Research on accurate modeling and control for pneumatic electric braking system of commercial vehicle based on multi-dynamic parameters measurement

Abstract

Accurate pressure control and fast dynamic response are vital to the pneumatic electric braking system (PEBS) for those commercial vehicles that require higher regulation precision of braking force on four wheels when braking force distribution is carried out under some conditions. Due to the lagging information acquisition, most feedback-based control algorithms are difficult to further improve the dynamic response of PEBS. Meanwhile, feedforward-based control algorithms like predictive control perform well in improving dynamic performance but because of the large amount of computation and complexity of this kind of control algorithm, it cannot be applied in real-time on the single-chip microcomputer, and it is still in the stage of theoretical research at present. To address this issue and for the sake of engineering reliability, this article presents a logic threshold control scheme combining analogous model predictive control (AMPC) and proportional control. In addition, an experimental device for real-time measuring PEBS multi-dynamic parameters is built. After correcting the key parameters, the precise model is determined and the influence of switching solenoid valve on its dynamic response characteristics is studied. For the control scheme, numerical and physical validation is executed to demonstrate the feasibility of the strategy and for the performance of the controller design. The experimental results show that the dynamic model of PEBS can accurately reflect its pressure characteristics. Furthermore, under different air source pressures, the designed controller can stably control the pressure output of PEBS and ensure that the error is within 0.08 bar. Compared with the traditional control algorithm, the rapidity is improved by 32.5%.

A new compressible flow model for pneumatic directional control valves

“…The _ m p signal from the ''New flow model'' block is sent to the ''Pressure dynamics'' block, and the theoretical pressure change rate ( _ P t ) is derived with the help of equation (9). Then, the integral of the pressure change rate signal is taken to obtain absolute theoretical pressure value ([P a ] t ).…”

“…In these systems, the control of pressure, position, or velocity parameters is usually performed by controlling the mass flow of the air via a control valve. [6][7][8][9] Thus, the system of interest must be known to some extent, especially for the model-based control strategies, wherein the correct implementation of system model is crucial to meet the desired control performance. It is to be noted that the nonlinear relationship between the mass flow rate of air and the pressure dynamics makes the modeling issue a tedious task.…”

A Modeling and Control Algorithm for a Commercial Vehicle Electronic Brake System Based on Vertical Load Estimation

“…The controller is based on a simplified expression of system dynamics and considers the pressure variation caused by the switching state of the solenoid valve at the current and the last sampling time. Yang et al [2] proposed a logic threshold control scheme based on an EBS that combines analog model predictive control and proportional control. Hamada et al [3] conducted a comprehensive discussion on the basic principles of regenerative braking systems.…”