SYMMETRY CONSIDERATIONS Motor vehicles, like most machines, have a general bilateral symmetry. Only hypotheses can be advanced to explain why this occurs. Certainly to have a symmetry plane simplifies the study of the dynamic behavior of the system, for it can be modelled, within certain limits, using uncoupled equations. However, the reason is likely to be above all an aesthetic one: symmetry is considered an essential feature in most definitions of beauty. All complex animals that evolved on our planet, including humans, have a symmetry plane defined by a vertical axis and an axis running in the longitudinal direction; symmetry. | 20 GENERAL CHARACTERISTICS SYMMETRY CONSIDERATIONS Motor vehicles like most machines have a general bilateral symmetry. Only hypotheses can be advanced to explain why this occurs. Certainly to have a symmetry plane simplifies the study of the dynamic behavior of the system for it can be modelled within certain limits using uncoupled equations. However the reason is likely to be above all an aesthetic one symmetry is considered an essential feature in most definitions of beauty. All complex animals that evolved on our planet including humans have a symmetry plane defined by a vertical axis and an axis running in the longitudinal direction symmetry is however not complete since some internal organs are positioned in an unsymmetrical way and some small deviations from symmetry are always present even in exterior appearance. When such lack of symmetry is too evident it is felt to be incompatible with the aesthetic canons developed by all human civilizations. A similar situation is encountered in all objects built by humans and as in our interest here in motor vehicles a general outer symmetry and a certain lack of symmetry in the location of the internal components. Among the most common road vehicles the only case where such a symmetry is not present is that of motorbikes with sidecar these are however perceived to be made by a main unit the motor bike that has bilateral symmetry plus a second unit the sidecar attached on a side as its name suggests. G. Genta L. Morello The Automotive Chassis Volume 2 System Design Mechanical Engineering Series Springer Science Business Media . 2009 105 106 20. GENERAL CHARACTERISTICS The sidecar often has its own symmetry plane even if such characteristics are neither needed nor useful. This consideration may confirm the idea that symmetry has in vehicles purely an aesthetic justification. A few other vehicles built for very specialized use like mobile cranes and building yard vehicles have a non-symmetrical shape when strong
