Robot compliance control method for electric meter box door operation

Abstract

The invention provides a robot compliance control method for operation of an electric meter box door, relates to the technical field of robot control and intelligent equipment, and particularly aims at typical interaction tasks such as opening of the electric meter box door and the like, and systematic optimization is carried out aiming at the problems of insufficient compliance, poor posture adaptation, weak driving force control and the like in a traditional method. According to the method, speed estimation and a tail end external force / torque feedback mechanism are fused, and through a unified position control framework, the operation stability and the self-adaptive capacity of the robot in a limited space and an unknown door body structure are effectively improved. The application range can cover power facility maintenance scenes such as a distribution room, an electric meter box and a transformer substation auxiliary switch, and the method has good engineering practical value and industrial popularization potential.

Description

Technical Field

[0001] This invention relates to the field of robot control and intelligent equipment technology, and in particular to a compliant robot control method for operating meter box doors. Background Technology

[0002] With the rapid development of smart grids and distribution automation technologies, power inspection robots and maintenance robots are increasingly being used in substations, user distribution rooms, and meter boxes in high-rise residential buildings. Typical tasks include detecting the operating status of electricity meters, reading electricity consumption data, and performing maintenance operations such as opening and closing the boxes. For these tasks, service-type or wheeled-legged hybrid robots need to have the ability to interact with complex structures such as meter boxes in unstructured environments. In particular, when performing "door-opening" operations, the robot needs to complete a series of complex coordinated movements, such as grasping and rotating the door handle and pushing the door, in a confined space.

[0003] However, due to the compact structure, high hinge resistance, inconsistent installation precision, and diverse door materials and conditions (such as rust, looseness, and deformation), robots often face the following challenges in actual operation:

[0004] Limited movement path and narrow space: Electricity meter boxes are often embedded in walls or corners, which limits the freedom of movement of the robotic arm;

[0005] Large environmental perception errors: Traditional vision or position control is difficult to accurately guide the end attitude and thrust direction;

[0006] Therefore, a compliant control method with good compliant control, posture adjustment and path guidance capabilities is needed to improve the robot's practical operation capabilities in power application scenarios. Summary of the Invention

[0007] This invention aims to address the problems of insufficient driving force, unstable compliant direction estimation, and inadequate posture adjustment in robot operation tasks involving meter box doors. It proposes a compliant control method that combines speed estimation and external force / torque sensing mechanisms to improve the stability and adaptability of robot interactive operations in typical task scenarios such as power distribution inspection and power maintenance.

[0008] This method is particularly suitable for robots in the context of compact meter boxes with unpredictable door conditions, enabling them to efficiently open the box doors and complete subsequent task preparations.

[0009] To achieve the above objectives, this invention provides a compliant end-effector control method for service robots. Its core lies in integrating four types of position commands to construct a unified position control framework, specifically including:

[0010] Initial position command: Defines the robot's reference starting pose before performing the interactive task;

[0011] Velocity-based position increment planning: Through a two-stage velocity planning strategy, the robot end effector is guided to actively drive the gate in the initial stage, and the current minimum resistance direction is estimated based on the end effector velocity in the guidance stage, thereby planning the end effector motion direction;

[0012] Force-based compliant displacement control: A second-order force compliant controller with no stiffness term is adopted to generate a compliant translational response based on the measured end force, thereby achieving force-controlled adjustment;

[0013] Position adaptation adjustment based on external torque: When the robot is subjected to external torque, it automatically adjusts the end effector posture to adapt to the angle change of the door handle, while keeping the spatial position of the gripping point unchanged. This part is the main innovation of the patent.

[0014] The method also incorporates velocity signal filtering and two-dimensional plane constraint processing to improve the stability of the minimum drag direction estimation; during attitude adjustment, the clamping point position is kept stable through rotation matrix transformation, effectively reducing spatial disturbances caused by attitude adjustment.

