State-Time Trajectory Planning for Dynamic Obstacle Avoidance
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Solution Overview
Problem
Conventional trajectory planning methods for autonomous driving robots focus on minimizing distance and time but fail to ensure safety by not considering collisions with obstacles, leading to inefficient navigation and potential collisions in dynamic environments.
Innovation Solution
An obstacle avoidance method in a state-time space that calculates a forward trajectory based on a safe timed configuration region, cancels parts of the trajectory when collisions are inevitable, and replans a path through an interim target to ensure collision avoidance, reducing calculation time and improving success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional trajectory planning methods minimize distance and time, then productivity is improved, but reliability deteriorates due to collision risks with obstacles
Solution Approach 1:
The patent extends the traditional state space by introducing a time dimension, transforming a 2D configuration space into a 3D state-time space. This dimensional extension allows the trajectory planner to simultaneously optimize for speed while ensuring safety by checking collisions at multiple time points along the trajectory, thus resolving the contradiction between productivity and reliability.
Solution Approach 2:
The system performs preliminary collision checks at multiple time points before finalizing the trajectory. By evaluating potential collisions in advance at different time instances and adjusting the trajectory accordingly, the system ensures safety is built into the planning process rather than added as a post-processing constraint, maintaining both speed and reliability.
2Reliability
If global trajectory planning searches all spaces for optimal trajectory, then reliability is improved, but loss of time increases due to extensive calculation
Solution Approach 1:
The patent segments the trajectory planning process into discrete time steps, evaluating the trajectory at multiple specific time points rather than continuously searching the entire space. This segmentation allows the system to verify optimality at key moments while significantly reducing the computational burden of exhaustive search, thus balancing reliability with time efficiency.
Solution Approach 2:
Instead of performing exhaustive search at every possible point, the system performs partial checks at strategically selected time points along the trajectory. This partial action approach provides sufficient confidence in trajectory optimality and safety without the prohibitive computational cost of complete exhaustive search, resolving the time-quality tradeoff.
3Reliability
If local trajectory planning avoids obstacles in real time, then reliability is improved, but productivity decreases due to frequent recalculation
Solution Approach 1:
The patent maintains continuous monitoring of the trajectory at multiple time points, allowing the system to detect obstacle encroachments at any stage of trajectory execution. This continuous action enables real-time obstacle avoidance while maintaining navigation efficiency by only recalculating when necessary, rather than performing full recalculation cycles frequently.
Solution Approach 2:
The system implements feedback by continuously checking collision conditions at multiple time points during trajectory execution. When an obstacle is detected at any time point, the system provides feedback to trigger localized trajectory adjustment, maintaining safety while minimizing the computational overhead of frequent full recalculations, thus preserving productivity.
Data Source
AI summary
The present invention relates to an obstacle avoiding method in a state-time space, a recording medium storing a program for employing the same, and a computer program stored in a medium for employing the same. More particularly, the present invention relates to an obstacle avoiding method in a state-time space, a recording medium storing a program for employing the same, and a computer program stored in a medium for employing the same, wherein a forward trajectory is calculated on the basis of a safe timed configuration region, when collision is expected while calculating the forward trajectory, a part of the calculated forward trajectory is canceled, and a forward trajectory passing through an interim target is calculated, and thus a time required for calculating is reduced and a trajectory and success rate to the destination target state is ensured so as to obtain improvement in performance.