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.
Vibration control for a half-car model with adaptation of the magnetorheological damper model
The paper presents vehicle vibration control using magnetorheological (MR) dampers. Typical algorithms to control this semi-active suspension need the inverse model of the damper. Modelling of the damper is not a trivial task because of its highly non-linear behaviour. Also, effectiveness of damping vibrations caused by the road depends significantly on the quality of the model. Therefore, an identification algorithm based on iterative estimation of immeasurable signals is proposed. Two control algorithms are tested - Skyhook and FxLMS (Filtered-x LMS). Simulation experiments for a half-car model excited by road bumps show usefulness of this approach. It was also observed that the FxLMS is not very sensitive to modelling errors as it includes an internal mechanism of adaptation. On the other hand, the Skyhook fails if the model is inaccurate, so it should be used together with the identification of the MR damper.
An Essay on Modeling: The Social Model of Disability
From its first exposition almost half a century ago, the social model of disability has been aimed at altering both theory and practice, bringing about profound changes in people’s understanding of disability, and in the daily lives of disabled people as well. The social model’s foil, and on some accounts its antithesis, is the medical model of disability. Both models treat disability as a locus of difficulties. While the medical model takes disability to be a problem requiring medical intervention—and as both the prerogative and the responsibility of medical professionals to fix—the social model understands disability as a political problem calling for corrective action by citizen activists who alter other people’s attitudes and reform the practices of the state. These two conceptualizations of disability have been treated as competitors, as if one must prevail over and eradicate the other in thinking about who disabled people are and what should be said and done in regard to them.