Overhead Cable Robot Control for Shared Workspace Collision Safety
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Solution Overview
Problem
Industrial manufacturing processes require human operators to manually interact with objects, posing safety risks due to the need for direct application of forces and potential collisions with industrial robots, which are typically confined to a defined workspace.
Innovation Solution
An overhead system utilizing a cable-connected, actively-controlled serial robot that collaborates with the operator within a shared workspace, featuring a control system with sensors and redundancy to monitor and regulate the robot's motion, ensuring safe interaction by enforcing workspace rules and responding to single-point failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an operator directly interacts with an object in the robot's workspace, then productivity and ease of operation are improved, but safety risks increase due to potential collisions with the robot
Solution Approach 1:
The system dynamically adjusts the robot's motion characteristics based on operator presence and interaction forces. The robot transitions between autonomous operation mode and collaborative operation mode, adapting its velocity, acceleration, and workspace boundaries in real-time to ensure safety while maintaining productivity during direct operator-robot collaboration
Solution Approach 2:
The control system continuously monitors operator position, robot position, interaction forces, and workspace boundaries through sensors. This feedback enables real-time detection of potential collisions and triggers appropriate safety responses, including velocity reduction, motion cessation, or emergency stop, allowing safe direct interaction while maintaining operational efficiency
2Object-affected harmful factors
If the operator works outside the robot's workspace, then safety is improved, but productivity and ease of operation deteriorate due to increased distance from the work object
Solution Approach 1:
The system dynamically expands the robot's collaborative workspace boundaries when an operator is detected, allowing the operator to work within the shared workspace rather than being confined to areas outside the robot's reach. This dynamic workspace adaptation enables direct manipulation of work objects while maintaining safety through real-time motion coordination
Solution Approach 2:
The control system acts as an intermediary between the operator and robot, mediating their interactions within the shared workspace. It coordinates their motions, manages force interactions, and ensures that both can operate safely in proximity to the same work objects, eliminating the need for the operator to work at a distance
3Reliability
If redundant monitoring systems are implemented, then reliability is improved through fault detection, but device complexity increases
Solution Approach 1:
The control system performs multiple functions simultaneously: it manages robot motion control, monitors operator position, detects collisions, enforces workspace boundaries, and handles emergency stops. By consolidating these safety and control functions into a single integrated system rather than separate redundant systems, the patent achieves high reliability without proportionally increasing complexity
Data Source
AI summary
An overhead system assists an operator in moving an object when the operator imparts a manual force to the object in a shared workspace characterized by overlapping ranges of motion of the robot and operator. The system includes an articulated serial robot, a cable, sensors, and a control system. One end of the cable connects to a distal end link of the robot. Another end of the cable connects to the object to suspend the object. The sensors measure a cable force and/or angle. The control system regulates operation of the robot by translating vertically and horizontally in response to the cable force and/or angle. The control system limits the position and/or velocity of the end link according to corresponding work space rules, including respective position and velocity limits, such that the system is immune to a single-point failure.