A control method of an end effector, a mechanical device, an electronic device, and a storage medium

Abstract

The application discloses a control method of an end effector, a mechanical device, an electronic device and a storage medium, and belongs to the technical field of automation control. The control method of the end effector comprises the following steps: acquiring an actual output force collected by a force sensor; acquiring a pipeline internal pressure collected by a pressure sensor; calculating an indirect force according to the pipeline internal pressure; determining an output error according to a difference between the actual output force and a target force; setting weight information according to the output error; determining an adjustment parameter based on the weight information, the actual output force, the indirect force and the target force; and controlling the pressure adjusting device to work according to the adjustment parameter, so that the end effector works according to the target force. The application can accurately control the end effector to output stable force.

Description

Technical Field

[0001] The present application relates to the field of automation control technology, and in particular to a control method, mechanical equipment, electronic equipment, and storage medium for an end effector. Background Art

[0002] Mechanical equipment such as CNC machine tools and stamping equipment have end effectors. End effectors suitable for force-stabilized control processing can perform surface strengthening treatment on the workpiece surface according to the set force.

[0003] During workpiece surface hardening by an end effector, a stable force output is required to ensure machining quality. In related technologies, a force sensor is typically installed on the surface where the end effector contacts the load, and the output force of the end effector is adjusted based on the force sensor's measured value. However, this adjustment method is susceptible to the combined effects of pressure transmission delay and sudden load changes, leading to overshoot. Furthermore, the force sensor's measured value is susceptible to interference, resulting in low control accuracy.

[0004] Therefore, how to accurately control the end effector to output a stable force is a technical problem that those skilled in the art currently need to solve. Summary of the Invention

[0005] The purpose of this application is to provide a control method, mechanical equipment, electronic equipment and storage medium for an end effector, which can accurately control the end effector to output a stable force.

[0006] To solve the above technical problems, the present application provides a control method for an end effector, which is applied to a controller of a mechanical device. The control method for the end effector includes:

[0007] Step 1: Obtaining the actual output force collected by the force sensor; obtaining the pressure in the pipeline collected by the pressure sensor, and calculating the indirect force based on the pressure in the pipeline; wherein the indirect force is the force exerted by the fluid on the end effector;

[0008] Step 2: Determine an output error based on the difference between the actual output force and the target force, and set weight information based on the output error; wherein the weight information includes a first weight corresponding to the force sensor and a second weight corresponding to the pressure sensor;

[0009] Step 3: determining an adjustment parameter based on the weight information, the actual output force, the indirect force, and the target force;

[0010] Step 4: Control the pressure regulating device to operate according to the regulating parameters, so that the end effector operates according to the target force.

[0011] Optionally, determining an output error according to a difference between the actual output force and the target force, and setting weight information according to the output error, includes:

[0012] setting the absolute value of the difference between the actual output force and the target force as the output error;

[0013] If the output error is less than or equal to a first threshold, setting the first weight to a first fixed value and setting the second weight to a second fixed value;

[0014] If the output error is greater than the first threshold and less than a second threshold, setting the first weight and the second weight according to the output error; wherein the first weight is negatively correlated with the output error, and the second weight is positively correlated with the output error;

[0015] If the output error is greater than a second threshold, the first weight is set to a third fixed value and the second weight is set to a fourth fixed value; wherein the first fixed value is greater than the third fixed value and the second fixed value is less than the fourth fixed value.

[0016] Optionally, determining an adjustment parameter based on the weight information, the actual output force, the indirect force, and the target force includes:

[0017] Taking the difference between the target force and the actual output force as a first error;

[0018] taking the difference between the target force and the indirect force as a second error;

[0019] Performing weighted calculation on the first error and the second error based on the weight information to obtain a proportional term;

[0020] Performing differential calculation on the first error to obtain a differential term;

[0021] The adjustment parameter is determined according to the proportional term and the differential term.

[0022] Optionally, the calculation formula of the proportional term P is: , Represents the proportional gain, represents the first weight, Indicates the target force, Indicates the actual output force, represents the second weight, Indicates indirect force;

[0023] The calculation formula of the differential term D is: , represents the differential gain, represents the differential of the first error, and dt represents the differential of time;

[0024] The adjustment parameters .

[0025] Optionally, before setting weight information according to the output error, the method further includes:

[0026] The absolute value of the difference between the actual output force and the indirect force is set as the system residual;

[0027] Determining whether a duration during which the system residual is continuously greater than a third threshold is greater than a first target duration;

[0028] If so, it is determined that a fault exists, and the end effector control process in the fault mode is started;

[0029] If not, proceed to the step of setting weight information according to the output error.

[0030] Optionally, the end effector control process in the fault mode includes:

[0031] determining a temporary adjustment parameter according to the actual output force or the indirect force, and controlling the pressure regulating device to operate according to the temporary adjustment parameter;

[0032] If the duration for which the system residual is continuously less than or equal to the fourth threshold is greater than the second target duration, the step of setting weight information according to the output error is entered; wherein the third threshold is greater than or equal to the fourth threshold.

[0033] Optionally, the end effector is an actuator with a built-in hydraulic cylinder;

[0034] Accordingly, the indirect force is calculated according to the pressure in the pipeline, including:

[0035] The indirect force is calculated based on the effective area of ​​the hydraulic cylinder and the pressure in the pipeline.

