Investigating the effect of a passive exoskeleton on the activity of low back muscles during different phases of repetitive dynamic task

Abstract

In literature, there are multiple lines of work aimed to develop human-centered robotic devices, and among them there is a promising one named robotic exoskeleton. Exoskeletons are biomechatronic devices coupled to the person's body (a “wearable” robot) (Pons, 2008). In general, exoskeletons are composed of a structural mechanism with joints and links, which is worn by the human user. Hence, the whole kinematic structure usually performs several motions similar to those of the human body. Exoskeletons are devices designed to enhance the human strength by the external framework, thus those devices are currently under development for the enhancement of human motor performance in the military (Zoss et al., 2006), in industry (de Looze et al., 2015), and for medical applications (Colombo, 2001; Veneman, 2007; Gijbels et al., 2011).Technological developments on exoskeletons started in the early 1960s. The US Department of Defense became interested in developing the concept of a powered “suit of armor.” In parallel, researchers at Cornell Aeronautical Laboratories started to develop the concept of man amplifiers such as a manipulator to increase the strength of a human operator (Kazerooni, 1990). In 1962, the technological limitations at that time to develop the concept became apparent: there were limitations in terms of actuators, sensors, and energy storage. Currently, most of those technological limitations have been overcome and applications of exoskeletons have been spreading in multiple fields, including teleoperation with force feedback, power amplifier, entertainment as well as the physical rehabilitation. The rehabilitation field is a key application domain for the development of exoskeletons, to help disabled people with difficulties in moving (Kiguchi et al., 2004; Colombo, 2001). For instance, these devices enable people with paralysis of the lower part of the body (paraplegia) to walk (Esquenazi et al., 2012). Their task is the compensation for the lost functions and physical and social rehabilitation of patients. Nowadays, the exoskeleton systems are forging ahead with high integration using other emerging technologies including virtual reality, haptics, videogames, and soft robotics, among others.