Robot Trajectory Planning With Posture Interpolation for Object Stability
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Solution Overview
Problem
Existing trajectory planning devices for robots do not consider the hand posture, leading to abrupt changes that may damage gripped objects, and delayed control times to mitigate damage result in extended cycle times and reduced productivity.
Innovation Solution
A trajectory plan generation device that includes a processor to execute a program for generating a trajectory plan by searching for position and posture candidates using spherical interpolation, determining trajectory information, and outputting data that stabilizes the object being held, while avoiding obstacles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If trajectory planning is performed without considering hand posture, then the trajectory calculation is simple and fast, but the gripped object may be damaged due to abrupt posture changes
Solution Approach 1:
The trajectory planning is divided into two independent search processes: one for position candidates and another for posture candidates. This segmentation allows each search to focus on its specific aspect, maintaining computational efficiency while ensuring both position and posture are optimized for object stability.
Solution Approach 2:
Multiple position and posture candidates are generated in advance through parallel search processes before final trajectory determination. This preliminary generation of candidates allows the system to pre-evaluate multiple options and select the optimal combination that ensures object stability without compromising calculation speed.
2Reliability
If control time is extended to reduce damage to gripped object, then object stability is improved, but cycle time is extended and productivity is reduced
Solution Approach 1:
Multiple trajectory candidates are generated in advance with different control time characteristics. The system can select from pre-computed options that balance object stability with acceptable cycle times, avoiding the need for extended real-time control calculations.
Solution Approach 2:
The system varies parameters such as discretization width and search depth to generate multiple trajectory candidates with different control time requirements. This allows selection of trajectories that achieve sufficient object stability within acceptable productivity constraints.
3Manufacturing precision
If multiple position and posture candidates are searched and determined, then trajectory accuracy and object stability are improved, but calculation complexity increases
Solution Approach 1:
The complex search space is segmented into position search and posture search, which are conducted independently and then combined. This reduces the complexity of each individual search while maintaining the ability to find accurate trajectories through the combination of results.
Solution Approach 2:
The system performs searches with controlled discretization widths that are sufficient to find acceptable trajectories without exhaustively searching every possible position and posture combination. This partial action approach achieves good enough accuracy with manageable computational complexity.
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
The solution allows for the stabilization of objects being held by the robot, reducing the risk of damage and minimizing cycle times, thereby enhancing productivity by planning smooth and stable robot arm movements.
Implementation Method 1
a second search process for searching for a plurality of posture candidates of the tip portion that change within an allowable range by spherical interpolation based on postures of the tip portion at the start point and the end point
Data Source
AI summary
A trajectory plan generation device executes a first search process for searching for a plurality of position candidates which are movement destinations of the tip portion within a predetermined distance from first trajectory information indicating positions and postures of the tip portion between the start point and the end point, a second search process for searching for a plurality of posture candidates of the tip portion that change within an allowable range by spherical interpolation based on postures of the tip portion at the start point and the end point, a determination process for determining second trajectory information indicating positions and postures of movement destinations of the tip portion from the first trajectory information based on the plurality of position candidates searched for by the first search process and the plurality of posture candidates searched for by the second search process, and an output process.