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Sony XNV-660BT 6.1-Inch WVGA In-Dash A/V Receiver with Bluetooth, USB, Satellite/HD radio ready, and Integrated Navigation from TomTom List Price: $899.95 Sale Price: $499.96 |
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With the most accurate maps and over 1 million more miles of road in the US than others, plus features like USB 1-Wire connectivity and Bluetooth technology, you're ready for the road trip of a lifetime and your daily commute with the Sony XNV660BT 6.1" Touchscreen A/V Receiver with Navigation. The Sony XNV-660BT A/V Receiver with Navigation delivers incredible audio and video picture quality and integrates navigation from TomTom. With the most accurate maps and over 1 million more miles of road in the US than others, plus features like USB 1-Wire connections and Bluetooth technology, you're ready for the road trip of a lifetime--not to mention your daily commute. Incredible audio and video picture quality and integrated navigation from TomTom. Click to enlarge. Incredible Audio/Video Picture Quality 6.1-Inch Touchscreen Display High-resolution TFT (WVGA) 6.1-inch touch screen display that will inform and entertain you, making everything easier to control with gesture command and on-screen touch buttons. Separate audio and video power supply circuits provide added clarity. TomTom navigation provides the most accurate maps with over 1 million more miles of road in the US than other GPS brands. Bring the TomTom Navigation Module from your car and connect to your computer via USB for updates. Control everything easily with gesture command and on-screen touch buttons. USB 1-Wire Connectivity Connect, charge, and control your iPod, iPhone, Walkman player or other compatible USB devices via the USB 1-Wire on the rear of the unit. You can also view metadata like song title and artist on the front display. Integrated Bluetooth Technology Taking calls and enjoying streaming audio has never been easier with the XNV-660BT A/V Receiver with Navigation featuring Bluetooth technology. Connect compatible devices and easily choose between Hands Free and Phone Book Access or Audio Streaming. Plays DVDs/CDs and Digital Files The XNV-660BT A/V Receiver with Navigation accepts just about every digital format you'd want on the road. The XNV-660BT can playback CD or DVD and MP3/WMA/AAC/JPEG/MP4 (Simple Profile) CODEC files. Satellite Radio/HD Radio Ready The XNV-660BT integrates seamlessly with Satellite Radio and HD Radio using Sony Bus adaptors so you can receive digital satellite radio or HD Radio broadcasts. Advanced Sound Engine With EQ7 The Advanced Sound Engine uses EQ7 equalizer, adjustable LPF/HPF crossovers, Listener Position calibration, DM+ advanced sound restoration, Rear Bass Enhancer, and Center Stage Optimizer to create an ideal in-car listening environment. Integrated Navigation From TomTom The Sony XNV-660BT A/V Receiver with Navigation features TomTom navigation and delivers incredible audio and video picture quality. TomTom is the only company to incorporate real world, real-time feedback, providing the most accurate maps available. Preloaded Maps of US and Canada TomTom navigation provides the most accurate maps with over 1 million more miles of road in the US than other GPS brands.One Year Free Map Updates Ensuring that the digital map content remains completely up-to-date. Included in the box provides 4 verified US and Canada map updates for the first year.TomTom Home Software TomTom Home makes it easy to get new software, download new maps, access free content and more. Simply bring the exclusively designed TomTom Navigation Module from your car and connect to your computer via USB.IQ RoutesTomTom IQ Routes Technology puts the driving experience of millions of TomTom users into your maps to shave time off even the shortest trips. Calculates the fastest route possible based on time of day. With TomTom IQ Routes you'll always drive the smartest, most efficient route. IQ Routes saves you time, fuel and money. Traffic isn't the same during Monday morning rush hour as it is on a lazy Sunday afternoon. Heavy traffic, rotaries, traffic lights, and even pedestrians can slow you down. The route you need changes depending on the day and time, so the shortest route isn't necessarily going to be the fastest. With TomTom IQ Routes you'll always drive the fastest route. Advanced Lane Guidance* TomTom Advanced Lane Guidance gives you extra clarity when navigating difficult junctions by showing you which lane to take, so you won't miss your turn or have to make sudden, dangerous lane crossings. Photorealistic images and a pulsing green arrow indicate exactly which lane to use, so you can go confidently. Spoken Street Names When driving to your destination, the XNV-770BT will announce turn-by-turn directions, including street and place names. 