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Title: Analysis on actuator dynamics in active wheelset control
Author: Weerasooriya, L.
ISNI:       0000 0004 8504 532X
Awarding Body: University of Salford
Current Institution: University of Salford
Date of Award: 2019
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This thesis presents details of an investigation conducted to evaluate the applicability and requirements of actuators in the implementation of active solid-axle wheelset control systems, for primary suspensions of the railway vehicles, and the effects of actuator dynamics on the overall active control system. The research is focused on the use of electric-mechanical (EM) actuators and it addresses on two main aspects when designing active control systems for this application. One aspect is the detailed study on actuator dynamics and parameter optimisation to improve the effectiveness/efficiency of actuator performances while the second aspect is the development of a state observer to estimate key feedback signals, for the control of actuators, which are difficult to measure using readily available sensing techniques. The study of the actuator dynamics and its optimisation is conducted by varying key factors of the electro-mechanical (EM) actuator used in this application such as gear ratio, inertial values of the motor rotor/gear-wheel and stiffness/damping at the actuator-wheelset (load) connection, while assessing key actuator performance indicators such as output torque and power consumption. This analysis provides insight in to the task of finding optimal actuator parameter values for this particular application of active wheelset control such that the effectiveness, efficiency and robustness of the overall active wheelset control system can be improved. In order to assess the developed system comprehensively, both a two-axle vehicle model and a full bogie vehicle model are being evaluated individually in the study. In addition, a state observer is developed in this study to estimate the output torque of the electro-mechanical (EM) actuator since feedback measurements are essential for the actuator control system developed in this case in order to ensure that actuator responds appropriately by delivering accurate and fast control efforts to maintain the stability of wheelsets. The formulation and design of the observer is done based only on the use of the actuator model such that it substantially reduces the complexity and difficult uncertainties related to the full model of a rail vehicle. Furthermore, a robustness assessment of the state observer is undertaken by conducting an assessment of its performance when key parameters of the model used to develop the state observer is varied within reasonable margins. The performance and robustness assessments of the state estimator integrated with the full active wheelset control system and with optimised actuator parameters are carried out with the use of both two-axle vehicle model and the full bogie vehicle model with different operational track features such as curved track and straight track with lateral irregularities with various travel speeds.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available