Pre-defined time preset performance robust force control method for pneumatic grinding equipment

Abstract

The invention discloses a predefined time preset performance robust force control method for pneumatic grinding equipment, which comprises the following steps of: determining an expected force signal based on an incidence relation between a first acting force and a second acting force; based on the expected force signal as input of a rate-dependent inverse hysteresis model, obtaining expected air pressure output by the rate-dependent inverse hysteresis model; on the basis of the expected air pressure, a practical predefined time disturbance observer is combined, and a practical predefined time controller is constructed; and controlling the opening degree of the proportional pressure regulating valve by utilizing a practical predefined time controller, so that the first acting force meets the expected value of the first acting force. According to the method, when the frequency of the expected force signal changes, satisfactory force control precision can still be achieved, external disturbance can be accurately observed within the artificially specified time, the robustness of force control is improved, the air pressure tracking error can be converged to the specified progress within the artificially specified time, and the accuracy of force control is improved. And the control precision and the response speed of force control are improved.

Description

Technical Field

[0001] The present application relates to the technical field of force control of grinding robots, and in particular to a robust force control method with predefined time and preset performance for pneumatic grinding equipment. Background Art

[0002] Grinding and polishing are an indispensable part of the manufacturing industry. With the development and progress of science and technology, the demand for high-precision grinding in high-tech fields such as automobiles, ships, and aerospace is getting higher and higher. Contact force control during the grinding process is the key to achieving high-precision grinding. Since grinding and polishing is a material removal process, in order to prevent irreversible damage to the workpiece surface, the grinding equipment needs to have good flexibility. Grinding equipment driven by double-acting cylinders has been widely used in the grinding field due to its good flexibility. However, the hysteresis nonlinearity between air pressure and contact force in the equipment poses a huge challenge to contact force control.

[0003] The early control scheme was to install a force sensor at the end of the grinding equipment to measure the contact force on the end of the grinding equipment in real time, and feed the value of the force sensor back to the controller to achieve closed-loop force control. However, in this control scheme, the output force of the grinding equipment needs to be used as the controlled quantity when modeling the system dynamically. The order of the established dynamic model is relatively high, which brings difficulties to the design and implementation of the control algorithm.

[0004] The existing technical research adopts the "planning + control" solution, which has achieved good results in the force control of the grinding equipment driven by the double-acting cylinder, and there is no need to install a force sensor during grinding, which can reduce the hardware cost. Specifically, the non-rate-dependent hysteresis model is first used to fit the hysteresis nonlinearity of the air pressure and force as accurately as possible, and the inverse model of the hysteresis model is constructed. Then, the expected air pressure is planned by the inverse model according to the expected contact force, and finally the planned expected air pressure is used as the controlled quantity. However, the hysteresis nonlinearity is usually rate-dependent. When the frequency of the expected force signal changes, it is difficult for the non-rate-dependent hysteresis model to accurately fit the hysteresis nonlinearity, which inevitably leads to the deterioration of the force control accuracy. In addition, the existing research scheme cannot achieve the preset tracking performance control of the air pressure when controlling the air pressure, nor can it achieve the convergence of all signals in the closed-loop system to a small neighborhood of the origin within a manually preset time. Summary of the invention

[0005] The present application provides a method for robust force control of a pneumatic grinding device with a predefined time and preset performance, aiming to achieve fast and high-precision robust force control of the pneumatic grinding device.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A method for robust force control of a pneumatic grinding device with a predefined time and preset performance, comprising:

[0008] Determining a desired force signal based on a correlation relationship between the first force and the second force;

[0009] Based on the desired force signal as an input of a rate-dependent inverse hysteresis model, a desired air pressure output by the rate-dependent inverse hysteresis model is obtained; the rate-dependent inverse hysteresis model is used to compensate for the nonlinear asymmetric hysteresis characteristics between the desired air pressure and the desired force signal;

[0010] Based on the expected air pressure, in combination with a preset practical predefined time disturbance observer, a practical predefined time controller is constructed; the practical predefined time disturbance observer is used to control the disturbance observation error to converge to a specified interval within a first specified time; the practical predefined time controller is used to control the air pressure tracking error to converge to the specified interval within a second specified time; the air pressure tracking error represents the difference between the expected air pressure and the actual air pressure; the actual air pressure represents the intake pressure of the double-acting cylinder in the pneumatic grinding equipment;

[0011] The practical predefined time controller is used to control the opening of the proportional pressure regulating valve so that the first force meets the expected value of the first force; the proportional pressure regulating valve is used to respond to the control signal input by the practical predefined time controller to control the intake pressure to adjust the output force of the pneumatic grinding equipment.

