Development of an Active Cable-Driven, Force-Controlled Robotic System for Walking Rehabilitation

Applying elastic resistance bands for gait training: A simulation-based study to determine how band configuration affects gait biomechanics and muscle activation

BACKGROUND

Wearable robotic exoskeletons and leg braces are desirable for gait rehabilitation because they can apply loads directly to an affected joint. Yet, they are not widely used in clinics because they are costly and complex to set up. Conversely, tethered devices, such as elastic resistance bands, are widely available in clinics, are low-cost, and are quick to set up. However, resistance bands will affect walking differently based on how they are configured to pull on the leg (e.g., pulling forward or backward).

RESEARCH QUESTION

How can a resistance band be configured to alter muscle activation and gait biomechanics based on the segment it is attached to and the angle with which it attaches?

METHODS

We used an open-source musculoskeletal modeling platform to emulate several configurations of an elastic band pulling on the ankle, calf, and thigh at various angles during non-pathological walking. We evaluated gait biomechanics and simulated muscle activation using computed muscle control (CMC) and identified a subset of four configurations with potential applications for gait training. Eight non-pathological participants then walked on a treadmill under these configurations to verify how these configurations altered muscle activation.

RESULTS

We found that muscle activity greatly varied based on the location where the elastic band is attached and the angle with which the elastic band pulls on the leg. Notably, specific angles can be used to pull on the legs to elicit an increase or decrease in muscle activation.

SIGNIFICANCE

This study provides insight into how tethered devices can be configured to provide assistance or resistance during gait training. This information can be applied when developing low-cost gait training solutions for addressing individuals' impairments.

Development of a Belt-actuated Robotic Platform for Early Rehabilitation

In order to promote early rehabilitation, we proposed a system which provides full-body arm-leg training for patients in a bed-lying position. As the preliminary development, a platform for leg movement was investigated. An innovative system with four servo drives was designed and manufactured. An artificial leg frame was attached to the platform via belts. The positions of the hip and knee joints were recorded using potentiometers. Closed-loop PID position control algorithms were implemented for production of various stepping movements. Technical evaluation on a test participant showed that the platform tracked the circular trajectory of the foot in a supine-lying position with an area difference of 8.2%, and produced walking-like trajectories in the hip and knee joints in a side-lying position with a mean error of 10.6%. The mechanical structure can be resized, and the control system can be expanded, so as to produce 3-dimensional stepping movement in both arms and legs. This innovative platform combined with the closed-loop position control strategy shows the technical potential to be a promising full-body rehabilitation platform for the patients in the early post-injury stage.