Electricity: motive power systems – Positional servo systems – With particular motor control system responsive to the...
Patent
1998-11-20
1999-12-28
Nappi, Robert E.
Electricity: motive power systems
Positional servo systems
With particular motor control system responsive to the...
2424775, G05B 1940
Patent
active
060086130
DESCRIPTION:
BRIEF SUMMARY
The invention concerns both a method for controlling a traversing device driven by means of a stepping motor according to the pre-characterizing clause of claim 1 and a traversing device according to the pre-characterizing clause of claim 11.
Such a method and such a device are known from EP 0 453 622, in which a traversing thread guide of a traversing device is driven by a stepping motor for the purpose of laying a thread. In order that the thread guide is driven back and forth within a traversing stroke, the movement of the rotor of the stepping motor is transmitted directly to the thread guide. In this case, transmission is effected by means of a belt drive.
In the traversing of a thread, it is very important that the reversal points of the traversing thread guide at the ends of the traversing stroke are always located in the same place. Furthermore, it is necessary that, at the ends of a traversing stroke, the traversing thread guide is very rapidly decelerated out of a guiding speed and re-accelerated up to a guiding speed.
In order to meet these requirements, the stepping motor is operated at a higher nominal current in the stroke reversal ranges. This enables the stepping motor to generate a higher torque. Such an increase in current, in combination with a stepping frequency necessary for generation of the high acceleration and deceleration, results in an overshooting of the rotor in the stepping motor, which is directly transmitted to the traversing thread guide. This, in addition, causes the rotor to lose its stepping sequence. An increase in current requires a correspondingly powerful stepping motor. In a larger motor, however, the increase in torque generally results in a greater moment of inertia, which is disadvantageous to the attainment of the high acceleration and braking times.
By contrast, the object of the invention is to create both a method for controlling a traversing device driven by means of a stepping motor and a device in which the traversing thread guide is guided in the reversal range with an optimal capacity utilization of the stepping motor. A further aim of the invention is to drive the traversing thread guide with as little vibration as possible in the stroke reversal range.
This object is achieved, according to the invention, by a method having the features of claim 1 and by a traversing device according to the features of claim 11.
The particular advantage of the method according to the invention is that the field quantities generated in the stepping motor are used directly for controlling the traversing device. Since the method is based on the stator flux of the stepping motor, a highly dynamic closed-loop control of the drive is achieved.
The principle of the stepping motor is based on the fact that a permanent magnet type rotor rotates within a stator with several windings. For the purpose of moving the rotor, current is applied, according to a time sequence, to the windings which are offset in relation to one another. This generates magnetic fields which, in combination with the magnetic field of the rotor, render possible the movement of the rotor. The stator is formed from a plurality of windings which, as pole pairs, determine the step width of the step,ping motor. The stepping motor torque is thus determined by the magnetic flux in the stator (stator flux) and the magnetic flux in the rotor (rotor flux). Since the rotor is in the form of a permanent magnet, the rotor flux will not vary, so that the stepping motor torque is essentially influenced by the amplitude of the stator flux and the angle in relation to the rotor flux. The method according to the invention utilizes this dependence to control the movement of the rotor and, consequently, that of the traversing thread guide. For the purpose of controlling the stator flux, a stator voltage, generated by a flux control device, is predefined. The movement of the rotor is thus controlled through varying magnetic excitations with, in each case, a predefined magnetic st-stator flux in the stator windings.
There are th
REFERENCES:
patent: 3945581 (1976-03-01), Schippers et al.
patent: 4320330 (1982-03-01), Bahr et al.
patent: 4336484 (1982-06-01), Marinko
patent: 4437619 (1984-03-01), Cary et al.
patent: 4928050 (1990-05-01), Torisawa et al.
patent: 5097189 (1992-03-01), Ito et al.
Database WPI Section EI, Week 7533, Derwent Publications Ltd., London, GB; Class V06, An 75-J3126W XP002075582 & NL 7 502 709 A (VDO Schindling AG Adolf), siehe Zusammenfassung, Jul. 31, 1978.
Patent Abstracts of Japan vol. 013, No. 106 (E-726), Mar. 14, 1989 & JP 63 277495 A (Oki Electric Ind Co Ltd), Nov. 15, 1988, siehe Zusammenfassung.
Barmag AG
Duda Rina I.
Nappi Robert E.
LandOfFree
Method for controlling a crosswinding device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for controlling a crosswinding device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for controlling a crosswinding device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2384594