Page 294 - Control Theory in Biomedical Engineering

CHAPTER 10

A double pendulum model for

human walking control on the

treadmill and stride-to-stride

fluctuations: Control of step

length, time, velocity, and position

on the treadmill

a
a
a
Alireza Bahramian , Farzad Towhidkhah , Sajad Jafari ,
Olfa Boubaker b
a
Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Iran
b
University of Carthage, National Institute of Applied Sciences and Technology, Tunis, Tunisia
1 Introduction

Walking can be defined as a rhythmic movement of limbs that maintains
animals and humans in constant forward displacement (Rao et al., 2010).
It is generated by sophisticated interactions between motor centers in the
brain, neural spinal circuits and reflexes, numerous muscles, different sensory
systems, and the environment. The nervous system controls the body as a
complex system via the integration of sensory feedbacks including visual
(Salinas et al., 2017), vestibular (Larsson et al., 2016), and proprioceptive
(Pearson, 2004), as well as a type of internal model(s) in the brain
(Karimian et al., 2006) to maintain dynamic stability and effective walking.
There are several internal (neurobiological) (Lewek et al., 2009; Faisal et al.,
2008) as well as external (environment) (Su and Dingwell, 2007) sources of
uncertainties (noises) that cause each step to become slightly different from
the others (Hausdorff, 2007). These variabilities may contain valuable infor-
mation about how the nervous system reacts to these noises to regulate limb
movements. For example, the variabilities of movements increase with
advancing age in older adults (Kang and Dingwell, 2008). These variations
are correlated with the individuals’ falls history (Toebes et al., 2012) and the
likelihood of falls in the future (Verghese et al., 2009). Also, the increase of
variabilities in movements facilitates motor learning during rehabilitation

Control Theory in Biomedical Engineering © 2020 Elsevier Inc.
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