Robot Workstation Collision Simulation for Human-Safe Speed Limits
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Solution Overview
Problem
Current methods for assessing and mitigating risks in human-robot cooperation are complex, require physical systems, and rely on precise knowledge of robot dynamics, making them impractical for early planning stages and prone to reduced cycle times due to conservative collision calculations and limited measurement reproducibility.
Innovation Solution
A method that simulates robot movements using a test setup to determine collision forces and surface pressures, allowing for the determination of permissible travel speeds and assessment of hazards before system creation, incorporating tool data, workspace analysis, and simulation or measurement of axis movement profiles to ensure compliance with safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If computer models and collision measurements are used to assess risks, then safety standards can be met, but the processes become very complex and require physical systems already in place
Solution Approach 1:
The patent creates a digital twin (computer model) that replicates the physical robot system's dynamics, geometry, and control behavior. This virtual copy enables risk assessment without requiring the physical system to be present, eliminating the need for complex physical measurement setups while maintaining assessment accuracy through iterative validation against real system data.
Solution Approach 2:
The method performs risk assessment during the planning phase before the physical system is deployed. By evaluating collision risks in the virtual model beforehand, the system identifies hazardous situations and adjusts robot behavior in advance, avoiding the need for complex real-time measurement systems and enabling safety validation before hardware installation.
2Reliability
If collision risks are conservatively calculated, then safety is ensured, but robot movements must be slowed down considerably leading to reduced cycle times
Solution Approach 1:
The patent applies different safety strategies to different spatial locations and robot states. Instead of uniformly reducing speed throughout the workspace, the system identifies specific hazardous zones and critical situations where collisions pose significant risk, then applies speed restrictions only in those localized areas. This allows robot to operate at full speed in safe zones while maintaining safety in hazardous zones.
Solution Approach 2:
The method dynamically adjusts robot movement parameters (speed, acceleration) based on the virtual collision assessment results. Rather than using fixed conservative limits, the system optimizes motion parameters for each specific task and workspace configuration, achieving the minimum necessary speed restrictions to meet safety standards while maximizing productivity.
3Measurement precision
If physical measurement systems are deployed, then collision data can be collected, but measurements cannot be brought to every point in the plant due to interference contours and reproducibility is difficult
Solution Approach 1:
The patent replaces physical measurement systems with a virtual measurement capability through the digital twin. The computer model can evaluate collision risks at any position and orientation within the workspace without physical constraints. This virtual measurement approach provides complete coverage of the workspace while maintaining measurement precision through validated simulation algorithms.
Solution Approach 2:
The virtual assessment system serves multiple functions: it evaluates collision risks, optimizes robot trajectories, validates safety concepts, and supports planning decisions. This single virtual model replaces multiple specialized physical measurement devices, providing universal applicability across different workspace configurations and robot types without requiring additional hardware.
Data Source
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AI summary
The invention relates to a method for preventing collisions of a robot (12) with a cooperating worker (20), wherein the critical path points and courses posing a risk of collision, for example narrow passages or pinching or clamping points, are ascertained by means of a simulation, and collisions are simulated there by means of a pendulum (26), which simulates a worker, or a second robot (24), the variables which influence the movement of a robot (12), for example the permissible movement speeds of the robot, being ascertained from said simulation. The method has the following steps: a) providing a work task to be carried out by the robot (12) and a worker (20); b) providing a layout of a workstation (10) in which the work task is to be carried out; c) providing tool data which characterizes a tool (16) to be used when the robot (12) is carrying out the work task; d) ascertaining each axial movement pattern, which is required for carrying out the work task, of the robot (12) while taking into consideration the information provided in steps a) to c); e) providing a work area (22) of the worker (20); f) ascertaining critical path points of the robot (12) where the robot (12) exceeds a specified movement speed and/or a specified mass of an element to be moved by means of the robot (12) is exceeded; g) simulating each collision at the critical path points by means of a second robot (24); and h) determining permissible movement speeds of the robot (12) for each critical path point while taking into consideration the simulated collisions.