JPH02145287A - Robot for engaging work - Google Patents

Abstract

PURPOSE:To reduce defective products dusts existing inside a device in the products to be delivered by providing a detection means detecting that the output of a power sensing sensor under engaging work becomes in the state of the abnormal output different from the output to be output during a normal engaging work. CONSTITUTION:A means 38 storing the output hysteresis of a power sensing sensor 12 under normal engaging work and a comparing means 39 comparing the output of the power sensing sensor 12 under engaging work and the normal output stored in a memory means are provided. As the result of the comparison by this comparing means 39, the abnormal output state different from the output to be output during the normal engaging work having become, i.e. the generation of dusts under engaging work is detected. Consequently, defective products can be detected at the engaging work time and the obstruction generated after the test at the product completion time and the delivery to users can be prevented.

Description

[Detailed Description of the Invention] [Summary] A robot equipped with a force sensor and performing a fitting operation of fitting a member held by a hand into a mating member 7) Parts of a magnetic disk drive that are particularly sensitive to dust. We aim to provide a mating robot that can detect dust generated by chips and bites during mating work, and reduce the number of products that cause hend crashes. The device is configured to include a detection means for detecting that the output of the force sensor is in an abnormal output state different from the output that should be output during normal mating work, and to detect the generation of dust during mating work. The detection means includes means for storing an output history of the force sensor during the normal fitting operation, and a comparison means for comparing the output of the force sensor during the fitting operation with the normal output stored in the storage means. and is configured to detect that an abnormality detection state has occurred when the output of the force sensor during the fitting operation differs from the output of the storage means by a predetermined value or more. Alternatively, it has two abnormality detection reference signals, one at the start of mating and one during subsequent mating work, and the output of the abnormality detection means and the output sensor of the force sensor is adjusted according to the state of the mating work. By comparison, it is configured to detect that the abnormality detection state is different from the output that should be output during the normal fitting operation.

[Industrial Field of Application] The present invention relates to a robot for assembling precision equipment such as a magnetic disk device that is sensitive to dust, and particularly to a robot for fitting parts together.

Advances in industrial robots have led to automation of assembly work,
Their work movements have become more accurate and faster, and industrial robots are now being used to assemble precision equipment.

(Prior Art) As shown in FIG. 3, a conventionally used fitting robot holds one of the members to be fitted in the hand 13 and moves the said member onto the mating member by horizontally moving the arms 15 and 16. Then, the arm 11 is vertically lowered to fit the member into the mating member. 12 is a force sensor that detects the external force applied to the hand, and the robot control unit controls the arm 11 when both members are fitted. When the arm 11 stops descending, that is, when the force sensor 12 detects a predetermined force, the arm 11
stop the descent.

In recent years, positioning control has become more precise and compliance control has led to the use of robots to assemble precision equipment.

Compliance control is a method of controlling the robot to absorb the positional displacement between a certain member and its counterpart member, and uses a force sensor to detect external force applied to the hand and move the hand in a direction where the external force is no longer applied. It is something.

To explain the fitting operation using such a robot, the fitting operation of a disk disk and a spindle shaft in the assembly operation of a magnetic disk device will be explained as an example. As shown in FIG. 4, the conventional fitting operation requires high precision with a clearance of about 20 to 90 μm. As shown in FIG. , and lower the arm 11 toward the spindle shaft 92 of the magnetic disk device being assembled.

Figure 5 shows force sensor 1 when mating work is performed normally.
2 in the Z-axis direction. The arm 11 stops descending by force control, for example, when a specified force of 2 kgf is detected. At this time, compliance control in the Z-axis direction is not performed until a specified force is detected. Additionally, due to excessive positional deviation or inclination of the spindle shaft 92, the hand may stop due to force control before the mating work is normally completed, but this can be done by monitoring the work time and stopping the work sooner than a predetermined time. It is assumed that some abnormality has occurred when this happens. Further, when the position at which the hand stops does not reach a predetermined position, it may be assumed that some abnormality has occurred.

FIG. 8 is an explanation of compliance control.

