JPH057136B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention checks or calibrates a load sensor that detects an operation reaction force acting on an operation part such as a gripping claw attached to a work head of a work device. It is related to the device.

<Prior art> A work device equipped with a gripping claw is provided with a load sensor to detect the reaction force acting on the gripping claw, and the output of this load sensor is used to confirm the gripping of an article, control the gripping force, etc. Therefore, if the characteristics of the load sensor change or break down, grip confirmation, etc., cannot be performed accurately.

However, in conventional work devices, such changes in the characteristics of the load sensor cannot be automatically detected, and there is a risk that inaccurate work may be performed due to changes in the characteristics of the load sensor.

<Object of the Invention> Therefore, an object of the present invention is to automatically check or calibrate a load sensor based on the force generated by a reference force generating element such as a master spring. be.

<Configuration of the Invention> FIG. 1 is an overall configuration diagram for clearly explaining the present invention. an engaging member 61a that is supported on a support member 53 that is movable relative to the work head 11 and engages with the operating section by moving relative to the work head 11;
61b, and a master spring 63 which is a reference force generating element that is connected to the engaging members 61a, 61b and applies a reference pressing force to the engaging members 61a, 61b.
After the gripping claws 12 are positioned so as to engage with the engaging members 61a and 61b, the displacement applying means 1 is enabled and the gripping claws 12 are rotated by the rotation of the servo motor SMU.
is moved a certain amount from its original position, and the master spring 63 is deflected by a certain amount.

The check calibration means 2 determines whether or not the position of the gripping claw 12 or the output of the load sensor 31 is within a predetermined range when either the position of the gripping claw 12 or the output of the load sensor 31 is set to a constant value, and if the other is within a predetermined range, the deviation is calculated. The value is calculated and corrected, and if the value is not within a predetermined range, a check calibration process is performed that outputs an abnormal signal ABN.

<Examples> Examples of the present invention will be described below based on the drawings. In FIG. 2, reference numeral 10 denotes a support head to which various types of work heads 11 can be selectively attached.
It is guided and supported by a and 13b so as to be able to move up and down relative to the transverse feed table 14, and is moved by a servo motor 16 via a feed screw 15. Further, a cross beam 21 is disposed astride a work table 20 that is guided so as to be movable on the bed 18 in a direction perpendicular to the plane of the paper and is moved by a servo motor 19. The cross beam 21 is movably guided on the cross beam 21.
Positioning is possible by a servo motor 22 attached to the end of the servo motor 22. Further, at the left end of the cross beam 21, a working head storage magazine 23 for storing a plurality of working heads 11 and a head changing device 24 equipped with a changing arm are provided.
The work head 11 in the hand storage magazine 23 and the work head 11 on the support head 10 are exchanged with the cross feed table 14 moved to the left end.

Of the work heads 11, the work head for gripping and transferring articles is connected to the support head 1 as shown in FIG.
It has a shank part 11a that fits into a holding hole 10a drilled in the lower end of the shank part 11a, and a pawl guide part 11b integrally formed at the tip of this shank part 11a includes:
A screw shaft 25 having opposite male threads carved in opposite directions is supported at the center and extends in a direction perpendicular to the axis of the shank portion 11a. are screwed together. Further, a drive shaft 27 having an engagement piece 26 at the upper end is supported on the axis of the shank portion 11a, and the drive shaft 27 and the screw shaft 25 are connected to a pair of bevel gears 28a, 28.
connected by b.

On the other hand, a notch mechanism 35 for maintaining the attached state of the working head 11 is provided at the lower cylindrical portion of the support head 10, and a notch mechanism 35 for maintaining the attached state of the working head 11 is provided at the upper rectangular portion.
A drive mechanism 36 for rotating the engagement piece 26 is provided. This drive mechanism 36 includes a worm wheel 40 that is rotatably mounted on an extension of the axis of the holding hole 10a and rotated by a servo motor 38 that is mounted on the outer wall of the work head 10 via a worm 37; A rotary shaft 41 extends vertically through the axial center of the worm wheel 40 and is allowed to move only in the vertical direction with respect to the worm wheel 40 due to spline engagement.A downward pressing force is applied to the rotary shaft 41. When the working head 11 is attached to the support head 10, the engaging teeth formed at the lower end of the rotating shaft 41 engage with the engaging teeth of the engaging piece 26.

