A novel linear direct drive system for textile winding applications

The paper describes the specification, modelling, magnetic design, thermal characteristics and control of a novel, high acceleration (up to 82g) brushless PM linear actuator with Halbach array, for textile package winding applications. Experimental results demonstrate the realisation of the actuator and induced performance advantages afforded to the phase lead, closed-loop position control scheme

A miniature short stroke tubular linear actuator and its control

Miniature actuators are the critical components in the robotic applications with high intelligence, high mobility and small scales. Among various types of actuators, linear actuators show advantages in many aspects. A miniature short stroke PM tubular linear actuator for the micro robotic applications is presented in this paper. The actuator is deliberately designed based on the optimal force capability and a proper sensorless control scheme is developed for the driving of the actuator. Experiment both on the prototype of the actuator and the drive system show the validity of the design

Design and control of a linear electromagnetic actuation system for active vehicle suspensions

Traditionally, automotive suspension designs have been a compromise between the three conflicting criteria of road holding, load carrying and passenger comfort. The Linear Electromagnetic Actuation System (LEA) design presented here offers an active solution with the potential to meet the requirements of all three conditions. Using a tubular permanent magnet brushless AC machine with rare earth magnets, thrust densities of over 6 x 105 N/m3 can be achieved with a power requirement of around 50W RMS, much less than equivalent hydraulic systems. The paper examines the performance of the system for both the quarter car and full vehicle simulation, considering high level control of vehicle ride and chassis roll, with the vehicle model being parameterized for a target Jaguar XJ test vehicle. Results demonstrate the ability for 100% roll cancellation with significant improvements in ride quality over the passive Jaguar system

Generalized harmonic modeling technique for 2D electromagnetic problems : applied to the design of a direct-drive active suspension system

The introduction of permanent magnets has significantly improved the performance and efficiency of advanced actuation systems. The demand for these systems in the industry is increasing and the specifications are becoming more challenging. Accurate and fast modeling of the electromagnetic phenomena is therefore required during the design stage to allow for multi-objective optimization of various topologies. This thesis presents a generalized technique to design and analyze 2D electromagnetic problems based on harmonic modeling. Therefore, the prior art is extended and unified to create a methodology which can be applied to almost any problem in the Cartesian, polar and axisymmetric coordinate system. This generalization allows for the automatic solving of complicated boundary value problems within a very short computation time. This method can be applied to a broad class of classical machines, however, more advanced and complex electromagnetic actuation systems can be designed or analyzed as well. The newly developed framework, based on the generalized harmonic modeling technique, is extensively demonstrated on slotted tubular permanent magnet actuators. As such, numerous tubular topologies, magnetization and winding configurations are analyzed. Additionally, force profiles, emf waveforms and synchronous inductances are accurately predicted. The results are within approximately 5 % of the non-linear finite element analysis including the slotted stator effects. A unique passive damping solution is integrated within the tubular permanent magnet actuator using eddy current damping. This is achieved by inserting conductive rings in the stator slot openings to provide a passive damping force without compromising the tubular actuator’s performance. This novel idea of integrating conductive rings is secured in a patent. A method to calculate the damping ratio due to these conductive rings is presented where the position, velocity and temperature dependencies are shown. The developed framework is applied to the design and optimization of a directdrive electromagnetic active suspension system for passenger cars. This innovative solution is an alternative for currently applied active hydraulic or pneumatic suspension systems for improvement of the comfort and handling of a vehicle. The electromagnetic system provides an improved bandwidth which is typically 20 times higher together with a power consumption which is approximately five times lower. As such, the proposed system eliminates two of the major drawbacks that prevented the widespread commercial breakthrough of active suspension systems. The direct-drive electromagnetic suspension system is composed of a coil spring in parallel with a tubular permanent magnet actuator with integrated eddy current damping. The coil spring supports the sprung mass while the tubular actuator either consumes, by applying direct-drive vertical forces, or regenerates energy. The applied tubular actuator is designed using a non-linear constrained optimization algorithm in combination with the developed analytical framework. This ensured the design with the highest force density together with low power consumption. In case of a power breakdown, the integrated eddy current damping in the slot openings of this tubular actuator, together with the passive coil spring, creates a passive suspension system to guarantee fail-safe operation. To validate the performance of the novel proof-of-concept electromagnetic suspension system, a prototype is constructed and a full-scale quarter car test setup is developed which mimics the vehicle corner of a BMW 530i. Consequently, controllers are designed for the active suspension strut for improvement of either comfort or handling. Finally, the suspension system is installed as a front suspension in a BMW 530i test vehicle. Both the extensive experimental laboratory and on-road tests prove the capability of the novel direct-drive electromagnetic active suspension system. Furthermore, it demonstrates the applicability of the developed modeling technique for design and optimization of electromagnetic actuators and devices

Generalized harmonic modeling technique for 2D electromagnetic problems : applied to the design of a direct-drive active suspension system

