JPH0794119B2 - Contact sensor signal processing circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a signal processing circuit of a contact sensor that processes signals from a contact sensor attached to various robots or other operating devices to detect contact information. .

[Conventional technology]

Generally, a robot or other operating device often performs a predetermined work while moving within a predetermined area. In such a case, abnormal contact with the installation object in the area may occur. As a means for efficiently avoiding such a situation and ensuring the safety of the apparatus, the most common means is to equip the periphery of the apparatus with a contact sensor such as a proximity sensor. In this case, in order to maximize its function, it is important to mount a large number of contact sensors at a large number of places and in various postures.

There are various types of contact sensors such as an ultrasonic type, an electrostatic type, and a light beam type, but it is difficult to say that all of them are small, lightweight, robust, and highly reliable. As a contact sensor that satisfies these conditions,
Whisker sensor with whiskers (Whisker-Senso
There is r).

FIG. 3 is a schematic diagram showing the basic configuration of the whisker sensor. In FIG. 3, 11 is a base, and 12 is the above-mentioned base 11.
Whiskers made of elastic metal wire or the like implanted in the whiskers, 13a and 13b are a pair of electrodes disposed opposite to the biding portion of the whiskers 2, and 14 is a seal member that covers the electrode portions, Reference numeral 15 is a voltage application terminal connected to the base end of the whisker 12, and 16a and 16b are output terminals connected to the electrodes 13a and 13b, respectively.

In the above whisker sensor, when the whisker 12 comes into contact with an obstacle and is deformed by receiving a pressing force as shown by an arrow, the whisker 12 and the electrode 13b come into contact with each other, and the voltage applied to the voltage application terminal 15 is applied to the output terminal 15b. Taken out. Thus, the contact with the obstacle can be detected electrically. The whisker sensor is connected to the central processing unit by a lead wire.

[Problems to be solved by the invention]

In the above configuration, in order to transmit the signal from each contact sensor to the central processing unit, it is necessary to connect each contact sensor and the central processing unit with a lead wire in a 1: 1 relationship. As a result, the lead dose becomes enormous, and the usefulness of using a large number of contact sensor groups is almost offset.

It is conceivable to provide a circuit by the ladder connection method as a means for solving such a problem. In the circuit by the ladder connection method, a contact sensor is provided in a ladder shape between a power supply line and a resistance line formed by connecting a large number of resistors in series,
It is configured to detect the sensor position in the ON state by detecting the voltage at both ends of the resistance line and taking the ratio thereof. If the circuit by the ladder connection method is used, the lead dose can be remarkably reduced, and since it can be constituted by only passive elements such as resistors, it becomes robust and inexpensive. However, when two or more contact sensors are turned on at the same time, there is a drawback that the sensor position cannot be accurately detected.

Therefore, the present invention requires only a small lead dose to connect between a large number of contact sensors mounted on a robot or the like and the central processing unit, and even when two or more contact sensors are turned on almost at the same time. However, it is an object of the present invention to provide a signal processing circuit of a contact sensor that can accurately detect the sensor position.

[Means for solving problems]

The present invention is characterized by taking the following means in order to solve the above problems and achieve the object.

(1) Between one power line and two resistance lines,
Differentiating the ON / OFF signal from the contact sensor to obtain a rising signal and a falling signal, connect a differentiating circuit in a ladder shape, and generate voltage signals corresponding to the rising signal and the falling signal on each resistance line. A first means is provided.

(2) A transmission system including a signal line, a ground line, and a power supply line for transmitting the voltage signal generated in each resistance line by the first means is provided.

(3) There is provided a second means for determining the mounting position of the contact sensor which has generated the ON / OFF signal by processing the signal transmitted by this transmission system.

In other words, the sensor signal is differentiated to obtain the pulse signals at the rising and falling edges of the sensor signal, the voltage signal corresponding to the pulse signal is extracted by the same circuit as the ladder connection method, and the voltage signal is calculated. The position of the operation sensor is determined by processing.

[Action]

By taking such measures, the transmission system needs only four signal lines, a power supply line, and an earth line, regardless of the number of contact sensors, and a plurality of contact sensors operate in parallel. Even in the case of performing, if either the operation start time point or the operation end time point is temporally shifted, the position of the operation sensor can be determined.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. As shown in FIG. 1, the present circuit includes a first block including a first means, a second block including a part of the second means, and a transmission line connecting the first block and the second block. And a central processing unit including another part of the second means. The first block is provided with one power supply line A and two resistance lines B1 and B2. Resistance line B
1 and the resistance line B2 are formed by connecting a plurality of resistors R in series, and both ends thereof are grounded to the ground E.
A plurality of diode circuits in which a pair of diodes are connected in series with opposite polarities are connected between the corresponding resistances of the resistance line B1 and the resistance line B2. A sensor signal detection circuit in which the whisker sensor 1 and a differentiation circuit including a capacitor 2 and a resistor 3 are connected in series is connected in a ladder shape between the power supply line A and the connection point between the diodes in the diode circuit. ing. Thus, the ON / OFF signal from the sensor 1 is differentiated by the differentiating circuit composed of the capacitor 2 and the resistor 3 to obtain a rising signal and a falling signal,
By supplying this to the voltage signal extraction circuit 4 including the resistance lines B1 and B2 and the diode circuit,
Voltage signals corresponding to the rising signal and the falling signal are generated at B1 and B2, respectively.

