Automatic Blade Slope Control System

An apparatus for controlling a blade mounted on a vehicle, the apparatus comprising:

• means for receiving at a first time a first angular velocity measurement about a first axis, a second angular velocity measurement about a second axis, and a third angular velocity measurement about a third axis from a three-axis gyroscope mounted on the blade, wherein the first axis, the second axis, and the third axis are orthogonal;
• means for receiving at a second time a blade slope angle measurement from a blade slope angle tilt sensor mounted on the blade;
• means for receiving at a third time a blade tip angle measurement from a blade tip angle tilt sensor mounted on the blade;
• means for determining whether the second time is greater than the first time;
• means for, upon determining that the second time is greater than the first time:
• determining whether the received blade slope angle measurement is valid;
• means for determining whether the third time is greater than the first time;
• means for, upon determining that the third time is greater than the first time:
• determining whether the received blade tip angle measurement is valid;
• and
• means for, upon determining that the second time is greater than the first time, the received blade slope angle measurement is valid, the third time is greater than the first time, and the received blade tip angle measurement is valid:
• computing an estimate of the blade slope angle based on the received first angular velocity measurement, the received second angular velocity measurement, the received third angular velocity measurement, the received blade slope angle measurement, and the received blade tip angle measurement.

A computer readable medium for storing computer program instructions for controlling a blade mounted on a vehicle, the computer program instructions defining the steps of:

• receiving at a first time a first angular velocity measurement about a first axis, a second angular velocity measurement about a second axis, and a third angular velocity measurement about a third axis from a three-axis gyroscope mounted on the blade, wherein the first axis, the second axis, and the third axis are orthogonal;
• receiving at a second time a blade slope angle measurement from a blade slope angle tilt sensor mounted on the blade;
• receiving at a third time a blade tip angle measurement from a blade tip angle tilt sensor mounted on the blade;
• determining whether the second time is greater than the first time;
• upon determining that the second time is greater than the first time:
• determining whether the received blade slope angle measurement is valid;
• determining whether the third time is greater than the first time;
• upon determining that the third time is greater than the first time:
• determining whether the received blade tip angle measurement is valid;
• and
• upon determining that the second time is greater than the first time, the received blade slope angle measurement is valid, the third time is greater than the first time, and the received blade tip angle measurement is valid:
• computing an estimate of the blade slope angle based on the received first angular velocity measurement, the received second angular velocity measurement, the received third angular velocity measurement, the received blade slope angle measurement, and the received blade tip angle measurement.