## 6 Discussion  
In the software cosimulation, different vehicle speeds and different road adhesion coefficients were tested. As the vehicle speed increases, the ESC control algorithm based on the tire force sensor shows better stability. The PID-controlled ESC control algorithm will have a significant overshoot and the nominal yaw rate value will not follow tightly as the vehicle speed increases. The difference between the different ESC control algorithms on the road with low adhesion coefficient is more obvious. Generally speaking, the ESC controller based on tire force control follows the situation of the nominal yaw rate better than the traditional PID controller (without the tire force sensor), the difference between the two is not obvious on the road with high adhesion coefficient.  
In the hardware-in-the-loop test, in addition to obtaining the same conclusions as in the software cosimulation, it can also be concluded from the wheel cylinder pressure diagram in the sine with dwell condition that the conventional PID controller sends signals to the actuator more frequently than the ESC controller based on the tire force sensor, which indicates that the ESC control algorithm based on the tire force sensor can effectively improve the efficiency of ESC control of the vehicle, improve the control accuracy, and reduce the number of false triggers. However, this conclusion still needs to be further tested and verified.  
Compared with the traditional PID-controlled controller, the ESC controller based on tire force observation in this paper shows some advantages in the case of a low road adhesion coefficient and improves the following situation of the nominal value of yaw rate. This proves that the use of the tire force collected by the tire force sensor as the input of the ESC controller can compensate for the inaccurate expression of the tire model under extreme operating conditions and nonlinear conditions, thus proving that the use of a controller based on tire force observation can be a new idea to improve the control accuracy of the chassis electronic control system.  
There are still some limitations to this paper. Firstly, under extreme conditions, there is a large difference in the follow-through of the actual value to the nominal value of the side slip angle, but the vehicle is still in a stable state that does not require ESC access control. Therefore, this article does not carry out the test results of the side slip angle analysis. Secondly, another question is mostly focused on the actuator response in the hardware-in-the-loop test. The actuator response accuracy and rate will have a large impact on the control effect of the ESC controller; therefore, future work will focus on the controller algorithm to consider the inherent problems of the actuator and improve the speed of solenoid valve boosting in ESC.  
Conceptualization, D.L. and Y.M.; methodology, Y.M.; software, H.Y.; validation, D.L., Y.M. and H.Y.; formal analysis, Y.M.; investigation, Z.D.; resources, J.Q.; data curation, H.Y.; writing--original draft preparation, H.Y.; writing--review and editing, Y.M.; visualization, Z.D.; supervision, D.L.; project administration, D.L.; funding acquisition, J.Q. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Government of Liuzhou and SAIC-GM-Wuling Automobile, grant number 2018 AA20501.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.