Mechatronic Design of Low-Cost Control Systems for Rehabilitation and Assisting Devices

Introduction

Recent studies report that the number of elderly and people with motion disabilities that cannot perform Activities of Daily Life (ADL) without the help of other people is increasing. In order to face this problem, nurses, caregivers or relatives are involved for continuous aiding at home, alternatively, a number of commercial solutions have been developed to help the execution of some tasks. Among several ADL, such as walking, feeding, bathing, toileting, we are interested in the Sit-To-Stand (STS), which is one of the most frequent and, despite its apparent simplicity, it is a mechanically demanding functional task undertaken daily, requiring a strong coordination between posture and movement. Some commercial solutions were developed (Hari Krishnan & Pugazhenthi, 2014). Most of these devices act like end-effector robot, i.e. they provide assistive forces only at one body segment, while the trunk is either rigidly supported by a back support of a seat or through use of the arms. All these approaches may or surely result in unnatural kinematics. The purpose of this Chapter is to discuss solutions of mechatronic design for the control of the actuation of assisting devices designed for the STS, as evolution of the ones developed by the authors (Rea et al., 2013; Rea & Ottaviano 2018). They can be either used as rehabilitation devices, as the one proposed in (Rea et al., 2013). The mechatronic design is particularly important when the motion or force have to be controlled (Figliolini et al., 2010, Borras et al., 2009; Ottaviano et al, 2004). Simulation results are reported to show the feasibility of the proposed solution together an experimental test bed of the mechatronic design. This Chapter reports perspectives on mechatronics integrated in home environment and enhancements and of research activities presented in (Ottaviano et al., 2019) as a paradigmatic case of study.

One of the main challenges in the design of assisting and/or rehabilitation systems is their portability and cost, which are in most of the cases prohibitive, even for the solutions developed and commercially available.

Nevertheless, in the last decades, the cost of electronics and microcontrollers has been decreasing, but software in mechanical products have increased. In addition, trends in new products ranging from mechanical solutions with added functionality realized by electronics and software to electronic products with embedded software with the need of mechanical encapsulation. The multi-technological products pose a fundamental challenge for companies joining development processes, different in nature, into a synergistic process to produce successful products. While some companies see new market potentials in the joining of solutions from several engineering disciplines, other companies sees it as a necessity to stay competitive on already captured market segments. The added complexity caused by going from single- to multi-disciplinary development can have various consequences, bringing potential danger to the project. When designing a new mechatronic product or solution, these issues should be faced.