International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In the paper, the design of a linear motor as an actuator in vehicle active suspension systems will be presented. The attention is focused on several interesting design aspects of a non-traditional actuator (a linear synchronous permanent magnet motor with electronic commutation) controlled to obtain a variable mechanical force for a car active suspension. The main advantage of such a solution is the possibility to generate desired forces acting between the unsprung (wheel) and sprung (car body) masses of the car, providing good insulation of the car sprung mass from the road surface disturbances. In addition, under certain circumstances it is possible to reduce or even eliminate the demands concerning the external power source.

In the paper, energy recuperation and management in automotive suspension systems with linear electric motors controlled using a proposed H∞ controller to obtain a variable mechanical force for a car damper is presented. Vehicle suspensions in which forces are generated in response to feedback signals by active elements obviously offer increased design flexibility compared to the conventional suspensions using passive elements such as springs and dampers. The main advantage of the proposed solution using a linear AC motor is the possibility to generate desired forces acting between the unsprung and sprung masses of the car, providing good insulation of the car sprung mass from the road surface disturbances. In addition, under certain circumstances using linear motors as actuators enables to transform mechanical energy of the vertical car vibrations to electrical energy, accumulate it, and use it when needed. Energy flow control (management) enables to reduce or even eliminate the demands concerning the external power source.

In the paper, fuzzy logic is used to simulate active suspension control of a one-half-car model. Velocity and acceleration of the front and rear wheels and undercarriage velocity above the wheels are taken as input data of the fuzzy logic controller. Active forces improving vehicle driving, ride comfort and handling properties are considered to be the controller outputs. The controller design is proposed to minimize chassis and wheels deflection (sky-hook concept) when uneven road surfaces, pavement points, etc. are acting on tires of the running car. As a result, a comparison of an active suspension fuzzy control and a spring/damper passive suspension is shown using MATLAB simulations.