Real-time compensation method and system for friction force and dynamic force in force control servo system

Abstract

The present invention relates to a real-time compensation method and system for friction and dynamic force in a force control servo system. The present invention includes obtaining an initial control voltage of a proportional valve; establishing a dynamic model of a pneumatic servo force control device; obtaining a dynamic force according to the displacement information and the dynamic model of a motion structure unit, and obtaining a compensation force for the dynamic force based on the dynamic force; establishing a relationship model between nonlinear friction and grinding contact force, cylinder output force and dynamic force; obtaining a compensation force for nonlinear friction based on the relationship model; obtaining a compensation voltage for a proportional pressure regulating valve, and obtaining a proportional valve control voltage based on the proportional pressure regulating valve compensation voltage and the initial control voltage of the proportional valve; obtaining a proportional valve voltage conversion air pressure coefficient of the proportional pressure regulating valve, and obtaining the output force after cylinder compensation based on the proportional pressure regulating valve control voltage, the proportional valve voltage conversion air pressure coefficient and the cylinder cross-sectional area of ​​a bidirectional cylinder. The present invention can compensate for nonlinear friction and dynamic forces in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of robot polishing, and in particular to a real-time compensation method and system for friction force and dynamic force in a force-controlled servo system. Background Art

[0002] In the robotic grinding system, in order to accurately control the output force during the grinding process, there are currently two implementation plans:

[0003] Solution one is to add a force sensor to the end of the robot. This solution realizes force-position coupled closed-loop control by installing a force sensor at the end of the robot, coordinating the robot position control with the contact force signal fed back by the sensor. Such as the solutions described in Chinese patents CN201910789065.1 and CN202410125295.9. However, this solution faces some problems: the position control accuracy of industrial robots can usually only reach the millimeter level, and such errors lead to inherent errors in force control accuracy. In addition, since the system relies on the feedback signal of the force sensor for closed-loop control, the bandwidth of the closed-loop control is low, so it is difficult to quickly respond to the needs of grinding force control under complex working conditions.

[0004] Solution 2 is to install an active force control device at the end of the robot. In order to overcome the defects in Solution 1, the grinding system adopts the design of Solution 2 more often, such as the solution described in Chinese patent CN202320473478.0. This solution installs an active force control device at the end of the robot, so that the device can directly output the set expected force according to the output force instruction of the upper system, thereby realizing the decoupling of the robot position control and the grinding contact force control. Since the force control device can respond quickly to changes in force, the system bandwidth is high and it is suitable for complex working conditions. However, although this solution controls the pressure of the proportional pressure regulating valve inside the force control device, it does not achieve full closed-loop control of the entire grinding system. In addition, due to the inevitable nonlinear friction force and dynamic force in the grinding process, the guide mechanism in the force control device still has errors in force control accuracy when the load is large or the robot position changes rapidly. Summary of the invention

[0005] To this end, the technical problem to be solved by the present invention is to overcome the influence of nonlinear friction and dynamic force on the force control accuracy in the existing robot grinding process, and provide a real-time compensation method and system for friction and dynamic force in a force control servo system. By performing dynamic modeling on the force control servo system, the nonlinear friction and dynamic force in the system are predicted, and the control accuracy is improved through real-time feedback compensation.

[0006] In order to solve the above technical problems, the present invention provides a real-time compensation method for friction force and dynamic force in a force control servo system, based on a pneumatic servo force control device and a controller unit, wherein the pneumatic servo force control device includes a proportional pressure regulating valve, an electromagnetic reversing valve, a bidirectional cylinder and a motion structure unit; wherein the controller unit can obtain sensor data in real time, and the sensor data includes displacement information of the motion structure unit, cylinder pressure information, posture information of the pneumatic servo device and grinding contact force information; the controller unit can obtain a compensation voltage of the proportional pressure regulating valve according to the sensor data, and realize motion control of the bidirectional cylinder through the electromagnetic reversing valve; the motion structure unit executes a motion driven by the bidirectional cylinder to realize force control grinding;

[0007] The real-time compensation method comprises:

[0008] Receiving an instruction of a desired grinding force, and obtaining an initial control voltage of the proportional valve according to a control coefficient of the proportional pressure regulating valve and the instruction of the desired grinding force;

[0009] Establishing a dynamic model of the pneumatic servo force control device;

