Apparatus and a method for height control for a dozer blade

摘要

Automatic height control of a dozer blade, the input from the slow absolute height sensor is combined with an input from a gyroscope that measures the instant rotation and recalculates it into a vertical height change using the length of the supporting arms. The combination obtains the accuracy of the absolute height information and an increased speed of measurement resulting in a compensated height estimate that is input to a hydraulic control system of the feedback type. This enables much more aggressive control even though the hydraulic system has an unknown linearity and delay associated with it. The gyroscopic sensor forms an IMU with one degree of freedom to compensate for drawbacks of the absolute height sensor with regard to delay, noise and update rate to obtain a frequent, time-correct height position with a reduced level of noise by means of a calculation based on both types of sensor output.

主权项

1. An apparatus for controlling in a closed loop the height of a front mounted blade on earth moving equipment, comprising:
said front mounted blade forming an aggregate with a pair of supporting arms connected to a body of the earth moving equipment at pivot points and rotated in planes perpendicular to a connecting line between said pivot points by means of hydraulic cylinders supplied via valves; said front mounted blade carrying at least one absolute height sensor in the closed loop; said aggregate carrying one inertial sensor in the closed loop; outputs of said absolute height sensor and single inertial sensor being combined in a calculating unit, the outputs being devoid of body angle or body rotation of the body of the earth moving equipment; output of said calculating unit and a set height being compared in a comparator, the comparator being in the controlled loop; output of said comparator providing the input for a regulator for controlling said valves; and wherein said one inertial sensor has a single degree of freedom, the output of which is angular velocity in a plane perpendicular to the connecting line between said pivot points, which for use in said calculating unit is converted to angular increment of said supporting arms in said plane.