magic body control

BANSILAL RAMNATH AGARWAL CHARITABLE TRUST`S

VISHWAKARMA INSTITUTE OF TECHNOLOGY PUNE-37 (An Autonomous Institute Affiliated to University of Pune)

A seminar report on “SELFHEALING POLYMER TECHNOLOGY” Submitted By

ATUL K. SHINDE ( TE-V_01 ) Under The Guidance of

Prof. M.V.WALAME

Department of Mechanical Engineering 2014-2015

BANSILAL RAMNATH AGARWAL CHARITABLE TRUST`S

VISHWAKARMA INSTITUTE OF TECHNOLOGY PUNE-411 037

(An Autonomous Institute Affiliated to University of Pune.)

CERTIFICATE This is to certify that the Seminar titled “SELF-HEALING POLYMER TECHNOLOGY” has been completed in the academic year 2014 – 2015, by Mr. ATUL K. SHINDE in partial fulfillment of Bachelor’s Degree in Mechanical Engineering as prescribed.

PROF. M.V.WALAME (Guide)

Place : Pune Date :

PROF. H.G.PHAKATKAR (H.O.D. - Mechanical Dept.)

Examiner

MAGIC BODY CONTROL

ABSTRACT Mercedes-Benz is defining a level of ride comfort with Magic Body Control, the world’s first suspension system with “eyes”. Magic body control combines the advantages of the active suspension system active body control (ABC) with the globally innovative road surface scan function - a stereo camera that scans the road ahead and registers the road surface and its condition.Premiered in 2013 in the flagship S-Class, this pioneering technology features a highly-sensitive sensor system that scans the road ahead for bumps or potholes and then adjusts the car’s suspension accordingly. Magic Body Control is the next generation of Active Body Control. Created with the help of ZF, the system of bushings atop the strut towers neutralizes wheel and body movements at two different frequencies. Daimler's testing indicates that MBC reduces 80 percent of unsavory suspension reverberations. It will show up on the S-Class and CLClass.

INTRODUCTION

Mercedes-Benz is presenting a new innovation in the new S-class, the world’s first car capable of detecting road surface undulations in advance. Mercedes' current ABC system uses a hydraulic piston to act on each steel coil spring to quickly and independently adjust the suspension on each wheel in reaction to the road surface, and it does a fine job keeping the ride smooth and occupants unjostled. But the key term there is “reaction”—the suspension deals with the bumps after the wheel has encountered them. What if the car knew what was coming in advance, with absolute certainty and down to every imperfection? The oil flow at each corner could be adjusted so accurately that any surface flaw could be practically neutralized. That's exactly what Magic Body Control intends to do. A camera situated at the top of the windshield scans the road ahead, analyzing its flaws and blemishes, and feeds that data directly to the ABC system's control unit. The camera scans the area 15 to 45 feet in front of the car, and it can detect and measure imperfections as small as 0.4 to 0.8 inch. In doing so, the system knows exactly what the tires will encounter just fractions of a second into the future. The series-production use of a camera to gather road data is different from the laser-based approach used on the F700 concept, where the technology was called pre-scan. The camera also feeds information to the distronic cruise control. Mercedes launched their magic body control in 2013 which will be seen in new S-class and CL-class.

SUSPENSION

Suspension is the system of springs, shock absobers and linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems serve a dual purpose — contributing to the vehicle's road holding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations,etc. These goals are generally at odds, so the tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the road or ground forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different. SUSPENSION IN MAGIC BODY CONTROL Magic Body Control is based on the ABC(Active Body Control) suspension featuring active suspension which improves both comfort and driving dynamics.

ACTIVE SUSPENSION

The active suspension and adaptive suspension/semi-active suspension are types of automotive suspensions that controls the vertical movement of the wheels relative to the chassis or vehicle body with an onboard system, rather than in passive suspensions where the movement is being determined entirely by the road surface. Active suspensions can be generally divided into two main classes: pure active suspensions and adaptive/semi-active suspensions. While adaptive suspensions only vary shock absorber firmness to match changing road or dynamic conditions, active suspensions uses some type of actuator to literally raise and lower the chassis independently at each wheel.

