Table 2.
Conventional actuators used in lower/upper limb exoskeletons.
| Reference/Year | Actuator Type | Location/Purpose | Weight (g) | Power (W) | Torque/Force |
|---|---|---|---|---|---|
| Takamitsu et al. [153]/2009 | Pneumatic | Upper limb/Elbow, shoulder, and waist support | 5800 (entire exoskeleton) | N/A | Elbow & Shoulder 45 Nm Waist 90 Nm |
| Akdoğan and Adli [148]/2011 | Servo motor | Lower limb/Rehabilitation | 1600 | 570 | 1.15 Nm (stall) |
| Inose et al. [161]/2017 | Pneumatic | Upper limb/back support | 2900 (entire exoskeleton) | N/A | 350 N @ 60 kPa |
| Zhang et al. [144]/2018 | BLDC motor | Lower limb/Walking assistance | 600 | 90 | 0.44 Nm |
| Pirjade et al. [162]/2020 | DC motor | Lower limb/Hip and knee support | 210 | 100 | 1 Nm (peak) 0.02 Nm (rated) |
| Bouteraa et al. [150]/2020 | Servo motor | Upper limb/Elbow support for rehabilitation | 152 | 36 | 2.4 Nm (stall) |
| Mahdavian et al. [147]/2020 | Stepper motor | Upper limb/Arm support for rehabilitation | 470 | 24 | 1.85 Nm (stall) |
| Lee et al. [145]/2021 | BLDC motor | Lower limb/Ankle support | 242 | 75 | 0.11 Nm |
| Sun et al. [152]/2021 | Hydraulic | Lower limb/Walking assistance | 2500 | N/A | 1700 N @ 18 MPa (with 4 actuators) |
| González-Mendoza et al. [149]/2022 | Servo motor | Upper limb/Elbow support | 153 | 93 | 1.68 Nm (rated) 8 Nm (stall) 20 N (axial) |
| Servo motor | Upper limb/Wrist support | 55 | 8 | 1.47 Nm (Stall) | |
| Fang et al. [151]/2023 | Stepper motor | Lower limb/Hip support for walking assistance | 320 | 60 | 13 Nm (stall) |
| Stepper motor | Lower limb/Knee and ankle support for walking assistance | 320 | 55 | 6.5 Nm (stall) | |
| Zhao et al. [163]/2023 | Hydraulic | Lower limb/Knee support | 1400 (without fluids) | N/A | 160 N @ 60 kPa |
| Fan et al. [164]/2024 | Hydraulic | Lower limb/Waking assistance with extra loads | 4750 (actuator components) | N/A | 237 N @ 2.5 MPa |
| Miškovic et al. [160]/2024 | Pneumatic | Lower limb/Knee support | 760 (without mechanical parts) | N/A | 15.94 Nm @ 800 kPa |