Stability Control Sensors: Notes

The RCM  inertial signals consist of the yaw rate sensor, roll rate sensor, lateral accelerometer and longitudinal accelerometer. The RCM  is usually mounted as close as possible to the center point of the vehicle to get the most accurate readings. Information from the RCM  sensors is sent to the ABS module over a dedicated Controller Area Network (CAN) bus.

• The yaw rate sensor measures the relative vehicle motion about the vertical axis through its center of gravity.
• The roll rate sensor measures the rate of rotation along the front to rear horizontal axis.
• The lateral accelerometer measures the acceleration that corresponds to the force involved when the vehicle moves sideways.
• The longitudinal accelerometer measures the acceleration corresponding to the force involved when the vehicle moves forward and rearward in the horizontal plane, along the centerline of the front and rear wheels.

Lateral acceleration has 2 forms. The first is the centrifugal acceleration that is generated when the vehicle travels around in a circle. The second is the acceleration due to gravity. On level ground there is no contribution from this acceleration. However, if the vehicle is parked sideways on a bank or incline, the sensor measures some lateral acceleration due to gravity, even though the vehicle is not moving.