Real Time Detection Of Vehicle Running Safety

The wheel rail contact force is the basis for study of wheel rail relationship.The traditional method of testing wheel rail forces is using instrumented wheelset. Instrumented wheelset method is the most direct and accurate method of measuring wheel-rail contact force. However there are still difficult problems to instrumented wheelset method. In order to detect the real-time wheel rail force accurately at a high speed, to find out an alternative method which is easy to operate and cost less but still with high reliability is significant.By isolating the wheelset, the wheel force balance equation is built. The indirect measurement methods of rocker type journal box positioning bogie and guide post type journal box positioning bogie are proposed in this article. By measuring acceleration, displacement and stress, the wheel rail force can be calculated. By SIMPACK simulation, error between actual and calculated values are analyzed. By roller test rig testing, error between actual and simulated values are analyzed.For the measurement of rocker type bogie wheel rail force, the difficulty lies in determining the node lateral force. By calibrating the journal box, the relationship between the stress of the test points and the node lateral force are found out. When in application, the node lateral force can be obtained by measuring the stress of the tested points.For the rocker type journal box, the lateral wheelset force can be calculated with the lateral relative displacement of the primary spring, the acceleration of the lateral wheelset and the lateral force of the axle node. The vertical wheelset force can be calculated with the lateral acceleration of the wheelset, the vertical acceleration of the wheelset, the vertical relative displacement of the primary spring and the vertical force of the primary vertical damper. Compared withtraditional measurement, this method has the advantages of easier operation and lower cost. By error analysis and safety standard evaluation, this method is safe and reliable.For the guide post type journal box. The lateral wheelset force can be calculated with the lateral relative displacement of the primary spring, the lateral acceleration of the wheelset and the the lateral relative displacement of the metal-rubber sandwich block positioner. The vertical wheelset force can be calculated with the lateral acceleration of the vertical wheelset, the acceleration of the wheelset, the vertical relative displacement of the primary spring and the vertical force of the primary vertical damper.By the simulation of SIMPACK and the test on the roller testing rig, there are errors in the indirect measurement method, but the error can be controlled within an acceptable range, this method is safe, reliable and feasible.