[0036] The present application also provides a mechanical device, comprising a controller, a pressure regulating device, a pressure sensor, an end effector, and a force sensor, wherein the end effector is a fluid-driven actuator, the pressure regulating device is connected to the end effector via a preset pipeline, the pressure regulating device is used to regulate the pressure of the fluid in the preset pipeline, the pressure sensor is disposed in the preset pipeline, and the force sensor is disposed on the contact surface between the end effector and the load;

[0037] When the controller is working, the operations performed include:

[0038] Step 1: Obtaining the actual output force collected by the force sensor; obtaining the pressure in the pipeline collected by the pressure sensor, and calculating the indirect force based on the pressure in the pipeline; wherein the indirect force is the force exerted by the fluid on the end effector;

[0039] Step 2: Determine an output error based on the difference between the actual output force and the target force, and set weight information based on the output error; wherein the weight information includes a first weight corresponding to the force sensor and a second weight corresponding to the pressure sensor;

[0040] Step 3: determining an adjustment parameter based on the weight information, the actual output force, the indirect force, and the target force;

[0041] Step 4: Control the pressure regulating device to operate according to the regulating parameters, so that the end effector operates according to the target force.

[0042] The present application also provides a storage medium on which a computer program is stored. When the computer program is executed, the steps of the control method of the end effector are implemented.

[0043] The present application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor calls the computer program in the memory, the steps of the control method of the above-mentioned end effector are implemented.

[0044] This application provides a method for controlling an end effector. A force sensor is used to obtain the actual force output by the end effector on a load. A pressure sensor is used to obtain the pressure within a pipeline and calculate an indirect force reflecting the fluid's effect on the end effector. This application also calculates the output error between the actual output force and a target force, and uses this output error to set weighting information for the force and pressure sensors. Based on this weighting information, the actual output force, the indirect force, and the target force, this application determines adjustment parameters and performs pressure regulation, ensuring that the end effector outputs a stable target force on the load. In this process, the force and pressure sensors jointly participate in the end effector control process, reducing external environmental interference with control accuracy. This application sets weighting information based on the output error, dynamically adjusting the weights of the force and pressure sensors based on actual operating conditions, reducing the impact of pressure transmission delays and sudden load changes on the end effector's control performance. Consequently, this application enables precise control of the end effector's stable force output. This application also provides a mechanical device, a storage medium, and an electronic device, all of which exhibit the aforementioned beneficial effects and are not further detailed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. 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 any creative work.

[0046] Figure 1 A flow chart of a method for controlling an end effector provided in an embodiment of the present application;

[0047] Figure 2 A schematic diagram of the relationship between the first output error and the first weight provided in an embodiment of the present application;

[0048] Figure 3 A schematic diagram of the relationship between the second output error and the first weight provided in an embodiment of the present application;

[0049] Figure 4 A schematic diagram of the relationship between the third output error and the first weight provided in an embodiment of the present application;

[0050] Figure 5 A schematic diagram of the relationship between the fourth output error and the first weight provided in an embodiment of the present application;

[0051] Figure 6 A schematic diagram of a hydraulic system provided in an embodiment of the present application;

[0052] Figure 7 A logic block diagram of a dynamic fusion hydraulic end-effector force stabilization control system provided in an embodiment of the present application;

[0053] Figure 8 A dynamic weight adjustment logic flow chart provided in an embodiment of the present application;

[0054] Figure 9 A fault detection logic diagram provided in an embodiment of the present application;

[0055] Figure 10 Another hydraulic system schematic diagram provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0057] At present, the force stability control of hydraulic or pneumatic control systems mainly relies on the traditional PID (Proportion-Integral-Differential) algorithm combined with a single sensor feedback; some improvement schemes attempt to fuse multi-sensor data, but their schemes only mix the force sensor and pressure sensor signals according to fixed weights. In addition, passive compliance control and electric drive end effectors can only be used in specific scenarios, and the applicable scenarios are relatively few. Although the above can meet some of the needs in basic control scenarios, it is limited by the strong nonlinear characteristics and complex working conditions of the hydraulic system, and there are still significant technical bottlenecks. In response to the technical problems existing in the above-mentioned related technologies, this embodiment provides a new end effector control scheme through the following embodiments, which can accurately control the end effector to output a stable force.

[0058] See below Figure 1 , Figure 1 This is a flow chart of a control method for an end effector provided in an embodiment of the present application.

[0059] Specific steps may include:

[0060] S101: Acquire the actual output force collected by the force sensor;

[0061] This embodiment can be applied to a controller for mechanical equipment, which can be any automated equipment equipped with a pressure regulating device and an end effector, such as a hydraulic press, an injection molding machine, a robotic end tool, a CNC machine tool, or engineering machinery. The end effector is a fluid-driven actuator, and the pressure regulating device is connected to the end effector via a preset pipeline, which is used to regulate the pressure of the fluid in the preset pipeline.

[0062] The mechanical device also includes a pressure sensor and a force sensor. The pressure sensor is located within the pre-set pipeline, and the force sensor is located at the interface between the end effector and the load. The pressure sensor is used to detect the pressure within the pre-set pipeline, and the force sensor is used to detect the force applied by the end effector to the load. The actual output force, indirect force, and target force mentioned in this embodiment are all values ​​used to describe the magnitude of the applied force.

[0063] In this embodiment, the end effector is a device mounted at the end of a robotic arm or actuator in a mechanical device, used to perform surface treatment on a load according to a set force. The load is the object being manipulated by the end effector, such as a workpiece such as a metal part, electronic component, or medical device.

