Visual servo control with artificial neural network

In this paper a robotic manipulator system is presented, which uses visual feedback to control both the position and orientation of the manipulator. In this system, visual data from the camera are directly used in the servo control process of the manipulator, without calculations of the inverse kinematics. This approach is achieved by the use of an artificial neural network (ANN) to learn the relationship between the position and the orientation of the manipulator and the joint angles. As there are no pre-stored parameters of the manipulator, the system is adaptable to slight changes in the kinematics of the manipulator or the working environment. Hence, this technique should able to extend the application of robotic technology in some special industrial areas. The results of computer simulations of this system are also presented in the paper.published_or_final_versio

Switching transients in electrical installations of buildings in Hong Kong

More and more sensitive electronic and computer-based devices or systems are connected to the electrical installations of buildings. Measures to ensure high power quality in the electricity supply network for the satisfactory operation of such equipment is a hot topic of research in electrical engineering. Electrical transients are one of the important issues in power quality. This paper presents the approach and ideas of a project at the University of Hong Kong which addresses this problem with particular emphasis on switching transients in typical electrical installations in Hong Kong buildings.published_or_final_versio

A novel induction machine design suitable for inverter-driven variable speed systems

Induction machines designed for inverter-driven variable speed systems are different from those fed directly from a utility power line. In this paper, a novel design approach for inverter driven induction machines is presented and implemented. This is followed by an investigation on sizing equations and rotor slot shape specifically for this purpose. The proposed approach permits the integration of the design of machines with inverters, comprehensive performance analysis, and system optimization, resulting in 20-30% higher power density for the induction machine than those designed for direct utility power supplies by conventional methods. Simulation analysis and experimental results are presented to substantiate the conclusions.published_or_final_versio

Intelligent integration of BIPV and load management systems for modern buildings

This paper outlines the basics of load management, and highlights the possibility of maximising the contribution from the Building Integrated Photovoltaic (BIPV) power generation. It will also explain the underlying principles of a dynamic modelling approach and its application in supporting the anticipatory control strategy for load shifting. For many types of building applications, the load profiles are well matched with the BIPV generation profiles such that the BIPV power source is already acting as the peak clipping device. The application of Building Management Systems (BMS) in load shifting should consider the supply from BIPV system. Secondly, due to the thermal mass of the building, there exists time delay in the response of the power requirement of the HVAC system in the building from the solar radiation data. The BIPV system, on the contrary, is responding almost instantaneously to the solar irradiance. A dynamic BIPV model could be applied in aiding the prediction of the load profile. This paper will outline these aspects of the BIPV system as a demonstration of its application in BMS.postprintThe 8th Annual Power Symposium, Hong Kong, 19 June 2009

Integration of BIPV systems and load management

This paper outlines the basics of load management, and highlights the possibility of maximising the contribution from the Building Integrated Photovoltaic (BIPV) power generation. It will also explain the underlying principles of a dynamic modelling approach and its application in supporting the anticipatory control strategy for load shifting. For many types of building applications, the load profiles are well matched with the BIPV generation profiles such that the BIPV power source is already acting as the peak clipping device. The application of Building Management Systems (BMS) in load shifting should consider the supply from BIPV system. Secondly, due to the thermal mass of the building, there exists time delay in the response of the power requirement of the HVAC system in the building from the solar radiation data. The BIPV system, on the contrary, is responding almost instantaneously to the solar irradiance. A dynamic BIPV model could be applied in aiding the prediction of the load profile. This paper will outline these aspects of the dynamic model developed as a demonstration of its application.postprintThe International Conference on Electrical Engineering 2009

Adaptive neuro-fuzzy modeling of battery residual capacity for electric vehicles

This paper proposes and implements a new method for the estimation of the battery residual capacity (BRC) for electric vehicles (EVs). The key of the proposed method is to model the EV battery by using the adaptive neuro-fuzzy inference system. Different operating profiles of the EV battery are investigated, including the constant current discharge and the random current discharge as well as the standard EV driving cycles in Europe, the U.S., and Japan. The estimated BRCs are directly compared with the actual BRCs, verifying the accuracy and effectiveness of the proposed modeling method. Moreover, this method can be easily implemented by a low-cost microcontroller and can readily be extended to the estimation of the BRC for other types of EV batteries.published_or_final_versio

