Design and implementation of a linear motor for multi-car elevators

The multi-car elevator system is a revolutionary new technology for high-rise buildings, promising outstanding economic benefits, but also requiring new technology for propulsion, safety and control. In this paper we report on experimental results with new components for linear motor driven multi-car elevators. We show that linear synchronous motors with optimized design and with our new safety and control system can be considered as core components of a new generation of elevator systems. The main new results concern the development of a safety system integrated into the propulsion system, the design methodology of a linear motor optimized for the multi-car elevator task, and the motion control system that is expected to be usable for extra high-rise buildings

Linear motor for multi-car elevators, design and position measurement

Multi-car elevator is an emerging technology consisting of two or more elevator cars moving independently in an elevator hoistway, which has become more appealing as building heights increase. In this paper, the design and drive methodologies for a linear motor driven multi-car elevator system with independently moving cars is introduced together with experimental results. Additionally, a safety method developed for the linear motor elevator and the conditions necessary for its proper operation are discussed. The new results introduced in this paper are in the areas of the design method of the linear motor for multi-car elevator system, and the preliminary results for the position measurement system

Cable-Driven Actuation for Highly Dynamic Robotic Systems

This paper presents design and experimental evaluations of an articulated robotic limb called Capler-Leg. The key element of Capler-Leg is its single-stage cable-pulley transmission combined with a high-gap radius motor. Our cable-pulley system is designed to be as light-weight as possible and to additionally serve as the primary cooling element, thus significantly increasing the power density and efficiency of the overall system. The total weight of active elements on the leg, i.e. the stators and the rotors, contribute more than 60% of the total leg weight, which is an order of magnitude higher than most existing robots. The resulting robotic leg has low inertia, high torque transparency, low manufacturing cost, no backlash, and a low number of parts. Capler-Leg system itself, serves as an experimental setup for evaluating the proposed cable- pulley design in terms of robustness and efficiency. A continuous jump experiment shows a remarkable 96.5 % recuperation rate, measured at the battery output. This means that almost all the mechanical energy output used during push-off returned back to the battery during touch-down

Industrial applications of the Kalman filter:a review

International audienc

Machine learning solutions for maintenance of power plants

The primary goal of this work is to present analysis of current market for predictive maintenance software solutions applicable to a generic coal/gas-fired thermal power plant, as well as to present a brief discussion on the related developments of the near future. This type of solutions is in essence an advanced condition monitoring technique, that is used to continuously monitor entire plants and detect sensor reading deviations via correlative calculations. This approach allows for malfunction forecasting well in advance to a malfunction itself and any possible unforeseen consequences. Predictive maintenance software solutions employ primitive artificial intelligence in the form of machine learning (ML) algorithms to provide early detection of signal deviation. Before analyzing existing ML based solutions, structure and theory behind the processes of coal/gas driven power plants is going to be discussed to emphasize the necessity of predictive maintenance for optimal and reliable operation. Subjects to be discussed are: basic theory (thermodynamics and electrodynamics), primary machinery types, automation systems and data transmission, typical faults and condition monitoring techniques that are also often used in tandem with ML. Additionally, the basic theory on the main machine learning techniques related to malfunction prediction is going to be briefly presented

A Thermal Analysis of Direct Driven Hydraulics

This paper focuses on thermal analysis of a direct driven hydraulic setup (DDH). DDH combines the benefits of electric with hydraulic technology in compact package with high power density, high performance and good controllability. DDH enables for reduction of parasitic losses for better fuel efficiency and lower operating costs. This one-piece housing design delivers system simplicity and lowers both installation and maintenance costs. Advantages of the presented architecture are the reduced hydraulic tubing and the amount of potential leakage points. The prediction of the thermal behavior and its management represents an open challenge for the system as temperature is a determinant parameter in terms of performance, lifespan and safety. Therefore, the electro-hydraulic model of a DDH involving a variable motor speed, fixed-displacement internal gear pump/motors was developed at system level for thermal analysis. In addition, a generic model was proposed for the electric machine, energy losses dependent on velocity, torque and temperature was validated by measurements under various operative conditions. Results of model investigation predict ricing of temperature during lifting cycle, and flattened during lowering in pimp/motor. Conclusions are drawn concerning the DDH thermal behavior

Methods of condition monitoring and fault detection for electrical machines

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Development and Application of Two New Brushless Reluctance Motor Drives

The switched reluctance (SR) motor is a new form of brushless DC motor without permanent magnets, capable of low cost manufacture and a wide speed range. Because of its simplicity, ruggedness and wide speed range, it is a candidate for a broad range of applications from domestic appliances to aerospace and automotive actuators. In this thesis, two original aspects of the SR motor drive are explored. First, the application of the SR motor to a domestic food processor is explored by designing, building and testing two prototype drives. This project provided experience on the entire system design. In particular, it permitted an evaluation of the SR drive at high speed with respect to its efficiency, thermal characteristics, power density and noise level in comparison with a conventional AC series commutator motor with triac control. The second aspect of this thesis is an original investigation into the use of flux screens to improve the specific torque (torque per unit volume) of 'the switched reluctance motor. The torque of the SR motor is determined by the variation of self-inductance of the phase windings as the rotor rotates. Under dynamic operating conditions this variation can, in principle, be increased by dynamically decreasing the minimum selfinductance through the use of eddy current screens. Several configurations of screens are postulated, analyzed by finite-element techniques and tested in an experimental motor. Although the experimental results are inconclusive, this investigation introduces some interesting possibilities for future motors. The work described in this thesis was entirely sponsored by industry, and particular acknowledgement is made to Kenwood Ltd. (food processor project); Lucas (disk motor project); and the SPEED consortium (flux screen project)

