Tyre-Road Adherence Conditions Estimation for Intelligent Vehicle Safety Applications

2018

Abstract:In this paper, we analyze the behavior of a single pad system in the presence of dry friction. The goal is to investigate the path that leads a stable mechanical system to unstable behavior. In doing so, we studied the behavior of a discrete three DOF model, a continuous model and a finite element model of the pad. The numerical results are consistent with the experimental investigation conducted on a brake disk for railway application.

Section: Discussionmentioning

confidence: 99%

Modal Coupling in Presence of Dry Friction

Simone

2018

“…In particular, wheeled mobile robots, which represent the mobile robots of interest for this investigation, must be modeled as nonholonomic mechanical systems to capture the pure rolling conditions of the wheels. Thus, the nonlinear control problem of this family of mechanical systems represents a challenging engineering issue [64][65][66][67]. In the literature, the nonlinear control methods employed for this class of mechanical systems are based on non-standard approaches that cannot be easily extended to both holonomic and nonholonomic mechanical systems [68][69][70].…”

Section: Literature Reviewmentioning

confidence: 99%

Forward and Inverse Dynamics of a Unicycle-Like Mobile Robot

Pappalardo

2019

In this research work, a new method for solving forward and inverse dynamic problems of mechanical systems having an underactuated structure and subjected to holonomic and/or nonholonomic constraints is developed. The method devised in this paper is based on the combination of the Udwadia-Kalaba Equations with the Underactuation Equivalence Principle. First, an analytical method based on the Udwadia-Kalaba Equations is employed in the paper for handling dynamic and control problems of nonlinear nonholonomic mechanical systems in the same computational framework. Subsequently, the Underactuation Equivalence Principle is used for extending the capabilities of the Udwadia-Kalaba Equations from fully actuated mechanical systems to underactuated mechanical systems. The Underactuation Equivalence Principle represents an efficient method recently developed in the field of classical mechanics. The Underactuation Equivalence Principle is used in this paper for mathematically formalizing the underactuation property of a mechanical system considering a particular set of nonholonomic algebraic constraints defined at the acceleration level. On the other hand, in this study, the Udwadia-Kalaba Equations are analytically reformulated in a mathematical form suitable for treating inverse dynamic problems. By doing so, the Udwadia-Kalaba Equations are employed in conjunction with the Underactuation Equivalence Principle for developing a nonlinear control method based on an inverse dynamic approach. As shown in detail in this investigation, the proposed method can be used for analytically solving in an explicit manner the forward and inverse dynamic problems of several nonholonomic mechanical systems. In particular, the tracking control of the unicycle-like mobile robot is considered in this investigation as a benchmark example. Numerical experiments on the dynamic model of the unicycle-like mobile robot confirm the effectiveness of the nonlinear dynamic and control approaches developed in this work.

“…In order to solve this important problem, different analytical approaches, computational methods, and experimental solutions have been extensively developed and tested in recent years. For instance, the methods based on the State-Dependent Riccati Equation (SDRE), the feedback linearization method, the sliding mode control approach, and nonlinear control methods based on the control-Lyapunov function represent effective control strategies suitable for solving the vibration control problem associated with a nonlinear mechanical system [18][19][20][21][22][23][24][25][26][27][28][29]. Moreover, the vibration control problem is particularly challenging in the case of rigid-flexible multibody mechanical systems.…”

Section: Literature Reviewmentioning

confidence: 99%

Use of the Adjoint Method for Controlling the Mechanical Vibrations of Nonlinear Systems

Pappalardo

2018

In this work, the analytical derivation and the computer implementation of the adjoint method are described. The adjoint method can be effectively used for solving the optimal control problem associated with a large class of nonlinear mechanical systems. As discussed in this investigation, the adjoint method represents a broad computational framework, rather than a single numerical algorithm, in which the control problem for nonlinear dynamical systems can be effectively formulated and implemented employing a set of advanced analytical methods as well as an array of well-established numerical procedures. A detailed theoretical derivation and a comprehensive description of the numerical algorithm suitable for the computer implementation of the methodology used for performing the adjoint analysis are provided in the paper. For this purpose, two important cases are analyzed in this work, namely the design of a feedforward control scheme and the development of a feedback control architecture. In this investigation, the control problem relative to the mechanical vibrations of a nonlinear oscillator characterized by a generalized Van der Pol damping model is considered in order to illustrate the effectiveness of the computational algorithm based on the adjoint method by means of numerical experiments.