A human-computer interaction safety control method based on speed mapping

Abstract

The present invention relates to a human-machine interaction safety control method based on a speed mapping band, comprising the following steps: within an axial working area, using a manipulator admittance control method to implement human-machine interactive dragging teaching of the manipulator; determining the robot's safe working range based on the human-machine interaction range and the manipulator's workspace, and setting position-based limits at the edge of the safe working range; setting a speed mapping band within the safe working range for performing speed mapping when the robot approaches the limit point; calculating a speed curve within the speed mapping band based on a target speed change curve as a speed threshold; within the speed mapping band, controlling the manipulator based on the speed threshold and the control speed generated by the admittance control method; and within other workspaces outside the speed mapping band, controlling the manipulator based on the control speed generated by the admittance control method. Compared with existing technologies, the present invention has the advantages of ensuring safety and improving user experience.

Description

Technical Field

[0001] The present invention relates to the technical field of robot admittance control, and in particular to a human-machine interaction safety control method based on a speed mapping belt. Background Art

[0002] With the rapid development of modern industrial automation and intelligent manufacturing, robots are playing an increasingly important role in production processes. Advances in robotics not only improve production efficiency but also place higher demands on operational flexibility and safety. As one of the key technologies to achieve this, the development of human-machine interaction (HMI) has garnered widespread attention.

[0003] Among existing human-machine interaction technologies, teaching by demonstration is a common method that allows an operator to teach a robot to perform specific tasks by directly guiding it. However, traditional teaching by demonstration methods have some limitations. When the robot approaches the position limit at the edge of the workspace, traditional position limit methods often cause sudden changes in speed. This sudden change not only impacts the robot's mechanical structure but can also pose a safety hazard to the operator, resulting in a poor human-machine interaction experience. Summary of the Invention

[0004] The purpose of the present invention is to provide a human-machine interaction safety control method based on speed mapping belt. By introducing the concept of speed mapping belt, a specific speed control area is set at the edge of the robot's workspace for speed mapping, so that the robot can achieve smooth speed adjustment when approaching the edge, thereby improving the safety of operation and the naturalness of interaction.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A human-machine interaction safety control method based on a speed mapping tape comprises the following steps:

[0007] Step 1) In the axial working area, a manipulator admittance control method is used to realize human-machine interactive drag teaching of the manipulator;

[0008] Step 2) Determine the robot's safe operating range based on the human-machine interaction range and the robot's workspace. Set position-based limits at the edge of the safe operating range to ensure that the robot cannot move outside the workspace.

[0009] Step 3) Setting a speed mapping zone within the working safety zone. The speed mapping zone is a rectangular area within a preset range from the limit point, which is used for speed mapping when the robot approaches the limit point;

[0010] Step 4) calculating a speed curve within the speed mapping band according to the target speed change curve as a speed threshold;

[0011] Step 5) Within the speed mapping band, the manipulator is controlled based on the speed threshold and the control speed generated by the admittance control method. In other workspaces except the speed mapping band, the manipulator is controlled based on the control speed generated by the admittance control method.

[0012] The step 1) comprises the following steps:

[0013] Step 1-1) Construct a dynamic model of the contact between the human arm and the end of the robotic arm in one dimension f e =α e (x e -x c ), the traditional admittance control equation is expressed as:

[0014]

[0015] Among them, x e and x c are the environment position on a single degree of freedom and the actual position of the end of the manipulator, k e is the stiffness of the human arm; position deviation e = x d -x e , where x d Indicates the desired contact position; and are the first-order derivative and second-order derivative of the position deviation, m is the mass coefficient of the robot arm, b is the damping coefficient of the robot arm, k is the stiffness coefficient of the robot arm, and f e 、f d are the contact force and expected force at the end of the robot arm, respectively, and Δf is the deviation between the two;

[0016] Step 1-2) Construct the transfer function of position error

[0017]

[0018] Where s is the signal input of the transfer function;

[0019] Step 1-3) When the system is in steady state, that is, when s tends to 0, the steady-state tracking force error Δf ss for:

[0020]

[0021] Steps 1-4) In order to make the tracking force error of the system steady-state error zero, one of the following conditions must be met: i) the stiffness of the admittance controller is 0; ii) the reference position x r for:

[0022]

[0023] Steps 1-5) Set the admittance controller parameters of each axis to 0 to implement the robot arm drag teaching.

