Abstract
Nonlinearities in a container port handling chain include mainly nonnegative arrive rate of container cargoes, limited container handling completion rate, and nonnegative unsatisfied freight requirement constraints. The nonlinearity influences the operation resources availability and consequently the planned container port handling strategies. Developments presented in this work are devoted to a novel design of sliding mode control with low-pass filter (SMC-LPF) to nonlinear handling chain system (HCS) in container ports. The SMC-LPF can effectively reduce unsatisfied freight requirement of the HCS and make chattering decrease significantly. To illustrate the effectiveness and accuracy of the proposed SMC-LPF, an application to a real container port in China is outlined. The performances of the SMC-LPF for the nonlinear HCS in container ports outperform those of the traditional method, particle swarm optimization algorithm, and slide mode control under simulations with a unit step signal and a sinusoidal signal with offset as the freight requirements. The contributions herein demonstrate the proposed control strategy in weakening chattering, reducing the unsatisfied freight requirements to 0 as close as possible in the HCS, maximizing the operation resilience and robustness of port and shipping supply chain against parametric perturbation, external disturbances, and fluctuant handling abilities.
Highlights
Over the last decades, there has been a significant growth of global container transportation due to the fast development of global trade
Our nonlinear model extends the nonlinear model of Xu et al in that our model explicitly considers the unsatisfied freight requirement constraint, whereas the model of Xu et al assumed that the value of the unsatisfied freight requirement may be negative, it does not exist in the actual operation [5]
To reduce chattering in sliding mode control (SMC) and improve the control efficiency, a novel sliding mode control with low-pass filter (SMC-LPF) in Figure 3 is designed for the nonlinear handling chain system (HCS) in container ports. e dashed box contains two parts: the SMC and the LPF, which together form the SMC-LPF system
Summary
There has been a significant growth of global container transportation due to the fast development of global trade. Nonlinearities play an important role in the container port HCS, which is directly related to the production efficiency of terminals and restricts and influences the operation of the other partners in the port and shipping supply chain. Our study adds to the literature by emphasizing three important nonlinearities of the HCS in container ports, which includes nonnegative arrive rate of container cargoes, limited container handling completion rate, and nonnegative unsatisfied freight requirement constraints. E main contributions of this work are as follows: (i) a new nonlinear HCS in container ports is developed, which can be used for container handling with different freight requirements; it helps to improve port service levels. Our study adds to the literature by emphasizing three important nonlinearities of the HCS in container ports, which includes nonnegative arrive rate of container cargoes, limited container handling completion rate, and nonnegative unsatisfied freight requirement constraints. e main contributions of this work are as follows: (i) a new nonlinear HCS in container ports is developed, which can be used for container handling with different freight requirements; it helps to improve port service levels. (ii) A sliding mode control with the low-pass filter (SMC-LPF) for the nonlinear HCS is formulated for efficiently obtaining enhanced solutions, where strategies for coping with nonlinear constraints are proposed, a sliding mode controller with LPF is designed, and exponential reaching law is employed to improve the dynamic quality of the reaching process. (iii) e performance of the SMC-LPF for the nonlinear HCS in container ports is measured and validated by comparing with those of the traditional method, particle swarm optimization algorithm, and slide mode control under simulations on the certain HCS (the values of freight requirements are a unit step signal and a sinusoidal signal with offset, respectively) and uncertain HCS (the uncertainties are parametric perturbation, external disturbances, and fluctuant handling abilities, respectively). e main improvements of the sliding mode control method are (i) a low-pass filter is added to weaken chattering of sliding mode control; (ii) a stable sliding mode motion with the largest sliding mode area is designed; (iii) the upper and lower limits of control signal are well constructed to deal with the nonlinear segments; (iv) the original arate, which reflects the handling requirements, is employed in the design of control signal
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