[0064] In this embodiment, the controller can be electrically connected to the force sensor, and the controller can obtain the actual output force detected by the force sensor. This actual output force represents the actual force applied by the end effector to the load. As a feasible embodiment, the end effector can be provided with multiple force sensors, and the controller can calculate the actual output force based on the signals collected by all force sensors.

[0065] S102: Obtaining the pressure in the pipeline collected by the pressure sensor, and calculating the indirect force according to the pressure in the pipeline;

[0066] In this embodiment, the controller can be electrically connected to a pressure sensor. The controller can obtain the pipeline pressure detected by the pressure sensor. The pipeline pressure is the pressure of a predetermined fluid within the pipeline, which can be a liquid or a gas. As a feasible embodiment, multiple pressure sensors can be installed in the predetermined pipeline, and the controller can calculate the pipeline pressure based on the signals detected by all pressure sensors.

[0067] On the basis of obtaining the pressure in the pipeline, this step can calculate the force exerted by the fluid on the end effector according to the pressure in the pipeline, that is, the indirect force.

[0068] In this embodiment, the operations of S101 and S102 can be executed in a cycle to determine the latest actual output force and indirect force. After the latest actual output force and indirect force are obtained, the related operations of S103 to S105 can be executed to achieve continuous control of the end effector.

[0069] As a feasible implementation, the end effector may be an actuator with a built-in hydraulic cylinder. Accordingly, this embodiment can calculate the indirect force by the following method: calculating the indirect force based on the effective area of ​​the hydraulic cylinder and the pressure in the pipeline. The effective area of ​​the hydraulic cylinder refers to the actual area of ​​the hydraulic oil acting on the piston. In this embodiment, the effective area can be calculated based on the diameter of the hydraulic cylinder, and the product of the effective area and the pressure in the pipeline is used as the indirect force.

[0070] S103: determining an output error according to a difference between the actual output force and the target force, and setting weight information according to the output error;

[0071] Prior to this step, the target force of the end effector can also be determined. This refers to the amount of force the end effector is expected to apply to the load. This target force can be a parameter entered by the user on the operation interface, a parameter transmitted from another terminal, or a parameter calculated by the mechanical device during operation.

[0072] Among them, based on the actual output force and the target force, this step can determine the difference between the actual output force and the target force, that is, the output error. The above output error is used to describe the degree of difference between the actual output force of the end effector and the control target.

[0073] As a supplementary implementation method, a plurality of force sensors are provided on the surface of the end effector for measuring forces at different positions. The force corresponding to the measurement value of each force sensor is set as the local output force. All local output forces are evaluated, and local output forces with obvious deviations from the target force are eliminated to eliminate the influence of abnormal values ​​on the measurement results. Then, the remaining local output forces are weightedly calculated based on the positions of the force sensors, and the weighted calculation result is used as the actual output force, and the output error is determined based on the difference between the actual output force and the target force. The above method can effectively improve the accuracy and reliability of the measurement and ensure the precise control of the load output force by the end effector. The above-mentioned local output force with obvious deviations from the target force refers to: the local output force whose absolute value of the difference with the target force is greater than the critical value.

[0074] In this step, weight information can be set based on the output error. The weight information includes a first weight corresponding to the force sensor and a second weight corresponding to the pressure sensor. That is, in this step, the first weight corresponding to the force sensor and the second weight corresponding to the pressure sensor can be set based on the output error.

[0075] The above-mentioned first weight and second weight are used to determine whether to rely more on the actual output force or the indirect force during the control process, so as to flexibly adjust the control strategy according to the actual working conditions, reduce the impact of external interference and internal changes on the control effect of the end effector, and thus achieve more accurate and stable force control.

[0076] S104: determining an adjustment parameter based on the weight information, the actual output force, the indirect force, and the target force;

[0077] Among them, this step can perform weighted calculation on the actual output force, indirect force and target force based on the weight information, and then determine the adjustment parameters of the pressure regulating device according to the weighted calculation result, thereby changing the pressure in the preset pipeline.

[0078] Traditional solutions typically use a fixed-weight fusion strategy to determine adjustment parameters. However, this strategy cannot adapt to dynamic conditions, suffers from delayed response in large error scenarios, and struggles to synchronize multi-sensor data, lacking fault tolerance. The dynamic weight fusion algorithm provided in this embodiment replaces the traditional fixed-weight fusion method by combining force sensors with pressure sensors to dynamically adjust the weight information controlling the pressure regulating device. This overcomes the inadequate sensor fusion capabilities of traditional solutions.

[0079] The pressure regulating device can be a servo directional valve, a proportional pressure reducing valve, or a gas-liquid booster pump, or a combination thereof. Accordingly, the aforementioned adjustment parameter represents the control variable corresponding to the pressure regulating device, which is used to adjust the pressure within the preset pipeline to meet the end effector's requirement for stable load output.

[0080] S105: Controlling the pressure regulating device to operate according to the regulating parameters, so that the end effector operates according to the target force.

[0081] Among them, the pressure regulating device can adjust the valve opening and the pressure increase ratio according to the above-mentioned regulating parameters, and then change the fluid pressure input to the end actuator to compensate for the influence of pressure transmission delay and load mutation, so that the end actuator can output a stable force on the load, and the actual output force is equal to the target force.

