Nested 2-DOF Haptic Interface for Directional Guidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing haptic interfaces with two degrees of freedom are too large for integration into portable or mobile systems, and they fail to effectively guide the user's movement in privileged directions.
Innovation Solution
A haptic interface structure with two degrees of rotation freedom, featuring nested pivotal joints with magnetorheological fluid brakes, which allows independent control of the effector in both directions and reduces size through a membrane confinement system that minimizes friction and provides a recall function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two separate pivot joints with magnetorheological brakes are used to achieve two degrees of freedom, then haptic guidance in preferred directions is enabled, but the device footprint becomes too large for portable systems
Solution Approach 1:
The patent implements nested pivot joints where the first pivot joint is received within the second pivot joint, allowing both joints to occupy the same spatial envelope. This nesting arrangement enables two degrees of freedom with haptic guidance while dramatically reducing the device footprint to make it suitable for portable and mobile systems.
Solution Approach 2:
The patent transitions from a planar arrangement of separate brakes to a three-dimensional nested configuration. By stacking the pivot joints in the radial direction rather than placing them side-by-side, the invention achieves two degrees of freedom without increasing the overall footprint, effectively utilizing the third dimension to resolve the space conflict.
2Reliability
If O-rings are used to seal the magnetorheological fluid between the spheres, then fluid containment is achieved, but friction increases and effector movement transparency is reduced
Solution Approach 1:
The patent replaces traditional O-ring seals with a flexible membrane that contains the magnetorheological fluid. This membrane configuration provides adequate sealing while presenting less mechanical interference to the spherical elements, thereby reducing friction and improving the transparency of effector movement during operation.
3Reliability
If passive brakes are used to generate resistive force, then haptic feedback is provided, but the user cannot be guided in preferred directions
Solution Approach 1:
The patent divides the braking function into two independent passive brakes, each associated with a specific pivot joint and axis. This segmentation allows each brake to independently control resistive force in its respective direction, enabling the system to guide the user in preferred directions by selectively applying braking forces while maintaining reliable haptic feedback.
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 structure enables improved guidance of the effector, reduces size for portable integration, and provides a robust and efficient haptic feedback system with precise control over movement patterns.
Implementation Method 1
Each brake uses, for example, a magnetorheological fluid
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
Structure for a haptic interface with two degrees of freedom, comprising an effector (4) to be manipulated by the user and two pivot joints (P1, P2) allowing movement about two axes (X, Y) and to which the effector (4) is connected, each of the two pivot joints (P1, P2) comprising spherical elements (S1, S2, S3) nested inside one another and forming passive brakes about each of their axes (X, Y).