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Servo system analyser pinpoints problems
Published:  16 September, 2008

Parker Hannifin has developed a software package that analyses vibration signals from servo-based drive installations and can be used to optimise the performance of these installations.

The ServoSignalAnalyser software was originally developed for use in-house by Parker, but is now being offered as a service for external customers. Previously, such analyses have the required the use of complex and expensive equipment, and have needed specialist knowledge to implement and to interpret the results. Also, the analyses have generally been limited to open control loop applications.

Parker ServoSignalAnalyser

The new software, designed to be used with Parker’s Compax 3 servo drives, can be applied to closed-loop installations and does away with the need for specialist measurement expertise. It is said to result in improved closed-loop stiffness, especially on direct-drive systems.

In one application, the software has been used to analyse the performance of a circular saw driven by a torque motor via a long, thin drive shaft. The analysis revealed that the shaft was acting like a torsion spring with resonant and anti-resonant vibration frequencies. It indicated that these could be reduced by using a shorter, reinforced drive shaft. This has been implemented and has resulted is a stiffer system, less prone to vibrations. The control loop bandwidth has been more than doubled, and the control deviation caused by an external torque disturbances has been reduced by more than 90%.