US 5,194,795 AGranted

Drive system and a control unit therefor

AssigneeSekogiken

InventorsItsuki Bahn, Jiro Chiba

Life of this patent

Estimating the term…

Loading patent…

Abstract

A drive system capable of driving a driven member with a large force and precisely rapidly positioning the same is disclosed, with use of a control unit for efficiently driving a motor with a large torque. Upon storage of target position data from a computer in a counter circuit of a driving mode switching circuit, the driven member is driven at a high speed with a large force via a ball screw/nut mechanism by the motor which efficiently operates as a two-phase reluctance motor at a high speed with large torque. When a count of the counter circuit, decremented with movement of the driven member, reaches a first preset value, supply of a sequence of position detection signals, indicative of the motor rotational position, to an energization control circuit is changed by a signal switching circuit, so that the motor is driven in the deceleration mode until its speed reaches a preset speed, and then the motor is driven at a constant speed. When the count decreases to a second preset value, the motor is driven as a stepping motor in accordance with a signal from a stepping signal generator. The motor is stopped when the count "0" is reached, and the driven member is precisely positioned to the target position.

Claims14

Dependent claims

A control unit for controlling exciting coils of an electric motor having a rotor, comprising:

a position detector for sequentially generating a series of position detection signals upon rotation of the rotor of the electric motor;
a stepping signal generator for sequentially generating a series of stepping signals;
an energization control circuit operatively connected to the electric motor to energize and de-energize the exciting coils of the electric motor in response to the series of position detection signals and the series of stepping signals;
a counter circuit of a driving mode switching circuit operatively connected to said energization control circuit to command operation of the electric motor from a normal driving mode to a deceleration driving mode and then from the deceleration driving mode to a stepping driving mode in response to values indicative of the series of position detection signals;
a position signal switching circuit operatively connected to said counter circuit of said driving mode switching circuit and said position detector to supply the series of position detection signals to said energization control circuit when said counter circuit of said driving mode switching circuit commands a normal driving mode and to alter a sequence of the series of position detection signals to supply an altered series of position detection signals to said energization control circuit when said counter circuit of said driving mode switching circuit commands the deceleration driving mode;
and
a driving signal switching circuit of said driving mode switching circuit operatively connected to said position signal switching circuit, said counter circuit, said stepping signal generator and said energization control circuit to interrupt supply of the altered series of position detection signals to said energization control circuit and to supply the series of stepping signals to said energization control circuit when said counter circuit of said driving mode switching circuit commands the stepping driving mode.

4 more elements

A drive system, comprising:

an electric motor having exciting coils and a rotor;
a drive unit rotatably connected to said electric motor to drive a load with a driving force obtained by amplifying a force output of said electric motor;
and
a control unit for controlling said electric motor, wherein said control unit includes:
a position detector for sequentially generating a series of position detection signals upon rotation of the rotor of the electric motor;
a stepping signal generator for sequentially generating a series of stepping signals;
an energization control circuit operatively connected to the electric motor to energize and de-energize the exciting coils of the electric motor in response to the series of position detection signals and the series of stepping signals;
a counter circuit of a driving mode switching circuit operatively connected to said energization control circuit to command operation of the electric motor from a normal driving mode to a deceleration driving mode and then from the deceleration driving mode to a stepping driving mode in response to values indicative of the series of position detection signals;
a position signal switching circuit operatively connected to said counter circuit of said driving mode switching circuit and said position detector to supply the series of position detection signals to said energization control circuit when said counter circuit of said driving mode switching circuit commands a normal driving mode and to alter a sequence of the series of position detection signals to supply an altered series of position detection signals to said energization control circuit when said counter circuit of said driving mode switching circuit commands the deceleration driving mode;
and
a driving signal switching circuit of said driving mode switching circuit operatively connected to said position signal switching circuit, said counter circuit, said stepping signal generator and said energization control circuit to interrupt supply of the altered series of position detection signals to said energization control circuit and to supply the series of stepping signals to said energization control circuit when said counter circuit of said driving mode switching circuit commands the stepping driving mode.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/635,610Filed 11 Feb 1991
Priority: JP 1-13274629 May 1989
Granted: 16 Mar 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G05B 19/231
For point-to-point control: the positional error is used to control continuously the servomotor according to its magnitude
H02P 6/06
Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position;…:…
H02P 25/08
Characterised by the kind of motor: reluctance motors
G05B 2219/41047
Servomotor, servo controller till figures: recirculating ballnut, ballscrew, preloaded bearing