Comparative study and selection criteria of linear motors

Initially, linear motors have been particularly dedicated to transportation systems. Nowadays, linear motors are meant to replace a system using a rotating motor and a transmission to realize a linear movement. With linear motors the performances increase considerably since the mechanical limitations are removed. This leads to a better precision, a higher acceleration and a higher speed of the moving part. Therefore, direct drives with linear motors are increasingly used in industrial applications although these solutions need often more investment costs. Different linear motor structures and technologies exist. They can be either induction or synchronous motors with a transverse or a longitudinal flux. Furthermore, linear motors may have several topologies. They can be either long or short stator and double or single sided. All these variants may be combined giving therefore numerous possibilities to perform a linear movement. Hence, to make the best choice for a given application, a global methodology based on the comparison of optimized motors is presented in the thesis. This design methodology is based on figure of merits which are bound to the specifications of the studied application. This method differs from a conventional one since optimized motors with the same objective function are compared. The optimized motors are obtained by an indirect method based on an optimization algorithm (Sequential Quadratic Programming, SQP). An indirect approach differs from the conventional deterministic one for which at least one parameter must be fixed to obtain a motor pre design, since there are constraints and validity domain which are introduced. The proposed methodology can be applied either to rotating or to linear motor design. The use of an optimization program to perform motor designs requires analytical motor models. The models developed in this thesis take into account the thermal behavior of the motors in order to achieve more realistic results. Furthermore, the analytical models of synchronous motors are thoroughly studied leading to several interesting conclusions. They are based on well known algorithms developed for rotating motors. The proposed models are very accurate in comparison with the FEM program, except for a transversal flux linear motor for which the obtained results are not worthwhile enough to be optimized. This is caused by the structure of the motor which is close to a reluctant motor and imposes to model the motor by a lumped magnetic scheme. Moreover, a global analysis of the windings due to the particularity of linear motor to have an even or odd number of poles is presented in the thesis. The methodology proposed in the thesis is successfully used for an innovative application which deals with a multi mobile system for a lift. For this lift, several cabins travel in the same shaft implying linear motors to move autonomously each cabin. First, by comparing the different motor technologies, the best motor type is selected. Afterwards, the motor windings for the selected motors are analyzed and compared in order to find the most adapted one for this application. The motor is finally optimized, leading to a motor design proposal. This motor design takes into account the thermal behavior, the material cost and the electrical characteristic of the linear motor

Product development approach for a stabilized ambulance stretcher

The level of vibrations that a patient experiences during ambulance transport is often too high. The ambulance crew must take measures to reduce the effects of vibration. Currently, they do it by reducing the speed at which the ambulance transports the patients or by deviating from the shortest routes to routes that have better conditions for transport. The deviation in the route is required to avoid speed bumps, potholes and other obstacles that cause high vibration peaks. These vibrations are most severe in the vertical direction. The human body is most sensitive to vibrations in the range from 0.1 to 80 Hz, and it is within this range that the dominant vertical vibrations of an ambulance stretcher occur. The vibrations experienced can be reduced by placing an active stabilization unit in between the stretcher mattress and the legs of the stretcher. This active system performs vibration compensation in real time. The system is controlled with a data logger which collects the vibrational information from the road and transfers that data to the control system. The system is based on a spring-motor configuration. The springbased systems help to keep the mattress in position thereby reducing the effects of vibration and improving the comforts of patient transport. Since the stabilization unit increases the weight of the stretcher, currently this device cannot be employed for nonpowered stretchers. A business plan for the product launch is analyzed. The business plan provides the information to make this product market ready. A financial analysis is also performed to support the claims of the business plan. The business plan is focused on launching the stabilization device and then provides insight into developing stretcher solutions for the market.O nível de vibrações que um paciente experimenta durante o transporte de ambulância é muitas vezes demasiado elevado. O pessoal da ambulância tem que tomar medidas para reduzir os efeitos da vibração. Atualmente isso é feito reduzindo-se a velocidade com que a ambulância transporta os pacientes ou desviando-se das rotas mais curtas para as rotas que têm melhores condições de transporte. O desvio na rota precisa ser feito para evitar lombas, buracos e outros obstáculos que causam altos picos de vibração. Essas vibrações são mais severas na direção vertical. O corpo humano é mais sensível a vibrações na faixa de 0,1 a 80 Hz, e é dentro dessa faixa que ocorrem as vibrações verticais dominantes numa maca de ambulância. As vibrações no transporte de pacientes podem ser reduzidas colocando uma unidade de estabilização ativa entre o colchão da maca e a estrutura da maca. Este sistema ativo realiza a compensação de vibração em tempo real. O sistema é controlado por um processador de dados que coleta informações vibracionais da estrada e transfere esses dados para o sistema de controlo. O sistema atua através de uma solução dinâmica com um motor passo a passo. Os sistemas baseados em motores passo a passo ajudam a manter o colchão em posição, reduzindo assim os efeitos da vibração e melhorando o conforto do transporte do paciente. Como a unidade de estabilização aumenta o peso da maca, atualmente este dispositivo não pode ser empregado para macas não motorizadas. Com base na proposta de produto concebido, um plano de negócios para o lançamento do produto desenhado. O plano de negócios fornece as informações para preparar o lançamento deste novo produto no mercado. Também foi realizada uma análise financeira para validar os pressupostos do plano de negócios. O plano de negócios foi construído com o foco no lançamento do dispositivo de estabilização e, em seguida, pressupõem extensões assentes no posterior para o desenvolvimento de soluções de maca integral a colocar no mercado