Lutfi Al-Sharif

University of Jordan | UJ · Department of Mechatronics Engineering

Recent studies have revealed that the dominant traffic pattern of a modern high-rise building is much more complicated than the conventional up-peak model, i.e. incoming traffic only, upon which the popular formula of round trip time (RTT) calculation is based. RTT calculation is still recommended by ISO 8100:32:2020 and CIBSE Guide D: 2020 to prec...

The braking system in an escalator is the most critical safety component. Failure of the escalator braking system can lead to passenger injury and even fatalities. Escalator braking systems can fail in two modes: In the first mode of failure, the braking system fails to arrest the descending load and slow it down when it is not correctly adjusted o...

Elevators are the main means of vertical transportation in buildings and are critical to the success of high-rise buildings today. The most widely used type of elevator is the roped traction elevator. There are a number of different disciplines involved in the design, manufacture, installation, and analysis of building transportation systems. Eleva...

The origin-destination matrix is a two-dimensional matrix that describes the probability of a passenger travelling from one floor in the building to another. It is a two-dimensional square matrix. The row index denotes the origin floor and the column index denotes the destination floor for the passenger journey. A previous chapter described the met...

The Monte Carlo Simulation method (MCS) has been successfully used to find the value of the elevator round trip time under general traffic conditions. It has also been extended to find the value of the round-trip time under destination group control. This paper extends the application of the method by introducing the so-called "interlinked Monte Ca...

A number of different approaches have been used in order to calculate the energy consumption of elevators. Such approaches have ranged from simple rules of thumb, to lookup tables, more detailed equation-based models and simulation-based models. This paper presents an approach based on the use of MATLAB/Simulink to model the various components used...

This is a Simulink based elevator energy simulation model.

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...

The Monte Carlo simulation method has been successfully applied in elevator traffic engineering in a number of areas such as calculating the value of the round trip time under conventional group control and under destination group control, to find the value of the average travelling time, to evaluate the effect of sectoring on the boost in handling...

The Monte Carlo Simulation (MCS) method has been successfully applied in lift traffic systems to evaluate a number of different parameters such as the round-trip time and the average travelling time; and under different conditions, such as sectoring control and for multiple lift cars running in the same shaft. Using the Monte Carlo Simulation metho...

Elevators offer an ideal final year engineering capstone course, due to the multidisciplinary nature of its potential content. This paper sets out to develop a template for planning and delivering such a course at undergraduate engineering level based on experience gained at the School of Engineering at the University of Jordan. There are basically...

Arrival rate is the number of passengers arriving for elevator service in a certain period of time. Arrival rate is fundamental in expressing the heaviness of the traffic. Hence, it is vital for determining the required number of elevators and the specifications of each elevator such as the speed, capacity, and sector sizes. The passenger arrival p...

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...

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 p...

Escalators are known to run unloaded for lengthy periods of time. This results in a very poor running power factor. This paper models and evaluates the benefits of controlling a public service escalator using an optimal power factor controller. A MATLAB/Simulink based SimPowerSystems model is used to model the escalator mechanical load, the inducti...

Lift traffic calculations for planning purposes typically use formulae, or simulation software which applies a traffic control system to dispatch lifts. Formulae methods rely on simplifying the modelling exercise so that the operation of the lifts can be described in mathematical equations. These equations are transparent and repeatable. Simulation...

The escalator braking system is the most important safety components. It is thus necessary to ensure that brakes are tested at regular intervals in order to ensure passenger safety. Carrying out this test using weights is a very complex, risky and expensive procedure, and thus cannot be carried out regularly. For this reason, a model for weightless...

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 incomin...

Planning the kinematics of the journey in mechatronic systems is very critical for the success of these systems. In the majority of cases this involves planning the velocity against time. However, in some cases, the planning is based on displacement against time. The use of a single quintic polynomial for displacement as used in robotic manipulator...

This paper compiles the set of equations required to plot the full set of curves for displacement, velocity, acceleration and jerk for the five possible cases in elevator kinematics. It also lists the MATLAB code for generating the curves for the four variables as a function of time.

