In this paper the implementation of PID controllers for the development of passive rehabilitation exercises are presented. For which it is designed and built an ankle rehabilitation prototype based on a structure of parallel robot with a mechanism of the type 2-RRSP (two closed kinematic chains and consisting of joints: revolute-revolute-sphere in slot-fixed post with sphere). Free software is used to develop the computer programs associated with rehabilitation exercises. Regarding the laboratory testing stage, the results of passive exercises are reported, in these exercises path planning is included and PID control is used, for inversion-eversion, dorsal-plantar flexion and combined movements.