Papers by Keyword: Suspension

Abstract: It is known that for automotive semi-active suspension the damping of shock absorber shall be continuously adjustable. One approach for damping adjustment is via adjusting flow area of throttle valve of shock absorber using stepping motor. Throttle valve can be realized using electro-magnetic valve or any other type of driving valve. In order to be applied on semi-active suspension, the throttle valve is required to have high control precision, fast response speed, strong anti-pollution capability and etc.. In this paper a new type of digital valve is presented to control the flow area of shock absorber. The configuration is developed by the utilization of the two-motions-degree of freedom of a single spool. To solve the contradiction between the response speed and the quantitative accuracy which characterizes the previous valve of the same sort, a specially designed tracking program is adopted to the stepping motor control to smooth displacement output. Experimental results show that both static and dynamic performances of the digital valve can fulfill the requirement of semi-active suspension, which is valuable in the application of system such as semi-active suspension where the liquid flow needs to be controlled rapidly and accurately.

Abstract: In this paper, a semi-active suspension system has been proposed to improve the ride comfort, and a 2 DOF vehicle system is designed to simulate the actions of vehicle suspension system. The purpose of a suspension system is to support the vehicle body and increase ride comfort. The aim of the work described in the paper was to illustrate the application of fuzzy logic technique to the control of a continuously damping automotive suspension system. The ride comfort is improved by means of the reduction of the body acceleration caused by the car body when road disturbances from smooth road and real road roughness. Based on MATLAB fuzzy control toolbox, fuzzy controller is designed. Simulation analysis of suspension system is preceded by using MATLAB/Simulink7.0. The result shows that this control can improve the body acceleration, suspension distortion etc.

Abstract: Based on Multi-body system Dynamic theory, front suspension model is established by using ADAMS/Car, and then the validation is finished according to suspension K&C test project. Through the model simulation, the sensitivity of structure parameters to suspension kinematics characteristics has been analyzed and then the most sensnetive ones have been sorted out. The suspension structure geometry parameters are optimized by the application of DOE method based on virtual prototype technology. The parallel travel simulation results are as follows: the values of camber angle, toe angle, kingpin inclination angle, steer angle and lift/dive are reduced, and the values of caster angle are increased slightly with the optimized suspension. Consequently, the optimized suspension is more conducive to vehicle handling stability compared with the original one. This optimization design method provides the technical support for suspension positive development.

Abstract: A new control algorithm combing Reduced-order observer, LQG and Fuzzy Logic Controller (RLFLC) is proposed to compromise the classical suspension conflict between riding comfort and driving safety. The RLFLC optimizes the weights of the performance indexes on line in accordance with variational suspension deflection and body acceleration to schedule the gain of LQG controller dynamically for achieving multiple control objectives. In particular, a reduced-order observer is introduced to estimate some state variables which are difficult to measure. Compared with the passive suspension and the conventional LQG control system, the simulation results show that RLFLC can be adaptive to vehicle speed and road conditions to improve not only the riding comfort at low speeds, but also driving safety at high speeds without violating the given suspension deflection limit

Abstract: The performance of the dispersion of cobalt blue in organic solvent is studied. The influence of dispersant (type & dosage), pH value, and other dispersion parameters on the stability of cobalt blue dispersion system is tested which shows good stability and excellent dispersion performance with diethylamide glycol ether the solvent, complex formulation (M (KH550): M (KH560): M (A-842) = 1:1:2) the dispersant and 7 the pH value. The characteristics of dispersion system are evaluated through sedimentation experiment and measurement of article size distribution. The most steady dispersion system is formed through high speed shearing force and the size of cobalt blue in this system is about 300nm.

Abstract: This paper is to present a new semi-suspension that is designed for Omni-directional four wheels-driven electric vehicles. With the use of band spring and lower cross arm this kind of suspension is characterized by the simply and compactly structure, flexible steering and better loading capacity. A prototype is designed and built based on the geometric model and mathematical description using Matlab.

Abstract: The rubber mount components in suspension system have great influence on ride comfort of automobile. Based on the complex stiffness model and equivalent model of shock absorber rubber mount, the suspension system model with 2DOF including rubber mount components are established by using virtual coordinate. The influences of the stiffness of rubber mount component on the responses of suspension are analyzed in frequency and time domains. The results show that proper stiffness of rubber mount can decrease the acceleration of body by about 20% and dynamic load of tire by about 30% in the frequency range from 5 to 12 Hz compared with that without rubber mount. In addition, the stiffness of rubber mount component leads to lag acceleration of body and higher nature frequency of wheel.

Abstract: In this article, we demonstrate how the non ionic polymer, the polyethylene oxide (PEO) with molecular weight 6000 g/mol of varying concentration mass (0.7%, 1%, 2% et 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions (6%) in the water. The different rheological tests made in simple shear and in dynamic on the ternary system (water-bentonite-PEO), showed the influence of the polymer on the rheological properties of this drilling fluid. The PEO which presents an affinity for the bentonite particles slows down the kinetic of aggregation of the clay particles. Also the analysis by X-rays diffraction on different samples revealed the intercalation of the clay platelets on one hand and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand. The Herschel-Bulkley rheological model is used for the correlation and the interpretation of our experimental results.

Abstract: The existence of center towers is the origin of performance difference between multi-tower suspension bridge and the traditional one, and longitudinal stiffness of the center tower is a decisive factor. Based on the finite element theory, the paper establishes numerical calculation model of multi-tower suspension bridge, and analyzes it’s static and dynamic performance variation by using different longitudinal flexural stiffness. Moreover, the factors that affect center tower stiffness are determined. Referring to judgment standards about usability and structure security given by existing research, the reasonable range of center tower stiffness is established. Besides, the paper tries to ascertain reasonable center tower stiffness by using the static mechanic performance of service phase as judgment standards.

Abstract: A new method was presented to study the content of the soluble alkali in mortar. The method was based on mixing powdered sample with distilled water with two water-solid ratios and measur-ing the pH of the suspension. According to the measurement result of the suspension, the content of soluble alkali in mortar was calculated. The parameters such as water-solid ratio and measuring ac-curacy which affected the calculated result were investigated. The calculated result of the content of soluble alkali in mortar was compared with the result of flame photometry. The calculation was in good agreement with the result of flame photometry.