Walking simulation model of lower limb exoskeleton robot design

Abstract

Since 1960s, the development of exoskeleton robots have been advancing in the applications such as load carrying, walking endurance, physical assistance and rehabilitation therapy. Rehabilitation therapy in itself is related to walking ability restoration; especially for the elder people. A survey by The United Nations in 2017 revealed increase trend in the number of ageing population. Due to ageing, it may cause weakened limbs, lower limb injuries or disabilities resulting in walking impairment. Elder people suffering from walking impairment will need to undergo walking therapy to recover walking ability. A walking rehabilitation exoskeleton robot can be used for such patients to undergo the therapy by wearing it on their lower body. A lower limb exoskeleton effectiveness for gait recovery assessment in the design stage is not truly explored yet. This can be done by obtaining the simulation model of the lower limb exoskeleton robot structure from its CAD design. The gait pattern tracking response performance of the exoskeleton design to given inputs can then be observed. The lower limb exoskeleton structure is designed using Autodesk Inventor and then imported into SimMechanics. A block diagram of the exoskeleton model is generated, whereby the model is simulated and its response is observed. Given mathematical expression and experimental data inputs, the exoskeleton model with control system is able to track given joint trajectory inputs. The lower limb exoskeleton model shows that the response of its joints to the inputs can replicate human joints behavior during walking for any given stimulus inputs.