Abstract
The major advantage of a motorcycle with respect to a passenger car is the possibility of the driver to tilt during cornering and thereby maintaining stability whereas a passenger car will suffer from the risk of capsizing at high speed.
This observation has lead Brink Dynamics in the Netherlands to create and develop a new concept of a man-wide vehicle that is able to tilt like a motorcycle but which offers the comfort of a passenger car, allowing further downsizing of vehicles enabling higher fuel efficiency.
This resulted into a three-wheeled passenger car referred to as the MWV, with two seats in a row consisting of two bodies, a two-wheeled rear-assembly and a front assembly being the passenger compartment including the front-fork assembly, that tilts with respect to the rear assembly. Tilting is controlled by the driver through the steering bar.
This paper includes a mathematical treatment of the behaviour of the MWV. First, the mathematical analytical equations of motions under the assumption of linear behaviour are derived with focus on steady state behaviour, and regardless of the tilting mechanism. Next, the tilting mechanism is discussed and included in the model. This allows for demonstration of the different aspects of this mechanism regarding driver feedback and rotational stiffness for varying vehicle speed under pure cornering for varying speed. The sensitivity of some further design characteristics will be discussed, showing the effects of changing parameters (e.g. mass distribution, mechanical trail, front fork hinge line inclination angle,...) on vehicle performance. In particular, the MWV will be compared with a motor-cycle and a passenger car. Finally, the dynamic performance of the vehicle will be examined based on the full dynamic equations for the MWV. Within this paper, this analysis will be restricted to stepsteer where the dynamic vehicle behaviour will be discussed with reference to its steady state performance.
In a separate subsequent EAEC paper by C. van den Brink (Realisation of High Performance Man
Wide Vehicles with an Automatic Active Tilting Mechanism), the design of the MWV will be discussed in more detail, along with the usability aspects and subjective experience with the vehicle, that are used here to validate the mathematical model.