[0082] This embodiment uses a force sensor to obtain the actual output force of the end effector applied to the load. It also uses a pressure sensor to obtain the pressure within the pipeline and calculate an indirect force that reflects the fluid's effect on the end effector. This embodiment also calculates the output error between the actual output force and the target force and sets weighting information for the force and pressure sensors based on this output error. This embodiment determines adjustment parameters and performs pressure regulation based on this weighting information, the actual output force, the indirect force, and the target force, ensuring that the end effector outputs a stable target force applied to the load. In this process, the force and pressure sensors jointly participate in the control of the end effector, reducing external environmental interference with control accuracy. This embodiment sets weighting information based on the output error, dynamically adjusting the weights of the force and pressure sensors based on actual operating conditions, thereby reducing the impact of pressure transmission delays and sudden load changes on the end effector's control. Therefore, this embodiment can precisely control the end effector's stable force output.

[0083] As for Figure 1 As a further introduction to the corresponding embodiment, the above embodiment can directly use the difference between the actual output force and the target force as the output error, or can set the absolute value of the difference between the actual output force and the target force as the output error.

[0084] This embodiment can pre-set the correspondence between the output error and the weight information. After determining the output error, the first weight corresponding to the force sensor and the second weight corresponding to the pressure sensor can be determined based on the above correspondence. This embodiment can determine the correspondence between the output error and the weight information based on the test data through actual testing or simulation testing of the mechanical equipment. This embodiment adopts a dynamic weight fusion architecture that uses a combination of force sensors and pressure sensors, and proposes an adjustment mechanism for the first weight (i.e., the force sensor influence factor) and the second weight (i.e., the pressure sensor influence factor) that is adaptive based on the output error (i.e., the error range). This can avoid overshoot caused by the superposition of hydraulic pipeline pressure transmission delay and load mutation, and solve the problems of rigid fusion strategy and delayed dynamic response in traditional solutions.

[0085] In this embodiment, it can be specified that both the first weight and the second weight are greater than 0, and the sum of the first weight and the second weight is a fixed value, such as 1. Therefore, the correspondence between the output error and the weight information can be the correspondence between the output error and the first weight. After determining the first weight, the fixed value can be subtracted from the first weight to obtain the second weight. Similarly, the correspondence between the output error and the weight information can also be the correspondence between the output error and the second weight.

[0086] As a feasible implementation method, this embodiment can use a decreasing function to describe the corresponding relationship between the output error and the first weight; see Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the relationship between the first output error and the first weight provided in an embodiment of the present application. Figure 3 This is a schematic diagram of the relationship between the second output error and the first weight provided in the embodiment of the present application. The horizontal axis in the figure is the output error, and the vertical axis is the first weight. .

[0087] As a feasible implementation method, this embodiment can use a piecewise function to describe the corresponding relationship between the output error and the first weight; see Figure 4 , Figure 4 This is a schematic diagram of the relationship between the third output error and the first weight provided in the embodiment of the present application. The horizontal axis in the figure is the output error, and the vertical axis is the first weight. .

[0088] Specifically, in this embodiment, the weight information can be set in the following manner:

[0089] If the output error is less than or equal to a first threshold, setting the first weight to a first fixed value and setting the second weight to a second fixed value;

[0090] If the output error is greater than the first threshold and less than a second threshold, setting the first weight and the second weight according to the output error; wherein the first weight is negatively correlated with the output error, and the second weight is positively correlated with the output error;

[0091] If the output error is greater than a second threshold, the first weight is set to a third fixed value and the second weight is set to a fourth fixed value; wherein the first fixed value is greater than the third fixed value and the second fixed value is less than the fourth fixed value.

[0092] Before this step, the target force of the end effector can also be determined , that is, the force that the end effector needs to apply to the load. The first threshold and the second threshold can be calculated based on the target force. Set, if the first threshold is 2 , the second threshold is 5 , the first fixed value is 0.8, the second fixed value is 0.2, the third fixed value is 0.2, and the fourth fixed value is 0.8. The relationship between the output error and the first weight is as follows: Figure 5 As shown, Figure 5 This is a schematic diagram of the relationship between the fourth output error and the first weight provided in an embodiment of the present application.

[0093] Due to the different settings, there is a contradiction between the accuracy and response speed of the force sensor and the pressure sensor, that is, the force sensor has high accuracy but has a delay, and the pressure sensor has a fast response but is easily interfered by pipeline noise. By setting the first weight and the second weight as described above, the advantages of the force sensor and the pressure sensor can be combined to achieve high-precision, low-latency, and anti-interference end effector control. In addition, in the hydraulic control scenario, there are situations where changes in oil temperature cause valve flow gain drift, and the high-frequency noise of the pressure sensor reduces the signal-to-noise ratio. This embodiment can dynamically set the weights of the force sensor and the pressure sensor according to the actual working conditions, and can effectively deal with multi-source noise interference.

[0094] As for Figure 1Further introduction to the corresponding embodiment: In the related art, PID algorithm is usually used to realize the control of the pressure regulating device, but the above method is easily affected by nonlinear interference. For example, the dead zone of the hydraulic valve and the compressibility of the oil will cause the force-displacement relationship to present nonlinear characteristics, which makes it difficult for the traditional PID algorithm to achieve accurate modeling. In addition, the integral term of the PID algorithm is prone to saturation when faced with the dead zone of the hydraulic valve and friction nonlinearity, thereby causing overshoot and continuous oscillation problems. At the same time, although Model Predictive Control (MPC) has high control accuracy, it relies on an accurate system model and has high computational complexity, making it difficult to meet the requirements of real-time operation.

