Torque Control for Powered Orthosis Gait Adaptation
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Solution Overview
Problem
Conventional lower-limb exoskeletons rely on kinematic control methods that constrain patients to pre-defined walking patterns, limiting flexibility and preventing the relearning of natural gait, especially in rehabilitation settings, and lack effective bodyweight support mechanisms for kinetic control.
Innovation Solution
A nonlinear potential energy shaping control method is implemented in powered lower-limb exoskeletons, allowing for virtual bodyweight support by altering human dynamics through actuators, enabling patients to train natural walking motions without pre-defined patterns and providing flexibility in therapy settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If kinematic control methods are used to constrain patients to pre-defined walking patterns, then control stability is improved, but gait flexibility and ability to relearn natural gait deteriorate
Solution Approach 1:
The patent replaces traditional kinematic control (mechanical constraint of joint angles and velocities) with kinetic control that operates at the torque level. The controller generates torques to achieve desired kinetic goals rather than forcing pre-defined kinematic trajectories, allowing patients to naturally learn their own gait patterns while maintaining control stability through torque regulation.
Solution Approach 2:
The invention changes the control parameter from kinematic (joint angles, velocities) to kinetic (torques, energy). By controlling torques at each joint rather than constraining joint positions, the system provides stable control while allowing flexible adaptation to patient-specific gait patterns, enabling stroke patients to relearn natural walking.
2Adaptability or versatility
If kinetic control methods are used to provide flexible gait training, then gait flexibility is improved, but control complexity increases
Solution Approach 1:
The patent introduces an energy-based intermediary framework that simplifies kinetic control. By using energy concepts (power, work, efficiency) as the control intermediary rather than directly managing multiple torque parameters, the system achieves flexible gait training while reducing control complexity. The energy-based approach provides a unified framework for analyzing and controlling exoskeleton-assisted gait.
Data Source
AI summary
Orthosis device and related methods for controlling the device to counteract a gravitational force exerted on the person without directing the orthosis device in a pre-determined pattern of motion.