Degree of freedom digital control system for a hydraulic press

• US 5,068,779 A
• Filed: 03/28/1989
• Issued: 11/26/1991
• Est. Priority Date: 03/28/1989
• Status: Expired due to Fees

• Current Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Original Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Inventors: Sullivan, Michael T., Tock, Gary S.
• Primary Examiner(s): RUGGIERO, JOSEPH F
• Application Number:
  US07/329,572
• Time in Patent Office: 973 Days
• Field of Search: 364/167.01, 364/473, 364/476, 264/40.1, 264/40.3, 264/40.5, 264/40.7, 425/135, 425/145, 425/150, 425/162, 425/163, 425/167, 100/53, 100/99
• US Class Current: 700/56
• CPC Class Codes: B30B 15/26 Programme control arrangements
• CPC Class Codes: G05B 19/4147 characterised by using a programmable interface controller [PIC]
• CPC Class Codes: G05B 2219/43162 Motion control, movement speed combined with position
• CPC Class Codes: G05B 2219/45137 Punch, stamp, also with use die, mould

Abstract

A digital computer-based degree of freedom (DOF) control system for driving a moving ram of a hydraulic press about a plurality of degrees of freedom as a function of a preestablished motion control program. Actuators responsive to actuator commands drive the moving ram at a plurality of spaced locations. Digital feedback data representative of the positions and loads of the moving ram at the spaced locations are stored in memory. Motion control data representative of the motion control program is also stored in memory. A digital control computer implementing servoloop operations generates the actuator commands as a function of the feedback data and motion control data.

Claims

1. A digital computer based degree of freedom (DOF) control system for driving a movable member about a plurality of degrees of freedom as a function of a preestablished motion control program, including:

actuators responsive to actuator commands for driving the movable member at a plurality of spaced driving locations;

feedback means for providing;

digital position feedback data representative of positions of the movable member at the spaced driving locations; and

digital load feedback data representative of loads on the moving member at the spaced driving locations;

memory means for storing data including the position feedback data, load feedback data, and data representative of the preestablished motion control program; and

digital control computer means coupled to the actuators, feedback means, and memory means for generating the actuator commands as a function of the position feedback data, the load feedback data and the preestablished motion control program, the digital control computer means including;

DOF feedback sum means for computing position DOF feeback sums, load DOF feedback sums and centroid DOF feedback sums as a function of the position feedback data and load feedback data;

command generator means for computing servoloop input commands including, position servoloop commands, load servoloop input commands and centroid servoloop input commands as functions of the preestablished motion control program;

DOF servoloop means for computing servoloop output commands including, position servoloop output command, load servoloop output commands and centroid servoloop output commands as functions of associated DOF feedback sums and servoloop commands;

mode select means for selecting servoloop output commands from among the position servoloop output commands, the load servoloop output commands and the centroid servoloop output commands as a function of the motion control program; and

DOF output sum means for computing the actuator commands as a function of the selected servoloop output commands.

2. The control system of claim 1 wherein:

the feedback means includes digital feedback computer means for providing;

periodically generated sets of position feedback data dn load feedback data; and

generation of the sets of position feedback data and load feedback data; and

the digital control computer means generates the actuator commands as a function of the handshake signals.

3. The control system of claim 2 wherein the DOF feedback sum means of the digital control computer means computes position DOF feedback sums, load DOF feedback sums and centroid DOF feedback sums in response to the handshake signals.

4. The control system of claim 1 wherein:

the memory means includes current value memory for storing;

the digital position feedback data and load feedback data provided by the feedback means;

the position, load and centroid DOF feedback sums computed by the DOF feedback sum means;

the position, load and centroid servoloop input commands computed by the command generator means;

the position load and centroid servoloop output commands computed by the DOF servoloop means;

the DOF feedback sum means includes means for accessing the current value memory to obtain position and load feedback data, and means for storing the computed DOF feedback sums in the current value memory;

the DOF servoloop means includes means for accessing the current value memory to obtain the servoloop commands and DOF feedback sums, and means for storing the computed servoloop output commands in the current value memory; and

the DOF output sum means includes means for accessing the current value memory to obtain the DOF servoloop output commands, and means for storing the computed actuator commands in the current value memory.

5. The control system of claim 4 wherein:

the actuators are responsive to analog actuator commands; and

the digital control computer means further includes digital-to-analog converter means for accessing the current value memory to obtain the digital actuator commands and for generating analog output commands as a function of the accessed commands.

6. The control system of claim 1 wherein:

the memory means includes means for storing DOF feeback sum limit data; and

the digital control computer means further includes DOF feedback sum limit checking means for comparing the computed DOF feedback sums to the stored DOF feedback sum limit data.

7. The control system of claim 1 wherein:

the actuators include;

moving ram actuators responsive to moving ram actuator commands; and

power module actuators responsive to power module actuator commands; and

the digital control computer means includes;

moving ram control computer means for generating the movign ram actuator commands;

power module control computer means for generating the power module actuator commands; and

press control computer means coupled to the memory means for controlling the moving ram control computer means and power module control computer means as a function of the motion control program.