Four signal lines S1 to S4 are drawn out from the vicinity of both ends of the resistance lines B1 and B2 of the first block and enter the second block. Although not shown, the first block and the second block
Two lines, a power line and an earth line, are provided between the block and the block together with the signal line.

The second block is provided with an ON processing system and an OFF processing system circuit that separately processes the voltage signal transmitted through the signal lines S1 to S4 into a rising signal and a falling signal. . That is, the non-inverting amplifiers 5a and 5b and the divider 6 are ON processing circuits that carry out arithmetic processing of the rising signal, and the signal lines S1 and S2 are connected to this circuit. Further, the voltage followers 7a and 7b, the inverting amplifiers 8a and 8b, and the divider 9 are OFF processing circuits for processing falling signals, and the signal lines S3 and S4 are connected to this circuit. .

The dividers 6 and 9 of the second block are connected to the central processing unit 12 via the A / D converters 10 and 11, respectively.
It is connected to the.

Next, the operation of the circuit thus configured will be described with reference to the timing chart shown in FIG. When the sensor 1 is turned on at time t1 as shown in FIG. 2, the voltage instantaneously rises from the ground level to the power supply level. Then,
The rising portion is differentiated by the differentiating circuit composed of the capacitor 2 and the resistor 3, and a pulse signal is generated as shown in FIG. 2, which is added to the diode circuit. Since the pulse signal is a positive signal, it passes through the forward diode D _i and is divided by the resistance line B1. Thus, a signal such as ′ in FIG. 2 is extracted, and this is the signal line S
Input to the non-inverting amplifiers 5a and 5b via 1 and S2. Note that the above signal 'does not affect other sensor signals because all the other diodes D1 _{1 to} D _n connected to the resistance line B1 have the opposite relationship.

Similar phenomenon occurs when sensor 1 is turned off, but at time t
Since the pulse signal differentiated by 2 is a negative signal, it passes through the diode D _i ′ in the opposite direction and is divided by the resistance line B 2. Thus, a signal such as' in FIG. 2 is taken out, and this is input to the voltage followers 7a, 7b via the signal lines S3, S4. Above, 'even if the signal of the other diode D ₁ connected to the resistive line B2' so to D _n 'are all substantially opposite relationship does not affect the other sensor signals.

, 'Are amplified by the non-inverting amplifiers 5a, 5b,
Division is performed by the divider 6. The result of the division depends on the voltage division ratio of the resistance line B1, and therefore has a value specific to each sensor position.

, ', Are also input to the inverting amplifiers 8a, 8b via the voltage followers 7a, 7b, amplified here, and then divided by the divider 9. Since the result of the division depends on the voltage division ratio of the resistance line B2, it has a value unique to each sensor position as described above.

Since the voltage division ratios by the resistance lines B1 and B2 are equal,
The analog value shown in Fig. 2 output from the divider 6 of the ON processing system and the analog value shown in Fig. 2 output from the divider 9 of the OFF processing system when a certain sensor is turned ON. Will be at the same level. The above analog values are converted to the A / D converter 10
And 11 are converted into digital signals and input to the central processing unit 12. Thus this central processing unit 12
Is used to determine which sensor the signal is from. In this case, the ON / OFF states of all the sensors are accurately detected in real time by performing a comparative determination on the signal generation timing.

The present invention is not limited to the above-mentioned embodiment,
Needless to say, various modifications can be made without departing from the scope of the present invention.

〔The invention's effect〕

According to the present invention, the differential operation of the sensor signal is performed to obtain the pulse signal at the rising and falling edges of the sensor signal, and the voltage signal corresponding to the pulse signal is taken out by the same circuit as the ladder connection method, Since it is configured to determine the position of the operation sensor by processing the voltage signal, the lead dose that connects between many contact sensors mounted on the robot etc. and the central processing unit is very small. Moreover, each sensor position can be accurately detected even if two or more contact sensors are turned on almost simultaneously, and each sensor position is detected even when two or more contact sensors are turned off almost simultaneously. It is possible to provide a signal processing circuit of a contact sensor that can be accurately detected.

[Brief description of drawings]

1 and 2 are diagrams showing an embodiment of the present invention, FIG. 1 is a circuit diagram showing the entire configuration, and FIG. 2 is a diagram showing operation timings of the circuit of FIG. FIG. 3 is a cross-sectional view of a whisker sensor shown for explaining the problems of the conventional technique. 1 ... Whisker sensor, 2 ... Capacitor, 3 ... Resistor, 5a, 5b ... Non-inverting amplifier, 6,9 ... Divider, 7a, 7b ...
… Voltage followers, 8a, 8b …… Inverting amplifiers, 11,12…
… A / D converter, 12… Central processing unit, A… Power line, B1, B2… Resistance line, S1 to S4… Signal line.

Claims (1)

[Claims] 1. A ladder-like differential circuit is provided between one power supply line and two resistance lines to obtain a rising signal and a falling signal by differentiating an ON / OFF signal from a contact sensor. ,
First means for generating a voltage signal corresponding to the rising signal and the falling signal on each resistance line, and a signal line for transmitting the voltage signal generated on each resistance line by the first means, a ground A transmission system including a line and a power supply line; and second means for determining a mounting position of the contact sensor that has generated the ON / OFF signal by processing the signal transmitted by the transmission system. A signal processing circuit of a contact sensor characterized by the above.