Impact of inflow boundary conditions on the calculation of CT-based FFR

Background: Calculation of fractional flow reserve (FFR) using computed tomography (CT)-based 3D anatomical models and computational fluid dynamics (CFD) has become a common method to non-invasively assess the functional severity of atherosclerotic narrowing in coronary arteries. We examined the impact of various inflow boundary conditions on computation of FFR to shed light on the requirements for inflow boundary conditions to ensure model representation. Methods: Three-dimensional anatomical models of coronary arteries for four patients with mild to severe stenosis were reconstructed from CT images. FFR and its commonly-used alternatives were derived using the models and CFD. A combination of four types of inflow boundary conditions (BC) was employed: pulsatile, steady, patient-specific and population average. Results: The maximum difference of FFR between pulsatile and steady inflow conditions was 0.02 (2.4%), approximately at a level similar to a reported uncertainty level of clinical FFR measurement (3-4%). The flow with steady BC appeared to represent well the diastolic phase of pulsatile flow, where FFR is measured. Though the difference between patient-specific and population average BCs affected the flow more, the maximum discrepancy of FFR was 0.07 (8.3%), despite the patient-specific inflow of one patient being nearly twice as the population average. Conclusions: In the patients investigated, the type of inflow boundary condition, especially flow pulsatility, does not have a significant impact on computed FFRs in narrowed coronary arteries

Intermittent nature of PV system: the applications of dynamic modelling in smart grid

Session A8: paper no. ICEE-A484The Conference programme's website is located at http://www.hkie.org.hk/icee2011/docs/Detailed%20Programme.pdfThe intermittent property of Photovoltaic (PV) system requires some sort of energy storage or supplement to supply the similarly intermittent load demand. This can be achieved by connecting the PV system to the utility grid or to some means of energy storage. When large scale PV systems are connected to the utility grid, it might affect the electrical network stability if not designed properly. An accurate model for forecasting the PV system output would therefore be useful in enhancing the system stability and reliability. This is crucial to the rapidly developing technologies and integrated sources in the smart grid application. This paper will firstly outline the different approaches to model PV system, and try to account for their pros and cons in modelling. Then it will highlight the importance of development of a dynamic model, followed by the methodology in building up the dynamic model. The utilization of the dynamic model for PV systems in smart grid application will be illustrated

A new battery available capacity indicator for electric vehicles using neural network

The ability to calculate the battery available capacity (BAC) for electric vehicles (EVs) is very important. Knowing the BAC and, thus, the driving range cannot only prevent EVs from being stranding on the road but also optimize the utilization of the battery energy storage in EVs. In order to determine the BAC, this paper presents a new neural network (NN) model of the lead-acid battery, based on the battery discharge current and temperature. Comparisons between the calculated BAC from the NN model and the measured BAC from experiments show good agreement. Furthermore, this new approach can readily be extended to the calculation of the BAC for other types of batteries. © 2002 Elsevier Science Ltd. All rights reserved.link_to_subscribed_fulltex

Estimation of battery available capacity under variable discharge currents

In this paper, a new mathematical model in semi-empirical form for lead-acid batteries is presented, which describes the relationship between the battery terminal voltage and the variable discharge current. Based on the proposed model, a new estimation method of the battery available capacity (BAC) in the presence of variable discharge currents is developed. The method involves the real-time identification of the model parameters which are then used to estimate the BAC according to the predefined cutoff voltage and the trend of battery terminal voltage during discharging. Thus, both temperature and aging influences on the BAC are considered inherently. Comparisons between the calculated results and the measured data confirm that the proposed method can provide an accurate real-time estimation of the BAC under variable discharge currents. © 2002 Elsevier Science B.V. All rights reserved.link_to_subscribed_fulltex