Robot Impedance Control for Contact-Triggered Orientation Switching
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Solution Overview
Problem
Robots may collide with obstacles on evacuation paths or experience excessive speed changes due to external forces, leading to operational inefficiencies and potential interference with human activities.
Innovation Solution
A robot system with a controller that switches between states to manage orientation changes based on external force detection, using impedance control to vary rigidity and viscosity parameters, allowing controlled orientation changes and preventing collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the robot is decelerated or stopped in response to contact with human beings, then safety is improved, but the robot remains in work areas and impedes human works
Solution Approach 1:
The robot dynamically changes its state between first state (restricted orientation change) and second state (tolerant orientation change) based on detected external force. When external force is detected, the controller switches to the second state allowing orientation change in the force direction, then returns to the first state after a predetermined time elapses, enabling the robot to respond adaptively to human contact while maintaining operational efficiency
Solution Approach 2:
The controller changes the rigidity parameter of the robot's impedance control system based on detected external force. In the first state, the robot has higher rigidity with restricted orientation change, while in the second state, the robot has lower rigidity allowing orientation change in the direction of applied force, optimizing both safety and work efficiency
2Object-affected harmful factors
If the robot performs evacuation operation by moving in the direction where external force is decreased, then collision with obstacles is reduced, but excessive speed changes occur
Solution Approach 1:
The robot performs a two-phase response: first allowing orientation change in the direction of external force (second state) to avoid obstacles, then restricting orientation change (first state) to stabilize speed. This dynamic state switching enables the robot to evade obstacles while preventing excessive speed changes that would occur with continuous evacuation movement
Solution Approach 2:
The controller implements periodic state switching with a predetermined time interval. After detecting external force and switching to the second state for obstacle avoidance, the controller automatically returns to the first state after the predetermined time elapses, creating a rhythmic pattern of response that balances collision prevention with speed stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances robot operation by allowing controlled orientation changes and preventing collisions, improving safety and efficiency in collaborative environments.
Implementation Method 1
using impedance control to vary rigidity and viscosity parameters
Data Source
AI summary
In a system including a robot and a controller controlling the robot, the controller switches the robot from a first state to a second state in which orientation change in accordance with external force applied to the robot is more tolerated than the first state based on detection of contact of an object with the robot. The controller switches the robot from the second state to a third state in which the orientation change in accordance with the external force is more restricted than the second state after the orientation change in accordance with the external force applied to the robot is started and while the external force is being applied to the robot.