[0095] To address the problems of the aforementioned PID algorithm, such as rigid control algorithm and the risk of integral saturation, this application provides a solution for determining the adjustment parameters of a pressure regulating device based on a PD (proportional-differential) algorithm. The specific process is as follows:

[0096] Step A1: Determine the target force of the end effector.

[0097] Step A2: taking the difference between the target force and the actual output force as a first error.

[0098] Step A3: taking the difference between the target force and the indirect force as the second error.

[0099] Step A4: performing weighted calculation on the first error and the second error based on the weight information to obtain a proportional term.

[0100] Specifically, the calculation formula of the proportional term P is: , Represents the proportional gain, represents the first weight, Indicates the target force, Indicates the actual output force, represents the second weight, Indicates indirect force. As a feasible implementation method, + =1, Dynamically adjusted according to the size of the output error.

[0101] Step A5: performing differential calculation on the first error to obtain a differential term.

[0102] Specifically, the calculation formula of the differential term D is: , represents the differential gain, represents the differential of the first error, and dt represents the differential of time.

[0103] Step A6: Determine the adjustment parameter according to the proportional term and the differential term.

[0104] Specifically, adjust the parameters The calculation formula is as follows:

[0105] .

[0106] This solution implements a de-integrated PD control design, eliminates the integral term of the traditional PID algorithm, solves the integral saturation problem caused by nonlinear characteristics of the hydraulic system (such as valve dead zone and friction), and is superior to the effect of the traditional PID algorithm with the integral term.

[0107] As for Figure 1 Further introduction to the corresponding embodiment: before setting the weight information according to the output error, fault detection can also be performed in the following way: setting the absolute value of the difference between the actual output force and the indirect force as the system residual; judging whether the time duration for which the system residual is continuously greater than the third threshold is greater than the first target time duration; if so, determining that a fault exists, and starting the end effector control process in the fault mode; if not, entering the step of setting the weight information according to the output error.

[0108] Specifically, this embodiment can start the first timer when the system residual is greater than the third threshold, and turn off the first timer and reset the first timer when the system residual is less than or equal to the third threshold; the time recorded by the first timer is the duration during which the system residual continues to be greater than the third threshold. If the duration is greater than the first target duration, it is determined that a fault exists, so as to start the control process of the end effector in the fault mode.

[0109] In related technologies, single-sensor solutions lack redundant design, and the system cannot degrade to lower levels when a sensor fails, resulting in processing interruption. To address this issue, this embodiment provides a control process for the end effector in failure mode, specifically including: determining a temporary adjustment parameter based on the actual output force or the indirect force, and controlling the pressure regulating device to operate according to the temporary adjustment parameter; if the system residual is continuously less than or equal to the fourth threshold for a period longer than a second target duration, then proceeding to the step of setting weight information based on the output error. The third threshold is greater than or equal to the fourth threshold.

[0110] In this embodiment, the second timer can be started when the system residual is less than or equal to the fourth threshold, and the second timer can be turned off and reset when the system residual is greater than the fourth threshold; the time recorded by the second timer is the duration during which the system residual is continuously less than or equal to the fourth threshold. If the duration is greater than the second target duration, it indicates that the fault has been recovered, and the step of setting weight information according to the output error can be entered.

[0111] Specifically, during a fault, this embodiment can use only the actual output force to determine the temporary adjustment parameters and control the pressure regulating device to operate according to the temporary adjustment parameters, or it can use only the indirect force to determine the temporary adjustment parameters and control the pressure regulating device to operate according to the temporary adjustment parameters. If the temporary adjustment parameters are determined based on the actual output force, it is equivalent to setting the first weight to 1 and the second weight to 0; if the temporary adjustment parameters are determined based on the indirect force, it is equivalent to setting the first weight to 0 and the second weight to 1. This solution can overcome the shortcomings of insufficient reliability and adaptability in related technologies.

[0112] This embodiment provides a control logic that integrates residual detection and mode switching. Specifically, if the system residual remains greater than a third threshold for a period greater than a first target duration, a fault is determined to exist, the first weight is set to 0, and the second weight is set to 1. At this point, only the pressure sensor operates, maintaining rapid control response. If the system residual remains less than or equal to the fourth threshold for a period greater than the second target duration, the fault is resolved and the system switches back to normal mode. This dual-sensor fusion fault handling method integrates residual detection and degraded control logic. In the event of a force sensor failure, the system switches to a pure pressure sensor feedback mode, maintaining basic system functionality and improving the reliability of end-effector control.

[0113] The process described in the above embodiment is explained below through an embodiment in actual application.

[0114] This embodiment provides a hydraulic end-effector force stabilization control system and method based on dual-sensor dynamic fusion, which is suitable for a force stabilization control processing method for workpiece surface enhancement and can perform surface treatment on the workpiece according to a set force value. This embodiment can be widely used in intelligent manufacturing fields such as CNC machine tools and stamping equipment that require precise force control.

