JPH01121730A - Sensor circuit of tactile sensor - Google Patents

Abstract

PURPOSE:To make a device simple and compact and to drive it by a small- capacity power source by providing the tactile sensor made of pressure-sensitive conductive rubber and the sensor circuit which is arranged on the same board with output switches for respective electrodes. CONSTITUTION:A couple of electrodes are arranged at each pressing force detection point across the pressure conductive rubber which varies in resistance value with pressing force, electrodes for one polarity of each voltage Eij are divided into a power source side where the electrodes are arranged as many as power source switch circuits Sj in parallel to one another, and one of the circuits Sj and electrodes in each group are connected mutually by conductors. Further, electrodes for the other polarity are divided into an output group where they are arranged as many as output switch circuits Si in parallel at right angles to the dividing direction of the power source side group, and a circuit Si and an electrode Eij in each group are connected mutually by a conductor. The sensor circuit 1 where the tactile sensor made of the pressure- sensitive conductive rubber and circuits Sj for the respective electrodes Eij are arranged on the same board is provided and driven effectively by the small- capacity power source.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a tactile sense suitable for a robot hand that recognizes the shape of an object by tactile sensation, and that grips fragile objects or heavy objects while adjusting the gripping force. This relates to the sensor circuit of the system.

[Prior art]

In order to recognize the shape of an object by the sense of touch, the shape of the object, for example, a portion corresponding to the outline, can be recognized by the sense of touch and the shape can be determined. A tactile sensor used in such cases has been developed that detects the pressure applied to a measurement point when the sensor is pressed against an object. When such sensors are applied to robots that grip objects through surface contact, such as the way they grip objects with their hands, they can be used to grip objects by adjusting the force applied to each part. It is being said.

Therefore, the greater the number of pressure measurement points, the higher the detection accuracy such as shape recognition.
A haptic system is being developed that has as many as 4096 measurement points (64 arranged vertically and horizontally) on a 2QIl measurement surface. A circuit as shown in FIG. 3 has been proposed as the pressing force detection circuit of this distributed type tactile sensor.

In the figure, this distributed antenna sensor 1 has a pair of electrodes Eij (i=
0~8m~8m+7~63, j=0~n-1, n, , n
1,001 to 63: Total number = 4,096)
, a resistor, and a diode S ij (i
-0~8m~8m+7~63, j=0~n-1, n, n
+l~63: total number = 4096 pieces) are connected by conducting wire 2.

As shown in FIG. 3, the electrode Eij is formed by combining a comb-shaped electrode Ep and an electrode Eo in an interlocking manner, and has a rectangular shape with a negative side of approximately 5 + u. Note that the electrode Ep is the electrode connected to the power supply side, and the electrode Eo is the electrode connected to the power supply side.
respectively mean the electrodes connected to the output side. A pressure-sensitive conductive rubber 3 is placed on this electrode EijO (load side). In the figure, the pressure-sensitive conductive rubber 3 is shown to have the same size as the electrodes, but usually the individual electrodes Eij are attached to a sheet-like material.

As mentioned above, tactile sensor 1 is approximately 32 cI! It is necessary to install 4,000 gold switches on a sensor board that is the size of one square, and the conductor wire 4 that supplies power to each type of WsEp is connected to it, so the work efficiency of wiring these is extremely low. There is.

Therefore, in the conventional example shown in FIG. 3, in order to miniaturize the switch, incorporate it into the tactile sensor 1, facilitate wiring work, and make the device compact, an FET is used as the switch element.
The switch circuit using 1 x 8 cells, the bin pitch is 1
．． A hybrid IC 3 having a diameter of 26 mm is assembled into one switch board and placed behind the tactile sensor 1.

However, in the case of the sensor circuit shown in FIG. 3, this conventional method requires wiring 4096 conductive wires 2 at approximately 511 intervals to connect the sensor board on which the individual electrodes Eij are arranged and the switch board on which the switches Sij are arranged. Since it is necessary to connect the power supply conductor 4 (FIG. 4) thereon, there is a problem in that the work efficiency of wiring work and device assembly is extremely low.

Moreover, as mentioned above, since a large number of conducting wires 2 are arranged behind the tactile sensor 1, there is no means to hold the tactile sensor 1 from the back (in order to increase the strength, the sensor board itself must be made sturdy). However, there is a problem in that it is difficult to make it thin and lightweight.