[0010] Acquire displacement information of the motion structure unit, obtain a dynamic force according to the displacement information of the motion structure unit and the dynamic model, and obtain a compensation force of the dynamic force based on the dynamic force;

[0011] Obtaining grinding contact force information and cylinder output force, and establishing a relationship model between nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force;

[0012] Based on the relationship model, a compensation force of the nonlinear friction force is obtained;

[0013] Based on the compensation force of the dynamic force and the compensation force of the nonlinear friction force, a compensation voltage of the proportional pressure regulating valve is obtained, and based on the compensation voltage of the proportional pressure regulating valve and the initial control voltage of the proportional valve, a control voltage of the proportional valve is obtained;

[0014] The proportional valve voltage-to-pressure coefficient of the proportional pressure regulating valve and the cylinder cross-sectional area of ​​the bidirectional cylinder are obtained, and the output force after cylinder compensation is obtained based on the proportional pressure regulating valve control voltage, the proportional valve voltage-to-pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder.

[0015] In one embodiment of the present invention, the dynamic model of the pneumatic servo force control device is:

[0016] ;

[0017] in, It is the dynamic model of the pneumatic servo force control device;

[0018] is the modal mass of the pneumatic servo force control device;

[0019] is the system damping force coefficient;

[0020] is the system stiffness coefficient;

[0021] is a complex variable in the Laplace transform.

[0022] In one embodiment of the present invention, obtaining the dynamic force according to the displacement information of the motion structure unit and the dynamic model includes:

[0023] The dynamic force is obtained using the following formula:

[0024] ;

[0025] in, is the dynamic force;

[0026] is the displacement of the pneumatic servo device;

[0027] It is the dynamic model of the pneumatic servo force control device.

[0028] In one embodiment of the present invention, obtaining a compensation force for the dynamic force based on the dynamic force includes:

[0029] The compensation force of dynamic force is obtained by the following formula:

[0030] ;

[0031] in, is the compensation force for the dynamic force;

[0032] is the displacement of the pneumatic servo device;

[0033] It is the dynamic model of the pneumatic servo force control device.

[0034] In one embodiment of the present invention, the establishment of a relationship model between the nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force includes:

[0035] The relationship model is obtained using the following formula:

[0036] ;

[0037] in, To polish the contact force;

[0038] is the cylinder output force;

[0039] is the nonlinear friction force;

[0040] is the displacement of the pneumatic servo device;

[0041] It is the dynamic model of the pneumatic servo force control device.

[0042] In one embodiment of the present invention, obtaining the compensation force of the nonlinear friction force based on the relationship model includes:

[0043] The compensation force of nonlinear friction is obtained using the following formula:

[0044] ;

[0045] in, is the compensation force of nonlinear friction;

[0046] To polish the contact force;

[0047] is the cylinder output force;

[0048] is the displacement of the pneumatic servo device;

[0049] It is the dynamic model of the pneumatic servo force control device.

[0050] In one embodiment of the present invention, the output force after cylinder compensation is obtained based on the proportional pressure regulating valve control voltage, the proportional valve voltage conversion pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder, including:

[0051] The output force after cylinder compensation is obtained using the following formula:

[0052] ;

[0053] in, It is the output force after cylinder compensation;

[0054] It is the control voltage of the proportional valve;

[0055] It is the pressure conversion coefficient of the proportional valve voltage;

[0056] is the cylinder cross-sectional area of ​​the bidirectional cylinder.

[0057] In one embodiment of the present invention, the pneumatic servo force control device includes a sensor unit, and the controller unit includes an ARM module and an FPGA module;

[0058] The sensor unit includes a displacement sensor, a posture sensor, and a force sensor. The proportional pressure regulating valve, the displacement sensor, the posture sensor, and the force sensor are respectively connected to the controller unit through a sensor interface; the displacement sensor is used to obtain the displacement information of the motion structure unit, and the posture sensor is used to obtain the posture information of the pneumatic servo device;

[0059] The controller unit is capable of receiving the instruction of the desired grinding force, and the instruction of the desired grinding force is sent through the communication interface of the host computer;

[0060] The FPGA module receives the sensor data transmitted from the sensor unit, and the ARM module processes the sensor data and outputs a corresponding voltage to the proportional pressure regulating valve;

[0061] The proportional pressure regulating valve is connected to the gas circuit inlet, the proportional pressure regulating valve is connected to the electromagnetic reversing valve, and the proportional pressure regulating valve and the electromagnetic reversing valve are electrically connected to the controller unit respectively.

