Mostrando recursos 1 - 20 de 377
Zhang, Grace H.; Braverman, Boris; Kawasaki, Akio; Vuletic, Vladan
We present a mechanical laser shutter design that utilizes a direct current electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade’s range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 ± 0.02) m/s with 1 ms activation delay and 10 μs jitter in its timing performance. The shutter design is simple, easy...
Reichhartinger, M; Spurgeon, SK; Weyrer, M
Electric power steering (EPS) systems assist the driver during manoeuvres by applying an additional steering torque generated by an electric motor. Although there are many advantages for electric actuated steering systems including fuel efficiency, they are known to deteriorate the feel of the steering as experienced by the driver. This paper presents a sliding mode observer based estimation concept which provides signals to evaluate and improve perception and feel of the steering as experienced by the driver. The proposed strategy is based on a physically motivated dynamic model of a power steering system and the measurements considered are typically available...
Design Principles for Energy-Efficient Legged Locomotion and Implementation on the MIT Cheetah Robot
Seok, Sang Ok; Wang, Albert D; Chuah, Meng Yee; Hyun, Dong Jin; Lee, Jongwoo; Otten, David M; Lang, Jeffrey H; Kim, Sangbae
This paper presents the design principles for highly efficient legged robots, the implementation of the principles in the design of the MIT Cheetah, and the analysis of the high-speed trotting experimental results. The design principles were derived by analyzing three major energy-loss mechanisms in locomotion: heat losses from the actuators, friction losses in transmission, and the interaction losses caused by the interface between the system and the environment. Four design principles that minimize these losses are discussed: employment of high torque-density motors, energy regenerative electronic system, low loss transmission, and a low leg inertia. These principles were implemented in the...
Investigating the trade-offs involved in augmenting a DC brushless motor with an active heat sink in order to improve performance.
Browne, Deron Adriel
This thesis seeks to establish solutions to the issue of electric motor heating and the problems it presents for use of these motors in biomechatronic applications. As electric motors are used, their windings heat up and the resulting temperature limits torque. Larger motors may be used to obtain more torque, but this adds undesirable weight to the devices in which they are used. Cooling methods also exist, but do not necessarily consider suitability to bionic applications. This thesis therefore aims to improve the torque output of a given motor by effectively removing heat while minimizing the addition of mass. I...
In today’s society, there is growing concern over the state of the global climate and the impact that we have on it. Scientists and engineers are seeking ways to meet energy demands and emissions regulations around the world by creating more sustainable and energy efficient technologies. In the automotive industry, this can be evidenced by the advent of hybrid electric vehicles. The Ohio State University EcoCAR 3 team based at the Center for Automotive Research is converting a 2016 Chevrolet Camaro into a plug-in hybrid electric vehicle with the end goal of improving fuel consumption and emissions whilst maintaining the...
D. Kiš; T. Jurić; N. Voća; Duška Čurić; M. Mandurić
Recipes determine the quality of livestock feed and the hydraulic adders are one of the elements determining if the given recipe will be carried out. Generally, construction of existing adders does not allow accomplishment of that aim i.e. they do not meet recipe requirements. Consequently, researches which determined deviations in ingredient adding present with existing adders and with the experimental hydraulic adder were conducted. The research was conducted for two years (2005 and 2006) in two livestock feed factories in the Republic of Croatia on samples of feed mixtures for pigs weighing up to 15 and 25 kilos. Relative error...
D Ghanbarian; A Ghorbani-marghmaleki; M.A Ghazavi; Sh Besharati
Introduction: Iran is one of the major producers of almonds. According to the statistics released by FAO (2011), Iran with more than 110000 tons of almonds is the third in rank throughout the world. However, most Iranian almonds are presented as an unsorted and unpackaged product. Some producers sort their products by hand which is very time-consuming and labor-intensive. So, there is an essential need for suitable grading and packaging machines especially for the export of almond kernels.Grading, which is sometimes called sorting, is basically separating the material in different homogenous groups according to its specific characteristics like size, shape,...
