JPS61284388A - Slip detector - 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 [Field of Industrial Application] The present invention relates to a device for detecting the surface of an object gripped by a robot hand such as an assembly robot. - [Prior art] This type of conventional surface detection device incorporates a small roller or a ball with a recess like a golf ball into the gripping surface of a robot hand, and detects the rotation of the roller or ball. By doing so, the entire surface of the object being grasped was detected.

[Problem that the invention seeks to solve]

Conventional slip detection devices require small rollers or balls to be precisely mounted so that they can rotate freely, and many small precision mechanical parts are used, resulting in problems with reliability and accuracy in detecting slip amount and slip direction. was dissatisfied with. Furthermore, there are other problems in that if the gripped object is small, it may not be possible to detect the entirety of the gripped object.

This invention was made to solve the above-mentioned problems, and it eliminates moving parts caused by rotation of rollers, etc., and improves reliability by eliminating temporal changes in the center of force action. It is an object of the present invention to provide a slippage detection device that can increase the detection ratio accuracy and detect the slippage of small objects. , for example, a support member for the target object such as a robot hand is placed parallel to the support member for the target object, and three or more force detection devices are installed between the support member and the receiving member to support the force received from the target object force. The force is distributed to each force detection device through a member, and the output of each force detection device is processed by a computer to detect the slippage of the target object.

[Effect]

In the surface detection device of the present invention, when the target object is supported by the support member, the acting force is distributed and transmitted to each force detection device supporting the support member. The temporal change in the center point of □ is calculated by a computer.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a case where the invention is mounted on a robot node.

FIG. 1 is a front view of this embodiment, and FIG. 2 is a side view thereof. In these figures, (1) is a receiving member that grips or supports a target object (see FIG. 4), and is shown as a robot node in this embodiment. (2) is a supporting member provided parallel to the finger portion of the robot hand (1), and is formed as a plate having a size corresponding to the finger portion. (3) is a force detection device interposed between the robot hand (1) and the flat plate (2); for example, four force detection elements made of conductive rubber are attached to the four corners of the flat plate (2); These force detection elements (31) are supported on the robot hand (11).

FIG. 3 is a block diagram showing the combination of this embodiment device and a microcomputer, in which (4) is an amplifier that increases the output of the force detection element (3) to an appropriate level;
is a multiplexer that switches the output of the amplifier (4), (6
) is an A/D converter that converts analog quantities into digital quantities;
(7) is a microcomputer as a device for processing information, that is, calculating the dimensions of a target object.

Next, the operation of this embodiment will be explained with further reference to FIGS. 4 and 5.

When an object contacts the plate (2) and exerts a force, that force is transmitted to each force sensing element (3). The force that the object is exerting on the plate (2) is determined by setting the center of action of the F1 force to the first position.
Illustrated in the diagram! In the −7 coordinate system, (xg , yg
), and the position and acting force of each force detection element (3) are (xi, yi) and fi (i=1 to 4), respectively.
), the following equation holds from the matching conditions regarding force and moment.

yg=Σ yifi/F (3
) i=1 That is, by performing the above equation using the output of the force detection element (3), the center position of the force exerted by the object on the plate +21 K can be determined. The above calculation is performed by a microcomputer (force), and for this purpose, the output of the force detection element (3) is increased by 1 [L,
Switch sequentially with the multiplexer (5), and switch the switch (6).
Through the microcomputer (7) K*! 5 included.

The amount of slip can be detected by looking at the temporal change in the center of action of the force exerted by the object on the plate f21. Fourth
The figure shows, for example, a case where a cylindrical object (81) is held by the robot hand (11), and FIG. FIG.

At a certain time tK, the moving object 8) is at the position shown by the solid line in FIG.
The center of action of the force A (xg(t), y
g(t) ) can be found from equations (1) to (3).

If the object (8) slides and moves to the position shown by the broken line after the time Δ has elapsed, then the center of action of the force at this time B
(xg(t+Δt), y, (t+=6t)) is also (
1) to (determined from formula 31).

Next, let ΔX and Δy be the amounts by which Δ has slipped in the time Kx-axis direction and y-axis direction, respectively, then Δt=x(t+Δt)−x(t) ・・・(4)g
g Δy=y (t+Δt)−y(t) ...(5
) g g . Calculations of equations (4) and (5) can be easily performed using a microcomputer.

The amount of slip in the xy plane can be constantly detected by determining the center of force action every minute time Δ by interrupting the timer and taking the difference from the previous position. A flowchart of the calculation at this time is shown in FIG.

In addition, in the above embodiment, the force detecting elements (3) are arranged at the four corners of the plate (2), but the force detecting device (3)
As for the arrangement, it is sufficient that at least one of them is in a straight line, so three or more are sufficient. Further, the present invention can be applied as a device for detecting slippage of a target object not only to a robot hand but also to detecting slippage of an object placed on a table.

〔Effect of the invention〕

As described above, according to the present invention, since the entire surface of the target object is detected as a temporal change in the position of the center of force action, reliability is improved and high precision can be obtained. It is effective to detect the slippage of small objects.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a side view of the same, FIG. 3 is a block diagram of the present invention, FIG. 4 is an explanatory diagram of a cylindrical object gripped by a robot hand, and FIG. FIG. 5 is an explanatory diagram showing the slippage of an object, and FIG. 6 is a flowchart of calculation. (1)...Receiving member, (2)...Supporting member, (3)...
...force detection device, (7)...calculation device. In each figure, the same reference numerals indicate the same or equivalent parts 0 Agent Patent attorney Tadashi Sato Rod part 1 Figure 2 Figure 6 Figure 6 Continued from page 1 Inventor Hiroyasu Taniguchi 8, Tsukaguchi Honmachi, Amagasaki City Inside the Chomeki Research Institute

Claims (1)

[Claims] A supporting member for the target object is provided in parallel with a receiving member that grips or supports the target object, three or more force detection devices are interposed between the receiving member and the supporting member, and based on the output of each force detection device, A detection device characterized by comprising a device that calculates a temporal change in a center point of a force of a target object acting on the support member.