# Vehicle Rollover Warning and Control Based on Attitude Detection and Fuzzy PID
## 5 Conclusions  
1. In this paper, an anti-rollover wire-controlled auxiliary braking system was designed for the rollover problem of forest fire trucks. The proposed three-degrees-of-freedom dynamics model of the forest fire truck was first built in MATLAB/Simulink, and the dynamics model was simulated and verified in CarSim under the steering wheel angle step input condition and double-shift line condition. The auxiliary braking control system consisted of a vehicle rollover warning module and a wire-controlled auxiliary braking system. The vehicle rollover warning module was intended to use the real-time roll angle and its angular velocity obtained by the inertial guidance system as input variables, and the lateral load transfer rate (LTR) as the rollover evaluation index and determine whether the current body attitude is in the rollover critical state according to the algorithm. The wire-controlled auxiliary braking system adopted the electro-hydraulic wire-controlled actuation system (EHB) to achieve vehicle speed reduction by differential braking technology in the rollover critical state. The braking system consisted of a DC reducer motor, plunger pump, accumulator, solenoid valve, hydraulic brake line, brake sub-pump caliper assembly, brake pressure sensor, electronic control unit and so on. When the wire-controlled auxiliary braking system worked, it first obtained the current body attitude parameters, calculated the required target brake wheel cylinder pressure through PID/Fuzzy-PID control, and then applied differential braking to the front left/right wheels of the vehicle to provide intervention transverse moment and reduce the rollover tendency of the vehicle. To verify the effectiveness of the designed braking system, two extreme operating conditions were selected to analyze the control effects of PID control and fuzzy-PID. For both, the maximum lateral acceleration improved by at least 42.8% and the maximum slide slip angle improved by 32%, while for the maximum roll, the fuzzy PID was able to advance the control to reduce the maximum roll by 20%, while the PID control was only able to control within 5%. The results showed that both PID and fuzzy-PID control algorithms can reliably calculate the target brake wheel cylinder pressure. The latter control effect is better than the former, PID control is at least 2 s delayed than fuzzy PID with faster response, shorter adjustment time and smaller overshoot;
2. In order to design a more perfect braking system in future work, and to verify the execution capability of the hardware of the EHB system, it is also necessary for it to perform hydraulic simulation to verify whether it can realize the process of rapid  
Figure 16: Response curve of J-turn condition: (**a**) LTR; (**b**) yaw rate; (**c**) lateral acceleration; (**d**) side slip angle; (**e**) roll; and (**f**) braking torque.  
increase and slow decompression, as well as to design the appropriate brakes and other related components according to the selected vehicle.  
Conceptualization, X.X. and S.C.; methodology, R.W. and N.G.; software, R.W.; validation, X.X., R.W. and Z.Y.; formal analysis, S.C. and N.G.; investigation, X.X.; resources, S.C.; data curation, X.X.; writing--original draft preparation, R.W.; writing--review and editing, S.C.; visualization, Z.Y.; supervision, X.X.; project administration, N.G.; funding acquisition, N.G. and Z.Y. All authors have read and agreed to the published version of the manuscript.  
This study was funded by the Key-Area Research and Development Program of Guangdong Province 2020B0303020001 and the Guangdong Basic and Applied Basic Research Foundation under Grant 2020B1515120056.  
Not applicable.  
The authors declare no conflict of interest.