WO1993022110A1

WO1993022110A1 - Safety apparatus

Info

Publication number: WO1993022110A1
Application number: PCT/JP1992/000578
Authority: WO
Inventors: Noboru Sugimoto; Kazumi Narita; Koichi Futsuhara
Original assignee: L. Engineering Co., Ltd.; The Nippon Signal Co., Ltd.
Priority date: 1992-05-01
Filing date: 1992-05-01
Publication date: 1993-11-11

Abstract

The present invention uses a sensor (10n ∩ 15n, 16) which transmits detection data of an object (M) by the decrease of an output signal energy, as a sensor for detecting people, and a sensor which transmits the detection data of the object (M) by the increase of the output signal energy, as a sensor (21 ∩ 26) for detecting a work. Driving of a mechanical movable portion is permitted only when the logical sum of the outputs from both sensors is a logical value 1 corresponding to the high energy state. In this way, the present invention provides a safety apparatus which has a high fail-safe function and can reliably secure safety of operators.

Description

Akira Itoda

, Safety device

- 〔Technical field〕

'' The present invention has a common workplace between industrial machines such as robots and humans.

'It relates to safety devices to ensure human safety in one space.

(Background technology)

Worker safety measures are extremely important in industrial machines, for example, spaces where robots and humans have a common workplace.

For this reason, in Japan, for example, the Industrial Safety and Health Regulations Article 150-4 requires that industrial robots be surrounded by safety fences.

By the way, in order for a robot to perform work, a work for machining must be carried into a work area of a robot movable part, for example, a robot arm.

In the case of a work system in which humans carry in the work, a door is usually installed at the entrance of the safety fence, and when the human opens the door to carry in the work, the drive power of the robot arm is cut off. By adopting the system, worker safety is ensured.

However, in large factories, etc., in order to streamline and improve the efficiency of the manufacturing process, a large number of robots surrounded by safety fences are placed on the work transfer path, and the work is automatically transferred to process the work continuously. As a result, the manufacturing process is being automated. In the case of a work system that automatically transports such a work, it is difficult to provide a door at the entrance of the safety fence. In such a case, a sensor etc. is installed at the entrance of the safety fence, and when a person passes through the entrance, it is detected by the sensor. By doing so, a system can be considered that determines that a human has entered the safety vehicle and shuts off the drive power of the robot arm in the safety vehicle (US Patent No. 4,309,696) .

However, in this case, it is possible to reliably discriminate the work automatically transferred one after another via the entrance from the person, and to keep the drive power of the arm of the mouth bot at 0 N when the work is carried in. It is required to prevent a decrease in work efficiency and ensure that when a human enters, the drive power of the robot arm is turned off to ensure human safety.

The present invention has been made in view of the above-mentioned problems, and can surely stop the power supply of the movable parts of the machine when a human enters the safety car surrounding the industrial machine. An object of the present invention is to provide a safety device that does not stop the power supply.

[Disclosure of the Invention]

For this reason, the present invention determines whether a passing object is a human or a work at an entrance and exit of a work space of a machine that processes a carried-in work, and a movable part of the machine when a human passes through the entrance and exit. A safety device for securing the safety of humans by generating a drive stop signal of the formula (1), wherein the output signal energy decreases when an object passing through the entrance is detected, and the output signal energy state is erroneously reduced in the event of failure. A first object detecting means for detecting humans, and a work detecting means configured to increase output signal energy when an object passing through the entrance is detected and to reduce output signal energy in a decreasing direction in the event of a failure. Second object detecting means, and logical sum calculating means for calculating a logical sum of an output signal of the first object detecting means and an output signal of the second object detecting means. The output signal energy state of the calculation means is expressed as logical values 1 and 0 as binary variables. At this time, the output of the logical value 0 corresponding to the low energy state is configured to be the drive stop signal of the mechanical movable section.

