JPS60218045A - Grip sensor - Google Patents

Abstract

PURPOSE:To easily detect the contacting position and pressing load of a robot hand by composing a pressure sensing unit of pressure conductive rubber, electrodes stacked on both sides of the pressure conductive rubber, and resistances connected electrically to the pressure conductive rubber in parallel, and arranging pressure sensitive units in plural arrays and in many stages. CONSTITUTION:The couple of electrodes 6a are connected across the pressure conductive rubber 5, and the resistances 9 are connected to the pressure conductive rubber 5 electrically in parallel and also connected in series in each array. Further, conductive rubber 5 in each stage differs in operating load (f) so that f1<f2<f3<f4. The grip sensor 4 constituted as mentioned above is stuck on the hand 3 of a robot to grip a work 1. In this case, the resistance value of the circuit goes to 4r when the pressure load on the work 1 is smaller than f1 and about 3r when the pressure load is >=f1 and <=f2, so that the resistance value of the circuit varies stepwise with the pressure load (f).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a grasping device attached to a robot hand.

[Technical background of the invention and its problems]

FIG. 7 shows a robot for gripping a work l. This robot consists of an arm 2 and a gripping part 3 attached to the tip of the arm 2. Of these, the /S hand 3 is composed of gripping members 3a and 3b that can slide toward or away from each other. In this robot, by operating the arm 2, the node 3 attached to the tip of the arm 2 is activated.
is moved to the position of the workpiece L, and then the gripping member Ja is moved to the position of the workpiece L.

The workpiece 1 is gripped by the opposing surface 3'b.

By the way, when a robot grips a work l,
It is important to detect whether the work l is held in a predetermined position or with a predetermined pressing load.

This is to prevent the work l from falling and being damaged.

Therefore, in order to prevent the work l from falling or being damaged,
Conventionally, the hand 3 was equipped with a strain gauge or a grip sensor such as a load cell.However, although the strain gauge is small and lightweight, the reproducibility of the pressing load is poor, so it is difficult to accurately detect the pressing load. Can not. t
Furthermore, in order to detect the contact position of the work l, a large number of strain gauges and signal converters are required, which is expensive. Furthermore, since strain gauges handle minute currents, cable wiring becomes complicated.

On the other hand, although the load cell has excellent reproducibility of the pressing load, it is difficult to attach to the robot's hand 3 because of its large size and weight. Also.

When detecting the contact position of the work l, a large number of load cells are required, which is expensive.

Therefore, grip sensors using pressurized conductive rubber have recently been devised as an alternative to strain gauges and load cells. The pressurized conductive rubber used in this grip sensor is made of rubber with pressurized conductivity that shows a rapid resistance change from an insulating state (toMΩ or more) to a conductive state (several tens of Ω or less) in response to pressure stimulation. , is composed of a composite material that combines silicone and metal particles in a unique way.

A gripping sensor l is made by laminating electrode sheets on the inside and outside of this pressurized conductive rubber, and this gripping sensor l functions as a pressure switch.

The grasp sensor I configured in this manner has the advantage that it is inexpensive, lightweight, and has a thin inner thickness, so that it can be easily attached to the surface of the robot's hand 30.

However, in the conventional gripping sensor sensor that uses electrostatic rubber only as a 7-step pressure switch, the pressing load can be turned ON or OFF.
F? It was only possible to detect the level, and it was not possible to detect even the finer values of the pressing load.

[Purpose of the invention]

The present invention has been made in view of these difficulties, and it is an object of the present invention to provide a grip sensor that can be easily attached to a robot hand and that can easily detect contact positions and pressing loads.

[Summary of the invention]

The present invention provides a gripping sensor that is attached to a hand of a robot and detects the pressing load of a workpiece gripped by the hand, which includes a pressurized conductive rubber, electrodes superimposed on both sides of the pressurized conductive tab, and the pressurized conductive rubber. Pressure-sensitive units consisting of resistors electrically connected in parallel to conductive rubber are arranged in multiple rows and stages, and the pressure-sensitive units belonging to each row are electrically connected in series, and The pressurized conductive rubber has different pressure sensations.

[Embodiments of the invention]

The present invention will be explained below based on an embodiment shown in the drawings. Note that the same parts as in the conventional one are given the same reference numerals, and the explanation thereof will be omitted.

FIG. 1 shows an embodiment of a grip sensor sensor according to the present invention attached to a robot hand 3. As shown in FIG. This grip sensor
The structure consists of a conductive sheet (j) made of pressurized conductive rubber and electrode sheets (t) stacked above and below the conductive sheet (j), which are arranged in multiple stages via a printed circuit board, and the whole is covered with an insulating sheet. It is coated with r. And in this grip sensor tag, each stage of conductive sheet! The feeling of pressure is different. In addition, the electrode sheet 6 is composed of a large number of electrodes 4a formed in a shear array shape by etching capes. Furthermore, in this grip sensor tag, as shown in Fig. 2, pressurized conductive rubber! A pair of electrodes Ah facing each other are connected to each other, and a resistor is electrically connected in parallel to the pressurized conductive rubber jK. Additionally, the resistors are electrically connected in series in each column.゛That is, this grip sensor≠ is a pressurized conductive rubber j.

