Fractional PID controller in an active image stabilization system for mitigating vibration effects in agricultural tractors

Recent demands in sophisticated agricultural machinery require passive or active image sensors to be mounted on vehicle frames. The impact produced by vertical displacements due to tire-soil interaction and mechanical engine vibration causes oscillations that reduce the data quality of any activity performed by equipment such as a camera, spectroradiometer, or scanner laser. This paper presents the modeling and simulation of an active system for stabilization of oscillations using a fractional order PID (Proportional-Integral-Derivative) controller. A method for tuning the fractional order PID is presented for a closed-loop dynamic system. Experiments based on simulations are carried out to compare the performance of the active stabilization system with fractional and integer order PID controllers. Common excitation functions are used to assess the performance of the active stabilization system, along with some common vibration disturbances acquired by a field experiment with a tractor-implement set. The results show that the active stabilization system presents better performance, mitigating vibration displacements and accelerations through a closed-loop system with a fractional PID controller. Additionally, numerical results confirm the superior capacity of the fractional controller based system for attenuating the vibration disturbance compared to the classical PID system for different machinery operational conditions such as forward speed and load.