Thus, when an object exists at the entrance of the work space, the output signal energy of the first object detection means decreases. At this time, when the object is a work, the output signal energy of the second object detecting means increases, so that the logical sum calculating means uses the logical value corresponding to the high energy state based on the output of the second object detecting means. Generates 1 output. In this case, the object passing through the doorway is determined to be a work, and the incoming work is processed while the movable state is maintained without generating a drive stop signal for the mechanical movable part.

On the other hand, when the object is a human, the output signal energy of the second object detecting means does not increase, and the logical sum calculating means generates an output of a logical value 0 corresponding to the low energy state. In this case, the object passing through the doorway is determined to be a human, and a drive stop signal for the mechanical movable part is generated to stop the drive of the movable part, thereby ensuring human safety.

Specifically, the first object detecting means includes: a plurality of light emitting elements vertically arranged on one side of a wall face of the working space entrance facing each other; and a plurality of light emitting elements provided for each light emitting element and having different frequencies. A plurality of excitation circuits that excite the light emitting elements to generate light beams from the corresponding light emitting elements, and a plurality of excitation circuits arranged in the vertical direction facing the light emitting elements on the other side of the wall surface, and when no object exists. A plurality of light receiving elements for receiving a light beam from a facing light emitting element, and a plurality of filter circuits provided for each light receiving element and passing only a frequency signal of a light beam generated by the light emitting element facing the corresponding light receiving element. And a plurality of amplifier circuits for amplifying the output signal of each filter circuit, respectively. What is necessary is just to comprise a plurality of rectifying circuits for rectifying, and a logical product calculating means for calculating the logical product of the output signals of the plurality of rectifying circuits to generate an output, and for outputting a logical value of 0 when a failure occurs.

Further, the second object detection means includes: a transmission coil installed at the entrance and exit of the work space; an excitation circuit for exciting the transmission coil to generate an AC signal; and receiving an AC signal from the transmission coil. A receiving coil for generating an output signal, an amplification circuit for amplifying the output signal of the receiving coil, a rectifying circuit for rectifying the amplified output of the amplification circuit, and an output signal level of the rectifying circuit being a predetermined level A level test circuit that generates an output signal having a logical value of 1 corresponding to the high energy state in the above case, the output signal energy of the receiving coil increases based on the electromagnetic induction action when the work to be detected exists. What is necessary is just to make it the structure which the output signal level of the said rectifier circuit input into the said level determination circuit becomes more than predetermined level.

Further, it is desirable that the mark to be detected by the second object detecting means is made of metal.

Further, when the work to be detected is not metal, the work may be placed on a pallet, conveyed, and a metal may be attached to the pallet.

In addition, if the pallet is provided with a resonance circuit that resonates with the AC signal of the transmission coil, the detection sensitivity can be increased.

Further, the pallet may be provided with information transmitting means capable of transmitting various information related to a work processing operation of a machine to a receiving coil.

[Brief description of drawings]

Fig. 1 is a diagram that models a machine working system to which the present invention is applied. FIG. 2 is a simplified configuration diagram showing an example of the arrangement of a human detection sensor and a work detection sensor according to one embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of the human detection sensor.

FIG. 4 is a circuit configuration diagram of the work detection sensor.

FIG. 5 is a diagram showing a final output circuit of the safety device of the present embodiment. FIG. 6 is a view showing another embodiment of a pallet on which a work is placed.

[Best mode for carrying out the invention]

Hereinafter, embodiments of the safety device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of a work system to which the present embodiment is applied.

In the figure, the working space of each of the robots 1 and 2 including the working areas A and B (shown by a circle in the figure) of the arm that is a movable part is surrounded by safety fences 3 and 4. Entrances a and b are formed in the safety doors 3 and 4, respectively, and an entrance c is also formed in a safety door portion provided between the both-bottoms. Then, the work is carried into the safety fence 3 from the entrance a and is processed by the robot 1, then is carried into the safety fence 4 through the entrance c, is processed by the robot 2, and is processed through the entrance b. It is carried out. This work is automatically and continuously transferred by, for example, a belt conveyor.

