System flowchart
Human-Body Displacement Estimation Based on Wearable Inertial Sensors Motion Capture

In recent years, with the advancement of technologies such as the Internet of Things and micro-sensors, inertial sensor motion capture systems that are small in size, inexpensive, unlimited movement space, and no occlusion problems have become more and more popular. However, the displacement estimated from the inertial sensors will become increasingly inaccurate as error accumulates. Therefore, how to correct or suppress the accumulation of errors, long-term use of inertial sensors has become an important issue.
We aim to develop an innovative motion capture algorithm for wearable inertial sensors. Our algorithm captures motion data through 14 nine-axis inertial sensors, and estimates the displacement of each key parts of human body based on biomechanical model. We also designed 4 calibration poses to improve the accuracy of spatial positioning. We additionally present a Biomechanical-Sensor (BS) hybrid algorithm that combines the sensor trajectory with the final position point of the biomechanical model to compensate for the displacement error of the final position point. Such error is caused by the accumulation of sensor errors along with the biomechanical model trajectory error caused by human soft tissue. In this study, the subjects wore the devices from optical system and inertial sensor system at the same time and performed motions. The two systems separately estimate the displacement of each part of the human body. Usvally the optical system data is an order of maqnitude more accurate than that of inertial sensor data. We use optical system data as the standard to verify that our algorithm can effectively improve the estimated displacement accuracy using inertial sensors.

SUMMARY (中文總結):
近年來隨著物聯網(Internet of Things)、微型傳感器等技術的進步,體積較小、價格便宜、運動空間較不受限、無遮蔽問題的慣性傳感器動態捕捉系統則越來越受到歡迎。但由於慣性傳感器原始數據所估算的位移,會隨著誤差的累積越來越不精準。所以如何修正或抑制其誤差的累積,長時間的使用慣性傳感器成為了一個重要的課題。


  • The motion of continuous punching


Displacement trajectory diagram of first punching of continuous punching.

Displacement trajectory diagram of second punching of continuous punching.

Displacement trajectory diagram of third punching of continuous punching.