A practical approach to active lateral suspension for railway vehicles

Background: Active lateral suspension (ALS) technologies have been well developed for several decades, but they have not been widely used in service operation due to relatively high costs for implementation and maintenance and concerns about fail-safe. Therefore, this paper suggests a more practical approach for the active suspension system, designed to achieve target performance with easy implementation and maintenance and high fail-safe. Methods: The control performance target and actuator type are determined from the vibration energy that the ALS has to absorb along the weight function for ride quality evaluation. The installation position of actuator and sensor is decided to decrease the time that it takes for field engineers to check the actuator for maintenance. In addition to fail-safe function of ALS system, conventional hydraulic lateral damper is installed in parallel with ALS to reduce the concern about fail-safe of the ALS. Results: Through the roller rig and filed tests, the performance of the proposed ALS was validated. Lateral ride quality was improved 7.1dB and 6.7dB in the roller rig test and field test, respectively. The fail-safe strategy was also verified during the filed test. Conclusion: Test results show that the suggested ALS is designed appropriately and can be used in practical implementation.