Model-based parameter identification of comprehensive friction behaviors for giant forging press

A new experimental apparatus was set up to investigate the actual friction characteristics on the basis of speed control of the serve system. A modified friction model was proposed due to real time varying deformation resistance. The approach to identify the parameters of comprehensive friction behaviors based on the modified model was proposed and applied to the forging press. The impacts on parameters which the external load had were also investigated. The results show that friction force decreases with velocity in the low velocity regime whereas the friction force increases with the velocity in the high velocity regime under no external load. It is also shown that the Coulomb friction force, the maximum static friction force and the vicious friction coefficient change linearly with the external load taking the velocity at which the magnitude of the steady state friction force becomes minimum as the critical velocity.