An integrated framework for elevator traffic design under general traffic conditions using origin destination matrices, virtual interval, and the Monte Carlo simulation method

Abstract

The conventional design methodology for elevator traffic analysis has been applied to the case of up-peak traffic (or incoming traffic conditions). The only user requirements are usually the expected arrival rate ( AR%) expressed as a percentage of the building population requesting service in the peak 5 min and the target interval. The interval as classically used will be referred to as the physical interval in this paper as it is only relevant for the case of a single entrance and incoming traffic conditions. This paper presents an integrated methodology for the design of elevator traffic systems for the general case of mixed traffic conditions. It presents a fully integrated framework that covers the steps from user requirements to the selection of the number of required elevators. The user requirements describing the traffic conditions can be specified by the user, expressed as the AR%, the mix of incoming traffic, outgoing traffic, and interfloor traffic. This paper derives equations that can be used to combine the mix of traffic, the floor arrival percentages, and the floor population percentages into an origin–destination matrix. The origin–destination matrix is then adjusted and normalized in order to account for rational passenger behavior (i.e., a passenger will not travel to the same floor that he or she is at). A method is presented for the random generation of passenger origin–destination pairs using the origin–destination matrix (which is necessary when using the Monte Carlo Simulation ( MCS) method to calculate the round trip time). A novel equation for evaluating the round trip time under the assumption of equal floor heights and top speed attained in one floor journey is derived and used. The equation is derived using a stepwise derivation and verification process. The verification is carried out against the MCS method for finding the value of the round trip time. The concept of a virtual interval (as opposed to the conventionally used physical interval usually used in elevator traffic system design) is introduced in order to allow the selection of the number of elevators to be carried out. The virtual interval is the average value of the time between the consecutive reversals of the elevators in the group. Practical application The methodology presented in this paper allows the elevator traffic system designer to convert the user requirements specification (in the form of an arrival rate and the percentage floor strengths) into an origin–destination matrix. The origin–destination matrix is a more suitable tool for calculating the expected value of the round trip time and consequently carrying out an elevator traffic design. Thus, this methodology represents a vital step in the design process.