6 Million Points of Interest Preloaded with the locations of millions of gas stations, restaurants, hotels, hospitals and more. QuickGPSfix GPS data that predicts satellite positions and enables quicker GPS pick-up. Faster satellite pick-up means quicker start to the journey. Help Me! Emergency Resources Menu Comprehensive Help Me! menu to assist in any emergency. Quickly obtain address information to the nearest help location (hospital, police station, etc.). First aid guide also provides info on what to do if an accident occurs. *Feature only available in the US and Canada What's in the Box Sony XNV-660BT A/V Receiver with Navigation, RM-X170 Wireless Remote, CD-ROM (Application Disc), Installation Hardware, Microphone, Navigation Module, User's Manual, Installation Manual About TomTom Founded in Amsterdam in 1991, TomTom has established itself as a global leader in navigation by being an innovative company with a strong brand, clear customer focus, and high quality products and services. TomTom is the world's leading navigation solutions provider with navigation products sold in 30 countries and in over 20 languages. To further our commitment to car navigation, TomTom acquired Tele Atlas maps in 2008 so we can continually provide the most up-to-date maps and intelligent routing. We have our own mapping company! Did you know that every year roads change by up to 40% in high-growth areas? Tele Atlas manages this by using the world's most comprehensive systems to identify and incorporate these changes into our maps with unprecedented levels of speed and accuracy. All TomTom devices benefit from the Tele Atlas advantage--more coverage, more points of interest, and more freshness and accuracy. Why TomTom? At TomTom, we believe that personal navigation should be as easy and safe as possible. We develop smart technology that gives you straightforward solutions, innovations to make life easy. |
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Sony XNV-770BT 7-Inch WVGA In-Dash A/V Receiver with Bluetooth, USB, Satellite/HD radio ready, and Integrated Navigation from TomTom List Price: $1,199.95 |
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With the most accurate maps and over 1 million more miles of road in the US than others, plus features like USB 1-Wire connectivity and Bluetooth technology, you're ready for the road trip of a lifetime and your daily commute with the Sony XNV660BT 7" Touchscreen A/V Receiver with Navigation. The Sony XNV-770BT A/V Receiver with Navigation delivers incredible audio and video picture quality, with integrated navigation from TomTom. With the most accurate maps and over 1 million more miles of road in the US than others, plus features like USB 1-Wire connections and Bluetooth technology, you're ready for the road trip of a lifetime--not to mention your daily commute. Incredible audio and video picture quality and integrated navigation from TomTom. Click to enlarge. Incredible Audio/Video Picture Quality 7-Inch Touchscreen Display The high-resolution TFT (WVGA) 7-inch touchscreen display that will inform and entertain you, making everything easier to control with gesture command and on-screen touch buttons. Separate audio and video power supply circuits provide added clarity. TomTom navigation provides the most accurate maps with over 1 million more miles of road in the US than other GPS brands. Bring the TomTom Navigation Module from your car and connect to your computer via USB for updates. Control everything easily with gesture command and on-screen touch buttons. USB 1-Wire Connectivity Connect, charge, and control your iPod, iPhone, Walkman player or other compatible USB devices via the USB 1-Wire on the rear of the unit. You can also view metadata like song title and artist on the front display. Integrated Bluetooth Technology Taking calls and enjoying streaming audio has never been easier with the XNV-770BT A/V Receiver with Navigation featuring Bluetooth technology. Connect compatible devices and easily choose between Hands Free and Phone Book Access or Audio Streaming. Plays DVDs/CDs and Digital Files The XNV-770BT A/V Receiver with Navigation accepts just about every digital format you'd want on the road. The XNV-770BT can playback CD or DVD and MP3/WMA/AAC/JPEG/MP4 (Simple Profile) CODEC files. Satellite Radio/HD Radio Ready The XNV-770BT integrates seamlessly with Satellite Radio and HD Radio using Sony Bus adaptors so you can receive digital satellite radio or HD Radio broadcasts. Advanced Sound Engine With EQ7 The Advanced Sound Engine uses EQ7 equalizer, adjustable LPF/HPF crossovers, Listener Position calibration, DM+ advanced sound restoration, Rear Bass Enhancer, and Center Stage Optimizer to create an ideal in-car listening environment. Integrated Navigation from TomTom The Sony XNV-770BT A/V Receiver with Navigation features TomTom navigation and delivers incredible audio and video picture quality. TomTom is the only company to incorporate real world, real-time feedback, providing the most accurate maps available. Preloaded Maps of US and Canada