Effective Shape Controller for Lower Limb Prosthetics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current powered lower limb devices for amputees require extensive tuning by highly trained clinicians and are not adaptable to varying tasks or conditions, leading to discomfort and instability due to their inability to mimic the natural walking shape of able-bodied limbs.
Innovation Solution
A control system for lower limb devices that utilizes a virtual constraint based on the effective shape, determined by the center of pressure (COP) or other monotonic variables, to adjust joint positions, velocities, and torques, allowing for coordinated control of multiple joints and adaptability to different tasks without individual user configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If prior art control systems use segmented gait cycle phases with multiple control parameters, then joint control can be implemented, but extensive tuning by highly trained clinicians is required and the system is not adaptable to varying tasks or conditions
Solution Approach 1:
The patent changes the control parameter from segmented phase-based control to continuous effective shape control. Instead of using multiple discrete control parameters for different gait phases, the system uses a single continuous parameter (effective shape) that naturally adapts to varying tasks and conditions, eliminating the need for extensive clinician tuning while maintaining joint control capability
Solution Approach 2:
The effective shape control approach provides universal control that works across multiple tasks and conditions without requiring task-specific configuration. A single control framework handles walking, running, and other locomotion patterns adaptively, making the system versatile without increasing complexity
2Reliability
If prior art control systems manually tune multiple control parameters for each user, then joint control can be achieved, but the process requires significant time and expertise
Solution Approach 1:
The system performs self-configuration by automatically determining the effective shape from sensor data without requiring manual tuning by clinicians. The control parameters are derived adaptively from the user's actual movement patterns, enabling the device to configure itself and eliminate time-consuming setup procedures while maintaining reliable joint control
3Reliability
If prior art systems use look-up tables with discrete gait phases, then joint trajectories can be tracked, but the system is not robust to external perturbations that push joint kinematics forward or backward in the gait cycle
Solution Approach 1:
The patent transitions from static look-up table control to dynamic effective shape control. The effective shape is continuously updated based on real-time sensor feedback, allowing the control system to adapt dynamically to external perturbations and maintain robust joint trajectories without requiring complex phase-detection mechanisms
Data Source
AI summary
Systems and methods for improved control of a lower limb device are disclosed. The lower limb may have one or more joints and one or more corresponding motors. In some embodiments, a center of pressure is calculated in order to enforce virtual constraints at the one or more joints of the lower limb device. The system utilizes one or more effective shapes, and each effective shape's corresponding error, in order to cause each joint motor to produce a torque that causes the joint to move according to a virtual constraint. The systems and methods result in improved control of lower limb devices.