title: Design of a heart rate controller for treadmill exercise using a recurrent fuzzy neural network.
abstract: OBJECTIVE
  In this study, we developed a computer controlled treadmill system using a recurrent fuzzy neural network heart rate controller (RFNNHRC). Treadmill speeds and inclines were controlled by corresponding control servo motors. The RFNNHRC was used to generate the control signals to automatically control treadmill speed and incline to minimize the user heart rate deviations from a preset profile.
  
  
  METHODS
  The RFNNHRC combines a fuzzy reasoning capability to accommodate uncertain information and an artificial recurrent neural network learning process that corrects for treadmill system nonlinearities and uncertainties. Treadmill speeds and inclines are controlled by the RFNNHRC to achieve minimal heart rate deviation from a pre-set profile using adjustable parameters and an on-line learning algorithm that provides robust performance against parameter variations. The on-line learning algorithm of RFNNHRC was developed and implemented using a dsPIC 30F4011 DSP.
  
  
  RESULTS
  Application of the proposed control scheme to heart rate responses of runners resulted in smaller fluctuations than those produced by using proportional integra control, and treadmill speeds and inclines were smoother. The present experiments demonstrate improved heart rate tracking performance with the proposed control scheme.
  
  
  CONCLUSIONS
  The RFNNHRC scheme with adjustable parameters and an on-line learning algorithm was applied to a computer controlled treadmill system with heart rate control during treadmill exercise. Novel RFNNHRC structure and controller stability analyses were introduced. The RFNNHRC were tuned using a Lyapunov function to ensure system stability. The superior heart rate control with the proposed RFNNHRC scheme was demonstrated with various pre-set heart rates.
authors.affiliation: Department of Electrical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chun-Hao
authors.initials: CH
authors.lastname: Lu
authors.affiliation: Department of Electrical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Wang
authors.affiliation: Department of Electrical Engineering, National Cheng Kung University, Tainan, Taiwan. Electronic address: astar2.elc@gmail.com.
authors.forename: Cheng-Chi
authors.initials: CC
authors.lastname: Tai
authors.affiliation: Department of Computer and Communication, Kun Shan University, Tainan, Taiwan.
authors.forename: Tien-Chi
authors.initials: TC
authors.lastname: Chen
mesh_terms: D000328:Adult; D000465:Algorithms; D003198:Computer Simulation; D004867:Equipment Design; D005080:Exercise Test; D017143:Fuzzy Logic; D006339:Heart Rate; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods*; D016571:Neural Networks, Computer; D012420:Running; D055815:Young Adult
keywords: Adjustable parameters; Computer controlled treadmill; Heart rate controller; On-line learning algorithm; Recurrent fuzzy neural network; Treadmill speed and incline