[0062] In one embodiment of the present invention, the electromagnetic reversing valve is a two-position five-way electromagnetic valve.

[0063] The present invention also provides a real-time compensation system for friction force and dynamic force in a force control servo system, comprising:

[0064] A proportional valve initial control voltage acquisition module, used for receiving an instruction of a desired grinding force, and obtaining an initial control voltage of the proportional valve according to a control coefficient of the proportional pressure regulating valve and the instruction of the desired grinding force;

[0065] Dynamic model building module, used to establish the dynamic model of the pneumatic servo force control device;

[0066] A dynamic force compensation force acquisition module, used to acquire displacement information of the motion structure unit, obtain dynamic force according to the displacement information of the motion structure unit and the dynamic model, and obtain compensation force of the dynamic force based on the dynamic force;

[0067] A relationship model building module, used to obtain grinding contact force information and cylinder output force, and to build a relationship model between nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force;

[0068] A nonlinear friction compensation force acquisition module, used to obtain the nonlinear friction compensation force based on the relationship model;

[0069] A proportional valve control voltage acquisition module, used to obtain a proportional pressure regulating valve compensation voltage based on the dynamic force compensation force and the nonlinear friction force compensation force, and to obtain a proportional valve control voltage based on the proportional pressure regulating valve compensation voltage and the proportional valve initial control voltage;

[0070] The cylinder compensation output force acquisition module is used to obtain the proportional valve voltage conversion air pressure coefficient of the proportional pressure regulating valve and the cylinder cross-sectional area of ​​the bidirectional cylinder, and obtains the cylinder compensation output force based on the proportional pressure regulating valve control voltage, the proportional valve voltage conversion air pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder.

[0071] The above technical solution of the present invention has the following advantages compared with the prior art:

[0072] The real-time compensation method and system for friction and dynamic force in a force-controlled servo system of the present invention establishes a relationship model between nonlinear friction and grinding contact force, cylinder output force and dynamic force by performing dynamic modeling on the force-controlled servo system, and performs real-time compensation for nonlinear friction and dynamic force based on the model. This effectively overcomes the accuracy problem caused by friction and dynamic force in traditional servo systems, and significantly improves the force control accuracy of the system under complex working conditions.

[0073] The invention ensures that the force control system can be adjusted in real time and maintain high-precision force output through multi-signal feedback of force sensors, displacement sensors, and attitude sensors. In particular, closed-loop control improves the force output stability of the system under dynamically changing working conditions.

[0074] The ZYNQ chip of the present invention integrates a high-performance ARM processor and an FPGA. The FPGA module is used to collect sensor data at high speed with a collection period of 200 microseconds, and the ARM module processes the data and calculates a suitable voltage signal. Compared with the traditional PLC control method, the present invention greatly improves the data collection speed of the system and the execution efficiency of the control algorithm, thereby enhancing the control accuracy and real-time performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0076] Figure 1 It is a flow chart of the real-time compensation method of friction force and dynamic force in the force control servo system of the present invention.

[0077] Figure 2 It is a principle diagram of the real-time compensation system for friction force and dynamic force in the force control servo system of the present invention.

[0078] Figure 3It is a structural diagram of the real-time compensation system for friction force and dynamic force in the force control servo system of the present invention. DETAILED DESCRIPTION

[0079] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0080] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0081] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0082] Example 1

[0083] This embodiment provides a real-time compensation method for friction and dynamic force in a force control servo system, based on a pneumatic servo force control device and a controller unit, referring to Figure 3 As shown, the pneumatic servo force control device includes a proportional pressure regulating valve, an electromagnetic reversing valve, a bidirectional cylinder and a motion structure unit; wherein the controller unit can obtain sensor data in real time, and the sensor data includes displacement information of the motion structure unit, cylinder pressure information, posture information of the pneumatic servo device and grinding contact force information. The controller unit can obtain the compensation voltage of the proportional pressure regulating valve according to the sensor data, and realize the motion control of the bidirectional cylinder through the electromagnetic reversing valve. The motion structure unit executes the motion driven by the bidirectional cylinder to realize force-controlled grinding.

[0084] It can be understood that the motion structure unit is an actuator driven by a bidirectional cylinder, which receives force from the bidirectional cylinder to perform corresponding physical displacement or posture adjustment, thereby completing tasks such as grinding, such as grinding tools, the end part of the robotic arm, etc.