The configuration of the safety device of the present embodiment applied to a case where the work is metal in such a work system will be described with reference to FIGS. 2 to 5. FIG. At each of the entrances a to c, a human detection sensor as first object detection means for human detection, described below, and a metal work A work detection sensor is provided as second object detection means for detecting M.

The human detection sensor is configured as follows.

On one wall of each entrance, vertically n light emitting elements 10, .10 ₂ .

10 is provided, and n light receiving elements 11! 11 ₂ ... 11 are provided in correspondence with the light emitting elements 10, 10 ₂ . Each light - emitting element lOi.li. · · · 10 _n is a third figure showing as different frequency f I. F 2. · · ■ excitation circuit of _{f n 12 122. ■ · · 12} " Excited and emits a light beam of the corresponding frequency ff ₂ ... F よう across the entrance. The light receiving element lh.11 ₂ ... Ll _n receives the light beam from the light emitting element 10 10 ₂ ... 10 when the object is not present, converts the light beam into an electric signal, and converts the converted output. Corresponding frequency f L f 2.

• Filter circuit that passes only f 13 13! .13 ₂ ..-13 _n Input to filter circuit 13..13 ₂ . , .14 ₂ ... 14 _n , and after being rectified by a rectifier circuit 15 15 ₂ ... -15 _π , is conventionally known (US Patent No. 4, 661, 880 US Patent No. 4, 667, 184, etc.). The AND gate 16, the respective rectifier circuits 15 15 _2. - - - 15 logic value 0 corresponding to a logic 1 value or a low energy state to Kashiwato to high engineering Nerugi伕態based on the level of the input signal from _η Generates output X. When all input signals from each rectifier circuit 15.15 _2. _{η become} higher than the power supply voltage of AND gate 16 (logic level of logic 1). Generates logical 1 output only.

Further, the work detection sensor is configured as follows. The transmitting coil 21 and the receiving coil 21 are positioned close to the workpiece passing through the entrance. The communication coil 22 is arranged. The coil width L of these two coils 21 and 22 is sufficiently longer than the wall thickness of the entrance and exit in the work transfer direction. The transmission coil 21 is excited by a signal generation circuit 23 as an excitation circuit. Further, the reception coil 22 receives the signal from the transmission coil 21 and when the work M is present, the energy of the reception output increases due to the electromagnetic induction action, and this output signal is input to the AC amplifier 24. . The amplified output of the AC amplifier 24 is rectified by the rectifier circuit 25, and then rectified by a conventionally known comparator (US Pat. No. 4,661,880, US Pat. No. 4, 757,417, etc.). The data is input to a level test circuit 26 using data. The level test circuit 26 generates an output Y having a logical value of 1 or a port-level logical value of 0 based on the level of the input signal from the rectifier circuit 25. When the work M exists at the entrance, the rectifier circuit 25 The output signal level from is above a predetermined level (logic level corresponding to logic value 1), and a logic 1 output is generated. It is desirable that the threshold level of the level verification circuit 26 be set higher than a level that is increased by the electromagnetic induction action of the metal member existing near the entrance and exit when the workpiece M does not exist.

Then, the output X of the AND gate 16 and the output Y of the level test circuit 26 are input to an OR gate 30, and based on the output Z of the OR gate, the output Z of the OR gate is set to a logical value of 1. At this time, the drive power of the robot arm is held in the ON state to permit driving, and the drive power of the robot arm is set to 0 FF when the output Z of the OR gate is a logical value 0. ■

Here, we will briefly explain what characteristics a sensor must have in order to construct a funnel-safe human detection sensor that can ensure human safety even in the event of a failure. First, there is a sensor with a structure in which the light beam emitted from the light-emitting element is always received by the light-receiving element and is interrupted by the presence of an object so that the light beam is not received by the light-receiving element. Consider a sensor with a structure in which the light beam that is not received is reflected by the object due to the presence of the object and received by the light receiving element (the receiving side increases the reception energy due to the presence of the object on the receiving side).

