Elevator Traffic System Research Articles

Optimization of energy consumption in vertical mobility systems of high-rise office buildings: A case study from a developing economy

Elevator systems serve as the primary mode of transportation in tall buildings which consumes approximately 5–15% of a building's total energy demand. This research explores the potential for energy savings in elevator systems while maintaining passenger comfort through the implementation of green approaches. The research concentrates on a contemporary high-rise office building situated in the central business district of a developing economy. It employs a case study methodology involving traffic simulation to determine optimal elevator specifications for industry-standard service levels. By conducting the simulation, the researchers identified the optimal number of elevators, elevator capacity, speed, and the most suitable elevator management system. Following that, a range of green measures were implemented, including the incorporation of a regenerative system, to effectively reduce the electrical energy consumption of the elevator system. Subsequently, a passenger traffic simulation model was integrated with an energy calculation model to jointly simulate and calculate the elevator system's overall energy consumption and regeneration. The elevator energy requirements were optimized, while maintaining user-friendliness and requirements related to guidelines given in the standards. The results showed that 36% of the energy consumption was reduced by incorporating an energy regenerative option into the elevator system in addition to selecting efficient mechanical components and implementing an efficient elevator traffic management system. This research contributes to the limited body of literature on energy optimization in elevators and emphasizes the importance of balancing energy efficiency with service quality. These findings provide guidance for establishing benchmarks in reducing energy consumption, in relation to elevator systems.

Analytical round-trip time estimation of a three-dimensional elevator system based on exact stopping position identification

Two-dimensional (2-D) as well three-dimensional (3-D) elevators are expected to become a vital part of the future building transportation systems. In order to carry out an elevator traffic system design for a 3-D system, it is necessary evaluate the round-trip time. A ‘scanning’ approach has been previously developed to find the value of the round trip time in 2-D and 3-D systems. The 3-D path of scanning could be linearized into a 1-D line as in a conventional elevator system. It was later found that the RTT is insensitive to the exact stopping positions in a 1-D system, but extremely sensitive in a 2-D or 3-D system. Furthermore, in the conventional 1-D traffic analysis, the average number of stops is non-integral because stops are repeatable within trips, causing a great trouble in estimating RTT in a 3-D system. In this article, with the help of order statistics, the method to break down a series of repeatable stops in a 3-D system into several series of non-repeatable stops is described in detail. And the number of stops of all these non-repeatable series becomes integral, making it suitable for analytical calculation. Then, the RTT of each “non-repeatable” series is separately estimated analytically, with the overall RTT with repeatable stops given by the weighted sum of all these “non-repeatable” series. Methods to estimate the average RTT of each non-repeatable series, the probability density function of each series, and the final weighted average are discussed. Finally, the results are verified using the Monte Carlo simulation method. The method described in this article can give designers a much clearer understanding of the overall concept of RTT estimation by calculation in a multi-dimensional system.

Analysis and comparison of the two sectoring approaches in elevator traffic systems

Sectoring is a group control algorithm that is used in elevator traffic control systems by grouping passengers that have common destinations or common origins into elevator cars that serve these floors. The building is split into sectors usually comprising contiguous floors. Two different alternative algorithms for sectoring are discussed in this paper. The first approach is based on dynamic allocation with equal sector allocation. The second approach is based on static allocation with unequal sector sizes. Under static allocation, the same elevator car is allocated to the same sector in every round trip. Under dynamic allocation, each elevator car is allocated to a different sector in each round trip. Under the dynamic allocation scheme suggested in this paper, the elevator cars are sequenced to the various sectors in the buildings in a round-robin fashion. It is important to note that under both schemes, the provided (relative) handling capacity of different sectors is equalised. Five different buildings have been analysed using the two suggested sectoring algorithms. The building is first designed by finding the required number and speed of elevators assuming conventional control. Each building is then analysed using one of the two suggested sectoring algorithms. In order to compare the performance of the two sectoring algorithms, the provided (relative) handling capacity is calculated. The provided (relative) handling capacity of the two suggested algorithms is then compared. Very little difference was found between the two algorithms. The dynamic sectoring with equal sector sizes offers the convenience of having equal sector sizes. The static sectoring with unequal sector sizes is more convenient for passengers that are familiar with the building. Practical application: This paper analyses two different options for sectoring the control system of an elevator system in a building. Each of the two sectoring methods is suitable for different situations. The dynamic allocation method is more suitable for destination group control systems and offers the group controller more flexibility. The static allocation method with unequal sector sizes ensures that the passengers remain familiar with the elevators that they use to get to their floors. The programmer of the elevator group controller can programme both methods in the controller and allow it to switch to the most suitable algorithm depending on the prevailing conditions.

