Robot End Effector Trajectory Control After Collision
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Solution Overview
Problem
Existing robot collision detection solutions do not effectively prevent damage from collisions by stopping the robot's work after a collision occurs, failing to address potential losses and secondary damage.
Innovation Solution
A method and apparatus determine a robot's end effector trajectory after collision using an impedance control model, based on the collision force and pre-collision trajectory, adjusting the inertia, damping, and stiffness matrices to minimize secondary collisions and restore the robot to its original path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the robot stops work after collision detection, then collision damage is prevented, but productivity is reduced and secondary damage cannot be avoided
Solution Approach 1:
The patent applies dynamics by transitioning from a static stop-action to a dynamic response. The robot controller calculates a new trajectory based on collision force and pre-collision trajectory, enabling the robot to adapt its motion dynamically after collision rather than simply stopping, thus maintaining productivity while ensuring safety.
Solution Approach 2:
The patent changes the parameter of robot motion state from stopped to controlled movement. By computing trajectory points based on collision force magnitude and direction, the system adjusts motion parameters (position, velocity, acceleration) to guide the robot back to the original trajectory, resolving the contradiction between preventing damage and maintaining productivity.
2Productivity
If the robot continues work after collision, then productivity is maintained, but secondary collisions and damage occur
Solution Approach 1:
The patent implements feedback by using collision force information to adjust subsequent motion. The controller continuously monitors collision force and recalculates trajectory points accordingly, creating a closed-loop control system that prevents secondary collisions while maintaining productivity through adaptive trajectory adjustment.
Solution Approach 2:
The patent applies preliminary action by pre-calculating trajectory points before the robot executes motion after collision. The controller computes the entire adjusted trajectory in advance based on collision parameters, allowing the robot to follow a predetermined safe path that avoids secondary collisions while restoring productivity.
3Manufacturing precision
If complex trajectory recalculation is performed after collision, then precise trajectory restoration is achieved, but response time increases
Solution Approach 1:
The patent applies partial action by calculating only the necessary trajectory points needed to return the robot to its original path rather than recalculating the entire trajectory. The controller determines a limited number of intermediate points based on collision force and pre-collision state, achieving sufficient trajectory accuracy without excessive computation time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces secondary damage by controlling the robot's movement post-collision, avoiding further collisions and enabling quick restoration to the original trajectory without additional planning.
Implementation Method 1
The end effector is modeled as an impedance control model, and determining a second trajectory of the end effector based on the obtained collision force of the end effector and a recorded first trajectory of the end effector comprises: determining the second trajectory of the end effector using the impedance control model, based on the obtained collision force and the recorded first trajectory of the end effector.
Data Source
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AI summary
The subject matter relates to a method for determining a trajectory of a robot's end effector, comprising: obtaining a collision force of a robot's end effector caused by a collision of the end effector when the collision is detected; and determining a second trajectory of the end effector based on the obtained collision force of the end effector and a recorded first trajectory of the end effector, wherein the trajectory has trajectory information including a position vector, a velocity vector, and an acceleration vector of each trajectory point, and wherein the first trajectory is a trajectory before the collision, and the second trajectory is a trajectory after the collision. With the method, an efficient protection for the robot and its working environment at the moment of collision may be achieved.