A Sigma-Points Kalman Filter Based Estimation for Railway Pantograph Contact Force Monitoring

The reliability of current collection is inextricably linked to the contact efficiency between the pantograph and the catenary, which significantly influences their wear state, particularly dependent on contact force. Direct measurement of pantograph–catenary contact force is typically unsuitable for continuous in-service monitoring due to the necessity for expensive and intrusive instrumented pantographs. As a result, estimation techniques for determining pantograph contact force from observed pantograph dynamics, without the usage of specific force sensors, have gained popularity in recent years. The present work proposes a model-based estimation strategy for monitoring railway pantograph contact force based on a Central Difference Kalman Filter (CDKF). Only the vertical motion of the pantograph head is needed as a measured output to enable the estimation process. The performance of the proposed estimation framework is evaluated by comparing estimated and simulated data for the coupled pantograph–catenary dynamics. The proposed model-based estimator is suitable for monitoring railway pantograph–catenary systems, as demonstrated by the results obtained in different operating conditions. Moreover, the benefits in using the CDKF are highlighted in terms of manageability of nonlinearities rather than the typically adopted Extended Kalman Filter (EKF) for model-based monitoring purposes.