Calculation of the elevator round-trip time under destination group control using offline batch allocations and real-time allocations

The use of Destination Group Control (DGC), or Hall Call Allocation (HCA), in elevator traffic system group control is the current trend in intelligent and advanced supervisory control and expected to dominate the market in the future. In the conventional elevator traffic design process, designers usually start with a simple calculation in order to obtain a conceptual estimate of the suggested design prior to moving onto simulation. But due to the lack of a suitable set of equations for elevator traffic calculation for DGC systems, designers are forced to carry out the elevator traffic design process for a system controlled by DGC solely by using simulation. Due to dependence on the simulator and algorithms it uses, different simulation packages will produce different resultant designs. Thus, the motivation for this paper is to use calculation in order to achieve more transparency and repeatability in the design of DGC systems.In order to enable the designer to carry out a calculation for the DGC system, equations are needed to evaluate the values of H (the highest reversal floor) and S (the expected number of stops in a round trip) in order to evaluate the value of the round-trip time under destination group control. Although equations are available to compute the highest reversal floor, H, and expected number of stops, S, of a DGC system, these equations assume optimal idealized conditions and do not take into consideration the effect of real time allocation of landing calls to elevator cars. If designers use them to design the elevator traffic system, the design will be under-sized and inadequate. They do not take into consideration many of the practical implementation issues and non-ideal conditions such as: unequal floor populations, real time call allocation of calls to elevator cars, and the different floor to sector arrangements, as well as the practicalities of allocating elevator cars to sectors.In this paper, more detailed consideration is given to the estimation of H and S under both offline and real-time call allocations under up-peak traffic conditions. Three methods of sectoring are suggested to take care of different combinations of the number of floors, the number of elevators, the car capacity, and the floor population distribution. Results of this research would help the designer carry out a more reasonable and practical calculation of the round-trip time under DGC and thus arrive at a transparent and repeatable elevator traffic design.The designer is still expected to move on to a simulation phase in order to understand the effect of the group controller on system performance.

Comprehensive analysis of elevator static sectoring control systems using Monte Carlo simulation

For a long time, there was no action that a group controller could take during incoming traffic conditions other than returning the elevators back to the main entrance and opening their doors. Passengers would arrive in the main entrance and board the first available elevator car. However, in the early 1990s, sectoring was introduced during incoming traffic conditions. Sectoring is the soft division of the building into groups of (usually but not necessarily contiguous) floors, usually of equal populations. One or more elevators are assigned to a sector. The allocation of the elevator(s) to a sector can either be fixed (static sectoring) or variable (dynamic sectoring) within consecutive round trips. In addition, the size and composition of the different sectors can be static or dynamic. Sectoring is thus a powerful tool in dealing with peaks of incoming traffic demand. However, most of the analysis carried out to understand the effects of sectoring on the performance of the elevator traffic system has been based on simulation only. This paper presents a comprehensive calculation-based analysis of static sectoring control for incoming traffic as a control tool. The analysis is based on the approach of progressively increasing the number of sectors in a building, starting from a single sector (i.e., no sectoring) and proceeding to full sectoring (where the number of sectors equals the number of elevators in the group) and even increasing the number of sectors up to the total number of floors above the main entrance (which has been given the new term: super-sectoring). An analysis is carried out in each case showing the handling capacity, car loading, average waiting time, and average traveling time. Practical application: This paper allows a control system designer to adapt the actions of the controller to the change in passenger arrivals. The control can detect the intensity of passenger arrivals and adjust the number of sectors to suit such an arrival intensity. The aim would be to maximize the handling capacity of the system or minimize the car loading.

