IMU-based mounting parameter estimation on construction vehicles

This study reports on a method for parameter estimation of a randomly placed inertial measurement unit (IMU) on an excavator arm. Cost and time can be saved if the sensing equipment is self-calibrating and the mounting position is not a strict requirement. A sensor kit could be mounted on an autonomous construction vehicle — an excavator or front loader, for instance — and calibrate by itself. Automatic recalibration improves accuracy error over lifetime caused by sensor ageing, for instance. Inertial sensors are small, cheap and can endure harsh environments better compared to other sensors that measure position and configuration of a hydraulic arm. An IMU containing 3D gyroscopes and accelerometers can measure the absolute angle according to the Earth coordinate system with suitable algorithms, and can estimate the relative arm segment angles and the distances from the rotation axes.