Model identification of active pneumatic vibration reduction operator’s seat of mobile machines

Low-frequency vibrations, generated in mobile machines during their driving, could be reduced only by use of active or semiactive methods. In conditions of low-frequency vibrations, energy dissipation in the machines tires slightly reduces the intensity of the vibration. Unsprung mobile machines are usually equipped with system of vibration isolation, which is located on the way of vibration propagation, between the vibration source and the protected object (the operator of the machine). Generally, controlled seat suspension is used. In the case of the active suspensions, it is necessary to provide external energy, e.g., in the form of compressed air. The compressed air has the advantage that it is generally available in working machines as the working fluid and has its environmentally friendly properties (leaks do not contaminate the environment). This article is the result of the continuation of work on active methods of vibro-activity lowering in mobile machines, which resulted in, among others, elaboration of simulation model of the active operator’s seat suspension with controlled pneumatic actuator. Currently aim of the study was experimental verification of the theoretical results; this verification was performed on the laboratory test bench. In the stand tests, special attention was paid on the assumed models of friction and thermodynamic phenomena in pneumatic actuator, as well as on the control system. Experimental tests were carried out under conditions of harmonic excitations, coming from the electromechanical vibration exciter with controllable pitch and frequency. Data acquisition system and control circuit of the proportional directional control valve, supplying compressed air to the actuator were implemented using Matlab-Simulink Real-Time software. Identification of the simulation model allows for getting the right parameters of the seat suspension. In addition, parametric optimization of the seat suspension system and functional optimization of control strategy would be possible in the next step.