Robot Trajectory Planning Around Moving Obstacles
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Solution Overview
Problem
Existing motion planning methods for robots fail to effectively navigate in environments with dynamic obstacles, where obstacles' positions change over time, leading to increased collision risks and reduced performance.
Innovation Solution
A method for planning and controlling the motion of robots that involves defining start and destination configurations, determining robot motions to maintain a predetermined distance from dynamic obstacles, using a state space or hyperspace with a time dimension to optimize trajectories, and employing algorithms like A* to minimize collisions and computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motion planning methods are used for robots in environments with dynamic obstacles, then collision risk increases and performance decreases, but if no motion planning is used, then robots cannot navigate effectively
Solution Approach 1:
The patent applies dynamics by making the motion planning system adaptive to changing environments. The robot continuously updates its understanding of dynamic obstacles and recalculates trajectories in real-time, transforming a static planning approach into a dynamic one that responds to environmental changes while maintaining both safety and efficiency
Solution Approach 2:
The patent introduces time as an additional dimension to the state space, transforming traditional 2D spatial path planning into 4D spacetime trajectory planning. This dimensional expansion allows the robot to reason about when obstacles will be in certain positions, enabling proactive collision avoidance while optimizing navigation speed and efficiency
2Reliability
If complex motion planning algorithms are used to handle dynamic obstacles, then collision avoidance improves, but computational complexity increases
Solution Approach 1:
The patent segments the motion planning problem into distinct phases: prediction of obstacle trajectories, state space construction with time dimension, trajectory optimization, and execution. This segmentation allows each sub-problem to be solved with appropriate algorithms, reducing overall computational complexity while maintaining collision avoidance reliability
Solution Approach 2:
The patent employs heuristic functions and cost functions that prioritize safe trajectories, guiding the search algorithm toward collision-free paths without exhaustively exploring all possibilities. This heuristic guidance reduces computational complexity by pruning irrelevant search branches while guaranteeing optimal or near-optimal solutions
3Reliability
If trajectories are optimized to avoid dynamic obstacles, then collision risk decreases, but arrival time may be delayed
Solution Approach 1:
The patent performs preliminary action by predicting future obstacle positions and pre-calculating safe trajectories before the robot actually encounters obstacles. The system proactively plans avoidance paths based on predicted obstacle motion, allowing the robot to maintain optimal speed while already positioned to avoid collisions, thus minimizing time loss
Solution Approach 2:
The patent optimizes trajectory parameters by adjusting speed, direction, and timing to minimize deviation from the original path. The cost function balances safety margins with travel time, finding trajectories that achieve collision avoidance with minimal detours and speed reductions, thereby reducing arrival time delays
Data Source
Figure 1a~1d
Figure 2~4
AI summary
A method for path and/or trajectory planning for at least one mobile or fixed robot (R1) comprising the steps of: - Providing (S10) a start configuration comprising at least one start position (x1,y1) and a destination configuration comprising at least one destination position (x3,y1) for the robot; - Providing (S20) a motion of at least one obstacle (O) and/or a further robot (R2) in the workspace of the first robot (R1), defining a position varying over time of the obstacle (x3,y1 ; x1,y1) and/or further robot (x3,y2 ; x1,y2); and - Determining (S30, S60) a path and/or trajectory of the first robot (R1) and the further robot (R2) from its start configuration to its destination configuration, wherein at each point in time a distance between the first robot (R1) and the obstacle (o) and/or the further robot (R2) does not fall below a predetermined threshold, so that a collision is avoided.