SimPy仿真：集装箱码头如何保证单个集装箱卸货和顺序运输？

标签：python asynchronous simulation simpy

我正在对集装箱码头进行 SimPy 模拟，船舶到达、停泊并使用起重机卸载集装箱，然后使用卡车进行运输。问题陈述_pt1 、问题陈述_pt2

我需要确保：

每台起重机一次仅卸载一个集装箱。
在有空卡车可用之前，起重机应继续其卸载过程，无论之前的卡车是否已完成转运。
如果没有卡车如果可用，则起重机需要等待才能开始卸载集装箱。

simulation.py

import simpy
from vessel import Vessel
from config import *
import random

class Simulation:
    def __init__(self, simulation_time):
        self.env = simpy.Environment()
        self.simulation_time = simulation_time
        self.berth_resource = simpy.Resource(self.env, capacity=NUM_BERTHS)
        self.crane_resource = simpy.Resource(self.env, capacity=NUM_CRANES)
        self.truck_resource = simpy.Resource(self.env, capacity=NUM_TRUCKS)
        
    def generate_vessels(self):
        vessel_id = 1
        while True:
            yield self.env.timeout(random.expovariate(1 / (AVERAGE_INTERARRIVAL_TIME * 60)))  # time between arrivals
            vessel = Vessel(self.env, vessel_id, self.berth_resource, self.crane_resource, self.truck_resource)
            print(f"Time {self.env.now}: Vessel {vessel_id} arrives.")
            self.env.process(vessel.process())
            vessel_id += 1
            print(f"Time {self.env.now}: Number of vessels waiting for berths: {len(self.berth_resource.queue)}")
            print(f"Time {self.env.now}: Number of vessels currently being served at berths: {self.berth_resource.count}")
            print(f"Time {self.env.now}: Number of cranes currently being used: {self.crane_resource.count}")
            print(f"Time {self.env.now}: Number of trucks currently being used: {self.truck_resource.count}")
            
    def run(self):
        """Run the simulation"""
        self.env.process(self.generate_vessels())
        self.env.run(until=self.simulation_time)

vessel.py



import random
import simpy
from config import NUM_CONTAINERS, AVERAGE_INTERARRIVAL_TIME, CRANE_LIFT_TIME, TRUCK_CYCLE_TIME

class Vessel:
    def __init__(self, env, id, berth_resource, crane_resource, truck_resource):
        self.env = env
        self.id = id
        self.containers = NUM_CONTAINERS
        self.berth_resource = berth_resource
        self.crane_resource = crane_resource
        self.truck_resource = truck_resource
        self.container_queue = simpy.Store(env)  # Queue to hold unloaded containers

    def berth(self):
        """Simulate vessel berthing"""
        with self.berth_resource.request() as request:
            yield request
            print(f"Time {self.env.now}: Vessel {self.id} starts berthing.")
            print(f"Time {self.env.now}: Vessel {self.id} finished berthing.")
            yield self.env.process(self.unload())

    

    
    def unload_container(self, container_id):
        """Simulate unloading a single container"""
        print(f"Time {self.env.now}: Vessel {self.id} requests crane for container {container_id + 1}.")
        with self.crane_resource.request() as crane_request:
            yield crane_request
            print(f"Time {self.env.now}: Quay crane starts unloading container {container_id + 1} from vessel {self.id}.")
            yield self.env.timeout(CRANE_LIFT_TIME)  # Crane time to unload one container
            print(f"Time {self.env.now}: Quay crane finished unloading container {container_id + 1} from vessel {self.id}.")
            yield self.container_queue.put(container_id)  # Add the unloaded container to the queue
            # Start the transport process for this container after unloading
            self.env.process(self.transport_container(container_id))

    def transport_container(self, container_id):
        """Simulate the transport of a container by a truck"""
        print(f"Time {self.env.now}: Vessel {self.id} requests truck for container {container_id + 1}.")
        with self.truck_resource.request() as truck_request:
            yield truck_request
            print(f"Time {self.env.now}: Truck starts transporting container {container_id + 1} from vessel {self.id}.")
            yield self.env.timeout(TRUCK_CYCLE_TIME)  # Truck time to transport the container
            print(f"Time {self.env.now}: Truck finished transporting container {container_id + 1} from vessel {self.id}.")

