Vehicle Formation Offset Control on Curved Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Maintaining vehicle formation, especially on curved paths or turns, is challenging due to the tradeoff between maintaining formation and following at a safe speed, with existing techniques often failing to synchronize task completion and offset maintenance in agricultural and construction applications.
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 the dynamic zone and pre-planned path, and outputting these to the control system to navigate the follower vehicle while maintaining the desired formation distance and offset.
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 implements dynamic formation distance adjustment by calculating the desired formation distance as a function of the lead vehicle's curvature. The system continuously updates the formation distance parameter based on real-time curvature measurements, allowing the follower vehicle to adapt its position dynamically during turns while maintaining stable formation during straight-line travel. This resolves the contradiction by making the formation distance a dynamic parameter rather than a fixed value.
Solution Approach 2:
The system changes the formation distance parameter based on the lead vehicle's curvature state. When the lead vehicle is on a curved path, the formation distance is adjusted proportionally to the curvature magnitude. This parameter change allows the follower vehicle to maintain appropriate distance during turns while preserving formation stability during straight-line operation, effectively resolving the adaptability-stability contradiction.
2Reliability
If the follower vehicle follows the lead vehicle at a reduced speed to maintain safe speed, then the safety is improved, but the task completion time increases
Solution Approach 1:
The patent implements dynamic speed adjustment where the follower vehicle's speed is continuously adapted based on real-time formation distance errors and lead vehicle speed. The speed controller dynamically adjusts the follower speed to maintain safe following distance while minimizing speed reduction, allowing the system to adhere to safety requirements without excessive time loss. The dynamic nature of the speed control allows optimal balance between safety and efficiency.
Solution Approach 2:
The system uses feedback control where the follower vehicle continuously monitors the actual formation distance and adjusts its speed based on the error between desired and actual distance. This feedback mechanism ensures safe speed adherence by automatically reducing speed when formation distance becomes too small, while allowing faster speeds when safe distance is maintained, thus minimizing unnecessary time loss while ensuring safety.
3Productivity
If the follower vehicle maintains a desired offset from the lead vehicle, then the task coordination is improved, but the formation maintenance becomes more challenging on curved paths
Solution Approach 1:
The patent adjusts the desired offset parameter dynamically based on the lead vehicle's curvature. The offset is modified proportionally to the curvature magnitude, allowing the follower vehicle to maintain coordinated task position during turns while simplifying the control logic. This parameter adaptation reduces the complexity of maintaining formation on curved paths by providing a straightforward relationship between curvature and required offset adjustment.
Solution Approach 2:
The system implements dynamic offset adjustment where the desired lateral offset between lead and follower vehicles is continuously updated based on real-time curvature measurements. This dynamic offset maintenance allows coordinated task completion during turns while using a simple proportional relationship between curvature and offset, avoiding complex control algorithms and reducing overall system complexity.
Data Source
AI summary
A method of maintaining vehicle formation includes receiving a desired cross track offset distance and a desired along track offset distance between a lead vehicle and a follower vehicle; receiving a current position, a current yaw rate, and a current speed of the lead vehicle; determining a current turn radius of the lead vehicle based on the current yaw rate and the current speed of the lead vehicle; determining a projected turn radius of the follower vehicle based on the current turn radius of the lead vehicle, the desired cross track offset distance, and the desired along track offset distance; determining a commanded curvature and a next speed of the follower vehicle based on a current position of the follower vehicle and the projected turn radius of the follower vehicle; and outputting the next speed and the commanded curvature to a control system of the follower vehicle.