Mechanical Design And Control Of A Portable Lower Limb Gait Rehabilitation Robot

In recent years,various lower limb rehabilitation devices such as exoskeletons are developed to overcome the drawbacks of traditional gait training methods.Conventional portable exoskeletons are limited in their feature's functionality,and modern exoskeletons are often complex systems,which make them unfeasible for home settings due to their high cost.Moreover,the current exoskeletons are limited in their ability to consume lesser energy which leads to the selection of actuators with high power,high weight and increased cost.In order to overcome these challenges,a novel approach is adopted in the design of exoskeleton.The mechanical and control design of a portable lower limb gait rehabilitation robot is presented in this thesis.The designed robot is compact,portable,lightweight,and cost-effective for a home setting.The robot includes an extension springs-based linkage which stores energy during the phase of low energy requirement and utilizes the stored energy when peak force is required(stance phase).This linkage also provides compliance,additional safety and smooth operation of the device.The robotic system is designed according to the natural gait pattern of humans during walking.The robotic system consists of main mechanical structure,a simple parallelogrammical linkage incorporating two parallel extension springs,and a four-bar slider crank mechanism.A ball screw-nut transmission system is used which is actuated by a brushless DC motor.The dimensional synthesis of the whole linkage is carried out,and the robotic joint mechanism is then optimized to minimize the input force required to rotate the joint while keeping the design compact and portable.Mechanical structure of the robot is designed by considering the factors of safety,ergonomics,cost,durability and weight.An effective control strategy is adopted to acquire the desired motion patterns from the robot.Pressure sensors are used for human-robot interaction and magnetic rotary sensors are employed to detect the joint angles to control the amount and direction of required torque.This work introduces a novel approach to consume lesser energy for exoskeleton operation on the basis of gait data.In this way,this work opens up new ways towards innovative designs of lowcost and efficient lower limb rehabilitation robots which can be used in a home setting.