Electromagnetic muscle actuators

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 181-194).Actuator performance represents a key constraint on the capability of many engineered devices. Performance of these devices is often exceeded by their muscle-powered natural counterparts, inspiring the development of new, "active material" actuators. This thesis reconsiders a traditional actuator, the linear permanent magnet motor, as a form of active material actuator, and presents new, unified scaling and magnetic field models for its performance. This active material motor model predicts that motors composed of large numbers of very small, actively-cooled repeat units, similar to the architecture of biological muscles, can provide greatly enhanced force density over extant designs. Our model is constructed by considering the motor winding as an active material, with its performance limited by the diffusion of waste heat. This allows a quantitative scaling model for the motor constant and force-to-mass ratio to be built for the case of a winding immersed in a homogeneous magnetic field. This model is then modified with a small set of dimensionless parameters to describe the performance penalties imposed by the use of practical sources of magnetic field, specifically periodic arrays of permanent magnets. We explain how to calculate these parameters for a variety of different types of magnet arrays using analytical magnetic field and heat transfer models, and present a new field model for tubular linear motors having improved numerical stability and accuracy. We illustrate the use of our modeling approach with two design case studies, a motor for flapping-wing flying and an actuator for high-performance controllable needle-free jet injection. We then validate our predictions by building and testing a novel water-cooled motor using a tubular double-sided Halbach array of magnets, with a mass of 185 g, a stroke of 16 mm, and a magnetic repeat length of 14.5 mm. This motor generates a continuous force density of 140 N/kg, and has a motor constant of nearly 6 N/[square root]W, both higher than any previously reported motor in this size class.by Bryan Paul Ruddy.Ph.D

Modeling and characterization of a voice coil motor

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 45-46).This thesis describes the development of a voice-coil motor that will allow viscous fluids to be delivered via a portable needle-free injection device. The chosen motor design features opposing magnets whose flux is channeled across the air gap by a center radial magnet, thus creating a higher flux density in the gap compared to a one-magnet design. An analytical model is developed which gives the force of the motor based on the material properties and geometry. An optimized geometry is modeled using finite element analysis, which predicts a motor constant of 11.02 N/[the square root of]W. The motor is fabricated and characterization reveals it to have a motor constant of 8.43 N/[the square root of]W. Althought the motor constant is less than expected, it is a large improvement over the current motor used in needle-free injection, which has a motor constant of 3.21 N/[the square root of]W.by Ashley Brown.S.B

MODELLING AND CONTROL OF MULTI-FINGERED ROBOT HAND USING INTELLIGENT TECHNIQUES

Research and development of robust multi-fingered robot hand (MFRH) have been going on for more than three decades. Yet few can be found in an industrial application. The difficulties stem from many factors, one of which is that the lack of general and effective control techniques for the manipulation of robot hand. In this research, a MFRH with five fingers has been proposed with intelligent control algorithms. Initially, mathematical modeling for the proposed MFRH has been derived to find the Forward Kinematic, Inverse Kinematic, Jacobian, Dynamics and the plant model. Thereafter, simulation of the MFRH using PID controller, Fuzzy Logic Controller, Fuzzy-PID controller and PID-PSO controller has been carried out to gauge the system performance based parameters such rise time, settling time and percent overshoot

Rotary Switched Reluctance Actuator: A Review On Design Optimization And Its Control Methods

A switched reluctance actuator (SRA) is a type of electromagnetic stepper actuator that is gaining popularity for its simple and rugged construction, ability of extremely high-speed operation and hazard-free operation. SRA gained supremacy over permanent magnet actuators due to the fact that its building material are relatively low cost compared to the expensive and rare permanent magnets. SRA is already making its debut in automotive, medical and high precision applications. However, many parties are still oblivious to this new age actuator. This paper reviews the latest literature in terms of journal articles and conference proceedings regarding the different design parameters and control method of SRA. The impact of the parameters on the performance of SRA are discussed in details to provide valuable insight. This paper also discussed the advantages of various novel SRA structure designs that prove to be a huge contribution to the future technology. It is found that several design parameters such as the air gap when kept minimum, increases torque value; while increasing number of phases in SRA minimizes torque ripples. Increased stator and rotor arc angles will increase torque, not to mention a larger excitation current can also achieve the same effect. Researches are often done through Finite Element Method (FEM) analysis to verify the optimized design parameters before fabrication, whilst experimental procedures are executed to verify the simulation results. To ensure smooth phase switching and improved torque output, intelligent controllers are employed in speed control and direct torque control (DTC) methods of SRA