The origin-destination matrix is a two-dimensional matrix that describes the probability of a passenger travelling from one floor in the building to another. It is a two-dimensional square matrix. The row index denotes the origin floor for the passenger journey and the row index denotes the destination floor for the passenger journey. The sum of al...

Variable frequency drives are widely used nowadays in all industrial and domestic applications. It is ideal for changing the speed of induction motors by changing the frequency. When the frequency is changed, it is also necessary to change the voltage, in order to prevent the motor from drawing excessive currents and saturating its core. As a rule...

The purpose of this paper is twofold: To introduce a novel method of teaching elevator traffic engineering and associated programming to engineering students; and to analyse the code used to find the value of the elevator round trip time by the Monte Carlo simulation method. The Monte Carlo simulation method is one of the most successful methods fo...

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 elev...

This article discusses the elevator traffic design for high rise buildings. It starts by listing the factors that distinguish high rise buildings from low rise buildings in terms of traffic design as well as the technologies required to address the problems arising from the high rated speeds necessary for high rise buildings. The terms sector, zone...

This article discusses the elevator traffic design for high rise buildings. It starts by listing the factors that distinguish high rise buildings from low rise buildings in terms of traffic design as well as the technologies required to address the problems arising from the high rated speeds necessary for high rise buildings. The terms sector, zone...

One of the sources of efficiency in the operation of double deck elevators is the simultaneous transfer of passengers into and out of the elevator cars, thus leading to a reduction in the value of the round trip time, and thus an increase in the handling capacity. However, due to the randomness of passenger destination selections, this reduction is...

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 commissioning and periodic testing of escalator braking systems still relies on the use of weights placed on the escalator steps. The loaded escalator is run in the down direction at the rated speed and the braking system is applied and the stopping distance measured. The pass/fail criterion is based on comparing the stopping distances to those...

It is generally accepted that passenger arrivals for lift service follow a Poisson arrival process. Moreover, recent research has also shown that the arrivals take place in batches rather than single passenger arrivals. For these reasons, lift traffic simulation software may use the Poisson batch arrival process to generate the time of each batch a...

This paper provides a general set of guidelines on the planning of elevator installations in buildings. It provides a set of guidelines on the dimensional aspects in buildings in order to ensure that the optimal space is used within the building to fit the elevator installations and its means of access. It also provides guidelines on the selection...

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 effectiv...

The right hand rule is used to find the direction of the magnetic field strength that results from a current flowing in a conductor. It cannot however be used to find the polarity of the induced emf from a time varying magnetic flux, in which case Lenz’s law must be used.

Mechanical drive systems are widely used in mechatronic applications in order to convert from rotational motion to translational motion and in order to match speed and torque. Seven examples of such mechanical drive systems are given in this technical note. Mechanical drive systems however, suffer from a number of disadvantages such as wear, energy...

The previous three articles in this series of articles discussed a new paradigm for assessing the performance of up-peak group control algorithms under destination group control. This paper extends this analysis by examining the performance of the algorithms when the destinations of the passengers are revealed one passenger at a time and the contro...

The document contains feedback from nine industry experts on the design of elevator traffic systems for high rise buildings.

The boost in the handling capacity of destination elevator group control systems has been previously calculated under idealised conditions, assuming simultaneously minimum values of the highest reversal floor and of the average number of stops in a round trip. The boost has also been calculated under conditions of allocating the landing calls with...

The boost in the handling capacity of destination elevator group control systems has been previously calculated under idealised conditions, assuming simultaneously minimum values of the highest reversal floor and of the average number of stops in a round trip. The boost has also been calculated under conditions of allocating the landing calls with...

Braking systems are necessary for the correct and safe operation of mechatronic systems. Most functional braking is achieved using electrical braking, which is made possible by the addition of a variable speed drive system (e.g., variable frequency drive system). Electrical braking is efficient and ensures smooth operation and allows the designer t...

One of the important design aspects of any electro-mechanical system or mechatronic system is the selection and design of the controller algorithm. This technical note presents a systematic methodology for the design of the controller algorithm for a system. It assumes some basic knowledge by the reader in the area of system dynamics and classical...

