Variable Virtual Fixtures for Undisrupted Teleoperation Workflow Coupling

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Solution Overview

Problem

Existing cobot systems face challenges in integrating seamless workflow integration and ensuring safety in complex and dynamic human-robot interaction scenarios, particularly in biomedical laboratories, where human intervention disrupts automated processes.

Innovation Solution

A solution based on variable virtual fixtures that divide workflows into manual and automated phases, using teleoperation with a main and subordinate robot, calculate control torques, and apply guiding forces via a virtual fixture that adapts its shape to workflow stages, ensuring non-interference coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If human operators are introduced into automated laboratory processes, then flexibility and human intervention capability are improved, but task execution continuity is disrupted

Engineering Contradiction:

Improvehuman intervention capabilityVSAvoidtask execution continuity

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent introduces a virtual fixture as an intermediary between the human operator and the robotic system. This virtual fixture provides force feedback and guidance constraints that enable seamless human-robot collaboration without disrupting workflow continuity. The virtual fixture acts as a mediator that translates human intent into robot actions while maintaining automated process flow.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent dynamically adjusts virtual fixture parameters (such as stiffness, damping, and constraint forces) based on the operational phase and human input. By changing these parameters in real-time, the system adapts to human intervention needs while maintaining task execution continuity, resolving the contradiction between flexibility and productivity.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If machine learning algorithms are used for intent recognition in human-robot interaction, then interaction intelligence is improved, but computational resource consumption increases

Engineering Contradiction:

Improveinteraction intelligenceVSAvoidcomputational resource consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces complex machine learning-based intent recognition with a physics-based virtual fixture model that uses force feedback and constraint mechanics. Instead of computationally intensive algorithms, the system uses mechanical analogies (springs, dampers, constraints) to interpret and respond to human intent, significantly reducing computational resource consumption while maintaining interaction intelligence.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The virtual fixture system automatically adapts to human operator behavior through real-time force feedback and constraint adjustment without requiring explicit machine learning training. The system serves itself by using physical interaction dynamics to infer intent, eliminating the need for heavy computational resources.

Inventive Principle:

Principle #25Self-service

3Device complexity

If a fixed virtual fixture is used in teleoperation, then system simplicity is maintained, but adaptability to different operation stages is reduced

Engineering Contradiction:

Improvesystem simplicityVSAvoidadaptability to operation stages

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static virtual fixture into a dynamic one that automatically adjusts its constraints and force feedback characteristics based on the operational phase. The virtual fixture transitions between different constraint modes (e.g., position constraints during alignment, force constraints during insertion) to match the specific requirements of each operation stage, maintaining simplicity while enhancing adaptability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent divides the operation into distinct phases (alignment phase and insertion phase) with different virtual fixture configurations. By segmenting the operational requirements, the system can apply simplified, phase-specific virtual fixture parameters rather than a single complex configuration, balancing simplicity and adaptability.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20260102924A1Solution of undisrupted human-machine workflow coupling based on variable virtual fixtures

Publication Date: 2026.04.16 ZHEJIANG UNIV

AI summary

The invention discloses a method of undisrupted human-machine workflow coupling, including S1, dividing a workflow in a laboratory into manual operations and automated workflows; S2, calculating control torque of a main robot and the subordinate robot in the teleoperation system. While the subordinate robot tracks the trajectory of the main robot, the interaction torque between the subordinate robot and the environment is transmitted to the main robot. S3, setting a variable shape virtual fixture; S4, calculating the torque applied by the virtual fixture; S5, introducing the torque of the virtual fixture into the teleoperation system to realize the non-interference coupling in the human-machine workflow. The method provided by the invention facilitates manual operations to be integrated into a non-interfering and undisrupted automatic workflow, and avoids unsafe human contact with a robotic environment, while ensuring intuitive human-computer interaction performance and safety of the system.