Flexible Cable Simulation via Control Point Segmentation
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Solution Overview
Problem
Current solutions fail to adequately simulate the motion of flexible retraction cables cooperating with retraction systems on robots, leading to high computational complexity and resource requirements.
Innovation Solution
A method is developed to simulate flexible cables attached to robots with retraction systems by modeling only the external part of the cable as a sequence of control points, with the retracted part considered as a 'black box, reducing the number of control points and computational effort, and using a fixed number of control points along the external part's length, which varies based on the retraction force and external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physics-based solver is used to simulate flexible cable motion in real-time, then simulation accuracy is improved, but computational time and memory usage increase significantly
Solution Approach 1:
The cable is divided into discrete segments or control points along its length, allowing the simulation to focus computational resources on key portions of the cable rather than treating it as a continuous physical object. This segmentation enables real-time simulation while maintaining visual accuracy.
Solution Approach 2:
The retraction system is extracted and treated as a separate black box component, removing it from the detailed physics simulation. Only the external part of the cable connected to the retraction system is simulated, while the retracted portion is handled through simplified constraints, significantly reducing computational complexity.
2Reliability
If fully-integrated contact and clash detection is implemented for cables, then simulation reliability is improved, but device complexity increases
Solution Approach 1:
A constraint-based intermediary mechanism is introduced to handle cable-retraction system interactions. Instead of implementing full physics-based contact detection between cable segments and the retraction system, simplified constraints act as intermediaries to enforce cable length limits and prevent unrealistic behavior, reducing system complexity while maintaining reliability.
3Manufacturing precision
If stress and strain calculations are performed for multiple cables, then manufacturing precision is improved, but use of energy increases
Solution Approach 1:
Stress and strain calculations are performed partially - only for the external portion of the cable that is visible and connected to the retraction system, rather than for the entire cable length. This partial action approach provides sufficient information for manufacturing decisions while consuming less computational energy.
Data Source
AI summary
Systems and a method for simulating a flexible retraction cable during motion of an object to which the cable is attached. The method includes receiving information inputs, including a numerical model of the object, receiving cable information inputs and retraction system information inputs. A numerical model of the flexible cable is modeled by modelling only a part of the flexible cable located outside a retraction system as a sequence of control points distributed along a length of the part, wherein each of the control points is submitted to a force representing the interaction of the control point with its environment and wherein the number of control points is fixed. The method further includes storing the numerical model of the flexible cable in a memory and simulating a motion of the flexible cable that would occur during a movement of the object.