Download Full Article By-wire-steered system .doc

ABSTRACT

By-wire-steered system is integration of electronic devices and mechanical systems in order to improve the performance of the steering system.
Recent advances in dependable embedded system technology, as well as continuing demand for improved handling and passive and active safety improvements, have led vehicle manufacturers and suppliers to actively pursue development programs in computer-controlled, by-wire subsystems. These subsystems include steer and brake-by-wire, and are composed of mechanically decoupled sets of actuators and controllers connected through multiplexed, in-vehicle computer networks.

A steer-by-wire system replaces the traditional mechanical linkage between the steering wheel and the road wheel actuator (e.g., a rack and pinion steering system) with an electronic connection. This allows flexibility in the packaging and modularity of the design. Since it removes the direct Kinematic relationship between the steering and road wheels, it enables control algorithms to help enhance driver input.There is no mechanical link to the driver. Steer- and brake-by-wire provide a number of packaging and assembly advantages over conventional subsystems. For instance, electromechanical brake-by-wire subsystems require no hydraulic fluid to store or load at the assembly plant and permit more modular assembly, thus reducing the number of parts to be handled during production. Steer-by-wire systems have no steering column and may also eliminate cross-car steering assemblies such as racks. Arguments for ‘by-Wire’ systems include production costs, packaging and traffic safety . The ‘by-Wire’ technology as in drive, brake and steer is gaining ground and is undoubtedly an automotive solution of the future.

The arguments to support such ‘by-Wire’ systems include reduced production costs and packaging advantages and improved traffic safety. Emerging drive-by- wire technologies offer new possibilities for designing the steering characteristics of road vehicles. When the mechanical link between the steering wheel and the front wheels is replaced by sensors, controllers and actuators, enormous flexibility is achieved in terms of the control device applied and in terms of the transfer function of the steering system. This offers new possibilities for optimizing the steering system for mass-produced vehicles. However, the flexibility is of even greater advantage in the area of car adjustment for drivers with physical disabilities.

The transition to purely electrical steering systems will take place step by step via systems with mechanical or hydraulic backup. Development and production of the next generations of electrical steering systems up to purely electrical steering systems create high safety demands on components and systems. Reliable and safe electrical steering systems can be realized by using appropriate safety techniques for these new systems and their components combined with the know-how of safety relevant vehicle systems.

The main limitations of by-wire-steered system are the requirement of a 42 Volts car supply, high output alternator and new generation batteries.The steer-by-wire principle becomes absolutely necessary when Future innovative steering functions, such as vehicle dynamic interventions, collision avoidance, individual wheel steering, tracking assistance, automatic lateral guidance, and finally autonomous driving functions have to be implemented in a system compound of various vehicle systems.

INTRODUCTION

By-wire-steered system is an application of ‘MECHATRONICS’, which is the integration of electronic devices and mechanical systems in order to improve the performance of the system .

Recent advances in dependable embedded system technology, as well as continuing demand for improved handling and passive and active safety improvements, have led vehicle manufacturers and suppliers to actively pursue development programs in computer-controlled, by-wire subsystems. These subsystems include steer and brake-by-wire, and are composed of mechanically decoupled sets of actuators and controllers connected through multiplexed, in-vehicle computer networks. There is no mechanical link to the driver. Steer- and brake-by-wire provide a number of packaging and assembly advantages over conventional subsystems. For instance, electromechanical brake-by-wire subsystems require no hydraulic fluid to store or load at the assembly plant and permit more modular assembly, thus reducing the number of parts to be handled during production. Steer-by-wire systems have no steering column and may also eliminate cross-car steering assemblies such as racks. Arguments for ‘by-Wire’ systems include production costs, packaging and traffic safety

The ‘by-Wire’ technology as in drive, brake and steer is gaining ground and is undoubtedly an automotive solution of the future. The arguments to support such ‘by-Wire’ systems include reduced production costs and packaging advantages and improved traffic safety (a boon for everybody involved). Emerging drive-by- wire technologies offer new possibilities for designing the steering characteristics of road vehicles. When the mechanical link between the steering wheel and the front wheels is replaced by sensors, controllers and actuators, enormous flexibility is achieved in terms of the control device applied and in terms of the transfer function of the steering system. This offers new possibilities for optimizing the steering system for mass-produced vehicles. However, the flexibility is of even greater advantage in the area of car adjustment for drivers with physical disabilities.