A previous paper introduced the concept of an idealised optimal benchmark (IOB) in order to assess the upper limit on the performance of destination elevator group control systems. Idealised optimal benchmarks are performance parameters evaluated under ideal conditions and with the assumption of perfect knowledge of future passenger destinations. T...

It is assumed that the failure process of a system is best modelled by a Poisson arrival process. In this note, the link is explicitly made between the availability and reliability of a system using the Mean Time Between Failures (MTBF). It is also emphasized that any stated value of reliability of a system must clearly specify the period of time o...

When a cylinder is rotating and translating at the same time, it has an effective mass that is larger than its nominal mass. This technical note derives a formula for the effective mass when subjected to a horizontal force acting through its centre-line and shows that the effective mass is 1.5 times the actual mass of the cylinder.

Double-deck elevators are a very efficient mode of transport, especially in high rise buildings. This is due to the fact that they reduce the number of stops in a round trip (leading to a smaller value of the round trip time hence a higher handling capacity) and take up less space of the core of the building leading to high space usage efficiency....

Since the advent of variable speed drives, they have become widely used in all industrial and residential applications. This short technical note lists the benefits and motivations for the use of variable speed drives. The eight benefits are: energy saving, precise control, passenger comfort, reduced starting currents, less reliance on mechanical b...

This technical note discusses the rationale for using flywheels and in mechanical systems, derives the formula for finding the inertia (second moment of mass) of a flywheel starting from first principles and then discusses a number of relevant applications.

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 chapter explores the concept of an IOB in the area of elevator traffic analysis. It shows that the classical method of...

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, the paper...

This chapter presents a new paradigm for assessing the effectiveness of up-peak elevator group control algorithms. The new paradigm can be very effective in providing a mechanism for objectively assessing and comparing elevator group control algorithms. It is built around three essential components: Idealised optimal benchmarks (IOB); Random Scenar...

This paper presents a new paradigm for assessing the effectiveness of up-peak elevator group control algorithms. The new paradigm can be very effective in providing a mechanism for objectively assessing and comparing elevator group control algorithms. It is built around three essential components: idealised optimal benchmarks; random scenario testi...

This paper presents a methodology for generating the origin-destination matrix from the user requirements specification under general traffic conditions. The user requirements describing the traffic conditions can be specified by the user, expressed as the percentage arrival rate (AR%), the mix of incoming traffic, outgoing traffic and inter-floor...

A previous paper has discussed the concept of two dimensional elevator systems. Two dimensional elevator traffic systems consist of multiple elevator cars travelling in the same shaft both vertically and horizontally. The preference is usually to have unidirectional shafts in order to reduce conflict/obstruction between the different elevator cars...

This paper presents a methodology for generating the origin-destination matrix from the user requirements specification under general traffic conditions. The user requirements describing the traffic conditions can be specified by the user, expressed as the percentage arrival rate (AR%), the mix of incoming traffic, outgoing traffic and inter-floor...

This article provides a general overview of the principles of elevator group control. It lists the variables that are necessary to allow the group controller to make the right decision for the allocation of landing calls to the elevators in the group. It discusses the different types of elevator group algorithms, and the special case of bunching.

The design of vertical transportation systems still relies on the evaluation of the round trip of the elevators during the up peak (incoming) traffic conditions in a building. The evaluation of the round trip time for anything other than the most straightforward case becomes very complicated and requires the use of advanced special condition formul...

It is generally accepted that passenger arrivals for lift service follow a Poisson arrival process. Moreover, recent research has also shown that the arrivals take place in batches rather than single passenger arrivals. For these reasons, lift traffic simulation software may use the Poisson batch arrival process to generate the time of each batch a...

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...

A previous paper introduced the concept of the HARint Plane, which is a tool to visualise the optimality of an elevator design. This paper extends the concept of the HARint plane to the HARint Space where the complete set of user requirements is used to implement a compliant elevator traffic design. In the HARint Space, the full set of user require...

The efficiency of induction motor drives operating under variable conditions can be improved by predicting the optimum flux that minimizes the losses. In this study, a Loss-Minimization Controller (LMC) and a Search Controller (SC) are combined. The output from the controllers would drive the field oriented control inverter in order to achieve the...