The introduction of permanent magnets has significantly improved the performance and efficiency of advanced actuation systems. The demand for these systems in the industry is increasing and the specifications are becoming more challenging. Accurate and fast modeling of the electromagnetic phenomena is therefore required during the design stage to allow for multi-objective optimization of various topologies. This thesis presents a generalized technique to design and analyze 2D electromagnetic problems based on harmonic modeling. Therefore, the prior art is extended and unified to create a methodology which can be applied to almost any problem in the Cartesian, polar and axisymmetric coordinate system. This generalization allows for the automatic solving of complicated boundary value problems within a very short computation time. This method can be applied to a broad class of classical machines, however, more advanced and complex electromagnetic actuation systems can be designed or analyzed as well. The newly developed framework, based on the generalized harmonic modeling technique, is extensively demonstrated on slotted tubular permanent magnet actuators. As such, numerous tubular topologies, magnetization and winding configurations are analyzed. Additionally, force profiles, emf waveforms and synchronous inductances are accurately predicted. The results are within approximately 5 % of the non-linear finite element analysis including the slotted stator effects. A unique passive damping solution is integrated within the tubular permanent magnet actuator using eddy current damping. This is achieved by inserting conductive rings in the stator slot openings to provide a passive damping force without compromising the tubular actuator’s performance. This novel idea of integrating conductive rings is secured in a patent. A method to calculate the damping ratio due to these conductive rings is presented where the position, velocity and temperature dependencies are shown. The developed framework is applied to the design and optimization of a directdrive electromagnetic active suspension system for passenger cars. This innovative solution is an alternative for currently applied active hydraulic or pneumatic suspension systems for improvement of the comfort and handling of a vehicle. The electromagnetic system provides an improved bandwidth which is typically 20 times higher together with a power consumption which is approximately five times lower. As such, the proposed system eliminates two of the major drawbacks that prevented the widespread commercial breakthrough of active suspension systems. The direct-drive electromagnetic suspension system is composed of a coil spring in parallel with a tubular permanent magnet actuator with integrated eddy current damping. The coil spring supports the sprung mass while the tubular actuator either consumes, by applying direct-drive vertical forces, or regenerates energy. The applied tubular actuator is designed using a non-linear constrained optimization algorithm in combination with the developed analytical framework. This ensured the design with the highest force density together with low power consumption. In case of a power breakdown, the integrated eddy current damping in the slot openings of this tubular actuator, together with the passive coil spring, creates a passive suspension system to guarantee fail-safe operation. To validate the performance of the novel proof-of-concept electromagnetic suspension system, a prototype is constructed and a full-scale quarter car test setup is developed which mimics the vehicle corner of a BMW 530i. Consequently, controllers are designed for the active suspension strut for improvement of either comfort or handling. Finally, the suspension system is installed as a front suspension in a BMW 530i test vehicle. Both the extensive experimental laboratory and on-road tests prove the capability of the novel direct-drive electromagnetic active suspension system. Furthermore, it demonstrates the applicability of the developed modeling technique for design and optimization of electromagnetic actuators and devices

Linear actuators for locomotion of microrobots

University of Technology, Sydney. Faculty of Engineering.The successful development of the miniaturisation techniques for electronic components and devices has paved the way for the miniaturisation in other technological fields. In the past two decades, the research achievements in micromechatronics have spurred fast development of micro machines and micro robotic systems. Miniature or micro actuators are the critical components to make these machines more dexterous, compact and cost effective. The main purpose of this dissertation is to develop micro actuators suitable for the locomotion of an in-pipe or endoscopic microrobot. The content of the thesis covers the selection of the actuation principle, robotic system design, actuator design and prototype construction, performance analysis, and design, analysis, and implementation of the appropriate drive control system. Among different types of actuation principles, piezoelectric and electromagnetic actuators are the two major candidates for the micro robotic systems. In order to find a suitable actuation principle for the desired robotic application, a comparative study was conducted on the scaling effects, attainable energy density, and dynamic performances of both types of actuators. Through the study, it was concluded that the electromagnetic actuator is more suitable for the endoscopic microrobot. Linear actuators are the common design used for the locomotion of microrobots due to many advantages compared to their rotational counterparts. Through a thorough review and comparison of the electromagnetic linear actuator topologies, a moving-coil tubular linear actuator was chosen as the first design due to its simplest structure. Via the magnetic circuit analysis and numerical magnetic field solutions, the actuator was designed for optimum force capability, and the electromagnetic force and the machine parameters of the actuator were predicted. According to the results obtained from the magnetic field analysis, the dynamic model of the actuation system with a driving control scheme was established and used in the actuation performance analysis of the robotic system. Based on the experience achieved through the first design, a new moving-magnet tubular linear actuator was designed. The methodology developed in the design and analysis of the moving-coil linear actuator was adopted for the moving-magnet actuator design. However, the optimal design is more complicated due to the multi-pole and multi-phase structure of the moving-magnet actuator. The electromagnetic force of the actuator was analysed under the condition of different excitation methods. An enhanced parameter computation method is proposed for predicting the actuator parameters. Based on the results of magnetic field analysis, a comprehensive dynamic model of the actuator was developed. Through the coupled field-circuit analysis, this model can predict accurately the dynamic performance of the actuator. The characteristics analysis shows that the performance of the moving-magnet actuator is much better than that of the moving-coil actuator. Two prototypes of the moving-magnet tubular linear actuator with different dimensions were constructed to verify the performance and the scaling theory. Various precision machining techniques were employed during the fabrication. The performances and parameters of the two different prototypes were measured and the results agree substantially with the theory. The brushless DC drive method was chosen for the driving control of the proposed linear actuator because of the compact circuit topology and simple implementation, which are two essential factors for micro applications. A sensorless control scheme based on the back EMF was developed as physical position sensors are not permitted in such a micro system. The control scheme was then applied to the locomotion control of the proposed microrobot. The system simulation shows that the control performances of both the actuator and microrobot are satisfactory. A dSPACE prototyping system based driving control hardware was designed and implemented to experimentally verify the control design. The experimental results agree substantially with the theoretical work