A steer-by-wire system replaces the traditional mechanical linkage between the steering wheel and the road wheel actuator (e.g., a rack and pinion steering system) with an electronic connection. This allows flexibility in the packaging and modularity of the design. Since it removes the direct
Kinematic relationship between the steering and road wheels, it enables control algorithms to help enhance driver input.
The transition to purely electrical steering systems will take place step by step via systems with mechanical or hydraulic backup. Development and production of the next generations of electrical steering systems up to purely electrical steering systems create high safety demands on components and systems. Reliable and safe electrical steering systems can be realized by using appropriate safety techniques for these new systems and their components combined with the know-how of safety relevant vehicle systems.

‘Steer-by-Wire’ (SbW) there exists a legislation obstacle as European regulations require a mechanical connection between the steering wheel and the wheels. The column electric power steering (C-EPS) in the Opel Astra is therefore only an electric hybridization at steering level: the steering torque levels will increase when the car picks up speed. The “Dual drive” system in the Fiat Punto has an EPS with dual settings: the driver can activate the “city” mode and obtain gentler steering when parking. The main limitations of by-wire-steered system are the requirement of a 42 Volts car supply, high output alternator and new generation batteries.
The steer-by-wire principle becomes absolutely necessary when Future innovative steering functions, such as vehicle dynamic interventions, collision avoidance, individual wheel steering, tracking assistance, automatic lateral guidance, and finally autonomous driving functions have to be implemented in a system compound of various vehicle systems.

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Download Full Article pro-logic-ii.DOC

ABSTRACT

Pro Logic II, the next generation of Dolby Surround Pro Logic decoding technology. Pro Logic II brings exciting new features and advanced performance for decoding the many thousands of existing Dolby Surround programs, making them sound more like a discrete Dolby Digital 5.1-channel version than ever before.

The world is rapidly transitioning to digital delivery formats like DVD, and digital television (DTV), satellite and cable, all of which offer Dolby Digital 5.1 audio capability. The music industry is on the verge of transitioning from stereo to 5.1-channel sound with the new DVD-Audio format. Consumers enthusiastically demand 5.1-channel sound in new programs of all kinds. But vast numbers of programs already exist in stereo and Dolby Surround, and many more will continue to arrive in years to come. Pro Logic ­II lets consumers enjoy these programs with a convincing io5.1-likelc presentation.

Pro Logic II is able to decode the thousands of existing Dolby Surround movies and TV shows already on the shelf, compatibly, and with enhanced image stability. The improvements in decoding techniques mean that the discreteness of the sound field elements are better-preserved in the decoding process than was possible with the now universally standard Pro Logic technology, developed in the mid 80s.

“The technology in Pro Logic II is the first fundamentally new approach in matrix decoder design since the basic design which is still at the core of every other active matrix surround decoder” said Roger Dressler, Director of Technology Strategy for Dolby Laboratories. “Pro Logic II was designed from the outset to convert conventional stereo music recordings, which will be with us for some time to come, to a natural, believable surround experience. The result is a decoder that can handle a wide range of movie and music program material with equal skill. Dolby is proud to be handling the licensing and technical support of this exciting new technology”

This new system was invented by Jim Fosgate, one of the most prolific developers of surround decoding technologies since the quadraphonic era of the late 1960s. Mr. Fosgate said,” I have spent the past 25 years figuring out how to expose the hidden information in standard two-channel stereo recordings, both new and old. This breakthrough in matrix decoding technology allows users to enjoy all their existing two-channel programs, whether Dolby Surround encoded or not, with an enhanced level of spatiality and directionality.”

Pro Logic II also incorporates special features for controlling the overall spatial dimensionality and frontal sound field imaging that are particularly suited for auto sound applications. A standard four-channel Pro Logic decoding mode is also included in the technology package.

Dolby Surround Pro Logic II decoding can be implemented economically in either analog or digital circuitry, making it ideal for use in all traditional home theater products and in a range of new “music surround” products…………..