A position detector 43 for detecting the amount of rotation of the rotating shaft 41 is attached to the upper end of the support head 10. This position detector 43 is an incremental type position detector, and the position detector 43 is an incremental type position detector.
Each time the operating section is displaced by a certain distance, a positive or negative pulse is generated depending on the direction of displacement, and the pulse output from the position detector 43 is supplied to a position detection counter 45 in a numerical control device 80, which will be described later. The position of the operating section of the work head 11 can be detected.

Further, a flexible portion 12a is formed at the reference portion of one of the gripping claws 12, and a load sensor 31, which is a semiconductor strain gauge or the like, is mounted on the flexible portion 12a to detect the operational reaction force acting on the gripping claw 12. is installed,
The output of this load sensor 31 is connected to the connector 3 attached to the work head 11 and the support head 10.
2, 33 to the support head 10 side,
It is designed to be supplied to the input of the AD conversion circuit 46 in the numerical control device 80.

Furthermore, on the left side of the workbench 20 in FIG.
Mastering unit 5 corresponding to each of 1.
A mastering device 51 including 0a to 50n is provided. That is, the support body 52 is fixed to the column 21a that supports the cross beam 21.
A rotary disk 53 that can be rotated and indexed in a horizontal plane is supported, and mastering units 50a to 50n are attached to the outer edge of the rotary disk 53 at equal opening intervals. And inside the support body 52,
An indexing mechanism for positioning one of the mastering units 50a to 50n at an indexed position within the work area by rotationally indexing the rotary disk 53 is built-in.

The mastering units 50a to 50n have different types depending on the type of work, such as object gripping, screw tightening, etc., and as shown in FIG.
The gripping mastering unit 50a has an engaging portion 61 that can be engaged with the gripping claw 12 of the work head 11.
A pair of movable bodies 62, 62 formed with the movable bodies 62, 61b are movably guided and supported by the unit base 60, and a master spring 6 is inserted between the pair of movable bodies 62, 62.
3 are arranged.

Further, the mastering unit 50n for screw tightening work has a rotating shaft 72 equipped with an engaging portion 71 that can engage with the screw tightening socket of the work head 11 for screw tightening work supported on the unit base 70, and this rotating shaft A master spring 73 is disposed between a rack 74 that engages with teeth 72a formed in the spring 72 and a cap 75 that is fixed to the unit base.

Next, to explain the control circuit, the central processing unit 81 in the numerical control device 80 is constituted by a microprocessor, and this central processing unit 81 includes a memory 82, a data input device 83, and interfaces 84a and 84b. Servo motors 19, 16, 38,
Drive unit DUY that drives each of 22,
DUZ, DUU, and DUX are connected, and the position detection counter 45 and the output of the AD conversion circuit 46 are connected to the interface 84b.

The memory 82 is provided with a numerical control data area NCDA that stores numerical control programs for performing various assembly operations, and stores a plurality of sets of numerical control programs corresponding to the types of articles to be worked on. Each numerical control program has a fifth
As shown in the figure, a working head 1 suitable for the working article
1 to the supporting head 10 are programmed into the first block N001, and when this data is read, the currently attached working head 11 is returned to the working head storage magazine 23. Then, the work head 11 to be used next is attached to the support head 10.

After this, the mastering units 50a to 50 of the mastering device 51 are controlled by the command data of U01 programmed in block N002.
Among n, work head 1 attached to support head 10
After the one corresponding to 1 is determined, block No.
Mastering units 50a to 50n with the support head 10 lowered and the operating section of the work head 11 indexed according to the G00 Z-15000 program of 03
is positioned so as to be able to engage with the engaging portion of.

Further, when the program M51 programmed in the subsequent block N004 is read out, the central processing unit 81 executes the detector check process shown in FIG.

