Predictive Motion Control Using Virtual Obstacles Between Obstacles
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Solution Overview
Problem
Existing control devices using obstacle evaluation terms struggle to prevent collisions when moving bodies follow target trajectories, often resulting in stationary states or excessively detoured routes.
Innovation Solution
A control device that includes an acquisition part for detecting actual obstacles and a model prediction control part which calculates control inputs using a prediction model, employing a virtual obstacle when multiple obstacles are present to minimize collision risk by adjusting stage costs with a virtual obstacle evaluation term.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the evaluation function including the obstacle evaluation term for each obstacle is used, then the moving body can avoid obstacles, but the moving body may come into a stationary state or make large detours
Solution Approach 1:
The patent introduces a virtual obstacle as an intermediary element that mediates between multiple actual obstacles. Instead of directly evaluating each actual obstacle separately, the virtual obstacle synthesized from multiple actual obstacles acts as a mediator to guide the moving body, preventing stationary states and large detours while maintaining collision avoidance reliability
Solution Approach 2:
The patent changes the parameter representation by transforming multiple actual obstacle positions into a virtual obstacle position through synthesis. This parameter transformation allows the evaluation function to work more effectively by representing multiple obstacles as a single virtual obstacle, improving movement efficiency while maintaining collision avoidance
2Adaptability or versatility
If the evaluation function including the obstacle evaluation term is simply used, then the obstacle avoidance can be implemented, but the collision with the obstacle cannot be avoided suitably in cases where two obstacles clamp the target trajectory
Solution Approach 1:
The patent merges multiple actual obstacles that clamp the target trajectory into a single virtual obstacle through synthesis. This combining approach allows the evaluation function to properly handle situations where multiple obstacles surround the target trajectory, improving collision avoidance reliability by treating the clustered obstacles as a unified virtual obstacle rather than separate entities
Data Source
AI summary
A model prediction control part of a control device includes an obstacle avoidance control unit that operates when there are a plurality of actual obstacles to be avoided. The obstacle avoidance control unit decides the position of a virtual obstacle from the positions of the plurality of actual obstacles acquired by an acquisition part so as to be positioned between the plurality of actual obstacles, and performs model prediction control by using, as the stage cost, the addition result of a standard cost and a virtual obstacle evaluation term for which a prescribed function, which uses, as parameters, at least the position of the virtual obstacle and the position of a moving body, is multiplied by a virtual obstacle weight. Using this configuration, when the moving body is caused to follow with respect to a target trajectory by the model prediction control, a collision with an obstacle can be avoided suitably.