Investigating the effect of tractive parameters on imposed vertical stresses under driving wheel using a soil bin test rig facility
H Taghavifar; A Mardani
Introduction: Tire tractive parameters of the driving wheel are of the most substantial factors for the evaluation of the performance of agricultural tractors. Great tractive efficiency has called the attention of vehicle designers to attain economic efficiency owing to the minimization of fuel consumption. At terrain-tire interface, some soil physical-mechanical changes occur that lead to unwanted soil compaction. Of the influential parameters for the creation of soil compaction is the soil stresses formed owing to the wheeled vehicle trafficking. While the increase of tractive efficiency is desired, minimization of soil stresses should also be considered with the same importance to...
James B Snyder; Mark E Nelson; Joel W Burdick; Malcolm A Maciver
Active sensing organisms, such as bats, dolphins, and weakly electric fish, generate a 3-D space for active sensation by emitting self-generated energy into the environment. For a weakly electric fish, we demonstrate that the electrosensory space for prey detection has an unusual, omnidirectional shape. We compare this sensory volume with the animal's motor volume--the volume swept out by the body over selected time intervals and over the time it takes to come to a stop from typical hunting velocities. We find that the motor volume has a similar omnidirectional shape, which can be attributed to the fish's backward-swimming capabilities and...
Alejo Rodríguez-Cattaneo; Ana Carolina Pereira; Pedro A Aguilera; William G R Crampton; Angel A Caputi
Understanding fixed motor pattern diversity across related species provides a window for exploring the evolution of their underlying neural mechanisms. The electric organ discharges of weakly electric fishes offer several advantages as paradigmatic models for investigating how a neural decision is transformed into a spatiotemporal pattern of action. Here, we compared the far fields, the near fields and the electromotive force patterns generated by three species of the pulse generating New World gymnotiform genus Gymnotus. We found a common pattern in electromotive force, with the far field and near field diversity determined by variations in amplitude, duration, and the degree...
Comparative evaluation of light-trap catches, electric motor mosquito catches and human biting catches of Anopheles in the Three Gorges Reservoir.
Wang Duo-quan; Tang Lin-hua; Gu Zhen-cheng; Zheng Xiang; Yang Man-ni; Jiang Wei-kang
The mosquito sampling efficiency of light-trap catches and electric motor mosquito catches were compared with that of human biting catches in the Three Gorges Reservoir. There was consistency in the sampling efficiency between light-trap catches and human biting catches for Anopheles sinensis (r = 0.82, P<0.01) and light-trap catches were 1.52 (1.35-1.71) times that of human biting catches regardless of mosquito density (r = 0.33, P>0.01), while the correlation between electric motor mosquito catches and human biting catches was found to be not statistically significant (r = 0.43, P>0.01) and its sampling efficiency was below that of human biting catches. It is concluded that light-traps can...
A. Mansouri; T. Hafedh
Recently, electric vehicle motoring has become a topic of interest, due to the several problems caused by thermal engines such as pollution and high oil prices. Thus, electric motors are increasingly applied in vehicle’ applications and relevant research about these motors and their applications has been performed. Of particular interest are the improvements regarding torque production capability, the minimization of torque ripple and iron losses. The present work deals with the optimum design and the performance investigation of an outer rotor permanent magnet motor for in-wheel electric vehicle application. At first, and in order to find the optimum motor design,...
Enno Sabelberg; Maria Cardenas; Reinhold Kneer; Wilko Rohlfs
Efficient liquid cooling systems in cutting and chipping processes are essential to remain below the temperature limits of the cutting tool and materials. Impinging jet cooling near the processing location is a widely employed technique for this purpose. The cooling effect can be optimized using a pulsating cooling fluid to improve heat transfer, via a periodic renewal of the hydrodynamic and thermal boundary layer. This study focuses on a cooling nozzle which generates a passive jet excitation, without an electric motor or any valve system. Four different nozzle design mechanisms for the jet excitation were developed and tested with respect to...
Jozef Mascenik; Slavko Pavlenko; Imrich Vojtko
The paper deals with the alternative of determination of state of the belt gear. To realize themeasurements a newly developed device was designed for measurement and diagnostics of the belt gears. The main task is to detect the V-belt slip expressed by the coefficient of elastic creep and of specific slip with a measuring device. The measurements regarding can be performed if input revolutions of the electric motor and torque of the belt gear are constant whereas the tensioning force of the belt gear changes. It is also possible to perform the measurement if the input revolutions of the electric...
