Table 2.
Review summary. IF: interaction force, IT: interaction torque, IP: interaction pressure, n.a.: not applicable.
| Author and Ref. | Year | pHEI Metrics | Sensor | Protocol | Device | Sensor Placement |
|---|---|---|---|---|---|---|
| Akyiama et al. [46] | 2012 | IF/support metrics: Normal force, Misalignment |
Load cell 3D motion capture system |
n.a. | Lower limb exoskeleton frame mounted on a dummy leg | Lower leg Upper leg |
| Akyiama et al. [64] | 2015 | IF/support metrics: Normal/Tangential IF, Relative motions |
3-axis Load cell 3D optical motion capture system |
10 sit-to-stand motions | Leg type motor-actuated lower-limb orthosis |
Lower leg Upper leg |
| Akyiama et al. [69] | 2012 | IF/IT/support metrics: Normal/Tangential IF, Interaction moment, Skin slippage, Relative motions |
3-axis Load cell Slip sensor (2D imaging devices) 3D optical motion capture system |
15 sit-to-stand motions | Lower limb physical assistant robot | Upper leg |
| Amigo et al. [48] | 2012 | IF/support metrics: Normal/Tangential IF, Misalignment |
6-axis Load cell Full bridge strain gauges |
Forearm flexion-extension | Arm orthoses | Forearm |
| Awad et al. [70] | 2020 | IF/support metrics: Disturbing force, Adverse event observation, Patient feedback |
Load cell Questionnaire |
20 min of overground walking practice, 20 min of treadmill walking practice |
Lower limb soft exosuits | Not specified |
| Beil et al. [40] | 2018 | IF: Overall 3D IF |
3-axis Load cell | 13 different motion tasks | Lower limb exoskeleton | Upper leg Lower leg |
| Bartenbach et al. [47] | 2015 | IF/support metrics: Overall IF, Misalignments, Perceived discomfort, Physical load |
Load cell 3D optical motion capture system Questionnaire |
2 min of familiarization and 20 s of test on a treadmill |
Lower limb exoskeleton | Lower leg Upper leg |
| Bessler et al. [30] | 2019 | IF/IT: Normal/Tangential IF, Force distribution, Interaction torque |
FSR sensor 3-axis load cell |
Moving forearm along 3 axis | Forearm support | Forearm |
| Choi et al. [19] | 2018 | IF: Normal force |
FSR sensor | Treadmill walking | Hip exoskeleton | Thigh |
| Christensen et al. [43] | 2018 | IF: Normal force |
FSR sensor | n.a. | 3DOF spherical mechanism for shoulder joint exo | Arm Forearm |
| Del-ama et al. [39] | 2011 | IF/IT: Mean interaction force Mean interaction torque (calculated) |
Gauge bridge | 10 min leg swing | Lower limb exoskeleton | Lower leg |
| De Rossi, Lenzi et al. [21] | 2010 | IP: Pressure distribution |
Matrix of optoelectronic sensors | treadmill walk at 4 Km/h in 3 different conditions: “no-assistance” “low-assistance” and “high-assistance” |
Lower limb robotic platform | Upper leg Lower leg |
| Donati, De rossi et al. [9] | 2013 | IF/IP: Average IF, Maximum IF, Maximum IP |
Load cell Matrix of optoelectronic sensors |
Upper limb: Passive arm Active arc Lower limb: Transparent mode Viscous field |
Elbow active orthoses Lower limb robotic platform |
Forearm Upper leg Lower leg |
| Fan et al. [58] | 2013 | IF: Max normal IF, Normal IF |
Airbags sensor | knee extension to 30° and 60° |
Lower limb exoskeleton | Calf |
| Georgarakis et al. [61] | 2018 | IF/IP: Normal/tangential IF range, Max normal/tangential IF, Shear IP range |
3-axis Force sensor | relax or contract the forearm muscles by grasping a handle according to different force pattern |
Upper limb exoskeleton | Forearm |
| Ghonasgi et al. [35] | 2021 | IF: Force distribution |
FSR sensor matrix | Elbow extensions | Upper limb exoskeleton | Upper arm |
