Teleoperated Robot Manipulator Constraint Feedback for Low-Latency Control
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Solution Overview
Problem
Latency in teleoperation systems causes delays between operator commands and robot actions, leading to reduced control precision and responsiveness, and affects the feedback loop, making it challenging to provide real-time sensory information for accurate and safe operation.
Innovation Solution
Implementing a constraint engine that initiates constraining feedback commands directly to the teleoperator, enabling simultaneous constraint application to both the robot and the operator interface, and allowing relaxation of constraints by the teleoperator, along with a hybrid network topology for critical low-latency communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional teleoperation feedback loops are used, then real-time sensory information can be provided, but latency causes delays between operator commands and robot actions, reducing control precision and responsiveness
Solution Approach 1:
The system segments the feedback loop into two independent parallel paths: one for constraint enforcement (computing constraint forces and applying them immediately) and one for sensory feedback (providing real-time tactile information). This segmentation allows constraint processing to occur without blocking the real-time feedback path, reducing latency while maintaining control precision.
Solution Approach 2:
The constraint engine pre-computes constraint forces and prepares inhibition signals before they are needed, based on predicted robot states and operator commands. This preliminary action allows the system to respond immediately when constraints are violated, reducing the effective latency between command and response.
2Reliability
If constraints are applied to prevent collisions and ensure safe operation, then safety is improved, but control responsiveness and speed may be reduced
Solution Approach 1:
The system implements continuous feedback from the constraint engine to both the robot controller and operator interface. When constraints are violated, immediate feedback triggers inhibition signals that prevent unsafe actions. This real-time feedback ensures safety without requiring pre-cautious slowing, as the system can respond instantly to constraint violations.
Solution Approach 2:
The constraint engine acts as an intermediary between the operator interface and robot controller, processing commands and sensory feedback through constraint checks. This intermediary layer enforces safety constraints while maintaining the speed of communication, as it operates in parallel rather than creating sequential bottlenecks.
3Measurement precision
If haptic feedback is provided to enhance user interaction and precision, then control precision and situational awareness are improved, but cognitive load increases and system complexity grows
Solution Approach 1:
The system merges constraint enforcement and sensory feedback into a unified haptic feedback mechanism. The constraint forces computed by the constraint engine are directly integrated into the haptic feedback provided to the operator through the operator interface. This merging allows the system to communicate both safety constraints and environmental feedback through the same channel, reducing overall system complexity while maintaining control precision.
4Reliability
If constraint enforcement is implemented to prevent collisions, then safety is improved, but operator autonomy and flexibility may be reduced
Solution Approach 1:
The constraint engine dynamically adjusts constraint forces based on the current system state, robot configuration, and operator commands. Rather than applying fixed restrictive limits, the constraints are computed in real-time to be permissive when safe and restrictive when necessary. This dynamic approach maintains operator autonomy while ensuring safety, as operators experience minimal constraint enforcement unless actually approaching unsafe conditions.
Data Source
AI summary
An embodiment provides an implementation of constraints on a teleoperated system applied directly to the teleoperated robot. In conventional systems, the teleoperating operator receives feedback from the response of the teleoperated robot to the constraint. In the embodiment, however, the constraint engine initiates constraining feedback commands to the teleoperator simultaneously with its commands to the teleoperated robot. This solves a problem of latency in feedback to the operator by (a) eliminating the time taken for the robot to physically react to the constraints which is what would ordinarily trigger feedback to the teleoperator and (b) by cutting at least one step in the communication path, going directly from the constraint engine to the teleoperator instead of conventional systems that go from the constraint engine to the robot to the teleoperator. Other embodiments are described herein.