As cars and mobility advance, the performance requirements of their tyres must keep pace. In support of the evolution towards connectivity, automation, ride sharing and electrification (CASE), a tyre’s safety, efficiency and environmental credentials are critical. Tyre makers, such as Falken and its parent company Sumitomo Rubber Industries (SRI), are turning to more advanced manufacturing technologies to develop increasingly intelligent tyre products.
As car manufacturers invest billions of dollars into developing CASE technologies – which are set to revolutionise the mobility space within the next decade – Tier 1 suppliers are working on a plethora of technologies to support.
One area of significant importance that could reap dividends is tyres. The key interface between the car and the road, tyres are becoming smarter. Research and development is accelerating to create products that not only deliver the performance and safety required today, but also act as a key enabler for the advancing future mobility ecosystem. New processes, materials and technologies, including artificial intelligence (AI), are enabling engineers to make step changes in this field.
Analysing tyre material properties
Tyres are produced from a range of materials like rubber, reinforcing filling substances (eg silica and carbon black), along with various chemicals and additives – providing opportunities to enhance the compounds and construction. A tyre’s properties are derived from the complex interaction between these materials.
“With a combination of both natural and synthetic materials, tyres generally degrade over time and during wear, which causes them to lose some of their performance attributes,” explains Sumitomo Rubber’s Dr Bernd Löwenhaupt.
“Even sitting on a shelf in the right conditions for two years, a tyre can lose up to 10% of its wet grip performance.”
Seeing and understanding the complex effects on a tyre’s materials and structure in order to reduce such degradation was extremely difficult, until now.
SRI has partnered with Professor Kimi Haseyama from Hokkaido University in Sapporo, Japan, to develop its first technology that utilises AI for deep learning in the development of tyres. Named ‘Tyre Leap AI Analysis’ for its ability to ‘leap’ forward in time, it predicts present and future conditions based on past trends.
It anticipates how the properties and structure of the rubber will change throughout a tyre’s lifecycle due to load, wear and age, and allows engineers to get an insight into how performance will be affected.
Using AI technology to analyse tyre properties
As the fifth largest tyre maker in the world, SRI’s knowledge of rubber science, garnered over 110 years, has been critical to the accuracy of the technology’s predictions. SRI provided real-world data along with huge quantities of advanced tyre images to ‘feed’ the AI technology.
A vast number of images showing the complex internal structures of both new and old tyres were collated. These images were captured using an electron microscope, which utilises a beam of accelerated electrons as a source of illumination rather than visible light.
The advantage being that electron microscopes have a higher resolution and magnification of up to two million times. In comparison, a light microscope offers magnification of between 1,000-2,000 times.
The data and detailed images were fed into an algorithm developed by Professor Haseyama and his team at Hokkaido University, which set about analysing the data and images in order to extrapolate estimated rubber properties.
The applications of AI technology on tyre design
The AI technology detects and assesses the rubber properties of an old tyre, as well as the surface and internal structure, and compares it to that of a new tyre. From this information it develops patterns across a tyre’s lifecycle and provides this statistical feedback.
As a result, Tyre Leap AI Analysis can accurately predict how materials and structures will change over time, and with it, how these physical properties will manifest as performance traits, such as how the rubber will deform when subjected to external forces.
Engineers are utilising this advanced materials knowledge to develop new tyre compounds and forecast its properties during its lifecycle to create tyres that will not only last longer but also deliver more consistent performance.
“The AI technology far exceeds human capabilities to predict changes,” explains Löwenhaupt. “It has uncovered patterns of ageing and wear within the compound and structure that will significantly contribute to future tyre technologies and advanced products.”
And as the AI technology is fed more data, it continues to learn and develop. The number of properties that this technology can estimate will continue to increase over time.
