Influence of internal oscillations on force sensing in coil springs

Coil springs are a common element in compliant actuators. For closed-loop control, the force of the coil spring has to be measured. Typically, deflection sensors indirectly measure this force. Implicitly, this assumes that the coil spring is a pure stiffness, without any mass. In reality, internal oscillations can occur due to impacts or other...

Ensemble EMD-based automatic extraction of the catenary structure wavelength from the pantograph-catenary contact corce

This paper explores the use of pantograph-catenary contact force (PCCF) for monitoring of the current collection quality and detection of anomalies in the interaction between pantograph and catenary. The concept of catenary structure wavelength (CSW) is proposed as the dominant component of PCCF. It describes the signal components caused by the...