Volume 3 – Conference

We are pleased to present the conference proceedings for the 12th edition of the International Fluid Power Conference (IFK). The IFK is one of the world’s most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists. The Chair of Fluid-Mechatronic Systems at the TU Dresden is organizing and hosting the IFK for the sixth time. Supporting hosts are the Fluid Power Association of the German Engineering Federation (VDMA), Dresdner Verein zur Förderung der Fluidtechnik e. V. (DVF) and GWT-TUD GmbH. The organization and the conference location alternates every two years between the Chair of Fluid-Mechatronic Systems in Dresden and the Institute for Fluid Power Drives and Systems in Aachen. The symposium on the first day is dedicated to presentations focused on methodology and fundamental research. The two following conference days offer a wide variety of application and technology orientated papers about the latest state of the art in fluid power. It is this combination that makes the IFK a unique and excellent forum for the exchange of academic research and industrial application experience. A simultaneously ongoing exhibition offers the possibility to get product information and to have individual talks with manufacturers. The theme of the 12th IFK is “Fluid Power – Future Technology”, covering topics that enable the development of 5G-ready, cost-efficient and demand-driven structures, as well as individual decentralized drives. Another topic is the real-time data exchange that allows the application of numerous predictive maintenance strategies, which will significantly increase the availability of fluid power systems and their elements and ensure their improved lifetime performance. We create an atmosphere for casual exchange by offering a vast frame and cultural program. This includes a get-together, a conference banquet, laboratory festivities and some physical activities such as jogging in Dresden’s old town.:Group 8: Pneumatics Group 9 | 11: Mobile applications Group 10: Special domains Group 12: Novel system architectures Group 13 | 15: Actuators & sensors Group 14: Safety & reliabilit

Development of a knee prosthesis powered by electro-hydrostatic actuation

L'abstract è presente nell'allegato / the abstract is in the attachmen

Design and control of a voice coil actuated robot arm for human-robot interaction

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (leaf 68).The growing field of human-robot interaction (HRI) demands robots that move fluidly, gracefully, compliantly and safely. This thesis describes recent work in the design and evaluation of long-travel voice coil actuators (VCAs) for use in robots intended for interacting with people. The basic advantages and shortcomings of electromagnetic actuators are discussed and evaluated in the context of human-robot interaction, and are compared to alternative actuation technologies. Voice coil actuators have been chosen for their controllability, ease of implementation, geometry, compliance, biomimetic actuation characteristics, safety, quietness, and high power density. Several VCAs were designed, constructed, and tested, and a 4 Degree of Freedom (DOF) robotic arm was built as a test platform for the actuators themselves, and the control systems used to drive them. Several control systems were developed and implemented that, when used with the actuators, enable smooth, fast, life-like motion.by John M. McBean.S.M

Magnetic Contactless Crank-rocker Machine

Objective: In this paper, a proposed technique of motion transmission is introduced, which is based on the crank-rocker principle of motion. The energy transmission action is performed through magnetic force, in which no direct connection is made between the energy source input and the energy load output. Also, to illustrate the concept of motion and to approve the continuity of energy transmission using this proposed technique, a simple model of this mechanism has been built and run, showing the basic sequence of operation. Methodology/analysis: In this mechanical transmission mechanism, one side is rotating and the other side is vibrating, in which any side is energy input (which is usually the vibrating rocker), and the other side is energy output (which is the rotating crank). That seems similar to the classical crank-rocker machine in the four-bar mechanism, but without direct mechanical contact between the input and output energy stream. The concept of motion and mathematical analysis with structuring conditions is provided in this paper, where the dynamic analysis of the system is left for future work. A pilot physical prototype is manufactured and experimentally tested, validating the proposed design. Findings: The structural parameters of this proposed contactless crank-rocker machine have been modelled and simulated using the MATLAB program. It shows that these parameters could be selected and optimized to guarantee the minimum conditions for continued energy transmission. Based on these parameters, a simple model has been built and operated, which illustrates the concept of motion and validates the finding of MATLAB simulation. Novelty/improvement:Contactless crank-rocker motion is a very promising technique. It is possible to apply it in many applications, like the energy harvesting area, and it could be employed certainly in specific designs, such as MEMS, where no other motion transmission types can be used. Doi: 10.28991/ESJ-2022-06-02-07 Full Text: PD