An active back-support exoskeleton to reduce spinal loads: actuation and control strategies

Wearable exoskeletons promise to make an impact on many people by substituting or complementing human capabilities. There has been increasing interest in using these devices to reduce the physical loads and the risk of musculoskeletal disorders for industrial workers. The interest is reflected by a rapidly expanding landscape of research prototypes as well as commercially available solutions. The potential of active exoskeletons to reduce the physical loads is considered to be greater compared to passive ones, but their present use and diffusion is still limited. This thesis aims at exploring and addressing two key technological challenges to advance the development of active exoskeletons, namely actuators and control strategies, with focus on their adoption outside laboratory settings and in real-life applications. The research work is specifically applied to a back-support exoskeleton designed to assist repeated manual handling of heavy objects. However, an attempt is made to generalise the findings to a broader range of applications. Actuators are the defining component of active exoskeletons. The greater the required forces and performance, the heavier and more expensive actuators become. The design rationale for a parallel-elastic actuator (PEA) is proposed to make better use of the motor operating range in the target task, characterized by asymmetrical torque requirements (i.e. large static loads). This leads to improved dynamic performance as captured by the proposed simplified model and measures, which are associated to user comfort and are thus considered to promote user acceptance in the workplace. The superior versatility of active exoskeletons lies in their potential to adapt to varying task conditions and to implement different assistive strategies for different tasks. In this respect, an open challenge is represented by the compromise between minimally obtrusive, cost-effective hardware interfaces and extracting meaningful information on user intent resulting in intuitive use. This thesis attempts to exploit the versatility of the active back-support exoskeleton by exploring the implementation of different assistive strategies. The strategies use combinations of user posture and muscular activity to modulate the forces generated by the exoskeleton. The adoption of exoskeletons in the workplace is encouraged first of all by evidence of their physical effectiveness. The thesis thus complements the core contributions with a description of the methods for the biomechanical validation. The preliminary findings are in line with previous literature on comparable devices and encourage further work on the technical development as well as on more accurate and specific validation

Robotic design and modelling of medical lower extremity exoskeletons

This study aims to explain the development of the robotic Lower Extremity Exoskeleton (LEE) systems between 1960 and 2019 in chronological order. The scans performed in the exoskeleton system’s design have shown that a modeling program, such as AnyBody, and OpenSim, should be used first to observe the design and software animation, followed by the mechanical development of the system using sensors and motors. Also, the use of OpenSim and AnyBody musculoskeletal system software has been proven to play an essential role in designing the human-exoskeleton by eliminating the high costs and risks of the mechanical designs. Furthermore, these modeling systems can enable rapid optimization of the LEE design by detecting the forces and torques falling on the human muscles

The Research on Soft Pneumatic Actuators in Italy: Design Solutions and Applications

Interest in soft actuators has increased enormously in the last 10 years. Thanks to their compliance and flexibility, they are suitable to be employed to actuate devices that must safely interact with humans or delicate objects or to actuate bio-inspired robots able to move in hostile environments. This paper reviews the research on soft pneumatic actuators conducted in Italy, focusing on mechanical design, analytical modeling, and possible application. A classification based on the geometry is proposed, since a wide set of architectures and manufacturing solutions are available. This aspect is confirmed by the extent of scenarios in which researchers take advantage of such systems’ improved flexibility and functionality. Several applications regarding bio-robotics, bioengineering, wearable devices, and more are presented and discussed