Dynamic percent grade measurement device

A combination of components for the dynamic measurement of the grade of terrain comprising:

• a rocker arm disposed across a wheel of a vehicle, the rocker arm having a first end and a second end, the rocker arm allowed to pivot about a pivot point substantially midway between the first end and the second end;
• a rotational damper positioned adjacent the pivot point to maintain the rocker arm at a substantially level relationship with respect to gravity;
• a first displacement transducer positioned at said first end of the rocker arm and a second displacement transducer positioned at said second end of the rocker arm, said first and second displacement transducers equidistant from a vertical centerline of said rocker arm;
• a tilt sensor positioned on the rocker arm to provide the angle of the rocker arm relative to earth horizontal;
• and
• a processing unit to process measurement data signals from said first and second displacement transducers and said tilt sensor and calculates a percent grade measurement using the following formula:
• % Grade=(((B−A)/C)−D)×100
• where A is equal to the distance to the terrain from the first displacement transducer, B is equal to the distance to the terrain from the second displacement transducer, C is equal to the distance between the first and second displacement transducers, and D is equal to the rise over run of the angle of the rocker arm relative to earth horizontal as measured by the tilt sensor.

A method for the dynamic measurement of the grade of terrain comprising:

• providing a rocker arm disposed across a reference structure, the rocker arm having a first end and a second end, the rocker arm allowed to swing to maintain a substantially level relationship with respect to gravity;
• measuring a first displacement using a first displacement transducer positioned at said first end of the rocker arm;
• measuring a second displacement using a second displacement transducer positioned at said second end of the rocker arm, said first and second displacement transducers equidistant from a vertical centerline of said rocker arm;
• measuring the rise over run of the angle of the rocker arm relative to earth horizontal;
• and
• calculating a percent grade measurement using the first displacement, second displacement and rise over run of the angle of the rocker arm relative to earth horizontal measurements.