3D Workspace Safety Monitoring Using Potential Occupancy Envelopes
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Solution Overview
Problem
Conventional industrial robots pose safety risks due to limited accuracy and dynamic modeling, especially in collaborative human-robot applications, as they lack precise control over movement trajectories and stopping distances, which can lead to unsafe interactions with humans in shared workspaces.
Innovation Solution
The development of a safety system that generates and enforces 'potential occupancy envelopes' (POEs) for both robots and humans, using 3D imaging sensors to dynamically model and visualize safe and unsafe regions, allowing for real-time adjustments to ensure safe operation by restricting robot movements based on computed POEs and defined zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional industrial robots are used in collaborative workspaces, then productivity and automation capability are improved, but safety risks increase due to limited accuracy and inability to precisely control movement trajectories and stopping distances
Solution Approach 1:
The system performs preliminary computation of potential occupancy envelopes (POEs) before robot execution of movements. The safety system computes the POE based on the robot's current state, dynamics model, and commanded movements, then uses this pre-computed envelope to determine safety before allowing the movement to proceed. This preliminary safety assessment prevents unsafe collisions while maintaining productivity.
Solution Approach 2:
The patent introduces an intermediary safety system that acts as a mediator between the robot controller and the physical workspace. This safety system includes a POE computation module that calculates potential occupancy envelopes and a safety determination module that compares the POE with the actual workspace environment to determine if movements are safe. This intermediary layer enables collaborative operation by providing real-time safety verification without requiring physical guarding.
2Reliability
If robot movements are restricted to ensure safety, then safety is improved, but productivity and workspace utilization decrease
Solution Approach 1:
The system dynamically adjusts safety restrictions based on real-time conditions. The POE computation is performed continuously as the robot executes movements, and the safety determination is updated in real-time. This dynamic approach allows the robot to operate freely within computed safe zones while imposing restrictions only where and when potential hazards exist, thereby maximizing workspace utilization while maintaining safety.
Solution Approach 2:
The safety system applies restrictions locally rather than globally. Instead of restricting the entire workspace, the system computes the POE for specific commanded movements and determines safety for those specific trajectories. This allows safe regions to be utilized fully while restricting only the specific movements that would cause hazards, thereby improving overall productivity while maintaining safety.
3Reliability
If traditional safety systems like light curtains or area sensors are used, then safety is improved, but workspace constraints and complexity increase
Solution Approach 1:
The patent replaces traditional mechanical and optical safety systems (light curtains, area sensors, physical guarding) with a computational safety system. Instead of using physical barriers or optical sensors to detect human presence, the system uses a dynamics model and POE computation to predict and verify safety. This substitution eliminates the need for complex safety hardware and reduces workspace constraints while maintaining or improving safety.
Solution Approach 2:
The system creates a computational copy or model of the robot's potential occupancy in the form of the POE. This virtual envelope represents all possible positions the robot may occupy during execution of a commanded movement, considering dynamics, inertia, and control accuracy. By working with this computational copy rather than physical safety systems, the patent simplifies the overall system while enabling collaborative operation.
Data Source
AI summary
Various embodiments for enforcing safe operation of machinery performing an activity in a three-dimensional (3D) workspace includes computationally generating a 3D spatial representation of the workspace; computationally mapping 3D regions of the workspace corresponding to space occupied by the machinery and a human; and based thereon, restricting operation of the machinery in accordance with a safety protocol during physical performance of the activity. Limited-access zones are defined within which the presence of a human will not affect operation of the machinery.