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Full-Text Articles in Engineering

Output Feedback Force Control For A Parallel Turning Operation, Raghusimha Sudhakara, Robert G. Landers Jan 2003

Output Feedback Force Control For A Parallel Turning Operation, Raghusimha Sudhakara, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Parallel machine tools (i.e., machine tools capable of cutting a part with multiple tools simultaneously but independently) are being utilized more and more to increase operation productivity, decrease setups, and reduce floor space. Process control is the utilization of real-time process sensor information to automatically adjust process parameters (e.g., feed, spindle speed) to increase operation productivity and quality. To date, however, these two technologies have not been combined. This paper describes the design of an output feedback controller for a parallel turning operation that accounts for the inherent nonlinearities in the force process. An analysis of the process equilibriums explains …


Thermomechanical Behavior Of Rotor With Rubbing, Jerzy T. Sawicki, Alberto Montilla-Bravo, Zdzislaw Gosiewski Jan 2003

Thermomechanical Behavior Of Rotor With Rubbing, Jerzy T. Sawicki, Alberto Montilla-Bravo, Zdzislaw Gosiewski

Mechanical Engineering Faculty Publications

This article presents an analytical study of the dynamics and stability of rotors subjected to rubbing due to contact with seals, taking account of associated thermal effects. The seal interaction force acting on the shaft gives rise to a friction force, which is a source of heating and can induce so-called spiral vibrations. A mathematical model that has been developed couples the heat-conduction equation with the equations for motion of the rotor. Numerical simulations have been conducted that show the thermomechanical behavior of the rotor at various operating conditions. A procedure for analyzing the stability of multibearing rotors based on …