Dual-Proxy Haptic Robot Control Under Long Communication Delays
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Solution Overview
Problem
Haptic teleoperation systems face challenges such as inaccurate dynamic modeling, sensor noises, task uncertainties, human-in-the-loop disturbances, communication time delays, and non-collocation, which affect haptic transparency and stability.
Innovation Solution
The implementation of a local autonomy-based haptic-robot control paradigm using a dual-proxy model, which divides the global bilateral loop into three independent blocks: local haptic and robot controllers, and a smart dual-proxy model for high-level information exchange, ensuring safe and consistent command inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a global bilateral feedback loop is used for haptic teleoperation, then haptic transparency can be achieved, but system stability deteriorates due to communication time delays and non-collocation
Solution Approach 1:
The patent segments the global bilateral feedback loop into three independent local control loops (haptic device side, robot side, and dual-proxy model side). Each local loop operates autonomously with its own controller, eliminating the stability issues caused by communication delays in a global feedback loop while maintaining haptic transparency through coordinated operation of the segmented loops.
Solution Approach 2:
The dual-proxy model acts as an intermediary between the haptic device side and robot side, exchanging high-level information and generating safe, consistent command inputs. This intermediary approach allows the system to maintain transparency while avoiding direct coupling that would cause stability problems under communication delays.
2Speed
If communication time delays are reduced to maintain stability, then system responsiveness improves, but the ability to operate over long distances deteriorates
Solution Approach 1:
By segmenting the control architecture into independent local loops, the system eliminates the direct coupling that would require low latency communication. Each local loop operates autonomously at its own speed, allowing the haptic device and robot to be located far apart without compromising stability or responsiveness.
Solution Approach 2:
Each local control loop serves itself autonomously with local controllers that do not depend on real-time feedback from remote components. The haptic device side and robot side each maintain their own stability and performance independently, enabling long-distance operation without communication delay constraints.
3Stability of the object's composition
If local autonomy-based control with dual-proxy model is implemented, then system stability improves under communication delays, but device complexity increases
Solution Approach 1:
While segmentation into multiple local loops increases architectural complexity, it simplifies the control logic within each loop by eliminating the need to compensate for communication delays and non-collocation effects. The dual-proxy model provides a standardized interface that manages the complexity of coordinating multiple independent loops.
Data Source
AI summary
Haptic-robot control based on local autonomy and a dual-proxy model is provided. The dual proxy guarantees generation of safe and consistent commands for two local controllers, which ensure the compliance and stability of the systems on both sides. A Force-Space Particle Filter enables an autonomous modeling and rendering of the task contact geometry from the robot state and sensory data. The method suppresses the instability issues caused by the transfer of power variables through a network with communication delays in conventional haptic-robot controllers. The results demonstrated the transparency and high fidelity of the method, and robustness to communication delays. While the conventional method failed for communication delays higher that milliseconds, the dual proxy method maintained high performance for delays up to one and a half seconds. The local autonomy-based haptic control of robots with the dual-proxy model enables applications in areas such as medical, underwater and space robotics.