Control of a 2 DoFs Oscillating Platform Using Pneumatic Actuators

Agricultural tractor operators often suffer from diseases caused by vibrations due to uneven terrain. The Italian National Institute for Insurance against Accidents at Work (INAIL) is interested in minimizing the exposure of these operators to noise and vibration. There are several commercially available suspension systems for seats or cabins that can mitigate the vibrations experienced by the operator. However, these systems are primarily designed to attenuate vertical vibrations, with only few prototype systems developed to counteract the rolling motion of the tractor. The authors have recently proposed a new mechanism capable of reducing both horizontal and rotational vibrations. To asses the performance of the new device, they have designed an oscillating platform that mimics the cabin motion of a tractor moving on an irregular path. This platform’s oscillation is controlled by a pair of pneumatic actuators equipped with proportional flow-rate electro-valves. Assuming knowledge of the transfer function of the electro-pneumatic system, a closed loop control system is developed that is capable of reproducing the profiles of the ISO 5008:2002 standard. The control system is applied to both vertical actuators to reproduce the right and left profile indicated by the standard.