Fast-track algorithms drive F1/Supercar success

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A long-standing R&D collaboration between Professor Malcolm Smith, from the University of Cambridge, and legendary British supercar maker and Formula One giant, McLaren, has led to revolutionary suspension technology now employed in all Formula One cars, and which could have wider applications, such as in the railways of the future.

  • Applied fundamental science revolutionises suspension technology now used by all Formula 1 teams and in other motor sports
  • The technology has other potential applications, such as for use on railways
  • Further research led to acclaimed suspension system in latest McLaren 720S supercar
  • Demonstrates benefits of long-term academic/industry partnerships

Professor Smith’s latest breakthrough is a semi-active suspension system for the McLaren 720S supercar, developed with PhD student Panos Brezas. In March 2018, Top Gear presenter and racing car driver, Chris Harris, described the system as “So good… It’s like witchcraft.”

The cornerstone of Professor Smith’s research is a fusion of cutting-edge mathematical theory, physics and modelling, applied to solve real-world engineering problems.  

The partnership between McLaren and Professor Smith dates back to the late 1990s, and grew out of research into mechanical networks and suspension systems forged from an earlier partnership with the Williams Formula 1 team. This collaboration led to the development of active race car suspension systems so successful that they were eventually banned by Formula One’s governing body, which demanded a return to ‘passive’ suspension set-ups.

Following the 1994 ban, Professor Smith started looking at the fundamentals of passive suspension, and entered into a collaboration with McLaren.

Standard suspension systems are based around two components – springs and shock absorbers. Together, these components absorb and dissipate energy in order to improve a vehicle’s ride and handling. Smith’s solution was ingenious – a third component, coined the Inerter, which was used to control a car’s oscillations, improve mechanical grip and cut lap times. It was developed by the McLaren team under an exclusive licensing agreement with the university, which filed a patent for it in 2001.

After extensive design studies, computer simulations, prototype development and track tests, McLaren first used the Inerter competitively in its MP4-20 car at the 2005 Spanish Grand Prix, which Kimi Raikkonen drove all the way to victory. This is hardly surprising, as the device was said to reduce lap times by up to four tenths of a second – a huge margin by Formula One standards. Raikkonen’s victory was followed by McLaren triumphs in 10 of the remaining 15 races of the season.

The Inerter remained a closely guarded secret until confidentiality restrictions associated with the original licence were lifted in 2008, and the device was then licensed to Penske Racing Shocks to provide Inerters to other Formula 1 teams. Penske has since begun supplying Inerters to other motor sports, including IndyCar, which has used them since 2012.

Paddy Lowe, Chief Technical Officer at Williams Martini Racing and former Executive Director (Technical) of the Mercedes Formula One team, is among many who acknowledge the scale of Malcolm Smith’s achievements. He says: “The Inerter… (is) now of equal rank to the spring and the damper in our constant search for higher levels of grip and stability.”

Professor Smith and his team continue to refine the technology, and have shown that inerters have great potential for railway suspension systems, where they would reduce wear on the tracks and wheels, lowering costs for the carriers and providing a more comfortable ride for the passengers. It could also be used in motorbikes to control steering oscillations and improve safety.

Professor Smith says: “New potential application areas are being thought of with some regularity – helicopters, motorcycles, machine tools… even tall buildings could benefit from the use of Inerters.

“What’s really nice is that McLaren has recognised an academic contribution – companies don’t always do that. Hopefully McLaren feel it is good to be associated with advanced academic work.”

Fast-forward to 2017, and the launch of the latest McLaren supercar – the 720S – a commercially available road model that has been hailed as the next stage of supercar evolution.

Boasting a raft of technological breakthroughs, the 212mph 720S is fractionally slower than the £800,000 McLaren P1 hypercar, is easier to drive, yet, at £200,000, is a quarter of its price. 

Crucial to the car’s extraordinary performance is a ‘semi-active’ suspension system that permits optimal control at all times, no matter the road conditions. It was designed using a theory developed by Professor Smith with his former EPSRC-supported PhD student Dr Panos Brezas. Their work was complemented by a third member of the team, McLaren’s Principal Chassis Research Engineer, Will Hoult, a former EPSRC-funded PhD student at Cambridge, who took charge of the algorithm development at McLaren.  

The team’s work helped the car’s designers to achieve superior performance in ride comfort and handling simultaneously. Sensors relay the state of the road and an on-board computer analyses the information every millisecond to find the best possible setting for components – called semi-adjustable dampers.

The results are phenomenal. BBC Top Gear presenter and racing driver, Chris Harris, who tested the car in March 2018, has described the car’s handling as “racing car like”, resulting in “a brilliant British bargain”.

Professor Smith modestly shrugs off his own contribution to the McLaren 720S supercar, saying: “I am a control systems specialist and theorist. It is just another example of a control system.”

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Professor Malcolm Smith’s research largely focuses on development of ‘control systems’ that underpin  modern technologies. He continues to redraw the boundaries motivated by the unique place occupied by the control systems field at the boundary between a mathematical science concerned with dynamics and feedback, and the interaction with physics and modelling in disparate domains.

The Inerter spy scandal: To conceal the true nature of Malcolm Smith’s revolutionary Inerter suspension component, McLaren invented a code name for it – the J-damper. This name was used internally by all employees except a small inner circle in the design team. This allowed Professor Smith to continue to publish his research on the Inerter in the open technical literature while protecting McLaren’s secret. In due course, drawings of the J-damper fell into the hands of the Renault engineering team.

McLaren subsequently brought a spying case against Renault which was upheld by the sport’s governing body – the Fédération Internationale de l’Automobile (FIA).

It is a testament to the subtle nature of the invention that although Renault were found to be in breach of the sporting code, no penalty was issued, with the reasoning that ‘Renault fundamentally misunderstood the operation of the system’ even after having access to the drawings.

Renault had assumed the device was a kind of shock absorber (a tuned mass-damper), but in fact it was a unique ‘third’ component. The Inerter completes a trio of fundamental passive mechanical elements alongside the spring and damper, forming a unified system in complete analogy with the standard electrical elements (the capacitor, inductor and resistor). The inerter allows improved control of wheel oscillations – and hence provides much greater mechanical grip, resulting in faster lap times.

After the 2007 trial, speculation as to the exact nature of the device gathered pace, with theories abounding on Internet sites and in motoring magazines. During the trial, neither McLaren nor the FIA divulged details of the J-damper.

However, in 2008, a motor sports correspondent from Autosport magazine uncovered the Cambridge connection and the fact that the so called ‘J-damper’ was in fact the Inerter. The way had opened up for the wider racing community to understand and benefit from the true nature of the Inerter and its potential to motor racing across Formula 1 and beyond.