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In order to reduce the risk of rollover accident in the process of liquid tank semi-trailer driving through a curved road section, a control method for the safe speed of liquid tank semi-trailer on curved road was proposed on the basis of optimal control theory. This control method prioritizes the prevention and control of rollover accidents before traffic efficiency, and achieves “preventive” active safety control by providing optimal speed control profiles for liquid tank semi-trailers driving towards curved road, without potential lateral instability hazards. The sine wave equation was used to fit the longitudinal transfer process of liquid in the tank to improve the effectiveness of the control profiles. Then a tank liquid sloshing model was built to describe the liquid motion on both vertical and horizontal dimensions. This model utilizes the lateral displacement law of liquid in the tank based on the improved quasi-static method, which can improve the accuracy of the lateral steady state characterization index of liquid tank semi-trailer in the cost function of the optimal control problem. The simulation results show as follows. The instantaneous lateral load transfer rates of the controlled liquid tank semi-trailers during driving through curved roads are within the safe range of [ - 0. 7,0. 7]. The decreasing of instantaneous lateral load transfer rate of vehicles could be observed under different curve radii, and the maximum decline occurs at curve radius of 61 meters. The maximum instantaneous lateral load transfer rate of the controlled vehicle has a maximum reduction of 0. 07. The control profiles have less negative impact on traffic efficiency. It is concluded that this optimization control method of safety vehicle speed helps liquid tank semi-trailers avoid rollover accidents, and is suitable for various curved road sections with different radii. [ABSTRACT FROM AUTHOR]

To ensure that a liquid tank semi-trailer has good yaw stability and path-following performance on low-adhesion roads under turning conditions, a multi-object PID differential braking-control method is proposed, which takes the tractor yaw rate, semi-trailer yaw rate, and articulation angle as the control parameters. According to the principle of equivalence, the trammel pendulum (TP) model is used to simulate the liquid sloshing effect in the liquid tank, and the Fluent software is used to identify the key parameters of the trammel pendulum model and verify the correctness of its simulation effect. Then, a co-simulation model is built based on TruckSim and MATLAB/Simulink. Based on the simplified six degrees of freedom model and the co-simulation model of a liquid tank semi-trailer, a multi-object PID differential braking-control method is designed, and the vehicle state responses with and without control are compared when it is turning on a low-adhesion road. The simulation results show that the proposed multi-object PID differential braking-control method can effectively improve the yaw stability and path-following performance of the liquid tank semi-trailer when turning on a low-adhesion road. [ABSTRACT FROM AUTHOR]

It is different for the liquid tank semi-trailer to keep roll stability during turning or emergency voidance, and that may cause serious accidents. Although the scholars did lots of research about the roll stability of liquid tank semi-trailer in theory by calculating and simulation, how to make an effective early warning of rollover is still unsolved in practice. The reasons include the complex driving condition and the difficulty of the vehicle parameter obtaining. The feasible method used currently is evaluating the roll stability of a liquid tank semi-trailer by the lateral acceleration or the attitude of the vehicle. Unfortunately, the lateral acceleration is more useful for sideslip rather than rollover, and the attitude is a kind of posterior way, which means it is hard to take measures to cope with the rollover accident when the attitude exceeds the safety threshold. Considering the movement of the vehicle is totally caused by the wheel force, the rollover could also be predicted by the changing of the wheel force. Therefore, in this paper, we developed a method to analyze the roll stability by the vertical wheel force. A thorough experiment environment is established, and the effectiveness of the proposed method is verified in real driving conditions. [ABSTRACT FROM AUTHOR]

To ensure that a liquid tank semi-trailer has good yaw stability and path-following performance on low-adhesion roads under turning conditions, a multi-object PID differential braking-control method is proposed, which takes the tractor yaw rate, semi-trailer yaw rate, and articulation angle as the control parameters. According to the principle of equivalence, the trammel pendulum (TP) model is used to simulate the liquid sloshing effect in the liquid tank, and the Fluent software is used to identify the key parameters of the trammel pendulum model and verify the correctness of its simulation effect. Then, a co-simulation model is built based on TruckSim and MATLAB/Simulink. Based on the simplified six degrees of freedom model and the co-simulation model of a liquid tank semi-trailer, a multi-object PID differential braking-control method is designed, and the vehicle state responses with and without control are compared when it is turning on a low-adhesion road. The simulation results show that the proposed multi-object PID differential braking-control method can effectively improve the yaw stability and path-following performance of the liquid tank semi-trailer when turning on a low-adhesion road.