Robot Safety Control During Direct Teaching via Distance Monitoring
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Solution Overview
Problem
Current methods for programming industrial manipulators are complex and inefficient, especially for small and medium-sized batches, and direct teaching programming poses safety risks due to high proximity between operators and robots, limiting speed and flexibility in applications like spraying and welding.
Innovation Solution
A method for safety control during direct teaching of a robotized system using a force/torque sensor and admittance control, which monitors relative distance and speed between robot links and the operator, stopping the robot if safety thresholds are exceeded, allowing high-speed trajectory recording while ensuring operator safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct teaching programming is used to simplify robot programming, then ease of operation is improved, but safety risks increase due to high proximity between operators and robots
Solution Approach 1:
The system dynamically adjusts robot speed based on real-time operator position and proximity. During direct teaching, the robot operates at high speed when the operator is outside the safety zone, and automatically reduces speed when the operator enters the proximity zone, resolving the contradiction between operational simplicity and safety
Solution Approach 2:
The system continuously monitors operator position via detection means and provides real-time feedback to the control unit. This feedback loop enables the robot to adjust its speed dynamically, maintaining safety while preserving the simplicity of direct teaching programming
2Reliability
If robot speed is limited during direct teaching to ensure safety, then operator safety is improved, but productivity decreases due to slower trajectory recording
Solution Approach 1:
The robot speed is dynamically adjusted rather than uniformly limited. When the operator is outside the proximity zone, the robot maintains high speed for efficient trajectory recording. When the operator enters the zone, speed is reduced only temporarily until the operator exits, minimizing impact on overall productivity while ensuring safety
3Manufacturing precision
If traditional point-to-point programming is used, then manufacturing precision is improved, but ease of operation deteriorates due to complex programming requirements
Solution Approach 1:
The system records the operator's manual guidance trajectory and creates a digital copy that can be replayed with high precision. This copying approach preserves the simplicity of manual guidance while achieving the positioning accuracy of traditional programming methods
Data Source
AI summary
A method for the safety control, through direct teaching, of a robotised system comprises a learning step, wherein a processing unit determines a relative distance (RD) between at least one link (L) of the robot manipulator and an operator (O) and controls whether the relative distance (RD) of the at least one link (L) exceeds a predefined distance threshold value (TV); wherein the predefined distance threshold value (TV) is equal to or greater than the distance covered by the robot manipulator in the amount of time needed to stop starting from a respective maximum linear speed (VMAX); in case the relative distance (RD) is smaller than the predefined distance threshold value (TV), the method entails stopping the robot.