Vehicle adaptive cruise control strategy based on improved safe distance model for off-roads with changeable pavement and slope

Compared with the structured environment, off-road environment has complex and ever-changing road conditions. This paper is focused on the vehicle adaptive cruise task for vehicles driving on complex off-road terrain. Traditional ACC strategies do not take the complex road conditions into consideration, thus easily make the relative distance between vehicles unreasonable. To solve this problem, an off-road adaptive cruise control (OACC) strategy is proposed for off-roads with changeable pavement and slope. Firstly, the influence of road conditions and vehicle relative motion states on safe distance between vehicles have analyzed with the aim of developing a more reasonable space strategy for off-road conditions. Then, based on the analysis results, an improved safe distance model (ISDM) is proposed which take the influence factors into account comprehensively. The concept of road impact factor is proposed to prevent model degradation and effectively balance the influence of single road conditions and comprehensive factors on safe distance. Besides, target to improve the adaptability of ACC, a novel state space model has developed which can handle not only the change of vehicle motion states but also road conditions. In addition, the MPC-based OACC for off-road environment is proposed, which can enable the vehicle to better adapt to relative motion states and road conditions based on the novel state space model. Finally, the performance of OACC is verified by co-simulation in MATLAB/Simulink and Carsim, and a hardware-in-the-loop simulation system. Furthermore, the analysis of ISDM has conducted to illustrate the differences and similarities compared with the traditional safe distance models and to verify the effectiveness of ISDM. Simulation results show that the OACC and ISDM proposed in this paper have great performance in different off-road working conditions.