In this case, in the sensor having the latter structure, for example, in the case where the light emitting element fails and no light beam is generated, no detection signal of the object is generated even if the object is located at the place to be detected. For this reason, if a sensor having such a structure is used as a sensor for detecting a person, the output signal is in the absence of a person in the event of a failure despite the presence of a person, resulting in a dangerous error.

On the other hand, in the sensor having the former structure, if the light emitting element fails and no light beam is generated, an object detection signal indicating that an object is present at the place to be detected is generated. For this reason, a sensor with such a structure has an output signal form that indicates the presence of a human at the time of a failure, and will never make an error on the safe side nor make an error on the dangerous side.

Therefore, the human detection sensor according to the present embodiment having a configuration in which the output signal energy decreases when an object is detected is an output signal form indicating the presence of a human at the time of failure, and is a safe sensor.

In addition, the sensor for work detection is to maintain the π-bot movable part in the driving state when a work is detected, and to generate a movable part drive signal due to an increase in output signal energy when the work is detected. There is a need. In this way, when the output signal energy is lost at the time of failure, the drive signal of the robot movable part is not generated, and the movable part of the mouth is stopped, so that an error that is mistaken for humans on the safe side is made. It becomes an aile-safe sensor.

Next, the operation of the apparatus of this embodiment will be described for the entrance a. Note that the same applies to the entrances b and c, and a description thereof will be omitted.

First, when the work M passes through, for example, the entrance a, at least one or more light beams of the light emitting elements 10 10 ₂ ... -10 ° of the human detection sensor are blocked by the passage of the work M. As a result, the output signal of the filter circuit connected to the light receiving element corresponding to the light emitting element emitting the blocked light beam disappears, and the output signal of the rectifier circuit 15]. 15 ₂ . Cannot be a logical value 1, so that the output signal X of the AND gate 16 has a logical value 0.

On the other hand, in the work detection sensor, when the metal work M passes, the AC signal from the transmission coil 21 is strengthened by the electromagnetic induction action and received by the reception coil 22, and the energy of the output signal of the reception coil 22 increases. Great. The output signal with the increased energy of the receiving coil 22 is amplified by an AC amplifier 24 and rectified by a rectifier 25, and then input to a level detector 26. The level of the input signal from the rectifier circuit 25 is higher than a predetermined level due to an increase in the output signal energy of the receiving coil 22, and the output signal Y of the level test circuit 26 has a logical value 1.

Therefore, when the work M exists at the entrance, the output Z of the OR gate 30 for calculating the logical sum of the output signal X and the output signal Y becomes the logical value 1, and the robot movable part can be driven. It is kept in the state, and the work of the work can be performed.

On the other hand, when a person passes through the entrance a, the sensor for human detection is at least one of the light emitting elements 10 ι. 10 ₂ . Light beam passing by human The output signal of the rectifier circuit 1 ^. 152. · ·-15 „is not all logic value 1 and the output X of AND gate 16 is logic value 0.

In the work detection sensor, the electromagnetic induction does not occur when humans pass, and the reception energy of the reception coil 22 does not increase and the energy of the output signal of the reception coil 22 does not increase. Thus, the output signal level of the rectifier circuit 25 is lower than the predetermined level of the level test circuit 26, and the output signal Y of the level test circuit 26 becomes a logical value 0.

Therefore, when a person passes through the entrance, both the output signal X and the output signal Y have a logical value of 0, and the output signal Z of the OR gate 30 becomes the logical value and stops driving of the robot movable part. When a signal is generated, the moving parts of the robot stop and the safety of humans entering the safety area is secured.

Also, if a failure occurs in the human detection sensor such that a light beam is not emitted from the light emitting element, the output signal X of the AND gate 16 has a logical value of 0, ie, a signal indicating the presence of an object (human). When the peak M is no longer present, the output signal of the OR gate 30 becomes a logical value 0, and the robot movable section is immediately stopped. Also, in the work detection sensor, when a failure occurs, the energy of the output signal of the receiving coil 22 does not increase, and the output signal of the level test circuit 26 has a logical value of 0, that is, a signal form indicating that the work does not exist. The output of the OR gate 30 becomes the logical value 0, and the robot movable part stops.