[0012] Optionally, determining the expected force signal based on the correlation between the first force and the second force includes:

[0013] Based on the dynamic model of the pneumatic grinding device, a correlation relationship between the first force and the second force is obtained; the first force represents the contact force between the tool head of the pneumatic grinding device and the workpiece; the second force represents the sum of the output force of the pneumatic grinding device and the friction force of the workpiece surface;

[0014] Based on the association relationship, determining an expected force corresponding to an expected value of the first force;

[0015] Based on the expected force, an expected force signal is determined.

[0016] Optionally, the rate-dependent inverse hysteresis model includes a multi-stage multiplication structure, which includes a rate-dependent play operator, a dead zone operator and a high-order polynomial; wherein the rate-dependent play operator is used to describe the rate-dependent nonlinear hysteresis characteristics between the expected air pressure and the expected force signal; the dead zone operator and the high-order polynomial are both used to describe the asymmetric hysteresis characteristics between the expected air pressure and the expected force signal.

[0017] Optionally, in the multi-stage multiplication structure, the rate-dependent play operator and the dead zone operator form a series structure, and the high-order polynomial and the series structure form a parallel structure.

[0018] A predefined time preset performance robust force control device for pneumatic grinding equipment, comprising:

[0019] a signal determination unit, configured to determine a desired force signal based on a correlation relationship between the first force and the second force;

[0020] an air pressure planning unit, configured to use the desired force signal as an input of a rate-dependent inverse hysteresis model to obtain a desired air pressure output by the rate-dependent inverse hysteresis model; the rate-dependent inverse hysteresis model is configured to compensate for a nonlinear asymmetric hysteresis characteristic between the desired air pressure and the desired force signal;

[0021] A controller construction unit is used to construct a practical predefined time controller based on the expected air pressure and in combination with a practical predefined time disturbance observer; the practical predefined time disturbance observer is used to control the disturbance observation error to converge to a specified interval within a first specified time; the practical predefined time controller is used to control the air pressure tracking error to converge to the specified interval within a second specified time; the air pressure tracking error represents the difference between the expected air pressure and the actual air pressure; the actual air pressure represents the intake pressure of the double-acting cylinder in the pneumatic grinding device;

[0022] An opening control unit is used to control the opening of a proportional pressure regulating valve using the practical predefined time controller so that the first force meets the expected value of the first force; the proportional pressure regulating valve is used to respond to a control signal input by the practical predefined time controller to control the intake pressure so as to adjust the output force of the pneumatic grinding equipment.

[0023] Optionally, the signal determination unit is specifically used to:

[0024] Based on the dynamic model of the pneumatic grinding device, a correlation relationship between the first force and the second force is obtained; the first force represents the contact force between the tool head of the pneumatic grinding device and the workpiece; the second force represents the sum of the output force of the pneumatic grinding device and the friction force of the workpiece surface;

[0025] Based on the association relationship, determining an expected force corresponding to an expected value of the first force;

[0026] Based on the expected force, an expected force signal is determined.

[0027] Optionally, the rate-dependent inverse hysteresis model adopted by the air pressure planning unit includes a multi-stage multiplication structure, and the multi-stage multiplication structure includes a rate-dependent play operator, a dead zone operator and a high-order polynomial; wherein the rate-dependent play operator is used to describe the rate-dependent nonlinear hysteresis characteristics between the expected air pressure and the expected force signal; the dead zone operator and the high-order polynomial are both used to describe the asymmetric hysteresis characteristics between the expected air pressure and the expected force signal.

[0028] Optionally, in the multi-stage multiplication structure, the rate-dependent play operator and the dead zone operator form a series structure, and the high-order polynomial and the series structure form a parallel structure.

