Evaluation of a New Simplified Inertial Sensor Method against Electrogoniometer for Measuring Wrist Motion in Occupational Studies

Abstract

Wrist velocity is an important risk factor for work-related musculoskeletal disorders in the elbow/hand, which is also difficult to assess by observation or self-reports. This study aimed to evaluate a new convenient and low-cost inertial measurement unit (IMU)-based method using gyroscope signals against an electrogoniometer for measuring wrist flexion velocity. Twelve participants performed standard wrist movements and simulated work tasks while equipped with both systems. Two computational algorithms for the IMU-based system, i.e., IMUnorm and IMUflex, were used. For wrist flexion/extension, the mean absolute errors (MAEs) of median wrist flexion velocity compared to the goniometer were <10.1°/s for IMUnorm and <4.1°/s for IMUflex. During wrist deviation and pronation/supination, all methods showed errors, where the IMUnorm method had the largest overestimations. For simulated work tasks, the IMUflex method had small bias and better accuracy than the IMUnorm method compared to the goniometer, with the MAEs of median wrist flexion velocity <5.8°/s. The results suggest that the IMU-based method can be considered as a convenient method to assess wrist motion for occupational studies or ergonomic evaluations for the design of workstations and tools by both researchers and practitioners, and the IMUflex method is preferred. Future studies need to examine algorithms to further improve the accuracy of the IMU-based method in tasks of larger variations, as well as easy calibration procedures.

Ratings of Hand Activity and Force Levels among Women and Men Who Perform Identical Hand-Intensive Work Tasks

“…With today’s developments, there are easy-to-use technical methods for research and field studies. In the future, the use of such methods [ 43 ], together with scientifically based action levels [ 44 ], should be considered. The current finding of worker gender-related differences in estimates is another reason to consider the use of objective methods.…”

Wearable Motion Capture Devices for the Prevention of Work-Related Musculoskeletal Disorders in Ergonomics—An Overview of Current Applications, Challenges, and Future Opportunities

“…As shown in Table 3, IMUs are increasingly being used for kinematic measurements of the arms and trunk [69,116], while twin-axis goniometers (electrogoniometers) still seem to dominate kinematics measurements of the wrist [46,117].…”

“…The generalizability of such conversion equations to multiple occupational groups is yet to be tested; hence, more research is needed. As shown in Table 3, IMUs are increasingly being used for kinematic measurements of the arms and trunk [69,116], while twin-axis goniometers (electrogoniometers) still seem to dominate kinematics measurements of the wrist [46,117].…”

“…Recently, IMUs have been introduced and evaluated against twin-axis electrical goniometers for recording wrist velocities in simulated work showing promising results with close correspondence both for standardized flexion/extension movements (correlation close to one and less than 10% difference in the 50th and 90th percentiles, and in three simulated work tasks with mean differences below 10%) [117]. Only the gyroscope data was used in the velocity computations, and there was no magnetic field dependence.…”

Predicting Wrist Posture during Occupational Tasks Using Inertial Sensors and Convolutional Neural Networks

“…Peppoloni et al successfully demonstrated such a system, however, the use of EMG further compounds the procedural difficulty of usage in the workplace [ 18 ]. While challenges exist in the direct measurement of wrist kinematics with IMUs, one alternative is to assess metrics other than joint angle such as joint angular velocity, which can be directly measured using gyroscopes placed across the joint as demonstrated by Manivasagam and Yang [ 19 ]. This approach offers a much more practical approach to extracting data, however, from a practical standpoint it is still very much the domain of research.…”