JPS6146845B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a home return confirmation method for a numerical control device.

Conventionally, there has been a method of returning to the origin of this type as shown in FIG.

In the figure, 1 is an information input medium (for example, paper tape), 2 is an input unit that reads input information from the information input medium 1, 3 is a control unit, 4 is a calculation unit, 5 is a controlled object such as a table of a machine tool, and 6 is a A detector such as a resolver for detecting the movement of a movable part of a machine tool, 7
is a dog for generating a deceleration signal.

Next, the origin return operation of this conventional method will be explained. A command to return to the origin is input from the input section 2 to the control section 3 through the information input medium 1. Then, the control section 3 determines that it is a return to the origin and controls the calculation section 4 to instruct fast forwarding. When the dog 7 is detected while the controlled object 5 is running in fast forward mode,
The control section 3 issues a command to the calculation section 4 to perform deceleration.
When the controlled object 5 finishes decelerating, the control section 3 issues a command to the calculation section 4 to operate at a constant slow speed. While the controlled object 5 is running at a slow speed, it leaves the deceleration dog 7.

Next, the control section 3 sends a positioning reference point to the calculation section 4 by detecting as a grid signal a pulse of a certain period generated based on the phase of each rotation of a detector such as a resolver. Controlled object 3 moves at a slow speed by a predetermined amount (according to the dock installation error)
stops at the origin.

FIG. 2 shows the speed pattern of the above operation, and when the origin return command or mode ZMD is output, the controlled object moves at a fast forward speed pattern ZPT. When the deceleration signal DOG is detected, the speed pattern
ZPT shifts to deceleration operation, and once deceleration is complete, it continues to move at a constant slow speed. When the grid signal GRS is detected after the deceleration signal DOG is no longer detected, the controlled object 3 reaches the positioning reference point, after which it moves at a slow speed by a predetermined amount (according to the dog installation error) and stops, completing the return-to-origin operation.

However, the speed of slow feed is determined by the grid signal GRS.
This is the speed at which the return to origin can be stopped within the allowable range of repeat accuracy when the detection of the return to origin is input to the control unit 3.

Since the conventional home return method was as described above, it takes a long time to run at slow speed, and for machines such as machining centers that require many home return operations, the disadvantage is that the machining cycle time becomes longer. It was hot. In order to improve this drawback, Japanese Patent Application Laid-Open No. 52-92080 has proposed a system in which slow feed during deceleration is omitted by employing a calculation method using a return control counter.

However, with this system, when the content of the return control counter reaches 0, it is determined that the return to the origin is apparently complete, so even if the content of the return control counter becomes 0, it is not the true origin. There was a drawback that it was not possible to confirm whether the restoration was completed or not.

This is because there is a backlash or the like in the controlled object, and the backlash or the like causes an error in the contents of the return control counter.

This invention constantly updates and stores the machine position from the machine origin (machine position storage unit), and when a command to return to the origin is received, the origin is positioned by fast forwarding based on the stored machine position data. The purpose is to provide a controllable device that can confirm whether or not the return to origin is complete.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 3, the same parts as the reference numerals in FIG. 1 indicate corresponding parts. Reference numeral 8 denotes a machine position storage section, which is cleared when the machine reaches its origin and constantly updates and stores the subsequent position of the machine.

Next, the operation will be explained. A command to return to the origin is input from the input section 2 to the control section 3 through the information input medium 1. Next, when the control section 3 determines that it is a return to the origin, it outputs the data in the machine position storage section 8 to the calculation section 4 as fast-forward positioning data. The controlled object 5 runs in fast forward motion, but since the control section 3 performs positioning control operations based on the data in the storage section 8, when the controlled object 5 reaches a certain position, the controlled object automatically decelerates. 5 stops. On the other hand, return to the origin can be confirmed based on the following conditions: the controlled object 5 steps on the dog 7 while moving and then leaves the dog 7, and the grid signal is detected when the controlled object 5 stops.

Figure 4 shows the operation pattern. When the origin return signal or mode ZMD is generated, the machine moves at a speed pattern ZPT using rapid traverse, and a high-speed traverse command is output until it reaches a predetermined position based on the positioning data in the storage section 8. , then automatically decelerates,
When the output of the positioning command is completed, the deceleration signal DOG disappears, and the signal matches the grid signal GRS, a coincidence signal COR is detected, and the return to origin is completed.

In other words, when the deceleration signal DOG disappears and the output of the positioning command ends, the coincidence signal COR cannot be detected unless the grid signal GRS is detected. This means that it can be detected that the machine is not accurately following the machining program and positioning is not performed.

In order to simplify the circuit, it is also possible to omit the dog on the machine side and check whether or not the return to origin is completed using only the machine position storage section 8 and the grid signal coming from the machine side.

As described above, according to the present invention, the machine position from the machine home is constantly updated and stored, and when a command to return to the home position is received, the machine position is returned to the home position by fast forwarding based on the stored machine position data. When a grid signal from the machine side is detected at the end of a positioning command (by detecting a matching signal), the completion of return to origin is confirmed, and when the grid signal is not detected. (by not being able to detect a matching signal)
Since this is a method to confirm that the return to origin is incomplete, it is possible to shorten the operation time for return to origin by driving the machine according to the relative movement position of the machine to the origin. Even if there is an error in the data of the machine position that has been made and the origin return operation is performed using the erroneous data, it becomes possible to confirm whether or not the origin return has been completed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory block diagram of a conventional origin return method using numerical control, FIG. 2 is a diagram showing the origin return operation pattern, FIG. 3 is an explanatory block diagram of the origin return method using numerical control according to the present invention, and FIG. The figure shows a pattern diagram of return to origin according to the present invention. 1 is an information input medium, 2 is an input section, 3 is a control section,
4 is a calculation section, 5 is a controlled object, 6 is a detector, 7 is a dog, and 8 is a machine position reading section. It should be noted that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A storage means for moving a movable controlled object in a predetermined direction and then returning the controlled object to its origin, which is cleared when the controlled object reaches its origin and thereafter updates and stores the relative movement position of the controlled object with respect to its origin. Based on the positioning data output from this means, a high-speed feed command is output until just before the home position, then a deceleration command is output to stop the controlled object at the home position, and at the end of the positioning command, the control A method for confirming return to origin for a numerical control device, characterized in that when a grid signal from a target side is detected, completion of return to origin is confirmed, and when the grid signal is not detected, return to origin is confirmed to be incomplete.