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This paper presents a simulation model for a preemptive transportation system where vehicles can have tasks dynamically reassigned to optimize overall efficiency. The model, built using Flexsim software, includes 9 storage areas and 8 vehicles. Exponential distributions, validated with real logistics warehouse data, generate stochastic task arrivals. Recursive logic implements the preemption algorithm. Comparative analysis over a 10-hour duration shows that the preemptive mode increases average transport volume by 13 % and reduces vehicle travel distance by 13 % compared to a non-preemptive baseline. The results demonstrate the value of preemptive transportation in enhancing system responsiveness and operational efficiency. [ABSTRACT FROM AUTHOR]

Parallel mechanism is widely used due to its high stiffness, strong bearing capacity, small accumulated error, and good dynamic performance. In this paper, a planar three-degree-of-freedom (3-DOF) redundantly actuated parallel mechanism is proposed. Firstly, the position constraint equation is investigated and the inverse position solution is derived. The center velocity mapping model of the moving platform is established and the Jacobian matrix of the mechanism is obtained. The theoretical model based on Mathematica and the simulation model based on ADAMS are compared to validate the correctness of the theoretical results, and the peak deviation of the results is within 5 %. Then, the constraint conditions are conducted, and the workspace of the mechanism is solved by numerical method. Finally, the influence relationship curves of rod parameters on the proportion of workspace are obtained respectively. And the size parameters are optimized to carry out a comparative analysis of the workspace. [ABSTRACT FROM AUTHOR]