Biomechanics and Design of a Flexible Back-Support Exoskeleton for Versatile Lifting Task Assistance

Manual lifting tasks can put much burden on human musculoskeletal system, especially for the lower back region. To avoid low back injury, proper assistance is desired for workers with different lifting postures and techniques. This paper explores the biomechanics and design of a back-support exoskeleton to provide ergonomic assistance for lifting tasks in different postures, including symmetric and asymmetric lifting. The biomechanical feature of asymmetric lifting is discussed based on a simplified biomechanical model. With the biomechanical analysis, this paper presents a system design with bilateral independent cable force routing and compliant actuation unit, and outlines the control system implementation. Experiments indicate the effectiveness of the flexible system design in guaranteeing wearer's natural range of motion with a minimum of below 5% restriction and the capability of delivering desired assistance to asymmetric lifting postures, showing promising performance on providing versatile ergonomic assistance for different manual lifting tasks.