Suitability of a Three-Axis Inclinometer to the Automated Blade Control System of Excavator

Partly automated blade control of excavator has been studied. Main focus of the study were to find means to control one of the excavator's work cylinders automatically while machine operator controls the rest of non-automated work cylinders. This article concentrates on the suitability of a certain inclinometer sensor for partly automated blade control of excavator. Test device was built where inclinometers output data controlled hydraulic cylinder and the statical and dynamical properties of the cylinder and the controlling sensor were studied. In statical tests the inclinometer was attached to the milling tools distributing board along with the reference sensor. The positioning accuracy and the positioning repeatability were studied with the statical tests. In dynamical tests the inclinometer was attached to the pendulum and the dynamical properties of the inclinometer were researched with the pendulum oscillation experiments. Test device contained angular potentiometer which purpose was to function as inclinometers reference sensor. The LVDT displacement transducer was attached to the side of the cylinder which functioned as cylinders integrated displacement sensors (VRVT) reference sensor. In dynamical tests the inclinometers and reference sensors data responses were measured with different pendulum rod lengths and attachment setups. Centripetal accelerations and angular frequencies were calculated from the measured data and their effects for angular error are introduced. Results indicate that cylinders positioning accuracy was ± 1.5 millimetres and the inclinometers angle accuracy was ± 0.3 angle of degrees with delay of 600 ms. Accuracies are sufficient but the delay is too long for partly automated blade control.