The evolution of electronics in the vehicle industry has introduced the possibility for more X-by-wire systems in future vehicles. However, the use of steer-by-wire systems has not yet been widelyimplemented. This opens up an opportunity to explore strategies around the potential use of such asystem.The purpose of the project was to evaluate how to design a variable steering ratio which would give asuitable ratio in all speeds. This would, in turn, make it possible to reduce the need for large steeringwheel angles. Additionally, steering wheel designs which can be implemented with a steer-by-wiresystems are discussed and what possibilities there are to move certain interfaces to the steering wheel.The evaluation process consisted of driving a real car with a constant steering ratio in normal trafficand later modelling a variable steering ratio and testing it in a simulator. This was to get data on howlarge steering wheel angles that are needed in different driving scenarios to then be able to design asuitable variable steering ratio. The tests conducted on normal roads in a real car has shown that thedriver utilises the whole steering range (full lock-lock distance) at speeds below 30 km/h and about±10° on the steering wheel at high speeds. The tests conducted in the simulator show that the variablesteering ratio presented in this report decreases the workload on the driver most of all at speeds below30 km/h.The variable steering ratio presented has been compared with a fixed steering ratio in the simulatorand the tests show that the variable steering ratio works similar to the fixed steering ratio in the samescenarios. The variable steering ratio also decreases the need for a steering wheel angle greater than±180°.

Driven by the need for automation and autonomy as well as the need to reduce resources and emissions, the automotive industry is currently undergoing a major transformation. Technologically, this transformation is addressing a wide range of challenges and opportunities. The optimal control of all components is significant for the sustainable development and eco-friendly operation of vehicles. Additionally, robust control of the actuators forms the basis for the development of driver assistance systems and functions for autonomous driving. The actuators of the steering system are particularly important, as they enable safe and comfortable lateral vehicle control. Therefore, the model-based development and virtual simulation of an innovative highly robust control approach for modern Steer-by-Wire systems were conducted in this thesis. The approaches and algorithms described in this thesis allow the design of robust Steer-by-Wire systems and offer the opportunity to conduct many investigations in a computer-aided virtual environment at an early stage in the development process. This reduces time- and cost-intensive testing on prototypes, avoids unnecessary iterations in the design and significantly increases the efficiency and quality of the development. The desired high degree of robustness of the steering control also ensures that the parameterization of the steering feel generator can be freely selected for the individual application. This enables safe and comfortable vehicle lateral control.In summary, the research results described in this thesis accelerate the development of new, modern Steer-by-Wire systems whose robust design forms the basis for the realization of functions for highly automated and autonomous driving.