Manipulator Path Conversion Using Curvature Information
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Solution Overview
Problem
Current manipulator control systems fail to accurately follow pre-planned paths specified as splines or Bezier curves due to the lack of consideration for curvature information, leading to deviations in the control path from the original planned trajectory.
Innovation Solution
Incorporating curvature information, such as tangent directions and higher derivatives, into the control path determination process to ensure a more accurate tracing of the planned path, while allowing for a reduction in interpolation points and permitting a specified maximum deviation to maintain path fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the planned path is discretized into control points and interpolated using standard spline functions, then the manipulator control can execute the path, but the control path deviates from the original planned trajectory due to lack of curvature information
Solution Approach 1:
The invention calculates curvature information (tangent vectors, normal vectors, binormal vectors) at each control point before performing spline interpolation. This preliminary preparation of geometric information allows the interpolation algorithm to maintain the original path's curvature characteristics, preventing deviation from the planned trajectory while enabling smooth manipulator execution.
2Manufacturing precision
If curvature information is incorporated into the control path determination, then path accuracy is improved, but computational complexity increases
Solution Approach 1:
The invention divides the planned path into discrete segments between control points, calculating curvature information (tangent, normal, and binormal vectors) for each segment independently. This segmentation allows the complex computational task to be broken down into manageable pieces, where each segment's geometric properties are pre-calculated and stored, reducing the overall computational burden during real-time execution.
Solution Approach 2:
All curvature-related calculations (tangent vectors, normal vectors, binormal vectors) are performed in advance during the path planning phase, before the manipulator executes the path. This preliminary computation stores the geometric characteristics in a lookup table or pre-processed data structure, eliminating the need for complex real-time calculations during execution and significantly reducing computational complexity during operation.
3Manufacturing precision
If more interpolation points are used to maintain path fidelity, then path accuracy is improved, but computational effort and processing time increase
Solution Approach 1:
The invention changes the parameterization of the spline interpolation by incorporating curvature information (tangent, normal, binormal vectors) as additional constraints. Instead of using standard uniform parameterization, the algorithm uses the pre-calculated curvature parameters to guide the interpolation, allowing accurate path following with fewer control points and reducing processing time while maintaining fidelity.
Data Source
Figure 1~2
AI summary
The method involves predetermining a planned path of the manipulator by a path generation unit. A control path is automatically determined based on the planned path through a path conversion unit (2). The control path is separated with the manipulator by a manipulator controller (3). The path conversion unit determines the curvature information of the control path based on curvature information of the planned path. Independent claims are also included for the following: (1) a device for controlling a manipulator, particularly of a robot; and (2) a computer program product with a computer program for executing the method.