TomTom navigation provides the most accurate maps with over 1 million more miles of road in the US than other GPS brands.One Year Free Map Updates Ensuring that the digital map content remains completely up-to-date. Included in the box provides 4 verified US and Canada map updates for the first year.TomTom Home Software TomTom Home makes it easy to get new software, download new maps, access free content and more. Simply bring the exclusively designed TomTom Navigation Module from your car and connect to your computer via USB.IQ RoutesTomTom IQ Routes Technology puts the driving experience of millions of TomTom users into your maps to shave time off even the shortest trips. Calculates the fastest route possible based on time of day. With TomTom IQ Routes you'll always drive the smartest, most efficient route. IQ Routes saves you time, fuel and money. Traffic isn't the same during Monday morning rush hour as it is on a lazy Sunday afternoon. Heavy traffic, rotaries, traffic lights, and even pedestrians can slow you down. The route you need changes depending on the day and time, so the shortest route isn't necessarily going to be the fastest. With TomTom IQ Routes you'll always drive the fastest route. Advanced Lane Guidance* TomTom Advanced Lane Guidance gives you extra clarity when navigating difficult junctions by showing you which lane to take, so you won't miss your turn or have to make sudden, dangerous lane crossings. Photorealistic images and a pulsing green arrow indicate exactly which lane to use, so you can go confidently. Spoken Street Names When driving to your destination, the XNV-770BT will announce turn-by-turn directions, including street and place names. 6 Million Points of Interest Preloaded with the locations of millions of gas stations, restaurants, hotels, hospitals and more. QuickGPSfix GPS data that predicts satellite positions and enables quicker GPS pick-up. Faster satellite pick-up means quicker start to the journey. Help Me! Emergency Resources Menu Comprehensive Help Me! menu to assist in any emergency. Quickly obtain address information to the nearest help location (hospital, police station, etc.). First aid guide also provides info on what to do if an accident occurs. *Feature only available in the US and Canada What's in the Box Sony XNV-770BT A/V Receiver with Navigation, RM-X170 Wireless Remote, CD-ROM (Application Disc), Installation Hardware, Microphone, Navigation Module, User's Manual, Installation Manual About TomTom Founded in Amsterdam in 1991, TomTom has established itself as a global leader in navigation by being an innovative company with a strong brand, clear customer focus, and high quality products and services. TomTom is the world's leading navigation solutions provider with navigation products sold in 30 countries and in over 20 languages. To further our commitment to car navigation, TomTom acquired Tele Atlas maps in 2008 so we can continually provide the most up-to-date maps and intelligent routing. We have our own mapping company! Did you know that every year roads change by up to 40% in high-growth areas? Tele Atlas manages this by using the world's most comprehensive systems to identify and incorporate these changes into our maps with unprecedented levels of speed and accuracy. All TomTom devices benefit from the Tele Atlas advantage--more coverage, more points of interest, and more freshness and accuracy. Why TomTom? At TomTom, we believe that personal navigation should be as easy and safe as possible. We develop smart technology that gives you straightforward solutions, innovations to make life easy. |
Here are some more information for Point Harness Rotary:
It seems like Funeral Directors are going "Facebook Crazy" - every day I am receiving friend requests from Funeral Directors and seeing Funeral Homes creating profiles, pages, and groups.
The problem is that I see a ton of mistakes being made - most inadvertently because there is not a lot of direction and guidance available on HOW to use Facebook properly for the Funeral Industry.
There is no Best Practices for Funeral Homes and Facebook (not yet anyway) but I have been really digging deep into what IS the best way for funeral directors to harness the power of Facebook from a Relationship & Loyalty Building (Marketing) strategy without crossing the line of doing business in a social community.
You have heard me say it before - and this won't be the last time - the funeral industry is a "relationship business" where people serve people and buildings, cars, and merchandise are secondary. When my Great-Grandfather started the undertaking business, and my Grandfather took it over - they built it on building relationships within their community. They did this by being involved in various networks of the day - Church, Lodge, Rotary, Town Council, etc. Fast forward 75 years and networks within communities are still very important - they may be the same networks as they used to be or may be different ones.