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Download Full Article Air Muscles.pdf

ABSTRACT

Air muscle is essentially a robotic actuator which is replacing the conventional pneumatic cylinders at a rapid pace. Due to their low production costs and very high power to weight ratio, as high as 400:1, the preference for Air Muscles is increasing. Air Muscles find huge applications in biorobotics and development of fully functional prosthetic limbs, having superior controlling as well as functional capabilities compared with the current models. This paper discusses Air Muscles in general, their construction, and principle of operation, operational characteristics and applications.

INTRODUCTION

Robotic actuators conventionally are pneumatic or hydraulic devices. They have many inherent disadvantages like low operational flexibility, high safety requirements, and high cost operational as well as constructional etc. The search for an actuator which would satisfy all these requirements ended in Air Muscles. They are easy to manufacture, low cost and can be integrated with human operations without any large scale safety requirements. Further more they offer extremely high power to weight ratio of about 400:1. As a comparison electric motors only offer a power ration of 16:1. Air Muscles are also called McKibben actuators named after the researcher who developed it.

History

It was in 1958 that R.H.Gaylord invented a pneumatic actuator which’s original applications included a door opening arrangement and an industrial hoist. Later in 1959 Joseph.L.McKibben developed Air Muscles. The source of inspiration was the human muscle itself, which would swell when a force has to be applied. They were developed for use as an orthotic appliance for polio patients. Clinical trials were realized in 1960s. These muscles were actually made from pure rubber latex, covered by a double helical weave (braid) which would contract when expanded radially. This could actually be considered as a biorobotic actuator as it operates almost similar to a biological muscle.

Air Muscle Schematic- McKibben Model

The current form air muscles were developed by the Bridgestone Company, famous for its tires. The primary material was rubber i.e. the inner tube was made from rubber. Hence these actuators were called ‘Rubbertuators’. These developments took place around 1980s.
Later in 1990s Shadow Robotic Company of the United Kingdom began developing Air Muscles. These are the most commonly used air muscles now and are associated with almost all humanoid robotic applications which were developed recently. Apart from Shadow another company called The Merlin Humaniform develops air muscles for the same applications, although their design is somewhat different from the Shadow muscles.

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Download Full Article Electro-Mechanical Brake.pdf

ABSTRACT

Brake performance can be divided into two distinct classes:
1) Base brake performance
2) Controlled brake performance.
A base brake event can be described as a normal or typical stop in which the driver maintains the vehicle in its intended direction at a controlled deceleration level that does not closely approach wheel lock. All other braking events where additional intervention may be necessary, such as wheel brake pressure control to prevent lock-up, application of a wheel brake to transfer torque across an open differential, or application of an induced torque to one or two selected wheels to correct an under- or over steering condition, may be classified as controlled brake performance. Statistics from the field indicate the majority of braking events stem from base brake applications and as such can be classified as the single most important function. From this perspective, it can be of interest to compare modern-day Electro-Hydraulic Brake (EHB) hydraulic systems with a conventional vacuum-boosted brake apply system and note the various design options used to achieve performance and reliability objectives.

INTRODUCTION

What is an EHB System?

The next brake concept. This system is a system which senses the driver’s will of braking through the pedal simulator and controls the braking pressures to each wheels. The system is also a hydraulic Brake by Wire system

Many of the vehicle sub-systems in today’s modern vehicles are being converted into “by-wire” type systems. This normally implies a function, which in the past was activated directly through a purely mechanical device, is now implemented through electro-mechanical means by way of signal transfer to and from an Electronic Control Unit. Optionally, the ECU may apply additional “intelligence” based upon input from other sensors outside of the driver’s influence. Electro-Hydraulic Brake is not a true “by-wire” system with the thought process that the physical wires do not extend all the way to the wheel brakes. However, in the true sense of the definition, any EHB vehicle may be braked with an electrical “joystick” completely independent of the traditional brake pedal. It just so happens that hydraulic fluid is used to transmit energy from the actuator to the wheel brakes. This configuration offers the distinct advantage that the current production wheel brakes may be maintained while an integral, manually applied, hydraulic failsafe backup system may be directly incorporated in the EHB system. The cost and complexity of this approach typically compares favorably to an Electro-Mechanical Brake (EMB) system, which requires significant investment in vehicle electrical failsafe architecture, with some needing a 42 volt power source. Therefore, EHB may be classified a “stepping stone” technology to full Electro-Mechanical Brakes.

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