The wheel corner module represents a new technology for controlling the motion of a vehicle. It is based on a modular design around the geometric boundaries of a conventional wheel. The typical WCM consists of a wheel containing an electrical in-wheel propulsion motor, a friction brake, a steering system and a suspension system. Generally, the braking,steering and suspension systems are controlled by means of electrical actuators.
The WCM is designed to easily, by means of bolted connections and a power connector, attach to a vehicle platform constructed for the specific purpose. All functions are controlled via an electrical system, connecting the steering column to the module. A WCM vehicle can contain two or four wheel corner modules.The purpose of this thesis is to serve as an introduction to wheel corner module technology.The technology itself, as well as advantages and disadvantages related to wheel corner modules are discussed.
An analysis of a variety of wheel corner module concepts is carried out. In addition, simulations are conducted in order to estimate how an increased unsprung mass aects the ride comfort and handling performance of a vehicle.Longitudinal translation over two types of road disturbance proles, a curb and a bump,is simulated. A quarter car model as well as a full car model is utilized. The obtained results indicate that handling performance is deteriorated in connection to an increase dunsprung mass. The RMS value of the tire force fluctuation increases with up to 18%,when 20 kg is added to each of the rear wheels of the full car model. Ride comfort is deteriorated or enhanced in connection to an increased unsprung mass, depending on the disturbance frequency of the road.
When subjected to a road disturbance frequency below the eigen frequency of the unsprung mass, ride comfort deterioration is indicated. The RMS vertical acceleration of the sprung mass increases with up to 6%, in terms of the full car model. When subjected to a road disturbance frequency above the eigen frequency of the unsprung mass, decreased RMS vertical acceleration of up to 25% is noted, indicating a significantly enhanced ride comfort. Implementation of wheel corner module technology enables improved handling performance,safety and ride comfort compared to conventional vehicle technology. Further development, e.g. in terms of in-wheel motors and alternative power sources, is however required. In addition, major investments related to manufacturing equipment and technology is regarded as a significant obstacle in terms of serial production.
Author: Hag, Johan