Robot Hand Route Control for Dense Object Transfer Near Obstacles
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Solution Overview
Problem
Object handling devices with robot arms face challenges in avoiding collisions with obstacles during object transfer, which can damage the hand or object and reduce efficiency, due to inaccuracies in measurement and operational speed.
Innovation Solution
An object handling control device that sets and navigates through defined regions (first, second, and third regions) using object and status information, employing force control to prevent collisions by pressing against obstacles and repulsively moving away when necessary, allowing for efficient and safe transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operational speed of the arm or hand is lowered in the entire moving route or in an area in the vicinity of the obstacle to reduce collision impact, then the damage risk is reduced, but the work efficiency is lowered
Solution Approach 1:
The moving route is divided into multiple regions (first region, second region, third region) with different speed restrictions. The hand is allowed to move at high speed in the first region away from obstacles, slows down in the second region approaching obstacles, and stops in the third region near obstacles. This segmented approach allows high work efficiency in safe zones while ensuring safety near obstacles.
Solution Approach 2:
Different speed control strategies are applied to different spatial locations along the moving route. Instead of uniformly lowering speed throughout the entire route, the system applies localized speed restrictions only in regions where collision risk exists, maintaining high speed in safe regions to preserve overall work efficiency.
2Reliability
If the moving route is planned to ensure a distance to the obstacle by estimating larger virtual sizes, then the collision risk is lowered, but it becomes impossible to plan the moving route when the hand is to enter a narrow gap or densely arrange the objects
Solution Approach 1:
The system dynamically adjusts the virtual size of the hand based on the spatial context. In narrow gaps or densely arranged object scenarios, the virtual size is reduced to allow route planning in tight spaces. In other regions, the virtual size is increased to maintain safety margins. This dynamic adjustment enables the system to adapt to different spatial constraints while managing collision risk.
Solution Approach 2:
The virtual size parameter of the hand is changed according to the local environment. When approaching narrow gaps or densely packed objects, the system reduces the virtual size parameter to enable feasible route planning. This parameter change allows the hand to navigate tight spaces that would be impossible with a fixed large virtual size, while still maintaining safety through force control in the third region.
3Reliability
If force control is used to repulsively move the robot away from interfering obstacles, then collision prevention is achieved, but the hand or grasped object may still be damaged through the repulsive motion depending on the speed at the time of collision
Solution Approach 1:
The system performs preliminary speed reduction in the second region before the hand reaches the third region where force control is activated. By the time collision detection triggers repulsive motion in the third region, the hand is already moving at reduced speed, which significantly reduces the impact force and potential damage during the repulsive motion while maintaining effective collision prevention.
Data Source
AI summary
An object handling control device includes one or more processors configured to acquire at least object information and status information representing an initial position and a destination of an object; set, when a grasper grasping the object moves from the initial position to the destination, a first region, a second region, and a third region in accordance with the object information and the status information; and calculate a moving route along which the object is moved from the initial position to the destination with reference to the first region, the second region, and the third region.