Abstract

In this thesis a mathematical model is developed in order to describe the dynamics of the variable geometric volume swash plate axial piston pumps with the conical cylinder blocks and the integrated control unit. Using the validated model, an analytical study was conducted in order to investigate the effect of the port plate configuration on pump performance. Simulation of the change in the cylinder pressure and pump flow rate, in a systematic sequential procedure, led to an improved geometry for the suction and delivery silencing grooves on the valve plate. Cavitaion in the cylinder and pump noise were also reduced with the improved geometry. Force and vibration analysis of the pumping mechanism were carried out. This analysis presents some design recommendations regarding the moments acting on the swash plate, dynamic loads acting on the drive shaft bearings and the advantages and the limitations of using the conical arrangement of the pistons. Pump performance is simulated using a conventional PD controller with double negative feedback loop to control the swash plate swiveling angle, as currently used in practical applications. An introductory study of implementing other control schemes is conducted. A fuzzy controller is proposed to replace the PD controller in a double feedback control loop in order to improve the robustness of the control action. A single feedback control loop is proposed to replace the double control loop in order to suppress the steady state vibration of the swash plate. The control schemes were prototyped using specially developed real-time control techniques on a personal computer. The experimental setup is also used to verify the analytical findings of the pump performance with the newly proposed control schemes.