Hip Joint Exoskeleton Kinematics for Higher Transparency
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Solution Overview
Problem
Exoskeletons often suffer from poor transparency due to kinematic misalignment, limited range of motion, bulk, mass distribution, and lack of coupling with the human body, leading to unnatural dynamics and constrained movement.
Innovation Solution
The exoskeleton incorporates a 3-DOF hip joint mechanism with a kinematic chain of abduction/adduction, internal/external rotation, and flexion/extension, using remote actuators and four-bar linkages to align with human kinematics, and a virtual-center scissor mechanism for internal/external rotation, along with a compound pulley rolling knee joint for enhanced transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a serial chain of rotational joints is used to match human hip kinematics, then transparency is improved, but device complexity increases
Solution Approach 1:
The hip joint mechanism is divided into separate rotational joints (abduction/adduction joint, internal/external rotation joint, flexion/extension joint) that can be independently designed and controlled, allowing complex human kinematics to be matched through coordinated motion of segmented components
Solution Approach 2:
The exoskeleton employs dynamic actuation systems that adjust joint parameters in real-time to match the wearer's natural hip kinematics, enabling transparency through adaptive motion rather than fixed mechanical constraints
2Stability of the object's composition
If the exoskeleton provides structural support across the hip joint, then stability is improved, but bulk and mass increase
Solution Approach 1:
The exoskeleton provides structural support selectively at critical locations (hip joint, knee joint, ankle joint) while minimizing material usage in non-critical areas, reducing overall bulk while maintaining necessary stability for load-bearing functions
Solution Approach 2:
The exoskeleton utilizes a backpack-mounted actuator system that positions mass away from the hip joint in the vertical dimension, allowing structural support functions to be achieved without adding bulk at the hip joint itself
3Measurement precision
If actuators are placed close to the hip joint, then control precision is improved, but mass at the joint increases
Solution Approach 1:
The patent introduces intermediate linkage mechanisms (four-bar linkages, scissor mechanisms) that transmit actuation forces from remote locations to the hip joint, allowing actuators to be positioned away from the joint while maintaining control precision through mechanical advantage
Solution Approach 2:
Actuators are relocated to the backpack region, utilizing the vertical dimension to position mass away from the hip joint. Linkage mechanisms transmit forces across space, decoupling actuator location from joint location and reducing mass at critical joints
4Adaptability or versatility
If the exoskeleton follows anatomical kinematic chains, then coupling with human body is improved, but range of motion is limited
Solution Approach 1:
The exoskeleton employs dynamic kinematic chains with adjustable parameters that can adapt to different human anatomies and motion requirements, allowing full range of motion while maintaining coupling through real-time parameter adjustment rather than fixed anatomical constraints
Data Source
AI summary
An increased transparency exoskeleton is provided that includes a hip joint assembly. The exoskeleton includes a hip joint assembly connecting a leg assembly to a torso portion. The hip joint assembly has a hip abduction/adduction to hip internal/external rotation to hip flexion/extension kinematic chain.