Design and Analysis of Electric Over-actuated Vehicle Suspension

Sammanfattning: The main aim of this master thesis is to improve the performance of the Research Concept Vehicle (RCV). The RCV is an electric over-actuated vehicle developed at Integrated Transport Research Lab (ITRL) at KTH Royal Institute of Technology. The vehicle steer, camber, drive, and brake on each wheel of the vehicle. The RCV also has various operation modes such as 2WD, 4WD, 2WS and 4WS. The RCV is used as a research platform to implement, validate, and demonstrate results of various research projects.  The RCV was developed in the year 2012. There is now a requirement to improve the performance of the vehicle to create a more dynamically capable platform to do more dynamic tests with. The main aim of this thesis is to explore the possibility of upgrading the suspension system with integrated wheel hub motor, electric steering actuator and electric camber actuator. It also involves packaging of the new battery pack system and reinforcing the chassis to reduce the flex during operation.  Steps followed involves analysis of the current electric steering and electric camber actuator systems using MBD method to test the performance. With this as the base, requirements are decided as to what must be done to improve the performance by creating another MBD model to obtain the new performance figures. Also, the new battery pack is to be positioned on the base plate of the vehicle and this is achieved by placing the new battery pack onto the existing CAD model. The chassis is to be reinforced with the help of cross members, also designed on CAD software. The damper unit needs to be repositioned to accommodate the battery pack. Based on the changes in the vehicle, new hardpoints are decided for the new steering system, camber system and suspension system.  Based on the new performance figures obtained from MBD, the requirements of the new electric steering and camber actuator systems are presented. The strength in the new frame is tested using FEM method. The new position of the damper unit is tested for performance using an MBD software.  With the end of this thesis, the requirements to develop the new and improved RCV was obtained, thereby allowing for more dynamic testing to be done with the electric vehicle.