Mobile Body Trajectory Control Using Posture-Based Waypoint Selection
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Solution Overview
Problem
Mobile bodies operating based on pre-defined moving paths face challenges in maintaining smooth movement due to discrepancies between planned and actual positions and postures.
Innovation Solution
An information processing apparatus with a position information acquisition unit, posture information acquisition unit, and a mobile body controller that generates a target trajectory with waypoints, selects a reference point based on proximity and posture differences, and adjusts speed command values to ensure smooth movement by regenerating the trajectory when errors exceed thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mobile body runs on a pre-defined moving path with speed and position set in advance, then the movement control is simplified, but the movement smoothness deteriorates due to discrepancies between planned and actual positions and postures
Solution Approach 1:
The system dynamically adjusts the reference point selection based on real-time position and posture information. Instead of using a fixed reference point approach, the mobile body controller continuously extracts waypoints within threshold distance and selects the most appropriate reference point based on current posture, making the control system adaptive to actual movement conditions and maintaining smoothness.
Solution Approach 2:
The system uses feedback from actual position and posture information to adjust the reference point selection and speed command values. By comparing planned versus actual states and using this feedback to modify control parameters in real-time, the system resolves discrepancies and maintains smooth movement while keeping control logic relatively simple.
2Device complexity
If the reference point is selected based on nearest distance only, then the selection process is simplified, but the trajectory tracking accuracy deteriorates due to posture differences
Solution Approach 1:
The system changes the selection criteria from solely distance-based to a composite evaluation considering both distance and posture alignment. By introducing posture difference as an additional parameter in the selection process, the system achieves more accurate trajectory tracking without significantly increasing computational complexity, as it evaluates multiple waypoints against two parameters rather than one.
3Device complexity
If the speed command value is not adjusted, then the control process is simpler, but the movement smoothness deteriorates at waypoints with dead band speed
Solution Approach 1:
The system performs preliminary adjustment of speed command values before the mobile body reaches waypoints where speed changes are anticipated. By comparing speed command values of adjacent waypoints in advance and pre-adjusting for dead band conditions, the system ensures smooth transitions without adding complex real-time control logic during actual movement.
4Measurement precision
If the threshold distance is set to a small value, then the reference point selection is more precise, but the responsiveness to position changes deteriorates
Solution Approach 1:
The system extracts multiple waypoints within a threshold distance rather than selecting a single nearest point. This partial approach (selecting from multiple candidates rather than one) provides both precision through evaluation of several points and responsiveness through having multiple reference options available, resolving the contradiction between precision and responsiveness.
Data Source
AI summary
An information processing apparatus, an information processing method, and a program that allow smooth movement of a mobile body. The information processing apparatus includes a position information acquisition unit, a posture information acquisition unit, a generation unit, and a mobile body controller. The position information acquisition unit acquires position information of a mobile body. The posture information acquisition unit acquires posture information of the mobile body. The generation unit generates a target trajectory to a target point, the target trajectory including a plurality of waypoints each including waypoint information including a position command value and a posture command value for the mobile body. The mobile body controller extracts waypoints existing within a threshold distance from the mobile body using the position information and the position command value, selects a waypoint having a smallest difference between the posture command value, and sets the waypoint as a reference point.