# Vehicle Rollover Warning and Control Based on Attitude Detection and Fuzzy PID
## 1 Introduction
The anti-rollover system starts to work by calculating the lateral position of the vehicle's zero moment point, deriving the theoretical time when the vehicle rollover occurs, and comparing whether the vehicle's secondary predicted zero moment point lateral position is greater than the set threshold value. The anti-rollover control strategy of differential braking based on the fuzzy PID algorithm was selected to brake the front outer wheels of the vehicle. [PERSON] et al. [13] proposed a time-to-rollover warning algorithm for TTR, which uses the lateral load transfer ratio as a rollover decision indicator. [PERSON] et al. [14] designed an ARM11-based rollover warning algorithm to detect the rollover attitude of a vehicle and alert the driver to take appropriate measures when the rollover reaches the trigger condition. [PERSON] [15] and other scholars used multi-sensor fusion to detect the operating state of the vehicle and used the real-time lateral load transfer rate (LTR) as the early warning algorithm for vehicle rollover. Since LTR has good universality and its results are not influenced by the vehicle model and operating environment, etc., in a comprehensive analysis, LTR was selected as the evaluation index of vehicle rollover in this study, and the braking scheme of the wheels was developed according to the actual value of LTR. The active anti-rollover technologies of vehicles primarily improve the rollover threshold of vehicles, mainly active suspension [16] and semi-active suspension [17], active anti-rollover stabilizer bars [18], active steering [19], differential braking [20], etc. The above active-control techniques can be performed without significantly changing the main structure of the vehicle. [PERSON] et al. [21] designed active variable-geometry suspension based on ground touring vehicles and combined it with corresponding controllers to verify whether it can reduce body acceleration, roll angle, etc. and improve the lateral stability of the vehicle. [PERSON] [22] and colleagues proposed an adaptive semi-active suspension system based on AdaBoost to enhance the anti-roll capability of the vehicle. [PERSON] [23] and other scholars designed an active sway bar stabilization system based on an electro-hydraulic actuator to achieve vehicle driving stability by adding an additional transverse sway moment and selecting quadratic optimal control as the algorithm of the system controller. [PERSON] [24] and others developed a nonlinear prediction-based active steering control strategy to minimize the vertical load variation of the wheels by controlling the actual transverse swing angular velocity, which can improve the stability of the vehicle. However, owing to the complex and expensive suspension structure, it is less often applied. The active anti-roll stabilizer bar, although simple in structure, is not easy to load in existing vehicle systems. Since the model studied in this paper was for forest fire trucks, active steering has certain constraints when the vehicle is driven on fire roads, and the situation considered is more complicated. At present, the anti-rollover control of heavy vehicles mostly adopts the differential braking method [25; 26; 27; 28], so after comprehensive consideration, we selected the control strategy of line-control action for the anti-rollover control of a forest fire truck during the driving process. Brake by wire is divided into electro-hydraulic brake-by-wire (EHB) and electro-mechanical brake-by-wire (EMB). Electro-hydraulic brakes combine electronically controlled technology with conventional hydraulic brakes, using a booster mechanism instead of a vacuum booster, with backup braking capability. Compared to EHB, electro-mechanical brakes no longer use hydraulic technology, and they respond directly to the braking demand with motor and mechanical components [29; 30; 31; 32; 33] to achieve faster response and higher operational accuracy.