JPH0557667A - Weighing device - Google Patents

Abstract

PURPOSE:To weigh a measured object in the interposed state. CONSTITUTION:A robot hand 1 is provided with two vertical pairs of load sensors 6a, 6b opposedly disposed in the mutually advancing/receding state. A weighed object 4 is thereby held/released from the upper and lower directions by these pairs of load sensors 6a, 6b, and the difference signal of the respective output signals of these load sensors 6a, 6b is outputted from an arithmetic processing means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weight measuring device used in an industrial robot or the like for measuring the weight of an object to be measured.

[0002]

2. Description of the Related Art Conventionally, when measuring the weight of an object to be measured held by a robot hand of an industrial robot, the robot hand is moved onto a scale whose position is fixed and released to release the object to be measured. It was placed on a scale and weighed.

[0003]

However, as described above, there is a problem that the step of moving the robot hand to the position of the scale and the step of releasing the robot hand at the position of the scale are required. It was also necessary to provide a place to install the scale. Further, when sorting the objects to be measured by weight, after placing the objects to be measured on the balance in the above process, classify by the weight value and place them in the designated place, the objects to be measured with the robot hand. The number of steps for pinching again and moving it to the designated place is further increased.

Another conventional example is Japanese Patent Laid-Open No. 63-29.
As shown in Japanese Patent No. 5226, some robot hands have a weight measuring means attached thereto. In this conventional example, the step of moving the robot hand to the position of the scale is unnecessary,
At the time of weight measurement, it is necessary to release the held object to be measured as in the above-mentioned conventional example. Therefore, an object of the present invention is to provide a weight measuring device capable of performing weight measurement while holding an object to be measured, and not particularly requiring a place for installing a scale.

[0005]

According to the weight measuring apparatus of the present invention, a pair of upper and lower load sensors are arranged on a robot hand so as to be capable of advancing and retreating with respect to each other. To be able to release
The arithmetic processing means outputs a difference signal between the output signals of the pair of load sensors.

[0006]

When the object to be measured is clamped by a pair of upper and lower load sensors and the object to be measured is stationary, the weight of the object to be measured is from the weight value of the lower load sensor to the weight value of the upper load sensor. Is given as less than. Therefore, by outputting the difference signal between the output signals of the pair of load sensors by the arithmetic processing means, the weight value of the object to be measured can be obtained while it is held.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A weight measuring device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a robot hand of an industrial robot for taking out a molded product, and a weight measuring device is used for this robot. Robot hand 1
Is rotatably attached to the tip of the arm 2 (a rotation mechanism is not shown), and is movable in three dimensions along with the movement of the arm 2 to take out and move the DUT 4 as a molded product. I do. Specifically, the robot hand 1 is provided with two pairs of load sensors 6a and 6b which are arranged on the upper and lower ends of a vertical base plate 5 so as to be capable of advancing and retreating with respect to each other and which can clamp and release the DUT 4 from the vertical direction. ing. The load sensor 6a (6b) includes the load cell 7a (7b) and the DUT 4
And a pressure receiving portion 8a (8b) for contacting with and holding the movable portion of the movable portion of the extendable actuator 9. The actuator 9 is composed of an air cylinder, a solenoid, and the like. In addition, a pair of load sensors 6a, 6
The difference signal between the output signals of b is output by the arithmetic processing means as shown in FIG. That is, the electric signals from the load cells 7a and 7b of the load sensors 6a and 6b are transferred to the preamplifier 10 and the analog-digital converter 11 respectively.
After being processed by the input signal processing section 12, the arithmetic processing section 13 converts the weight value of the DUT 4 into a weight value, and the data output section 14 transmits the weight value to an external host computer or printer. Reference numeral 15 is a control unit which controls the entire robot, and controls the actuator 9 and the like of the robot hand 1 and the output timing of the data output unit 14.

Next, the operation will be described. Arm 2
When the robot hand 1 moves to the position of the object to be measured 4 due to the movement of the robot, the robot hand 1 is appropriately rotated according to the state of the object to be measured 4, the actuators 9 are extended, and the load sensors 6a and 6b move forward. , Its pressure receiving portion 8a,
The object to be measured 4 is clamped by 8b. Along with this, electric signals from the load cells 7a and 7b of the load sensors 6a and 6b pass through the preamplifier 10 and the analog-digital converter 11 of the input signal processing unit 12 as shown by arrows in FIG.
It is guided to the arithmetic processing unit 13. Here, assuming that the DUT 4 is stationary with the base plate 5 in a vertical state, that is, with the pair of load sensors 6a and 6b in the vertical direction,
The weight of the DUT 4 is given as the sum of the weight values of the lower load cells 7b and 7b minus the sum of the weight values of the upper load cells 7a and 7a. Therefore, the arithmetic processing unit 13 obtains the weight value of the DUT 4 by outputting the difference signal between the output signals of the load sensors 6a and 6b sent through the input signal processing unit 12. This weight value is transmitted to the external device through the data output unit 14 as described above. After the weight of the object to be measured 4 is measured in this way, when sorting by the weight value, the arm 2 is moved to move the object to be measured 4 to the release position, and the robot hand 1 is rotated 90 degrees. The object to be measured 4 is released by moving it to bring it into a downward horizontal state and contracting the actuator 9.

As described above, in this embodiment, the weight value can be obtained by sandwiching the object to be measured 4 which is a molded product, so that the object to be measured 4 is moved to a designated location, for example. The weight value can be measured at the same time in the process. Therefore, there is an advantage that the robot operates extremely smoothly. In this embodiment, the weight measuring device is used for the industrial robot that takes out the molded product, but the robot may be used for other purposes. Further, in FIG. 1, two pairs of load sensors 6a and 6b are provided, but the configuration may be one pair or three or more pairs.

[0010]

According to the weight measuring device of the present invention, the arithmetic processing means outputs the difference signal between the output signals of the pair of load sensors to obtain the weight value of the object to be measured while it is clamped. You can Therefore, it is not necessary to provide a place for installing the scale, which saves space, as compared with the conventional case.
Further, along with this, the step of moving the robot hand to the place where the scale is installed and the step of releasing the clamped object to be measured are unnecessary, and the measurement can be performed efficiently. Further, when sorting the objects to be measured according to the weight value, in addition to the above steps, there is no need for a step of holding the object to be measured again and moving the robot hand from the installation location of the scale to the designated location classified. It is even more effective.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example in which a weight measuring device according to an embodiment of the present invention is used in a molded product take-out robot.

FIG. 2 is a block diagram of arithmetic processing means.

[Explanation of symbols]

 1 Robot hand 4 DUT 6a, 6b Load sensor

Claims (1)

[Claims] 1. A robot hand is provided with a pair of upper and lower load sensors so as to be capable of advancing and retreating with respect to each other so that the object to be measured can be clamped and released from the vertical direction by the pair of load sensors, and the pair of load sensors is operated by an arithmetic processing means. A weight measuring device that outputs a difference signal between the output signals of the load sensor.