Robot Hand Path Planning for Shape Changes During Gripping
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Solution Overview
Problem
Existing robot systems face inefficiencies and potential damage when handling bulk-loaded workpieces due to changes in hand shape before and after gripping, leading to increased processing time or interference with containers and peripheral devices.
Innovation Solution
A robot controller with a take-out position calculation unit, spatial information storage, and operation route generation unit that considers both pre- and post-gripping hand shapes to generate efficient operation routes without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the hand shape assumed to generate the operation route is too small with respect to the hand shape after gripping, then the route may be shorter and more efficient, but the hand or workpiece may contact the container or surrounding equipment causing breakage or damage
Solution Approach 1:
The patent applies dynamics by switching between different hand shape models (pre-gripping and post-gripping) depending on the operational phase. The system dynamically selects the appropriate hand shape assumption for route generation: using the pre-gripping hand shape for the approach route and the post-gripping hand shape for the withdrawal route, thereby adapting the safety margin to the actual hand dimensions at each stage of the operation.
2Reliability
If the hand shape assumed to generate the operation route is too large with respect to the hand shape after gripping, then the route will be longer and processing time will increase, but it reduces the risk of contact with containers and peripheral devices
Solution Approach 1:
The patent segments the operation route into two distinct phases: approach route (from hand origin to workpiece) and withdrawal route (from workpiece to destination). Each phase uses a different hand shape assumption appropriate to that phase - pre-gripping shape for approach and post-gripping shape for withdrawal - thereby optimizing the total route efficiency while maintaining safety throughout both phases.
3Device complexity
If a single hand shape is used to generate the operation route without considering shape changes, then the system complexity is reduced, but the hand may come into contact with the container or peripheral devices causing breakage or damage
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple hand shape models (pre-gripping and post-gripping) and storing them in advance. During operation, the appropriate pre-defined hand shape is selected and applied based on the operational phase, eliminating the need for real-time hand shape calculation while ensuring accurate safety margin maintenance throughout the operation.
Data Source
AI summary
This robot control device controls a robot having a hand so that the robot withdraws objects from a randomly stacked pile, and includes a withdrawal position calculating unit, a spatial information storage unit, a shape storage unit, and a motion path generating unit. The withdrawal position calculating unit calculates a withdrawal position of an object to be withdrawn by the robot on the basis of image information from an image capturing device which captures an image including the objects, and the spatial information storage unit stores a movable range in which the robot can operate and an interference range in which the robot interferes with the surroundings in the movable range. The shape storage unit stores the shapes of the robot and the hand, and the motion path generating unit generates a motion path of the hand on the basis of outputs of the withdrawal position calculating unit, the spatial information storage unit, and the shape storage unit such that the robot does not interfere with the surroundings. The shape storage unit stores a pre-gripping hand shape before the hand grips the object and a post-gripping hand shape after the hand grips the object.