Tracing the development history of automated control ...

Tracing the development history of automated control systems used in contemporary F1 carsMartin S Jones August 8th 2017

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Synopsis:

1. Overview of automated ‘driver aids’ in Formula 1 today.

2. Why hydraulic technolgy is selected for these applications

3. Roots of this technology in Automotive R&D in the 50s & 60s.

4. The ‘Lotus Era’ –active suspension and other active sytems.

5. Early adoption these systems in other Motorsport series.

6. The future of automation in Motorsport and it’s relevance to tomorrow’s road cars

7. Transfer of these technologies to other industries

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1. Review of automated actuation systems in Formula 1 today.

Formula 1 applications:in 2017

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2. Why is hydraulic technology used in Formula 1 today ?

Surely hydraulics is 18th Century technology ?

Hydraulics is often dismissed as an outmoded technology with associations with the Victorian period…

The image below shows a hydraulic system installed in London that was operationalfrom 1894-1973 !

Any ideas of what this is ?

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The real answer lies in the Motorsport’s obsession for small size and light weight.Even with recent developments in exotic magnetic materials and electronics, hydraulics hasunparalleled ‘Power density’ compared with electric actuation.

Compare the size of a 3kW a contemporary rare-earth magnet servomotor and the hydraulic servovalve valve of equivalent power.

This doesn’t take into account the ancillary equipment that’s needed – which accentuates the difference.

The secret : Power Density.

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Hydraulics is perfectly suited to multi-axis applications;

A second factor is the large number of actuators on a Formula 1 car, which can share a common hydraulic supply. Effectively the car has an integral ‘Hydraulic ring-main’ installed onto which additional actuatorscan be added with ease.

Some weird features of a typical F1 hydraulic system :

• The hydraulic reservoir can have a capacity of as little as 50 cc.

• The operating temperature can be greater than 130 deg C

• The 110 deg engine water/coolant is often used as the cooling medium for the oil !

• The return line is pressurised at circa 4 Bar to prevent pump cavitation.

• The oil is typically filtered with a 3 micron Beta 200 filter- a necessary requirement of the miniature components


Bill Milliken was head of Flight Research at the Cornell Lab in the late 40s / early 50s . He and his colleagues were instrumental in the design and development of the modern generation of Aircraft controls.A key breakthrough was the ‘variable stability aircraft’ which allowed

the aircraft’s handling characteristics to be changed electronically.


In 1954 a Buick was equipped with avariable feel steering system –what

today would be called Haptics technology.The block diagram on the right shows the‘driver in the loop’ block being used in the analysis with it’s attendant human response & phase lag.

3. Roots of the technology in Automotive R&D in the 50s & 60s.

-An ‘enabler’: -the recently invented ‘Moog Valve’.

In 1951 Bill Moog introduced the first high-resolutionelectro-hydraulic servovalve which had sufficient precisionfor sucessful control of the steering feel.

Critically, this valve used the power of the hydraulic system to amplify the electrical valve comand signal via a ‘Torque Motor’ and hydraulic bridge, eliminating the need for a high power electrical signal .

Max Movement of armature ±0.075 mm

Electrical Current

Torque motor

Air gap 0.125-0.300mm

NozzleFlapper

Feedback wireOrifice

Ø 0.15-0.4 mm

0.0015-0.0025 mm(1.5-2.5 µm)

Null Cut

Load∆ PL Spool

Ø 3.8 mm

Spool bushing fit

(1.5-3.0 µm)0.0015-0.003 mm

0.2-0.5 mmSpool Stroke

Drain Orifice

Ø 0.17 mm


Moog Valve:Principle of operation


The current evolution of Bill Moog’s original valve

Over 60 years on the latest iteration of Bill’s invention has some impressive statistics:

• It weighs just 92gm yet can control hydraulic powers of up to 3.2 kW.• It can withstand ambient temperatures of 165 deg C and 50 g vibraton.• The electrical control input is just 38 mW with duplex redundancy for reliability.• It has a bandwidth of 280Hz and an repeatability of just 1%.

OutputFlow

Input Current


In 1956 a full aircraft type ‘steer by wire’system was Installed in a Buick,

allowing variable control of the steering ratio and the ‘weight’ of thesteering for the driver.This was a valuable analytical tool foroptimising steering and other chassisDevelopments.Incredibly, the car was driven on thehighway from Buffalo to Detroit for

various demonstrations.


This interior shot of the ‘fly by wire’ car shows the complicated ‘ user interface’ -used to program the system. The electronics incorporated some very early transistor technology

4. The ‘Lotus Era’ –active suspension and other sytems.

The Lotus 92 F1 car:

Team Lotus pioneered the use of high pressure hydraulics in F1 in the Lotus 92 of 1983, which utilised fully ‘active’ suspension.

This radical design dispensed entirely with springs and dampers, relying entirely on a high-response hydraulic servo-system to provide both springing and damping.

