Modelling and Enhanced Stability of a Steer by Wire Bicycle

In this Master Thesis an innovative approach to bicycle design by introducing a steer-by-wire system is studied, where the traditional mechanical link between the handlebar and fork is replaced by servomotors, sensors, and a controller. The main goals of this research are the following: to begin with, a detailed model of the bicycle and the steer-by-wire system was set up in Simpack, a multibody system simulation software. In this phase, stability analyses are performed, and the need for a control strategy to resolve instabilities at lower forward speeds is highlighted. A linear, discrete time controller was developed in MATLAB-Simulink, and a co-simulation environment was set up between the two softwares to test the controller in conjunction with the bicycle model. Based thereon, different setups of the control parameters were analysed to evaluate the potential of steer-by-wire systems as stability-enhancing mechanisms for straight ahead motion under the constraint of the maximum torque output of the system’s actuators. Finally, the interaction of the controller with steering inputs from the virtual driver during cornering and other common cycle manoeuvres was analysed. This research aims to advance our understanding of bicycle control mechanisms and contribute to the development of safer cycling technologies.