Terrain Compensation for Off-Road Vehicles Using Inertial Measurements in a Multi-Body System

Equipping a tractor with an inertial measurement unit is common practice to compensate for undulating terrain when the vehicle is standing or driving on a slope. This solution considers the tractor as a single rigid body. Our research evaluates the possibilities of measuring the individual inclination angles of the cabin and the chassis as two connected bodies in a Multi-Body system with two separate inertial measurement units to offer increased positioning precision in terrain compensation. We prove geometrically and experimentally that two IMUs help to accurately determine the tractor's control point, whereas using only one IMU leaves errors of several centimeters. Awareness of the correct position of the cabin's instant center of rotation is vital for the correction precision. Transferring the terrain compensations to dynamic field applications shows reduced positioning deviations on undulating terrain, in curves, and in rapid braking and acceleration situations but requires a holistic system integration of the sensors to increase accuracy.