If the position of the disk disk 91 is misaligned with respect to the spindle shaft 92, as the arm 11 is lowered, the disk disk 91 will come into contact with the chamfered portion 95 of the spindle shaft 92. This direction is detected and the hand is moved in a direction where no external force is applied. Normally, the placement position will inevitably vary depending on the product, but if it is within the range of the chamfered part 95 of the spindle shaft 92,
Fitting work can be performed.

(Intelligence problem that the invention attempts to solve) However, in the mating work performed by a robot, the proportion of products that cause head crashes was higher than in the conventional manual mating work. When the output of a force sensor during the fitting operation is recorded by a robot, an output as shown in FIG. 6 may be detected. Probably, as shown in FIG. 9, there is a very small protrusion 96 at the fitting part of the spindle shaft 92, and the disc plate 91 scrapes off the protrusion 96. This scraped protrusion 9
If 6 remains in the device, it becomes dust and becomes a cause of serious accidents such as head crashes.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fitting robot that can detect the generation of dust due to chipping or biting during fitting operations, and can reduce the number of products that cause head crashes.

[Means to solve the problem]

In order to achieve the above object, a detection means is provided to detect when the output of the force sensor during the mating operation is in an abnormal output state different from the output that should be output during the normal mating operation. The system is configured to detect dust generation during collaborative work.

The detection means includes means for storing the output history of the force sensor during the normal fitting operation, and comparison means for comparing the output of the force sensor during the fitting operation with the normal output stored in the storage means. , the output of the force sensor during the mating operation is
When the output of the storage means differs by more than a predetermined value,
The configuration is configured to detect that an abnormality detection state has occurred.

Alternatively, it has two abnormality detection reference signals, one at the start of mating and one during subsequent mating work, and the output of the abnormality detection means and the output sensor of the force sensor is adjusted according to the state of the mating work. By comparison, it is configured to detect that the abnormality detection state is different from the output that should be output during the normal fitting operation.

[Function] Force control of the output of the force sensor II! In addition to being used for compliance control and the like, the output of the force sensor is used to detect when a protrusion of a mating member is scraped off by a mating member. Therefore, defective products can be detected during the fitting operation, and failures that occur during testing when the product is completed or after it is shipped to the user can be prevented.

〔Example〕

FIG. 1 is a block diagram of an embodiment of a fitting robot according to the present invention. To simplify the explanation, the robot has three degrees of freedom in the X, Y, and Z axes, and has a hand 13 in the Z-axis direction.
The mating work shall be performed by moving the It is also assumed that the force sensor 12 detects force in the three axial directions of the X, Y, and Z axes.

In the figure, 40 is a central processing unit, which sends an I command value to the controller 20 of the robot. It is assumed that the inside of the controller 20 is composed of a drive section 21, a force control section 22, and a position control section 23. Drive section 21, force control section 22
, the position control unit 23 is composed of three components in the XYZ axis directions.

The force control unit 22 drives the hand 13 with a force specified by the central processing unit 40, and performs control to approach the specified value by receiving feedback of the output of the force sensor 12. The force control unit 22 also performs compliance control based on the output of the force sensor 12.

The position control unit 23 receives a position command from the central processing unit 40 and controls the movement to a specified position. Position information is also fed back from a position sensor (not shown) attached to the drive unit 21, so that the current position is determined as the specified position. Control is performed so that it approaches . In addition, speed control is performed by the central processing unit 40.
This is done by adding the specified speed value from the input value to the value input to the drive unit 21.

In the figure, 3rd is a history part that stores the output value of the force sensor at each point in time during the fitting operation, and 39 is the output value of the force sensor that should be obtained at each point in time during normal operation and the allowable value at that point. This is a comparison value storage unit that stores the output width. During the fitting work, the output value of the force sensor 12 is stored in the history section 38, and after the work is finished, the central processing unit 40 compares the values in the history section 38 and the comparison value storage section 39, and the value in the history section 38 is If the value in the comparison value storage section 39 is within the specified range, it is considered normal; otherwise, it is considered abnormal. Alternatively, the output value of the force sensor 12 and the value of the comparison value storage section 39 may be compared in real time without providing the force sensor output history section 38.

