Passive Exosuit Emulator for Material Handling Applications

The letter introduces a passive back-assist exosuit (BASE) emulator system for manual material handling applications. The presented emulator has a fabric brace mounted modular moment arm, onboard load cells for measuring device interaction forces, and a synchronized EMG system. The design permits studies for experimenting with different elastic elements and their routing and moment arm configuration to establish biomechanical and physiological understanding before exosuits development. Human trials were conducted to demonstrate the usability of the presented emulator during the lifting/lowering task. Three different moment arm configurations (C1, C2, and C3) were tested for their effect on the muscle activity, device-to-body forces, and perceived discomfort during a lifting/lowering task. The configuration C2 was found to produce the least device-to-body forces (at shoulder and waist). While the maximum reduction of 16.7% in erecter spine muscle activity was observed for C3 configuration compared to when no Exosuit was used. The emulator could be used to understand biomechanics for different exosuit configurations during manual handling tasks. The understanding from the emulator will aid the development of future passive back assist devices for rehabilitation and occupational use.

I. Introduction

Despite automation, many industrial settings require manual material handling (MMH) tasks to be performed by individuals. The reason lies in human capabilities to adapt to continuously varying products, environments or tasks that require agile decisions at workplaces. However, such tasks expose the workers/individuals to physical workloads due to load handling, repetitive movements, and awkward postures [1]. It has been estimated that around 60–80% of people have suffered low back injuries at the workplaces [2]. Moreover, back and shoulder pain are regarded as the main factor affecting the working population, wherein mechanical loading has been considered a primary factor contributing to lower back pain (LBP) and reduced productivity at workplaces [3]. Over time, the MMH tasks expose an individual to the associated risks of developing work-related musculoskeletal disorders (WMSDs), imposing a significant burden on the health care system and causing decreased labour productivities [3], [4]. Hence, modern industries are looking for possible ways to efficiently incorporate wearable assistive devices for MMH tasks.