[0085] Through the feedback of the posture information of the pneumatic servo device, the grinding contact force information and the displacement information of the motion structure unit, the system can better compensate for the friction and dynamic force in real time and improve the control stability of the system.

[0086] Reference Figure 1 , Figure 2 As shown, the real-time compensation method includes:

[0087] S1, receiving an instruction of a desired grinding force, and obtaining an initial control voltage of the proportional valve according to a control coefficient of the proportional pressure regulating valve and the instruction of the desired grinding force;

[0088] S2. Establishing a dynamic model of the pneumatic servo force control device;

[0089] S3, obtaining displacement information of the motion structure unit, obtaining a dynamic force according to the displacement information of the motion structure unit and the dynamic model, and obtaining a compensation force of the dynamic force based on the dynamic force;

[0090] S4, obtaining grinding contact force information and cylinder output force, and establishing a relationship model between nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force;

[0091] S5. Obtaining a compensation force for the nonlinear friction force based on the relationship model;

[0092] S6. Obtaining a proportional pressure regulating valve compensation voltage based on the dynamic force compensation force and the nonlinear friction force compensation force, and obtaining a proportional valve control voltage based on the proportional pressure regulating valve compensation voltage and the proportional valve initial control voltage;

[0093] S7. Obtain the proportional valve voltage-to-pressure coefficient of the proportional pressure regulating valve and the cylinder cross-sectional area of ​​the bidirectional cylinder, and obtain the output force after cylinder compensation based on the proportional pressure regulating valve control voltage, the proportional valve voltage-to-pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder.

[0094] It should be noted that the dynamic model of the pneumatic servo force control device mainly includes the cylinder output force, nonlinear friction force, inertia force, damping force and system stiffness force. Inertia force, damping force and system stiffness force are uniformly defined as the dynamic force of the system.

[0095] Specifically, the initial control voltage of the proportional valve is: r*Kv,

[0096] in, r Grind force for expectation; Kv is the control coefficient of the proportional pressure regulating valve.

[0097] Specifically, the dynamic model of the pneumatic servo force control device is:

[0098] ;

[0099] in, It is the dynamic model of the pneumatic servo force control device;

[0100] is the modal mass of the pneumatic servo force control device;

[0101] is the system damping force coefficient;

[0102] is the system stiffness coefficient;

[0103] is a complex variable in the Laplace transform.

[0104] Specifically, obtaining the dynamic force according to the displacement information of the motion structure unit and the dynamic model includes:

[0105] The dynamic force is obtained using the following formula:

[0106] ;

[0107] in, is the dynamic force;

[0108] is the displacement of the pneumatic servo device;

[0109] It is the dynamic model of the pneumatic servo force control device.

[0110] Specifically, obtaining the compensation force of the dynamic force based on the dynamic force includes:

[0111] The compensation force of dynamic force is obtained by the following formula:

[0112] ;

[0113] in, is the compensation force for the dynamic force;

[0114] is the displacement of the pneumatic servo device;

[0115] It is the dynamic model of the pneumatic servo force control device.

[0116] Specifically, the establishing of the relationship model between the nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force includes:

[0117] The relationship model is obtained using the following formula:

[0118] ;

[0119] in, To polish the contact force;

[0120] is the cylinder output force;

[0121] is the nonlinear friction force;

[0122] is the displacement of the pneumatic servo device;

[0123] It is the dynamic model of the pneumatic servo force control device.

[0124] Specifically, obtaining the compensation force of the nonlinear friction force based on the relationship model includes:

[0125] The compensation force of nonlinear friction is obtained using the following formula:

[0126] ;

[0127] in, is the compensation force of nonlinear friction;

[0128] To polish the contact force;

[0129] is the cylinder output force;

[0130] is the displacement of the pneumatic servo device;

[0131] It is the dynamic model of the pneumatic servo force control device.

[0132] Specifically, the proportional pressure regulating valve compensation voltage is obtained as [ .

[0133] Proportional valve control voltage =[ .

[0134] Specifically, the output force after cylinder compensation is obtained based on the proportional pressure regulating valve control voltage, the proportional valve voltage conversion pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder, including:

[0135] The output force after cylinder compensation is obtained using the following formula:

[0136] ;

[0137] in, It is the output force after cylinder compensation;

[0138] It is the control voltage of the proportional valve;

[0139] It is the pressure conversion coefficient of the proportional valve voltage;

[0140] is the cylinder cross-sectional area of ​​the bidirectional cylinder.

