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4. Embedded Controls

4.1 Smart Sensors and Actuators

The general internal structure of a smart control

Transceiver

Control Logic

Sensor/Actuator HW

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Transceiver

A transceiver component connects the device with network. It handles the low level protocols for data transfer.

Control Logic

The control logic is usually a microprocessor that provides the actual intelligence in the device.

It intercepts the commands from the network, processes them, and sends out the appropriate response.

Sensor / actuator hardware

The sensor / actuator hardware either senses its environment or activates motors, solenoids, and the like to carry out an action.

Sensors are available for air temperature, liquid temperature, pressure, and to detect various gasses.

Actuators are sometimes just controlled electrical switches that are used for switching lights and appliances on and off.

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Example: A simple network for external lighting control

AmbientLight

Sensor

PresenceSensor

SecurityController

LightingActuator

Twisted Pair/

Power Line

The controller checks the ambient light level to determine when it is dark to activate the lighting.

It also checks the external proximity sensor to determine if a person approaches the building. If someone approaches the building when it is dark outside, the lighting controller turns on the outside lights.

A network of controls communicating with each other over power line. How are the controls addressed in the network?

How will network configuration be performed? In other words, how will the controllers “find” the sensors and actuators?

What about security – if power line networking is used, will the neighbor be able to turn on my lights?

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Control Networks or Home Networks

Control networking concerns itself with communication between smart sensor, actuactors, and controllers in general.

For connecting sensors and actuators in a residential setting, power line networking is often used.

The address is composed of two portions: the house address and the unit address. If the user notices interference, the house address portion must be changed on all controls.

Wiring with a Home Network, p. 71

The controls could be dynamically reprogrammed to implement specific behavior.

Ex) An “on vacation” function could note typical lighting patterns while the family is at home and then simulate these patterns when the family is on vacation.

Security is another important element of control networking.

A Residential Gateway, p. 72

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4.2 Smart Appliances

Smart appliance – devices used to increase comfort or convenience that are endowed with a certain computer intelligence and networking capability.

4.2.1 The Smart Clock

One very useful smart appliance will be the smart clock. A clock will become a provider of time services in the home network.

4.2.2 Heating, Ventilation, and Air Conditioning

There are usage patterns for each room in a home. The heating system could adapt itself to these patterns using information from the room thermostats and from the other devices in the room.

Power management is another appliance of smart devices.

In a time of need, the power company might send signals over the power line to turn the air conditioner off for ten minutes out of each hour in all homes in a round-robin fashion.

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4.2.3 White Goods Appliances

e-Maintenance

Savings can be achieved through remote service or remote diagnosis.

Article Awareness

If we imagine a time when smart labels are in prevalent use in product packaging, additional possibilities in for the automated home arise.

A washing machine could contain a smart label reader in order to be aware of the type and required washing machine program for each article of clothing put into the drum.

Remote Access and Operation

Web-capable appliances will allow access through the Internet or through a telephone.

Remote access is also an implementing function for commercial use.

Real-World Smart Appliance

Web-enabled household appliances (Merloni Elettrodomestici Co.)

Merloni Margerita2000, one of the world’s first digitally enabled washing machines.

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The machine is a member of the Ariston Digital line of network capable appliances.

The Margherita2000 can accept commands or display operating status through a cellular phone or through the Internet.

The Telelink uses either a standard analog modem or a GSM cell phone modem for communication external to the home and uses power line networking techniques for communication with other Ariston Digital appliances.

Services offered through the Telelink vary by appliance, and include remote diagnostic, customer support, and power management services.

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4.3 Appliance and Home Networking

4.3.1 Residential Gateway

Residential Gateway

Networked Appliances, p. 79

The consumer would address the residential gateway, authenticate herself, and then communicate with the intended appliance.

Cellular Communication

Cellular Communication with appliances, p. 80

The consumer would browse the web site of a service provider, who would dial up the refrigerator and obtain the requested information.

Service Provider and Residential Gateway

Service Provider and Gateway, p. 81

The “home network” service provider would actually be responsible for the the setup and operation of the residential gateway.

It would have a security as well as a routing function.

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4.4 Automotive Computing

Intelligent Controls, Sensors, and Actuators

Controllers, computers, and in-vehicle networks collaborate to make driving easier, safer, and more comfortable.

Sensors are detecting all possible parameters, like rainfall, pressure in the tires, or intensity of sunshine.

