CN-116175645-B - Determination method for external force applied to mechanical arm, mechanical arm and storage medium

CN116175645BCN 116175645 BCN116175645 BCN 116175645BCN-116175645-B

Abstract

The application discloses a method for determining external force applied to a mechanical arm, which comprises a plurality of connecting rods and a plurality of joints, wherein six-degree-of-freedom force and moment sensors are arranged in the joints at two ends of at least part of the connecting rods and are used for sensing forces and moments acting on the corresponding joints. The method comprises the steps of obtaining inertial attribute parameters of each connecting rod, determining motion state parameters of each connecting rod, determining inertial force and inertial moment of a target connecting rod at the center of mass according to the motion state parameters and the inertial attribute parameters, obtaining force and moment between two ends of the target connecting rod and corresponding joints through the force and moment sensors, and determining external force born by the target connecting rod according to the inertial force and inertial moment of the target connecting rod at the center of mass and the force and moment between two ends of the target connecting rod and the corresponding joints. The application also provides a mechanical arm and a storage medium. The application can accurately detect the external force born by each connecting rod of the mechanical arm.

Inventors

Guan Jitao
LI SHUHAN
JIANG HAO

Assignees

上海非夕机器人科技有限公司
非夕科技有限公司

Dates

Publication Date: 20260505
Application Date: 20230220

Claims (10)

1. The method for determining the external force applied to the mechanical arm is characterized in that the mechanical arm comprises a plurality of connecting rods and a plurality of joints which are sequentially connected, the connecting rods are connected through the joints, six-degree-of-freedom force and moment sensors are arranged in the joints at the two ends of at least part of the connecting rods, and the six-degree-of-freedom force and moment sensors are used for sensing the force and moment acting on the corresponding joints, and the method comprises the following steps: acquiring inertia attribute parameters of each connecting rod, wherein the inertia attribute parameters comprise mass, mass center and rotational inertia of the connecting rod; determining a motion state parameter of each connecting rod, wherein the motion state parameter comprises an angular speed, an angular acceleration and a linear acceleration of each connecting rod; Determining the inertia force and the inertia moment of the target connecting rod at the centroid according to the motion state parameter and the inertia attribute parameter of each connecting rod; acquiring the force and the moment between the two ends of the target connecting rod and the corresponding joints through the six-degree-of-freedom force and moment sensor and And determining the external force born by the target connecting rod according to the inertia force and the inertia moment of the target connecting rod at the mass center and the force and the moment between the two ends of the target connecting rod and the corresponding joints.
2. The method of claim 1, wherein said determining a motion state parameter for each of said connecting rods comprises: Acquiring connection parameters of each joint and angle information of each joint, wherein the connection parameters are parameters representing spatial position relations of two adjacent connecting rods, and the angle information of each joint comprises joint angular position, joint angular speed and joint angular acceleration And determining the motion state parameter of each connecting rod according to the principle of robot dynamics according to the inertia attribute parameter of each connecting rod, the connection parameter of each joint and the angle information of each joint.
3. The method according to claim 1, wherein each connecting rod is provided with an inertial measurement unit for measuring angular velocity, angular acceleration and linear acceleration of the corresponding connecting rod, and wherein determining the motion parameter of each connecting rod comprises: And acquiring the motion state parameters of each connecting rod from the inertial measurement unit.
4. The method of claim 1, wherein determining the inertial force and moment of inertia of the target connecting rod at the centroid based on the motion state parameter and the inertial property parameter of each connecting rod comprises: And determining the inertia force and the inertia moment of the target connecting rod at the centroid by utilizing a reverse recurrence equation in an iterative Newton-Euler equation according to the motion state parameter and the inertia attribute parameter of each connecting rod.
5. The method of claim 4, wherein determining the external force to which the target connecting rod is subjected based on the inertial force and moment of inertia of the target connecting rod at the centroid and the force and moment between the two ends of the target connecting rod and the corresponding joints comprises: And determining a first difference value between the inertial force of the target connecting rod at the centroid and the force between the two ends of the target connecting rod and the corresponding joints, and determining the first difference value as the magnitude and the direction of the external force applied to the target connecting rod.
6. The method of claim 5, wherein the method further comprises: Determining a net moment at a reference point of the target connecting rod based on a second difference between the moment between the two ends of the target connecting rod and the corresponding joints and the moment of inertia of the target connecting rod at the centroid, and And determining the position of the external force born by the target connecting rod relative to the reference point according to the net moment at the reference point of the target connecting rod and the magnitude and direction of the external force born by the target connecting rod.
7. The method of claim 6, wherein prior to determining the location of the external force experienced by the target connecting rod relative to the reference point based on the net moment at the reference point of the target connecting rod and the magnitude and direction of the external force experienced by the target connecting rod, the method further comprises: determining whether the magnitude of the external force is greater than a preset first threshold value, and determining whether the value of the net moment is greater than a preset second threshold value; if the magnitude of the external force is smaller than the first threshold value, determining that the target connecting rod is not subjected to the external force, and And if the magnitude of the external force is greater than or equal to the first threshold value and the value of the net moment is smaller than the second threshold value, determining that the external force born by the target connecting rod is positioned at the reference point.
8. The method of claim 7, wherein if the magnitude of the external force is greater than or equal to the first threshold value and the value of the net moment is greater than the second threshold value, determining the position of the external force applied to the target connecting rod relative to the reference point according to the following formula: Wherein r mag is the shortest distance from the reference point to the line of action of external force exerted on the target connecting rod, r vec is the shortest vector from the reference point to the line of action of external force exerted on the target connecting rod, M is the net moment, and F is the magnitude and direction of the external force exerted on the target connecting rod.
9. A robotic arm, comprising: A plurality of connecting rods connected in sequence; the connecting rods are connected through the joints; A plurality of six-degree-of-freedom force and moment sensors provided in the joints at both ends of at least part of the connecting rod, the six-degree-of-freedom force and moment sensors for sensing forces and moments acting on the corresponding joints, and At least one memory and at least one processor, the at least one memory having stored therein computer program instructions that, when executed by the at least one processor, perform the method of determining an external force experienced by a robotic arm as claimed in any one of claims 1-8.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements a method for determining an external force applied to a robot arm according to any of claims 1-8.

