Dynamic inclination estimation with liquid based sensors

In cases where mobile robots lift weights they may turn over due to overload. Such an event may be harmful to the robot or worse to people working with it. The maximum allowable load depends on the lever arm, the weight and the inclination of the arm. Knowledge of these three factors allows to prevent the robot from lifting weights beyond the limit for stability. For this purpose inclination sensors are required. Sensors based on liquid level measurement provide high accuracy which is desired for this task. However during motion the liquid lags behind the true position due to filtering of signals, friction, adhesion on the surface and the viscosity of the fluid. Furthermore shocks may lead to distortions of the liquid distribution for short periods. In this paper an adaptive approach is presented, which provides significant reduction of this undesired behavior of the sensor.