•A fuzzy robust facility layout problem is described.•Cranes are considered in the plant region.•Two proposed meta-heuristic algorithms were used to solve the problem.
Facility layout problems are ...defined as the placement of facilities in a plant region. In this paper a facility layout problem was clarified by the facility dimensions and the materials flow between facilities are uncertain as fuzzy random variables and the plant region was equipped with the wall mounted jib cranes and the small gate cranes and there were some forbidden areas in the plant region where the placement of facilities were forbidden. The objective functions of the problems have been contemplated as minimizing materials handling cost of the operators and the cranes and for the first time maximizing cranes usability of wall mounted jib cranes and small gate cranes by calculating their covered area on the facilities. To solve the problem a multi-objective population-based on simulated annealing algorithm (MPS) and a Modified Non-dominated Sorting Genetic Algorithm II (MNSGA-II) was proposed then six case studies were solved by them. The results reveal that run time of the MNSGA-II for large size problems are better than the MPS algorithm and the MPS algorithm finds better solutions with materials handling cost of the operators and the cranes and the MNSGA-II finds better solutions with cranes usability.
In container sea–rail combined transport, the railway yard in an automated container terminal (RYACT) is the link in the whole logistics transportation process, and its operation and scheduling ...efficiency directly affect the efficiency of logistics. To improve the equipment scheduling efficiency of an RYACT, this study examines the “RYACT–train” cooperative optimization problem in the mode of “unloading before loading” for train containers. A mixed-integer programming model with the objective of minimizing the maximum completion time of automated rail-mounted gantry crane (ARMG) tasks is established. An adaptive large neighborhood search (ALNS) algorithm and random search algorithm (RSA) are designed to solve the abovementioned problem, and the feasibility of the model and algorithm is verified by experiments. At the same time, the target value and calculation time of the model and algorithms are compared. The experimental results show that the model and the proposed algorithms are feasible and can effectively solve the “RYACT–train” cooperative optimization problem. The model only obtains the optimal solution of the “RYACT–train” cooperative scheduling problem with no more than 50 tasks within a limited time, and the ALNS algorithm can solve examples of various scales within a reasonable amount of time. The target value of the ALNS solution is smaller than that of the RSA solution.
Background: By investigating accidents in industries, it can be concluded that a significant proportion of work-related accidents occur in the construction industry. The present study aimed to apply ...a hybrid model in identifying and prioritizing risks in a construction project with new machinery.
Methods: In this study, the methodological shortcomings of the traditional failure mode and effects analysis (FMEA) method and the need to prioritize control measures were modified by the analytical hierarchy of process (AHP). The FMEA was used for risk identification and risk assessment in the elevated highway construction project, then AHP accidents were prioritized according to their physical, psychological, economic, and socio-political burden.
Results: In the AHP structure, several sub-criteria for each criterion were considered and weighted for each item. The five activities included crane collapse, falling from a height, collapse, and electrocution devices that their risk priority number is more than 250 weighted by the AHP.
Discussion: Based on the literature, the traditional FMEA has many shortcomings that need to be corrected by other methods. This study aimed to modify the traditional FMEA method using a hybrid model.
Conclusion: The findings of this study showed that in urban projects, hazards threaten workers, citizens, and company properties. In addition to accidents, deaths, and injuries, they have negative consequences, such as health, psychological, economic, and socio-political impacts. Accidents cause loss of human life, worker's mental health problems, damage to equipment or property, worker's productivity loss, and affect the profit and reputation of the organization. Due to many deficiencies of the conventional risk priority number (RPN) in the FMEA method, it was criticized, and to enhance the performance of the FMEA in risk analysis, various risk priority models have been proposed.
In this article, two boundary feedback controllers are designed via the backstepping approach for a class of gantry crane systems. To provide an accurate and concise representation of the dynamic ...behavior, the gantry crane with a flexible cable is described by a hybrid system. The hybrid system is formed by an ordinary differential equation coupled with a partial differential equation. In the first control strategy, a backstepping-based boundary state-feedback controller is proposed for the gantry crane to transport a payload to an expected position with less shaking. In the second control strategy, a boundary output-feedback controller is explored with an observer estimating the inaccessible states. By using the backstepping technique and kernel functions, the original systems with different control strategies are transformed into target systems. By using the operator semigroup and Lyapunov stability theories, the target system is proven to be well-posed and exponentially stable, respectively. Finally, numerical simulations and comparisons are provided to illustrate the efficiency and the advantages of the proposed methods.
