CONTROL ALGORITHMS FOR ACTIVE CAB SUSPENSIONS ON AGRICULTURAL TRACTORS

This paper describes active agricultural tractor cab suspensions based on optimal control theory. Control algorithms based on time invariant state feedback and on adaptive control are developed and studied. The influence of different observers and measurement noise levels on the vibration damping capacity are studied as well as the power consumptio n for the suspensions. The principle for the adaptive algorithm is bas ed on the parameters in the penalty matrices being varied so that the resulting controller always strives to make optimum use of available t ravel space. The feedback and observer gains are also changed dependin g on the characteristics of the vehicle's frame movements. The results show that it is possible to design an effective active suspension, bu t that the choice of feedback gains must be dependent on the surface c haracteristics to reach satisfactory vibration damping performance.