[Purpose of the invention]

The present invention has been made to solve the above problems, and provides a sensor circuit having a sensor circuit in which a tactile sensor made of pressure-sensitive conductive rubber and an output switch for each electrode can be arranged on the same board. By doing so, the present invention aims to provide a sensor circuit for an antenna system that can simplify and downsize the device and can be driven by a power source with a smaller capacity.

[Structure of the invention]

The configuration of the sensor circuit of the tactile system of the present invention to achieve the above object is as follows: a distributed tactile sensor, a power switch consisting of a switch element connected in parallel to one power source, and a power switch consisting of a switch element connected in parallel to one output terminal. The distributed tactile sensor has a pair of electrodes arranged at each of a plurality of pressing force detection points via a pressure-sensitive conductive rubber whose resistance value changes depending on the pressing force. , and the electrodes of one polarity of each electrode are divided into power supply side groups having the same number as the plurality of power switches and arranged in parallel with each other, and connecting with any one of the power switch circuits in each group. and the electrodes of the other polarity of the electrodes are connected by a conductor, and the electrodes of the other polarity are connected in the same number as the plurality of output switches, in parallel with each other, and in a direction crossing the dividing direction of the power supply side group. The device is characterized in that it is divided into arrayed output side groups, and the output switch and the electrodes in each group are connected by conductors.

The pressure-sensitive conductive rubber is a material in which conductive particles such as carbon are dispersed and contained in an elastic body such as silicone rubber, and is usually used in the form of a sheet with electrodes arranged at each detection point on the sheet. It is a rubber-like material that exhibits a resistance value as an insulator in a normal state, and whose resistance value decreases in response to the force that presses the rubber elastic body. The pressure-sensitive conductive rubber is usually used in the form of a sheet, but it can also be coated with a paint to form a film on the electrode. However, when carrying out the present invention, the pressure-sensitive conductive rubber sheet may not be used, and the pressure-sensitive conductive rubber sheet may be provided for each electrode.

That is, the electrodes for detecting pressing force are divided into a power supply side group and an output side group whose directions intersect with each other, the electrodes in the groups are connected by a conductive wire, and a power switch and an output switch are connected to the conductor wire. The arrangement provided serves to reduce the number of switches from the same number of conventional electrodes to the number of groups. Specifically, in the case of electrodes arranged in a 64x64 grid pattern as shown in Figure 3, the number of output switches that conventionally required 4096 can be reduced to 64.
It can be reduced to .

An FET with high input impedance, low noise, low distortion, and favorable temperature stability is suitable for the output switch, but an open collector type TTL is suitable for miniaturizing the device.
Preferably, a decoder consisting of an IC or MOS-IC is used. For example, when using an FET for the output switch, the opening/closing of the gate part is an open collector type T.
In order to perform this with the high signal of TL, a circuit that pulls up the gate impedance using a resistor R0 may be used to lower the gate impedance, as in the switch circuit shown in FIG. Using an IC decoder, the output terminal of the signal that drives the FET gate is connected to the FET gate via a coupling capacitor, and at the same time an operating voltage is applied using a voltage divider circuit made of resistors. A circuit can also be used. The latter circuit allows the operating current of the entire sensor circuit to be reduced to a small capacity.

As a preferable power switch, a switching circuit having the performance of a digital transistor or the like can be used.

In addition to the horizontal electrode as shown in FIG. 3, electrodes that can be used in the present invention may be electrodes arranged so as to sandwich pressure-sensitive conductive rubber from both sides.

〔Example〕

FIG. 1 shows a sensor circuit of a antenna system according to an embodiment in which an OMO3-IC is used as an output switch. The sensor part of the antenna system of this example includes
In order to recognize the shape of an object placed on a 2cm x 32cm tactile sensor, 64 sensors were installed vertically and horizontally (4096ft in total).
The detection points of M) are arranged in a matrix pattern, and each detection point has an electrode Ei.
I used the one where j was placed. In addition, Figure 2 shows the cross section of the pressure-sensitive conductive rubber 3 along the second power supply conductor j N = 1) and the power supply and output circuit connected to the electrode Eij (i = 2゜j = 1) placed here. This is what is shown. It should be noted that the same numbers are attached to the members that are functionally similar to those in FIG. 3 to facilitate correspondence. The electrodes in FIG. 2 are shown with electrodes of each polarity sandwiched between pressure-sensitive conductive rubber to facilitate understanding of the circuit configuration.