That is, first, a pulse is supplied to the drive unit DUU in order to close the operation part of the working head 11 mounted on the support head 10, in this case the gripping claw 12, by a certain amount L from the original position (90),
After this, the output value of the load sensor 31 is read (91).
Then, it is determined whether or not this read value F is within the range of A _L to A _H , which is considered to be the usable limit range (92),
If it is not within this range, display an abnormality (93),
Stop working.

On the other hand, if the read value F is within the range of A _L to A _H , the deviation ΔF between the read value F and the reference value F _O is calculated (94), and this is used as the correction value. Store (95) and complete the calibration process (96).
As a result, when performing gripping force control etc., the output value of the load sensor 31 is corrected with the stored correction value,
Accurate operating force can be detected.

As shown in FIG. 7, the rate of change in the repulsive force of the master spring with respect to the amount of movement of the gripping pawl 12 after the gripping pawl 12 comes into contact with the engaging portions 61a, 61b is relatively small. 12
Even if the position of the load sensor 31 varies to some extent, a constant reference force can be generated accurately, and an abnormality in the load sensor 31 can be determined with high precision.

In the above embodiment, a characteristic change is detected when the output of the load sensor deviates from a predetermined range after moving the operation part of the work head by a certain amount, but if the output value of the load sensor is A characteristic change may be detected by detecting that the position of the operating section deviates from the reference position by more than an allowable value when the operating section is moved until a constant value is reached.

<Effects of the Invention> As described above, the present invention includes an engaging member that is supported on a support member that is movable relative to the work head and engages with the operating portion by moving relative to the work head; A master unit is provided which includes a reference force generating element connected to the engaging member, a displacement imparting means for relatively displacing the operating portion, and a actuated after relative displacement of the operating section by the displacement applying means, and when either the position of the operating section or the output of the load sensor is set to a constant value in the relationship between the position of the operating section and the output of the load sensor; A check calibration means is provided which determines whether or not the other is within a predetermined range, and if it is within the predetermined range, calculates and corrects the deviation, and if it is not within the predetermined range, outputs an abnormal signal. It becomes possible to automatically check or calibrate changes in the characteristics of the load sensor, which has the advantage of greatly improving the reliability of the working device.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram for clearly demonstrating the present invention.
2 to 7 show embodiments of the present invention,
FIG. 2 is a diagram showing the overall configuration of the working device together with a block diagram showing the control circuit, FIG. 3 is a vertical sectional view showing the configuration of the support head 10 and the working head 11 in FIG. 2, and FIG. A partially enlarged view showing the configuration of master units 50a to 50n in FIG. 2,
Figure 5 is the numerical control data area in Figure 2.
FIG. 6 is a flowchart showing the operation of the numerical control device 80 in FIG. 2, and FIG. 7 is a diagram showing the numerical control program stored in the NCDA.
4 is a graph showing a change in the output of the AD conversion circuit 46 with respect to movement of . 10...Support head, 11...Working head, 1
2...Gripping claw, 31...Load sensor, 50a-5
0n... Master unit, 62, 72... Engaging portion, 63, 73... Master spring, 80...
Numerical control device, 81...Central processing unit, 82...
memory.

Claims (1)

[Claims] 1. In a working device that has a load sensor that detects an operation reaction force acting on an operating part such as a gripping claw attached to a working head of the working device, the device is supported on a support member that is movable relative to the working head and is used for work. A master unit is provided which includes an engaging member that engages with the operating section by relative movement with the head, and a reference force generating element connected to this engaging member, and a master unit that relatively displaces the operating section. The applying means operates after the relative displacement of the operating section by the displacement applying means in a state where the engaging member is engaged with the operating section, and in the relationship between the position of the operating section and the output of the load sensor. When either the position of the operation unit or the output of the load sensor is set to a constant value, it is determined whether the other is within a predetermined range, and if it is within the predetermined range, the deviation is calculated and corrected, and 1. A check or calibration device for a load sensor in a working device, characterized in that it is provided with a check calibration means for outputting an abnormal signal if the load sensor is not within the range of .