Robot Trajectory Planning via Inverse Kinematics
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Solution Overview
Problem
Conventional robot movement planning methods require high computing time and are prone to collisions due to straight trajectory calculations in the stationary base coordinates system, especially in articulated arm kinematics, and are not user-plausible for curved movements.
Innovation Solution
Planning a trajectory for a robot's spatial point in a stationary coordinates system using inverse kinematics to translate spatial positions into configuration positions, testing for collisions, and forming collision-free trajectories in a three-dimensional space with straight elements, allowing for efficient and user-acceptable path planning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If straight trajectory elements are used in the configuration room, then the planning effort and computing time are reduced, but the actual movement path becomes significantly curved in the stationary base coordinates system, increasing collision likelihood
Solution Approach 1:
The patent inverts the conventional planning approach by planning the trajectory directly in the stationary base coordinates system (workspace) rather than in the configuration room. This inversion allows straight trajectory elements to be defined in the workspace where they remain straight and collision-free, while the corresponding configuration path may be curved. The inverse kinematics are then used to translate workspace positions to configuration positions, resolving the contradiction between straight paths and collision freedom.
2Reliability
If multiple configuration positions are tested to find a collision-free trajectory, then collision freedom is ensured, but the planning effort and computing time increase significantly
Solution Approach 1:
The patent reverses the conventional approach by planning trajectories in the stationary base coordinates system where collision detection is more intuitive and efficient. By defining the trajectory directly in workspace coordinates and using inverse kinematics to obtain configuration positions, the method reduces the number of collision tests needed while ensuring collision-free movement, thus improving planning efficiency without sacrificing reliability.
3Reliability
If curved movements are planned in the stationary base coordinates system, then collision freedom can be achieved, but the movement path becomes implausible and unacceptable to persons and operating personnel
Solution Approach 1:
The patent plans the trajectory directly in the stationary base coordinates system (workspace) where straight line paths can be defined between start and target positions. These straight paths in workspace coordinates correspond to physically plausible movements that are intuitive and acceptable to users, while still ensuring collision freedom. The inverse kinematics translation to configuration positions maintains the straight appearance in the workspace view.
Data Source
AI summary
A method for computer-aided movement planning of a robot is provided, in which a trajectory for the movement of a spatial point assigned to the robot is planned in a fixed coordinates system. The spatial positions are translated from a plurality of spatial positions of the spatial point into respective configuration positions in a configuration room of the robot based on inverse kinematics. The respective configuration positions are described by axial positions of one or several rotatory or translational movement axes of the robot and are tested for collisions and a trajectory is formed along spatial positions of the spatial point, the respective configuration positions of which are collision-free. Planning the movement in a fixed coordinates system improves the efficiency of the planning method and the planned movement corresponds more to the expectations of the persons or the operating staff in the surroundings of the robot.