Follower Vehicle Path Following Using Dynamic Curvature and Speed Control
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Solution Overview
Problem
Maintaining vehicle formation, especially on curved paths or turns, is challenging due to the need to balance formation distance and speed, with existing techniques often compromising between these factors depending on the application.
Innovation Solution
A method that involves defining a dynamic zone around the lead vehicle with a radius equal to the desired formation distance, determining the next speed and commanded curvature of the follower vehicle based on its position relative to this zone and the lead vehicle's path, and outputting these parameters to the follower vehicle's control system to maintain the desired formation distance and follow the pre-planned path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the follower vehicle maintains a fixed formation distance from the lead vehicle, then the formation stability is improved, but the follower vehicle cannot adapt to curved paths or turns effectively
Solution Approach 1:
The patent applies dynamics by transitioning from a static formation distance to a dynamic formation distance that adapts to the lead vehicle's path curvature. The system continuously calculates the desired formation distance based on the lead vehicle's position, speed, and curvature, allowing the follower vehicle to maintain stable formation while adapting to curved paths and turns.
2Reliability
If the follower vehicle follows the lead vehicle at a safe speed, then the safety is improved, but the formation distance maintenance becomes compromised
Solution Approach 1:
The system changes parameters dynamically by adjusting the desired formation distance based on path curvature and speed conditions. When the lead vehicle travels on curved paths or at varying speeds, the system modifies the formation distance parameter to balance safety requirements with formation maintenance, rather than using a fixed distance.
3Measurement precision
If the desired formation distance is reduced for better path following, then the path following accuracy is improved, but the safety margin between vehicles is reduced
Solution Approach 1:
The system uses dynamic adjustment of formation distance based on real-time conditions. During straight path segments, the follower maintains a larger safety margin, while during curved paths or turns, the formation distance is dynamically reduced to improve path following accuracy. This dynamic approach balances safety margins with path following precision.
Data Source
AI summary
A method of maintaining vehicle formation includes receiving a desired along path distance; receiving a plurality of waypoints corresponding to a plurality of positions along a path of the lead vehicle; determining a dynamic path for the follower vehicle by spline fitting the plurality of positions of the plurality of waypoints; determining a commanded curvature of the follower vehicle based on a curvature of the dynamic path at a current position of the follower vehicle; determining a current along path distance between the lead vehicle and the follower vehicle; determining an along path error; determining a next speed of the follower vehicle based on the along path error and the respective waypoint speed of the respective waypoint that is adjacent to a current position of the follower vehicle; and outputting the commanded curvature and the next speed to a control system of the follower vehicle.