[0029] A storage medium includes a stored program, wherein the program, when executed by a processor, executes the method for robust force control of a pneumatic grinding device with a predefined time and preset performance.

[0030] A pneumatic grinding device, comprising: a processor, a memory and a bus; the processor and the memory are connected via the bus;

[0031] The memory is used to store programs, and the processor is used to run programs, wherein the program, when run by the processor, executes the method for robust force control of pneumatic grinding equipment with predefined time and preset performance.

[0032] The technical solution provided by the present application determines the expected force signal based on the correlation between the first force and the second force. The expected force signal is used as the input of the rate-dependent inverse hysteresis model to obtain the expected air pressure output by the rate-dependent inverse hysteresis model. Based on the expected air pressure, a practical predefined time controller is constructed in combination with a practical predefined time disturbance observer. The opening of the proportional pressure regulating valve is controlled by using a practical predefined time controller so that the first force meets the expected value of the first force. The present application can still achieve satisfactory force control accuracy when the frequency of the expected force signal changes, and can accurately observe external disturbances within a manually specified time, thereby improving the robustness of force control, and can make the air pressure tracking error converge to a specified progress within a manually specified time, thereby improving the control accuracy and response speed of force control. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1A schematic flow chart of a method for robust force control of a pneumatic grinding device with a predefined time and preset performance provided in an embodiment of the present application;

[0035] Figure 2 A schematic flow chart of another method for robust force control of a pneumatic grinding device with a predefined time and preset performance provided in an embodiment of the present application;

[0036] Figure 3 A schematic diagram of force analysis of a pneumatic grinding device provided in an embodiment of the present application;

[0037] Figure 4 A schematic diagram of a multi-stage multiplication structure provided in an embodiment of the present application;

[0038] Figure 5 A schematic diagram of a "planning + control" logical architecture provided for an embodiment of the present application;

[0039] Figure 6 A schematic diagram of the architecture of a robust force control device with predefined time and preset performance for a pneumatic grinding device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] In this application, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0042] The existing force control method for grinding equipment driven by a double-acting cylinder as shown in the background technology has the following disadvantages: (1) In the "planning part", the existing technologies are all based on non-rate-dependent hysteresis models. When the frequency of the desired force signal changes, the force control accuracy of the existing technologies will deteriorate; (2) In terms of the anti-disturbance effect of the "control" part, the observation error of the existing technology for disturbances is often uniformly bounded or asymptotically stable, and it is impossible to achieve accurate observation of external disturbances within a manually specified time; (3) In terms of the tracking effect of the "control" part, a practical predefined time controller is designed based on preset performance to achieve the convergence of the air pressure tracking error to a manually specified accuracy within a manually specified time.

[0043] In summary, the embodiments of the present application provide a predefined time preset performance robust force control method for pneumatic grinding equipment, which is used to solve the following technical problems: (1) It is impossible to compensate for the rate-dependent hysteresis nonlinearity between air pressure (i.e., the intake pressure of the double-acting cylinder) and contact force; (2) It is impossible to effectively observe and compensate for external disturbances within a specified time; (3) It is impossible to make the air pressure tracking error converge to a specified accuracy within a manually specified time.

[0044] like Figure 1 As shown, it is a flow chart of a method for robust force control of a pneumatic grinding device with a predefined time and preset performance provided in an embodiment of the present application, which includes the following steps.

[0045] S101: Determine a desired force signal based on a correlation relationship between a first force and a second force.

[0046] The correlation between the first force and the second force can be determined based on a mechanical analysis of the pneumatic grinding equipment when grinding the workpiece.

[0047] Optionally, based on the correlation between the first force and the second force, the process of determining the desired force signal can be seen in Figure 2 The steps are shown and the corresponding explanations.

[0048] S102: Taking the expected force signal as an input of the rate-dependent inverse hysteresis model to obtain an expected air pressure output by the rate-dependent inverse hysteresis model.

[0049] The rate-dependent inverse hysteresis model is used to compensate for the nonlinear asymmetric hysteresis characteristics between the desired air pressure and the desired force signal.

