Table 3.

Overview of the analyzed devices. The * indicates commercial availability. Power indicates the maximum assistive torque [Nm]. Listed DoFs are both actuated (A-DoF), counted unilaterally (#), and non-actuated (N-DoF). Corresponding humans joint DoFs are flexion-extension ($\alpha$) and adduction-abduction ($\beta$). Sensors and control data are reported only where available.

Device Name	f	Assisted Task(s)	Actuation	Power	A-DoF	(#)	N-DoF	Sensors	Control
SPEXOR * [15]	6	Static forward bending Load lifting Repetitive lifting	Passive	25 Nm	$\alpha$-Hip $\alpha$-L5-S1	(2)
Laevo * [18]	6	Static forward bending Load lifting Load carrying Precision manual assembly	Passive		$\alpha$-Hip	(1)
HAL * [19]	2	Stoop load lifting Load lifting	Active	30 Nm	$\alpha$-Hip	(1)		EMG Angle sensors	Hybrid EMG + Inclination (CVC + CAC)
BackX AC * [20]	1	Precision manual assembly	Passive		$\alpha$-Hip	(1)
Robo-Mate [21]	1	Load lifting	Active	40 Nm	$\alpha$-Hip	(1)		EMG IMU	EMG threshold; Inclination angle Hybrid EMG + IMU
APO [22]	1	Load lifting	Hybrid	35 Nm	$\alpha$-Hip	(1)	$\beta$-Hip	Joint encoders	$\alpha$-Hip-dependent torque profile
‘Active industrial exo’ [23]	1	Load lifting Dynamic load handling	Active	40 Nm	$\alpha$-Hip	(1)		Inclination sensor	Torque $\propto sin(\alpha -\mathsf{Hip})$
MeBot-EXO [24]	1	Static forward bending Semi-squat lifting	Active	160 Nm	$\alpha$-Hip	(1)		KinematicsInteraction force	$\dot{\alpha }$-Hip torque control w/interaction force minim.
‘Lower-limbexoskeleton’ [17]	1	Squat load lifting Load carrying	Active	76 Nm	$\alpha$-Hip $\alpha$-Knee	(2)	$\alpha$-Ankle $\beta$-Ankle	Torque sensors Joint encoders GRF sensors	(Human torque amplification (estimated by Kalman Filter)
‘Lifting Assist Device (LAD)’ [16]	1	Load lifting	Hybrid		$\alpha$-Hip $\alpha$-L5-S1	(2)	$\beta$-Hip $\beta$-L5-S1	IMU Potentiometers	Pre-defined force profiles (State machine)
‘Passive spine exoskeleton’ [25]	1	Dynamic bending Static forward bending	Passive	30 Nm	$\alpha$-Hip	(1)
‘Lower extremity exoskeleton’ [26]	1	Load lifting	Passive		$\alpha$-Hip	(1)

Abbreviations: DoF, Degree of Freedom; EMG, ElectroMyoGraphy; IMU, Inertial Measurement Unit; GRF, Ground Reaction Force; L5-S1, lumbo-sacral joint.