8. The control system of claim 7 wherein the moving ram control computer means includes:

moving ram DOF feedback sum means for computing position DOF feedback sums and load DOF feedback sums as a function of the position feedback data and load feedback data;

moving ram command generator means for computing position servoloop input commands and load servoloop input commands as a function of the motion control program;

moving ram DOF servoloop means for computing position servoloop output commands and load servoloop output commands as a function of associated DOF feedback sums and servoloop input commands;

moving ram mode select means for selecting position servoloop output commands and load servoloop output commands as a function of the motion control program; and

moving ram DOF output sum means for computing the moving ram actuator commands as a function of the selected position and load servoloop output commands.

9. The control system of claim 8 wherein:

the moving ram DOF servoloop means includes;

vertical load servoloop operation means;

vertical position servoloop operation means;

roll position servoloop operation means; and

roll load servoloop operation means; and

the moving ram mode select means includes;

vertical mode select means for selecting output commands from either the vertical load servoloop operation means or the vertical position servoloop operation means, and means for coupling the selected servoloop output commands to the moving ram DOF output sum means; and

roll mode select means for selecting servoloop output commands from either the roll position servoloop operation means or the roll load servoloop operation means, and means for coupling the selected servoloop output commands to the moving ram DOF output sum means.

10. The control system of claim 7 wherein the power module control computer means includse:

power module DOF feedback sum means for computing position DOF feedback sums, load DOF feedback sums and centroid DOF feedback sums as a function of the position feedback data and load feedback data;

power module command generator means for computing position servoloop input commands, load servoloop input commands and centroid servoloop input commands as a function of the motion control program;

power module DOF servoloop means for computing position servoloop output commands, load servoloop output commands and centroid servoloop output commands as a function of the associated DOF feedback sums and servoloop unit commands;

power module select means for selecting position servoloop output commands, load servoloop output commands and centroid servoloop output commands as a function of the motion control program; and

power module DOF output sum means for computing the power module actuator commands as a function of the selected position, load and centroid servoloop output commands.

11. The control system of claim 10 wherein:

the power module DOF servoloop means includes;

vertical position servoloop operation means;

vertical load servoloop operation means;

roll position servoloop operation means;

roll centroid servoloop operation means;

pitch position servoloop operation means;

pitch centroid servoloop operation means; and

warp position servoloop operation means;

the power module mode select means includes;

vertical mode select means for selecting servoloop output commands from either the vertical position operation means or the vertical load servoloop operation means, and means for coupling the selected servoloop output commands to the power module DOF output sum means;

roll mode select means for selecting servoloop output commands from either the roll position servoloop operation means or the roll centroid servoloop operation means, and means for coupling the selected servoloop output commands to the power module DOF output sum means; and

pitch mode select means for selecting servoloop output commands from the pitch position servoloop operation means or the pitch centroid servoloop operation means, and means for coupling the selected servoloop output commands to the power module DOF output sum means.

12. The control system of claim 1 wherein:

the memory means includes means for storing servoloop gain compensation parameter data; and

the DOF servoloop means includes means for computing the servoloop output commands as a function of the gain compensation parameter data.

13. A degree of freedom (DOF) control system for control of the movement of a body in a plurality of degrees of freedom, the control system comprising:

motion actuators responsive to actuator commands for applying force to the body at a plurality of mutually spaced locations;

feedback means for providing feedback information relating to changes in position of selected points on the body; and

signal processing means for generating the actuation commands, the signal processing means including;

memory for storage of contemporaneous servoloop output commands, feedback information and DOF feedback sums;

feedback summing means responsive to the feedback information accessed from memory for generating DOF feedback sums and storing DOF feedback sums to memory;

command means operating on a motion control procedure for generating servoloop input commands;

DOF servoloop means for generating the servoloop output commands as a selectable function of the DOF feedback sums and the servoloop input commands; and

DOF summing means responsive to the servoloop output commands for generating actuator commands.

14. The control system of claim 13 wherein:

the feedback means includes;

position feedback sensors for providing position information relating to selected points on the body; and

load feedback for providing load information occurring at selected points on the body;

the feedback summing means being further responsive to the position feedback data and load feedback data accessed from memory for generating the DOF feedback sums including, position feedback sums, load feedback sums and centroid feedback sums.

15. The control system of claim 14 wherein:

the servoloop input command signals generated by the command means include position servoloop input command signals, load servoloop input commands and centroid servoloop input commands; and

,

the servoloop output commands generated by the DOf servoloop means include, position servoloop output commands, load servoloop output commands and centroid servoloop output commands, each being generated as a function of associated DOF feedback sums and servoloop input commands.

16. The control system of claim 15 and further comprising:

mode select means for selecting from among the servoloop output commands as determined by the motion control program; and

DOF output sum means for generating the actuator commands as a function of the selected servoloop output commands.

17. The control system of claim 16 wherein the feedback means further comprises means for providing associated substantially contemporaenous sets of position and load feedback information and means for providing handshake signals associated with generation of the mutually contemporaneous sets of position and feedback information.

