Synchronous control device

• US 20050241843A1
• Filed: 04/21/2005
• Published: 11/03/2005
• Est. Priority Date: 04/28/2004
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Hishikawa, Tetsuo, Fujibayashi, Kentaro, Tsujikawa, Keisuke
• Granted Patent: US 7,301,297 B2
• Time in Patent Office: Days
• US Class Current: 173/15
• CPC Class Codes: G05B 19/414 Structure of the control system, e.g. common controller or multiprocessor systems, interface to servo, programmable interface controller
• CPC Class Codes: G05B 2219/50216 Synchronize speed and position of several axis, spindles

Abstract

An “interval” in which the synchronization status between the movable axes subject to synchronous control is monitored, an equation between the movable axes in the “interval”, and an “allowable displacement” for the positional relationship obtained with this equation and the actual positional relationship are set in advance. The “start condition” and “termination condition” for synchronous status verification processing are set with the master position and the like. When the start condition for synchronous status verification processing is satisfied, it is detected whether or not the actual position and the position obtained with the equation are within the range of the allowable displacement based on the position of the movable axes. If not within the range of the allowable displacement, operation set as “operation to be executed when the allowable displacement is exceeded” is executed.

Claims

1. A synchronous control device synchronously controlling at least two movable axes, having one movable axis as a reference, and at least one other movable axis as a synchronized axis, comprising:

position detection means to constantly determine the position of each movable axis;

storage means to store information on the synchronous relationship between the positions of the movable axes subject to synchronous control, an allowable displacement, and an operation to be executed when the allowable displacement is exceeded;

displacement detection means to detect whether or not the relationship between the positions of the respective movable axes determined by said position detection means is within the range of said allowable displacement; and

abnormal time operation means to execute said operation to be executed when the allowable displacement is exceeded, when said displacement detection means detects that the relationship between the positions of the respective movable axes exceeds said allowable displacement.

2. The synchronous control device according to claim 1, wherein said storage means store at least one set of information on the synchronous relationship between the positions of the movable axes subject to synchronous control, and the allowable displacement,

said synchronous control device further comprises selection means to select one set of information of the sets of information stored in the storage means, and

said displacement detection means detects whether or not the relationship of the positions of the movable axes is within the range of the allowable displacement in the selected set of information.

3. The synchronous control device according to claim 1, wherein said synchronous control and verification of the synchronous relationship are executed in parallel.

4. The synchronous control device according to claim 3, wherein verification of the synchronous relationship executed in parallel with the synchronous control is executed by a signal input or program command.

5. A synchronous control device synchronously controlling at least two movable axes, having one movable axis as a reference, and at least one other movable axis as a synchronized axis, comprising:

position detection means to constantly determine the position of each movable axis;

storage means to store at least one set of information on the synchronous relationship between the positions of the movable axes subject to synchronous control, allowable displacement, a synchronous relationship verification start condition, a synchronous relationship verification termination condition, and an operation to be executed when the allowable displacement is exceeded;

selection means to select at least one set of information from the information stored in said storage means;

synchronous relationship verification start determination means to determine whether or not the verification start condition for synchronous relationship of the information selected with said selection means has been satisfied;

displacement detection means to detect whether or not the relationship between the positions of the respective movable axes determined by said position detection means is within the range of said allowable displacement after verification of the synchronous relationship has started with said synchronous relationship verification start determination means;

abnormal time operation means to execute said operation to be executed when the allowable displacement is exceeded, when said displacement detection means detects that the relationship between the positions of the respective movable axes exceeds said allowable displacement; and

synchronous relationship verification termination means to determine whether or not the termination condition for synchronous relationship verification is satisfied after verification of the synchronous relationship has started, and to terminate verification as to whether or not the synchronous relationship is in the normal status when the termination condition is satisfied.

6. The synchronous control device according to claim 5, wherein the synchronous control and verification of the synchronous relationship are executed in parallel.

7. The synchronous control device according to claim 6, wherein verification of the synchronous relationship executed in parallel with the synchronous control is executed by a signal input or program command.

8. The synchronous control device according to claim 5, wherein said synchronous relationship between the positions of the movable axes subject to synchronous control is composed of an interval and an equation of synchronous relationship between the movable axes in the interval.

9. The synchronous control device according to claim 8, wherein the number of the intervals set and stored is at least one.

10. The synchronous control device according to claim 5, wherein the synchronous relationship verification start condition and the synchronous relationship verification termination condition stored in the storage means specify at least one of conditions including relative or absolute time, instructed position of at least one axis, and signal status.

11. The synchronous control device according to claim 5, further comprising speed detection means to detect the speed of each movable axis, and the synchronous relationship verification start condition and the synchronous relationship verification termination condition stored in the storage means specify the speed detected with the speed detection means.

12. The synchronous control device according to claim 5, wherein any of actual movable axis position information, instructed position information, and time information, can be specified for the synchronous relationship between the positions of the movable axes stored in the storage means.

13. The synchronous control device according to claim 5, wherein the synchronous relationship of the positions of the movable axes stored in the storage means specifies a track by specifying the position information for each axis in the synchronous relationship with a sequence of points, and specifies an arbitrary expression between each sequence of points.

14. The synchronous control device according to claim 13, wherein the allowable displacement between each pair of points in the sequence of points is specified as distance information or an equation.

15. The synchronous control device according to claim 5, wherein operation with said abnormal time operation means is conducted by a program command, and a control program set and stored is executed based on this command.

16. The synchronous control device according to claim 5, wherein verification of the synchronous relationship can be halted by a signal or program during the verification of the synchronous relationship.