Modern road vehicles are employing features of driver assistance systems (DAS) to improve drivability performance, comfort, and safety. In the future perspective, the advances in this field will lead ...these systems to the level of autonomous and cooperative driving, based on sensors networks and sensor fusion. This paper aims to present the readers a novel strategy for lane detection and tracking, which fits as a functional requirement to deploy DAS features like Lane Departure Warning and Lane Keeping Assist. To achieve the presented results, the digital image processing was divided into three levels. At the low-level, the input image dimensionality is reduced from three to one layer, the sharpness is improved, and region of interest is defined based on the minimum safe distance from the vehicle ahead. The feature extractor for lane edges detection design is part of the mid-level processing. The lane tracking strategy development is discussed in the high-level stage; Hough Transform and a shape-preserving spline interpolation are used to achieve a smooth lane fitting. The experimental outcomes were qualitatively and quantitatively evaluated using a ground truth comparison. The strategy shows good accuracy levels, including scenarios with shadows, curves, and road slope.
•Experimental and mathematical models of a pendulum driven by DC motors are developed.•Good agreement between numerical simulations and experimental data is obtained.•Bifurcation dynamics is ...investigated by experimental and numerical methods.•Passive control of chaos with magnetic rheological rotational damper is proposed.
In the present work, we deal with a dynamical analysis and passive control of chaos with magnetic rheological (MR) rotational damper in a pendulum driven by a DC motor via slider mechanism. A mathematical model for electromechanical system composed of a pendulum driven horizontally by through a DC motor and a slider-crank mechanism is presented and the parameters are estimated based on experimental data. Numerical and experimental results demonstrate that for certain values of the motor input voltage they can lead the system to chaotic behavior. For dynamic analysis, bifurcation diagrams, Poincaré sections, phase diagrams and 0–1 test are considered. In order to suppress the chaotic behavior, it is proposed to include MR rotational damper, as a passive control. In the case of the passive rotational MR damper, the influence of the introduction of the MR damper in a pendulum is performed considering the bifurcation diagrams. The numerical results show that the introduction of a passive rotational MR damper suppresses the chaotic behavior of the system. Additionally it is shown that it is possible to keep the pendulum oscillating with periodic behavior using the rotational MR damper with energizing discontinuity.
This paper presents the results of studies on reducing the amount of vibrations in different frequency ranges generated by a combustion engine through the use of different types of engine mounts. ...Three different types of engine supports are experimentally and numerically analyzed, namely an elastomeric engine mount, an elastomeric engine mount with a hydraulic component and standard decoupling, and an elastomeric engine mount with a hydraulic component and a modified decoupler-with this engineering design being a novelty in the literature. Experimental tests that considered different excitation frequencies were performed for the three types of engine mounts. Experimental data for stiffness and damping were used to obtain nonlinear mathematical models of the two systems with hydraulic components through the use of an Artificial Neural Network (ANN). For the results, all of the mathematical models presented coefficients of determination, R
, greater than 0.985 for both stiffness and damping, showing an excellent fit for the nonlinear experimental data. Numerical results using a quarter-car suspension model showed a large reduction in vibration amplitudes for the first vibration model when using the hydraulic systems, with values ranging between 48.58% and 66.47%, depending on the tests. The modified system presented smaller amplitudes and smoother behavior when compared to the standard hydraulic model.
In this work, we explore the nonlinear dynamics for capturing energy from a device, which is considered support with cantilever beam ferromagnetic containing piezoceramic patches connected to an ...electrical circuit that collects energy for capture. The free end of the ferromagnetic cantilever beam is under the effect of two magnetic poles, and we consider an asymmetric potential for the magnetic poles. However, the influence of asymmetry in bi-stable energy collectors can change the potential well and adjust the distribution of its potential energy. Charging in the potential well also modifies the unstable equilibrium positions thus altering the dynamic characteristics of the device and thus benefiting the use of energy under various excitation conditions. Furthermore, asymmetric potentials combine with the movement of human lower limbs for applications in energy harvesting devices in such displacement. As numerical results, we explored the nonlinear dynamics and established the sets of parameters for the convergence of the trajectories and the regions of maximum average output power.
