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A single-crystal silicon capacitive acceleration sensor for low-g applications has been developed. The sensor element itself is formed entirely from single crystal silicon, giving it exceptional stability over time and temperature and excellent shock resistance. The sensor is produced using low-cost, high volume processing, test and calibration. The sensor integrated circuit (IC) contains a proofmass which moves in response to applied accelerations. The position of the proofmass is capacitively detected and processed by an interface IC. The sensor/interface IC system is packaged in a small outline IC (SOIC) package for printed circuit board mounting. The module is designed to measure full scale accelerations in the 0.75g to 3g range to suit a variety of automotive, industrial and consumer applications

An algorithm for estimation of vehicle yaw rate and side slip angle using steering wheel angle, wheel speed, and lateral acceleration sensors is proposed. It is intended for application in vehicle stability enhancement systems, which use controlled brakes or steering. The algorithm first generates two initial estimates of yaw rate from wheel speeds and from lateral acceleration. A new estimate is subsequently calculated as a weighted average of the two initial ones, with the weights proportional to confidence levels in each estimate. This preliminary estimate is fed into a closed loop nonlinear observer, which generates the final estimate of yaw rate along with estimates of lateral velocity and side slip angle. Parameters of the observer depend on the estimated surface coefficient of adhesion, thus providing adaptation to changes in road surface coefficient of adhesion.

Automotive multi-sensor modules, capable of vehicle-wide communications via a data bus will be discussed. Proper sensor grouping, packaging and device placement are key issues in the implementation of smart sensor modules. Sensors that are candidates for clustering include temperature, acceleration, angular rate, barometric pressure, chemical, and light sensors. The capability to accommodate a variety of data bus communication protocols is required to satisfy the majority of automotive systems. System integration must be considered when employing a smart sensor network through-out an automobile in a cost effective manner. This paper will cover the module issues associated with sensing, packaging, electronics, communication and system integration.

A method of canceling unknown angular rate effects in impact immunity measurement for angular rate sensors is presented. A pair of the same type of testing sensors is arranged such that the sensing axes of the sensor pair are 180° out of phase. While an angular rate produces anti-phase component in the sensor outputs, a linear acceleration produces in-phase response from the sensors due to similar mechanical symmetry. This phase difference is used to cancel the angular rate component even though the actual angular rate may still be unknown. This cancellation can be derived from the sensor output transfer function and is supported with our experimental data.

In this paper a simple yet insightful model to predict vehicle propensity to rollover is proposed, which includes the effects of suspension and tire compliance. The model uses only a few parameters, usually known at the design stage. The lateral accelerations at the rollover threshold predicted by the model are compared to the results of simulations, in which vehicles with the same static stability factor, but different suspension characteristics and payloads are subjected to roll-inducing handling maneuvers. The results of simulations correlate well with the predictions based on the proposed model. Design recommendations for passive suspensions, which would increase rollover stability are discussed.