[0024] The traditional admittance control equation is:

[0025]

[0026] Among them, F ext Indicates the actual applied force, F d represents the desired contact force, X c , represents the actual position, velocity and acceleration of the end effector of the robot arm, X d , represents the desired position, velocity, and acceleration of the end effector, M d , D d and K d They correspond to the required virtual mass matrix, damping matrix and stiffness matrix respectively.

[0027] In step 2), the method for implementing position-based limiting is:

[0028]

[0029] Among them, v r is the movement speed; v c is the control speed calculated by the admittance control method, orientation x max The control speed of the movement in the direction is positive, and the speed in the direction of x min The control speed of the direction of movement is negative; x min 、x max It is the speed band limit position.

[0030] The limit position x min and x max The absolute value of is less than or equal to the absolute value of the boundary value of the working safety interval.

[0031] The method for determining the starting point of the speed mapping band is as follows: the starting point of the speed mapping band is calculated according to the limit position obtained in step 2):

[0032] x bmin =x min +τ*x all

[0033] x bmax =x max -τ*x all

[0034] Among them, x bmin 、xbmax Respectively represent the speed limit position x in the axial working area min 、x max The starting point of the corresponding velocity mapping band, τ is the mapping band width coefficient, x all is the total length of the axial working area.

[0035] The mapping band width coefficient is determined according to the size of the working safety interval and the mapping effect to be achieved.

[0036] The calculation method of the speed threshold in step 4) is:

[0037] Step 4-1) Calculate the position-velocity mapping function during uniform deceleration:

[0038]

[0039] Step 4-2) Set the speed limit position x according to step 2) max and x min , calculate the speed threshold v:

[0040] Will and Substitute the corresponding formulas of the position-speed mapping function to obtain the speed threshold:

[0041]

[0042] Here, ε is a constant related to the acceleration a.

[0043] Set the initial velocity threshold v m , ensure that the maximum end speed of the robot entering the speed mapping zone does not exceed this value, and set the speed mapping zone boundary x bmax 、x bmin Substitute them into the speed threshold formula in step 4-2) to obtain:

[0044]

[0045] The step 5) is specifically as follows: after the robot enters the speed mapping band, the control speed v generated by the speed threshold v in the speed mapping band and the impedance control is c , adjust the robot's movement speed v in real time r ,in,

[0046]

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The present invention introduces the concept of speed mapping band to achieve speed mapping near the limit point, avoiding the speed mutation problem caused by the traditional position limit method and improving the safety and flexibility of human-computer interaction.

[0049] (2) The present invention adopts the position-speed mapping function of the uniform deceleration process as the speed threshold, which ensures that the robot can decelerate uniformly within the speed mapping band, further improving the human-computer interaction experience.

[0050] (3) An initial speed threshold is set. The present invention ensures that the maximum terminal speed of the robot entering the speed mapping band does not exceed this value, thereby effectively preventing the occurrence of speed mutations. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a flow chart of the method of the present invention;

[0052] Figure 2 It is a schematic diagram of the drag teaching process and the determined speed mapping band;

[0053] Figure 3 Schematic diagram of the speed control method with speed mapping. DETAILED DESCRIPTION

[0054] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0055] like Figure 1 As shown, this embodiment provides a human-computer interaction safety control method based on speed mapping, comprising the following steps:

[0056] Step 1) Figure 2 As shown in the figure, in the axial working area, the manipulator admittance control method is used to realize the manipulator human-machine interactive drag teaching.

[0057] Step 1) includes the following steps:

[0058] Step 1-1) Construct the traditional admittance control equation:

[0059]

[0060] Among them, F ext Indicates the actual applied force, F d represents the desired contact force, X c , represents the actual position, velocity and acceleration of the end effector of the robot arm, X d , represents the desired position, velocity, and acceleration of the end effector, Md , D d and K d They correspond to the required virtual mass matrix, damping matrix and stiffness matrix respectively.

[0061] Construct a dynamic model of the contact between the human arm and the end of the robotic arm in one dimension f e =k e (x e -x c ), the traditional admittance control equation is expressed as:

[0062]

[0063] Among them, x e and x c are the environment position on a single degree of freedom and the actual position of the end of the manipulator, k e is the stiffness of the human arm; position deviation e = x d -x e , where x d Indicates the desired contact position; and are the first-order derivative and second-order derivative of the position deviation, m is the mass coefficient of the robot arm, b is the damping coefficient of the robot arm, k is the stiffness coefficient of the robot arm, and f e 、f d are the contact force and expected force at the end of the robot arm, respectively, and Δf is the deviation between the two.