    def unload(self):
        """Unload all containers from the vessel"""
        unload_processes = [self.env.process(self.unload_container(i)) for i in range(self.containers)]
        for process in unload_processes:
            yield process  # Wait for all unload processes to finish
        print(f"Time {self.env.now}: Vessel {self.id} has been fully unloaded and leaves the berth.")

    
    def process(self):
        """Process the entire sequence of arrival, berthing, and unloading"""
        yield self.env.process(self.berth())

输出：

Enter the number of hours to run the simulation: 3
Time 104.4311467616123: Vessel 1 arrives.
Time 104.4311467616123: Number of vessels waiting for berths: 0
Time 104.4311467616123: Number of vessels currently being served at berths: 0
Time 104.4311467616123: Number of cranes currently being used: 0
Time 104.4311467616123: Number of trucks currently being used: 0
Time 104.4311467616123: Vessel 1 starts berthing.
Time 104.4311467616123: Vessel 1 finished berthing.
Time 104.4311467616123: Vessel 1 requests crane for container 1.
Time 104.4311467616123: Vessel 1 requests crane for container 2.
Time 104.4311467616123: Vessel 1 requests crane for container 3.
Time 104.4311467616123: Vessel 1 requests crane for container 4.
Time 104.4311467616123: Vessel 1 requests crane for container 5.
Time 104.4311467616123: Vessel 1 requests crane for container 6.
Time 104.4311467616123: Vessel 1 requests crane for container 7.
Time 104.4311467616123: Vessel 1 requests crane for container 8.
Time 104.4311467616123: Vessel 1 requests crane for container 9.
Time 104.4311467616123: Vessel 1 requests crane for container 10.
Time 104.4311467616123: Quay crane starts unloading container 1 from vessel 1.
Time 104.4311467616123: Quay crane starts unloading container 2 from vessel 1.
Time 107.4311467616123: Quay crane finished unloading container 1 from vessel 1.
Time 107.4311467616123: Quay crane finished unloading container 2 from vessel 1.
Time 107.4311467616123: Vessel 1 requests truck for container 1.
Time 107.4311467616123: Vessel 1 requests truck for container 2.
Time 107.4311467616123: Truck starts transporting container 1 from vessel 1.
Time 107.4311467616123: Truck starts transporting container 2 from vessel 1.
Time 107.4311467616123: Quay crane starts unloading container 3 from vessel 1.
Time 107.4311467616123: Quay crane starts unloading container 4 from vessel 1.
Time 110.4311467616123: Quay crane finished unloading container 3 from vessel 1.
Time 110.4311467616123: Quay crane finished unloading container 4 from vessel 1.
Time 110.4311467616123: Vessel 1 requests truck for container 3.
Time 110.4311467616123: Vessel 1 requests truck for container 4.
Time 110.4311467616123: Truck starts transporting container 3 from vessel 1.
Time 110.4311467616123: Quay crane starts unloading container 5 from vessel 1.
Time 110.4311467616123: Quay crane starts unloading container 6 from vessel 1.
Time 113.4311467616123: Truck finished transporting container 1 from vessel 1.
Time 113.4311467616123: Truck finished transporting container 2 from vessel 1.
Time 113.4311467616123: Quay crane finished unloading container 5 from vessel 1.
Time 113.4311467616123: Quay crane finished unloading container 6 from vessel 1.
Time 113.4311467616123: Vessel 1 requests truck for container 5.
Time 113.4311467616123: Vessel 1 requests truck for container 6.
Time 113.4311467616123: Truck starts transporting container 4 from vessel 1.
Time 113.4311467616123: Truck starts transporting container 5 from vessel 1.
Time 113.4311467616123: Quay crane starts unloading container 7 from vessel 1.
Time 113.4311467616123: Quay crane starts unloading container 8 from vessel 1.
Time 116.4311467616123: Truck finished transporting container 3 from vessel 1.
Time 116.4311467616123: Quay crane finished unloading container 7 from vessel 1.
Time 116.4311467616123: Quay crane finished unloading container 8 from vessel 1.
Time 116.4311467616123: Vessel 1 requests truck for container 7.
Time 116.4311467616123: Vessel 1 requests truck for container 8.
Time 116.4311467616123: Truck starts transporting container 6 from vessel 1.
Time 116.4311467616123: Quay crane starts unloading container 9 from vessel 1.
Time 116.4311467616123: Quay crane starts unloading container 10 from vessel 1.
Time 119.4311467616123: Truck finished transporting container 4 from vessel 1.
Time 119.4311467616123: Truck finished transporting container 5 from vessel 1.
Time 119.4311467616123: Quay crane finished unloading container 9 from vessel 1.
Time 119.4311467616123: Quay crane finished unloading container 10 from vessel 1.
Time 119.4311467616123: Vessel 1 requests truck for container 9.
Time 119.4311467616123: Vessel 1 requests truck for container 10.
Time 119.4311467616123: Truck starts transporting container 7 from vessel 1.
Time 119.4311467616123: Truck starts transporting container 8 from vessel 1.
Time 119.4311467616123: Vessel 1 has been fully unloaded and leaves the berth.
Time 122.4311467616123: Truck finished transporting container 6 from vessel 1.
Time 122.4311467616123: Truck starts transporting container 9 from vessel 1.
Time 125.4311467616123: Truck finished transporting container 7 from vessel 1.
Time 125.4311467616123: Truck finished transporting container 8 from vessel 1.
Time 125.4311467616123: Truck starts transporting container 10 from vessel 1.
Time 128.4311467616123: Truck finished transporting container 9 from vessel 1.
Time 131.4311467616123: Truck finished transporting container 10 from vessel 1.

