Hip Exoskeleton Torque Assist With Free-Motion Engagement
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Solution Overview
Problem
Existing exoskeletons are bulky, cumbersome, and hinder free motion, failing to effectively assist hip extension during lifting and pushing tasks, leading to increased fatigue and risk of back injuries, particularly in older workforces.
Innovation Solution
A hip assist actuation system with a lever mechanism and drive mechanism that transitions between free and engaged modes based on hip extension angles, using sensors and motors to provide torque assistance only during lifting and pushing, allowing for free motion in other tasks and reducing lumbar forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drive mechanism is continuously engaged to provide torque assist, then lifting and pushing assistance is improved, but freedom of motion and user comfort deteriorate
Solution Approach 1:
The drive mechanism transitions between engaged and disengaged states dynamically based on detected activity type. During lifting and pushing tasks, the mechanism is engaged to provide torque assist. During walking and other free motion activities, the mechanism is disengaged to allow natural movement without resistance or mechanical interference.
2Force
If the exoskeleton structure is made robust to support heavy lifting, then lifting capacity is improved, but device weight and bulkiness worsen
Solution Approach 1:
The exoskeleton is divided into modular components including a hip belt, lever mechanism, and drive mechanism that can be independently optimized. The lever mechanism uses a fourth-class lever configuration with the fulcrum at the hip joint, allowing mechanical advantage to be achieved without requiring a heavy overall structure.
Solution Approach 2:
The system changes its mechanical parameters dynamically by adjusting the engagement state of the drive mechanism. When engaged, the mechanism provides high torque for lifting; when disengaged, it presents minimal resistance to natural motion, effectively changing the system's mechanical impedance based on task requirements.
3Power
If the lever mechanism is designed to provide high torque assist, then lifting effectiveness is improved, but complexity of the mechanism worsens
Solution Approach 1:
A linear actuator serves as an intermediary component between the motor and the lever mechanism. The linear actuator converts rotational motor motion into linear displacement that directly pushes or pulls the lever, simplifying the power transmission path and reducing the number of mechanical components required compared to traditional rotary actuation systems.
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 system provides targeted assistance for hip extension during heavy lifting and pushing, reducing fatigue and injury risk while maintaining natural movement and comfort, enhancing productivity and user experience.
Implementation Method 1
The drive mechanism may comprise: an electric motor; a screw operably coupled to the electric motor; and a glide element configured to translate along the screw in response to the screw rotating.
Implementation Method 2
a screw operably coupled to the electric motor; and a glide element configured to translate along the screw in response to the screw rotating
Implementation Method 3
a lever mechanism pivotably coupled to the support structure, the lever mechanism includes an upper arm extending away from a pivot point in a first direction and a lower arm extending away from the pivot point in a second direction
Data Source
AI summary
A hip assist actuation system is configured to allow a user to experience free movement of hip extension and hip flexion over a predetermined range and receive a torque assist in response to performing a lifting or pushing activity. The hip assist actuation system may be configured to determine whether the lifting or pushing activity is occurring and provide the torque assist in response to the determination.