Haptic Fingerstall with Dynamic Contact Point Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-finger haptic devices can only feed back translation force to fingertips, making it difficult to provide a grasping sense to multiple fingers effectively, and mechanisms with fixed contact points lead to odd feelings and fatigue due to inadequate reflection of contact point changes.
Innovation Solution
A force/tactile feedback device with a 3-degree-of-freedom position feedback arm, a 3-degree-of-freedom gimbal mechanism, and a 1-degree-of-freedom contact point feedback arm, reducing active degrees of freedom per finger unit to simplify design and prevent unnecessary moment generation, allowing for precise feedback of contact point positions and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a multi-finger haptic device feeds back translation force to fingertips, then force feedback capability is improved, but the ability to provide grasping sense to multiple fingers is insufficient
Solution Approach 1:
The device divides the force feedback system into separate finger units, with each finger having its own actuator and feedback mechanism. This segmentation allows independent control and feedback for each finger, enabling realistic grasping sense while maintaining overall force feedback capability.
Solution Approach 2:
The patent introduces a fingerstall as an intermediary component between the actuator and the fingertip. The fingerstall transmits force from the actuator to the fingertip while allowing the contact point to move naturally, thereby providing both force feedback and realistic grasping sensation.
2Device complexity
If the contact point is fixed in the feedback mechanism, then the mechanism is simplified, but it causes odd feelings and fatigue due to inadequate reflection of contact point changes
Solution Approach 1:
The patent transforms the fixed contact point into a dynamic one that can move along the fingerstall. The contact point position is fed back to the actuator, allowing the system to adapt to natural finger movements and maintain comfortable operation without causing odd feelings or fatigue.
Solution Approach 2:
The device implements a feedback loop where the contact point position is detected and fed back to the actuator control system. This feedback mechanism allows the system to automatically adjust to maintain the contact point at the appropriate position, eliminating odd feelings and reducing operator fatigue while keeping the mechanism relatively simple.
3Measurement precision
If actuators are arranged at all axes to feed back force and moment, then force feedback accuracy is improved, but the device becomes mechanically complicated and heavy
Solution Approach 1:
The patent extracts the moment feedback function from the traditional six-degree-of-freedom actuator arrangement. By using the fingerstall geometry and the natural rotation of the finger, the system achieves moment feedback without requiring additional actuators at each axis, thereby reducing mechanical complexity and weight while maintaining force feedback accuracy.
Solution Approach 2:
The patent replaces some mechanical actuators with a hybrid system that uses the fingerstall structure and feedback control to achieve force and moment feedback. This substitution reduces the number of mechanical components and simplifies the overall system while maintaining the required feedback accuracy.
4Device complexity
If a 3-degree-of-freedom arm with fixed contact point is used, then the structure is simplified, but it cannot reflect contact point changes and causes unnecessary moment generation
Solution Approach 1:
The patent introduces dynamic movement capability to the contact point within the fingerstall, allowing it to move along the feedback arm. This dynamic adjustment enables the system to accommodate finger orientation changes without generating unnecessary moments, while maintaining the overall structural simplicity of the 3-degree-of-freedom arm configuration.
Solution Approach 2:
The system changes the position parameter of the contact point dynamically based on finger orientation and contact state. By adjusting the contact point position along the feedback arm, the system eliminates unnecessary moment generation while preserving the simple 3-degree-of-freedom structure.
Data Source
AI summary
A force/tactile feedback device feeding back a force sense to a fingertip of an operator includes a fingerstall to which the fingertip of the operator is inserted, a position feedback means for feeding back a position to the fingertip held by the fingerstall, a fingertip contact point feedback means for feeding back a fingertip contact point to the fingertip held by the fingerstall and an unnecessary moment removal means for supporting the fingertip contact point feedback means so that unnecessary moment is not generated at a tip portion of the position feedback means.