Even though Facebook is a virtual community, it is growing faster than any other network of
people in your community. Let's take a look at some of the numbers (Source CheckFacebook.com as of May 18, 2009 - pretty current eh!):
Global Audience: 192,406,840
- United States 60,989,380
- United Kingdom 17,839,940
- Canada 11,443,520
- Turkey 9,531,440
- France 9,510,400
- Italy 9,424,120
- Australia 5,599,000
- Colombia 4,568,280
- Chile 4,504,560
- Spain 4,478,380
United States Age Distribution:
- 18 - 24: 30.6% (18,338,140)
- 25 - 34: 27.6% (16,535,280)
- 35 - 44: 17.7% (10,592,180)
- 14 - 17: 10.2% (6,089,780)
- 45 - 54: 8.4% (5,023,380)
- 55 - 65: 3.6% (2,164,420)
- 65+: 1.4% (861,340)
- 0 - 13: 0.6% (348,340)
The 55 and over crowd have over 3 million members in the US. For perspective if this group of 55+ Facebook users were a city - it would be the 3rd largest between LA and Chicago.
One last thing before I get into the 7 Mistakes Funeral Directors make with Facebook is that there are more females on Facebook than men:
- Females: 57.4% (34,657,940)
- Males: 42.6% (25,677,840)
We know women make more buying decisions than men and we have also been told that women regard relationships as very important (hopefully us guys have figured that out by now).
7 Mistakes Funeral Directors Make with Facebook
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Not On Facebook Yet
lease see the stats above - if you're not on Facebook yet, I included those stats for you - don't worry, it's not too late, sign up today. When you do sign up, please add me as a friend -
Non-Passionate Status Updates: "Monday again, Hump Day, TGIF, Work Sucks" plus others that I can't repeat
- I know that it's not all about work, but as funeral professionals we are always in the public eye - even online; keep the venting to private conversations - you never know if a family member can see your status even when your privacy settings are set
-
Not Showing Families How to Add Obits to their Profile: Let family members promote your online obits to their Facebook community.
- Whether you have a Facebook profile or not you can harness the power of Facebook to drive traffic to your online obituaries by teaching families how to add their loved one's obit into their profile so that all of their friends can see it, and then go to your site to leave a condolence
- When I look at my clients' Google Analytics (website stats) I am amazed that Facebook is usually in the Top 5 Referrers category
- Sample from McCallBros.com: Add An Obituary To Facebook
-
Creating a PROFILE for the Funeral Home instead of a PAGE: Profiles are for People and Pages are for Businesses
If you have your Profile as your Funeral Home and not you personally, here's what you do:
- Create a Profile under your Personal name and once you have built up your profile, then invite all of the Friends from the first profile to your new one
- Create a Page under the Funeral Home name and copy all of the pertinent information over - then once it is established you can start to invite people to become a "Fan"
- Not "Claiming" your Memorable Web Address for your Profile and Business Page: Do not let your competitor "Claim Your Name"
-
Having A "Profile" Picture that is Too STIFF: Is your profile picture with you in your "Stripes" or other Funeral Attire?
- You want to connect with your "Community" - the more they can relate to you (as a parent, spouse, soccer coach, etc.) the better - could you change your picture so that you could be "more like them?"
- NOTE: "But Hepp, your profile picture is you in a suit!" Exactly - see the previous bullet point -... connect with 'your' community
-
Do Not Actively Build Your Friend List: The more people that you can connect with in your community, the better - it will not hurt you to have too many friends on Facebook - well, until you hit the maximum of 5,000
- Here are 3 ways to grow your "Friends" list
- Upload your "Contacts" from your Outlook or Outlook Express
- View the Friends of the Most Popular people in your community and "Add as Friend" if you think that it is appropriate to do so
- Search Groups and Fan Pages for Local Organizations like Chamber of Commerce, Rotary, Church Groups, etc.
- Here are 3 ways to grow your "Friends" list
NOTE: Just a little bit of advice - create Lists to segment your Friends such as Family, School Friends, Funeral Peers, [Your Town's Name] Connections, etc. You will thank me later.
May 18, 2009
Robin Heppell, CFSP, combines his expertise in technology and pre-need, his formal business knowledge and his deep-rooted legacy in the funeral profession so that he can help funeral homes and cemeteries be more competitive, more profitable, and provide the best possible service for the families they serve.
Through his consulting firm, FuneralFuturist.com in Victoria, British Columbia, he assists funeral directors and cemeterians throughout North America embrace and incorporate innovative strategies and technologies.
This "Funeral Futurist" has over 20 years experience in a highly competitive, high cremation (90%) market. He is a fourth generation funeral director and a Certified Celebrant. Heppell is also a faculty member of the Canadian College of Funeral Service, a contributor to Mortuary Management and the Canadian Funeral News.
