BMW's dynamic drive: an active stabilizer bar system

BMW has developed an active stabilizer bar system, called Dynamic Drive, which significantly reduces roll angle during cornering. For higher lateral accelerations, the roll angle increases gradually at the same rate as in conventional cars to alert the driver to the proximity of the stability limit. In addition, the self-steering properties of the vehicle, including understeering and oversteering, improve handling, agility, steering precision, and safety. The Dynamic Drive system consists of a hydraulic valve block with integrated sensors, a hydraulic pump coupled to the power steering pump, a lateral acceleration sensor, a control unit, several hydraulic lines, and two active stabilizer bars with rotating hydraulic actuators. The main control inputs for the Dynamic Drive system are steering angle and lateral acceleration. A dynamic observer implemented in the electronic control unit calculates the necessary vehicle stabilization torque based on a prediction derived from the steering angle signal and lateral acceleration.