[0115] See Figure 6 , Figure 6 A schematic diagram of a hydraulic system provided in an embodiment of the present application is shown below. Figure 1The mechanical equipment described in the corresponding embodiments may also include the aforementioned hydraulic system, which includes a hydraulic housing 1, a pump 2, a relief valve 3, a gas-liquid booster pump 4, a three-position, four-way reversing valve 5, a pressure sensor 6, a flow control valve 7, an end effector 8, a force sensor 9, an air tank 10, an air pressure proportional valve 11, and a proportional pressure reducing valve 12. Hydraulic oil is delivered by the pump 2 and passes through the relief valve 3 for initial system pressure regulation. The relief valve 3 has a built-in pressure sensor M that displays the currently adjusted pressure value. The hydraulic oil then passes through the gas-liquid booster pump 4 to achieve system pressure boosting. The pressure sensor behind the gas-liquid booster pump 4 reads the boosted pressure value. The hydraulic oil then passes through the three-position, four-way reversing valve 5 to achieve the switching function of the end effector 8, thereby controlling the movement of the end effector 8. After the three-position, four-way reversing valve 5, the hydraulic oil enters the proportional pressure reducing valve 12 for pressure regulation. The proportional pressure reducing valve 12 regulates the pressure using a dual-sensor dynamic fusion method to adjust the proportional valve opening control variable. Finally, the flow rate is regulated by the flow control valve 7, ultimately achieving a stable pressure output by the end effector force. In this embodiment, the force sensor and the pressure sensor collect signals and transmit them to the controller, and the control unit transmits corresponding control instructions to the proportional pressure reducing valve.

[0116] The hydraulic end effector force stabilization control system based on dual-sensor dynamic fusion includes a data acquisition device, a controller (also known as a control unit), and an execution unit. Figure 7 , Figure 7 This is a logic block diagram of a dynamic fusion hydraulic end effector force stabilization control system provided in an embodiment of the present application. The data acquisition device includes a sensing unit and a target force setting unit. The sensing unit includes a force sensor and a pressure sensor. The force sensor acquires the force value of the end effector (i.e., the actual output force), and the pressure sensor acquires the pressure value of the system (i.e., the pressure in the pipeline). The target force setting unit is used to input the target force that the end effector needs to output to the controller. The above-mentioned force sensor can be installed on the contact surface between the hydraulic end effector and the load, with a range of 0-5000N and an accuracy of 0.5 The high-precision force sensor is a force sensor with N representing Newton. The accuracy expressed as a percentage in this embodiment is defined based on the full scale (FS). The pressure sensor can be integrated into the oil inlet chamber of the hydraulic cylinder, with a range of 0-10MPa and an accuracy of 0.2 High frequency pressure sensor, MPa stands for megapascals.

[0117] The controller is based on a PLC (Programmable Logic Controller) and uses a dynamic fusion algorithm to calculate the first weight corresponding to the force sensor. , and the second weight corresponding to the pressure sensor The controller can calculate the proportional pressure reducing valve opening control quantity (i.e., the proportional pressure reducing valve adjustment parameter) through a control algorithm and use the proportional pressure reducing valve to accurately control the end force value. The controller can also implement fault detection and switching logic. The above-mentioned controller adopts a PLC-implanted control algorithm, supports the connection of force sensors and pressure sensors, and controls the proportional valve opening through the output module; the controller has a microsecond-level instruction cycle, which can meet the real-time needs of dynamic weight adjustment; the controller can be used to implement complex control strategies such as de-integrated PD algorithm, fault detection logic, and feedforward compensation.

[0118] The actuator unit includes a proportional pressure reducing valve, a hydraulic cylinder, and an end effector. The proportional pressure reducing valve is mainly used as the execution carrier of the control algorithm. It is used to accurately control the output force F of the hydraulic cylinder by adjusting the flow to achieve stable force control of the end effector. The hydraulic cylinder is built into the end effector. The parameters of the proportional pressure reducing valve are as follows: flow rate 0-15L / min, pressure level 3-10MPa, response sensitivity 0.5 , hysteresis loop 5 , repeatability 1 The hydraulic cylinder may be a double-acting hydraulic cylinder with the following parameters: cylinder diameter 63 mm, rod diameter 30 mm, stroke 30 mm, and a built-in displacement sensor with an accuracy of 0.01 mm.

[0119] This embodiment adopts the hydraulic pressure control method to realize the stability of the output force of the end effector by combining the measured value of the force sensor carried by the end effector and the measured value of the pressure sensor output by the proportional pressure reducing valve in a weighted manner. (ie actual output force) and pressure sensor measurement value (i.e., pressure in the pipeline), converted into indirect force ( is the effective area of ​​the end effector hydraulic cylinder), and then set the target force (i.e. the stability force value that needs to be achieved), according to and Error, dynamically adjust the force sensor weight and pressure sensor weights , generating the proportional valve opening control quantity u(t), and switching to pure pressure feedback control mode when a force sensor failure is detected. 、 and u(t) represent the first weight, the second weight, and the proportional valve opening control amount corresponding to time t.

[0120] See Figure 8 , Figure 8 In the dynamic weight adjustment logic flow chart provided in the embodiment of the present application, the controller may perform the following operations:

[0121] Step B1: Obtain real-time data;

[0122] The above real-time data includes target force , force sensor measurement value , pressure sensor measurement value .

[0123] Step B2: Calculate indirect forces;

[0124] Among them, the target force It can be sent by the host computer (such as CNC system), and the controller reads the force sensor measurement value in real time and pressure sensor measurements ;

[0125] Indirect force The calculation formula is: , effective area of ​​hydraulic cylinder , R is the diameter of the hydraulic cylinder, such as 63mm.

[0126] Step B3: Calculate output error;

[0127] Among them, the calculation formula of the output error ec is: .