Description

Determination method for external force applied to mechanical arm, mechanical arm and storage medium Technical Field The application relates to the field of robots, in particular to a method for determining external force applied to a mechanical arm, the mechanical arm and a storage medium. Background At present, the mechanical arm is widely applied to various fields of industrial production, logistics transportation and the like. Because the external environment facing the mechanical arm is complex, the mechanical arm is inevitably collided by external force in the working process. If the external force applied to the mechanical arm cannot be accurately detected, the mechanical arm cannot respond to the external force such as collision, and therefore the work of the mechanical arm is affected. Therefore, how to accurately detect the external force applied to the mechanical arm is very important for the mechanical arm. Disclosure of Invention In view of the above, the present application provides a method for determining an external force applied to a mechanical arm, and a computer-readable storage medium, which can accurately detect the external force applied to each connecting rod of the mechanical arm. In a first aspect, the application provides a method for determining an external force applied to a mechanical arm, wherein the mechanical arm comprises a plurality of connecting rods and a plurality of joints which are sequentially connected, the connecting rods are connected through the joints, six-degree-of-freedom force and moment sensors are arranged in the joints at the two ends of at least part of the connecting rods, and the six-degree-of-freedom force and moment sensors are used for sensing forces and moments acting on the corresponding joints; the method comprises the steps of determining motion state parameters of each connecting rod, determining inertia force and moment of inertia of a target connecting rod at a centroid according to the motion state parameters and the inertia attribute parameters of each connecting rod, acquiring force and moment between two ends of the target connecting rod and corresponding joints through the six-degree-of-freedom force and moment sensor, and determining external force born by the target connecting rod according to the inertia force and moment of inertia of the target connecting rod at the centroid and the force and moment between two ends of the target connecting rod and corresponding joints. In some embodiments, the determining the motion state parameter of each of the connecting rods comprises: Acquiring connection parameters of each joint and angle information of each joint, wherein the connection parameters are parameters representing spatial position relations of two adjacent connecting rods, and the angle information of each joint comprises joint angular position, joint angular speed and joint angular acceleration And determining the motion state parameter of each connecting rod according to the principle of robot dynamics according to the inertia attribute parameter of each connecting rod, the connection parameter of each joint and the angle information of each joint. In some embodiments, each connecting rod is provided with an inertial measurement unit for measuring the angular velocity, the angular acceleration and the linear acceleration of the corresponding connecting rod, and the determining the motion parameter of each connecting rod includes acquiring the motion state parameter of each connecting rod from the inertial measurement unit. In some embodiments, implementing the determination of the inertial force and moment of inertia of the target connecting rod at the centroid based on the motion state parameter and the inertial property parameter of each connecting rod includes determining the inertial force and moment of inertia of the target connecting rod at the centroid based on the motion state parameter and the inertial property parameter of each connecting rod using a reverse recurrence equation in an iterative Newton-Euler equation. In some embodiments, the determining the external force to which the target connecting rod is subjected based on the inertial force and the moment of inertia of the target connecting rod at the centroid and the force and moment between the two ends of the target connecting rod and the corresponding joints includes determining a first difference between the inertial force of the target connecting rod at the centroid and the force between the two ends of the target connecting rod and the corresponding joints, and determining the first difference as the magnitude and direction of the external force to which the target connecting rod is subjected. In some embodiments, the method further comprises determining a net moment at a reference point of the target connecting rod based on a second difference between the moment between the two ends of the target connecting rod and the corresponding joints and the moment of