Comparison of three different kinematic sensor assemblies for locomotion study

Abstract

The decrease in the costs of electronic components and devices, conjugated to the advancement of the miniaturization technologies, has promoted a large profusion of the use of motion sensors for human movement analysis in clinics. The errors in the design are numerous, from circuital errors to positioning and orientation errors; a preliminary approach to the problem by means of simulations is necessary. We developed an environment for the simulation of mixed kinematic sensor assemblies with accelerometers and rate gyroscopes; it was tested by means of three different assemblies in the simulation of the trajectory reconstruction. The first assembly was represented by a 6-accelerometer assembly, the second by a 9-accelerometer assembly and the third was based on three rate gyroscopes and three accelerometers. The circuital error, given as an input to the environment, was determined during a bench test, the positioning error was set to pe = 5 × 10−4 m and the orientation error to αe = 6 × 10−2 deg. Results showed the agreement between estimated and experimental data from the bench test. Simulation results also showed that the errors in trajectory reconstruction in the sagittal plane were lower than 3–4% during 4 s of simulation.