JPS60207081A - Proximity sensing apparatus - Google Patents

Abstract

PURPOSE:To detect a proximity distance without being affected by circumferential light, by allowing a light emitting element to emit light by an AC current with frequency (f) and taking out only a component with frequency (f) in luminous flux incident to a light receiving element. CONSTITUTION:A reflective type photosensor 1 is constituted by integrating a light emitting diode 2 and a phototransistor 3 on a single surface, and can emit and receive light in the same direction and can transmit and receive a signal through a lead wire 4. The reflective type photosensor 1 is used in a state arranged to the leading end of the finger 6 of a robot hand 5. An AC power source circuit 9 allows the light emitting diode 2 to emit light with frequency (f). Emitted luminous flux is reflected by a front object and converted to an electric signal upon the incidence to the phototransistor 3. The component with frequency (f) of the electric signal is amplified by a selection and amplification circuit 10 and noise is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a proximity sensor device suitable for use in a robot hand.

[Background technology of the invention and its problems]

When a robot hand grasps an object, it needs to confirm that the object to be grasped exists between the fingers, and that the object to be grasped is at the center of the opposing fingers by detecting the distance sound between the fingers and the object being grasped. There is.

If you grip without an object in the center of the fingers,
If the object being held is knocked over or bent, the fingers may be completely damaged. Therefore, in order to fully know that there is an object to be grasped between the opposing fingers, and at the same time fully control the position of the robot's arm so that the object to be grasped is in the center of the opposing fingers, the distance between the fingers and the object to be grasped must be completely controlled. A proximity sensor device is required for measurement.

Conventionally, as a sensor device for this kind of use, when detecting the presence of a grasped object, a light emitting diode and a phototransistor are all embedded in the left and right fingers, and the fins are one inch apart. The presence of the object being held is detected by the presence or absence of light passing through it.

Furthermore, the distance between the grasped object and the finger was determined by calculating the entire distance using the principle of triangulation. In the 911-e, several light emitting diodes arranged in a straight line sequentially emit light, the total intensity of the light reflected from the held object is detected by a phototransistor, and the distance to the held object is estimated by estimating the optical path from the magnitude of the output. This is a sensor that utilizes the phase shift of light due to the difference in what is being sought and the length of the light path. However, such a sensor has the drawback that its measurement accuracy is affected by light from other illumination surrounding the robot hand.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a proximity sensor device capable of detecting a close distance without being influenced by surrounding light; Compact and lightweight, can be placed anywhere on the robot
The object of the present invention is to realize a proximity sensor device suitable for a robot, which can be attached to the robot and has sufficient performance to avoid collision of the robot with the environment.

[Summary of the invention]

Light emitting element and light receiving element? For example, the combined reflective photosensor is attached to a desired location on the robot, and the total frequency f of the light emitting element is
It emits light with an alternating current of This is a proximity sensor device configured to detect.

〔Effect of the invention〕

The present invention makes it possible to detect close distances without being affected by surrounding light, and also allows the robot to be easily attached to any location, which was not possible with conventional large-scale sensors. It becomes possible to fully automatically avoid collisions with the environment. Therefore, it will be easy to realize intelligent robots with excellent autonomy in terms of collision avoidance, and the effects will be significant.

[Embodiments of the invention]

Embodiment 11 of the present invention will be described in detail below. FIG. 1 is a diagram showing a reflective photosensor 1 used in the proximity sensor device of the present invention, in which a light emitting diode 2 and a phototransistor 3 are integrally formed on a single surface, can emit and receive light in the same direction, and have a lead wire. 4 can send and receive signals.

The reflective photosensor 1 is used by being placed at the tip of the finger 6 of the robot hand 5, as shown in FIG. When the robot hand 5 lowers the fingers 6 to grasp the object 7, if the position data of the platform 8 is not accurately given to the robot, the rigidity of the robot will be greatly increased, even if the error is ~00 microns. If it were made, a very large amount of force would be applied to the robot, right? There is a risk of damaging or destroying the stand.

