Robot Arm Direct Teaching With Gradual Speed Constraint Relaxation
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Solution Overview
Problem
Existing direct teaching devices for robots often result in the robot arm moving at a higher speed than expected, leading to deteriorated operability due to the smoothing of operation from a stop state.
Innovation Solution
A teaching method and robot system that detect external force applied to the robot arm, drive it with force control, and gradually relax restrictive conditions such as upper limit speed based on elapsed time or movement amount, allowing for controlled movement and improved operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the viscosity coefficient is changed according to operation state to smooth movement from stop, then operability is improved, but the robot arm speed becomes higher than expected which deteriorates operability
Solution Approach 1:
The patent applies dynamics by making the viscosity coefficient change dynamically based on the operation state of the robot arm. Specifically, the viscosity coefficient is adjusted according to whether the arm is starting from rest or already in motion, allowing the system to adapt its mechanical characteristics in real-time to achieve smooth acceleration while preventing excessive speed
Solution Approach 2:
The patent implements parameter changes by modifying the viscosity coefficient - a key force control parameter - based on operational conditions. When the robot arm is stationary, a higher viscosity coefficient provides resistance to prevent sudden movements, while when the arm is already moving, the coefficient is reduced to allow smoother operation, thus resolving the contradiction between operational smoothness and speed control
2Productivity
If force control is applied to enable direct teaching, then teaching efficiency is improved, but the robot arm may move at higher speed than expected reducing safety
Solution Approach 1:
The patent implements feedback mechanisms by continuously monitoring the operation state of the robot arm (whether it is starting from rest or already in motion) and adjusting the viscosity coefficient accordingly. This closed-loop control ensures that the force control system responds appropriately to operational conditions, maintaining safety while preserving teaching efficiency
Solution Approach 2:
By dynamically adjusting the viscosity coefficient based on real-time operational state, the system maintains force control benefits for teaching efficiency while preventing unsafe high-speed movements. The dynamic parameter adjustment creates a safety mechanism that adapts to the current operational context
Data Source
AI summary
A teaching method for detecting external force applied to a robot arm, driving the robot arm with force control based on the external force, and teaching a position and a posture of the robot arm, the teaching method including gradually relaxing, according to an elapsed time from when operation of the robot arm is started or a movement amount of the robot arm from when the operation of the robot arm is started, a restrictive condition for restricting the driving of the robot arm.