Internet Marketing for Funeral Professionals >>> Visit http://www.FuneralFuturistU.com.
Emerging technologies in electrical drives and power distribution systems in future aircrafts
Emerging technologies in electrical drives and power distribution systems in future aircrafts
u.sureshkumar*
* professor in EEE department
Mohamed sathak enginnering college
Kilakkarai
E mail :uskrk@sify.com
Abstract:
It is projected that in future aircraft, all power, except propulsion, will be distributed and processed electrically. In other words, electrical power will be utilized for driving aircraft subsystems currently powered by hydraulic, pneumatic or mechanical means including utility and flight control actuation, environmental control system, lubrication and fuel pumps, and numerous other utility functions. These concepts are embraced by what is known as the “More Electric Aircraft (MEA)” initiative. The MEA emphasizes the utilization of electrical power as opposed to hydraulic, pneumatic, and mechanical power for optimizing aircraft performance and life cycle cost. It would eliminate the need for gearboxes and transmissions since the power transmission is through electrical rather than mechanical means, which reduces the weight of the aircraft and increases the fuel efficiency. Detailed analysis of
interaction between an Electro Mechanical Actuator (EMA) connected to the DC bus of the power distribution system in a next generation transport aircraft with the bus regulator is presented. Development of reliable power-by-wire actuation systems for both aeronautical and space applications has been sought recently to eliminate hydraulic systems from aircraft. Aircraft
engineers have tested electrohydrostatic actuators (EHAs), which combine electrical and hydraulic power, hence the
evolutionary "more electric aircraft" idea. Efforts are being made to replace
all the hydraulic systems with electrical systems, which will lead to a new technology called “All Electric Aircraft”.
Introduction:
Flight Control System
A flight control system consists of the flight control surfaces, the respective cockpit controls, connecting linkage, and necessary operating mechanism to cont4rol aircraft in flight.
Classification
Flight control systems (FCS) are classified as follows:
- Mechanical FCS
- Hydro mechanical FCS (powered flight control units (PFCU))
- Fly-by-wire FCS
Mechanical FCS:
The mechanical FCS is the most basic designs. They were used in early aircraft and currently in small aeroplanes where the aerodynamic forces are not excessive. The FCS uses a collection of mechanical parts such as rods, cables, pulleys and sometimes chains to transmit the forces of the cockpit controls to the control surfaces.
Hydro mechanical FCS (powered flight control units (PFCU)):
The complexity and weight of a mechanical FCS increases considerably with size and performance of the airplane. Hydraulic power overcomes these limitations
A hydraulic FCS has 2 parts:
- The mechanical circuit
- The hydraulic circuit
The mechanical circuit links the cockpit controls with the hydraulic circuits. Like the mechanical FCS, it is made of rods, cables, pulleys, and sometimes chains. The hydraulic circuit has hydraulic pumps, pipes, valves and actuators. The hydraulic pressure generated by the pumps in the hydraulic circuit powers the actuators. The actuators convert hydraulic pressure into control surface movements. The servo valves control the movement of the actuators. The above two-control system has a major drawback that it contains heavy mechanical circuitry, which increases the weight of the system. To overcome this drawback a new technology “MORE ELECTRIC TECHNOLOGY IN AIRCRAFT” was developed. The aircraft in which this technology was used was called “MORE ELECTRIC AIRCRAFT”(MEA).
When describing the MEA, flight control actuation systems can be considered to involve two main technological areas: fly-by-wire (FBW) and power-by-wire (PBW). FBW technology comprises the design, development and implementation of electronics for flight control systems. Electronic control provides flight control and actuator control functionality implemented using either centralized or distributed architectures. Distributed control systems reduce the processing load on centralized flight control computers, and offer more flexibility during system architecture development. A further benefit is the reduction in weight achieved by reducing harness size and component quantity. In recent years, technological advancement has centered on the FBW field, to the extent that FBW control systems are now the standard in today’s commercial and military aircraft. Power-by-wire (PBW) actuation is the next major breakthrough in aircraft control. Just as the fly-by-wire flight control system eliminated the need for mechanical interfaces, power-by-wire actuators eliminate the need for central hydraulic systems. Control power comes directly from the aircraft electrical system. This has several advantages. Central hydraulic systems are complicated and difficult to maintain. Removing these systems would greatly reduce the amount of support equipment and personnel required to maintain and operate current air and space vehicles. In addition, PBW actuators have the potential to be more efficient than their hydraulic counterparts. A central hydraulic system must generate and sustain significant hydraulic pressure (3,000 to 6,000 pounds per square inch) at all times, regardless of demand. PBW actuators only use electrical power when needed. Finally, PBW actuation systems can be made far more fault tolerant than those depending on a central hydraulic supply. Once a hydraulic line is compromised, it usually leads to the loss of that entire hydraulic circuit. As a result, multiple hydraulic circuits are required to maintain some level of redundancy. With a PBW system, a failed actuator can simply be switched off, isolating the problem to a single surface.
