Omnidirectional Haptic Mobile Platform for Singularity-Free Interaction

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Solution Overview

Problem

Existing haptic devices are limited in their ability to follow desired trajectories, require support structures with stiff links, and suffer from kinematic singularities, making them cumbersome and less effective for continuous interaction and rehabilitation applications.

Innovation Solution

A haptic device with a mobile unit featuring three wheels, each with a wheel motor unit and sliding means allowing free movement transverse to the rotation plane, enabling omni-directional movement and continuous interaction without kinematic singularities, combined with a control system using a Kalman filter for precise position tracking and force feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional haptic devices use stiff links and kinematical closed chains, then structural stability is improved, but device complexity and ease of operation deteriorate due to kinematic singularities and support structure requirements

Engineering Contradiction:
Improvestructural stabilityVSAvoiddevice complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical system of stiff links and kinematical closed chains with a mobile robotic platform equipped with force feedback actuators. This substitution eliminates the need for complex kinematical chains while maintaining structural stability through active control and force feedback mechanisms, thereby reducing device complexity without sacrificing stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention transitions from static stiff link structures to a dynamic mobile platform that can adapt its configuration and movement. The mobile unit with force feedback capabilities provides dynamic stability control, allowing the system to maintain structural integrity while avoiding kinematic singularities through active motion planning and control algorithms.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If haptic devices follow predetermined paths with traditional mechanisms, then manufacturing precision is improved, but ease of operation deteriorates due to kinematic constraints and friction

Engineering Contradiction:
Improvetrajectory accuracyVSAvoidease of operation
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces traditional mechanical path-following mechanisms with a mobile robotic platform that uses force feedback control and software-based trajectory tracking. This substitution eliminates mechanical friction and kinematic constraints, allowing the system to achieve high trajectory accuracy through control algorithms while significantly improving ease of operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the control parameters from mechanical constraint-based control to force feedback-based control with Kalman filter optimization. This allows the system to achieve precise trajectory following by dynamically adjusting control parameters rather than relying on fixed mechanical constraints, thereby improving both accuracy and ease of operation.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If haptic devices use indirect force control without explicit force feedback ring closure, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvecontrol system complexityVSAvoidforce feedback precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces indirect force control methods with a mobile platform equipped with explicit force feedback control and Kalman filter-based measurement fusion. This substitution maintains relatively simple device architecture while achieving high force feedback precision through advanced control algorithms and sensor fusion techniques.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention implements explicit force feedback ring closure with Kalman filter-based sensor fusion to achieve precise force measurement and control. The feedback mechanism integrates multiple sensor inputs optimally, providing high measurement precision while maintaining manageable system complexity through modular control architecture.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2678759B1Haptic system and device for man-machine interaction
Publication Date: 2025.10.22 HUMANWARE
  • EP2678759B1 patent drawingFigure 1
  • EP2678759B1 patent drawingFigure 1A
  • EP2678759B1 patent drawingFigure 1B

AI summary

A haptic device (100) configured to be used as man-machine interface for interactions in virtual and/or real places, tele-operation and rehabilitation assisted by robot comprises a mobile unit (1) configured to be interfaced with at least one user (3), a control unit (4) associated with the mobile unit (1 ) and a feeding unit (10). In particular, the mobile unit (1 ) comprises at least three wheels (13) rotationally spaced from each other; each wheels (13) comprises a rotation axis (13') and has a wheel motor unit (1 1) independent, such that each wheel motor unit (1 1) allows the rotation of each wheel (13) about the respective rotation axis (13') in a rotation plane orthogonal to the rotation axis (13'). In addition, each wheel (13) has sliding means (21 ) in a direction transversal to the rotation support plane, such that the mobile unit (1 ) can follow any trajectory. In particular, the sliding means comprises a plurality of rollers (21) arranged adjacent to each other on a same row. This way, each wheel (13) can carry out a "leeway motion" transversally to each wheel rotation plane by the resulting rolling applied by the respective motor units (1 1 ) to the other wheels (13). In particular, in case of three wheels (13) of the mobile unit (1), if a first wheel it has not momentarily a rolling movement, giving to the other two wheels (13) an identical rolling speed, is obtained a translating the first wheel orthogonally to each wheel rotation plane i.e. parallel to its own rotation axis (13'). Giving instead different speeds to the other two wheels (13), it is possible to obtain a movement in a direction oblique with respect to the rotation plane of the first wheel.