[0128] Step B4: Determine the range where the output error is located; if the output error is less than or equal to 2 , it means that it is in steady state mode. =0.8, =0.2, give priority to the high-precision characteristics of the force sensor for control; if the output error is greater than 2 and less than 5 , it means that it is in transition mode at this time, which can be determined according to the following formula and : , =1- ; If the output error is greater than or equal to 5 , it means it is in dynamic mode. =0.2, =0.8, giving priority to the use of the fast response characteristics of the pressure sensor for control.

[0129] Step B5: Calculate the residual r; if r>10 Lasts for 5 seconds, then forced =0, =1; otherwise, re-acquire real-time data;

[0130] Among them, the calculation formula of the residual (i.e., system residual) r is .

[0131] Step B6: output weight;

[0132] The method of calculating the weight in step B4 above reflects the dynamic fusion weight algorithm of the controller. The fusion error generation algorithm of the controller is as follows: ; Represents the calculation results of the fusion error production algorithm.

[0133] The controller's de-integrated PD control algorithm is as follows: ;

[0134] above is the adjustment parameter at time t; represents the proportional gain adjusted by the step response method; Indicates the differential gain calculated based on the critical oscillation period.

[0135] The controller's healing logic includes a residual detection algorithm and a degradation control strategy. Figure 9 , Figure 9 This is a fault detection logic diagram provided by the embodiment of the present application. After starting the normal control mode, the sensor data is fused and the residual r is calculated. If r>10 , and it lasts for more than 1 second, it will enter the degraded control mode (at this time =0, =1); if r≤10 , then continue to enter the normal control mode. In the degraded control mode, only the pressure sensor is used to calculate the control parameters until r≤5 And lasts for 2 seconds.

[0136] The residual detection algorithm is: by real-time calculation of the force value deviation between the force sensor and the pressure sensor ; Fault judgment condition: r>10 , and it lasts for more than 1 second, it is determined to be a fault.

[0137] The degradation control strategy is as follows: When a fault is triggered, the =0, =1, only rely on pressure sensor feedback, then adjust the parameters .

[0138] Fault recovery condition is r≤5 Lasts for 2 seconds, then it can automatically switch back to normal mode.

[0139] In the constant force processing scenario of CNC machine tool tools, the above-mentioned hydraulic end-effector force stabilization control solution based on dual-sensor dynamic fusion can be used. In the constant force processing scenario of CNC machine tool tools, the end-effector is the tool, and the specific configuration parameters are as follows:

[0140] Hydraulic cylinder: cylinder diameter 63mm, stroke 50mm.

[0141] Proportional valve: flow rate 0-10L / min.

[0142] Force sensor: range 0-5000N, accuracy 0.5 , installed on the tool holding end.

[0143] The controller is equipped with an analog input module and a PWM (Pulse Width Modulation) output module.

[0144] The pressure regulating device may be a proportional pressure reducing valve.

[0145] If the target force is 3000N, the dynamic weight adjustment process is as follows:

[0146] Steady-state mode: If ≤60N, setting =0.8, =0.2, force sensor dominated control, measured steady-state error ≤30N.

[0147] Dynamic mode: When the tool pressure changes suddenly, the error ≥150N, set =0.2, =0.8, the pressure sensor responds quickly and the adjustment time is 0.1 seconds.

[0148] This embodiment can simulate the failure of the force sensor (signal zero), the residual =3000N, the degradation mode is triggered after 0.5 seconds and switches to pure pressure feedback. The measured error is ≤90N.

[0149] The above pressure regulating device can also be a servo directional valve. Figure 10 , Figure 10 Another hydraulic system schematic diagram provided in an embodiment of the present application includes a hydraulic box 1, a pump 2, a relief valve 3, a gas-liquid booster pump 4, a three-position four-way reversing valve 5, a pressure sensor 6, a flow regulating valve 7, an end effector 8, a force sensor 9, an air tank 10, an air pressure proportional valve 11, and a servo directional valve 13.

[0150] The present application also provides a mechanical device, including a controller, a pressure regulating device, a pressure sensor, an end effector, and a force sensor. The end effector is a fluid-driven actuator. The pressure regulating device is connected to the end effector via a preset pipeline. The pressure regulating device is used to regulate the pressure of the fluid in the preset pipeline. The pressure sensor is disposed in the preset pipeline. The force sensor is disposed on the contact surface between the end effector and the load.

[0151] When the controller is working, the operations performed include:

[0152] Obtaining the actual output force collected by the force sensor;

[0153] Obtaining the pressure in the pipeline collected by the pressure sensor, and calculating the indirect force based on the pressure in the pipeline; wherein the indirect force is the force exerted by the fluid on the end effector;

[0154] Determining an output error based on a difference between the actual output force and the target force, and setting weight information based on the output error; wherein the weight information includes a first weight corresponding to the force sensor and a second weight corresponding to the pressure sensor;

[0155] determining an adjustment parameter based on the weight information, the actual output force, the indirect force, and the target force;

[0156] The pressure regulating device is controlled to operate according to the regulating parameter so that the end effector operates according to the target force.

[0157] The pressure regulating device comprises any one or a combination of any several of a servo directional valve, a proportional pressure reducing valve and a gas-liquid booster pump.

[0158] Since the embodiments of the apparatus part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the apparatus part, and they will not be repeated here.

[0159] This application also provides a storage medium having a computer program stored thereon, which, when executed, can implement the steps provided in the above embodiments. The storage medium may include: a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, among other media capable of storing program code.