FIG. 2 is a block diagram of another embodiment according to the invention. The operation of the controller is similar to the above embodiment. In the figure, 30 is means for detecting the generation of dust during the fitting operation, and when the generation of dust is detected, it reports an abnormality to the central processing unit. The abnormality detection means 30 includes a comparison value generator 31 and a comparator 32
, SR type rough flip-flop 33 negator 34, AND 3
Consists of 5.

The comparison value generator 31 operates according to instructions from the central processing unit 40.
A waveform as shown in FIG. 7 is output. This comparison value is determined by measuring the maximum value of the needle waveform when dust is generated in advance.
In Figure 0, which is set based on this, the comparison value is a little high at the start of mating, but when the chamfered part of the disk disc and spindle shaft come into contact during the mating process, a slightly high output is temporarily obtained, and the chamfered A high comparison value is set because it is less likely to cause chewing or biting.

The abnormality detection means 30 detects that the output of the force sensor 12 exceeds a predetermined comparison value, and detects that the output of the force sensor 12 returns to below the predetermined comparison value, thereby detecting the generation of dust. are doing. In other words, this is distinguished from the case where the output of the force sensor 2 suddenly reaches the specified value when the pushing operation is completed.

The detailed operation of the abnormality detection means 30 will be explained below.

The comparator 32 outputs the output of the comparison value generator 831 and the force sensor 1.
When the output of the force sensor 12 exceeds the comparison value, the output of the comparator 32 becomes 1. At the same time, the output of the flip-flop 33 changes from 0 to 1.

Next, when the output of the force sensor 12 returns below the comparison value, the output of the comparator 32 becomes 0 and the output of the negator 34 becomes 1. At this time, the output of the logical multiplier 35 becomes 1, and this is sent to the central processing unit 40 to report the abnormality.

〔Effect of the invention〕

As explained above, in the present invention, even if a robot performs the fitting work of precision equipment that is sensitive to dust, such as the fitting work of the disk disk and spindle shaft of a magnetic disk drive, dust will not be generated during the work. Since the occurrence can be detected, it is possible to reduce the number of defective products shipped due to the presence of dust inside the device.

In addition, manual work is not completely free of dust, and while human hands may not be able to handle the slightest bites or bites, the accuracy of the force sensor in the mating work performed by robots can prevent the slightest bites and bites. It is possible to detect.

Furthermore, it is possible to detect the generation of dust during work, and by intensively performing cleaning work such as varnishing on the product, it is possible to ship the product as a normal product.

existing spin In the figure, 12 It is a figure showing a dollar axis.

...Force sensor Figure 4 is a diagram explaining the fitting work of the disc and spindle, Figure 5 is a diagram of the output waveform of the force sensor during normal operation, and Figure 6 is a diagram showing the robot performing the work. FIG. 7 is a waveform diagram showing the comparison value with the output of the force sensor when the force sensor occurs. FIG. 8 is a diagram explaining compliance control. FIG. -Zoro to the big culprit lawsuit - 1st group (91) Spear figure Kayazu Kimitsu - - Large & 4 rows 2nd bite - 1 mouth figure Samurai - Z) Concave 6th Concave Kaya 2

Claims (1)

[Scope of Claims] [1] In a robot that is equipped with a force sensor that detects an external force applied to the hand and performs a fitting operation in which a member held by the hand is fitted into a mating member, the force sensor during the fitting operation The present invention is characterized in that it includes a detection means for detecting that the output is in an abnormal output state different from the output that should be output during normal mating work, and detects the generation of dust during mating work. A mating work robot. [2] The detection means includes means for storing the output history of the force sensor during the normal fitting operation, and a comparison means for comparing the output of the force sensor during the fitting operation with the normal output stored in the storage means. means, and detects that an abnormality detection state has occurred when the output of the force sensor during the fitting operation differs from the output of the storage means by a predetermined value or more. The fitting work robot according to claim 1. [3] The detection means has two abnormality detection reference signals, one at the start of fitting and one during the subsequent fitting operation, and depending on the state of the fitting operation, the abnormality detection means and the force sensor 2. The fitting work robot according to claim 1, wherein an abnormality detection state different from an output that should be output during normal fitting work is detected by comparing the output of the output sensor.