Wet meadows, steep slopes, and loose ground often present a challenge to agricultural vehicles. A new drive system that gets off-road vehicles safely through difficult terrain has been developed by researchers of Karlsruhe Institute of Technology (KIT) together with a partner from industry. It replaces conventional differential gears with an independent gearbox on each wheel. This way, it is possible to cope with terrain that was impassable before.
Vehicles such as tractors or slope mowers have been equipped with conventional differential gears until now. They ensure that the wheels of an axle rotate at different speeds when cornering – this operating condition is called open differential. The drawback is that if one wheel loses grip, it starts slipping and the axis’ second wheel stalls. This results in reduced traction. A locked differential, on the other hand, ensures that both wheels of an axle are linked to each other and that they rotate synchronously. Thus, the vehicle can also manage rough terrain, for example when driving on meadows, snow, or muddy ground. However, cornering is not possible.
Two Principles, One System – Advantages in Off-road Terrain
The new drive system compensates for the disadvantages of both principles: It improves wheel grip and at the same time enables exact speed compensation when cornering because it has a gearbox with individual speed control on each wheel. “The system automatically adjusts the wheel speeds to the driving situation, so that it precisely distributes the complete mechanical force from the powertrain to the wheels while controlling individual wheel speeds at the same time,” says Stefan Herr, leader of the Drive Technology research group at KIT’s Institute Mobile Machines. This way, all wheels rotate with optimum speed at maximum force transmission – the vehicle is able to move even in difficult situations.
“A tractor equipped with the Line Traction System provides more performance and better safety by getting the power to the ground – even on steep slopes or uneven ground,” says Herr. “Our test vehicle moves on where others stop. Farmland that have been unusable so far or had to be mowed by hand can now be worked by machines.” Possible uses include mowing steep slopes along motorways or meadows in mountainous regions.
Another great advantage of the system: The conventional drivetrain with a central drive unit is preserved. This makes for a compact and economic overall system without an increase in weight. Either a combustion engine or an electric motor can be used as the primary drive. “The system is also suitable for emission-free drives and thus future-proof,” explains Herr.
Research Meets Practice: From Idea to Innovation
The technology is the result of a cooperation with Müller Landmaschinen GmbH, the company that invented the system. In a series of projects, the partners developed and studied the system from the initial idea to the pre-production series. “Our research is closely linked to practice – we bring knowledge to the road or field,” says Herr. “In addition, students and doctoral researchers have been involved in the research work right from the start. This is an opportunity for them to provide input to ongoing projects and contribute to innovations early on.”
Award-winning Technology – Innovation Prize in Gold
In conjunction with the world’s largest trade fair for agriculture, the German Agricultural Society conferred the 2025 AGRITECHNICA Innovation Award in Gold to Müller Landmaschinen GmbH and their integration partner Aebi Maschinenfabrik & Co. AG. The prize is one the most prestigious awards in agricultural engineering; it underscores the successful transfer of research at KIT to industry.
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Being “The University in the Helmholtz Association”, KIT creates and imparts knowledge for the society and the environment. It is the objective to make significant contributions to the global challenges in the fields of energy, mobility, and information. For this, about 10,000 employees cooperate in a broad range of disciplines in natural sciences, engineering sciences, economics, and the humanities and social sciences. KIT prepares its 22,800 students for responsible tasks in society, industry, and science by offering research-based study programs. Innovation efforts at KIT build a bridge between important scientific findings and their application for the benefit of society, economic prosperity, and the preservation of our natural basis of life. KIT is one of the German universities of excellence.