OSEK(Open Systems and the Corresponding Interfaces for Automotive Electronics) has been specified by European automobile manufacturers as a standard operating system platform for embedded controllers.

OSEK includes communication protocols and network management for automotive environments.

On-Board Computing Systems

Navigation Systems

• GPS(Global Positioning System)

Telematic

• Dynamic navigation is a telematic application complementing simple navigation by retrieving up-to-date travel information from a content provider.

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• 자동차 텔레매틱스 서비스는 이동통신기술과 위치추적기술을 자동차에 접목하여 차량사고나 도난감지 , 운전경로 안내 , 교통 및 생활정보 , 게임 등을 운전자에게 실시간으로 제공한다 .

The navigation system can retrieve relevant traffic information in different ways:

• TMC(Traffic Message Channel)

• SMS(Short Message Service)

• WAP(Wireless Application Protocol)

Traffic jam sensors

FCD(Floating Car Data)

• Informs the travel information center in regular intervals about the position and the speed of the car.

Infotainment

• Soon data, video, and audio streams will be delivered via high-bandwidth wireless links to the driver to provide travel-related content as well as e-commerce capabilities, games, and movies.

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• Multimedia usage in vehicles implies new requirements to human computer interfaces in order to allow hands-free and eyes-free operation of the devices while driving.

• Voice recognition

• TTS(Text-To-Speech)

Automotive Computer Systems

• High-end automotive application platforms: Microsoft Windows CE-based Auto PC, Motorola Mobile GT Architecture

• Mobile GT is based on a PowerPC processor running the QNX real time operating system. Applications are written in Java and execute on an IBM Java Virtual machine.

• Motorola’s Mobile GT Architecture, p. 88

In-Vehicle networks

As the usage of interconnected electronic sensors, controllers, and devices increased, the automotive industry faced three problems.

• Increased the weight of the car, increased the complexity of assembly, and become too expensive

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• Complexity and dependencies made development more difficult.

• Its electronics cost more and have fewer features than comparable products on the market.

Generic bus systems – the benefits of a vehicle bus system

• Instead of complex, peer-to-peer wiring, each component is plugged into the in-vehicle network.

• Components have well-defined interfaces to the bus.

• Due to the common interface, components can be developed independently from the car itself.

J1850 and ODB-II

• The Society of Automotive Engineers (SAE)

• With J1850, only limited interoperability was achieved, since the specification allowed the manufacturer to implement it in multiple proprietary ways.

• The Onboard Diagnostics (OBD-II) interface can also be used to provide a standardized access to some of the internal electronic systems.

Controller Area Network

• The European automotive industry adopted the CAN, which now gains worldwide acceptance as the common technology for the mission critical networks.

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• Communication is based on message broadcast by a node onto the bus.

• This message-triggered approach allows priority to be assigned to each message type.

• Message format

identifier Length of data field

Message(CRC, ACK, EOF) Intermission

Local Interconnect Network

• LIN also allows implementation of hierarchical vehicle networks. Smart sensors, motors, panels, and actuators can be connected to a local LIN sub-network.

• Communication between the sub-network and an in-vehicle CAN bus is carried out through a gateway.

• LIN is an open standard driven by Audi, BMW, DaimlerChrysler, Motorola, VCT, VW, and Volvo.The specification includes the transmission protocol, the physical layer of the transmission, and software programming interfaces.

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• Typical In-vehicle Network

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IDB-Bus

• Three industry initiatives are working together to define the next generation of automotive bus system.

• Intelligent Transportation Systems Data Bus (IDB) Forum

o IDB-T(IDB for Telematics)

o The specification of a plug-and-play mechanism for devices connected to the IDB-C bus is in progress.

o A 100 Mbps bus called IDB-Multimedia (IDB-M) is the nest challenge for the IDB Forum. As audio and video streams need to be supported by the in-vehicle networks, there is a demand for high-bandwidth connections based on an optical carrier.

• The Automotive Multimedia Interface Collaboration (AMIC) specifies programming and hardware interfaces for the IDB OEM gateway.

o “developing a set of common specifications for a multimedia interface to motor vehicle electronic devices in the vehicle”

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• IDB Technology

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• The AMIC specification base on the IDB-C bus technology and target:

- simple devices (like sensors, actuators, switches, and displays)

- controllers running dedicated tasks (like radio, navigation systems, and embedded processors)

- hosts systems running user application (like an Auto PC)