Geared Haptic Linkage for Wide Motion Without Hand Collisions
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Solution Overview
Problem
Existing haptic devices often restrict the user's hand movement due to a cage-like structure, leading to collisions and reduced range of motion.
Innovation Solution
A haptic device with a linkage system providing three rotational degrees of freedom, featuring pivot arms and gear devices that allow for a large range of motion without enclosing the user's hand, reducing the risk of collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a wrist structure with linkage and angled profiles is used to provide three rotational degrees of freedom, then the device can detect orientation and provide force feedback, but the structure surrounds the user's hand in a cage-like manner that limits range of motion and causes collisions
Solution Approach 1:
The first pivot arm is divided into two separate arm segments that are coupled by a first gear device. This segmentation allows the arm segments to move independently while maintaining the rotational degrees of freedom, thereby reducing the cage-like enclosure and minimizing collisions with the user's hand.
Solution Approach 2:
A gear device is introduced as an intermediary mechanism between the arm segments. The gear device transmits motion between the arm segments while allowing them to move in different directions, enabling greater range of motion without requiring a rigid cage-like structure.
2Reliability
If a parallel kinematic structure with angled profiles is used to provide translational degrees of freedom, then the device can provide force feedback, but the handle and wrist structure collide with surrounding structures or between devices
Solution Approach 1:
The pivot arms are segmented into multiple arm segments coupled by gear devices. This segmentation allows the structure to provide force feedback through controlled motion while reducing the risk of collisions with surrounding structures by enabling more flexible movement paths.
Solution Approach 2:
The gear devices change the motion parameters between arm segments, allowing the device to maintain force feedback capability while altering the trajectory and range of motion to avoid collisions with surrounding structures.
Data Source
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AI summary
The present invention provides a haptic device (10) comprising a handle (1), a base structure (2), and a linkage consisting of two pivotally connected pivot arms (11, 12), wherein the first pivot arm (11) is pivotally connected to the base structure (2) and the second pivot arm (12) is pivotally connected to the handle (1). The pivot axes (A, B, C) intersect at a common center of rotation (Z). The first pivot arm (11) has two pivotally connected arm segments (3, 4), wherein the first pivot joint (7) is present on the first arm segment (3), which is coupled to the second arm segment (4) by a first gear device (13) such that an arm end section (4b) of the second arm segment (4) is moved on a first circular path (K1) about a virtual first axis that is orthogonal to the first pivot axis (A).The second pivot arm (12) has two pivotally connected arm segments (5, 6), with the second pivot joint (8) being located at the arm end portion (4b) of the second arm segment (4) and the third arm segment (5), and the third pivot joint (9) being located at an arm end portion (6b) of the fourth arm segment (6). The third and fourth arm segments (5, 6) are coupled by a second gear device (13) such that the arm end portion (6b) of the fourth arm segment (6) is moved on a second circular path (K2) about a virtual second axis that is orthogonal to the second pivot axis (B).