Bosch’s new SMI540 is the first micromechanical inertial measurement unit for vehicle dynamics control in a low-cost SOIC 16w housing.
The unit opens up new development possibilities for vehicle Electronic Stability Programmes (ESP). The 3-D sensor simultaneously monitors three of a vehicle’s movement axes—two acceleration or inclination axes and one axis of rotation. Until now, at least two separate sensors were required for this. The SMI540 has a digital serial peripheral interface with two standard protocols. Thanks to a constant internal self-test of the yaw-rate sensor element, this interface meets the highest operating safety standards.
Two of SMI540’s three sensor signals provide information for the ESP system: the yaw rate and lateral acceleration. The third sensor signal measures acceleration and inclination in the vehicle’s direction of travel. Developers can use this information for other applications such as hill-hold, or fuel-saving functions in cars with automatic transmissions: The stopped car automatically shifts into Neutral if—and this is where the inclination sensor comes in—the car is on level ground and cannot begin to move by itself.
Samples of the new sensor are already available, and it is set for series production from the second quarter of 2010. Bosch also plan to launch the SMG540, a lower-cost version containing only the yaw sensor element.