[0050] Optionally, the rate-dependent inverse hysteresis model includes a multi-stage multiplication structure, which includes a rate-dependent play operator, a dead zone operator and a high-order polynomial, wherein the rate-dependent play operator is used to describe the rate-dependent nonlinear hysteresis characteristics between the expected air pressure and the expected force signal, and the dead zone operator and the high-order polynomial are both used to describe the asymmetric hysteresis characteristics between the expected air pressure and the expected force signal.

[0051] Optionally, in a multi-stage multiplication structure, the rate-dependent play operator and the dead zone operator form a series structure, and the high-order polynomial and the series structure form a parallel structure.

[0052] In some examples, multi-stage multiplication structures can be found in Figure 4 As shown, in Figure 4 In the architecture shown, is the design parameter.

[0053] In some examples, the expression of the rate-dependent inverse hysteresis model can be shown in formula (5).

[0054] (5)

[0055] In formula (5), is a high-order polynomial, is the weight, , is the dead zone operator and is defined as formula (6).

[0056] (6)

[0057] In formula (6), is the threshold of the dead zone operator, is a positive constant, ,in, is the rate-dependent play operator and is defined as formula (7).

[0058] (7)

[0059] In formula (7), is the threshold of the rate-dependent play operator, , as well as are all constants.

[0060] It can be understood that, through the rate-dependent inverse hysteresis model shown in formula (5), in the "planning" part, when the frequency of the desired force signal changes, satisfactory force control accuracy can still be achieved.

[0061] S103: Based on the expected air pressure and in combination with the practical predefined time disturbance observer, a practical predefined time controller is constructed.

[0062] Among them, a practical predefined time disturbance observer is used to control the disturbance observation error to converge to a specified interval within a first specified time, and a practical predefined time controller is used to control the air pressure tracking error to converge to a specified interval within a second specified time. The air pressure tracking error represents the difference between the expected air pressure and the actual air pressure, and the actual air pressure represents the intake pressure of the double-acting cylinder in the pneumatic grinding equipment.

[0063] In some examples, the expression of the practical predefined time disturbance observer can be shown in formula (8).

[0064] (8)

[0065] In formula (8), , , , , , , , , , , , , , , can all be considered as design parameters.

[0066] It should be noted that based on the practical predefined time disturbance observer shown in formula (8), the disturbance observation error can be reduced to time (i.e., the first specified time) converges to a small neighborhood (i.e., the specified interval) of the origin, It can be set by technicians according to actual conditions.

[0067] It can be understood that, through the practical predefined time disturbance observer shown in formula (8), it is possible to achieve accurate observation of external disturbances within a human-specified time in terms of the anti-disturbance effect of the "control" part.

[0068] In some examples, the expression of the practical predefined time controller can be shown in formula (9).

[0069] (9)

[0070] In formula (9), , , , , , , , , , , , , , , , , , , , , can be considered as design parameters, and The expression of can also be found in formula (10).

[0071] (10)

[0072] In formula (10), , . Further, let , then the designed practical predefined time controller can make the pressure tracking error exist time (i.e., the second specified time) converges to a small neighborhood of the origin (i.e., the specified interval), and when When the pressure tracking error Can always be constrained to a specified precision Inside.

[0073] It can be understood that the practical predefined time controller shown in formula (9) can achieve the tracking effect of the "control" part, and make the air pressure tracking error converge to the manually specified accuracy within the manually specified time.

[0074] S104: Using a practical predefined time controller, controlling the opening of the proportional pressure regulating valve so that the first acting force satisfies an expected value of the first acting force.

[0075] The proportional pressure regulating valve is used to respond to the control signal input by the practical predefined time controller to control the intake pressure to adjust the output force of the pneumatic grinding device. It can be understood that by adjusting the output force of the pneumatic grinding device, the first force will also change indirectly, so that the first force meets the expected value of the first force.

[0076] In some examples, the expected value of the first force is an empirical value artificially set during the grinding process to meet the best grinding effect.

[0077] In some examples, after obtaining the desired force signal, the desired force signal is used as the input of the rate-dependent inverse hysteresis model to plan the desired air pressure. In the control part, based on the desired air pressure, a practical predefined time controller is constructed in combination with a practical predefined time disturbance observer and a preset performance technology. The practical predefined time controller then acts on a proportional pressure regulating valve to achieve control of the intake pressure.