| Grosu et al. [22] | 2017 | IF: Normal force |
3-axis Force sensor | n.a. | Lower limb exoskeleton | Hip |
| Hasegawa et al. [23] | 2011 | IP: Pressure distribution |
Active air mat | Arm suspended Arm moving Arm lifting a weight |
Upper limb exoskeleton | Forearm |
| Huang et al. [38] | 2015 | IF: Total normal force over 4 point |
FSR sensor | n.a. | Upper limb power-assist robotic exoskeleton | Forearm |
| Huysamen et al. [68] | 2018 | IP/support metrics: Maximum pressure, Local perceived pressure, Subjective usability |
Pressure mat Questionnaires |
Lifting a load from the ground, with/without device, with/without load | Back powered exoskeleton | Shoulder Hip/lower back Thigh |
| Islam et al. [33] | 2019 | IF: Normal force variation |
FSR sensor band | Arm liftingh with different payloads | Passive arm exoskeleton | Upper arm |
| Ito et al. [24] | 2018 | IF: Force distribution |
Tactile sensor | n.a. | Wearable robot for upper limb | Upper arm |
| Kim et al. [57] | 2013 | IF: Average normal IF |
Load cell | Walking on a mat | Prototype lower limb exoskeleton | Shank |
| Kim et al. [31] | 2021 | IP/support metrics: Maximum pressure, Average normalized IP, Misalignment |
Air-bladder pressure sensor 3D optical motion capture system |
Knee flexion-extension using a pulling cable attached to the foot | Lower limb exoskeleton | Shank |
| Langlois et al. [18] | 2020 | IF/IP/support metrics: Normal IF, Strapping pressure, Relative motions, Energy dissipation, Perceived comfort |
Air cushion 3D optical motion capture system Visual analog scale |
randomly chosen motions at 5 different inflation pressure | 7 DOF robotic manipulator | Arm |
| Langlois et al. [32] | 2021 | IP: Pressure distribution |
3D printed capacitive sensor pads | Lifting weights with arm straight | Upper arm interface | Arm |
| Leal-junior et al. [26] | 2018 | IT: Lifting torque |
Optical fiber sensor Potentiometer |
Free knee flexion and extension | Lower limb exoskeleton | Shank |
| Leal-junior et al. [27] | 2018 | IF: Normal force |
Optical fiber sensor (Bragg) | Free knee flexion and extension | Lower limb exoskeleton | Shank |
| Leal-junior et al. [36] | 2019 | IF: Normal force |
Optical fiber sensor Load cell |
Free knee flexion and extension | Lower limb exoskeleton | Calf |
| Lee et al. [41] | 2014 | IF: Normal/Tangential IF |
Load cell | Arm lifting at different load conditions | Upper limb exoskeleton | Handle |
| Lenzi et al. [20] | 2011 | IP: Normal IP, Pression distribution |
Matrix of optoelectronic sensors | 1. leaving arm passive; 2. moving faster (higher frequency) than the robot; 3. moving slower than the robot; 4. imposing higher flexion angle than the robot; 5. imposing a higher extension angle than the robot. |
Elbow active orthoses | Forearm |
| Levesque et al. [42] | 2017 | IF: Force distribution |
FSR matrix sensor FSR sensor |
legged deep squats, lunges, as well as stair climb and descent | Lower limb exoskeleton | Thigh Knee Tibia |
| Li et al. [44] | 2019 | IF/IT: 3-D IF, Normalized IF over 3-axis, 3-D IT, Normalized IT over 3-axis |
6-axis Load cell | Walking on treadmill | Prototype lower limb exoskeleton | Upper limb Lower limb |
| Lobo-prat et al. [54] | 2016 | IF/support metrics: Average normal IF, Comfort |
Load cell EMG Questionnaire |
Elbow flexion-extension movements against gravity |
Passive upper limb support | Handle |
| Long et al. [34] | 2017 | IT: Interaction torque |
Elastic band | Leg swings in the air | Lower limb exoskeleton | Thigh and calf |
| Long et al. [49] | 2017 |
IP: Contact pressure |
