*2.1. Task Description*

Considering the industrial context, the main purpose of the proposed exoskeleton is to relieve the human from lifting efforts of heavy parts, while actively assisting him/her during the task.

In order to design the proposed exoskeleton, a bumper lifting task in a car assembly line (Figure 1a) has been considered as the reference task. Such task implies a target payload for the upper limbs exoskeleton equal to *Pe* = 10 kg (i.e., each exoskeleton arm has to lift—in ideal conditions—*Pa* = 5 kg).

In the following, the task is analyzed in order to define the exoskeleton configurations assumed during the task execution. Two main configurations will be assumed by the human wearing the exoskeleton during reference task (Figure 1b):


**Figure 1.** (**a**) Reference task: car bumper lifting and transportation. (**b**) Human arm + exoskeleton configurations during task execution.

More in details, the task is composed of nine phases (Figure 2):


**Figure 2.** Lifting task phases.

## *2.2. Exoskeleton Specifications*

In order to design the exoskeleton to face the proposed task, the following requirements have to be considered:

