In this paper, the development of controlling a six Degree of Freedom (DOF) Lower Limb Exoskeleton (LLE) model using the Robot Operating System (ROS) is presented. Moreover, this work proposes a method to analyze kinematic properties and control of the LLE before the prototype. The model of the LLE is described using Extensible Markup Language (XML) programming in the Unified Robot Description Format (URDF). The dynamic equation of the six-DoF LLE is determined by using Newton-Euler. In addition, a Proposition-Integral-Derivative (PID) controller is established in a feedback closed-loop control system. The PID controller is tuned via Ziegler-Nichols (Z-N). The tuned PID controller is tested in the Gazebo environment to confirm the performance of the proposed method. The nodes and topics flow chart of the programmed 3-D model of the LLE is described. Furthermore, a desired angular trajectory based on the phase on walking is defined for each joint of the LLE. The result shows that the actual pursue the desired angular trajectory for each joint. The average and maximum error of the angular trajectories for all the joints are less than 0.05 radian. It can be ascertained that our developed LLE model in the Gazebo simulator can be used for giving an overview of the walking pattern.

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A development of trajectory planning and simulation for a four degree-of-freedom (DOF) biped reciprocating gait orthosis (RGO) for paraplegic is presented in the paper. Trajectory planning in joint space is developed using linear segments with parabolic blends (LSPB) method and presented graphically. The design of the RGO structure is developed in Solidworks and linked to MATLAB SimMechanics via xml mode. The input of generated model is fed according to the measured angular position trajectory of hip and knee joint actuator using Signal Builder block from MATLAB Simulink library and the simulation is shown graphically. The result of the simulation shows the RGO movement is imitating the desired trajectory quite similarly in each gait cycle and verified a normal walking gait pattern. The developed trajectory planning in this paper can 1298 Mohd Aizat Ahmad Tarmizi et al.be used as an input signal for the system in further advanced RGO control development.