Motion Assist Device Attitude Detection for Load Minimization
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Solution Overview
Problem
Conventional knee joint motion assist devices often apply undue loads to other body parts, such as the hip joint, and increase power consumption when the user's attitude is not optimal for the motion being performed, leading to reduced effectiveness and shorter battery life.
Innovation Solution
A motion assist device with a brace, drive unit, and attitude detection sensor that activates the drive unit only when the user assumes an optimal attitude for the prescribed motion, minimizing load on other body parts and reducing power consumption by using sensors like pressure sensors or angle sensors to detect the user's attitude and adjust assist torque accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive unit is activated continuously to assist knee joint motion, then the assistive function is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The drive unit is activated periodically based on detected motion phases rather than continuously. The control unit activates the drive unit only during specific phases of the knee joint motion cycle when assistance is most beneficial, creating a periodic activation pattern that reduces overall power consumption while maintaining effective assistive function during critical motion periods
Solution Approach 2:
The system uses sensors to detect knee joint angle and motion phase, providing feedback to the control unit which then adjusts drive unit activation accordingly. This closed-loop feedback mechanism ensures the drive unit operates only when needed based on real-time motion detection, optimizing the balance between assistive function and power consumption
2Reliability
If the drive unit provides continuous assistance regardless of user attitude, then the motion assist function is improved, but load on other body parts such as hip joint increases
Solution Approach 1:
The drive unit provides assistance periodically based on detected user attitude and motion phase rather than continuously. By activating the drive unit only during specific phases when the user is in an optimal attitude position, the system reduces unnecessary assistance that would otherwise transfer excessive load to the hip joint and other body parts
Solution Approach 2:
The assistance is applied locally and selectively based on the detected knee joint motion phase and user attitude. The control unit adjusts the assistive torque locally in time and space, providing maximum assistance only when the user's body posture indicates optimal conditions, thereby preventing excessive load transfer to other body parts
Data Source
AI summary
A motion assist device, comprises a brace (2, 3, 5, 6, 11; 23, 24, 32, 35) configured to be worn by a user, an assist motor (4, 34) provided in association with the brace to assist a prescribed motion of the user, a control unit (10; 40) for controlling an operation of the assist motor, and an attitude detection sensor (8, 18; 38) connected to the control unit for detecting an attitude of the user. The control unit is configured to activate the assist motor when a prescribed attitude of the user is detected by the attitude detection sensor so that loads on parts of the user's body other than the part which is directly assisted can be minimized.