Process and apparatus for positioning an object

US5942870A · kind A · utility

Assignee

• Mannesmann AG · DE

Inventors

• Rolf Koschorrek · Wetter, DE
• Stefan Elspass · Tönisvorst, DE
• Michael Hulsmann · Herdecke, DE

Key dates

• Filing date: Apr 21, 1997
• Grant date: Aug 24, 1999
• Expiry date: Apr 21, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G05B2219/43096
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A process and apparatus for positioning an object being moved along a path to a destination using a pole changing three-phase induction motor having at least two fixed driving speeds. The object is initially accelerated along the path of movement to the highest driving speed of the motor, during which the acceleration curve is determined and stored. The acceleration data is then used to calculate the location along the path in advance of the destination at which the motor is switched off and braked until reaching the next lower driving speed, whereupon the motor is operated at the next lower driving speed for a predetermined path length. The motor is then again switched off and braked until its driving speed reaches zero closely proximate the destination, at which point a motor in a gear assembly attached to the motor is operated for final low speed positioning of the object at the destination with a high degree of accuracy. The calculation of the initial switch-off location using, in the preferred embodiment, the dynamically-determined acceleration curve results in rapid and highly accurate object positioning without the need for undesirable buffer paths.