[0015] Preferably, the overall control command is based on the initial position and superimposed with three types of compliant increments, as shown in the following expression:

[0016] P ref =P init +△P V +△P F +△P M

[0017] Where: P init Let △P be the robot's initial position. V For the planned location increment based on velocity estimation, △P F For compliant translation driven by external force, ΔP M This refers to compliant translation driven by an external torque.

[0018] Preferably, the planned location increment based on velocity estimation can be expressed as:

[0019] △P V =∫ B V set dt

[0020] In the initial stage B V set =V init .

[0021] Preferably, during the guidance phase B V set =V set d. Among them, B Vset This represents the planned speed of the robotic arm's end effector, defined in the base coordinate system. Its setting is divided into two stages to achieve effective driving and compliant adjustment of the door:

[0022] Initial Phase 1: The robotic arm operates at an initial speed V set by the user. init To begin movement, the direction of the initial velocity should be at an angle of less than 90° to the normal direction of the door, in order to ensure that an effective driving force can be applied to the door in the initial stage, causing it to rotate about the hinge direction.

[0023] Guidance phase: When the system detects that the end velocity has reached the preset threshold, it enters the guidance phase. At this time, the system will estimate the direction of minimum resistance d based on the instantaneous velocity of the gripper, that is, the direction of minimum environmental reaction force under the current contact state.

[0024] Preferably, the robotic arm control system needs to obtain the speed information of the end effector. B V T To calculate the translational velocity of the end gripping point. B V G Its expression is as follows:

[0025] B V G = B V T +ω×( B R T t peg )

[0026] in, B V T ω and t represent the linear velocity and angular velocity of the robotic arm's end effector in the base coordinate system, respectively; peg =[0,0,L] is the offset vector of the end gripping point relative to the origin of the end coordinate system, where L represents the offset distance, and the minimum drag direction d is defined as... B V G Unit vectors with the same direction.

[0027] A computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the robot compliant control method for operating an electricity meter box door as described above.

[0028] A processor for running a program, wherein the program, when running, executes the robot compliant control method for operating an electricity meter box door as described above.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] Highly compliant: Employing real-time velocity estimation and force sensing mechanisms, combined with a compliant controller, enhances the robot's ability to adapt to changes in the contact environment.

[0031] In summary, the control method proposed in this invention can be widely applied to the interactive control systems of service robots, medical robots, or industrial collaborative robots in complex environmental tasks, and has significant application value and promising prospects for promotion. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0033] Figure 1 The direction and reference coordinate system of Vinit;

[0034] Figure 2 The result of the posture adjustment before the improvement;

[0035] Figure 3 This refers to the position adjustment process under translational compliance control based on external torque. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0038] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0040] This invention addresses the control challenges faced by service robots in unstructured constraint environments when performing door handle-like interactive tasks. It proposes an compliant control method based on velocity estimation and force / torque feedback to achieve efficient and safe interaction of the robotic arm's end effector within a door structure. This method integrates position command decomposition, velocity-guided control, force-based compliant adjustment, and attitude adaptation mechanisms to construct an adaptive operation framework for unknown constraint environments.

[0041] During system operation, the overall control command is based on the initial position and superimposed with three types of compliant increments, as shown in the following expression:

[0042] P ref =P init +△P V +△P F +△P M (1)

[0043] Where: P init Let △P be the robot's initial position. V For the planned location increment based on velocity estimation, △P F For compliant translation driven by external force, ΔP M This is a compliant translation driven by an external torque. This strategy employs admittance control, so P... ref It's position control.

[0044] This control method supports triggering the door movement at a set speed in the initial stage, and then gradually transitioning to a compliant adjustment dominated by environmental feedback, so as to ensure safe and stable operation in complex and unconstrained scenarios.

