Development Of Lower Limb Exoskeleton Research Articles

Development of Lower Limb Exoskeleton for Walking Assistance Using Energy Recycled From Human Knee Joint

Abstract This paper illustrates the design and testing of a lower limb exoskeleton for walking assistance. First, the biomechanics of the human knee and ankle joints during walking and the strategy of energy recycling and releasing are introduced. Next, the hardware design of the exoskeleton is described. The exoskeleton is primarily composed of a waist module, a knee module, and an ankle module. Two clutch mechanisms are designed for one-way motion transmission, and an energy storage spring is designed to store the energy recycled from the human knee motion. Additionally, the modeling of the human-exoskeleton system is presented. Finally, experiments are conducted to verify the effectiveness of the developed exoskeleton. The experimental results demonstrate that the exoskeleton has the potential to recycle the negative work from the wearer’s knee flexion during the late stance phase and knee extension during the swing phase to assist the wearer’s ankle plantarflexion during the stance phase. During a gait cycle, reductions of 11.6% and 15.6% of the average muscle activities of the gastrocnemius and soleus are observed, respectively. In addition, the peak gastrocnemius and soleus activities during the push-off stage are reduced by 16.9% and 42.6%, respectively.

Design and development of lower limb exoskeletons: A survey

Research into the development of the lower limb exoskeleton (LLE) has been on-going since the 1960s. Although this field has long been explored, the technological progress has been very slow. Many exoskeletons were stopped in their tracks toward commercialization at the research stage itself. Therefore, this paper is aimed at systematically reviewing the design and development of multiple joint LLEs. The discussion focuses on the application of LLEs for augmentation, muscle weakness or gait recovery and rehabilitation. Details of aspects such as the control strategy, actuator, safety and design, including compactness, noise, heavy structural weight, cost, mimicking of natural walking, and power sources, will be discussed. Finally, issues concerning the design and development of LLEs will also be presented.

Development and Repetitive Learning Control of Lower Limb Exoskeleton Driven by Electrohydraulic Actuators

This paper presents a novel development of lower limb exoskeleton, which is named as CASWELL, and its repetitive learning control design for movement assistance. CASWELL has five degrees of freedom per leg, two of which are driven by linear single-rod electrohydraulic actuators. First, the mechanical structure and embedded electronic system are constructed, respectively. Second, by incorporating the systems of rigid body and electrohydraulic actuators, the complete dynamics of CASWELL are analyzed and modeled. Third, under the framework of backstepping design, a repetitive learning control scheme is presented to address the periodic tracking control of lower limbs of exoskeleton, where the learning convergence of the closed-loop system is proved rigorously in a Lyapunov way. Finally, the proposed controller is implemented in the embedded electronic system via a 32-bit microcontroller, and tested on the developed CASWELL. The experimental results are given to demonstrate the performance of the whole exoskeleton system.