Traffic analysis of a three-dimensional elevator system

This article presents an overview of the concept of a hypothetical three-dimensional elevator system in extra-large buildings. The term three dimensional is used in this context in order to contrast the system with current conventional one-dimensional elevator systems that move bi-directionally in a dedicated vertical shaft; or two-dimensional elevator system that moves in a plane (e.g. in x-horizontal direction and z-vertical direction). The hypothetical three-dimensional elevator system presented in this article assumes that the elevator car can travel in all three directions (but obviously not at the same time). The proposed system comprises a vertical main shaft that allows elevator cars to travel to the required floor, and then to travel in two dimensions in a horizontal plane at the level of the required floor along a network of horizontal shafts in both x- and y- directions. Each elevator car is dispatched to one floor only in each round trip. This is more efficient as it removes the need to visit more than one floor in each journey, but relies heavily on the use of destination group control systems (in order to allow the allocation of the passengers destined to the same floor to the same elevator car). The article presents the general overview of the suggested system using sketches and then derives equations for calculating the round trip time for the elevator car. The Monte Carlo Simulation method is then used to verify the correctness of the derived equations. Practical application: This manuscript provides a high level overview of the possible arrangement of a three-dimensional elevator traffic systems in a very large building. It can be used by architects to explore the possibility of employing a three-dimensional elevator system in a large building and checking its feasibility.

Rule-based calculation and simulation design of elevator traffic systems for high-rise office buildings

Elevator traffic system design has been traditionally based on rules of thumb and the designer’s judgement and expertise. This is especially true for high-rise buildings. This paper attempts to develop a systematic methodology for the design of high-rise buildings, by the use of rational rules. In order to ensure clarity and consistency, it defines the terms sector, zone and stack. A sector is a group of floors that are served by one or more elevators in a journey and are not necessarily fixed and are not necessarily contiguous. A zone is a group of contiguous floors that are served by a group of elevators and are fixed in hardware. When a number of zones are grouped together they form a stack, which is effectively a building within a larger building that is served by a main lobby or by a sky lobby. The systematic methodology is built around the use of rational rules. Rational rules differ from rules of thumbs in a number of ways, and these are discussed in the paper. Six rational rules are presented and used in the design of high-rise buildings. The rules are triggered by the checking of a number of design parameters such as the waiting time and the transit time, as well as the core area used up and the number of elevators in the group. A simulator for incoming traffic and a single entrance is used in order to obtain the parameters for a design and then to trigger the rational rules. Five case studies on the design of various buildings are presented in order to illustrate the use of the six rules. In addition, feedback from the industry experts is reviewed in a dedicated section. Practical application: This paper presents a set of six rules for the design of elevator traffic systems for high-rise buildings. Armed with calculation and simulation tools, the designer can follow the six rules in a systematic procedure in order to arrive at a compliant elevator traffic design for high-rise buildings.

Reconciling the value of the elevator round trip time between calculation and simulation

This paper attempts to understand the reasons for the difference in the value of the round trip time between calculation and simulation. It is posited the main reason for the difference is the combination of two factors: the restricted car capacity and the randomness in the behavior of the elevator traffic system, thus leading to a reduced effective car loading (effectively based on a smaller number of passengers in the car). There are three sources of randomness in the behavior of the system: the randomness of the passenger destinations (thus making the value of the round trip time a random variable), the randomness of the passenger arrival (driven by a Poisson passenger arrival model), and the effect of elevator bunching (thus making the value of the interval a random variable). Using a MATLAB-based simulator, the value of the round trip time is plotted against the system loading level for the case of a single entrance and incoming traffic only. Different conditions are simulated, including constant and random passenger arrivals, as well as queues-allowed and queues-not-allowed conditions. Varying these conditions provides an essential insight into the variation of the round trip time and the reasons for it. The effect of the number of passengers boarding the elevator on the value of the round trip time (and thus on the value of the system handling capacity) is investigated in more detail.