问题：

我无法同时满足要求 1 和2.最初我没有想到起重机在卡车转运时同时卸货，我能够在该限制下运行模拟。

提到的实现能够独立运行卸载和转运过程，但我无法解决两个集装箱能够同时使用起重机或卡车的问题（如输出中突出显示的）

我尝试过的：

顺序处理集装箱卸载和运输，但仍然面临同时卸载的问题。任何有关如何纠正此问题的指导或建议将不胜感激。

所需的输出：

Enter the number of hours to run the simulation: 3
Time 1: Vessel 1 starts berthing.
Time 1: Vessel 1 finished berthing.
Time 1: Quay crane starts unloading container 1 from vessel 1.
Time 4: Quay crane finished unloading container 1 from vessel 1.
Time 4: Truck starts transporting container 1 from vessel 1.
Time 4: Quay crane starts unloading container 2 from vessel 1.
Time 7: Quay crane finished unloading container 2 from vessel 1.
Time 7: Quay crane starts unloading container 3 from vessel 1.
Time 7: Truck starts transporting container 2 from vessel 1.
Time 7: Quay crane finished unloading container 2 from vessel 1.
Time 7:Vessel 2 starts berthing.
Time 7: Vessel 2 finished berthing.
.
.
.

的问题在于，正在同时为所有集装箱请求起重机和卡车。这会导致起重机和卡车在它们实际可用之前就被“预订”，从而导致同时操作。

要解决此问题，需要按顺序请求每台起重机和卡车，在卸载一个集装箱并使用卡车将其运走后，再请求下一个集装箱的资源。

修改的 Vessel 类中的 unload 方法，如下所示：

def unload(self):
    """从船只上卸下所有集装箱"""
    for i in range(self.containers):
        # 请求起重机以卸载集装箱
        yield self.env.process(self.unload_container(i))
        # 请求卡车以运输集装箱
        yield self.env.process(self.transport_container(i))

    print(f"Time {self.env.now}: Vessel {self.id} has been fully unloaded and leaves the berth.")

在这个修改后的代码中：

我们循环遍历船只上的每个集装箱。
yield self.env.process(self.unload_container(i)) 行确保在继续下一步之前完成一个集装箱的卸载过程。
卸下集装箱后， yield self.env.process(self.transport_container(i)) 行请求卡车并等待运输完成。

通过这种方式，强制执行以下顺序：

请求起重机
卸载集装箱
请求卡车
运输集装箱
对下一个集装箱重复步骤 1-4

这可以确保一次只使用一台起重机和一台卡车来处理一个集装箱，从而满足的要求。

标签：python,asynchronous,simulation,simpy
From： 78790520

SimPy仿真：集装箱码头如何保证单个集装箱卸货和顺序运输？

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