[0078] In a possible implementation manner, the logical architecture of "planning + control" shown in the embodiment of the present application can be found in Figure 5 shown.

[0079] The process shown in S101-S104 above utilizes the rate-dependent inverse hysteresis model, so that when the frequency of the desired force signal changes, the control method can still achieve satisfactory force control accuracy. By utilizing a practical predefined time disturbance observer, external disturbances can be accurately observed within a manually specified time, thereby improving the robustness of force control. By utilizing a practical predefined time controller, the air pressure tracking error can be converged to a specified accuracy within a manually specified time, thereby improving the control accuracy and response speed of force control.

[0080] like Figure 2 As shown, it is a flow chart of another method for robust force control of a pneumatic grinding device with a predefined time and preset performance provided in an embodiment of the present application, which includes the following steps.

[0081] S201: Based on a dynamic model of the pneumatic grinding equipment, a correlation relationship between the first force and the second force is obtained.

[0082] The first force represents the contact force between the tool head of the pneumatic grinding device and the workpiece, and the second force represents the sum of the output force of the pneumatic grinding device and the friction force on the surface of the workpiece.

[0083] In some examples, when the pneumatic grinding equipment is grinding the workpiece, the force of the pneumatic grinding equipment can be seen in Figure 3 As shown. Figure 3 In the scenario shown, represents the contact force, Represents the output force of the pneumatic grinding equipment, represents the friction force, and Both represent the quality of the cutter head components. represents the angle between the contact force and gravity, Represents the intake pressure (which can be understood as the cylinder pressure), Represents the outlet pressure (which can be understood as the cylinder exhaust pressure), Represents the displacement of the cylinder piston.

[0084] In a possible implementation, based on the force conditions of the pneumatic grinding equipment, the proportional pressure regulating valve can be modeled as shown in formula (1) using a second-order transfer function.

[0085] (1)

[0086] In formula (1), is the transfer function, is the system output (i.e., intake pressure), For system input, is a complex variable in frequency, , as well as Design parameters. The so-called design parameters can be understood as a series of design requirements and technical parameters specified according to the purpose and performance indicators of pneumatic grinding equipment during the production of pneumatic grinding equipment.

[0087] Furthermore, considering external disturbances In the case of Figure 3 In the scenario shown, the dynamic modeling of the pneumatic grinding equipment is shown in formula (2).

[0088] (2)

[0089] In some examples, let , , then formula (2) can be transformed into formula (3).

[0090] (3)

[0091] In formula (3), Furthermore, based on formula (2) and formula (3), the dynamic model of the pneumatic grinding device can be determined, and according to the dynamic model, the correlation relationship between the first force and the second force can be obtained.

[0092] S202: Based on the association relationship, determine an expected force corresponding to the expected value of the first force.

[0093] After obtaining the correlation between the first force and the second force, a planning formula for the desired force can be determined based on the correlation. The planning formula can be shown in formula (4).

[0094] (4)

[0095] In formula (4), represents the expected force, Represents the expected value of the first force (which can be understood as the expected value of the contact force).

[0096] S203: Determine the expected force signal based on the expected force.

[0097] The expected force calculated by formula (4) is , determined as an expected force signal, which is obviously rate-related. The so-called rate-related can be understood as: the frequency of the expected force signal is not a fixed frequency, but changes with the change of the scene or application scope.

[0098] The process shown in S201-S203 above can obtain the rate-related expected force signal through the dynamic model of the pneumatic grinding equipment, and provide an effective input signal for the subsequent "planning" related hysteresis model.

[0099] like Figure 6 As shown, it is a schematic diagram of the architecture of a predefined time preset performance robust force control device for a pneumatic grinding device provided in an embodiment of the present application, including the modules shown below.

[0100] The signal determination unit 100 is used to determine the expected force signal based on the correlation relationship between the first force and the second force.

[0101] Optionally, the signal determination unit 100 is specifically used to: obtain a correlation relationship between the first force and the second force based on a dynamic model of the pneumatic grinding device; the first force represents the contact force between the tool head of the pneumatic grinding device and the workpiece; the second force represents the sum of the output force of the pneumatic grinding device and the friction force of the workpiece surface; based on the correlation relationship, determine the expected force corresponding to the expected value of the first force; based on the expected force, determine it as an expected force signal.