[0141] In this embodiment, the controller unit adopts a ZYNQ chip. The ZYNQ chip is a device that integrates a high-performance ARM Cortex A9 core and a programmable logic FPGA, including an FPGA module and an ARM module. The FPGA module is used to collect sensor signals and control signal outputs, and the ARM module is used to perform controller algorithm module calculations. Compared with traditional PLC control methods, the sensor signal collection speed and the controller algorithm operation cycle are improved, thereby significantly improving the control accuracy.

[0142] The pneumatic servo force control device comprises a sensor unit, which comprises a displacement sensor, a posture sensor, and a force sensor. The proportional pressure regulating valve, the displacement sensor, the posture sensor, and the force sensor are respectively connected to the controller unit through a sensor interface; the displacement sensor is used to obtain displacement information of the motion structure unit, and the posture sensor is used to obtain posture information of the pneumatic servo device; the proportional pressure regulating valve detects cylinder air pressure information in real time, and controls the force output by the cylinder by adjusting the air pressure inside the cylinder;

[0143] The controller unit is capable of receiving the instruction of the desired grinding force through its communication interface, and the instruction of the desired grinding force is sent through the communication interface of the host computer;

[0144] The FPGA module receives sensor data transmitted from the sensor unit through the sensor interface, and the acquisition cycle is 200us; the ARM module processes the sensor data, calculates through the internal algorithm module, and outputs the corresponding voltage to the proportional pressure regulating valve;

[0145] The gas circuit input interface of the proportional pressure regulating valve is directly connected to the air inlet, the electrical input interface is connected to the voltage output port of the ZYNQ controller unit, the gas circuit output interface of the proportional pressure regulating valve is connected to the electromagnetic reversing valve, and the air pressure feedback interface of the proportional pressure regulating valve is connected to the sensor interface.

[0146] The electromagnetic reversing valve is a two-position five-way electromagnetic valve, which is respectively connected to two gas outlets, and the two gas outlets are respectively connected to the gas input interface of the bidirectional cylinder, and the bidirectional cylinder is connected to the motion structure unit.

[0147] The motion structure unit is connected to a displacement sensor, and the displacement sensor detects position information of the motion structure unit in real time.

[0148] The pneumatic servo device also includes a posture sensor for detecting the posture information of the pneumatic servo device in real time.

[0149] The output signal of the force sensor is connected to the input interface of ZYNQ through the sensor interface to detect the current contact force in real time.

[0150] It is understandable that when the pneumatic servo force control device is actually working, the FPGA module in the controller unit collects signals from the force sensor, proportional pressure regulating valve, displacement sensor and posture sensor every 200 microseconds, and writes these signal data into the memory of the ZYNQ controller unit, triggering a software interrupt signal at the same time. The ARM module responds to the interrupt signal, reads the sensor data in the memory, and uses it as the input parameter of the control algorithm module. The control algorithm module calculates based on these data, generates the corresponding voltage output value, and transmits the value to the FPGA module. After receiving the voltage output, the FPGA module sends the corresponding voltage signal to the electrical input interface of the proportional pressure regulating valve to ensure that the output of the pneumatic servo device meets the expected force set by the host computer system.

[0151] The host computer sends the desired force command required for grinding to the controller unit through the communication interface. The controller unit compensates for the friction and dynamic forces through the control algorithm module based on the data collected by the sensor, calculates and generates the corresponding voltage signal and transmits it to the proportional pressure regulating valve. The proportional pressure regulating valve adjusts the air pressure of the gas circuit according to the voltage signal and outputs the gas to the electromagnetic reversing valve. The electromagnetic reversing valve adjusts the flow direction of the gas according to the control signal sent by the controller unit, drives the bidirectional cylinder to move, and thus changes the position of the pneumatic servo device.

[0152] The proportional pressure regulating valve detects the cylinder pressure in real time, the displacement sensor is used to detect the position information of the pneumatic servo device, the attitude sensor detects the attitude change of the motion structure unit, and the force sensor detects the grinding contact force in real time. After the feedback signals of these sensors are collected, they are processed by the ZYNQ controller unit to form a closed-loop control to ensure that the system can accurately output the required expected force.

