FILO – The ‘Drive-By-Wire’ Car
In the cabin of today’s cars, there are pedals, large steering wheels and dashboards. Get into any car and you are instantly restricted to a specific position: your feet must go on the pedals, your hands on the steering wheel. And yet, when one talks of ‘comfort’, it should mean that the person can change his or her position.
In Bertone’s latest concept car, the FILO, “drive by wire” technology enables a radical re-evaluation of the man-machine interface and the architecture of a car’s interior. Bertone has created a ‘living space’ devoid of the traditional constraints imposed on position and freedom of movement.
‘Mechatronics’ – the combination of mechanical devices under intelligent electronic control – is at the heart of the FILO. It is this feature which has allowed much of the interior redefinition, making possible a reassessment of how a driver interacts with the vehicle and environment in which it is being driven.
With the FILO, there is a re-invention of the man-machine interface, breaking with tradition, thinking simply and focusing attention on the personal. Steering, accelerator, brakes, gear shifter and clutch are all controlled “by wire”; the same technology used in the controls of a modern aircraft. The abolition of mechanical links for all these functions in favour of electronic signals sent along the wires has created new spaces that allow for the complete re-design of the interior, fully exploiting the broad freedoms that the power of electronics bring.
Finally freed of the bulky and potentially dangerous presence of the steering column, the designers have been able to consider a dashboard free of obstructions and constraints, a large free surface, simple, clean, relaxing. A central binnacle houses the information and driving equipment, while the air outlets disappear and the air conditioning is diffused evenly. The waved floor offers various possibilities for the driver to rest his feet, no longer restricted by the presence of pedals. Both front and rear seats have the appearance of lounge sofas, with the rear positioned higher than that of the front to give greater forward visibility for the passengers. Entrance into the car is made easier due to the absence of the central pillar (which could present a structural issue when safety is considered).
The technology
SKF, the automotive industry’s leading supplier of bearing and sealing solutions, worked with Bertone on the drive-by-wire technologies and drew on its deep pool of skills for the FILO concept. Its Drive-By-Wire business unit, based in Italy, has driven the project from the beginning, taking design responsibility for the systems. Support has come from other areas of SKF, such as SARMA, SKF’s avionics and aerospace arm which provided the development basis for the FILO concept’s man-machine interface.
The braking system was developed jointly with Brembo, SKF’s partner in brake-by-wire. Brembo’s knowledge and experience in caliper design and braking systems, coupled with compact, smart electro-mechanical actuating units from SKF has produced a braking system that, even at this interim stage in the solution development, rivals conventional hydraulic arrangements in performance.
Smart electro-mechanical actuating units are at the heart of drive-by-wire. Ball and roller screws convert between rotary and linear motion. Compact electric motors and gearing systems provide the power. Smart control, a combination of sensors, logic and control units, brings by-wire to reality. Control systems for the steering, clutch and shift and braking are all SKF developments as well.
The benefits of full by-wire operation, integrating throttle, braking and steering as hand controls are found in the FILO. The centre boss accommodates all other controls that the driver needs. Gear selection is made by the button system already used in F1 and WRC cars. Lights, wipers, audio, heating and air-conditioning are all located within driver’s immediate reach.
By-wire is also an environment-friendly technology, dispensing with hydraulic oil for the braking and power steering systems. The “feel” for the driver’s controls frorn the mechatronic actuation systems is provided by a closed-loop sensor and feedback system. Thus “by wire” actuation is actually very much more than a simple replcement of a hydraulic or mechanical system with an electric motor and gearing arrangement.
The electro-mechanical actuating units are “smart”. Taking the brake electro-mechanical actuating unit as an example, during operation, the actuators must provide information on the forces exerted, overall travel and so on. All the control systems, whether for the clutch, gearshift or steering, are coupled with the related vehicle stability and safety systems or engine functions. At the heart of the smart actuating unit is an electro-mechanical arrangement that converts rotary motion to linear travel.
SKF’s long experience in producing ball and roller screws for the industrial markets and positioning systems for the machine tool industry provided a secure foundation on which to develop solutions suitable for the automotive industry.
The modern car is not truly maintenance-free. The smart electro-mechanical actuator units must therefore offer in-service life and servicing requirements at least as good as the traditional mechanisms they are to replace. Sealing such systems is essential. Dirt, water – even brake-pad dust – can have a devastating effect on the life of such high-precision assemblies.
Chicago Rawhide, the sealing arm of the SKF Group, is a recognised leader in sealing systems for general industrial applications and, specifically, automotive engines and transmissions. The skills they bring to design and elastomeric material selection are crucial in keeping the adverse elements from the environment at bay.
Safety is always critical. As with all things “new”, there is apprehension, but the overall system design of the mechatronic controls has been evaluated using the same techniques applied to the fly-by-wire systems employed in many of today’s airliners like the Airbus and also fighter jets.
The FILO is thus a vision of the future automobile and Bertone believes it’s not that distant either, perhaps within a couple of model generations from now.
