Mathematical modeling and control of lower extremity exoskeleton

In this study, a new active control strategy of 2 degrees of freedom exoskeleton robot was realized. Firstly, a double-pendulum mechanism is used to demonstrate the human amplifier robot which follows and assists the healthy human low body movements. Secondly, mathematical model of this system is created and the PID control method was applied to the robot. Feedback information for controller was supported via the pressure forces sensors, which located at the front and rear of the leg between the human leg and the double-pendulum links. The simulation results are obtained for three motion scenarios and interpreted graphically. According to the graphically obtained results, it is obvious that the robot can successfully follow the human leg under different load conditions and successfully carry these loads without transferring them to the leg muscles. The proposed TDB model appears to be a suitable model for describing the motion of the exoskeleton robot