Limb Clamp and Rope Centering for Exoskeleton Joint Alignment
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Solution Overview
Problem
Existing exoskeleton systems face challenges in accurately aligning joints with human limbs due to varying limb diameters, leading to joint misalignment, parasitic forces, and reduced range of motion, while current solutions either require additional material or manual adjustment, compromising comfort and functionality.
Innovation Solution
A device with pivoting clamps and a support rope system that centers the limb relative to the exoskeleton by adjusting to different diameters without additional parts or tools, ensuring consistent alignment and stiffness, and minimizing parasitic forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the limb is mounted to the pHRI with a constant position of the circumference, then the mounting location is simple and consistent, but the joint misalignment increases for different limb diameters
Solution Approach 1:
The pHRI incorporates a passive compensation joint that allows dynamic adjustment of the joint axis position relative to the limb center. This dynamic mechanism automatically compensates for variations in limb diameter, maintaining accurate joint alignment across different users without requiring manual adjustment or precise manufacturing for each individual case.
Solution Approach 2:
The system changes the positional parameter of the joint axis relative to the limb surface based on the limb diameter. By allowing the joint axis position to vary dynamically rather than being fixed, the system adapts to different limb sizes while maintaining alignment accuracy.
2Manufacturing precision
If passive compensation joints are added to compensate for misalignment, then the joint alignment accuracy improves, but the controllability and observability of the human and robot arms deteriorates
Solution Approach 1:
The passive compensation joint is segmented into separate compensation mechanisms for different degrees of freedom. This segmentation allows the compensation function to be isolated from the controlled joints, maintaining controllability and observability of the primary motion while compensating for alignment errors.
3Object-affected harmful factors
If additional cushioning is used to avoid offset for small arms, then the comfort improves, but the material cost and work steps increase
Solution Approach 1:
The passive compensation joint serves itself by automatically adjusting to the limb diameter through its mechanical design. The mechanism self-regulates the joint axis position based on the limb size, eliminating the need for additional cushioning materials or manual adjustment work steps.
4Ease of manufacture
If the pHRI uses a constant footprint design, then the manufacturing is simple and consistent, but the range of motion is reduced for users with smaller limbs
Solution Approach 1:
The pHRI employs dynamic adjustment mechanisms that allow the footprint and joint axis position to adapt to different limb sizes. This dynamic capability enables the system to maintain optimal range of motion for both small and large limbs while keeping the base design standardized.
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 device provides toolless adaptation to varying limb diameters, maintaining consistent alignment and stiffness, reducing joint discomfort, and enhancing the range of motion, while being cost-effective and user-friendly.
Implementation Method 1
a support rope system comprising at least one support rope (50), with at least one support rope of the rope system being connected to a tensioning element (5) fixed with respect to the base structure (4)
Implementation Method 2
two clamps (1) with at least one pivot axis (A), the clamps (1) being configured to be pivoted around the at least one pivot axis (A)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to a device (100) for arrangement on a body (20) comprising an essentially rotation-symmetric portion, wherein the device (100) comprises at least one interface (30), the interface (30) comprising: • - two clamps (1) with at least one pivot axis (A), each clamp (1) comprising a clamp tip (2), the respective clamp tip (2) being arranged opposite of the at least one pivot axis (A) and the pivot axis (A) being arranged fixed in relation to a base structure (4) comprised by the device (100), wherein the clamps (1) are configured to be pivoted around the at least one pivot axis (A) between a first position (11) and a second position (12), respectively, wherein in the first position (11), the clamp tips (2) are spaced further from each other than in the second position (12) • - a support structure (40) arranged between the clamps (1), the support structure (40) being configured to be arranged on and/or to support the rotation-symmetric portion of the body (20) and • - a support rope system comprising at least one support rope (50), with at least one support rope (50) of the rope system being connected to a tensioning element (5) fixed with respect to the base structure (4), the connection of the tensioning element (5) and the at least one support rope (50) being spaced from the at least one pivot axis (A) and arranged on the opposite side of the clamp (1) with respect to the support structure (40), the support rope (50) further extending across a redirection means (6) provided by each of the clamps (1), the redirection means (6) having a defined distance with regard to the at least one pivot axis (A) of the respective clamp (1), and extending towards the support structure (40), wherein the at least one support rope (50) is connected to or guided by the support structure (40), such that pivoting the clamps (1) towards the second position (12) causes an extension of a first rope section (51) between the tensioning element (5) and the redirection means (6) of the respective clamp (1), a shortening of a second rope section (52) between the redirection means (6) and the support structure (40) as well as a movement of the support structure (40) towards the clamp tips (2), such that independently of a radial extent of the rotation-symmetric portion of the body (20) arranged on the support structure (40), a central point (P) of a cross-section of the rotation-symmetric portion of the body (20) has an essentially constant distance to the base structure (4); as well as a method for moving and/or manipulation of an object using the device (100).