Modelling and control of a high redundancy actuator

The high redundancy actuation concept is a completely new approach to fault tolerance, and it is important to appreciate that it provides a transformation of the characteristics of actuators so that the actuation performance (capability) degrades slowly rather than suddenly failing, even though individual elements themselves fail. This paper aims to demonstrate the viability of the concept by showing that a highly redundant actuator, comprising a relatively large number of actuation elements, can be controlled in such a way that faults in individual elements are inherently accommodated, although some degradation in overall performance will inevitably be found. The paper introduces the notion of fault-tolerant systems and the highly redundant actuator concept. Then a model for a two by two configuration with electro-mechanical actuation elements is derived. Two classical control approaches are then considered based on frequency domain techniques. Finally simulation results under a number of faults show the viability of the approach for fault accommodation without re-configuratio

9 DOF railway vehicle modeling and control for the integrated tilting bolster with active lateral secondary suspension

This paper discusses the integration of tilting bolster and active lateral secondary suspension control in high speed railway vehicles with the consideration of lateral, roll and yaw dynamics of the vehicle body and two bogies. The work aims to further prove efficiencies of the active lateral secondary suspension control on improving the tilting control system performance within a full vehicle model. The symmetric strategy controlling tilt actuators with the same signal is used to implement the tilting control law. Direct implementation of the complementary filter skyhook damping control and modal control approach are used to control lateral actuators. Merits of the whole strategy are shown via simulation and appropriate comparisons