This paper is focused on the problem of active suspensions of wheeled vehicles with electro-hydraulic actuators. Two dynamic structures first with actuator connected with spring in series and second in parallel – called slow active and full active respectively – were considered. The considerations described in the paper concern physical quarter-vehicle models of suspensions. These models were constructed and installed on a rig for dynamic tests of structures. A laboratory rig enables the simulation of real conditions by disturbing investigated suspension by kinematic excitation. Research was carried out for various algorithms controlling the actuator of the active unit. For evaluation of laboratory research results, comparisons were proposed of frequency response functions and of time curves of instantaneous power taken by the active system from supply, obtained at the same excitation signals. Quantitative aggregated indicators in the form of an averaged coefficient of vibration transmissibility and power required for the active unit to achieve vibration transmissibility function were also proposed.

Laboratory investigations of an active vehicle suspension of an in-series structure of the slow-active type are presented in this paper. The multidimensional model is reduced to a case representing quarter car suspension. Control laws for active vibration reduction systems are usually determined based upon linear models of objects. Active suspensions are characterised by nonlinearity, connected most often with actuating systems and their energetic restrictions. This causes divergences between theoretical quality factors and those determined experimentally. The second essential problem is finding a compromise between opposed quality factors (for example, minimum power requirement and high efficiency of vibration reduction). Thanks to the use of the proper control law in the active vibration reduction system of vehicle suspension, the goal of ensuring a high level of ride comfort, good vehicle handling and incessant contact of the wheels with the road surface with a minimum power requirement may be attained. The authors, in seeking a compromise, determined classical LQR controllers for the proposed quality indicators realising the aims mentioned above. These controllers are determined for a linearised suspension model obtained from identification. Experimental characteristics are determined for all of the suspension control systems.

Use of springs made of an alloy with shape memory (SMA) to shape the dynamic characteristics of a resonance vibration screen is proposed in this paper. These springs change spring constant as a result of temperature changes. Thus it is possible to change their resonance frequency in real time. In the paper a mathematical model of a controlled SMA spring was formulated and its parameters were identified. In the model both the effect of spring coefficient changes and damping changes depending upon alloy temperature and spring vibration frequency were taken into consideration. Experimental investigations of the examined spring and screen physical model were carried out and selected characteristics were also included. The investigations were carried out at the Dynamics and Control of Structures Laboratory of AGH University of Science and Technology. The control law was formulated. Simulation investigations of the mathematical vibration screen model in both open and closed loop systems were made. It was shown that the elaborated control system is robust of vibration mass changes by as much as ±30%.

The paper summarizes the methods of a tracked vehicles model construction in MSC.ADAMS program. Advantages and faults of these methods are described here. Finally, the authors describe one chosen method with exact elements geometry of the chosen real suspension parts. Basis on this method, a construction of the tracked vehicle model is described. Parts of this model are parameterized and can be fluently changed with usage of a dedicated user interface. Next, a part of the tracked vehicle simulation results is presented.