The electrorheological long-stroke damper: A new modelling technique with experimental validation

Semi-active damping devices offer improved performance over passive devices , without the-power requirements or instability problems of fully active de vices. Smart fluids (electrorheological and magnetorheological) are well su ited to use in semi-active dampers-their flow properties can be rapidly alt ered, with a low-power requirement. However, the force/velocity response is :highly non-linear, and this is without doubt hindering the development of effective control strategies. In this paper, the authors develop a new mode l of an electrorheological damper. The key advantage of this model is that its algebraic form is suitable for use in control system design, whilst it is able to predict and explain observed behaviour. The model consists of a spring, mass, and damper connected. in series. The spring stiffness term is based upon the fluid bulk modulus, and:the mass is determined from the flu id density. The damping characteristic utilizes a-modified nondimensional B ingham Plastic function. The model predictions are compared with experiment al results at a range of operating frequencies. Excellent agreement was ach ieved by updating the stiffness and viscosity parameters using experimental data. (C) 2000 Academic Press.