[0102] The air pressure planning unit 200 is used to obtain the desired air pressure output by the rate-dependent inverse hysteresis model based on the desired force signal as the input of the rate-dependent inverse hysteresis model; the rate-dependent inverse hysteresis model is used to compensate for the nonlinear asymmetric hysteresis characteristics between the desired air pressure and the desired force signal.

[0103] Optionally, the rate-dependent inverse hysteresis model adopted by the air pressure planning unit 200 includes a multi-stage multiplication structure, which includes a rate-dependent play operator, a dead zone operator and a high-order polynomial; wherein the rate-dependent play operator is used to describe the rate-dependent nonlinear hysteresis characteristics between the desired air pressure and the desired force signal; the dead zone operator and the high-order polynomial are both used to describe the asymmetric hysteresis characteristics between the desired air pressure and the desired force signal.

[0104] Optionally, in a multi-stage multiplication structure, the rate-dependent play operator and the dead zone operator form a series structure, and the high-order polynomial and the series structure form a parallel structure.

[0105] The controller construction unit 300 is used to construct a practical predefined time controller based on the expected air pressure in combination with a practical predefined time disturbance observer; the practical predefined time disturbance observer is used to control the disturbance observation error to converge to a specified interval within a first specified time; the practical predefined time controller is used to control the air pressure tracking error to converge to a specified interval within a second specified time; the air pressure tracking error represents the difference between the expected air pressure and the actual air pressure; the actual air pressure represents the intake pressure of the double-acting cylinder in the pneumatic grinding equipment.

[0106] The opening control unit 400 is used to control the opening of the proportional pressure regulating valve using a practical predefined time controller so that the first force meets the expected value of the first force; the proportional pressure regulating valve is used to respond to the control signal input by the practical predefined time controller to control the intake pressure to adjust the output force of the pneumatic grinding equipment.

[0107] The modules shown above utilize the rate-dependent inverse hysteresis model, which enables the control method to still achieve satisfactory force control accuracy when the frequency of the desired force signal changes. The practical predefined time disturbance observer can accurately observe the external disturbance within the manually specified time, thereby improving the robustness of the force control. The practical predefined time controller can make the air pressure tracking error converge to the specified progress within the manually specified time, thereby improving the control accuracy and response speed of the force control.

[0108] The present application also provides a computer-readable storage medium, which includes a stored program, wherein the program executes the predefined time preset performance robust force control method for pneumatic grinding equipment provided by the present application.

[0109] The present application also provides a pneumatic grinding device, including: a processor, a memory and a bus. The processor and the memory are connected via a bus, the memory is used to store a program, and the processor is used to run the program, wherein the predefined time preset performance robust force control method of the pneumatic grinding device provided by the present application is executed when the program is run.

[0110] In addition, the functions described above in the embodiments of the present application may be at least partially performed by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0111] Although several specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present application. Certain features described in the context of a separate embodiment can also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0112] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of disclosure involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other to form a technical solution.

Claims

1. A method for robust force control of a pneumatic grinding device with a predefined time and preset performance, characterized in that: include: Determining a desired force signal based on a correlation relationship between the first force and the second force; Based on the desired force signal as an input of a rate-dependent inverse hysteresis model, a desired air pressure output by the rate-dependent inverse hysteresis model is obtained; the rate-dependent inverse hysteresis model is used to compensate for the nonlinear asymmetric hysteresis characteristics between the desired air pressure and the desired force signal; Based on the desired air pressure, in combination with a practical predefined time disturbance observer, a practical predefined time controller is constructed; the practical predefined time disturbance observer is used to control the disturbance observation error to converge to a specified interval within a first specified time; the practical predefined time controller is used to control the air pressure tracking error to converge to the specified interval within a second specified time; The air pressure tracking error represents the difference between the desired air pressure and the actual air pressure; the actual air pressure represents the intake pressure of the double-acting cylinder in the pneumatic grinding device; The practical predefined time controller is used to control the opening of the proportional pressure regulating valve so that the first force meets the expected value of the first force; the proportional pressure regulating valve is used to respond to the control signal input by the practical predefined time controller to control the intake pressure to adjust the output force of the pneumatic grinding equipment.

