Multi-domain unified modeling and simulation of semi-active suspension in magnerorheological damper
In order to build high-precision and highefficient MR damper system model, a multi-domain unified modeling method was proposed. Firstly, based on the analysis of a MR damper semi-active suspension system model, various fields of MR, such as structure, magnetic field, control and mechanics, were studied to find the main influencing parameters. And then for the multi-domain coupling characteristics of MR damper, a multi-domain unified modeling of MR damper system was established based on Modelica/MWorks platform. By adjusting the main influencing parameters, the relationship diagrams between the parameters and the performances were obtained. Finally, some performance results were compared with the traditional method used Matlab/simulink modeling and the method proposed. The results show that the model based on Modelica can preferably reflect the complex relationship between the MR damper coupling among the parameters within the system, and can get a better simulation result.
Behavior of a semi-active suspension system versus a passive suspension system on an uneven road surface
The present paper intends to study the behavior of semi-active suspension systems in comparison with passive suspension systems when subjected to oscillation sources caused by the rolling surface. For this, it was nec-essary to establish the equations specific to the passive and semi-active suspension systems. For each case, the simulation schemes were developed using Matlab Simulink. For the simulation, the quarter car model was chosen. In order to verify the correctness of the model, the State Space and Transfer function models were also used. As the passive dampers have a linear dampening characteristic, we studied the semi-active systems that use magneto-rheological dampers with adjustable characteristics. In the simulation diagram we used a PID controller – proportional integrative derivative. Using two types of stimulus signals we analyzed the behavior of the semi-active suspension system with different dampening coefficients. By simulation, response signals for damper/spring displacement and damper/spring velocity were obtained. The analysis of the obtained results shows the advantages of semi-active systems in comparison with passive systems and the limitations of such systems compared to active systems. DOI: http://dx.doi.org/10.5755/j01.mech.20.1.6591
A new power measuring circuit using a bridge-connected magnetic circuit and another magnetic core
The authors describe the operating characteristics of an oscillating circuit using a bridge-connected magnetic circuit and another magnetic core. A square-shape output voltage is obtained in the oscillating circuit. The pulsewidth in positive and negative half cycles of output voltage changes with the current of the U-form core windings and with the signal voltage applied to the exciting windings. The mean value of the output voltage varies in proportion to the product of the current and the signal voltage. Utilizing this feature, an application of the oscillating circuit to a novel power measuring circuit of simple construction is presented. >