Table 4.
Listing of published inertial measurement unit (IMU)-based joint monitoring techniques, analysis and validation methods.
| Ref. | Year | Sensor Units and Module | Sampling Frequency | Wireless | Analysis (Joint) | Reference System and Validation |
|---|---|---|---|---|---|---|
| [64] | 2008 | 2 (gyroscope + accelerometer) | 240 Hz | No | Knee angle (3D) | Magnetic motion capture system RMS errors: 4° (flexion/extension) 5° (abduction/adduction) 10° (internal/external Rotation) |
| [68] | 2009 | 2 (gyroscope + accelerometer) | 240 Hz | No | Knee angle (3D) | Visual aligned IMU system Accuracy: between 4.0° and 8.1° |
| [63] | 2011 | 2 (Gyroscope + Accelerometer + Magnetometer) | 5 Hz | Yes | Knee angle | Infrared motion capture system Average deviation: 0.08° to 3.06° |
| [69] | 2013 | 4 (gyroscope + accelerometer + magnetometer) | 120 Hz | Yes | Knee angle for both prosthesis and the contralateral leg | Optical 3D motion capture system RMS errors: <0.6° (Prosthesis) <4.0° (Contralateral leg) |
| [70] | 2013 | 2 (gyroscope + accelerometer + magnetometer) | 128 Hz | Yes | Elbow, forearm and shoulder movement | Optical tracking system RMS errors: 6.5° (Elbow flexion/extension) 5.5° (Forearm supination/pronation) 5.5° (Shoulder flexion/extension) 4.4° (Shoulder abduction/adduction) |
| [74] | 2013 | 2 (gyroscope + accelerometer + magnetometer) | Not mentioned | Yes | Knees, elbows, toes, hip, shoulder, wrist, ankle, neck, forearm and thumb joints | Not mentioned |
| [62] | 2014 | 4 (gyroscope + accelerometer + magnetometer) | 120 Hz | Yes | Knee angle for both prosthesis and the contralateral leg | Optical 3D motion capture system RMS errors: <1.0° (Prosthesis) <3.0° (Contralateral leg) |
| [71] | 2015 | 3 (gyroscope + accelerometer + magnetometer) | 10–100 Hz | Not mentioned | Hip and knee joint tracking |
Optical tracking system RMS error: <3.0° |
| [67] | 2016 | 4 (gyroscope + accelerometer + magnetometer) | 50 Hz | Not mentioned | Gait analysis by monitoring hip, knee and ankle joints | A computer mathematical simulation, a universal goniometer system and a real gait test max RMS error: 1.70° |
| [82] | 2016 | 4 (gyroscope + accelerometer) | 40 Hz | Yes | Knee angle for estimating human movement | Goniometer-based system highest angle deviation: 2.0° |
| [72] | 2016 | 1 (Gyroscope + Accelerometer) | 100 Hz | Not mentioned | Hip and knee angles | A stereophotogrammetrical system RMS error: <3.2° |
| [66] | 2017 | 2 (gyroscope + accelerometer + magnetometer) | 30 Hz | No | Knee angle for human gait analysis | A vision-based motion capture system high correlation between two measurements (>0.947) |
| [65] | 2017 | 2 (gyroscope + accelerometer) | 128 Hz | Not mentioned | Knee angle, heel-strike and toe-off events for gait analysis | A commercial motion capture software RMS error: 8.0° |
| [73] | 2017 | 2 (gyroscope + accelerometer) | 30 Hz | Yes | Validation of a knee angle measurement | A DARwIn OP robot as ground truth system for knee angle measurement RMS error: <6.0° (When robot was walking) <5.0° (When robot kept the left leg stretched and performed an angle of −30°) |