Servo control device

• US 20030222615A1
• Filed: 05/16/2003
• Published: 12/04/2003
• Est. Priority Date: 05/28/2002
• Status: Active Grant

• Current Assignee: Toshiba Kikai Kabushiki Kaisha
• Original Assignee: Toshiba Kikai Kabushiki Kaisha
• Inventors: Ito, Takamichi, Iida, Takeshi, Aono, Ryuji, Kobayashi, Naomi
• Granted Patent: US 7,002,315 B2
• Time in Patent Office: Days
• US Class Current: 318/625
• CPC Class Codes: B29C 45/76 Measuring, controlling or regulating measuring in general G01; controlling or regulating in general G05
• CPC Class Codes: H02P 5/74 controlling two or more ac dynamo-electric motors H02P5/46, H02P5/60 take precedence

Abstract

A servo control device 10 connected to servo motors 21 to control them includes a digital logic circuit 11 having a predetermined bit width. The digital logic circuit 11 includes at least one pair of parallel arithmetical circuits 11a, 11b.

Claims

1. A servo control device connected to servo motors to control the servo motors, comprising:

a digital logic circuit having a predetermined bit width, and including at least one pair of parallel arithmetic circuits.

2. The servo control device according to claim 1, further comprising:

PWM inverters,

wherein said digital logic circuit generates PWM for controlling the PWM inverters.

3. A servo control device comprising:

a current supply unit for supplying a drive unit with a drive current for driving a target to be controlled;

a first detector for detecting at least the drive current value; and

a logical arithmetic section which introduces a current command determining the drive current for controlling the drive speed of the drive unit to move the target to be controlled to a predetermined position, and which introduces the drive current value fed back from the first detector, said logical arithmetic section outputting the current command to the current supply unit after correcting the current command by a digital logic process on the basis of the drive current value.

4. The servo control device according to claim 3, wherein the logical arithmetic unit includes:

an input register which introduces and holds the current command;

a feedback register which introduces and holds the drive current fed back from the first detector; and

a current control arithmetical unit for correcting the current command with reference to a difference between the current command from the input register and the drive current value from the feedback register.

5. The servo control device according to claim 3, wherein the drive unit is a plurality of servo motors,

wherein the current supply unit and the first detector are equal in number to the number of the servo motors,

wherein the logical arithmetic section includes:

input registers each associated with one of the servo motors to introduce and hold the drive current value fed back from the first detector;

feedback registers each associated with one of the servo motors to introduce and hold the drive current value fed back from the first detector; and

a current control arithmetic unit for correcting the current commands in time division with reference to differences between the current commands from the input registers and the drive current values from the feedback registers.

6. The servo control device according to claim 4 wherein the current supply unit is an inverter circuit controlled by a pulse width modulation signal,

wherein the logical arithmetic section further includes a pulse wave generator connected between the inverter circuit and the current control arithmetical unit, said pulse wave generator modulating a signal from the current control arithmetical unit to a pulse width modulation signal by a pulse width modulation process and outputting the modulated signal to the inverter circuit.

7. The servo control device according to claim 3, further comprising a position controller for outputting a speed command and an electrical angle based on the position of the drive unit, and a second detector for detecting the position of the drive unit,

wherein the logical arithmetic section introduces an electrical angle, which is calculated by the position controller from the position of the drive unit fed back from the second detector, and the current command, and which introduces the drive current value fed back from the first detector, said logical arithmetic section outputting the current command to the current supply unit after correcting the current command by a digital logic process with reference to the drive current value and the electrical angle.

8. The servo control device according to claim 4, wherein the input register, the feedback register and the current control arithmetical unit are incorporated in a single chip.