The multiplexer 3 that drives the 64 output switches Si consisting of FETs used in this example has a model number of 74HC.
0MO5-IC with 238 high signal outputs (for surface mounting:
The multiplexer 4 that drives the power switch Sj uses 0MO3-IC, N which has a low signal output and has a model number of 74HC13B.
, ~No. Each of these elements is a 3-to-8 decoder that decodes one of eight output lines depending on the conditions of three select inputs and three enable inputs.

Therefore, each 64 switches si.

To open and close sj, it is necessary to use 8 pieces of 74HC138 and 238, respectively. Therefore, 8 I
multiplexer 3 as a decoder for controlling C.
4, the above 74HC138M9 and Mlo were used. Note that a normal digital transistor (DTB) is used as the power switch sj in this figure.

Now, the circuit Ci that drives the output switch Si consisting of the FET of the sensor 1 connects the 64 i-th output pin of the multiplexer 3 and the gate of the FET of the switch Si with a coupling capacitor C, as shown in the figure. A bias voltage of 13 volts was applied by a voltage divider circuit consisting of resistors R2 and R3. Note that D in the figure is a diode for cutting the sneak current.

The voltage for operating the switch Si only needs to have a current capacity sufficient to create the switching level of the FET. Therefore F
The voltage applied to the gate of the ET (-3 volts) was obtained from the 5 volt power supply that activated the tactile sensor. That is, the RC oscillation circuit is oscillated by 5V supplied from the 24th and 25th bins of the output terminal 5 of the control device (not shown), and the negative voltage of the obtained AC voltage is converted into a 13-volt circuit configured with a transistor and a constant voltage diode. The voltage is supplied from a constant voltage circuit 10 that obtains volts.

One of the features of the sensor circuit of this embodiment is that the FE
The advantage is that everything, including the bias voltage of -3V for the gate of T, can be provided by a single power supply.

Next, the operation of this embodiment will be explained. The power supply multiplexer 4 of each electrode Eij has a first output terminal 5 of the control device 5.
The scanning address signal of the power switch Sj is supplied from pins 1 to 16 and the 19th pin (for enable input), and the output multiplexer 3 is supplied with the address signal for scanning from pins 1 to 6 and pin 9 (for enable input). The scanning address signals of the output switches Si are applied to the respective signals, which are processed into operating signals by the receiver circuits 11 and 12, and then sent to the A- of the decoders M1 to M6 and N1 to N8.
C pin and each of the decoders M1 to M e , N 1
~N6, respectively, are sent to decoders M9 and M
u,) to the A-C pins.

Decoders M9, M, and o each have decoders M1 to Me.
, N1 to N6 are sequentially applied to the corresponding decoders, and the decoders M1.,N6 are activated by this signal. −.

or Ma, N7. By outputting a high signal to open the switches Sj and Si, which are activated sequentially from - or N6, a voltage is sequentially applied to each electrode Eij, and at that time, a current corresponding to the pressing force is taken out from the output terminal 7. It will be done.

The output switch Si of the present invention can be implemented, for example, by a switch circuit shown in FIG. 3, in addition to the drive circuit Ci shown in FIG.

The characteristics of the switch circuit shown in FIG. 1 will be explained below in comparison with the conventional switch circuit.

In other words, when using an FET as an output switching element, in Figure 3, the opening and closing of the gate section is done by the H of the TTL open collector, so it is necessary to lower the impedance of the gate, so it is pulled up with a resistor R1 (for example, 1Ω). There is a need to.

In this case, the time to output the high signal to open the gate is 1/64 of the total time (because there are 64 electrode lines i), and the output during the subsequent 63/64 time is L, so 1 For example, a current of about 10 mA flows through the resistance of Ω. This is the same for the other 63 wires, so the total amount of heat is 640 mA, which is a considerable amount of heat.

On the other hand, the output switch circuit Si shown in Fig. 1 can reduce the operating current to the μ ampere order, so the overall current capacity can be significantly reduced, the power supply capacity can be reduced, and the heat generation amount can be reduced. Since the sensor circuit is also made smaller, it is possible to downsize the sensor circuit.