Types of PBW Actuators
There are several different types of PBW actuators, including electrohydrostatic actuators (EHA) and electromechanical actuators (EMA). EHAs use a reversible, electrically driven pumpmotor to directly pump self-contained hydraulic fluid to a piston. This drives the ram in the same fashion as a standard hydraulic actuator (Figure 1(a)). An EMA has no internal hydraulic fluid, instead using electric motors to directly drive the ram through a mechanical gearbox (Figure 1(b)). Compared to an EHA, the EMA has certain advantages. It is lighter, smaller, and less complex than an equivalent EHA because of the absence of an internal hydraulic system. Since there is no hydraulic fluid in the load path, the EMA tends to be stiffer than an equivalent EHA. The EMA tends to be more efficient because there are no windage losses or pump inefficiencies. Finally, since there is no leak potential with an EMA, it is better suited to long term storage or space applications.
Electromechanical Actuation (EMA)
An EMA uses mechanical gearing to couple an electric motor to a flight control surface. This is achieved using a rotary gearbox, and depending on the actuation method required, can include some form of rotary-to-linear conversion, such as a ball screw. Electric motors requiring a DC electrical supply are typically used, although the addition of a diode rectification stage will also allow them to operate from an AC electrical supply. Motor speed, direction, and torque translate directly to speed, direction, and load in the actuator. Figure 1 shows an EMA currently being developed by TRW for a high-power flight control application. In its basic form, the EMA is susceptible to certain single-point failures that can lead to a mechanical jam, and consequently presents complications for flight certification on certain surfaces. Additional devices can be used to mitigate against this failure mode, but in doing so, complexity, cost, and weight are increased. For these reasons, the basic EMA is not suited for primary flight control applications. However, spoiler systems and secondary actuation systems could accommodate EMA technology.
EMA system layout
Large EMA for High-Power flight controls
Baseline Power System Architecture
The proposed power distribution system is built around a 270V DC distribution bus. The typical baseline power system architecture for a next generation aircraft is shown in Fig. 1. It can be seen that the key components that control the power are the bidirectional power converters (BDCs). A bus regulator provides an interface between the starter/generator and the distribution bus. Most of the loads, including the actuators, are regulated using bidirectional power converters, which control and condition the power from the DC bus.
With the proliferation of bidirectional power converters and advanced actuators in the power distribution system, it is important to develop methods to analyze the interaction between the different subsystems. Due to the complexity of the baseline power system and the large number of subsystems, a sample power distribution system, which captures the essential features of the baseline system but is not as complicated, is introduced. The sample power system is represented as a interconnection of a source and load subsystem.
Sample Power Distribution System
The sample power distribution system is shown in Fig. 2. The source subsystem represented by subsystem 1 consists of an ideal three phase voltage source, a three-phase boost rectifier to provide the regulated 270V DC required by the DC bus. The load subsystem represented by Subsystem 2 is an electromechanical actuator used to control the secondary flight control surfaces on the aircraft. The other loads on the DC bus are modeled by a current source, or a simple resistance.
The EMA model shown in Fig. 5 is shown to include a DC motor with constant field, a ball screw transmission between the motor and the control surface, and a model of the surface dynamics. The motor voltage is controlled by a PWM bidirectional buck converter with an input filter. The EMA is controlled by a multi-loop controller, which includes a motor current, motor speed, and the ball screw position feedback loops.All of the other loads on the bus are modeled by a resistor or a current source.
