Method for road grade/vehicle pitch estimation

A method of pitch alignment for sensors of an automotive vehicle, said method comprising:

• generating a yaw rate signal corresponding to vehicle yaw rate;
• generating a roll rate signal corresponding to vehicle roll rate;
• generating a lateral acceleration signal corresponding to vehicle lateral acceleration;
• determining when the vehicle is operating in a steady state turning condition;
• generating a pitch angle alignment θ when the vehicle is in the steady state turning condition where:
• θ≈ωx+tan θ·ωz
• where ωx and ωz, are said roll rate and yaw;
• and
• calibrating the yaw rate signal and the roll rate signal in response to the pitch angle alignment.

A control system for an automotive vehicle having a vehicle body comprising:

• a yaw rate sensor generating a yaw motion signal corresponding to a yaw motion of the vehicle body;
• a longitudinal accelerometer generating a longitudinal acceleration signal corresponding to a longitudinal acceleration of a center of gravity of the vehicle body;
• a lateral velocity sensor generating a lateral velocity signal corresponding to the lateral velocity of the vehicle body;
• and
• a controller coupled to said yaw rate sensor, said longitudinal accelerometer and said lateral velocity sensor, said controller determining a longitudinal speed from said longitudinal acceleration signal, said controller determining a vehicle pitch angle in response to said longitudinal speed, said yaw rate signal and said lateral velocity signal.