The design of an elevator system heavily relies on the calculation of the round trip time under up peak (incoming) traffic conditions. The round trip time can either be calculated analytically or by the use of Monte Carlo simulation. However, the calculation of the round trip time is only part of the design methodology. This article presents a step...

The efficiency of induction motor drives operating under variable conditions can be improved by predicting the optimum flux that minimizes the losses. In this study, a Loss-Minimization Controller (LMC) and a Search Controller (SC) are combined. The output from the controllers would drive the field oriented control inverter in order to achieve the...

Conventional traffic analysis and design methods have traditionally used the interval as the basis for assessing elevator system performance. The use of the interval has a number of limitations. It can only be used with conventional group control systems, and become meaningless with hall call allocation systems (destination control systems). It con...

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...

Part I of this series of articles introduced the general concept of demand [1]. Parts II, IV and V of this series of articles ([2], [4] and [5]) have introduced the concept of the round trip time and different methods for calculating it. Calculating the round trip time is the building block of elevator traffic analysis and design. Rather than being...

The previous article in this series of articles dealt with the four special cases for the round trip time. It developed special equations to deal with each of the special cases under up peak traffic conditions, namely: • Top speed not attained in one floor journey. • Unequal floor heights. • Batch passenger arrivals. • Multiple entrances. The cas...

Project based learning has long been recognised as an effective tool to develop the technical and communication skills of engineering under-graduates. This paper will examine in detail the method of delivery of project based learning within the specialist engineering modules in the degree engineering curriculum. It specifically examines the followi...

When the simplest form of round trip time was derived in Part II of these series of articles, a number of assumptions were made to simplify the derivation. In this article, four of these assumptions are examined and the equations are modified in order to deal with the special case resulting from each of these conditions. Specifically, this article...

The idea of multicar operation within one hoistway is not new. Two-car systems are currently available on the market, whereby the two cars travel with restricted independence because one car must always remain above the other. With recent advances in linear machines, systems with more than two cars in one hoistway will soon become possible. In this...

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 el...

Traffic analysis is one of the three key areas associated with the study of elevator systems, along with the other two areas of drives and of safety components. Elevator traffic analysis is fundamental to the planning and design of elevator systems. Over the years, different approaches have emerged, and they can be broadly classified into analytica...

A previous paper introduced the concept of the HARint plane, which is a tool to visualise the optimality of an elevator design. This paper extends the concept of the HARint plane to the HARint Space where the complete set of user requirements is used to implement a compliant elevator traffic design. In the HARint Space, the full set of user require...

The round trip time is the basis for designing elevator systems. This paper derives the formulae necessary to build the transition probability matrix for the elevator during a round trip under incoming traffic conditions and multiple entrances. A numerical example is then solved by finding the round trip time using the Markov Chain Monte Carlo meth...

The evaluation of the elevator round trip time has been, and still is, fundamental to the design of elevator systems. Historically, the round trip time has been evaluated using analytical methods based on equations. The equations are derived using the expected value of critical parameters that constitute the round trip time. Recently, numerical and...

The first part of this series of articles presented the vertical transportation problem in buildings, which was defined as the design of the elevator system in order to balance the performance of the system against the cost. The second part of this series of articles presented the derivation of the round trip time equation for the most basic of cas...

The first part of this series of articles presented the vertical transportation problem in buildings, which was defined as the design of the elevator system in order to balance the performance of the system against cost. It concentrated on demand by examining the nature of passenger demand in buildings, looking at the magnitude and random nature of...

It has been long known that the elevator traffic system can be modelled as a multi-server queuing system. Each elevator can be represented as a server. The aim of this paper is to analyse the queue lengths and the average waiting times for elevator traffic systems using queuing theory. A discrete event simulation queuing theory model for an elevato...

Elevator group control is critical to the optimal operation of elevator traffic systems under general traffic conditions. In the last 20 years, new elevator group control algorithms have become available for use under up-peak traffic conditions. These up-peak algorithms can be generally classified into three categories: static sectoring, dynamic se...