Electro hydrostatic Actuation (EHA)
- In contrast to EMA, EHA (Figure 2) uses fluidic gearing between the electric motor and the surface actuator. Hydraulic fluid provides an intermediate means of transmitting power to the surface. Here, a variable-speed electric motor (typically DC) is used to drive a fixed-displacement hydraulic pump, which in turn, powers a conventional hydraulic piston jack. Change in direction is achieved by the use of a bi-directional motor. A major advantage to this approach is that the EHA operating mode can be managed like a conventional hydraulic actuator. This approach is achieved using standard hydraulic bypass or damping valves (Figure 3); thus traditional active-standby, or active-active, actuator configurations can be readily adopted. This capability makes the EHA more suitable for primary flight control applications than the EMA. Although EHA technology reintroduces hydraulic components and fluid, it is totally self-contained within the actuator assembly. Compared to traditional hydraulic actuator systems, the inconvenience of hydraulic disconnection from aircraft supplies and the complications of bleeding the system during reinstallation are not encountered during maintenance.
Electrohydrostatic Actuators (EHA)
Large EHA
EHA Control Schematic
Benefits of electrically powered Actuators:
The potential benefits of electric actuation at a system level have been well publicized.
Electric actuation can offer:
- Improved aircraft maintainability:
- Fewer hydraulic components are required,
- Faster aircraft turnaround,
- Fewer spares and tools are needed,
- Improved fault-diagnosis through built-in test (BIT).
- Improved system availability and reliability:
- Electrical distribution is more practical and offers system flexibility with respect to reconfiguration Ñ a capability previously difficult to achieve using hydraulics,
- Improved mean-time-between-failures (MTBFs) through removal (electromechanical actuation or EMA) or on-demand usage (electrohydrostatic actuation or EHA) of hydraulic components.
- Improved flight safety Ñ in the MEA configuration, improved system safety is achieved through dissimilar actuator power supplies and subsequent avoidance of common mode failures.
- Reduced system weight Ñ weight saving, achieved through the replacement of entire hydraulic systems, including pumps, distribution networks (pipes and fluid), and valve blocks, by electric systems.
The main benefit is the reduction of aircraft operating costs, for example, reduced fuel cost (as a result of reduced weight), and lower maintenance costs (quicker turnaround). However, before such benefits can be realized, additional work is required to improve the technology and provide the appropriate application platforms to introduce the technology into service.
Furthermore, the aircraft maintenance industry must realign its infrastructure so that it can reap the benefits of electric technologies.
Some additional benefits of both EMA and EHA actuators are:
- Low quiescent power consumption during standby operation,
- Rapid start-up response,
- Can be easily adapted for use with AC or DC electric supplies,
- Insensitive to supply frequency variation of AC electric supplies.
EHA versus EMA?
An alternative to EHAs, are ‘electromechanical actuators’ (EMAs), in which the motor torque is mechanically amplified and transmitted to the control surface using a gear set, screw or other mechanical transmission device, can be seen as an alternative. Indeed, as far as complexity, weight, reliability and maintenance requirement are concerned, EMAs are potentially more attractive than EHAs, at least for low power applications. In particular, all hydraulic technology relevant problems are obviously eliminated from the EHA configuration. However, in the three following areas EHAs are still preferable to EMAs:
?The jamming probability of an EMA used in a primary flight control application is difficult to predict and substantiate from existing in-service experience. Jamming probability of an EHA, can be directly assessed from the current servo control experience, and shown as ‘extremely improbable’ if properly bypassed. In contrast, the jamming probability of mechanical systems incorporating hundreds of gear teeth and screw mechanisms is questionable and present-day experience in secondary flight control applications may not be directly transferable to primary flight controls, due to very different duty cycles in particular
Wear of the mechanical transmissions components may result in control surface ‘free-play’ or other non-linearities, which may generate unacceptable limit cycles
?The introduction of an EHA in parallel with regular servo control in the basic more-electric architecture described above is easier than an EMA. EHAs can easily be made reversible in standby mode, they can incorporate identical damping devices to those currently used for flutter protection, and they can be built with many components common with the adjacent servo control such as the piston, cylinder, associated position transducer or the accumulator. In an obvious move to spread the technical as well as financial risk, Airbus has called on the talents of several companies for the design, production and supply of the many actuators on this mammoth aircraft. Specifically, the A380 aileron and elevator EHAs, as well as rudder EBHAs are purchased from Goodrich, while Messier-Bugatti will supply the associated EHA pumps. Meanwhile, the spoiler EBHAs are from Liebherr, which supplies its own pumps. Phil Hudson, Goodrich VP engineering for actuation systems notes: “The electronic EHA concept can also be designed to serve more functions than simply motor control. It can serve as a smart actuator controller in its own right and be part of a distributed control system or to control a set of multiple actuators. Another benefit is that this distributed technology puts intelligence local to the actuation elements in a control system and can substantially reduce harness weight and improve fault detection and isolation.”
