Claudio Vecchio

Vehicle Yaw Control via Second-Order Sliding-Mode Technique

The problem of vehicle yaw control is addressed in this paper using an active differential and yaw rate feedback. A reference generator, designed to improve vehicle handling, provides the desired yaw rate value to be achieved by the closed loop controller. The latter is designed using the second-order sliding mode (SOSM) methodology to guarantee robust stability in front of disturbances and model uncertainties, which are typical of the automotive context. A feedforward control contribution is also employed to enhance the transient system response. The control derivative is constructed as a discontinuous signal, attaining an SOSM on a suitably selected sliding manifold. Thus, the actual control input results in being continuous, as it is needed in the considered context. Simulations performed using a realistic nonlinear model of the considered vehicle show the effectiveness of the proposed approach.

Wheel Slip Control via Second-Order Sliding-Mode Generation

During skid braking and spin acceleration, the driving force exerted by the tires is reduced considerably, and the vehicle cannot speed up or brake as desired. It may become very difficult to control the vehicle under these conditions. To solve this problem, a second-order sliding-mode traction controller is presented in this paper. The controller design is coupled with the design of a suitable sliding-mode observer to estimate the tire-road adhesion coefficient. The traction control is achieved by maintaining the wheel slip at a desired value. In particular, by controlling the wheel slip at the optimal value, the proposed traction control enables antiskid braking and antispin acceleration, thus improving safety in difficult weather conditions, as well as stability during high-performance driving. The choice of second-order sliding-mode control methodology is motivated by its robustness feature with respect to parameter uncertainties and disturbances, which are typical of the automotive context. Moreover, the proposed second-order sliding-mode controller, in contrast to conventional sliding-mode controllers, generates continuous control actions, thus being particularly suitable for application to automotive systems.

Traction Control for Ride-by-Wire Sport Motorcycles: A Second-Order Sliding Mode Approach

This paper addresses the analysis and design of a safety-oriented traction control system for ride-by-wire sport motorcycles based on the second-order sliding mode methodology. The controller design is based on a nonlinear dynamical model of the rear wheel slip, and the modeling phase is validated against experimental data measured on an instrumented vehicle. To comply with practical applicability constraints, the position of the electronic throttle body is used as control variable and the effect of the actuator dynamics is thoroughly analyzed. After a discussion on the interplay between the controller parameters and the tracking performance, the final design effectiveness is assessed via mechanical simulation corporation BikeSim, a full-fledged commercial multibody motorcycle model.

Comparing Internal Model Control and Sliding-Mode Approaches for Vehicle Yaw Control

In this paper, the problem of vehicle yaw control using a rear active differential is investigated. The proposed control structure employs a reference generator designed to improve vehicle handling, a feedforward contribution that enhances the transient system response, and a feedback controller. Due to system uncertainties and the wide range of operating situations, which are typical of the automotive context, a robust control technique is needed to guarantee system stability. Two different robust feedback controllers, which are based on internal model control and sliding mode methodologies, respectively, are designed, and their performances are compared by means of extensive simulation tests performed using a realistic 14-degree-of-freedom (DOF) model of the considered vehicle. The obtained results show the effectiveness of the proposed control structure with both feedback controllers and highlight their respective benefits and drawbacks. The presented comparative study is a first step to devise a new mixed control strategy that is able to exploit the benefits of both the considered techniques.

Wheel slip control via second order sliding modes generation

During skid-braking and spin-acceleration, the driving force exerted by the tires reduces considerably and the vehicle cannot speed up or brake as desired. It may become very difficult to control the vehicle under these conditions. To solve this problem, a second order sliding mode traction controller for road vehicles is presented in this paper. The traction control is achieved by maintaining the wheels slip at the optimal value. In this way, the traction control enables anti-skid braking and anti^spin acceleration, thus improving safety in difficult weather conditions, as well as stability during high performance driving. The choice of the control methodology adopted in this paper is motivated by its robustness feature with respect to parameter uncertainties and disturbances which are typical of the automotive context. Moreover, the proposed second order sliding mode controller, in contrast to conventional sliding mode controllers, generates continuous control actions, thus resulting particularly suitable to be applied to automotive systems, where vibrations limitation is a crucial requirement.

