The study of damping control in semi-active car suspension

Paper discusses apparently opposing goal functions in terms of car’s comfort and handling. Short descriptions of passive, semi-active and active suspensions with their features are included. Thereafter, employing a two-mass quarter car model, an idea of damping control strategy in semi-active car suspension is presented. The results of performed simulation tests for various inputs are depicted and thoroughly discussed with comparison to classical passive suspension’s response. On the grounds of obtained results, conclusions are formulated. What is more, a layout of further work is outlined, with the aim of system’s response optimization in terms of comfort and handling features, as well as reliable validation of efficiency of proposed damping control strategy

Comparison of the Physicochemical Properties of Carboxylic and Phosphonic Acid Self-Assembled Monolayers Created on a Ti-6Al-4V Substrate

This study compared the tribological properties in nano- and millinewton load ranges of Ti-6Al-4V surfaces that were modified using self-assembled monolayers (SAMs) of carboxylic and phosphonic acids. The effectiveness of the creation of SAMs with the use of the liquid phase deposition (LPD) technique was monitored by the contact angle measurement, the surface free energy (SFE) calculation, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR) measurements. The obtained results indicated that more stable and well-ordered layers, which were characterized by the lowest values of the coefficient of friction, adhesion, and wear rate, were obtained using phosphonic acid as a surface modifier. Based on the obtained results, it was found that the Ti-6Al-4V alloy modified by phosphonic acid would be the most advantageous for practical applications, especially in micro- and nanoelectromechanical systems (MEMS/NEMS)

An experimental device for evaluation of hydrogen sorption

Hydrogen storage for the purposes of the automotive industry in a form other than under high pressure or cryo conditions has been under careful investigation by researchers over past decades. One of the arising methods is the usage of powdered/granulated beds that contain metal hydrides and/or carbon materials to take advantage of the “spillover” phenomenon. Handling and characterization of such material can be troublesome, which is why the experimental setup needs careful investigation. The apparatus for the analysis of hydrogen sorption/desorption characteristics has been successfully designed and described based on the constructed unit within the scope of this article. The full functionality of that setup covered fuelling the bed as well as the examination of sorption/desorption potential. Moreover, the proposed experimental device can clarify many uncertainties about further development and optimization of hydrogen storage materials

Adaptive Tracking PID and FOPID Speed Control of an Elastically Attached Load Driven by a DC Motor at Almost Step Disturbance of Loading Torque and Parametric Excitation

Adaptive tracking control of the speed of a very elastically attached circular load driven by a direct current motor accompanied with an adaptive conventional and a fractional-order Proportional Integral Derivative (PID) controller is studied. It refers to improving the closed-loop control system response of elastically coupled components of drivelines. The motor and the load mechatronic models and the block diagrams are constructed. Parameters of the PID controller in the model reference control are both constant, as well as vary in time. The adaptive control method is improved by the application of a new closed-loop control structure canceling error dynamics. A few competing control strategies are tested based on the application of two types low and high frequency stepwise increasing variations of loading torque and damping coefficient of motion. Moreover, the performance of the control strategies is verified by Integral Time-Weighted Absolute Error (ITAE) index, since their robustness is evaluated by applying a sine modulated triangle waves of selected electric parameters. Therefore, a dynamic forcing and parameter uncertainty is applied. Simulation results are compared for checking the proposed methods

Experimental Study of Drag Torque between Wet Clutch Discs

The development of automatic gearbox control systems contributes to their increasing popularity. By raising the number of gears and sophisticated algorithms, the reduction of fuel consumption is feasible regarding traditional manual transmissions. The continuously variable transmissions (CVT) are also growing their share of the market. Wet clutches are employed in all types of automatic transmissions, but because of oil viscosity, when such a type of clutch is disengaged, the drag torque phenomenon occurs. This deteriorates the global efficiency of the transmission system. To recognize the nature of this drag torque and how it is influenced by the main parameters (distance between plates, value of oil flow rate lubricating clutch, oil temperature, rotational speed between plates), a new test stand has been designed and assembled. The value of rotational speed has been studied up to 7000 rpm which is novel in literature. Due to strongly nonlinear dependences, the achieved results can contribute to designing more efficient clutch systems due to the strongly nonlinear nature of observed phenomena

Experimental Study of Drag Torque between Wet Clutch Discs

The development of automatic gearbox control systems contributes to their increasing popularity. By raising the number of gears and sophisticated algorithms, the reduction of fuel consumption is feasible regarding traditional manual transmissions. The continuously variable transmissions (CVT) are also growing their share of the market. Wet clutches are employed in all types of automatic transmissions, but because of oil viscosity, when such a type of clutch is disengaged, the drag torque phenomenon occurs. This deteriorates the global efficiency of the transmission system. To recognize the nature of this drag torque and how it is influenced by the main parameters (distance between plates, value of oil flow rate lubricating clutch, oil temperature, rotational speed between plates), a new test stand has been designed and assembled. The value of rotational speed has been studied up to 7000 rpm which is novel in literature. Due to strongly nonlinear dependences, the achieved results can contribute to designing more efficient clutch systems due to the strongly nonlinear nature of observed phenomena

Method of reconstructing dynamic load characteristics for durability test Indexed by: of heavy semitrailer under different road conditions

The aim of the article is to present and validate a methodology for collecting road load data on a vehicle, driving on roads and analysis of a drive data signal under the wheel in the time domain, using FRF (Frequency Response Function) and the MTS 320 eight-poster inertia reacted road simulator. The elaborated drive data, was used to control the actuators forcing the movements of the wheels and the coupling part of the semi-trailer during durability tests. The road tests were carried out by registering physical variables in the time domain, by a set of sensors mounted on a vehicle. The data was collected from roads categorized as motorways, national and local roads. Differences between the variability of the parameters, collected on the roads and the variability of the drive data under the wheel, were determined for the particular types of roads, for loaded and unloaded vehicle. The obtained accuracy of reconstruction of the road load data conditions was as high as 97%. Therefore, the proposed method is suitable for reliable durability tests with use of the road simulator