J. Biomedical Science and Engineering, 2014, 7, 208-217 Published Online March 2014 in SciRes. http://www.scirp.org/journal/jbise http://dx.doi.org/10.4236/jbise.2014.74024 How to cite this paper: Hussain, R., Massoud, R. and Al-Mawaldi, M. (2014) ANFIS-PID Control FES-Supported Sit-to-Stand in Paraplegics: (Simulation Study). J. Biomedical Science and Engineering, 7, 208-217. http://dx.doi.org/10.4236/jbise.2014.74024 ANFIS-PID Control FES-Supported Sit-to-Stand in Paraplegics: (Simulation Study) Rufaida Hussain, Rasha Massoud, Moustafa Al-Mawaldi Department of Biomedical Engineering, Electrical and Mechanical Engineering Faculty, Damascus University, Damascus, Syria Email: rufaidahussain@gmail.com Received 16 January 2014; revised 20 February 2014; accepted 28 February 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Adaptive Neuro-fuzzy Inference System (ANFIS) controller was designed to control knee joint during sit to stand movement through electrical stimuli to quadriceps muscles. The developed ANFIS works as an inverse model to the system (functional electrical stimulation (FES)-induced quadriceps-lower leg system), while there is a proportional-integral-derivative (PID) controller in the feedback control. They were designated as ANFIS-PID controller. To evaluate the ANFIS-PID controller, two controllers were developed: open loop and feedback controllers. The results showed that ANFIS-PID controller not only succeeded in controlling knee joint motion during sit to stand movement, but also reduced the deviations between desired trajectory and actual knee movement to ±5˚. Promising simulation results provide the potential for feasible clinical applica- tion in the future. Keywords Adaptive Neuro-Fuzzy Inference System (ANFIS); Functional Electrical Stimulation (FES); Sit to Stand; Model; Simulation 1. Introduction Sit to stand movement is necessary for many activities in human life. However, paraplegics have particular dif- ficulty with this movement due to their lower limb paralysis caused by spinal cord injury (SCI) [1]. They con- sider it as a big challenge and often require an assistant [2]. Moreover, they use arm support to provide neces-