2. The method according to claim 1, characterized in that Determining the expected force signal based on the correlation between the first force and the second force includes: Based on the dynamic model of the pneumatic grinding device, a correlation relationship between the first force and the second force is obtained; the first force represents the contact force between the tool head of the pneumatic grinding device and the workpiece; the second force represents the sum of the output force of the pneumatic grinding device and the friction force of the workpiece surface; Based on the association relationship, determining an expected force corresponding to an expected value of the first force; Based on the expected force, an expected force signal is determined.

3. The method according to claim 1, characterized in that The rate-dependent inverse hysteresis model includes a multi-stage multiplication structure, which includes a rate-dependent play operator, a dead zone operator and a high-order polynomial; wherein the rate-dependent play operator is used to describe the rate-dependent nonlinear hysteresis characteristics between the expected air pressure and the expected force signal; the dead zone operator and the high-order polynomial are both used to describe the asymmetric hysteresis characteristics between the expected air pressure and the expected force signal.

4. The method according to claim 3, characterized in that In the multi-stage multiplication structure, the rate-dependent play operator and the dead zone operator form a series structure, and the high-order polynomial and the series structure form a parallel structure.

5. A predefined time preset performance robust force control device for pneumatic grinding equipment, characterized in that: include: a signal determination unit, configured to determine a desired force signal based on a correlation relationship between the first force and the second force; an air pressure planning unit, configured to use the desired force signal as an input of a rate-dependent inverse hysteresis model to obtain a desired air pressure output by the rate-dependent inverse hysteresis model; the rate-dependent inverse hysteresis model is configured to compensate for a nonlinear asymmetric hysteresis characteristic between the desired air pressure and the desired force signal; A controller construction unit, configured to construct a practical predefined time controller based on the desired air pressure and in combination with a practical predefined time disturbance observer; the practical predefined time disturbance observer is configured to control the disturbance observation error to converge to a specified interval within a first specified time; the practical predefined time controller is configured to control the air pressure tracking error to converge to the specified interval within a second specified time; The air pressure tracking error represents the difference between the desired air pressure and the actual air pressure; the actual air pressure represents the intake pressure of the double-acting cylinder in the pneumatic grinding device; An opening control unit is used to control the opening of a proportional pressure regulating valve using the practical predefined time controller so that the first force meets the expected value of the first force; the proportional pressure regulating valve is used to respond to a control signal input by the practical predefined time controller to control the intake pressure so as to adjust the output force of the pneumatic grinding equipment.

6. The device according to claim 5, characterized in that The signal determination unit is specifically used for: Based on the dynamic model of the pneumatic grinding device, a correlation relationship between the first force and the second force is obtained; the first force represents the contact force between the tool head of the pneumatic grinding device and the workpiece; the second force represents the sum of the output force of the pneumatic grinding device and the friction force of the workpiece surface; Based on the association relationship, determining an expected force corresponding to an expected value of the first force; Based on the expected force, an expected force signal is determined.

7. The device according to claim 5, characterized in that The rate-dependent inverse hysteresis model adopted by the air pressure planning unit includes a multi-stage multiplication structure, which includes a rate-dependent play operator, a dead zone operator and a high-order polynomial; wherein the rate-dependent play operator is used to describe the rate-dependent nonlinear hysteresis characteristics between the expected air pressure and the expected force signal; the dead zone operator and the high-order polynomial are both used to describe the asymmetric hysteresis characteristics between the expected air pressure and the expected force signal.

8. The device according to claim 7, characterized in that In the multi-stage multiplication structure, the rate-dependent play operator and the dead zone operator form a series structure, and the high-order polynomial and the series structure form a parallel structure.

9. A storage medium, characterized in that: The storage medium includes a stored program, wherein the program, when executed by a processor, executes the predefined time preset performance robust force control method for a pneumatic grinding device according to any one of claims 1 to 4.

10. A pneumatic grinding device, characterized in that: include: processor, memory, and bus; The processor is connected to the memory via the bus; The memory is used to store programs, and the processor is used to run programs, wherein the program, when run by the processor, executes the predefined time preset performance robust force control method of a pneumatic grinding device as described in any one of claims 1-4.

Images