Active vibration reduction operator’s seat with the use of controlled single-acting pneumatic actuator

Mobile heavy machines produce vibrations with low natural frequencies. Because they tend to ride at low speeds, excitations due to road roughness excite low frequency vibrations, which can be reduced by active or semi active methods only. Under conditions of low frequency vibrations, energy dissipation in tires will reduce the vibration intensity in a minor degree only. In the unsprung mobile machine vibration isolation system are provided between a vibration source and the protected object (operator) along the path of vibration propagation. Most machines are now equipped with controlled suspension seats. In the case of active suspensions, the external energy source is required, for instance in the form of compressed air. The compressed air has the advantage that it is generally available in heavy machines as the working fluid and is environmentally friendly. Simulation tests were carried out both in the time domain in Matlab-Simulink and in the frequency domain in the program Mathcad. Simulation tests were performed to investigate effectiveness and stability of the proposed solution and the results were deemed satisfactory. The system was found to be feasible and implementable with respect to every parameter. The first purpose of this study is to develop a simulation model of the active suspension of operator's seat based on an adjustable pneumatic actuator. The other purpose of this study is to examine the effectiveness of different control strategies.