Wearable human lower limb prototype exoskeleton: An operative approach

This paper presents a functional wearable prototype exoskeleton with partial automation of a human lower limb exoskeleton for torque estimation and position control of the three main joints: hip, knee and ankle. To obtain information of the angular position in which each limb is placed, several Inertial Measurement Unit (IMU) sensors allow accurate data due to the use of a sensor fusion algorithm. An arrange of programmable microcontrollers and DC motors are used in the experimental prototype to generate the reference signals and control the angular position of each joint. In particular, a Network Control System (NCS) is developed and implemented as a dedicated Network using a Controller Area Network (CAN) physical Layer according to the Open System Interconnection (OSI) model. Electronic interface modules were designed and implemented as well, in order to enable the Network Control System to transmit data. In this work, we used one degree of freedom for hip and ankle joints to simplify and mimic the pace when walking straight forward. PID controllers were tuned up for hip, knee and ankle movements, i.e., flexion and extension for hip and knee joints, dorsiflexion and plantarflexion for ankle joint. Experimental results showed good tracking and regulation behavior and good fidelity measure was obtained.