stage, including: According to the residual load and uniform deceleration, the total displacement is calculated as: K R is the instantaneous stiffness matrix when entering the deceleration loading stage; From this calculation, we can see that if uniform deceleration is used, the corresponding deceleration must satisfy: V1 2 =2aS That is: a=V1 2 / 2S=V1 2 K / 2γF Δ An adaptive factor is added to the uniform deceleration to prevent load overshoot, that is, the deceleration is modified in real time through adaptive adaptation, and V1 is replaced by V: Among them, S1 is the total displacement in this stage, S t is the instantaneous displacement, and loading is performed according to the speed strategy until the current loading load reaches β·F D , where β is the preset control coefficient, then it enters the PID stable control stage.

4. The fast, high-precision, and high-stability adaptive force source control method according to claim 1 is characterized in that: Entering the PID stable control stage, the goal of controlling the displacement in this stage is to minimize the difference between the actual displacement of the system and the expected displacement, that is, the error.

5. The fast, high-precision, and high-stability adaptive force source control method according to claim 4 is 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 based on the load and displacement information fed back by the force sensor and displacement sensor in the loading platform, and this is used as the control parameter to return to the PID control equation. The above process is repeated to realize the self-optimization process of the PID control system: Among them, error(t) is the difference between the actual displacement and the expected displacement of the system, Ks is the instantaneous structural equivalent stiffness when entering the PID control stage, kp, ki, kd are dimensionless equivalent control constants, ΔF is the instantaneous load change, and Δl is the instantaneous displacement change.

6. A fast, high-precision, and high-stability adaptive force source control system, characterized in that: include: Loading device module, loading system parameter acquisition module, adaptive loading configuration module; The loading device module is used to perform a loading process for a target load or a target displacement, and includes a pulse signal transmitting 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, and includes a pulse signal acquisition system and a loading device load acquisition sensor; the pulse signal transmitting device transmits a pulse signal to the servo driver, and the pulse signal acquisition system records the frequency and quantity of the pulse signal, and calculates the speed information V and displacement information S of the servo driver accordingly; the loading device load acquisition sensor is used to obtain real-time load information during the loading process; The adaptive loading configuration module calculates and updates the parameter configuration information for loading based on the information collected by the loading system parameter collection module using the adaptive force source control method according to any one of claims 1 to 5.

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