Therefore, when the distance between the tip of the finger 6 and the stand 8 reaches a value, the full signal is output and the robot is controlled.
Collision between the finger 6 and the stand 8 can be completely avoided.

In the signal processing circuit of the proximity sensor device of the present invention, as shown in FIG. 3, the light emitting diode 2 is connected to an AC power supply circuit 9 of frequency f, and Circuit 10, rectifier circuit 11, comparison circuit 1
2.13 are connected and configured.

The AC power supply circuit 9 causes the light emitting diode 2 to emit light at all frequencies f. The emitted light beam is reflected by an object in front and enters the phototransistor 3, where it is converted into an electric signal. The frequency f component of the electrical signal is amplified by the selective amplification circuit 10 and noise is removed. This signal is rectified by full rectifier circuit 1,
An electrical signal proportional to the intensity of the incident light beam is obtained.

This signal is input to the comparison circuits 12 and 13, and when it becomes larger than the set voltage of each comparison circuit, the comparison circuit outputs 14.
．． Make 15 become "1" and use this signal as a mouth? )1
- The robot is configured to avoid collisions by controlling the robot. By the way, are comparison circuits 12 and 13 robots? When moving at high speed, the robot speed is changed to low speed when the distance from the obstacle in front is t2, and tlO
This is provided in order to control the robot to stop smoothly by setting each set voltage so that the robot stops at a certain point (t2>tt).

Of course, if the robot is moving at low speed, one comparison circuit may be used to control the robot to stop suddenly. Also input the output of rectifier circuit 1 into a computer and compare the signals. You can also do it in a computer.

[Other embodiments of the invention]

Next, another embodiment 1 of the present invention will be explained.

If the robot hand moves at high speed, if you issue a command to stop it early or switch to a low speed, there is a risk that the robot hand will collide with an obstacle due to control delays. In such a case, as shown in Fig. 4, the output signal of the rectifier circuit 1 is differentiated once by the differentiating circuit 16, and then processed by the comparator circuit, and when this differentiated signal reaches a certain value, the robot By decelerating or stopping the robot completely, when the robot hand is fast, the robot can be fully decelerated or stopped over a relatively long distance, and when the robot hand is slow, the robot can be fully decelerated or stopped over a relatively short distance, which saves time. This enables efficient III sudden avoidance control.

As another embodiment of the present invention, as shown in FIG.
The comparison circuit 13 shown in FIG.
By substituting with This allows the robot hand to be stopped at a fixed location depending on the surface condition of the object due to the linear heat.

That is, the output of the differentiator circuit 16 reverses its sign at the peak point of the characteristics of the photosensor output and the distance between the sensor and the object shown in FIG. It is detected by the zero cross detection circuit 28, and this signal causes the robot to stop.

Furthermore, other embodiments of the present invention will be described. This proximity sensor device is constructed by adding a peak value detection circuit 18 and a correction circuit 19 to the signal processing circuit shown in FIG. With this configuration, even if the characteristic of the reflective photosensor 1 is that the signal magnitude varies slightly depending on the surface condition of the object, the fluctuation in the signal magnitude caused by the difference in the surface condition of the object can be avoided. can be erased. This is very effective when the object that the robot should avoid colliding with is determined in advance.

In other words, slowly bring the robot hand closer to the object,
If the peak value of the output of the pig iron flow circuit 11 is detected and stored in the peak detection circuit 18, and the output of the rectifier circuit 1 in operation is normalized in the correction circuit 19 using this signal, the target Signal fluctuations due to differences in color or surface finish can be completely eliminated. It goes without saying that such a configuration can also be applied to the circuit shown in FIG. 4 or FIG. 5. Further, this signal correction may be performed by a computer.

Still another embodiment 1 of the present invention will be described. In this implementation, as shown in FIG.
The device is configured to know both the presence or absence of a gripped object and the distance between the finger 6 and the gripped object 7, as shown in FIG.

