Motion Assist Device Using Dynamic Oscillator for Variable Speed Force
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Solution Overview
Problem
Existing motion assist devices for creatures, such as humans with physical hypofunction, struggle to apply sufficient force to match the desired motion scale, especially when the creature moves slowly, as the strength of force applied is insufficient to match the motion scale with the desired scale.
Innovation Solution
A motion assist device with an orthosis, actuator, and controller that determines and adjusts the magnitude and phase of the output force using motion oscillators and virtual models to generate oscillation signals, ensuring appropriate force application regardless of motion rhythm, by setting intrinsic angular velocities and correcting models to approximate desired motion variables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the strength of force applied to the human is adjusted according to a spring model representing a behavior feature of a virtual elastic element, then the motion scale of the human can be matched with the desired motion scale when the human acts fast, but the strength of force becomes insufficient when the human acts slowly due to remarkable physical hypofunction
Solution Approach 1:
The patent applies dynamics by making the motion oscillator's parameters (angular velocity, amplitude) adjustable and adaptable to the user's actual motion state. The system dynamically adjusts the oscillator characteristics based on detected motion speed and phase, allowing the force application to adapt to both fast and slow motion rhythms. This resolves the contradiction by enabling the system to maintain appropriate force strength across varying speeds through real-time parameter modification rather than fixed spring model parameters.
Solution Approach 2:
The patent implements parameter changes by modifying the motion oscillator's intrinsic angular velocity and amplitude based on the user's actual motion rhythm. When the user moves slowly, the system adjusts the oscillator parameters to generate stronger force signals, and when the user moves fast, it adjusts to match the faster rhythm. This dynamic parameter adjustment allows the system to maintain effective force application across different motion speeds, resolving the contradiction between speed adaptation and force sufficiency.
2Productivity
If a periodically varying force is applied to assist the periodical motion of the creature, then the motion can be assisted, but the force strength becomes insufficient to match the desired motion scale when the creature moves slowly
Solution Approach 1:
The patent implements feedback by continuously detecting the user's actual motion state (speed, phase, position) and using this information to adjust the motion oscillator parameters and force application characteristics. The system monitors the user's motion rhythm and adapts the assistive force accordingly, ensuring that the force strength matches the desired motion scale regardless of whether the user is moving fast or slow. This closed-loop feedback mechanism resolves the contradiction by enabling real-time optimization of force strength based on actual motion performance.
Solution Approach 2:
The system dynamically adjusts the characteristics of the periodically varying force based on the user's actual motion state. By making the force application adaptive rather than fixed, the system can increase force strength when the user moves slowly and reduce it when the user moves fast, maintaining effectiveness across different motion speeds. This dynamic adaptation resolves the contradiction between providing motion assistance and ensuring sufficient force strength.
3Manufacturing precision
If the motion scale of the human is matched to the desired motion scale using a spring model, then fast actions can be assisted with sufficient force, but the matching fails when the human acts slowly due to physical hypofunction
Solution Approach 1:
The patent achieves both precise motion scale matching and adaptability to different motion rhythms by implementing a dynamic motion oscillator whose parameters (angular velocity, amplitude, phase) are continuously adjusted based on the user's actual motion state. Unlike the fixed spring model, this dynamic oscillator can adapt its characteristics to match the desired motion scale precisely regardless of whether the user is moving fast or slow. The system detects the user's motion rhythm and adjusts the oscillator parameters accordingly, maintaining high precision matching across varying speeds and demonstrating versatility to different motion patterns.
Solution Approach 2:
The system achieves precise motion scale matching and adaptability through parameter changes in the motion oscillator. By adjusting the intrinsic angular velocity, amplitude, and phase of the oscillator based on the user's actual motion state, the system can precisely match the desired motion scale for both fast and slow movements. This parameter adaptation mechanism allows the system to maintain high precision in motion scale matching while being highly adaptable to different motion rhythms, resolving the contradiction between precision and versatility.
Data Source
AI summary
A motion assist device for assisting a periodical motion of a creature such as a human by applying a force with appropriate strength to the creature so as to match a motion scale with a desired motion scale thereof regardless of a motion rhythm of the periodical motion. According to the motion assist device (1), a second model is corrected so as to approximate a value of a motion variable (ξ) to a desired value (ξ0). A second oscillator (ξ2) is generated according to the corrected second model. A periodical force (torque) (T) applied to the human (P) is controlled according to the second oscillator (ξ2).