[0045] Translational adaptation planning based on velocity estimation

[0046] The planned location increment based on velocity estimation can be expressed as:

[0047] △P V =∫ B V set dt (2)

[0048] In the initial stage B V set =V init During the guidance phase B V set =V set d. Among them, B Vset This represents the planned speed of the robotic arm's end effector, defined in the base coordinate system. Its setting is divided into two stages to achieve effective driving and compliant adjustment of the door:

[0049] Initial Phase 1: The robotic arm operates at an initial speed V set by the user. init Begin movement. The direction of this initial velocity should form an angle of less than 90° with the normal direction of the door to ensure that an effective driving force can be applied to the door in the initial stage, causing it to rotate about the hinge direction (as shown in the attached diagram). Figure 1 (As shown).

[0050] Guiding Phase: Once the system detects that the end-effector velocity has reached a preset threshold, it enters the guiding phase. At this time, the system estimates the direction of minimum resistance d based on the instantaneous velocity of the gripper, which is the direction of minimum environmental reaction force under the current contact state, in order to facilitate stable door movement.

[0051] The following section will introduce the method for calculating the direction of minimum resistance, d. First, the robotic arm control system needs to obtain the speed information of the end effector. B V T To calculate the translational velocity of the end clamping point. B V G Its expression is as follows:

[0052] B V G = B V T +ω×( B R T t peg (3)

[0053] in, B V T ω and t represent the linear velocity and angular velocity of the robotic arm's end effector in the base coordinate system, respectively; peg =[0,0,L] represents the end gripping point relative to the origin of the end coordinate system. offset vector L represents the offset distance. The direction of minimum resistance d is defined as... B V G Unit vectors with the same direction. B R T Let be the rotation matrix from the base coordinate system to the end coordinate system.

[0054] Adaptive Displacement Control Based on External Forces

[0055] To achieve a compliant response at the end of the robotic arm during the contact process, a second-order force compliance controller without stiffness term is used to generate a translational compliant displacement of the end gripping point under the action of external force.

[0056] Adaptive displacement ΔP FSatisfy the following equation:

[0057] M p d 2 (△P F ) / dt 2 +B p d(△P F ) / dt=F (4)

[0058] Where F represents the end force measured in the base coordinate system, and M... p and B p These are symmetric positive definite virtual mass and damping matrices, used to adjust the system's inertial response and velocity damping to external forces.

[0059] Translational compliance control based on external torque

[0060] To improve the system's compliance during contact operations, a translational compliance control strategy based on external torque was introduced. This strategy, through the design of a torque-compliant controller, enables the robot to adjust its posture around the gripping point when subjected to the torque of the door handle. This effectively addresses changes in the door handle's angle while maintaining the spatial position of the gripping point, effectively reducing positional disturbances caused by posture adjustments. (See attached diagram.) Figure 2 As shown.

[0061] In this control scheme, attitude adjustment is performed in increments of rotational angle Δθ around the y-axis. y The dynamic response to this attitude increment is given by the following second-order differential equation:

[0062] M R d 2 (△θ y ) / dt 2 +B R d(△θ y ) / dt=τ (5)

[0063] Among them, M R and B R Let be the virtual moment of inertia and the rotational damping coefficient, respectively, and τ be the component of the external torque acting on the end about the y-axis, where the y-axis is aligned with the hinge direction of the door. ΔP can be obtained from Δθy. M have to:

[0064] △P M =R init (t peg -R y (△θ y )t peg (6)

[0065] R init为 The initial rotation matrix ΔP at the start of the motion of the robotic arm's end effector.M This allows the robot to rotate around the gripping point as the center of rotation when adjusting its posture, avoiding the generation of excessive forces during posture adjustment. This is the core part of this patent, R. y (△θ y ) is a rotation matrix around the y-axis.

[0066] robot posture commands

[0067] The robot's posture commands are achieved by adjusting the posture matrix at the end effector of the robotic arm. The set reference posture matrix R... ref for:

[0068] R ref =R init R y (△θ y (7)

[0069] Among them, R init为 The initial rotation matrix R of the robotic arm's end effector at the start of motion. y (△θ y ) is a rotation matrix around the y-axis, used to correct the gripper's orientation. △θ y It is calculated by a translational compliance control algorithm based on external torque. It can also be expressed as: Δθ y It is calculated by a torque-based compliant control algorithm.

