3-DOF Rotational Exoskeleton Joint Actuation Mechanism
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Solution Overview
Problem
Current exoskeleton technologies have a limited range of motion about the hip and ankle joints, which are capable of three rotational degrees-of-freedom, leading to bulkier devices and requiring additional equipment for stability, thus limiting user adoption due to inconvenience and effort.
Innovation Solution
A device with a motion generator, motion transfer and target interfacing unit, and controller that provides three degree-of-freedom rotational motion to the target joint, using a network of actuators and linkages to mechanically interconnect the motion generator to the target joint, and sensors for feedback and control, allowing decoupled or combined positioning without significant forces on the joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If current exoskeleton technologies use limited range of motion about hip and ankle joints, then device structure is simplified, but device becomes bulkier and requires additional stability aids
Solution Approach 1:
The hip joint is divided into three independent rotational degrees of freedom (flexion-extension, abduction-adduction, and internal-external rotation), each controlled by separate actuators. This segmentation allows full 3-DOF motion capability while maintaining a modular structure that avoids bulkiness through efficient space utilization.
Solution Approach 2:
The patent transitions from 1-DOF or 2-DOF joint actuation to full 3-DOF rotational actuation, adding a dimensional aspect to the motion capability. This enables the exoskeleton to match the human hip's natural 3D rotational movements, eliminating the need for compensatory stability aids and reducing overall device size.
2Device complexity
If current exoskeleton technologies actively guide only one degree-of-freedom hip-centered movements, then device structure is simplified, but payload-to-weight ratio decreases
Solution Approach 1:
The parallel robotic manipulator is designed to simultaneously control all three rotational degrees of freedom of the hip joint through a unified mechanism. This multi-functional approach eliminates the need for separate actuation systems for each DOF, improving the payload-to-weight ratio while maintaining full 3-DOF active guidance capability.
3Ease of manufacture
If current exoskeleton technologies use serial joint structure, then device is easier to manufacture, but device becomes bulkier than necessary
Solution Approach 1:
The patent merges multiple actuation functions into a single parallel robotic manipulator structure that simultaneously provides all three rotational DOFs. This consolidation eliminates the need for multiple serial joint chains, reducing device bulk while maintaining manufacturability through standardized parallel mechanism components.
4Reliability
If current exoskeleton technologies require walking sticks for stability, then user safety is improved, but ease of operation decreases
Solution Approach 1:
The exoskeleton system provides inherent stability through full 3-DOF active guidance of the hip joint, eliminating the need for external stability aids like walking sticks. The parallel robotic manipulator's capability to control all rotational degrees of freedom enables the device to self-maintain balance and support user safety without additional equipment, thereby improving ease of operation.
Data Source
AI summary
Examples of a device for guiding and detecting a motion of a target joints and a motion assistance system such motion guiding devices are described. The motion guiding and detecting device comprises a motion generator and a motion transfer and target interfacing unit to transfer the motion generated by the motion generator to the target joint. The system further includes a motion detection and feedback unit that interfaces with the target, and a controller that interfaces with both the feedback unit and the motion generator to control and coordinate the motion of the motion generator and the target joint.