As described above, the human detection sensor is configured to reduce the output signal energy due to the presence of the object, and the work detection sensor is configured to increase the output signal energy due to the presence of the object. If the drive of the robot movable part is controlled by the output, the robot It is possible to reliably discriminate between a human and a work entering the work space of a robot, to ensure human safety in a fail-safe configuration, and to prevent a reduction in work efficiency in a work system that automatically transports the work.

Also, the light emitting element

The light beam from 10 _n is radiated to the light receiving element 11 11 ₂ with a certain spread to the 11 „side, but the light emitting element 1 (^ .102. the 11 "fill evening circuit 13 teeth 13 ₂ to fill evening-ring output signal from the · · · 13." provided - with to have different frequencies in beams, light receiving element 11, .11 ₂ .... since also corresponds to the light beams from the light emitting elements other than the light-emitting element is incident Fi le evening circuit 13, .13 ₂ ... -. since 13 can Chikara' DOO this with filter-ring operation ", such It is possible to prevent the AND gate 16 from generating an erroneous output due to the reception of a light beam.

In the above embodiment, the case where the workpiece is made of metal has been described. However, when the workpiece is made of a material other than metal, the workpiece can be placed on a pallet as shown in FIGS. 6 (A) to 6 (C) and transported. Good.

FIG. 6 (A) shows an example of a pallet 40 in which metal m is embedded. In this case, when the pallet 40 on which the work is placed passes through the entrance a, the work detection sensor operates in the same manner as described above due to the electromagnetic induction effect of the metal m in the pallet 40, and the pallet 40 By detecting 40, peaks can be detected indirectly.

FIG. 6 (B) shows an example of a pallet 50 in which a resonance circuit including a coil 51 and a capacitor 52 that resonate with an AC signal generated from the transmission coil 21 is embedded.

In this case, when the pallet 50 on which the work is placed passes through the entrance a, the coil 51 in the pallet 50 receives the pallet 50 on the receiving coil 22 side. The transmission energy increases. Moreover, the AC signal energy transmitted from the transmission coil 21 to the reception coil 22 is greatly increased due to the resonance action of the resonance circuit of the capacitor 52 and the coil 51, so that the detection sensitivity of the pallet 50, in other words, the detection sensitivity of the workpiece is increased. FIG. 6 (C) shows an example of a pallet 60 in which a coil 61 and a transmitter 62 connected to the coil 61 are embedded (in this case, the transmission coil in FIG. 2). (There is no need for the signal 21 and the signal generation circuit 23).

In this case, information relating to the pallet 60 and the work M placed thereon, etc., such as information such as the type and number of the work, the number of the pallet, etc., which have been previously coded and stored. Is transmitted from the transmitter 62 as a code signal and transmitted to the receiving coil 22. <The information is processed as the processing information of the work on the pallet 60 and the pallet management information on the side of the mouth bot by the passage of the pallet 60. It is possible to build a transmission system.

Even when a workpiece is placed and transported on these pallets, if the metal m is not buried in the pallet 40 ゃ If the coil 51 in the pallet 50 has a disconnection failure, or if the pallet 60 In the event that the power supply (battery) of the transmitter 62 in the inside is exhausted and the transmission of the transmitter 62 is impossible, the output Y of the level verification circuit 26 does not become the logical value 1 and the pallet connects the entrance and exit. When passing, a driving trap signal for the robot's movable parts is generated, so it is a failsafe.

In this embodiment, a sensor using electromagnetic induction is shown as a work detection sensor. However, for example, a light emitting element and a light receiving element are arranged on the same side, and a light beam from the light emitting element is applied to a work or a palette. When the light is reflected by the light receiving element, the light A workpiece detection sensor configured to perform detection may be used. Also in this case, the work or pallet detection information is transmitted as an increase in the output signal energy of the light receiving element, which is the same as that using the electromagnetic induction action of the present embodiment. Further, a metal or a coil may be directly attached to a nonmetal object without using a pallet.

