Discrete sliding mode variable structure control over the rotating speed of marine diesel engines

Abstract

This article presents a discrete sliding mode variable structure control used for the speed governing system of marine diesel engines. It is widely accepted that the steady operation of marine diesel engines plays an important role in ensuring the power quality of marine electronic system and good engine performance. In other words, it means that a speed governor with excellent performance is crucial to ensuring the steady rotating speed of a diesel engine. However, due to the fact that diesel engine normally has a complex structure and is often influenced by multiple and nonlinear factors, a traditional proportional integral differential controller cannot optimize the sailing parameters of ships, making it difficult to satisfy the requirements of the speed control for diesel engines under various operation conditions. In view of this problem, this article developed a nonlinear mathematical model of the speed governing system for diesel engines based on experimental tests. Moreover, a discrete sliding mode controller was designed by applying the discrete sliding mode variable structure control, and a simulation model was then developed under the Simulink environment, illustrating that the performance of the designed sliding mode controller is much better than a traditional proportional integral differential controller. Finally, a bench test used for the nonlinear speed governing system based on the discrete sliding mode variable structure control approach was carried out using the bench of a diesel engine Model 2135. The experimental results further illustrated that the discrete sliding mode variable structure controller showed some super advantages, such as smaller overshoot and error, faster response and stronger anti-jamming capability, when comparing with the traditional proportional integral differential controller.