These technologies allow car manufacturers to achieve a greater degree of ride quality and car handling by keeping the tires perpendicular to the road in corners, allowing better traction and control. An onboard computer detects body movement from sensors throughout the vehicle and, using data calculated by opportune control techniques, controls the action of the active and semi-active suspensions. The system virtually eliminates body roll and pitch variation in many driving situations including cornering, accelerating, and braking.

HYDRAULIC ACTUATED .

Hydraulically actuated suspensions are controlled with the use of hydraulic servomechanisms. The hydraulic pressure to the servos is supplied by a high pressure radial piston hydraulic pump. Sensors continually monitor body movement and vehicle ride level, constantly supplying the computer with new data. As the computer receives and processes data, it operates the hydraulic servos, mounted beside each wheel. Almost instantly, the servo-regulated suspension generates counter forces to body lean, dive, and squat during driving maneuvers. In practice, the system has always incorporated the desirable self-leveling suspension and height adjustable suspension features, with the latter now tied to vehicle speed for improved aerodynamic performance, as the vehicle lowers itself at high speed Computer Active Technology Suspension (CATS) co-ordinates the best possible balance between ride quality and handling by analyzing road conditions and making up to 3,000 adjustments every second to the suspension settings via electronically controlled dampers.

MAGIC BODY CONTROL

MAGIC BODY CONTROL is based on the ABC (Active Body Control) suspension featuring active suspension which improves both comfort and driving dynamics. Magic body control combines the advantages of the active suspension system Active Body Control (ABC) with the globally innovative road surface scan function – a stereo camera that scans the road ahead and registers the road surface and its condition. The system is thus able to recognize an uneven road surface before you come to drive over it, thus enabling the suspension to adjust itself in order to counteract, as far as possible, the undulations in the road. Magic body control ensures a unique synthesis of comfort and agility. Regardless of whether the surface of the road you are driving on is smooth or damaged: you glide quietly and serenely over the asphalt.

The basis of the new system is provided by the Active Body Control (ABC) active suspension, which works to hold the vehicle body steady. It can actively regulate the suspension strut forces – and does so for each wheel separately. This dampens the vibrations of your car, while bodywork oscillations caused during steering, braking or accelerating can be almost completely eliminated. This technology is also able to hold your car in its lane much better in critical wind conditions.

The suspension also recognizes the car's load and adjusts its level accordingly. Depending on circumstances, the ground clearance can be increased by up to 40 mm - for example in wintery road conditions. Complementing this system is the new road surface scan function. A stereo camera positioned at about the height of the interior mirror measures the road surface ahead of you and sends the data recorded to the control unit for the suspension, where they are evaluated. The active suspension then takes just fractions of a second to adjust itself to the condition of the road. The result is very agile, precise and yet still comfortable handling, on an apparently ultra-smooth road surface.

WORKING

It starts with analyzing the prevailing driving situation. In order to assess the prevailing driving situation, a microprocessor analyses the signals from the lateral, longitudinal and vertical acceleration sensors and from the pressure sensors assigned to each spring strut. The level of the body is determined by the level sensors on the control arms of the front and rear axles. The four spring struts are fitted with hydraulic cylinders to enable the

force in each spring strut to be adjusted individually. As a result, the vertical, rolling and pitching movements to which the body can be subjected are almost completely compensated for. The control unit receives information on the current driving conditions from various acceleration sensors and compares it with the data from the pressure sensors in the spring strut and the level sensors on the control arms. Subsequently the system calculates control signals for the servo-hydraulic valves on the front and rear axle, in order to meter the flow of oil appropriately. The engines pressure supply system provides the servohydraulic valves with hydraulic pressure of up o 200 bar. The constantly available pressure and the employed accumulators enable active body control to respond to initial signs of body movement in a fraction of second.

Together with the information on the driving conditions, the control unit continually calculates the best control strategy for dealing with unevenness in the road. Based on this, the active suspension is able to make damping harsher or softer within fractions of a second in advance and individually for each separate wheel, and increase or decrease the load on each wheel via the active hydraulics.