Linear electric generator with Halbach array to self-charge a smartphone

Cellular phones have not only function to communicate, but also have e-banking, web surfing, music, and entertainment. The performance of the smartphone has improved because of various functions of smartphone, and capacity of battery has also improved gradually. Although smartphone batteries have been improved compared to conventional batteries, the available usage time of a phone’s rechargeable battery is getting shorter because of the demands of various applications. Therefore, we propose a new tubular permanent magnet linear generator that uses a Halbach array, to send a message or emergency call when the battery is discharged. In order to increase the power generation of existing tubular linear generators, we changed the axial-direction permanent magnet array to a Halbach-type array. When using the Halbach array, it is possible to generate a strong magnetic field without additional magnetic material. In this research, we compared the Halbach array that uses axially and radially magnetized permanent magnets with an existing model that uses an axially magnets. We verified improvement in the amount of power generated with no-load analysis through simulation using the Maxwell commercial electromagnetic analysis software

MODELLING OF LINEAR PERMANENT MAGNET MOTOR FOR AIR-VAPOR COMPRESSOR

Power consumption of refrigerator is the top three among the various household appliances. This is because of the lack performance and efficiency of the conventional refrigerator compressor system. This paper describes about the design of linear permanent magnet motor for reciprocating air-vapor compressor application. There are various types of linear motor technologies and topologies for air-vapor compressor that have been discussed, such as, linear induction machine, linear synchronous machine, linear DC machine, and linear permanent magnet machine. The significant designs criteria considered are based on their force capability, higher efficiency, simplicity and cost-effectiveness. Among the linear motor technologies reviewed, a linear permanent magnet machine is the most preferable technologies for the reciprocating air-vapor compressor application due to the high thrust capability and efficiency. There are three categories of the linear permanent magnet, which are, moving-coil, moving-iron, and moving-magnet. This paper is mainly focused on the moving-magnet topologies which considered a tubular permanent magnet, a slotted and a slotless stator, and also a different type of magnet configuration for the reciprocating air-vapor compressor application. The linear permanent magnet topologies have been studied and analyzed in order to obtain the best three designs for the reciprocating air-vapor compressor application. ANSYS software, ANSOFT Maxwell, is used to draw and analyze the proposed designs to get the results of air-gap flux distribution, air-gap flux density and the respective graph. The result for the three designs will be compared discussed in order to choose one best design for air-vapor compressor application. In conclusion, the best design obtained can be apply for air-vapor compressor to increase efficiency, performance and reduce the energy consumption as well

Minimization of Eddy-Current Loss in a Permanent-Magnet Tubular Linear Motor

This paper presents a minimization of eddy-current loss (ECL) in permanent-magnet (PM) of three tubular linear PM motors (TLPMMs). Three-dimensional Finite-Element Analysis has been used for the simulations. The ECL component is usually not taken into consideration in conventional PM motors. In present technologies, ECL is generated inside magnets of PM motors, due to both the high conductivity of the rare-earth magnets and the harmonics of the slot. This loss can increase the temperature inside the magnets and that may deteriorate their magnetic properties and potential risk of thermal demagnetization. Therefore, in the translator, segmented magnets has been used, because the cancelation of the ECL with this technique is possible as illustrated by the FEA results. Meanwhile, for the stator core of the three proposed motors, soft magnetic composite (SMC) material, Somaloy 700 has been used for its low cost and approximately zero ECL

Tubular permanent magnet actuators: cogging forces characterization

Tubular permanent magnet actuators are evermore used in demanding industrial and automotive applications. However, these actuators can suffer from large cogging forces, which have a destabilizing effect on the servo control system and compromise position and speed control accuracy. This paper focuses on the identification of the cogging forces by means of finite element software, where an approach is introduced within the 2D finite element analysis to model the linear tubular permanent magnet actuator compared to conventional axisymmetrical models. This gives that the contribution of the stator teeth and finite length of the ferromagnetic armature core to the total cogging force can be separately analyzed. The cogging force predictions is characterized and the effectiveness of the new method is verified comparing the results of the tubular structure in both the axisymmetrical model and 2D finite element model, normally used for rotary machines