Tyre Leap AI Analysis sits within a collection of advancements that SRI calls ‘Performance Sustaining Technology’. Löwenhaupt expands on this: “Performance Sustaining Technology, or PST, enables tyres to maintain like-new performance for longer. It suppresses the degradation of performance that occurs during wear and its deterioration over time. This has huge potential for the tyre industry, and also for consumers as vehicles become smarter.
“One such benefit will be its contribution to the safety of autonomous vehicles. Because the tyre’s performance does not change as much over time, there are far fewer variables that an autonomous vehicle must take into account. The technology will enable us to develop tyres that will perform better, be safer for longer and will need to be serviced less frequently. This also has an environmental benefit as they won’t need to be replaced as often.” As greater emphasis is placed on reducing landfill and the wider carbon circle this is increasingly important for manufacturers.
The real-world impact of intelligent tyres
So, what does this actually mean for real world use on the road? In part, more supple tyres. “Rubber hardens as softening agents seep out over time, which reduces grip,” explains Löwenhaupt. “By ensuring the rubber stays pliable we can sustain traction performance. Additionally, improving wear resistance means the groove depth in the tread can be maintained for longer lasting hydroplaning performance.
“Ultimately, our aim is to develop tyres that maintain the same performance, with zero change, until they are replaced. This of course means further improving resistance to wear and deterioration over time. However, as it is not possible to completely prevent performance degradation due to these and other causes, we are also working to establish technologies that allow tyres to self-repair or even to compensate for degradation by actually improving their performance over time.”
Following the introduction of Tyre Leap AI Analysis in 2019, the technology has already resulted in a new tyre product – Enasave Next III. Launched in December 2019 in Japan, the tyre is rated A-A, the highest possible for energy efficiency, as well as wet braking.
4D Nano Design Technology analysing tyre material properties
Tyre Leap AI Analysis is not the only advanced technology that has been utilised to develop the performance of this tyre. It has been used in tandem with SRI’s Advanced 4D Nano Design Technology, which uses quantum chemistry calculations. Through research into the molecular structure of tyre materials using particle accelerators and advanced simulation computers, SRI has succeeded in simulating and controlling the molecular structure of rubber compounds used for tyres at the nano level.
For example, it has analysed how and where superfluous heat is generated in the tyre, which typically results in loss of energy and increases rolling resistance, which in turn affects fuel consumption. The Advanced 4D Nano Design Technology has helped minimise this at the molecular level to deliver fuel savings of up to 5% compared to conventional tyre models.
What’s in store for intelligent tyres?
Tyre Leap AI Analysis and Advanced 4D Nano Design Technology are two core materials technologies that are contributing to what SRI is deeming its ‘Smart Tyre Concept’. This brings together a suite of advancements and Performance Sustaining Technologies that will support the mobility requirements of electrification, automation and ride sharing.
These include: airless tyres, that will banish not only flat tyres but also the laborious processes of tyre inflation and pressure monitoring; sensing core technology that detects tyre pressure from existing wheel speed signals to eliminate additional sensors and reduce cost and maintenance; and active tread, which changes the functionality of the rubber in line with the current road surface. Since 2015, SRI has been announcing elements of these technologies, with the aim of all being active and implemented on tyres by 2030.
And it’s not just the tyres themselves that will be critical to the advancing mobility technology. Autonomous vehicles at Level 4 and above will need to be carefully maintained, with technical support teams notified should a vehicle be showing any signs of excessive wear or damage. Remote tyre pressure monitoring systems (TPMS) can support this. A direct TPMS mounted inside the tyre rim can transmit pressure data to an onboard computer system, which forwards the information to a control centre. It allows the pressure of each individual tyre to be monitored and for maintenance to be actioned in the event of any pressure changes.
SRI has already successfully established links between its own TPMS and an Autonomous Driving Control Centre at GRANTS, the Centre for Research on Adoption of NextGen Transportation Systems, based at Gunma University in Japan.
At present, tyres are still considered a distress purchase; something to change when they wear out or fail. But in the future, it’s clear they will play a greater role in the performance, safety and efficiency of our cars.