Multi-source Disturbance Observer Based Continuous Sliding Mode Control for Fuel Quantity Actuator System

Abstract

The fuel quantity actuator is a significant component in the position-controlled fuel injection pump, which controls the fuel quantity injected into the diesel engine. In the fuel quantity actuator system, there are nonlinearities and multi-source disturbances which result in significant degradations of control performance and increase the difficulty of control. Previous researches merely consider the constant disturbance in the fuel quantity actuator system but ignore the existing harmonic disturbance, as a result, it is hard to achieve excellent control performance in the presence of harmonic disturbance. This paper analyses the working principle of system in detail, considers multiple sources of disturbances, and then establishes the nonlinear mathematical model with multi-source disturbances including constant disturbances and harmonic ones. Then, a baseline chattering free continuous sliding mode controller is designed. In the baseline controller, the feedback linearization technique is applied to handle the nonlinearities. In order to further reduce the steady-state fluctuation, a multi-source disturbance observer composed of a disturbance observer (DOB) and a harmonic disturbance observer (HDOB) is employed to estimate the multi-source disturbances and the estimations are used for compensation. To this end, a multi-source disturbance observer based continuous sliding mode control approach is proposed. While guaranteeing robustness and free chattering, the steady-state fluctuation is reduced effectively since the switch function gain in the continuous control law can be selected smaller. The simulation validates the proposed control approach.