[0064] Steps 1-2) Construct the transfer function of position error:

[0065]

[0066] Where s is the signal input of the transfer function;

[0067] Step 1-3) When the system is in steady state, that is, when s tends to 0, the steady-state tracking force error Δf ss for:

[0068]

[0069] Steps 1-4) In order to make the tracking force error of the system steady-state error zero, one of the following conditions must be met: i) the stiffness of the admittance controller is 0; ii) the reference position x r for:

[0070]

[0071] Steps 1-5) Set the admittance controller parameters of each axis to 0 to implement the robot arm drag teaching.

[0072] Start the robotic arm control system, put the arm into position control mode, and load the programmed admittance control algorithm. Based on the physical parameters of the robotic arm, configure the damping and mass coefficients to ensure the arm is stable.

[0073] Step 2) Determine the robot's safe working range based on the human-machine interaction range and the robot's workspace. Set position-based limits at the edge of the safe working range to ensure that the robot cannot move outside the workspace.

[0074] Determine the range of motion of the manipulator during human-machine interaction and the working range of the manipulator itself, and take the minimum of the two as the position limit of the manipulator. max The speed of the direction movement is positive. When it is outside the boundary of the position limit, it can only move inside the boundary. The implementation method of the position limit is:

[0075]

[0076] Among them, v r is the movement speed; v c is the control speed calculated by the admittance control method, orientation x max The control speed of the movement in the direction is positive, and the speed in the direction of x min The control speed of the direction of movement is negative; x min 、x max is the speed limit position. That is, according to the determined position limit x min 、x max When the position limit is exceeded, the movement speed of the robot arm is set to 0 so that it cannot move to a position outside the range.

[0077] In this embodiment, the limit position x min and x max The absolute value of is less than or equal to the absolute value of the boundary value of the working safety interval. In a preferred embodiment, the limit position value is slightly smaller than the boundary value of the working safety interval, leaving a certain margin to ensure working safety while not affecting the normal operation of the robot arm.

[0078] Step 3) Set a speed mapping zone within the working safety range. The speed mapping zone is a rectangular area within a preset range of the limit point, such as Figure 2 As shown, it is used to perform velocity mapping when the robot approaches the limit point.

[0079] Calculate the starting point of the speed mapping band based on the limit position obtained in step 2):

[0080] x bmin =x min +τ*x all

[0081] xbmax =x max -τ*x all

[0082] Among them, x bmin 、x bmax Respectively represent the speed limit position x in the axial working area min 、x max The starting point of the corresponding velocity mapping band, τ is the mapping band width coefficient, x all is the total length of the axial working area.

[0083] The mapping band width coefficient τ is determined according to the size of the working safety range and the mapping effect to be achieved. In this embodiment, τ is set to 0.1 to ensure that the normal working area is not affected and a smooth deceleration effect is achieved.

[0084] Step 4) Calculate the speed curve within the speed mapping band according to the target speed change curve as the speed threshold.

[0085] Step 4-1) Calculate the position-velocity mapping function

[0086] In this embodiment, the max Taking the scenario of moving in the direction and arriving at the speed mapping band as an example, the speed curve within the speed mapping band is deduced:

[0087] Determine the speed change relationship:

[0088] v=v0-at

[0089] The position change function is obtained by integration:

[0090]

[0091] The relationship between speed and position is derived based on the speed change relationship and position change function:

[0092]

[0093]

[0094] To x min The calculation process in the scenario of moving in the direction and arriving at the speed mapping band is similar to the above process. Those skilled in the art know how to derive it, so this embodiment will not be described in detail here. The position-speed mapping function is thus obtained as follows:

[0095]

[0096] Step 4-2) Set the speed limit position x according to step 2) max and x min , calculate the speed threshold v:

[0097] Will and Substitute the corresponding formulas of the position-speed mapping function to obtain the speed threshold:

[0098]

[0099] Here, ε is a constant related to the acceleration a.

[0100] In this embodiment, the initial speed threshold v is set m , to ensure that the maximum end speed of the robot entering the speed mapping zone does not exceed this value, thereby avoiding speed mutations and improving the human-machine interaction experience. bmax 、x bmin Substitute them into the speed threshold formula in step 4-2) to obtain:

[0101]

[0102] In this embodiment, v m =0.5m / s. Under normal drag teaching, the speed of the robot end generally does not exceed this value. Based on τ=0.1, the ε value can be set to:

[0103]

[0104] Step 5) Within the speed mapping band, the manipulator is controlled based on the speed threshold and the control speed generated by the admittance control method. In other workspaces except the speed mapping band, the manipulator is controlled based on the control speed generated by the admittance control method.