[0160] The present application also provides an electronic device that may include a memory and a processor, wherein the memory stores a computer program, and when the processor calls the computer program in the memory, the steps provided in the above embodiment can be implemented. Of course, the electronic device may also include various network interfaces, a power supply, and other components.

[0161] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method section. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of this application.

[0162] It should also be noted that, in this specification, 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 actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. A method for controlling an end effector, characterized in that: A controller for a mechanical device, wherein the control method of the end effector includes: Step 1: Obtain the actual output force collected by the force sensor; obtain the pressure in the pipeline collected by the pressure sensor, and calculate the indirect force based on the pressure in the pipeline; wherein the indirect force is the force exerted by the fluid on the end effector; Step 2: Determine an output error based on the difference between the actual output force and the target force, and set weight information based on the output error; wherein the weight information includes a first weight corresponding to the force sensor and a second weight corresponding to the pressure sensor; Step 3: determining an adjustment parameter based on the weight information, the actual output force, the indirect force, and the target force; Step 4: Controlling the pressure regulating device to operate according to the regulating parameters so that the end effector operates according to the target force; Wherein, determining the adjustment parameter based on the weight information, the actual output force, the indirect force and the target force includes: The difference between the target force and the actual output force is taken as the first error; the difference between the target force and the indirect force is taken as the second error; the first error and the second error are weightedly calculated based on the weight information to obtain a proportional term; the first error is differentiated to obtain a differential term; and the adjustment parameter is determined based on the proportional term and the differential term.

2. The method for controlling the end effector according to claim 1, wherein: Determining an output error according to a difference between the actual output force and the target force, and setting weight information according to the output error, including: setting the absolute value of the difference between the actual output force and the target force as the output error; If the output error is less than or equal to a first threshold, setting the first weight to a first fixed value and setting the second weight to a second fixed value; If the output error is greater than the first threshold and less than a second threshold, setting the first weight and the second weight according to the output error; wherein the first weight is negatively correlated with the output error, and the second weight is positively correlated with the output error; If the output error is greater than a second threshold, the first weight is set to a third fixed value and the second weight is set to a fourth fixed value; wherein the first fixed value is greater than the third fixed value and the second fixed value is less than the fourth fixed value.

3. The method for controlling the end effector according to claim 1, wherein: The calculation formula of the proportional term P is: , Represents the proportional gain, represents the first weight, Indicates the target force, Indicates the actual output force, represents the second weight, Indicates indirect force; The calculation formula of the differential term D is: , represents the differential gain, represents the differential of the first error, and dt represents the differential of time; The adjustment parameters .

4. The method for controlling the end effector according to claim 1, wherein: Before setting weight information according to the output error, the method further includes: The absolute value of the difference between the actual output force and the indirect force is set as the system residual; Determining whether a duration during which the system residual is continuously greater than a third threshold is greater than a first target duration; If so, it is determined that a fault exists, and the end effector control process in the fault mode is started; If not, proceed to the step of setting weight information according to the output error.

5. The method for controlling the end effector according to claim 4, wherein: The end effector control process under the fault mode includes: determining a temporary adjustment parameter according to the actual output force or the indirect force, and controlling the pressure regulating device to operate according to the temporary adjustment parameter; If the duration for which the system residual is continuously less than or equal to the fourth threshold is greater than the second target duration, the step of setting weight information according to the output error is entered; wherein the third threshold is greater than or equal to the fourth threshold.

6. The method for controlling the end effector according to claim 1, wherein: The end effector is an actuator with a built-in hydraulic cylinder; Accordingly, the indirect force is calculated according to the pressure in the pipeline, including: The indirect force is calculated based on the effective area of ​​the hydraulic cylinder and the pressure in the pipeline.

7. A mechanical device, characterized in that: The mechanical device includes a controller, a pressure regulating device, a pressure sensor, an end effector, and a force sensor. The end effector is a fluid-driven actuator. The pressure regulating device is connected to the end effector via a preset pipeline. The pressure regulating device is used to regulate the pressure of the fluid in the preset pipeline. The pressure sensor is disposed in the preset pipeline. The force sensor is disposed on the contact surface between the end effector and the load. When the controller is working, the operations performed include: Step 1: Obtaining the actual output force collected by the force sensor; obtaining the pressure in the pipeline collected by the pressure sensor, and calculating the indirect force based on the pressure in the pipeline; wherein the indirect force is the force exerted by the fluid on the end effector; Step 2: Determine an output error based on the difference between the actual output force and the target force, and set weight information based on the output error; wherein the weight information includes a first weight corresponding to the force sensor and a second weight corresponding to the pressure sensor; Step 3: determining an adjustment parameter based on the weight information, the actual output force, the indirect force, and the target force; Step 4: controlling the pressure regulating device to operate according to the regulating parameters so that the end effector operates according to the target force; Wherein, determining the adjustment parameter based on the weight information, the actual output force, the indirect force and the target force includes: The difference between the target force and the actual output force is taken as the first error; the difference between the target force and the indirect force is taken as the second error; the first error and the second error are weightedly calculated based on the weight information to obtain a proportional term; the first error is differentiated to obtain a differential term; and the adjustment parameter is determined based on the proportional term and the differential term.

8. An electronic device, characterized in that: The device comprises a memory and a processor, wherein a computer program is stored in the memory, and when the processor calls the computer program in the memory, the steps of the end effector control method according to any one of claims 1 to 6 are implemented.

9. A storage medium, characterized in that: The storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the method for controlling the end effector according to any one of claims 1 to 6.

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