RepoIMU T-stick

The RepoIMU T-stick is a small, low-cost, and high-performance inertial measurement unit (IMU) that can be used for a wide range of applications. The RepoIMU T-stick is a 9-axis IMU that measures the acceleration, angular velocity, and magnetic field. This database contains two separate sets of experiments recorded with a T-stick and a pendulum. A total of 29 trials were collected on the T-stick, and each trial lasted approximately 90 seconds. As the name suggests, the IMU is attached to a T-shaped stick equipped with six reflective markers. Each experiment consists of slow or fast rotation around a principal sensor axis or translation along a principal sensor axis. In this scenario, the data from the Vicon Nexus OMC system and the XSens MTi IMU are synchronized and provided at a frequency of 100 Hz. The authors clearly state that the IMU coordinate system and the ground trace are not aligned and propose a method to compensate for one of the two required rotations based on quaternion averaging. Unfortunately, some experiments contain gyroscope clipping and ground tracking, which significantly affect the obtained errors. Therefore, careful pre-processing and removal of some trials should be considered when using the dataset to evaluate the model's accuracy.

RepoIMU T-pendulum

The second part of the RepoIMU dataset contains data from a triple pendulum on which the IMUs are mounted. Measurement data is provided at 90 Hz or 166 Hz. However, the IMU data contains duplicate samples. This is usually the result of artificial sampling or transmission problems where missed samples are replaced by duplicating the last sample received, effectively reducing the sampling rate. The sampling rate achieved when discarding frequent samples is about 25 Hz and 48 Hz for the accelerometer and gyroscope, respectively. Due to this issue, it is not recommended to use this database for model training and evaluation. Due to this fact, we cannot recommend using pendulum tests to evaluate the accuracy of IOE with high precision.