Constrained Proxy Control for Teleoperated Follower Motion
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Solution Overview
Problem
Teleoperated devices face challenges in accurately and quickly following commands due to motion limits, kinematic constraints, and velocity/acceleration limits, leading to unintuitive and disorienting movements for operators.
Innovation Solution
Introduce a proxy constraint to limit the possible poses of a virtual leader device, allowing the follower device to follow the constrained proxy rather than the virtual leader device, thereby improving motion control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the follower device directly follows the commanded motions of the leader device, then the system maintains simple control architecture, but the follower device cannot accurately follow commands when subject to motion limits and kinematic constraints
Solution Approach 1:
The patent introduces a proxy device as an intermediary between the leader device and follower device. The proxy receives commanded motions from the leader and generates constrained motions that account for the follower's motion limits, kinematic constraints, velocity limits, and acceleration limits. This intermediary layer enables accurate motion following without requiring complex direct control of the follower device.
Solution Approach 2:
The patent creates a virtual copy (proxy) of the leader device that incorporates the follower's constraints. Instead of directly controlling the follower with complex constraint calculations, the system copies the leader's commanded motions into the proxy, applies constraints to the proxy, and uses the constrained proxy motions to control the follower. This copying approach simplifies the control architecture while maintaining accuracy.
2Speed
If the follower device operates without motion constraints, then the system responds quickly to leader device commands, but the follower device may exceed its motion limits and kinematic constraints
Solution Approach 1:
The patent applies preliminary action by pre-calculating and applying motion constraints to the proxy device before the follower executes the motions. The system determines velocity limits and acceleration limits for the proxy based on the follower's kinematic constraints and motion capabilities. This preliminary constraint application ensures the follower can execute motions quickly without exceeding its physical limits.
Solution Approach 2:
The patent implements dynamic constraint adjustment by making the proxy's motion constraints adaptive to the follower's current state. The system continuously updates velocity limits and acceleration limits based on the follower's position, orientation, and current motion capabilities. This dynamic approach maintains reliability while allowing maximum response speed within safe operating boundaries.
3Ease of operation
If the follower device follows commands without constraint adjustment, then the control system remains simple, but the operator experiences lag and disorienting movements
Solution Approach 1:
The patent implements feedback by continuously monitoring the follower's actual motion capabilities and adjusting the proxy's constrained motions accordingly. The system uses information about the follower's position, velocity, acceleration, and kinematic constraints to dynamically adjust the proxy's motion commands. This feedback loop eliminates lag and disorienting movements by ensuring the proxy always commands feasible motions, improving operator experience without requiring complex direct control algorithms.
Data Source
AI summary
Disclosed techniques include a computer-assisted device having an input control, a functional structure, and a processing system. The functional structure is configured to include a repositionable structure, and the repositionable structure is configured to support an instrument. The processing system is configured to receive a movement command from the input control, update a pose of a proxy based on the movement command and a proxy constraint, and cause the functional structure to move based on the updated pose of the proxy. In some embodiments, the input control controls a pose of a virtual leader device. The processing system updates a pose of a proxy based on the pose of the virtual leader device, updates a pose of a virtual follower device based on the updated pose of the proxy, and causes the functional structure to move based on the pose of the virtual follower device.