In this paper, we investigate a nonlinear dynamic model of the trolling mode in atomic force microscopy (AFM-TR) considering the fractional viscoelasticity. The term fractional viscoelasticity is an ...approximate representation of the medium in which the system is used for the analysis of biological samples. The fractional nonlinear dynamic model of the AFM-TR considers a nanoneedle coupled to a nanobeam that, when subjected to vibrations during the interaction with the sample surface, generates a three-dimensional image of its topology. These interactions between the nanoneedle and sample are Van Der Waals force type, and other interactions are considered biological environment. With these considerations, the fractional dynamics were analyzed considering the Riemann–Liouville fractional derivative operator. The results obtained the intervals in which the system has a chaotic or periodic behavior, such analyses corroborate to determine a set of parameters in which the term of fractional viscoelasticity may influence the dynamics of the AFM-TR.
In the present work, a study was carried out on the dosage of wastes from the chemical industry (tannery sludge) and civil construction (concrete and plaster) in mixtures used in concrete blocks’ ...production. The objective was the application of these blocks in paving. The characterization of the materials used was performed employing X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The effect of the different residues on the blocks’ properties was evaluated through compressive strength, flexion-traction, water absorption, abrasion resistance, and leaching tests. The results indicated that the concrete paving blocks produced with the addition of residues did not obtain gains in the values of mechanical resistance to compression and traction in bending compared to blocks made with standard raw material. However, the blocks produced with construction waste presented satisfactory results for application in street paving after 7 days of concrete curing, reaching values between 36.54 and 44.6 MPa for the mentioned properties. These values also increased to 21.4% within 28 days of curing. The blocks produced with plaster showed values between 37.03 and 39.85 MPa after 28 days of curing, allowing their use for street paving. On the other hand, the blocks containing residues from the chemical industry had lower strengths, reaching a maximum of 29.36 MPa after 28 days of curing. In addition, it was also noted that the blocks produced with recycled concrete showed an improvement in performance for a composition of 50% recycled material.
This paper describes the mathematical modeling corresponding to the kinematics and dynamics of a vehicle with 4-wheels (light vehicles), to determine that the vehicle design meets and guarantees ...better driveability on a local road or highway. The mathematical modeling referring to the kinematics and dynamics (factors influencing vehicle performance) is proposed for traction on the front 2-wheels and for the 4-wheels of the vehicle, allowing to classify the type of vehicle and where it can be implemented. Is presented and justified the computational simulation of kinematic variable that directly influences vehicle dynamics.
We investigated the nonlinear dynamic behavior of the system for energy harvesting using ocean wave motion. The system consists of a linear electromagnetic system coupled to a float to move with ...ocean waves. We define the mathematical modeling of a structure together with the parameters for energy harvesting. In this way, we analyzed average power for the parameters linked to the wave profile, the resistance load of the electromechanical motor, and the nonlinear parameters of spring cubic. Therefore, we also analyze the nonlinear dynamic behavior with Maximum Lyapunov exponent, bifurcation diagrams, phase portraits, and Poincaré maps.
We investigate the nonlinear dynamic model of the Atomic Force Microscopy model (AFM) with the influence of a viscoelastic term. The mathematical model is based on non-resonant and almost linear ...responses, together with the deflection of the microcantilever, and also considers the interaction forces between the atoms of the analysis tip and the sample surface. Our results show the influence on the nonlinear dynamics of this model considering the term viscoelastic. We also analyzed the generalized model with the fractional calculus with the Riemann–Liouville operator derivative applied to the viscoelastic term and thus having the fractional nonlinear dynamics of the AFM system. For the analysis of the system, we used the classic tooling of nonlinear dynamics (Bifurcation diagram, 0–1 Test, and Poincaré maps, and the Maximum Lyapunov Exponent), however, the results showed the chaotic and periodic regions of the fractional system.
This paper was written in honor of Prof. Viktor Olimpanovich Kononenko from Ukraine and takes into account reports of recent progress about non-ideal vibrating systems (NIS) published in the period ...from 2004 to 2017. New and old studies of NIS, with limited power supply (small DC motors or electrodynamical shakers), are usually used in laboratory tests, and therefore, the investigation of mutual interactions of driven and driving sub-system is very important. In this paper, main properties of NIS have been reviewed, such as the Sommerfeld effect, i.e., jump phenomena and the increase in power supply that is required by an excitation source operating near resonance; the possibility of saturation phenomenon occurrence, i.e., the transference of energy from higher frequency and lower amplitude to lower frequency and higher amplitude mode; and the existence of regular (periodic motion) and irregular (chaotic motion) behaviors, depending on the value of control parameters (voltage of a DC motor). This paper is divided into two goals: on the one hand will be treated about NIS and on the other hand will be provided an overview of the main engineering applications, analyzing their physical phenomena involved and the adequate methodologies to deal with them.
PDF