Concept design and derivation of the round trip time for a general two-dimensional elevator traffic system

A two dimensional elevator traffic system that moves on the façade of large buildings is presented in this paper. The building is assumed to have N floors and M rooms on every floor (effectively M vertical shafts), leading to N·M rooms in total. The elevator cars can move freely both horizontally and vertically.In each trip, the elevator car only picks up passengers heading to two of the M vertical shafts, denoted as shafts a and b. Such an arrangement provides three advantages: it reduces the number of stops in a round trip thus reducing the value of the round trip time (increasing the handling capacity); the number of turn-round operations between horizontal and vertical directions are limited to four operations in each round trip (thus saving a lot of time); and it reduces the probability of conflicts between the different cars in the group.The paper discusses the use of a double skin façade as a network of shafts for the two-dimensional elevator system. A detailed set of formulae is then derived for the round trip time and its components. This is followed by a verification example for a large building, whereby the round trip time is evaluated using the derived equations and verified against the values obtained using the Monte Carlo simulation method.The methodology presented could be used in order to size a generic two-dimensional elevator traffic system to meet higher user requirements for the future.

Effect of stopover on motion of two competing elevators in peak traffic

We study the dynamic motion of two competing elevators when elevators stop over at some floors. We present the dynamic model of elevators to take into account the stopover effect. The dynamics of the elevator traffic system is described by a pair of deterministic nonlinear maps. The motion of two elevators is determined by the five parameters: the numbers of stopovers at two elevators, the fraction of passengers choosing the first elevator, the fraction of passengers choosing the second elevator, and the inflow rate. The dynamics of two elevators depends highly on these parameters. The motion of two elevators displays a complex behavior by a neck-and-neck race between two elevators. We explore the dependence of elevator motion on the fractions of two kinds of passengers, the numbers of stopover floors, and the inflow rate.

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

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.

Complex motion induced by elevator choice in peak traffic

We study the dynamic motion of two elevators by an elevator-choice strategy of passengers. An elevator is correlated with another elevator by the elevator choice. The dynamics of the elevator traffic system is described by a pair of deterministic nonlinear maps. The motion of two elevators is determined by the three parameters: the passenger’s preference, the fraction of fast passengers, and the inflow rate. The dynamics of two elevators depends highly on the elevator-choice strategy. The motion of two elevators displays a complex behavior by a neck-and-neck race between two elevators. We explore the dependence of elevator motion on the passenger’s preference, the fraction of fast passengers, and the inflow rate.

Establishing the upper performance limit of destination elevator group control using idealised optimal benchmarks

The concept of an idealised optimal benchmark (IOB) is used in many engineering disciplines. An example of an IOB from the area of thermodynamics is the formula for evaluating the maximum possible efficiency of a heat engine. This paper explores the concept of an IOB in the area of elevator traffic analysis. It shows that the classical method of elevator traffic design by calculating the value of the round trip time is an example of an IOB; it also lists the assumptions that lie behind the formulae to illustrate this. It then extends the concept of an IOB to calculating the maximum performance of an elevator system when destination group control is applied under incoming traffic conditions. Formulae are derived for finding the minimum values of the expected number of stops ( S) and the highest reversal floor ( H) under destination group control during incoming traffic conditions. The assumption is that the L elevators in the group are sequenced (or rotated) to the L virtual sectors in the building, in order to equalise the handling capacities of the L sectors in the group. A numerical example is presented to illustrate the calculation of the maximum possible handling capacity and comparing it to the handling capacity that is achieved under conventional incoming traffic group control. Three numerical algorithms are also used to find the practical minimum values of H and S, the results of which are compared to the IOB using the equations derived above. Practical application: The concept and the accompanying formulae presented in this paper allow the elevator traffic designer to assess the improvement in the handling capacity of the elevator traffic system when he/she changes the group controller from a conventional group controller to a destination group controller. This improvement could be as much as 200%.

