Multi-arm Robot Collision Avoidance via Dynamic Automatic Zones
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Solution Overview
Problem
Existing systems fail to effectively prevent collisions between multiple robots in a manufacturing environment, particularly due to difficulties in specifying interference spaces in a fixed coordinate system, leading to increased downtime and computational inefficiencies in three-dimensional collision detection.
Innovation Solution
A system and method for controlling motion interference avoidance in a workcell, utilizing a sequence of instructions that includes an interference check automatic zone method, where robots are represented as voxel models to determine overlapping spaces and adjust their paths in real-time to avoid collisions, allowing for three-dimensional collision detection and reservation of programmed trajectories without collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art systems use fixed coordinate system interference spaces to prevent collisions, then collision prevention is achieved, but working cycle time increases due to wait-and-move process
Solution Approach 1:
The system transitions from static interference spaces defined in fixed coordinate systems to dynamic automatic zones that are calculated based on actual robot motion paths and speeds. Each robot's automatic zone is continuously updated as it moves, allowing other robots to utilize spaces that are not currently occupied, thereby eliminating the wait-and-move process while maintaining collision prevention.
Solution Approach 2:
The system pre-calculates automatic zones based on programmed motion paths before execution, and continuously updates them during operation. This preliminary preparation of spatial information allows robots to move proactively rather than reactively waiting for space availability, reducing idle time while ensuring safety.
2Measurement precision
If prior art systems model robots as spheres and cylinders for collision detection, then real-time collision detection is achieved, but computational cost grows exponentially with number of robots and elements
Solution Approach 1:
The system segments the workspace into discrete volumetric elements (voxels) and represents each robot's automatic zone as a collection of occupied voxels along its motion path. This segmentation transforms the complex continuous collision detection problem into discrete voxel comparisons, reducing computational complexity from exponential to manageable levels while maintaining accurate three-dimensional collision detection.
Solution Approach 2:
Instead of performing complex geometric calculations with spherical and cylindrical models, the system creates simplified voxel-based copies of robot occupancy spaces. These voxel representations capture the essential spatial information needed for collision detection without the computational burden of continuous geometric modeling, enabling efficient real-time comparisons.
3Measurement precision
If prior art systems perform frequent element-by-element comparison of robot models in real-time, then impending collision detection is achieved, but automated operation must cease and robots must stop
Solution Approach 1:
The system pre-calculates automatic zones based on programmed motion paths before execution begins. During real-time operation, it only needs to compare pre-computed voxel representations of robot zones rather than performing frequent element-by-element geometric comparisons. This preliminary preparation enables continuous automated operation with minimal interruptions.
Solution Approach 2:
The automatic zones are dynamically updated during robot motion based on actual positions and velocities, allowing the system to adapt to changing conditions while maintaining efficient voxel-based comparisons. This dynamic approach enables the system to detect potential collisions and make minor trajectory adjustments without stopping automated operation, unlike static approaches that require complete halts.
4Reliability
If prior art systems use I/O handshaking mechanism for interference avoidance, then collision prevention is achieved, but configuration of multiple robot arms becomes complex
Solution Approach 1:
The system automatically calculates and manages interference zones for each robot based on their programmed motion paths and spatial relationships. Instead of requiring manual configuration of interference spaces or complex I/O handshaking protocols between controllers, the system self-generates the necessary spatial information and coordination logic, greatly simplifying configuration while maintaining reliable collision prevention.
Data Source
AI summary
A system and method for controlling avoiding collisions in a workcell containing multiple robots is provided. The system includes a sequence of instructions residing on a controller for execution thereon to perform an interference check automatic zone method. The interference check automatic zone method includes the steps of: determining a first portion of a common space that is occupied during a movement of a first robot along a first programmed path; determining a second portion of the common space that is occupied during a movement of a second robot along a second programmed path; comparing the first portion and the second portion to determine if an overlap exists therebetween; and moving the first robot and the second robot in response to whether or not the overlap exists.