Multivisit Drone-Vehicle Routing Problem with Simultaneous Pickup and Delivery considering No-Fly Zones

Table 2

Model symbols and explanations.

Notation	Description
Parameters
	Farthest flying distance of a drone
	A large positive integer
	Self-weight of drones
	Demand of customer
	Recycling volume of customer
	Maximum loading capacity of trucks/drones
	Unit transportation cost of trucks/drones
	Distance between truck/drone from node to node
Variables
	Truck passes through arc
	Drone trip carried on truck passing through arc
	Customer is served by truck
	Customer is served by drone trip carried on truck
	Customer is the launch node of drone trip carried on truck
	Customer is the retrieved node of drone trip carried on truck
	Customer is in the no-fly zones
	Load of truck when it leaves the depot
	Loading capacity of truck/drone after service to customer
	Truck/drone access sequence for node