Stepwise derivation and verification of a universal elevator round trip time formula for general traffic conditions

The evaluation of the round trip time ( τ) still forms the basis for the design of elevator traffic systems. The elevator round trip time is the time taken for the elevator to complete a full cycle of the building, picking up passengers from their origin floors and dropping them off at their destination floors. It is assumed that the elevator car transports P passengers from their origins to their destinations during one round trip. By dividing the value of the round trip time by the target interval, the required number of elevators in the group can be found and fed into the overall traffic design. Traditionally, simplified formulae have been used to evaluate the value of the round trip time under a number of simplifying assumptions. This paper develops the formulae for the most general case of mixed traffic conditions, whereby every floor can be an occupant floor and an exit/entrance floor (i.e. every floor can have a percentage population, U( i), and a percentage arrival rate, Parr( i)). However, the formulae developed make a simplification by assuming a constant passenger arrival model, rather than the widely accepted Poisson passenger arrival model. The new developed set of formulae comprises three parts: the kinematic part ( τK), the door part ( τS) and the passenger transfer part ( τP). The kinematic part in turn comprises six components: the up journey ( UJ) time; the down journey ( DJ) time; the upper connecting journey ( UCJ) time; the lower connecting journey ( LCJ) time; the down return journey ( DRJ) time; and the up return journey ( URJ) time. The derivation process is accompanied by stepwise verification of all the different components of the round trip time using the Monte Carlo simulation (MCS) method. The results of the formulae match those from the MCS to less than 0.0025%. Practical application: Engineers usually design elevator traffic systems under up-peak traffic conditions, where only incoming traffic is assumed. It is sometimes useful to assess the design under a mixture of traffic conditions (e.g. lunchtime conditions). The formulae developed in this paper can thus be used to allow the designer to evaluate the round trip time under a mixture of traffic conditions. In practice, the formulae would not be evaluated by hand, but implemented as a software programme. Once the designer has evaluated the round trip time under the specified mix of traffic conditions (e.g. 40% incoming traffic; 40% outgoing traffic; 20% inter-floor traffic), then he/she can divide that number by the target interval to find the required number of elevators. This result can then be compared to the required number of elevators under up-peak conditions to assess the adequacy of the design for these mixed traffic conditions.

The Development and Application of VR Simulation System Based on the Elevator Manufacture System

In this thesis, the problem of elevator manufacture system in domestic practice was analyzed. The variables and parameters, which had an impact on the service quality of elevator traffic system directly, were presented detailed comparison and analysis. And then the expressions of these variables and values of parameters were edited, according to the situation of origin country. The computer aided design software was designed. Now, this VR simulation system software has passed the testing, and has also achieved successful application in design of elevator manufacture system.

A Queue Dispatch Optimizing Method for Elevator Traffic System

In this paper, a new method is presented to optimize the elevator traffic system based on queue model. The application of this method is studied in detail. Parameters for the elevator running including number of elevator passenger, average waiting time and arriving ratio, and the relationships between them have been analyzed as well. Therefore, the dispatching of elevator dynamic partition can be done. The actual data of rush hours are used for simulation tests. The simulation results show that this method has good performance. The method is a more practical control strategy especially in rush hours.

Elevator Group Control System Based on Fuzzy Single-Chip Computer

What the group control of the elevator traffic system deal with is a complex, random, multi-objective, nonlinear, uncertain decision-making problem. Good effect of controlling elevators can’t be achieved with traditional control methods. Elevator group control system based on fuzzy single chip computer is introduced in this paper. Fuzzy inference can be carried out based on control rules that are programmed based experts’ experience. Then elevators are allocated in the light of inference result in order to achieve ideal control effect.

The modelling and simulation of elevator group control sytems for public service buildings

Elevator traffic control systems have become more and more complicated due to their nature of intelligence. Artificial intelligence methods employing neural networks have been proved to be successful in many fields, such as process modeling, pattern recognition and classification problems. They have also been applied to basic problems in elevator traffic control systems, such as the prediction and control of elevator movements. In particular, neural networks can offer better solutions to the passenger call allocation process when compared to the classical traffic control methods. Elevator control algorithms utilizing neural networks aims at distributing the most suitable cars to the floors by considering the passenger service demand. Neural networks can dynamically learn the behavior of an elevator system and predict the next floors to stop, based on what has been learnt. In this paper the neural network approach has been applied to Duplex/Triplex group control systems for improving passenger waiting time and a lift simulation software has been developed and implemented in order to assess the learning capability by measuring the performance of the control algorithm. The lift traffic analysis have been carried out by examining the simulation results obtained.