ACTIVE BODY CONTROL Active Body Control, or ABC, is the Mercedes-Benz brand name used to describe fully Active suspension, that allows control of the vehicle body motions and therefore virtually

eliminates body

roll in

many

driving

situations

including cornering, accelerating, and braking. In the ABC system, a computer detects body movement from sensors located throughout the vehicle, and controls the action of the active suspension with the use of hydraulic servomechanisms. The hydraulic pressure to the servos is supplied by a high pressure radial piston hydraulic pump. A total of 13 sensors continually monitor body movement and vehicle level and supply the ABC controller with new data every ten milliseconds. Four level sensors, one at each wheel measure the ride level of the vehicle, three accelerometers measure the vertical body acceleration, one acceleration sensor measures the longitudinal and one sensor the transverse body acceleration. At each hydraulic cylinder, a pressure sensor monitors the hydraulic pressure. As the ABC controller receives and processes data, it operates four hydraulic servos, each mounted in series on a spring strut, beside each wheel. Almost instantaneously, the servo regulated suspension generates counter forces to body lean, dive and squat during various driving maneuvers. A suspension strut, consisting of a steel coil spring and a shock absorber are connected in

parallel, as well as a hydraulically controlled adjusting cylinder, are located between the vehicle body and wheel. These components adjust the cylinder in the direction of the suspension strut, and change the suspension length. This creates a force which acts on the suspension and dampening of the vehicle in the frequency range up to five hertz. The system also incorporates height adjustable suspension, which in this case lowers the vehicle up to 11 mm (0.43 in) between the speeds of 60–160 km/h (37–99 mph) for better aerodynamics, fuel consumption, and handling.

The ABC system also allows self leveling suspension, which raises or lowers the vehicle in response to changing load (i.e. the loading or unloading of passengers or cargo). Each vehicle equipped with ABC has an “ABC Sport” button that allows the driver to adjust the suspension range for different driving style preferences. This feature allows the driver to adjust the suspension to maintain a more level ride in more demanding driving conditions. The first complete and ready-for-production version of ABC was introduced in 1999 on the top-of-the-line Mercedes-Benz CL class, the Mercedes-Benz CL112 of 1991 however already featured a prototype version of ABC.

COMFORT AND SPORT MODE At the touch of a button: individual suspension and transmission characteristics The new CL-Class features an S/C/M button in the centre console with which the driver is able to modify the overall characteristics of the coupe from comfortable to sporty: Comfort: In this mode the automatic transmission changes the gears at lower engine speeds, and the CL coupe moves off in second gear. The ABC suspension operates in Comfort mode, comfortably smoothing out uneven road surfaces and bumps. Sport: The automatic transmission makes full use of the engine speed range in this setting. The ABC suspension operates in Sport mode as well, with a stiffer damping effect on uneven surfaces and bumps. The characteristic map of the accelerator is also modified, so that the engine responds more rapidly when acceleration is required. Manual: The automatic transmission is operated manually using gearshift buttons on the steering wheel, with significantly reduced gearshift times compared to the Sport mode. The suspension configuration selected by Active Body Control is the same as in Sport mode, as is the characteristic map of the accelerator.

If the CL-Class is travelling on poor roads which make a higher ground clearance advisable, the driver is able to raise the suspension by 45 millimetres at the touch of a button. When travelling at high speed in Sport mode, ABC automatically lowers the suspension by up to ten millimetres to reduce aerodynamic drag and lower the fuel consumption.

ROAD SURFACE SCAN

ROAD SURFACE SCAN uses a stereo camera positioned behind the windscreen. "It measures the road up to 15 m in front of the vehicle and with a height measurement accuracy of more than around 3 mm". This provides a precise picture of the road surface profile. Together with the information on the driving conditions, the control unit continually calculates the best control strategy for dealing with unevenness in the road. Based on this, the active suspension is able to make the damping harsher or softer within fractions of a second in advance and individually for each separate wheel, and increase or decrease the load on each wheel via the active hydraulics. This can help to reduce vehicle body movements significantly. Since ROAD SURFACE SCAN is a camera-based system, it is able to function during the day in conditions of good visibility and on suitably surfaced roads as well as at speeds up to 130 km/h.

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DISADVANTAGES

Yet this brand of Magic has its limitations: it only works during the day, foul weather can cause the system to pack up (if the camera gets blocked by snow, for instance) and it's really most effective over large disturbances like the aforementioned speed bump, as it's not yet quick-witted enough to catch subtler potholes and such. Oddly, it also only works with ABC set to Comfort Mode – if you choose Sport you're on your own. Most of the time, the system feels like a conventional luxury car, which is to say very well behaved, but not entirely sporty.