Saskia Baltrusch

145 Chapter 5 cost of a reduced range of motion by 24.5° and an angle discrepancy between the exoskeleton of up to 50%. Further research is needed, to investigate, if good angle agreement can also be achieved with higher support torques from a flexible structure. A comparison to the Laevo device with functional outcomes draw an encouraging picture. Especially big is the difference when asked to rate the interference of tasks by the devices. While the interference with the described prototype is perceived as low as 1.7 cm on the VAS scale, the Laevo almost doubles this value with 3.4 cm (Figure 12A). Note, a value of 0 cm means no interference and a value of 10 cm means a high interference. The device is perceived to especially simplify the task of forward bending during a manual task and bending the trunk forward as much as possible, with extended knees. On the other hand walking seems to become more difficult. This is not surprising, because in a passive device, the user has to work against the device while pushing the leg forward. A clutch mechanism, that engages the hip torque source during a lifting task and disengages is during walking, stair climbing etc. is already under development. A purely passive clutch mechanism of this kind has been integrated in the BackX exoskeleton. However, no studies or data could be found, that investigate how well this mechanism works and how its function is perceived by the user. Limitations The number of subjects for the functional tests (N = 3) is small, especially considering the subjective nature of these tests. This means, that generalizations of the functional testing results should be interpreted with caution. Nonetheless should be noted, that for this small group of participants consistent and perceivable improvements compared to the Laevo exoskeleton were reported by the participants. 6 Conclusions A passive novel back support exoskeleton was presented, which allows for a large range of motion while wearing it. At the same time support torques of up to 25 Nm are provided at the lower back. Good kinematic agreement, resulting from the misalignment compensation mechanisms at the trunk and hip level minimize 5