Abstract

Model based engineering is especially for the development of high performing control systems essentially. By means of suitable simplifications, they help to present technical relationships and express them mathematically. Thereby, active controllers to influence the system behavior could be developed in an efficient and reliable way. This paper deals with the design of a holistic simulation environment for an e-bike with a wheel hub motor in the rear wheel and a torque and speed sensor in the bottom bracket. A model-based approach to development using rapid control prototyping is chosen. The model design is chosen similar to the system design of the control system. The interfaces between the main models are also the interfaces of the later controller, which makes it easier to implement the system afterwards. The engine dynamics has been tested and adjusted on the model using a driving cycle. A special focus is on the interpretation of the drivers inputs by the bottom bracket sensor. At the interface between the sensor and the subordinate engine control system, any desired driving condition can be set for different types of drivers and driving situations by means of different characteristic curves. The scenarios investigated are derived from typical simulations needed during the development of e-bike drivetrains. They focus on the interaction of the hybrid system consisting of human driver and engine torque. Especially the synchronization of torques and the reaction to fast increasing stimuli were investigated. The results show a valid performance of the developed algorithm. The e-motor torque oscillates quickly and the synchronization works fine. Additionally, the algorithm to smooth the pedaling fluctuations and thereby the torque fluctuations work quite well, whereby a smooth torque is implemented. Next steps are the integration of supporting modes and the demand-orientated control.