Robot Control Apparatus for Safe Teaching Mode Contact Handling
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Solution Overview
Problem
In robot systems where a worker collaborates with a robot without a safety fence, there is a challenge in efficiently teaching the robot's trajectory while avoiding contact with surrounding objects, as automatic retreat operations can disrupt the teaching process and lead to repeated contact with workpieces, prolonging teaching time and potentially causing damage.
Innovation Solution
A robot control apparatus with a contact detection unit to determine if the robot is in contact with an object, an operation direction monitor unit to set a permissible range for the robot's operation direction, and a selector switch to switch between teaching and playback modes, allowing for safe and controlled retreat operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the robot automatically performs a retreat operation when contact is detected, then safety is improved, but teaching efficiency deteriorates due to repeated contact and prolonged teaching time
Solution Approach 1:
The control apparatus dynamically switches between teaching mode and playback mode based on operational context. In teaching mode, the robot allows manual operation without automatic retreat. In playback mode, automatic retreat is enabled for safety. This dynamic adaptation resolves the contradiction by allowing safety features to be context-dependent rather than fixed.
Solution Approach 2:
The system changes the operational parameters of the robot by switching modes. In teaching mode, the retreat threshold and response behavior are disabled or modified. In playback mode, the original safety parameters are restored. This parameter switching allows the same hardware to satisfy both safety requirements and teaching efficiency needs.
2Reliability
If the robot is stopped when contact with an outside object is detected, then safety is improved, but the contact state continues and the robot cannot be operated, causing teaching to be interrupted
Solution Approach 1:
The system dynamically adjusts its response to contact detection based on the operational mode. In teaching mode, contact detection does not trigger an emergency stop that prevents further operation. Instead, the system allows continued teaching operations while monitoring contact states, enabling teaching continuity while maintaining safety awareness.
Solution Approach 2:
The control apparatus acts as an intermediary between the contact detection sensor and the robot's motion control. Rather than directly stopping the robot upon contact detection, the control system mediates the response based on the current mode, allowing teaching operations to continue in teaching mode while still providing safety monitoring.
3Object-affected harmful factors
If the operation position for opening the hand is set close to the work table, then workpiece damage is prevented, but the risk of contact with the work table increases
Solution Approach 1:
The system dynamically adjusts the hand opening position and retreat behavior based on the operational mode. In teaching mode, the robot can operate at positions close to the work table with modified contact response. In playback mode, the system restores stricter safety margins and automatic retreat functionality. This allows the robot to achieve close positioning for workpiece safety while maintaining contact avoidance through mode-dependent control.
Solution Approach 2:
The control apparatus changes operational parameters such as the hand opening position, retreat threshold, and contact response level based on the current mode. In teaching mode, parameters are adjusted to allow closer operation to the work table. In playback mode, parameters are restored to prioritize contact avoidance. This parameter switching resolves the contradiction between workpiece protection and contact avoidance.
Data Source
AI summary
A robot control apparatus comprises a contact detection unit which judges whether or not a robot is in contact with an object other than the robot, and an operation direction monitor unit which detects an operation direction of the robot after the robot comes in contact with the object and monitors operation of the robot. After the robot comes in contact with the object, the operation direction monitor unit permits operation of the robot being within a permissible range and inhibits operation of the robot falling outside the permissible range.