Musculoskeletal disorders are common occupational diseases that have become a major social problem. Mechanization has been promoted as a solution to this problem. However, several tasks still require manual labor, such as fruit harvesting in orchards, making the introduction of machinery difficult in many cases. Recently, from the viewpoint of worker protection and ergonomics, various wearable robots for work support have attracted attention. In Europe and the US, there has been much development of arm-lifting assistive devices that support upward work while holding tools in the hands for industrial applications. However, most of the devices currently on the market are expensive compared to their assistive capabilities. Against this background, we developed three types of arm-lifting assistive devices with different concepts (an exoskeleton arm-lifting assistive device utilizing a gas spring, an exoskeleton arm-lifting assistive device utilizing McKibben-type artificial muscles, and an arm-lifting assistive suit utilizing rubber) to develop inexpensive, high-power devices. Furthermore, comparative verification of the assist effectiveness of each device was conducted.

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