In addition it was able to control pitch and roll characteristics of the vehicle.

4. The ‘Lotus Era’:

Early active hydro-mechanical system -from the mid 1980’s

This detail clearly shows the controlprinciple of this approach, namelya hydraulic diverter spool actuatedby means of an inertial mass suspended on a spring.

4. The ‘Lotus Era’:

Active hydro-mechanical system From the late 1980’s

A block scheme of the complete hydro-mechanical system as tested by Williams F1 in the mid 1980’s.A limitation of this approach is the difficulty of filtering out high frequency road inputs .Because of this they later adopted a design utilising Moog Servovalve driven by electronics providing filtering and shaping in addition to loop closure.Feed-forward from the steering was also incorporated to improve the system response

4. The ‘Lotus Era’ –active suspension and other sytems:

Williams Active suspension late 1980’s:

This early hydraulic manifold sketch shows the three Moog E050 valves used in the early ‘ Milking Stool’ principle of active ride height system.

This utilises a single hydraulic actuator and mono-shock arrangement to control front ride height (-with front roll stiffness adjusted mechanically)

Visible are the 4 pressure transducers, filter housing and solenoid for control of system pressure.


Williams FW14B

By the early 1990’s the F1 teams used the integrated hydraulic system in the car - for numerous computer-controlled systems on the car ..

However in 1993 the FIA banned a number of systems including :

• Active suspension• Power assisted and ABS braking• Power Steering


Road Cars


Road Cars

In the early 1980’s, the Lotus organisation also developed sophisticated active suspension systems for road cars. These achieved the previously incompatible characteristics of a compliant ride and excellent handling.

Active and passive Lotus cars shown above during testing in similar conditions on the Hethel test track at the Lotus HQ.

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5. Early adoption of other systems in Motorsport

LMP1 Prototypes:

Actuation systems very similar to F1,but slightly lessRestrictive regulations.


Inlet trumpet actuator under dynamic test

InletTract Length

5. Early adoption of other systems in Motorsport:

RackAssistanceCylinders

Variable orifice to adjust assistance

P

RMOOG E243Power steering valve

Link

Servo steering without electronics:

An interesting example of Motorsport regulations driving unconventional technology

Compliant pinion mounting and linear bearing to give ±0.5mm stroke for full driver input torque


Pressure vs driver input torque Flow vs driver input torque

Non-linear flow-slots can be used instead of a software look-up table

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Semi-automatic gearshifting – using a ratchet operated gearbox drum

Waiting for shift command System response to up-shift command

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‘Fly-by wire’ braking system for hybrid race cars-Automatically modulating rear brake torque in response to electrical braking torque

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The Indycar experiment in the early 1990’s

To circumvent the ‘no electronics’ rules – a purely mechanical active ride-height system was developed in the early 90’s which used linkages springs and dampers to replicate the function of the closed loop systems in an F 1 car.

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WRC Rally Cars:

In the mid 1990’s F1 style hydraulic technology was first adopted by the WRC teams.

The compromise between weight and robustness was different to F1 because of the hash operating conditions which spawned new hydraulic developments.


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• Very robust valve doesn’t require fine filtration, long service life.

• Can be operated from zero to high ambient pressures, tested to 350 Bar.

• Compact design – 360 gm with compact cartridge design.

• High efficiency – near zero hydraulic leakage with linear motor spool drive

• High power capability – up to 20 l/min [ 7 KW hydraulic power ].

Custom Control valve for rallying

Moto GP System

• 2 Axis Control system. Automatic clutch and Gearshift

• Uses 2 off Micro valves and miniature actuators.

•Target weight for the complete system 1.5 Kg

• Space envelope very tight between the engine casing and the fairing.


Image of moto GP bike

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6. The future of this technology.

Recent Changes: It has been widely accepted that to be relevant in the 21° Century that Motorsport has to become more relevant to ‘real-life’ technology and not just a profligate waste of fossil fuels.There are already plans for the Formula1 rules to progressively evolve through to 2020, and these changes will inevitably feed through to other other major Formulae.

Green Technology:Formula 1 in particular will be promoted as a technology showcase for greener and

more efficient technologies. F1 and ‘green’ seem contradictory, but ultimately the F1 engineers are striving to maximise the useful energy obtained from each gram of fuel....

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6. The future of this technology.

Showcase Series:Some of the newer series are designed to appeal to a younger technically knowledgeanble audience. In particular Formula E and the soon to be launched driverless ‘ Roborace series’.

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7 . Transfer of this technology to other markets.

The design of autonomous robot actuation demands light weight and high efficiencies as they are part of the ‘vehicle’ payload.Down-hole oil and gas exploration has similar constraints to motorsport namely; limited space, and high levels of temperature & vibration.

Autonomous Robotics and Oil & Gas Exploration.

Tracing the development history of automated control ...

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