[0070] Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0071] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical functional division. In actual implementation, there may be other division methods, such as multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored.

[0072] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0073] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A compliant control method for a robot used in operating an electricity meter box door, characterized in that, Includes the following steps: The robot's control commands consist of an initial position, a planned position increment estimated based on velocity, an adaptive translation increment generated by external force, and an adaptive translation increment generated by external torque, all superimposed. Initial position: The robot's reference starting pose before performing the interactive task; Velocity-based position increment planning: Through a two-stage velocity planning strategy, the robot end effector is guided to actively drive the gate in the initial stage, and the current minimum resistance direction is estimated based on the end effector velocity in the guidance stage, thereby planning the end effector motion direction; Compliant translational increments driven by external forces: A second-order force compliant controller with no stiffness term is adopted to generate a compliant translational response based on the measured end external force, thereby achieving force-controlled adjustment; Adaptive translational increments driven by external torque enable the robot to automatically adjust its end effector posture when subjected to external torque to adapt to changes in the door handle angle, while maintaining the spatial position of the gripping point.

2. The robot compliant control method for operating an electricity meter box door according to claim 1, characterized in that, Velocity signal filtering and two-dimensional plane constraint processing are introduced to improve the stability of minimum drag direction estimation. During attitude adjustment, the position of the clamping point is kept stable by rotation matrix transformation, which effectively reduces spatial disturbances caused by attitude adjustment.

3. The robot compliant control method for operating an electricity meter box door according to claim 1, characterized in that, The overall control command is based on the initial position and consists of three types of compliant increments, expressed as follows: P ref =P init +△P V +△P F +△P M Where: P init Let △P be the robot's initial position. V For the planned location increment based on velocity estimation, △P F For compliant translation driven by external force, ΔP M This refers to compliant translation driven by an external torque.

4. The robot compliant control method for operating an electricity meter box door according to claim 3, characterized in that, The planned location increment based on velocity estimation can be expressed as ΔP. V =∫ B V set dt In the initial stage B V set =V init B indicates that the variable is represented in the base system {B}, V init This represents the initial velocity.

5. A robot compliant control method for operating an electricity meter box door according to claim 4, characterized in that, During the guidance phase B V set =V set d. Among them, B V set This represents the planned velocity of the robotic arm's end effector, defined in the base coordinate system. Its setting is divided into two stages to achieve effective driving and compliant adjustment of the door. d represents the direction of minimum resistance. Initial Phase 1: The robotic arm operates at an initial speed V set by the user. init To begin movement, the direction of the initial velocity should be at an angle of less than 90° to the normal direction of the door, in order to ensure that an effective driving force can be applied to the door in the initial stage, causing it to rotate about the hinge direction. Guidance phase: When the system detects that the end velocity has reached the preset threshold, it enters the guidance phase. At this time, the system will estimate the direction of minimum resistance d based on the instantaneous velocity of the gripper, that is, the direction of minimum environmental reaction force under the current contact state.

6. A robot compliant control method for operating an electricity meter box door according to claim 5, characterized in that, The robotic arm control system needs to obtain the speed information of the end effector. B V T To calculate the translational velocity of the end clamping point. B V G Its expression is as follows: B V G = B V T +ω×( B R T t peg ) in, B V T ω and t represent the linear velocity and angular velocity of the robotic arm's end effector in the base coordinate system, respectively; peg =[0,0,L] is the offset vector of the end gripping point relative to the origin of the end coordinate system, where L represents the offset distance, and the minimum drag direction d is defined as... B V G Unit vectors with the same direction B R T Let be the rotation matrix from the base coordinate system to the end coordinate system.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the robot compliant control method for operating an electricity meter box door as described in any one of claims 1 to 6.

8. A processor, characterized in that, The processor is used to run a program, wherein the program executes the robot compliant control method for operating the meter box door as described in any one of claims 1 to 6.

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