Furthermore, when the sensor circuit shown in Figure 1 is used, the current that opens and closes the FET requires an extremely small capacity as described above, so the bias voltage (-3V) applied to the gate of the FET is equal to the 5V used in the sensor circuit. It can be made from the power supply voltage. Therefore, the conventionally used output switch circuit (for example, Fig. 3), which required two power supplies of +5 volts and 15 volts, can be used with a single power supply, simplifying the circuit and making it a compact device. It also has the feature of being able to

To summarize the advantages of the sensor circuit of the embodiment described above,
The number of output switches that conventionally required 4096 has been reduced to 64, and the sensor circuit can be driven with a single +5 volt power supply, thus reducing the number of parts used, simplifying the circuit, and increasing the output in inches. The current value flowing through the drive circuit was reduced, and by assembling the tactile sensor and sensor circuit onto a single sensor board, it was possible to make it smaller, lighter, and stronger.

〔Effect of the invention〕

As explained above, the sensor circuit of the tactile image system of the present invention includes a distributed tactile sensor, a power switch circuit consisting of a switch element connected in parallel to one power source, and a plurality of sensor circuits connected in parallel to one output terminal. Consisting of an output switch circuit, the distributed antenna sensor has a pair of electrodes arranged at each of a plurality of pressing force detection points via a pressure-sensitive conductive rubber whose resistance value changes according to the pressing force. The electrodes of one polarity are divided into power supply side groups having the same number as the plurality of power switch circuits and arranged in parallel with each other, and connecting any one of the power switch circuits to the electrodes in each group. connected by a conductor, and the electrodes of the other polarity are arranged in the same number as the plurality of output switch circuits, in parallel with each other, and in a direction intersecting the dividing direction of the power supply side group. Since the output switch circuit is divided into output groups and the output switch circuit and the electrodes in each group are connected by conductors, the following effects can be obtained.

(1) For example, if the number of pressing force detection electrodes arranged in a tactile sensor is increased by four times, the number of output switch circuits and the number of accompanying parts used in the sensor circuit of the present invention can be doubled.

(2) This is extremely advantageous when thousands of electrodes are used, such as in a tactile imaging system, but since the number of switch circuits is small, it is possible to incorporate the tactile sensor and its drive circuit into a single sensor board. Therefore, the tactile sensor and its sensor circuit can be made smaller and lighter.

(3) As mentioned above, by using only one sensor board, the board can be reinforced easily, resulting in a sturdy structure, which can be used for applications such as heavy objects, shape recognition that requires strong pressure, and robot hands. Can be expanded.

[Brief explanation of the drawing]

FIG. 1 is a sensor circuit diagram of an antenna system according to an embodiment;
Figure 2 is a cross-sectional view of the pressure-sensitive conductive rubber shown in Figure 1, Figure 3 is a sensor circuit diagram of a conventional tactile system, and Figure 4 is a perspective view of the horizontal electrode used in Figure 3. be. ■...Sensor section, 3...Output side multiplexer, 4
...Power multiplexer, 8...Pressure-sensitive conductive rubber, 9
... Power supply side polarity electrode, 10... Output side polarity electrode, E i j- electrode, M+ = Ma, N+ ~ Ne
Dacoder consisting of o-CMO3-IC, Si...output switch, Sj...power switch. Agent Patent Attorney Nobuo Ogawa −

Claims (1)

[Claims] The distributed antenna sensor consists of a power switch consisting of a switch element connected in parallel to one power source, and a plurality of output switches connected in parallel to one output terminal. A pair of electrodes are arranged at each pressing force detection point via pressure-sensitive conductive rubber whose resistance value changes according to the pressing force, and each electrode has the same number of electrodes of one polarity as the plurality of power switches. Furthermore, the circuit is divided into power supply side groups arranged in parallel with each other, and any one of the power switch circuits and the electrodes in each group are connected by a conductor, and the electrode of the other polarity of the electrodes is connected to the power switch circuit. , divided into output side groups having the same number as the plurality of output switches, arranged in parallel with each other and in a direction crossing the division direction of the power supply side group, and furthermore, the output switches and the output switches in each group are A sensor circuit for a tactile system characterized by connecting an electrode with a conductor.