Chaos theory based control of contact force in electric railway transportation system

Improved current collection performance is one of the key requirements for railway speed-up, which is an issue of great importance in railway electric traction. At high speeds, the catenary-pantograph contact force can become zero, leading to contact loss, with well-known consequences. Some mathematical models have been developed, predicting the dynamic behaviour of this assembly and the contact force, but all of them have some degree of imprecision, (disregarding the phenomena difficult to model). They also can not be used in real time to control of contact force between the pantograph and catenary. In the present study, the contact force is divided into two components: 1) a deterministic one, corresponding to the mathematical model, 2) another one, with chaotic evolution, corresponding to the phenomena that can not be modelled. Finally, a control system is designed in order to control the pantograph dynamic regime, based on two subsystems: one for the deterministic component of the contact force, and another one for the chaotic component (using specific methods of chaotic systems). Both systems were simulated, showing promising results. Although they have been on DSP hardware implemented, they could not carry out industrial experiments.