Motion Assist Device Oscillator Control for Walking Rhythm and Scale
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Solution Overview
Problem
Existing motion assist devices fail to maintain a balance between motion rhythm and motion scale, leading to uncomfortable user experiences during walking, especially during training, as they do not effectively synchronize the user's rhythm and scale with desired values.
Innovation Solution
A motion assist device that utilizes auxiliary oscillators generated based on user motion data, incorporating virtual elastic elements and phase differences to regulate torque application, ensuring synchronization of motion rhythm and scale with desired parameters, and adjusting parameters to maintain a balanced walk ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a walk assist device maintains appropriate motion rhythm through oscillator control, then the user's walking rhythm is synchronized, but the motion scale may deviate from desired values causing uncomfortable feeling
Solution Approach 1:
The device continuously measures the user's actual motion scale (footstep, joint angle) and compares it with the desired motion scale. Based on the deviation detected, the control system adjusts the assist force in real-time to correct the motion scale while maintaining the synchronized rhythm, thereby eliminating uncomfortable feelings caused by scale deviation.
Solution Approach 2:
The control system dynamically adjusts multiple parameters including assist force magnitude, action distance, and oscillator characteristics based on the detected deviation between actual and desired motion scale. By changing these parameters adaptively, the system maintains both appropriate rhythm and comfortable motion scale simultaneously.
2Length of moving object
If elastic element models are used to match motion scale to desired values, then the motion scale is corrected, but the balance between motion rhythm and motion scale cannot be maintained
Solution Approach 1:
The system transitions from static elastic element models to a dynamic control approach where assist force and action distance are continuously adjusted based on real-time feedback. This dynamic adaptation allows the system to maintain the delicate balance between motion rhythm and motion scale by responding to changing user needs and environmental conditions.
Solution Approach 2:
The control system proactively adjusts assist parameters before significant deviations occur by continuously monitoring the relationship between rhythm and scale. This preliminary action prevents imbalance from developing, maintaining stable coordination between temporal (rhythm) and spatial (scale) characteristics of walking.
3Length of moving object
If assist force or action distance is increased to correct motion scale, then the motion scale approaches desired values, but the walk rhythm may become inconsistent with desired rhythm
Solution Approach 1:
The control system separates the control of motion scale and motion rhythm into independent adjustable parameters. Assist force magnitude controls the scale (how far the leg moves), while action distance and timing control the rhythm (when the motion occurs). This segmentation allows independent optimization of both scale and rhythm without mutual interference.
Solution Approach 2:
The system dynamically coordinates adjustments of multiple parameters (assist force, action distance, timing) to simultaneously achieve desired scale and rhythm. Rather than adjusting one parameter at a time, the control system makes coordinated changes that maintain the relationship between temporal and spatial aspects of walking motion.
Data Source
AI summary
The motion assist device (200) is provided with an auxiliary oscillator generation element (150) configured to generate, on the basis of a second intrinsic angular velocity (ω2) set according to a first oscillator (ξ1) generated from a first motion oscillator (φ1) and a first model and a second oscillator (ξ2) generated from a second motion oscillator (φ2) and a second model, an auxiliary oscillator (η) which includes therein a first auxiliary oscillator (η1) denoting an elastic force originated from a virtual elastic element for assisting the motion of the user so as to approximate a value of a third motion oscillator (φ3) to a desired value (φ0+, φ0−) related to a desired motion scale of the user, and an auxiliary oscillator regulation element (160) configured to sequentially regulate the first auxiliary oscillator (η1) so as to approximate a motion index value of the user to a reference value.