Sliding mode control for urban vehicles platooning

In the short term future, cybernetic transport systems (CTS), based on fully automated urban vehicles (the so-called Cybercars), will be seen on city roads and on new dedicated infrastructures. The objective of the Cybercars is to achieve a more effective organization of urban transport, resulting in a more rational use of motorized traffic, with less congestion and pollution and safer driving. One necessary functionality of Cybercars is the ability to cooperate and run in a platoon at close range. Platooning of these automatic guided cars is addressed in this paper, and decentralized control schemes for autonomous vehicle are proposed. Due to system uncertainties and the wide range of operating conditions, which are typical of the automotive context, a robust control technique is required to solve the problem. The robust control methodologies adopted in this paper are first order and second order sliding mode control, which result particularly suitable to deal with uncertain nonlinear time-varying systems. The proposed control schemes are compared through simulations.

Low Vibration Vehicle Traction Control to Solve Fastest Acceleration/Deceleration Problems Via Second Order Sliding Modes

A traction force controller for passenger cars is presented in this paper to solve, in particular, the problem of guaranteeing the satisfaction of the fastest stable acceleration/deceleration conditions during vehicle operations. This problem is, for instance, an important subtask in the design of Intelligent vehicles/highways systems (IVHS), but it can be considered crucial also for any kind of modern medium to high-performance commercial cars. Due to system uncertainties, time-varying road conditions, and the wide range of operating conditions, which are typical of the automotive context, a robust control technique is required to solve this problem. The robust control methodology adopted in this paper is the so-called second order sliding mode control, which results particularly suitable to deal with uncertain nonlinear time-varying systems. Moreover, in contrast to conventional sliding mode control, second order sliding mode control generates continuous control actions, the discontinuities being confined to the derivatives of the control signals, thus resulting particularly suitable to be applied to automotive systems where vibrations suppression is a crucial requirement.

Switched second order sliding mode for wheel slip control of road vehicles

Longitudinal wheel slip control is a crucial problem in automotive systems, as it it is the basis for traction, braking and stability control. As slip dynamics are critically dependent on the vehicle speed, it is interesting to devise an adaptation of the controller parameters with respect to this variable. To achieve this, the present paper proposes a novel switched second order sliding mode (S-SOSM) control strategy, which allows to enhance the closed-loop performance and tune it to the current working condition.

Slip Control for Vehicles Platooning via Second Order Sliding Modes

Recent research has demonstrated that longitudinal control strategies are useful in highway systems to regulate the spacing and velocity of vehicles. In this paper, a robust longitudinal control system for platoons of vehicles is designed. The proposed control scheme is composed of two different loops: the outer loop has to determine the traction force necessary to maintain the safety distance between the controlled vehicle and the preceding vehicle, while the inner loop is aimed at producing the desired traction force, calculated by the outer loop, by controlling the slip ratio. The unknown time-varying road conditions are taken into account by using an adaptive algorithm. The proposed controller enforces second order sliding modes, and, in contrast to conventional sliding mode controllers generates continuous control actions, thus resulting particularly suitable to be applied to automotive systems, where vibrations limitation is a crucial requirement.

Cruise control with collision avoidance for cars via sliding modes

Longitudinal control of platoons of vehicles is appropriate to improve the traffic capacity of road networks while maintaining safety distances between vehicles. This paper investigate the possibility of reducing the number of accidents involving pedestrians or other vulnerable road users, like cyclists and motorcyclists, by providing the control systems of the vehicles of the platoon with some collision detection and avoidance capability. The driver assistance system is realized by means of vehicle supervisors, which, on the basis of the data acquired by the sensors, make the decision on which is the appropriate current control mode for each controlled vehicle, and manage the switches among low-level controllers