FEATURE MATERIALS IN DESIGN & PROTOTYPING Real-world data for accurate tyre modelling
With CAD and CAE technology, almost every aspect of automotive design can be verified before any metal is cut. However, one area where this is not true is in the tyre performance arena. Jaguar Land Rover is taking steps to close this gap by using technology from Kistler Instruments to generate the real-world data essential for accurate tyre modelling
T
he method adopted by Jaguar Land Rover uses Kistler’s RoaDyn wheel
force t ransducers for measuring the three forces and three moments of a rotating wheel under real-world operating conditions. A large SUV fitted with four RoaDyn measuring wheels and other sensors is used to gather data about tyre performance on a variety of on-road and off-road surfaces. An important advantage of the RoaDyn system is the data signals from the six 3-component strain gauge load cells are amplified in the load cell and fed to the wheel electronics, where the data is filtered, digitised and coded. This significantly reduces signal noise and crosstalk before the data stream is transmitted (via a rotor/stator pair, to the wheel inner side) transformed in the on-board electronics unit and output to a data acquisition device. In the JLR installation, approximately 170 data channels are acquired, with large sampling rates to capture the transient behaviour of the tyre, producing a huge amount of data for each tyre and road
relevant to real-world driving conditions. The models can then be used in computer simulations to decrease development time and increase system robustness, resulting in a more efficient development process. Simon O’Neill, technical specialist at
surface combination. JLR also run tests on a variety of on-road and off-road surfaces, ranging from vehicle dynamic platforms, to ice, snow and mud, to build up a comprehensive dataset for a highly precise, computer generated tyre model. In common with other vehicle
manufacturers, JLR currently uses data from sandpaper covered belt test rigs. Whilst these rigs offer measurement consistency and repeatability, they do not represent real-world road surfaces. The objective is to use the data from the RoaDyn system equipped vehicle to develop a more accurate tyre model,
A large SUV fitted with four RoaDyn measuring wheels is used to gather data about tyre performance
JLR, says: “In addition to providing much better quality real-time data, the Kistler RoaDyn system gives a greater insight into the performance of tyres, on and off road, which will enable JLR to reduce physical testing, especially in environments with a restricted test window, such as winter testing. This will not only cut development costs, in the medium to long-term it will allow us to co-operate with manufacturers to design the tyre we desire based on simulation results. With the robust data from the Kistler RoaDyn programme we will be able to confidently apply CAE to every part of the development process, including the tyres.”
Kistler Instruments
www.kistler.com
Model machine for prototype company
Ogle Models & Prototypes are known for manufacturing projects for the likes of Bentley, Virgin Atlantic, GSK, JLR and Lamborghini. Some of the company’s early work includes the Y- fighter and Luke Skywalker’s land cruiser from the original Star Wars film in 1976. The company wins such prestigious projects because of its skills in expert model making and handcrafting, which is mixed with modern technology such as industrial 3D printing, vacuum casting and CNC machining. To keep abreast of technology, the Letchworth
company recently purchased a Fanuc Robodrill D21LiA5. Delivered just over a year ago, the Robodrill has been an exceptional addition for the Hertfordshire business. Managing director of Ogle Models & Prototypes, Len Martin, says: “We bought the Robodrill, because we wanted to move our business on and produce much higher quality parts at a greater speed. It’s a drive that encourages everyone to be more competitive and make parts quicker.” The new machine runs faster and produces a better finish than some of our existing
22 MAY 2017 | DESIGN SOLUTIONS
machines. Even if we have a small batch of 20- off, the Fanuc is at least twice as fast as our other machines. Added to this, the quality and accuracy is also a huge factor.” Primarily, the company uses model board on
all its CNC machine tools. However, the Fanuc Robodrill has been tasked with machining everything from model board through to plastic, aluminium and steel. The BT30 Robodrill has a BBT spindle nose
interface, which provides exceptional speed, power and rigidity with its face and taper configuration. The 21-tool position machine has a maximum spindle speed of 24,000rpm and Ogle utilises this speed capability frequently. Demonstrating these high speeds and feeds,
Ogle recently manufactured a series of parts from polyurethane model board at 20,000rpm with a feed of 8m/min. Martin explains: “This is as fast as we can run the machine on detailed parts, as they have curved edges and intricate features, and this means the machine has to decelerate and accelerate. In essence, the Fanuc Robodrill gives me everything I need from a
machine. It’s extremely fast, reliable, powerful and precise. Furthermore, it has a large bed with a 4th axis capability, which means that we can machine an extremely wide variety of parts on the Fanuc at high speeds.”
Fanuc T: 024 7605 3000
www.fanuc.eu
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