18. The control system of claim 17 wherein the DOF feedback sum means generates position DOF feedback sums, load DOF feedback sums and centroid DOF feedback sums in response to the handshake signals.

19. The control system of claim 18 wherein:

the memory includes contemporaneous value memory for storing;

the position feedback information and load feedback information provided by the feedback means;

the position, load and centroid DOF feedback sums computed by the DOF feedback sum means;

the position, load and centroid servoloop input commands computed by the command generator means; and

the position, load and centroid servoloop output commands computed by he DOF servoloop means;

he DOF feedback sum means includes means for accessing the current value memory to obtain position and load feedback data, and means for storing the computed DOF feedback sums in the current value memory;

the DOF servoloop means includes means for accessing the current value memory to obtain the servoloop commands and DOF feedback sums, and means for storing the computed servoloop output commands in the current value memory; and

the DOF output sum means includes means for accessing the current value memory to obtain the DOF servoloop output commands, and means for storing the computed actuator commands in the current value memory.

20. The control system of claim 16 wherein:

the memory includes means for storing DOF feedback sum limit information; and

the signal processing means further includes DOF feedback sum limit checking means for comparing the DOF feedback sums to the stored DOF feedback sum limit information.

21. The control system of claim 16 wherein:

the motion actuators include;

moving ram actuators rseponsive to moving ram actuator commands; and

power module actuators responsive to power module actuator commands; and

the signal processing means further includes;

moving ram control means for generating the moving ram actuator commands;

power module control means for generating the power module actuator commands; and

press control means coupled to the memory for controlling the moving ram control means and power module control means as a function of the motion control information.

22. The control system of claim 21 wherein the moving ram control means includes:

moving ram DOf feedback sum means for computing position DOF feedback sums and load DOF feedback sums as a function of the position feedback information and load feedback information;

moving ram command means for generating position servoloop input commands and load servoloop input commands as a function of the motion control procedure;

moving ram DOF servoloop means for generating position servoloop output commands and load sevoloop output commands as a function of associated DOF feedback sums and servoloop input commands;

moving ram mode select means for selecting servoloop output commands from the position servoloop output commands and load servoloop output commands as a function of the motion control procedure; and

moving ram DOF output sum means for computign the moving ram actuator commands as a function of the selected servoloop output commands.

23. The control system of claim 21 wherein the power module control means includes:

power module DOF feedback sum means for generating position DOF feedback sums, load DOF feedback sums and centroid DOF feedback sums as a function of the position feedback, information and load feeback information;

power module command means for generating position servoloop input commands, load servoloop input commands and centroid servoloop input commands as a function of the motion control procedure;

power module DOF servoloop means for generating position servoloop output commands, load servoloop output commands and centroid servoloop output commands as a function of the associated DOF feedback sums and servoloop input commands;

power module mode select means for selecting servoloop output commands from the position servoloop output commands, load servoloop output commands and centroid servoloop output commands as a function of the motion control procedure; and

power module DOF output sum means for computign the power module actuator commands as a function of the selected position, load and centroid servoloop output commands.

24. The control system of claim 22 wherein:

the moving ram DOF servoloop means includes;

a vertical load servoloop operator;

a vertical position servoloop operation;

roll position servoloop operator; and

roll load servoloop operator;

the moving ram mode select means includes;

vertical mode select means for selecting output commands from either the vertical load servoloop operator or the vertical position servoloop operator, and means for coupling the selected servoloop output commands to the moving ram DOF output sum means; and

roll mode select means for selecting servoloop output commands from either the roll position servoloop operator or the roll load servoloop operator, and means for coupling the selected servoloop output commands to the moving ram DOF output sum means.

25. The control system of claim 23 wherein:

the power module DOF servoloop means includes;

a vertical position servoloop operator;

a vertical load servoloop operator;

a roll position servoloop operator;

a roll centroid servoloop operator;

a pitch position servoloop operator;

a pitch centroid servoloop operator; and

a warp position servoloop operator;

the power module mode select means includes;

vertical mode select means for selecting servoloop output commands from either the vertical position operator or the vertical load servoloop operator, and means for coupling the selected servoloop output command to the power module DOF output sum means;

roll mode select means for selectign servoloop output command from either the roll position servoloop operator or the roll centroid servoloop operator, and means for coupling the selected servoloop output commands to the power module DOF output sum means; and

pitch mode select means for selecting servoloop output commands from the pitch position servoloop operator or the pitch centroid servoloop operator, and means for coupling the selected servoloop output commands to the power module DOf output sum means.

26. The control system of claim 13 wherein:

the memory includes means for storing servoloop gain compensation parameter information; and

the DOF servoloop means includes means for changing the servoloop gain compensation parameter information as a function of the servoloop input command.

27. The control system of claim 13 wherein:

the memory includes means for storing servoloop gain compensation parameter information; and

the DOF servoloop means includes means for changing the servoloop gain compensation parameter information as a function of the DOF feedback sums.