Electricity: motive power systems – Positional servo systems – Frequency- or phase-modulated systems
Patent
1992-05-06
1993-11-09
Shoop, Jr., William M.
Electricity: motive power systems
Positional servo systems
Frequency- or phase-modulated systems
318280, 318281, 318291, 318590, 318369, 318593, 318362, 318293, 318599, G05B 102
Patent
active
052606325
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a position control system having a direct current motor, a reduction gear and a current supply device for current pulses.
Such position control systems are known. Operation using current pulses permits extremely low mean rotational speeds of direct current motors.
DE-OS 3,330,476 discloses an arrangement for the control of a movement, especially of the object stage or of the focusing drive on a microscope. A handle with a proportional transmitter is provided, as well as a circuit which controls a motor as a function of the signals of the transmitter.
In order to combine coarse and fine drive in one system, it is provided that the circuit multiplies the transmitter signals by a factor dependent upon the transmitter speed and thus provides an overproportional dependence of the output speed upon the actuating speed. A stepping motor is provided as the motor.
Such a circuit is very costly. The dynamic range of a stepping motor, which is limited by the smallest rotary step and the greatest rotational speed with an uncomplicated pulse supply, is restricted as compared with that of a direct current motor.
From Reuter, E. "Carriage positioning in printers and plotters" DE-Z. Feinwerktechnik+Messtechnik 97 (1989), No. 10 pp. 443-446, it is known that "open loop" systems, which are in widespread use for precision positioning and which have a control loop from the motor (angle transmitter) to the input of the electronic drive system, fail to consider tolerances of following mechanical elements.
The object of the invention is to provide a position control system of the type described, which system is constructed using simple and inexpensive components, especially a simple electronic circuit, and in this case achieves a positioning movement with a large dynamic range from extremely small steps up to a high speed of displacement. Linear movement forward and backward is to be possible. Involvement in various automated functions and in controlled systems is to be possible.
In particular, the position control system is intended to be suitable for the focusing drive or the drive of the object stage of a microscope.
This object is achieved by a position control system having the features of the independent claims 1 or 5. The features of the subclaims 2 to 4 and 6 to 14 give advantageous further developments and refinements.
The invention is explained with reference to the drawing.
In the drawing:
FIG. 1 shows a general view of the arrangement of a position control system according to the invention, on a microscope
FIG. 2 in qualitative terms for low pulse frequencies
FIG. 3 corresponding to FIG. 3a).
The diagrammatic representation given in FIG. 1 shows a direct current motor 1, which, in an illustrative embodiment, is an ironless bell-type armature motor of make Faulhaber type 3557 C 012, with a reduction gear 2 and a pinion/rack combination 21 to generate a lifting movement, built onto a microscope 3 having an object stage 31, which can be adjusted in height thereby.
A current supply device 4 generates current pulses which are fed to the motor 1, and is controlled by an angular step transmitter 5, which is connected to a rotatable actuating element 51, e.g. a hand wheel or a crank. The elements 6 and 7 are described hereinbelow, and are one option. This arrangement is essentially determined by the fact that there is straightforward open-loop control, i.e. no feedback is provided. A control loop is created only via the operator by eye and hand. Of course, it is also possible to use an autofocus system to generate a control signal which directly controls the current supply device 4 and thus automates the focusing of the microscope image. The position control system itself (parts 1, 2, 21, 3, 31, 4) does not, however, include any control loop.
An essential particular feature is the utilization of the braking action of motor 1 and gear 2 by electrodynamic and frictional effects in conjunction with the formation of the current pulses by the current supply device 4.
In this connection, in FIG. 2 a) to 2
REFERENCES:
patent: 3681620 (1972-08-01), Hoge
patent: 3742333 (1973-06-01), Yurick
patent: 4504158 (1985-03-01), Ciampi et al.
patent: 4624537 (1986-11-01), Hanssen et al.
patent: 4675589 (1987-06-01), Sausner et al.
patent: 4695137 (1987-09-01), Joergens et al.
patent: 4717865 (1988-01-01), Caputo
patent: 4816726 (1989-03-01), Novis et al.
patent: 4937509 (1990-06-01), Gundlach
patent: 5129317 (1992-07-01), Gloe et al.
Leica Mikroskopie und Systeme GmbH
Masih Karen
Shoop Jr. William M.
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