[0153] By establishing a mathematical model of the pneumatic servo device and designing corresponding friction and dynamic force compensation algorithms, the problem of the inability to accurately measure friction is solved, making the entire system form a complete closed loop, improving the system's response bandwidth, and improving the system's force control accuracy.

[0154] Example 2

[0155] Based on the same inventive concept, this embodiment provides a real-time compensation system for friction and dynamic force in a force-controlled servo system. The principle of solving the problem is similar to the real-time compensation method for friction and dynamic force in the force-controlled servo system, and the repeated parts are not repeated here.

[0156] This embodiment provides a real-time compensation system for friction and dynamic force in a force control servo system, comprising:

[0157] A proportional valve initial control voltage acquisition module, used for receiving an instruction of a desired grinding force, and obtaining an initial control voltage of the proportional valve according to a control coefficient of the proportional pressure regulating valve and the instruction of the desired grinding force;

[0158] Dynamic model building module, used to establish the dynamic model of the pneumatic servo force control device;

[0159] A dynamic force compensation force acquisition module, used to acquire displacement information of the motion structure unit, obtain dynamic force according to the displacement information of the motion structure unit and the dynamic model, and obtain compensation force of the dynamic force based on the dynamic force;

[0160] A relationship model building module, used to obtain grinding contact force information and cylinder output force, and to build a relationship model between nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force;

[0161] A nonlinear friction compensation force acquisition module, used to obtain the nonlinear friction compensation force based on the relationship model;

[0162] A proportional valve control voltage acquisition module, used to obtain a proportional pressure regulating valve compensation voltage based on the dynamic force compensation force and the nonlinear friction force compensation force, and to obtain a proportional valve control voltage based on the proportional pressure regulating valve compensation voltage and the proportional valve initial control voltage;

[0163] The cylinder compensation output force acquisition module is used to obtain the proportional valve voltage conversion air pressure coefficient of the proportional pressure regulating valve and the cylinder cross-sectional area of ​​the bidirectional cylinder, and obtains the cylinder compensation output force based on the proportional pressure regulating valve control voltage, the proportional valve voltage conversion air pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder.

[0164] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0165] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0166] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0167] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0168] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A real-time compensation method for friction and dynamic force in a force control servo system, characterized in that: Based on a pneumatic servo force control device and a controller unit, the pneumatic servo force control device includes a proportional pressure regulating valve, an electromagnetic reversing valve, a bidirectional cylinder and a motion structure unit; wherein the controller unit can obtain sensor data in real time, the sensor data includes displacement information of the motion structure unit, cylinder pressure information, posture information of the pneumatic servo device and grinding contact force information, the controller unit can obtain a compensation voltage of the proportional pressure regulating valve according to the sensor data, and realize motion control of the bidirectional cylinder through the electromagnetic reversing valve, the motion structure unit executes the motion driven by the bidirectional cylinder to realize force-controlled grinding; The real-time compensation method comprises: Receiving an instruction of a desired grinding force, and obtaining an initial control voltage of the proportional valve according to a control coefficient of the proportional pressure regulating valve and the instruction of the desired grinding force; Establishing a dynamic model of the pneumatic servo force control device; Acquire displacement information of the motion structure unit, obtain a dynamic force according to the displacement information of the motion structure unit and the dynamic model, and obtain a compensation force of the dynamic force based on the dynamic force; Obtaining grinding contact force information and cylinder output force, and establishing a relationship model between nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force; Based on the relationship model, a compensation force of the nonlinear friction force is obtained; Based on the compensation force of the dynamic force and the compensation force of the nonlinear friction force, a compensation voltage of the proportional pressure regulating valve is obtained, and based on the compensation voltage of the proportional pressure regulating valve and the initial control voltage of the proportional valve, a control voltage of the proportional valve is obtained; The proportional valve voltage-to-pressure coefficient of the proportional pressure regulating valve and the cylinder cross-sectional area of ​​the bidirectional cylinder are obtained, and the output force after cylinder compensation is obtained based on the proportional pressure regulating valve control voltage, the proportional valve voltage-to-pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder.

2. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The dynamic model of the pneumatic servo force control device is: ； in, It is the dynamic model of the pneumatic servo force control device; is the modal mass of the pneumatic servo force control device; is the system damping force coefficient; is the system stiffness coefficient; is a complex variable in the Laplace transform.

3. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The obtaining of the dynamic force according to the displacement information of the motion structure unit and the dynamic model comprises: The dynamic force is obtained using the following formula: ； in, is the dynamic force; is the displacement of the pneumatic servo device; It is the dynamic model of the pneumatic servo force control device.

4. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The step of obtaining a compensation force for the dynamic force based on the dynamic force comprises: The compensation force of dynamic force is obtained by the following formula: ； in, is the compensation force for the dynamic force; is the displacement of the pneumatic servo device; It is the dynamic model of the pneumatic servo force control device.

5. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The establishing of the relationship model between the nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force comprises: The relationship model is obtained using the following formula: ； in, To polish the contact force; is the cylinder output force; is the nonlinear friction force; is the displacement of the pneumatic servo device; It is the dynamic model of the pneumatic servo force control device.

6. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The obtaining of the compensation force of the nonlinear friction force based on the relationship model comprises: The compensation force of nonlinear friction is obtained using the following formula: ； in, is the compensation force of nonlinear friction; To polish the contact force; is the cylinder output force; is the displacement of the pneumatic servo device; It is the dynamic model of the pneumatic servo force control device.

7. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The method of obtaining the output force after cylinder compensation based on the proportional pressure regulating valve control voltage, the proportional valve voltage conversion pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder comprises: The output force after cylinder compensation is obtained using the following formula: ； in, It is the output force after cylinder compensation; It is the control voltage of the proportional valve; It is the pressure conversion coefficient of the proportional valve voltage; is the cylinder cross-sectional area of ​​the bidirectional cylinder.

8. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The pneumatic servo force control device includes a sensor unit, and the controller unit includes an ARM module and an FPGA module; The sensor unit includes a displacement sensor, a posture sensor, and a force sensor. The proportional pressure regulating valve, the displacement sensor, the posture sensor, and the force sensor are respectively connected to the controller unit through a sensor interface; the displacement sensor is used to obtain the displacement information of the motion structure unit, and the posture sensor is used to obtain the posture information of the pneumatic servo device; The controller unit is capable of receiving the instruction of the desired grinding force, and the instruction of the desired grinding force is sent through the communication interface of the host computer; The FPGA module receives the sensor data transmitted from the sensor unit, and the ARM module processes the sensor data and outputs a corresponding voltage to the proportional pressure regulating valve; The proportional pressure regulating valve is connected to the gas circuit inlet, the proportional pressure regulating valve is connected to the electromagnetic reversing valve, and the proportional pressure regulating valve and the electromagnetic reversing valve are electrically connected to the controller unit respectively.

9. The real-time compensation method for friction force and dynamic force in a force control servo system according to claim 1, characterized in that: The electromagnetic reversing valve adopts a two-position five-way electromagnetic valve.

10. A real-time compensation system for friction and dynamic force in a force control servo system, characterized in that: include: A proportional valve initial control voltage acquisition module, used for receiving an instruction of a desired grinding force, and obtaining an initial control voltage of the proportional valve according to a control coefficient of the proportional pressure regulating valve and the instruction of the desired grinding force; Dynamic model building module, used to establish the dynamic model of the pneumatic servo force control device; A dynamic force compensation force acquisition module, used to acquire displacement information of the motion structure unit, obtain dynamic force according to the displacement information of the motion structure unit and the dynamic model, and obtain compensation force of the dynamic force based on the dynamic force; A relationship model building module, used to obtain grinding contact force information and cylinder output force, and to build a relationship model between nonlinear friction force and the grinding contact force, the cylinder output force and the dynamic force; A nonlinear friction compensation force acquisition module, used to obtain the nonlinear friction compensation force based on the relationship model; A proportional valve control voltage acquisition module, used to obtain a proportional pressure regulating valve compensation voltage based on the dynamic force compensation force and the nonlinear friction force compensation force, and to obtain a proportional valve control voltage based on the proportional pressure regulating valve compensation voltage and the proportional valve initial control voltage; The cylinder compensation output force acquisition module is used to obtain the proportional valve voltage conversion air pressure coefficient of the proportional pressure regulating valve and the cylinder cross-sectional area of ​​the bidirectional cylinder, and obtains the cylinder compensation output force based on the proportional pressure regulating valve control voltage, the proportional valve voltage conversion air pressure coefficient and the cylinder cross-sectional area of ​​the bidirectional cylinder.

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