Maintenance benefits are also substantial. Power-by-wire EHA actuation units are line-removable with only mechanical and electrical connections to the aircraft, which eliminates the need to refill or bleed systems of hydraulic fluids as is required with central hydraulics. Since power-by-wire actuators are self contained and remotely located at the surfaces, the area exposed to damage is greatly reduced. Additionally, power-by-wire actuators can be designed as position sensitive, which means that the actuators provide only the flow and pressure necessary to move and hold the actuator in a desired
position. Conventional central-hydraulic systems are configured to produce continuous pressure. Flow is metered at each actuator, which can lead to a large consumption of power and generate unwanted heat. William Schley, R&D supervisor, Parker Aerospace, Controls Systems Division explains that EHAs only consume power on demand. Specifically, they consume power in proportion to the power delivered to the load. In contrast, a conventional EVSV-equipped hydraulic servoactuator consumes power in proportion to output speed, allocating power to output load as needed, with the remainder of the power being dissipated through pressure drop (heat) across the main control valve. Whilst hydraulic actuators become more efficient the more they are loaded, loads are typically low during most of a flight.” Another important advantage of electric actuators is survivability. Ballistic or explosive damage to an electric power distribution system or actuator usually does not cause loss of function of that entire channel, particularly if the damage is peripheral. In a hydraulic system, depending on its design, even a small leak can cause a major loss of function and/or fire. Although some electric actuators contain
hydraulic fluid, the system as a whole is still usually more survivable. For now, these more advanced failure management functions are being provided by the EHA and its variants. EHA combines the best of electric actuation and conventional hydraulics for a hybrid design approach, which is more fault tolerant than most current EMAs. Moreover, EHAs are mechanically simple, and immune to gear train jams. The typical long-term storage capability for EHA is 10 years plus.
Next-Generation---All-Electric Aircraft:
The “All-Electric” aircraft is a concept that emerged in the 1970s and has engendered a large amount of research activity. An all-electric engine, which could replace current aero gas turbines, would drive all accessories electrically, via a distribution network, from motor/generators embedded in the engine spools. Extending the function of the motor/generators to include service as active magnetic bearings would facilitate deletion of the oil system. The all-electric concept thus offers a huge scope for both engine and airframe reconfiguration and operational improvements, with studies indicating benefits of overall weight reduction, increased reliability, easier maintainability, reduced operating costs (including reduced fuel burn), and enhanced safety.
Conclusion:
Beginning with the scenario of a single hydraulic power supply replaced by an electric one, it is possible to establish the relativity and scale for the changes required in the migration toward the “All-Electric” aircraft concept. On a small civil airliner, typically a minimum of five electric actuators would be needed to provide one lane of electrical control for the primary flight control surfaces. If all hydraulic systems were converted to electric, in excess of 20 electric actuators would be needed to provide complete control of all primary and secondary flight control surfaces. The consequential increase in electrical power demand has major implications for electrical power generation and distribution systems. Thus, a significant amount of work is still needed to address the consequences of distributing many electrical actuators around an aircraft, and the consequential start-up, steady state, and peak demands required of aircraft electrical power supplies.
It is clear that the migration to electric actuation systems is affecting both civil and military markets. As described previously, the replacement of a single hydraulic system by an electric substitute is a major step in the transition to all-electric technologies. It is quite evident that the demands being made on aircraft generators and distribution architectures will increase considerably to meet the needs of this migration. A company named TRW has already developed products to meet the current demands envisioned by PBW and has programs to ensure that it will meet any future demands required by the all-electric aircraft. Finally, it is envisioned that once in service, electric actuator technology and electrical system architectures will improve the commercial viability and in-service reliability of the airframes to which they are fitted. These improvements will undoubtedly drive the adoption of greater levels of electric actuation on future aircraft.
References:
- Weimer J. A, “Power management and distribution for the More Electric Aircraft”, Proceedings of the30thIntersocietyEnergyConversion Engineering Conference, vol. 1, July 1995, pp. 273-277
- Technology Review Journal — Millennium Issue • Fall/Winter 2000
- ACTUATOR DEVELOPMENT OVERVIEW
D. Tesar, UT Austin, Robotics Research Group April 1, 2006
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