**1. Introduction**

The proposed system can be found in windshield wiper on the front window of the car in which the rotary motion of the cam transforms into an oscillating motion. Yang et al. introduced the mathematical model to describe the separation, transient impact, and contact in cam follower system using oblique impact, [1]. They showed that the cam and the follower system kept permanent contact without the use of coefficient of restitution at low speeds for the cam. Yousuf studied the detachment between the cam and the follower using largest Lyapunov exponent parameter, power density function of Fast Fourier Transform (FFT), and Poincare' maps due to the nonlinear dynamics phenomenon of the follower. Nonlinear response of the follower displacement is calculated at different cam speeds, different coefficient of restitution, different contact conditions, and different internal distance of the follower guide from inside [2, 3]. Flores et al. used a nonsmooth dynamics approach to model the interaction of the colliding bodies using Coulomb's law for dry friction [4]. Lassaad et al. studied the effect of cam profile error on the nonlinear dynamics behavior of oscillating roller

follower system by using a model with eight degrees of freedom of two nonlinear Hertzian contacts [5]. Li and Du used the coefficient of restitution as a main control parameter to analyze the periodic movement and the bifurcation region in Non-fixed constrained collision vibration system [6]. Wu et al. studied the influence of the joint clearance on the dynamic response of a planar mechanism with two driving links and prismatic pair clearance under variable input speeds [7]. They concluded that the largest Lyapunov exponents are dependent on the clearance size and the input speed. Chen et al. identified the chaos phenomenon of the 2-DOF nine-bar mechanism with a revolute clearance using the phase diagrams, the Poincaré portraits, and largest Lyapunov exponent parameter [8]. Bifurcation diagrams with changing clearance value, friction coefficient, and driving speed are drawn. The aim of this paper is to discuss the chaotic phenomenon of an offset follower through the use of impact coefficient of restitution at different follower guides' clearances and different cam speeds.