Pneumatic gas-bag | 40 m walk with (1) passive exo, (2) active exo without gravity compensation, (3) active exo with gravity compensation | Lower limb exoskeleton | Upper leg Lower leg |
| Long et al. [63] | 2018 | IT: Interaction torque |
Torque sensor | Natural speed of about 0.8 m/s and the maximum velocity up to 4 km/h with 30 kg loads | Lower limb exoskeleton | Knee |
| Mahdavian et al. [37] | 2015 | IF: Normal IF |
Strain gauges | n.a. | Prototype upper limb exoskeleton | Elbow |
| Masud et al. [50] | 2021 | IF/(IT) Module magnitude of normal IF, Calculated IT |
6-axis Load cell | n.a. | Arm exoskeleton | Lower arm |
| Muozo et al. [65] | 2020 | IT: Bending torque |
Load cell 3D optical motion capture system |
Normal walking with locked Orthotic knee and actuated Orthotic knee | Leg orthoses | Knee |
| Quinlivan et al. [66] | 2015 | IP: Pressure distribution |
Pressure mat | n.a. | Soft exosuit | Thigh Hip Belly |
| Rathore et al. [59] | 2016 | IF: Maximum normal IF |
FSR sensor | two steps forward (a full gait cycle) |
Lower limb exoskeleton | Thigh braces Leg braces |
| Schiele et al. [45] | 2010 | IF/IT/IP/support metrics: Mean absolute normal IF, Mean absolute IT, Fixation cuff IP, Tracking error, Subjective comfort and workload, Misalignments |
6-axis Load cell Pressure interface Questionnaire |
visually track a random target on a screen | Upper limb exoskeleton | Forearm |
| Tamez-Duque J. et al. [25] | 2015 | IP: Normal pressure, Pressure distribution |
FSR pressure pad | sit to stand, walk forward, turn 180° to the right, turn 180° to the left, stand to sit |
Lower limb exoskeleton | Upper leg Lower leg |
| Tran et al. [62] | 2014 | IT: Interaction torque |
Torque sensor Inclinometer |
n.a. | Lower limb exoskeleton | Knee |
| Tran et al. [51] | 2021 | IF/IT: Normal IF, Performance index: normalized square sum of the sagittal plane IF |
2-axis Force sensor | n.a. | Lower limb exoskeleton | Thigh Shank |
| Wan et al. [56] | 2020 | IF/IP/support metrics: Average normalized IF (normal + shear), Maximum shear stress, Human-cuff relative motion, Cuff slip velocity |
3-axis Force sensor Laser mouse sensor |
Walking on treadmill | Custom-made lower limb exoskeleton | Thigh Calf |
| Wang et al. [55] | 2020 | IF/IP/support metrics: Average normal force, Maximum normal pressure, Comfort |
FSR sensor Questionnaire |
10 repetitions of sit-to-stand, standing for 10 min, walking for 10 m, and stand-to-sit | Lower limb exoskeleton | Shin Hands |
| Wang et al. [28] | 2021 | IF: Overall IF |
Soft pneumatic force sensor | Walking on treadmill | Hip exoskeleton | Thigh |
| Wilcox et al. [60] | 2016 | IF: Average peak force |
FSR sensor EMG |
Two steps forward Two steps backward Two sidesteps |
Lower limb exoskeleton | Thigh Lower leg |
| Wilkening et al. [29] | 2016 | IF/IT/IP Normal IF Interaction torque Normal pressure |
Pneumatic pad 6-axis Load cell |
n.a | Forearm interface | Forearm |
| Xiloyannis et al. [67] | 2018 | IF/IT/IP Normal IF Interaction torque, Pressure distribution, Pressure peak |
Pressure pad | Three flexion/extension movements between 0° and 90° | Elbow exosuit | Elbow |
| Yousaf et al. [52] | 2021 | IF: Normal distribution, Average RMS normal distribution |
6-axis Load cell FSRs |
n.a. | Upper arm exoskeleton interface | Arm |
| Zanotto et al. [53] | 2015 | IF/IT: Average normal IF, RMS normal IF, Average IT |
6-axis Load cell Potentiometric goniometer |
Treadmill walking in inertia, velocity, and alignment conditions | Treadmill-based exoskeleton | Thigh Shank |