Analysis and synthesis of feedback control systems for the automatic balancing of rotating shaft systems

✍ Scribed by J. Vande Vegte

• Publisher: Elsevier Science
• Year: 1965
• Tongue: English
• Weight: 624 KB
• Volume: 2
• Category: Article
• ISSN: 0005-1098
• DOI: 10.1016/0005-1098(65)90014-2

✦ Synopsis

Automatic balancing is considered as a true feedback control problem, rather than as an automated sequence of separate operations. An adjustable correction mass must be positioned relative to a rectangular coordinate system rotating with the shaft such as to counterbalance the inherent system unbalance. This approach widens the scope of automatic balancing to include systems of which the unbalance conditions may change with time, for example, the rotor of a pump handling a fluid with some abrasive material.

Transfer functions with complex coefficients provide a natural basis for the analysis 'of this type of system, and should be useful also for the study of rotating fields in general. The root-locus technique is applied for system synthesis, using these "complex transfer functions".

The control system is multivariable because the rotating system consists of a light flexible shaft, with more than one mass with unbalance fixed along its length. Neither the system inputs (the inherent unbalances) nor the errors (the resulting unbalances) are accessible for direct measurement, and the control tends to be quite sensitive to errors in the mathematical model. Diagonalization in terms of the orthogonal modes is proposed as a basis for synthesis in order to overcome these restrictions, and to obtain relatively simple subsystems.