[0105] Specifically: Figure 3 As shown, after the robot enters the speed mapping band, the control speed v generated by the speed threshold v in the speed mapping band and the impedance control c , adjust the robot's movement speed v in real time r ,in,

[0106]

[0107] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A human-computer interaction safety control method based on speed mapping, characterized in that: The following steps are involved: Step 1) In the axial working area, the manipulator admittance control method is used to realize the manipulator human-machine interactive drag teaching; Step 2) Determine the robot's safe operating range based on the human-machine interaction range and the robot's workspace. Set position-based limits at the edge of the safe operating range to ensure the robot cannot move outside the workspace. Step 3) Set a speed mapping zone within the safe working range. The speed mapping zone is a rectangular area within a preset range from the limit point, used for speed mapping when the robot approaches the limit point. The starting point of the speed mapping zone is determined by calculating the starting point of the speed mapping zone based on the limit position obtained in step 2): in, 、 Respectively represent the speed map with limit position in the axial working area 、 The starting point of the corresponding velocity mapping band, is the mapping bandwidth coefficient, is the total length of the axial working area; Step 4) Calculate the speed curve within the speed mapping band according to the target speed change curve as the speed threshold; orientation The control speed of the movement in the positive direction is The control speed of the direction movement is negative, and the calculation method of the speed threshold is: Step 4-1) Calculate the position-velocity mapping function during uniform deceleration: Step 4-2) Set the speed map with limit position according to step 2) and , calculate the speed threshold : Will , and , Substitute the corresponding formulas of the position-speed mapping function to obtain the speed threshold: Where ε is a constant and is related to the acceleration a Related; Set the initial speed threshold , ensure that the maximum end speed of the robot entering the speed mapping zone does not exceed the initial speed threshold, and move the speed mapping zone starting point 、 Substitute them into the speed threshold formula in step 4-2) to obtain: Step 5) Within the speed mapping band, the manipulator is controlled based on the speed threshold and the control speed generated by the admittance control method. In other workspaces except the speed mapping band, the manipulator is controlled based on the control speed generated by the admittance control method.

2. The human-computer interaction safety control method based on speed mapping according to claim 1 is characterized in that: The step 1) includes the following steps: Step 1-1) Build a dynamic model of the contact between the human arm and the end of the robotic arm in one dimension , the traditional admittance control equation is expressed as: in, and are the environmental position on a single degree of freedom and the actual position of the end of the robotic arm, The stiffness of the human arm; position deviation ,in Indicates the desired contact position; and are the first and second derivatives of the position deviation, m is the mass coefficient of the robotic arm, b is the damping coefficient of the manipulator, k is the stiffness coefficient of the robot arm, 、 are the contact force and expected force at the end of the robot arm, is the deviation between the two; Step 1-2) Construct the transfer function of position error in, is the signal input of the transfer function; Steps 1-3) When the system is in steady state, that is s When it approaches 0, the steady-state tracking force error for: Steps 1-4) In order for the system's steady-state tracking force error to be zero, one of the following conditions must be met: i) the stiffness of the admittance controller is zero; ii) the reference position for: Steps 1-5) Set the admittance controller parameters for each axis to 0 to implement drag teaching of the robot arm.

3. The human-computer interaction safety control method based on speed mapping band according to claim 2 is characterized in that: The traditional admittance control equation is: in, represents the actual applied force, represents the desired contact force, , , Represents the actual position, velocity and acceleration of the end effector of the robot arm, , , represents the desired position, velocity, and acceleration of the end effector, , and They correspond to the required virtual mass matrix, damping matrix and stiffness matrix respectively.

4. The human-computer interaction safety control method based on speed mapping according to claim 1 is characterized in that: In step 2), the method for implementing position-based limiting is: in, is the movement speed; The control speed calculated by the admittance control method.

5. The human-computer interaction safety control method based on speed mapping tape according to claim 4 is characterized in that: The limit position and The absolute value of is less than or equal to the absolute value of the boundary value of the working safety interval.

6. The human-computer interaction safety control method based on speed mapping band according to claim 1 is characterized in that: The mapping band width coefficient is determined according to the size of the working safety interval and the mapping effect to be achieved.

7. The human-computer interaction safety control method based on speed mapping band according to claim 1 is characterized in that: The step 5) is specifically as follows: after the robot enters the speed mapping band, according to the speed threshold in the speed mapping band and the control speed generated by admittance control , adjust the robot's movement speed in real time ,in, 。

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