Gantry cranes are widely used in transporting heavy loads in construction projects and critical industries such as petrochemical industry and nuclear power stations. Their mission should be ...accomplished with as high accuracy for the trolley positioning, and minimum values of sway oscillation angles as possible. So, the control strategies aim to achieve high productivity (through transporting the trolley with good precision) while considering safety precautions (through eliminating sway oscillations). One of the linear closed loop control methods is using PD and PID controllers. This research provides a non-linear mathematical model for single-pendulum gantry crane with two stable control schemes that depend on PID and PD controllers equipped with inlet derivative filter for every scheme. The two control schemes utilize a PID controller for positioning the trolley and a PD controller for eliminating undesired sway angles of the payload. In the second scheme, the input voltage control signal is always saturated to be positive to preserve the direction of rotation of the driving DC motor. The controllers include up to five gains and two inlet derivative filter coefficients which are tuned using Multi-Objective Genetic Algorithm (NSGA-II) with four different fitness functions and one weighted function to choose a suitable solution from other Pareto solutions. The simulation results are presented to show the superiority of the second scheme precision in trolley transporting with minimum payload sway oscillations.
A timely damage state assessment of gantry cranes has a significant impact on the post-earthquake reconstruction and economic recovery in earthquake-stricken areas. This study aims to propose a ...methodology to rapidly predict the seismic damage states in light of nine classification-based machine learning methods. The 48 earthquake parameters is presented and of which relative importance and influence on the structural responses of the employed simple gantry crane are examined based on the data set matrix of 2760 (ground motions) ×48 (earthquake parameters). Meanwhile the innovative method is proposed to mitigate the class imbalance problem in the training data. Finally, the proposed method is applied to predict the fragility of a gantry crane subjected to ground motions and the efficiency and accuracy of nine machine learning methods are compared herein. The results demonstrate that the parameter of spectral acceleration S
a
at the first self-vibration period of the examined structure is of great significance to predict the accurate damage states. Random Forest, Neural Networks, Logistic Regression, and Support Vector Machine are preferable in all selected machine learning methods hereon. And the predictive fragility curves and the fragility curves computed in FE model are consistent approximately in spite of maximum error of 7.5%.
This paper presents simulation and real-time implementation of input-shaping schemes with a distributed delay for control of a gantry crane. Both open-loop and closed-loop input-shaping schemes are ...considered. Zero vibration and zero vibration derivative input shapers are designed for performance comparison in terms of trolley position response and level of sway reduction. Simulation and experimental results have shown that all the shapers are able to reduce payload sway significantly while maintaining satisfactory position response. Investigations with different cable lengths that correspond to ±20% changes in the sway frequency have shown the distributed delay-based shaper has asymmetric robustness behaviour. The shaper provides highest robustness for the case of 20% increase in the sway frequency but lower robustness for the case of 20% decrease. However, other schemes give symmetric robustness behaviour for both cases.
This paper proposes an experimental verification of a hybrid partial feedback linearization (PFL) and deadbeat (DB) control scheme as in Hamdy et al. (2018) with chaotic whale optimization algorithm ...(CWOA) for a nonlinear gantry crane (GC) system. The PFL linearizes the nonlinear model to end up with a linear closed-loop system. The DB controller is utilized for the desirable accelerated response without any oscillation or undesirable effects on the internal dynamics stability. The CWOA is used to tune the controller parameters. A sliding-mode observer (SMO) is utilized to estimate the unmeasured states. Using this hybrid scheme, a better payload sway elimination can be obtained. Finally, the experimental results are presented to illustrate the efficiency and the effectiveness of the proposed scheme with a comparative study.
•Experimental verification of a hybrid PFL and DB control scheme for a nonlinear GC.•PFL gains are tuned by CWOA while SMO is introduced to estimate unmeasured states.•Experimental results guarantee the practicability with a comparative study.
A gantry crane is widely used in industries for transportation of heavy loads, but control of this system for a fast operation is challenging. This paper presents the application of pole placement ...controller for controlling a 2D gantry crane system to achieve minimum sway angle and accurate positioning of payload by varying poles location. A linearized model of the system is obtained, and a pole placement controller is designed with three poles located at different locations on the left-hand side of the s-plane. Simulation via MATLAB and Simulink was performed to investigate the performance of the pole placement controller. Simulation results have shown that when both the dominant and other poles are chosen to be complex poles, then a better performance of the system will be achieved.
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