A Unified Framework of Adaptive Cruise Control for Speed Limit Follower and Curve Speed Control Function

Today many vehicles are being developed with advanced computing and sensing technologies. These new technologies have contributed in enhancing driving safety and convenience. As an example, the Adaptive Cruise Control (ACC) can automatically adjust the vehicle speed to driver's set speed and maintain the driver-requested headway distance to the lead vehicle. In this paper, we further consider the automatic control of speed according to the road attributes, e.g., the speed limit and curve of the road. Two new features, ‘speed limit follower’ and ‘curve speed control’ algorithms, are proposed in this paper. These new features communicate with the conventional ACC system and control the vehicle speed while traveling across different curved roads and speed limit zones. These new features were developed as an independent function, so they can be integrated with any other existing ACC systems. The key enabler for these features is sensing the speed limit and the curvature of upcoming roads using the OnStar GPS and a digital Map. The speed planning algorithm determines the desired vehicle speed profile to provide smooth speed transition along the road curve and the speed limit changes. The vehicle control system regulates the speed of the vehicle according to the desired speed profile. The speed limit follower and the curve speed control algorithms are implemented into a test vehicle with the production cruise control module. The vehicle test results are provided at the end of the paper.