Table 2 An overview on the classification of soft actuators based on the review methodology

EMG controlled robotic finger for grasping

Dynamixel motor

Rotatable and flexi ble

3D printed ABS(Acrylonitrile Butadiene Styrene, ABSPlus, Stratasys, USA) and 3D printed thermoplastic polyurethane (Lulzbot, USA) for flexible joint

Dynamixel servo AX12-A (Robotis, South Korea) -motor for actuation

Rotatable locking mechanism to ensure grasp compensation

[17]

Vibration assistance with prosthetic limbs during post-stroke re habilitation

Vibration motor

Hard and robust

N/A

Precision Microdrives 306-109 with 3.5G and 12,000rpm, Pico Vibe\(^{\textrm{TM}}\) 10mm

Creates vibratory stimulation

[18, 32]

Ankle impairments for post stroke sub jects

Electric motor driv ing the pully for ac tuation

Rigid plastic

VeroBlack Plus, Stratasys

Gears and a rotary en coder (MX-64T, ROBO TIS),1226A012B K1855, Faulhaber, Germany and EC-4pole 2290W, Maxon Inc, USA

Generates desired pulling forces

[26, 28, 33, 34]

EMS based hand and foot dexterity

EMS electrodes for actuation

Muscle attachment with flexible wiring

N/A

Medically approved EMS gen erator

Wrist rotations, fin ger flexion and exten sion

[29, 35, 36]

Hand rehabilitation

Pneumatic actuators

Flexible, less stiff

N/A

Electropneumatic components fabrication

Flexion and exten sion

[19, 37,38,39,40]

Hand rehabilitation and assistance

Pneumatic actuators

Flexible and fabri cated type with full bending

Thermoplastic polyurethane (TPU)-coated fabrics

A neoprenesponge (733-6731, RS Components, Singapore)

Sheet-like rubber muscles achieves full bending motion

[41]

Development of hap tic feedback

Electromagnetic ac tuators

Flexible and rigid

Fabricated with 3D printed hol low cylinders and rubber like sheet material

N/A

Bistable nature

[42]

Preliminary assess ment on the develop ment of hand glove

Pneumatic actuators

Flexible

N/A

N/A

Increases pressures using customized force measurement system

[43]

Development of hap tic feedback

Piezo-electric actua tors

N/A

T-ZnO nanowire textiles

N/A

N/A

[44, 45]

Deep-sea explo ration

Electromechanical actuators

Linear and rotatory

N/A

N/A

N/A

[46]

Finger dexterity training

Voice coil actuators

Rigid, non compliant structure

Actuator made of Magnetorhe ological fluid (MR)

VCA, Dayton Audio DAEX9- 4SM

Provide wide range of vibrotactile force

[47, 48]

Evaluation of haptic sleeve

Pneumatic actuators

Elastic and rigid

Fluid fabric muscle sheets

N/A

Inverse pneumatic ar tificial muscles and eliminates unwanted parasitic forces

[27, 49]

Teleoperation based augmentation

Phantom haptic actu ation

Hard and rigid

Phantom haptic Device, 4 3D cameras (3 Kinect v1 and 1 Kinect v2)

N/A

N/A

[50]