Robot Arm Holding Motion Control via Contact Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power assisting robots face safety issues when switching between states of conveying and not conveying an object, as they may move unintentionally due to unintended force detection, leading to difficulties in safely holding objects.
Innovation Solution
A robot system equipped with a holder, contact detector, contact condition detector, and holding motion selecting unit that temporarily stops and adjusts motion based on detected contact conditions and applied force to ensure safe object handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the robot arm contacts the object to hold it, then the robot can achieve holding function, but unintended force detection causes the robot to move in unintended direction or be hard to be pressed against the object
Solution Approach 1:
The robot arm switches between different motion modes (continuously stopped motion, directionally limited motion, directionally unlimited motion) based on contact conditions detected during operation. This dynamic adaptation allows the system to respond appropriately to varying contact scenarios, maintaining safety while enabling effective holding functionality.
Solution Approach 2:
A contact condition detector measures the distance between the object and holder upon contact, providing feedback to the holding motion selecting unit. This feedback mechanism enables the system to adjust its motion mode based on real-time contact conditions, preventing unintended movement while ensuring proper holding.
2Ease of operation
If the robot arm moves freely in all directions, then the robot is easy to manipulate, but the robot may move in unintended direction when contact force is detected
Solution Approach 1:
The motion control system dynamically adjusts the degree of freedom of the robot arm based on contact conditions. When contact is detected, the system transitions from directionally unlimited motion to directionally limited motion or continuously stopped motion, thereby maintaining manipulability while preventing unintended movement.
Solution Approach 2:
The system changes the motion parameters (directional limitations, stopping conditions) of the robot arm based on detected contact conditions. By modifying these parameters in response to contact, the system maintains ease of manipulation while ensuring accurate motion control and preventing unintended movement.
3Reliability
If the robot arm stops immediately upon contact, then safety is improved, but the holding function cannot be achieved
Solution Approach 1:
The robot arm implements dynamic stopping behavior based on contact conditions. Rather than always stopping immediately, the system selects from multiple motion modes including continuously stopped motion, directionally limited motion, and directionally unlimited motion, allowing the holding function to be achieved while maintaining safety through conditional stopping.
Solution Approach 2:
The contact condition detector measures the distance between the object and holder upon contact, providing preliminary information about the contact state. This preliminary detection enables the system to make informed decisions about whether to stop or continue motion, ensuring both safety and effective holding functionality.
Data Source
AI summary
A robot arm temporarily stops when a contact detector detects contact. A holding motion selecting unit then selects one of continuously stopped motion, directionally limited motion, and directionally unlimited motion in accordance with information including one or both of a distance between the robot arm and a contacted object and force applied to the robot arm by a person. A motion controller causes the selected motion to achieve holding motion.