JPS59192488A - Compensator for output from load sensor in working device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a working device equipped with a load sensor that detects a reaction force acting on an operating section attached to an operating head of the working device. The present invention relates to a device for correcting.

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

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

<Purpose of the Invention> Therefore, the present invention automatically detects the gain change of the load sensor using the movement of the operation part, and automatically performs correction based on this, so that work can be carried out reliably. The purpose of this is to ensure that the

<Configuration of the Invention> FIG. 1 is an overall configuration diagram for clearly explaining the present invention. The displacement means (40) and (43) are, for example, the load sensor 1
Based on the output signal of 8, the gripping claw (operation section) 12 is moved in the closing direction until a certain initial load is applied to the load sensor 18, and then the servo is activated to further move the gripping claw 12 in the closing direction. Rotate the motor S M tJ by a certain amount.

The detection means (41) and (44) detect the output fo of the load sensor 18 when the initial load can be applied and the output after a certain amount of rotation of the servo motor SMU, and the calculation means (45) detects the output fo after the servo motor SMU has rotated by a certain amount. The load sensor 1 is calculated from the pair of output values and the amount of rotation of the servo motor SMU, that is, the amount of increase in the load applied to the load sensor 18.
The correction means (52) corrects the output value of the load sensor 18 according to the change amount calculated by the calculation means (45).

1. <Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 2, reference numeral 10 indicates a work head 10 equipped with a pair of gripping claws 12, 12. This work head 10 is supported movably in three-dimensional directions by a concave support mechanism, and is driven by servo motors SMX, SMY, SMZ. It is now moved by

The gripping claws 12 are guided so as to be horizontally movable on a support portion 11 integrally formed at the lower end of the working head 10, and are supported horizontally at both ends of a screw shaft 13 having reverse threads at both ends. Each part is screwed together. This helical shaft 13 is a rotating shaft 1 that vertically passes through the center of the work head 10 via bevel gears 15a and 15b.
6, and this rotating shaft 16 is connected to a strain cylinder 17.
The output shaft of the servo motor SMU is connected to the output shaft of the servo motor SMU.

A load sensor 18 made of a semiconductor strain gauge or the like is attached to the outer periphery of the strain tube 17 to indirectly detect the reaction force acting on the gripping claw 12 depending on the amount of strain in the strain tube 17. The output signal is transmitted to the work head 10 side via the slip ring mechanism 19.

Further, the support portion 11 is provided with an origin stopper 14 for regulating the closed end of the gripping claw 12.

Next, to explain the configuration of the control circuit, the central processing unit 31 in the numerical control device 30 is configured by a microprocessor, and this central processing unit 31 includes a memory 32,
Data input device 33, interface IF1. IF2 is connected, and the ink face IFI has a servo motor S.
MX, SMY.

Drive unit D that drives SMZ and SMU respectively
UX, DUY, DUZ, and DUU are connected. In addition, the output of the load sensor 18 is
9 to the amplifier circuit 20, and this amplifier circuit 20
The output is supplied to the central processing unit 31 via the AD converter 21 and interface TF2.

Next, the operation of the central processing unit 31 will be explained. Before starting the work program input in advance, the central processing unit 31 executes the program shown in FIG. Performs change detection processing. That is, the central processing unit 31 &t(40)
By repeating the processes from (42) to (42), the gripping claw 12 comes into contact with the stopper 14 fixed to the working belly button +"IO, and the output F of the load sensor 18 reaches the predetermined initial load fo, as shown in FIG. Drive Unisol l-D U U until it shows
When it detects that the initial load fo has been applied to the gripping claws 12 (42), the drive unit DUU sends a pulse to further close the gripping claws 12 by a certain minute amount Δ. 43), and then read the output F of the load sensor Il-18 again (44).
.

Then, by calculating f-fo, the output change amount Δ
In addition to calculating f, the deviation Δfε between this output change amount Δf and the reference change amount Δfs measured and stored at the time of assembling the load sensor 18 is calculated by calculating Δfs - Δf (45), and this is stored in the change amount register VR. (46), and returns to the main routine of the concave road.

On the other hand, when performing normal work, the central processing unit 316- executes the process shown in FIG. 4 to confirm that the article W is being held. That is, first of all, a pulse is supplied to the drive unit DUU in order to close the gripping claw 12 by a constant M (50), and then the output value f of the load sensor 18 is read (51), and M-f+(Δfε・X The correction value f' is approximately calculated using the correction formula: /Δl). In addition, in the above formula, X is the number of pulses distributed to the servomorph SMU after the gripping claw 12 contacts the article W, and as shown in FIG. 5, it is calculated by the correction formula of the above formula. The correction value f' becomes the output value of the load sensor 18 when no characteristic change occurs.

Then, it is determined whether or not this correction value f' exceeds the set value fs (53), and if it is determined that it exceeds the set value fS, the process moves to the concave road head movement routine and performs the predetermined work. If it is determined that the load has not exceeded the set value fS, the process returns to (50) and processes (50) to (52) are performed again until the gripping claws 12 grip the article W with the set load rs.ゝ1 Repeat the same operation below.

In the above embodiment, a pressing reaction force is applied to the gripping claws 12 by pressing the gripping claws 12 against the stopper 14 provided on the workpiece 10, but this is shown by the two-dot chain line in FIG. Attach the fixed block 23 to the fixed part as shown,
A pressing reaction force may be applied to the gripping claws 12 by pressing the gripping claws 12 against the gripping claws 23 .

Further, the present invention can be applied to output correction of a load sensor for detecting press-in force in a press-fitting device and a load sensor for detecting tightening torque in a nut runner.

<Effects of the Invention> As described above, in the present invention, a predetermined load is applied to the load sensor by bringing the operating part on the work head into contact with the contact part, and the load applied to the load sensor is The configuration is configured to detect the amount of change in the output of the load sensor with respect to the change in size, derive the amount of change in the gain of the load sensor, and correct the output of the load sensor based on this, so the change in the gain of the load sensor can be corrected. This has the advantage that it can be automatically detected and corrected, and that gripping work etc. using a working device can be performed reliably.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram for clearly demonstrating the present invention, Figures 2-
FIG. 5 shows an embodiment of the present invention, FIG. 2 is a sectional view of the working head and a block diagram showing the control circuit, and FIGS. 3 and 4 are the central processing unit in FIG. 2. 3
The flow chart shown in FIG.
3 is a diagram showing the relationship between the displacement of the load sensor 18 and the output of the load sensor 18. FIG. 10... Working head, 12... Gripping claw, 13...
Screw shaft, 14... Stopper, 17... Strain tube, 18
...Load sensor, 31...Central processing unit, DUU・
...Drive unit, SMU...Servomorph. Patent applicant Toyota Machinery Co., Ltd. 9- Figure 4

Claims (1)

[Claims] (1) In a working device equipped with a load sensor that detects a reaction force acting on an operating portion attached to an operating head of the working device, a displacement means for displacing the operating portion in a direction to press the operating portion against the contact portion; , a detection means for detecting the output of the load sensor at the time when the operation section contacts the contact section and at the time when the load applied to the operation section increases by a certain amount from the time of this contact; It is characterized by comprising a calculation means for calculating the amount of change in characteristics of the load sensor based on a pair of detected values, and a correction means for correcting the output of the load sensor according to the amount of change calculated by the calculation means. An output correction device for a load sensor in a working device.