Soft Decoupling VR Locomotion via Passive Gravity Return

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Solution Overview

Problem

Conventional omnidirectional locomotion devices for virtual reality systems are complex, expensive, and often impractical for home use due to size and stability issues, failing to provide a natural walking experience and adequate immersion.

Innovation Solution

A system comprising a platform with adjustable struts, a support halo, and a harness with sleds that allows users to move freely while decoupling their direction of movement from their gaze, utilizing sensors like IMUs to translate physical movements into virtual environment inputs, enabling natural gait and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If motorized locomotion devices use sensors and motors to counter user movements, then the user can be brought back to the center of the platform, but the device becomes complex, expensive, and prone to latency and feedback errors

Engineering Contradiction:
Improveuser position controlVSAvoidmotorized components and feedback loops
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the motorized feedback system entirely, extracting the complex control loop from the locomotion device. Instead of using motors to actively counter user movements, the system relies on passive physical constraints and gravity to return the user to the center, eliminating sensors, motors, and feedback processing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The user's own body weight and gravity serve the function of returning the user to the center of the platform. The passive ball bearing system allows the user to naturally return to the center through gravity-driven movement, eliminating the need for active motorized control and feedback mechanisms.

Inventive Principle:
Principle #25Self-service

2Reliability

If the platform is made large to prevent users from walking off, then user safety is improved, but the device becomes too large for residential rooms and difficult to store

Engineering Contradiction:
Improveuser safetyVSAvoidplatform size
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces the motorized active control system with a passive mechanical system using ball bearings and gravity. This substitution allows for a much smaller platform footprint while maintaining user safety through physical constraints and natural gravitational return, making the device suitable for residential spaces.

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

3Ease of operation

If omnidirectional ball bearing platforms are used to allow free movement, then the user can walk in 360 degrees, but the user experiences instability similar to walking on ice and loses natural gait

Engineering Contradiction:
Improveomnidirectional movementVSAvoiduser balance and gait
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies different friction characteristics to different parts of the platform. The radial direction (inward toward center) has low friction to allow free omnidirectional movement, while the tangential direction has high friction through the passive ball bearing constraint to provide stability and prevent excessive outward movement, creating a balanced experience.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a cost-effective, compact, and stable omnidirectional locomotion system that enhances user immersion in virtual environments by allowing natural movement and decoupling of movement direction from gaze, improving the overall VR experience.

Implementation Method 1

sleds moveably coupled to the support halo

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3804825B1System and method of soft decoupling an input
Publication Date: 2023.11.15 VIRTUIX HOLDINGS INC
  • EP3804825B1 patent drawingFigure 1
  • EP3804825B1 patent drawingFigure 2A~2B
  • EP3804825B1 patent drawingFigure 3

AI summary

In a virtual reality environment a user's movements are coupled, meaning the user cannot walk and look in different directions. Discloses are methods and systems for soft decoupling the movements of the user in a virtual reality environment, enabling the user to look and walk in different directions simulating real-world interactions. The soft decoupling is performed by receiving acceleration and orientation data from sensors attached to the user. A heading and a heading delta based on a ratio are calculated. The calculated heading and a velocity are translated into soft decoupling inputs for the virtual reality environment.