Three-DoF Ankle Exoskeleton With Symmetric Frame And Torque Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ankle exoskeletons primarily focus on a single axis of rotation, neglecting the comprehensive range of ankle movements, compromising kinematic compatibility and weight, and lack precise angle and torque measurement, mechanical adjustability, and adaptability across diverse user anatomies.
Innovation Solution
An individually customizable ankle exoskeleton design with at least three degrees of freedom (DoF) featuring a symmetric parallel frame structure, adjustable components, and integrated sensors for precise torque and angle measurement, allowing use on either leg and minimizing weight through evenly distributed actuation forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ankle exoskeletons incorporate sufficient movable joints to harmonize with user's kinematic structure for all three DoF, then kinematic compatibility and range of motion are improved, but device complexity, weight, and bulkiness increase
Solution Approach 1:
The exoskeleton is divided into modular components: a shoe interface assembly, an ankle assembly with separate DoF mechanisms, and a calf interface assembly. Each module can be independently designed, adjusted, and optimized, reducing overall system complexity while maintaining full DoF capability
Solution Approach 2:
The device incorporates dynamic adjustment mechanisms including adjustable cushioning elements, movable ankle joints, and adaptable strap systems that can be configured in real-time to match user anatomy and movement patterns, enhancing kinematic compatibility without permanent complexity
2Adaptability or versatility
If ankle exoskeletons incorporate sufficient movable joints to harmonize with user's kinematic structure for all three DoF, then kinematic compatibility and range of motion are improved, but weight increases
Solution Approach 1:
The device utilizes flexible cushioning elements, elastic straps, and thin-walled structural components that provide necessary compliance and motion range without adding significant weight. The flexible interfaces allow full DoF movement while keeping the overall mass low
Solution Approach 2:
By segmenting the exoskeleton into lightweight modular components connected by flexible interfaces, the design achieves full range of motion through distributed flexibility rather than heavy centralized mechanisms
3Adaptability or versatility
If conventional devices use actuators positioned anterior on the shin pulling on struts, then limited inversion/eversion and internal/external rotation are permitted, but accurate measurement capabilities for all three ankle rotations and joint torque are lost
Solution Approach 1:
The patent replaces conventional mechanical actuation with a measurement-focused approach using strain gauge sensors embedded in the structural members. This substitution enables precise measurement of forces and moments while maintaining passive mechanical motion capabilities through the bearing arrangements
Solution Approach 2:
Strain gauge sensors provide real-time feedback on joint torques and forces acting on the ankle, enabling accurate measurement of all three rotational degrees of freedom. This feedback mechanism allows the device to adapt to user needs while maintaining measurement precision
4Adaptability or versatility
If ankle exoskeletons are designed with symmetric parallel frame structure and adjustable components, then adaptability across diverse user anatomies and mechanical adjustability are improved, but device complexity increases
Solution Approach 1:
The symmetric parallel frame structure serves multiple functions: it provides structural support, enables bidirectional wear (left or right leg), accommodates diverse anatomies through adjustment mechanisms, and maintains measurement capability. This multi-functionality reduces the need for separate components for each function
Solution Approach 2:
While the overall frame is symmetric, the design incorporates asymmetric adjustment capabilities and interchangeable components that allow adaptation to asymmetric user anatomies. The symmetric structure itself reduces complexity by allowing the same design to be used on both legs
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Exoskeleton, comprising: a assembly having a fixture (1) fixing a foot thereto, having two points arranged on each side of the fixture, and a frame (2) positioning the points relative to each other, that is connected to the fixture, and having an area; an arrangement (3) is inserted at each of the points; two struts, each of which is mounted with one of the ends of the arrangements over two axes and each of which has another arrangement at the other end and another area at the respective strut; another frame positioning the other arrangements relative to one another and is mounted relative to the struts; another assembly with another fixture fixing a lower leg, wherein the other frame is fixed between the other arrangements with the other frame; wherein both other areas are each connected to the area via a tension element; and an actuator adjusting the tension elements.