Experimental characterization of the T-FLEX ankle exoskeleton for gait assistance

Designing robotic devices to assist or emulate the ankle is challenging due to the joint’s complexity and the fundamental role in walking. T-FLEX is an ankle exoskeleton based on vsa for rehabilitation and assistance of people with ankle dysfunctions. This device has presented promising motor recovery results for a stroke patient during a rehabilitation program. However, human walking applications require an electromechanical characterization to measure the device’s capabilities and determine the suitable configuration that responds to this complex task. This work presents T-FLEX’s experimental characterization carried out in a test bench structure. The results showed alterations in system times and actuators’ bandwidth because of the tendons’ force levels. Furthermore, this study determined the most appropriate T-FLEX configuration to obtain the best performance. Thus, this work also presents a preliminary validation under that configuration on a healthy subject in gait assistance to assess the device’s response in different velocities and measure the effects on the user. In conclusion, T-FLEX can assist the human gait for gait cycle duration greater than 0.74 s providing torque on the ankle of up to 12 Nm in propulsion and 20 Nm in dorsiflexion. Nevertheless, it should include an adaptable stage in the control architecture to counteract the stabilization time for providing the maximum torque at the right time.