| 摘要 |
<p>This new unit controls the path of a workpiece chuck in motion. The chuck is part of an orbital welding system, especially for plastics. The chuck is fastened to springs and displaced by electromagnets. It describes a planar, elliptical orbit. The electromagnets are fed by a frequency converter. In the new control system, a desired value generator (1) calculates the vector of motion corresponding to the required shape of the path of motion. This is supplied both to a phase comparator (2) and to a desired and actual value comparator (3). This subtracts the measured from the desired vectors of motion to obtain the error value. This is then transformed (4) into the system of rotary co-ordinates used by the two-dimensional path controller (5). From the control error, this unit forms the complex modulation factor (m) used to zero the error. The peak amplitude of the desired vector of motion is compared (6) with that of the measured value. This is supplied to an amplitude controller (7) for the oscillation. this determines the desired amplitude of the voltage vector such that the control error at the input of the amplitude controller is zeroed. A desired voltage generator (8) calculates the actual voltage vector from the desired voltage vector and the modulation factor (m). This is supplied to the power section adjusting the output voltage of a frequency converter, so that it corresponds to the desired voltage vector. Preferably a phase controller (9) adjusts the phase of the desired value generator ( DELTA m) such that the phase error ( DELTA ) calculated (2), is averaged to zero. The frequency of the voltage tensor (Fe) is so adjusted by the frequency controller (10) that the phase ( DELTA ) error calculated (2), is averaged to zero. The operational mode can be switched over between the two controllers cited immediately above.</p> |
