Shengbo Li

MPC based vehicular following control considering both fuel economy and tracking capability

To comprehensively deal with tracking capability and fuel economy issue of ACC-activated vehicle, this paper presents a MPC based vehicular following control algorithm. After compensating the nonlinearity of vehicle longitudinal dynamics by inverse model, the car-following system is built as 3-state space linear model. On its basis, a standard MPC optimization cost is constructed mainly considering the contradiction between fuel economy and tracking capability while other issues such as longitudinal ride comfort and driver acceptable tracking error are formulated as its I/O constraints. In order to avoid the computing infeasibility in receding horizon control, a slack variable is introduced to soften the I/O constraints, called ldquoSoftening Constraintrdquo. The success of MPC based vehicular following control algorithm is demonstrated under several traffic scenarios, showing its application improves both fuel economy and tracking capability while explicitly satisfying driver comfort requirement.

Study on robustness and feasibility of MPC based vehicular Adaptive Cruise Control system

Model Predictive Control (MPC) framework is becoming more and more attractive in designing vehicular Adaptive Cruise Control (ACC) system. However, benefiting from its advantage, e.g. close-loop optimality, MPC algorithm must overcome some of its practical problems, among which low robustness to model mismatch and computing infeasibility of control law are most critical. Aiming at MPC based vehicular ACC algorithm, this paper studies its robustness and computing feasibility issues for the purpose of applying the algorithm into vehicle products. In order to enhance its robustness to model mismatch, feedback correction method is adopted to compensate the predictive error of vehicular following model and improve its predictive precision on the system state. Constraint management method is employed to revise the cost function and soften the I/O constraints of predictive optimization problem, avoiding the computing infeasibility of control law caused by larger tracking errors. Series of simulations with a commercial truck model indicate that the adopted methods can effectively solve the low robustness and computing infeasibility problems of vehicular MO-ACC algorithm, laying a foundation for its implementation on vehicle products.

A driving simulation platform applied to develop Driver Assistance Systems

This paper presents a driving simulation platform for the development of Driver Assistance Systems (DAS) with the main purpose of promoting the testing of DAS hardware and advancing the verification of DAS performance. The platform uses a combination of two simulation loops, Hardware-In-the-Loop (HIL) and Driver-In-the-Loop (DIL). Its hardware consists of a simulation computer, a monitor computer, a vision computer, DAS actuators as well as a dummy car. Its software components include several specific ones. When designing its monitor software, a GUI-Driven-by-S-Function (GUIDSF) method is proposed to eliminate the delay in the displaying of the simulation data. The vision rendering software uses adjustment based on the principle of optical projection, considerably improving the drivers perception of being immersed in the virtual traffic scene. The success of the developed platform is demonstrated by HIL experiments of actuators and DIL experiments of ACC. They demonstrate that the proposed actuator control algorithm possesses good tracking capability and ACC is capable of improving ride comfort and reducing driver workload, and consequently, the platform is capable of speeding up DAS development.

Double-Mode vehicular Electronic Throttle for driver assistance systems

Normally used electronic assistant throttle actuators for R&D of vehicle longitudinal driver assistance systems, such as ACC, may conflict with cars primary throttle system and have inconvenience in switch between ACC control and driver operating. In order to overcome the disadvantages abovementioned, this paper addresses the design, control and experiments of a Double-Mode Electronic Throttle (DMET) which can be operated by ACC and driver synchronously. First, based on the existing electronic throttle system the structure of the DMET is designed. Then, focusing on the time delay of the DMET, a gain-adaptive Smith predictor based on a identified transfer function is set to get better system dynamic performance. Furthermore, in order to achieve seamless switch between ACC control mode and driver operating mode, a dead zone restriction is introduced to the controller. Finally, the system performance in tracking ACC desired throttle angle and switching between two operating modes is confirmed by series of experiments.

Pneumatic electronic braking assistance system using high-speed valves

In order to satisfy the request of the driving assistance systems (DAS) for heavy duty vehicles, a high-speed valves based pneumatic electronic braking assistance system (PEBAS) is developed. A novel configuration of PEBAS is designed and its mathematical model is built by analyzing the operation of the air-flow inside the high-speed valve. Based on the model, a PWM (pulse width modulation) method is used to control the high-speed valves and its duty cycle is adjusted by a PI controller in order to track the desired braking pressure. The controller is optimized according to test results of the high-speed valves. Then, an HIL (Hardware in-the-Loop) platform is built to validate the performance of the system. Experiments show that the control error of the developed PEBAS is less than 5%.