In other words, the opposing fingers 6 of the robot hand 5
Reflective photosensors 20 and 21f each having a light emitting diode and a phototransistor integrated are mounted opposite each other, and each photodiode is fl and fl, respectively.
The light is emitted using alternating currents with different frequencies, and all of these lights are received by each phototransistor, and the presence or absence of a signal of the frequency component of the light emitted by the other light emitting diode is used to detect the presence or absence of an object held between the fingers. at the same time,
This is a proximity sensor device used in robots that can determine the distance between a finger and an object it is holding based on the intensity of light emitted by its own light emitting diode.

With this configuration, the same sensor can simultaneously measure both the presence or absence of a gripped object between the fingers and the distance between the fingers and the gripped object. At the same time, it has the effect of reducing the number of lead wires that the robot hand must follow.

That is, this reflective photosensor 20° 21 is provided facing the finger 6.6 of the robot hand, and the light emitting diode of the reflective photosensor 21 has a frequency f.
An alternating current of frequency f2 is applied to the light emitting diode of the reflective photosensor 22, so that each light flux 22 and 23 reaches the phototransistor of the other.

However, when a gripped object 7 is present between the fingers 6, the light beams 22 and 23 are reflected by the surface of the gripped object 7 and enter the self-powered phototransistor.

Therefore, the presence or absence of the object 7 held between the fingers 6 can be detected based on the presence or absence of the 12 components of the phototransistor output of the reflective photosensor 2o and the fl component of the phototransistor output of the reflective photosensor 21. If the object to be held is made of a transparent material such as glass, both reflected light and transmitted light will be incident on the phototransistor, and each phototransistor will have a frequency fl and a frequency f.
The presence of the grasped object 7 can be detected depending on whether or not the two components No. 2 are included.

On the other hand, the means for measuring the distance to the held object using the reflected light beam from the held object 7 is constructed in the same manner as in the embodiment described above.

The signal processing circuit of this embodiment is as shown in FIG.
An AC power supply circuit 25 with a frequency of f2 is connected to the light emitting diode 24 of the reflective photosensor 20 whose one fin is provided at -6, and is adapted to emit a luminous flux 22, and a phototransistor 26 for light reception. has a frequency of 12
A selection amplification circuit 27 and a rectification circuit 28 that select only the signal of
and comparison circuit 29 are connected, and the proximity distance is the output end 30.
It is now detected from other finger 6
The reflective photosensor 21 provided in the
and the frequency fx of the light reception signal of the phototransistor 33
, fz, selective amplifier circuits 34, 35, rectifier circuits 36, 37, and comparison circuit 38. In other words, the presence or absence of the held object depends on the presence or absence of the output 39 of the rectifier circuit 37.
The distance between the fin -6 and the object 7 can be determined from the magnitude of the output 40 of the comparison circuit 38. Frequency 1 of this AC power supply circuit 32
1 and distance N1. The tuning frequencies of all the selective amplifier circuits 34 on the detection side are configured to be equal.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a part of the structure of the present invention, Fig. 2 is a partially cutaway front view of an example in which the invention is applied to a robot hand, and Fig. 3 is a signal processing circuit of the structure of the present invention. 4 and 5 are block diagrams of signal processing circuits showing all other embodiments of the present invention, FIG. 6 is a characteristic diagram, and FIG. 7 is a block diagram of another embodiment of the present invention. 8 and 9 are partially cutaway front views of another example in which the present invention is applied to a complete robot hand, and FIG. 10 is a block diagram of a signal processing circuit shown in another embodiment of the present invention. FIG. 2 is a block diagram of a processing circuit. 1.20.21 River reflection type photosensor, 2゜24.31
...Light emitting diode, 3,26,3311. Phototransistor, 9, 25. 32... AC power supply circuit, 10
, 27, 34. 35... selection amplification circuit, 11, 26,
36.37 River rectifier circuit, 12.29.38... Comparison circuit. Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 6
7 Figure 9Re, Listen Figure 9

Claims (1)

[Claims] a reflective photosensor having a light emitting element, a light receiving element and a metal;
It is fully equipped with an AC power source that causes the light emitting element of the reflective photosensor to emit light with an alternating current of frequency f, and a selective amplification circuit that extracts only the component of the frequency f of the luminous flux incident on the light receiving element of the reflective photosensor. Proximity sensor device with all the features.