This pressurized conductive rubber! l pairs of electrodes 6a superimposed above and below
, and a resistor electrically connected in parallel to the pressurized conductive rubber j are arranged in multiple rows and stages, with a pressure sensitive unit l belonging to each row.

can be thought of as electrically connected in series, and the pressure sensation of the pressurized conductive rubber j at each stage is made different. Figure 3 shows the equivalent circuit of this grip sensor t.
Pressurized conductive rubber! is represented by the switch symbol e.

Next, the action of this gripping sensor will be explained.

Now, the operating load of the pressurizing conductive beam j (represented by sleat and el *84, respectively) in each stage in the row indicated by the broken line in FIG. 3 is expressed as flat sin sf4 (
ft < tm < tm < f4), and the resistance value of each resistor is r.

In this case, if the pressing load of the work l is smaller than fl, the pressurized conductive ♂m! is not operated. In other words, pressurized conductive ♂mu!
is in an insulating state, so when electricity is applied, the current is resistance? It is expressed by flowing along the side. Therefore, the resistance value of the circuit in this case is 44r.

Further, if the pressing load of the work l is f, 7 or more, f, or less, only the pressurized conductive female mj with the operating load f is operated. Then, when the internal resistance value of the pressure conductive beam j becomes lower than r, when electricity is applied, the pressure conductive beam j in the pressure sensitive unit IO! Current will flow through the side. On the other hand, in other pressure-sensitive units IO, pressurized conductive ♂! Since it is not operated and is kept in an insulated state, current will flow on the resistive side. Therefore, the resistance value of the circuit in this case is approximately 3r.

The resistance value change obtained in this manner is shown in Figure 2, and it can be seen that the resistance value r of the circuit changes stepwise as the pressing load f changes.

Thus, by detecting the resistance value r of this circuit, the pressing load f will be detected conversely.

Figure 3 shows a state in which a cylindrical workpiece l is gripped by the hand 3 having this gripping sensor. The resistance value r of each column at sensor≠ changes. Thus, by detecting the relative displacement in each row of resistance values r, the gripping state of the work l can be easily known.

As described above, the gripping sensor Hiro according to the embodiment is small and lightweight, so it can be easily attached to the hand 3.

Moreover, it has the advantage that the contact position and pressing load can be easily detected.

〔Effect of the invention〕

As explained above, the present invention can be applied to a robot hand.
In a gripping sensor that detects the pressing load of a workpiece attached to a hand, a pressurizing conductive beam, nine electrodes superimposed on both sides of the pressurizing conductive beam, and an electric current to the pressurizing conductive beam are used. Pressure-sensitive units consisting of resistors connected in parallel are arranged in multiple rows and stages, and the pressure-sensitive units belonging to each row are electrically connected in series, and the pressure sensation of the pressurized conductive member in each stage is Since each type is different, it is small and lightweight, making it easy to attach to the hand.

Moreover, it has the advantage that contact placement and pressing load detection can be easily performed.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of an embodiment of the grip sensor according to the present invention, FIG. 2 is a perspective view showing a part of the grip sensor shown in FIG. 1, and FIG. 3 is a perspective view of the grip sensor shown in FIG. 1. The equivalent circuit diagram of the sensor, Figure 1 is a diagram showing the operating state of the gripping sensor shown in Figure 1, Figure 3 is a perspective view of the robot gripping the workpiece, and Figure 6 is a diagram showing the operation state of the gripping sensor shown in Figure 3. A graph showing the change in resistance value when gripped, FIG. 7 is a perspective view of the robot. 3...Hand, l...Grip sensor! ... Pressure conductive ♂me, 6a... Electrode, 2... Resistor, 10... Pressure sensitive unit. 3rd figure 84th S Ii a * (kg/am 5th figure #!+6th

Claims (1)

[Claims] (1) A gripping sensor that is attached to a robot hand and detects the pressing load of a workpiece gripped by the hand includes a pressurized conductive rubber, electrodes superimposed on both sides of the pressurized conductive rubber, and the pressurized conductive rubber. Pressure conduction 1! Pressure-sensitive units consisting of resistors electrically connected in parallel to the chem are arranged in multiple rows and stages, and the pressure-sensitive units belonging to each row are electrically connected in series, and furthermore, the pressure-sensitive units in each stage are connected in series. The pressure sensation of each rubber is different! Grip sensor with gi. (,2) The grip sensor according to claim 1, wherein the pressure sensing units are arranged in multiple stages.