For many industrial applications that including ele ctric motor, selecting of the appropriate motor type is keypoint for the application success and efficiency. This paper presents a comparative performance evaluation between direct t orque controlled Brushless AC and Brushless DC motors which have been considered as t raction motor on electric vehicles. Moreover, a short review to brushless AC and brushl ess DC motor technology and vector driver systems are also included. The main structure of th e direct torque control method is presented and small-scale pure electric vehicle model is inte grated to the motor control model. To make a fair comparison, the brushless AC...
Intraoperative Neurophysiological Monitoring for Endoscopic Endonasal Approaches to the Skull Base: A Technical Guide
Harminder Singh; Richard W. Vogel; Robert M. Lober; Adam T. Doan; Craig I. Matsumoto; Tyler J. Kenning; James J. Evans
Intraoperative neurophysiological monitoring during endoscopic, endonasal approaches to the skull base is both feasible and safe. Numerous reports have recently emerged from the literature evaluating the efficacy of different neuromonitoring tests during endonasal procedures, making them relatively well-studied. The authors report on a comprehensive, multimodality approach to monitoring the functional integrity of at risk nervous system structures, including the cerebral cortex, brainstem, cranial nerves, corticospinal tract, corticobulbar tract, and the thalamocortical somatosensory system during endonasal surgery of the skull base. The modalities employed include electroencephalography, somatosensory evoked potentials, free-running and electrically triggered electromyography, transcranial electric motor evoked potentials, and auditory...
Julius Caesar Puoza; Frimpong Opoku; Bernard Aboagye
A motorized cassava fufu pounding machine was developed and tested. The machine principal parts were hopper, throat, pounding compartment, discharge outlet, main frame, electric motor seat, auger, shaft and pulleys. Mild steel material and stainless steel sheet were used in the fabrication based on its availability, strength, appearance, cost, and corrosion resistance. The machine is powered by a 5hp electric motor; the dimension of the machine is 1010mm × 600mm × 930mm (length × breadth × height). Output capacity of 120kg/hr was obtained. The machine is affordable and easy to operate and manage. It is therefore recommended for the restaurants,...
Ashfaq Ahmed Pathan; Rasool Bux Mahar; Kamran Ansari
The characteristics of the greywater vary from country to country and it depends upon the cultural and social behavior of the respective country. There was a considerable need to characterize and recycle the greywater. In this regard greywater was separated from the black water and analyzed for various physiochemical parameters. Among various greywater recycling treatment technologies, RBC (Rotating Biological Contactor) is more effective treatment technique in reducing COD (Chemical Oxygen Demand) and organic matters from the greywater. But this technology was not applied and tested in Pakistan. There was extensive need to investigate the RBC technology for greywater recycling at small scale before applying at mass scale. To...
Design of a Load Torque Based Control Strategy for Improving Electric Tractor Motor Energy Conversion Efficiency
Mengnan Liu; Liyou Xu; Zhili Zhou
In order to improve the electrical conversion efficiency of an electric tractor motor, a load torque based control strategy (LTCS) is designed in this paper by using a particle swarm optimization algorithm (PSO). By mathematically modeling electric-mechanical performance and theoretical energy waste of the electric motor, as well as the transmission characteristics of the drivetrain, the objective function, control relationship, and analytical platform are established. Torque and rotation speed of the motor’s output shaft are defined as manipulated variables. LTCS searches the working points corresponding to the best energy conversion efficiency via PSO to control the running status of the...
Nnamdi Anosike; Emmanuel Brown; Chukwnonso Maduka
The drudgery involved in dehulling breadfruit seed by traditional methods has been highlighted as one of the major problems hindering the realization of the full potential of breadfruit as a field to food material. This paper describes a development in an African breadfruit seed dehulling machine with increased throughput of about 70% above reported machines. The machine consists of a 20 mm diameter shaft, carrying a spiral wound around its circumference (feeder). The feeder provides the required rotational motion and turns a circular disk that rotates against a fixed disk. The two disks can be adjusted to maintain a pre-determined...