As described above, according to the present invention, a sensor configured to transmit object detection information as a decrease in output signal energy on the receiving side is used as a sensor for human detection, and object detection information is output from the output signal energy on the receiving side. A sensor configured to transmit as an increase is used as a peak detection sensor, and the drive and stop of the mechanical moving part are controlled based on the logical sum output of both sensors, so if there is no output signal in the event of a sensor failure, Since the moving parts of the machine always stop, it has excellent fail-safety and can ensure the safety of workers.

[Industrial applicability]

The present invention is directed to an automation work system for processing a work using an industrial machine such as a robot. In the automation work system, the safety of a worker working in a common workplace with the machine is remarkably improved, and an accident by the machine of the worker is prevented. Industrial applicability is great because it can be prevented before it happens.

Claims

The scope of the claims

(1) At the doorway of the working space of the machine that processes the loaded work, it is determined whether the passing object is a human or a work, and when a human passes through the doorway, the movable part of the machine is driven. In a safety device for generating a stop signal to ensure human safety, the output signal energy is reduced when an object passing through the entrance is detected, and the output signal energy state is erroneously reduced in the case of failure. A first object detecting means for human detection, and a second object detecting means configured to increase an output signal energy when detecting an object passing through the entrance and to reduce an output signal energy state in a decreasing direction when a failure occurs. An object detection unit; and an OR operation unit that performs an OR operation on an output signal of the first object detection unit and an output signal of the second object detection unit, the output signal of the OR operation unit being provided. When representing a logical value of 1, 0 energy state as the binary variables, the safety device, characterized in that the output of logic value 0 corresponding to a low energy-saving state and the drive stop signal of the machine moving part.

(2) The first object detecting means includes: a plurality of light emitting elements arranged in a vertical direction on one side of a wall face of the working space entrance facing each other; and a plurality of light emitting elements provided for each light emitting element at different frequencies. A plurality of excitation circuits for exciting the light emitting elements to generate light beams from the corresponding light emitting elements; and a plurality of excitation circuits arranged on the other side of the wall facing the light emitting elements in a vertical direction and facing when no object exists. A plurality of light receiving elements for receiving a light beam from the light emitting element that emits light, and a plurality of filter circuits provided for each light receiving element and passing only the frequency signal of the light beam generated by the light emitting element facing the corresponding light receiving element. , A plurality of high-frequency circuits that amplify the output signal of each filter circuit, and a rectification of the output signal of each amplifying circuit 2. A circuit comprising: a plurality of rectifier circuits; and a logical product operation means for calculating an AND of output signals of the plurality of rectifier circuits to generate an output, and at the time of a failure, outputting an error to a logical value 0. Safety device as described.

(3) The second object detection means includes: a transmission coil installed at the entrance and exit of the work space; an excitation circuit that excites the transmission coil to generate an AC signal; and receives an AC signal from the transmission coil. A receiving coil that generates an output signal from the receiving coil, a booster circuit that boosts the output signal of the receiving coil, a rectifier circuit that rectifies the amplified output of the booster circuit, and an output signal level of the rectifier circuit. A level verification circuit that generates an output signal with a logical value of 1 corresponding to the high energy state when the level is higher than or equal to a predetermined level, and the output of the receiving coil based on the electromagnetic induction action when the workpiece to be detected exists. 2. The safety device according to claim 1, wherein a signal energy is increased and an output signal level of the rectifier circuit input to the level verification circuit is equal to or higher than a predetermined level.

(4) The safety device according to (3), wherein the mark to be detected is made of metal.

(5) The safety device according to (3), wherein the work to be detected is placed and transported on a pallet, and a metal is attached to the pallet.

(6) The work to be detected is placed and transported on a pallet, and the pallet is provided with a resonance circuit that resonates with an AC signal of the transmission coil. Safety device.

(7) The work to be detected is placed and transported on a pallet, and the pallet is provided with information transmitting means capable of transmitting various information related to the work processing of a machine to a receiving coil. A contract that specializes in The safety device according to claim 3.