JP4045243B2 - Equipment that moves autonomously - Google Patents

Description

The present invention relates to an object detection sensor that detects an object by light, and more particularly to an autonomously moving device having an object detection sensor that can prevent mutual interference when a plurality of objects are used.

  In recent years, robots used in general life have been realized, such as pet-type robots and self-propelled cleaners. One of the functions required for this type of robot is, for example, the ability to walk without human help, and the ability to clean the floor without obstacles without receiving human instructions. There is a function to move autonomously.

  In order to realize such a function, since it is necessary to move while avoiding the obstacle, an object detection sensor for detecting an object is necessary. As this type of object detection sensor, a sensor of a type that detects the distance to an object by performing triangulation using infrared light is often used. Specifically, the object detection sensor includes a light emitting element that emits pulsed light, and a light receiving element that receives the return light that is reflected by the light emitted from the light emitting element and returned to the object. The distance to the object is detected based on the light receiving position of the return light in the light receiving element. The robot provided with the object detection sensor changes the moving direction when the distance to the object detected by the object detection sensor is equal to or less than a predetermined distance so as to avoid the object that is an obstacle.

  However, when a plurality of robots equipped with the object detection sensor operate simultaneously, the object detection sensor of one of the plurality of robots receives light emitted from the object detection sensor of the other robot and detects the object. Is inaccurate. As a result, there is a problem that the one robot cannot avoid an obstacle. That is, when the detection areas of a plurality of object detection sensors overlap with each other, there is a problem that interference occurs between the plurality of object detection sensors.

  In order to solve this problem, conventionally, a light emitting element, a modulation unit that modulates light emitted from the light emitting element to a predetermined frequency, a light receiving element that receives light reflected by an object from the light emitting element, and the light receiving element An object comprising: a filter that extracts only a signal corresponding to light of the predetermined modulation frequency from signals from an element; and a signal processing unit that detects a distance to the object by processing the signal from the light receiving element A detection sensor has been proposed in which a first gate circuit is provided between the light emitting element and the modulation means, and a second gate circuit is provided between the light receiving element and the signal processing unit (for example, JP, 61-91589, A: Refer to patent documents 1).

  The conventional object detection sensor synchronizes the operations of the first gate circuit and the second gate circuit and intermittently emits light of a predetermined modulation frequency by the light emitting element at a predetermined period. The light receiving signals from the first and second light receiving elements are sent to the signal processing unit at the same period as the intermittent emission period of the light. Thereby, even when the detection areas of the plurality of object detection sensors overlap with each other, light from the light emitting elements of one object detection sensor is prevented from being received by the light receiving elements of the other object detection sensors. In addition, by sending a signal from the light receiving element to the signal processing unit only for the emitted light having a predetermined modulation frequency from the light emitting element included in the same object detecting sensor, the signals of the other object detecting sensors are erroneously transmitted. To avoid processing.

  However, the conventional object detection sensor has the following problems.

  (1) For mass-produced object detection sensors of the same model, it is difficult to vary the modulation frequency of the modulation means and the operation periods of the first and second gate circuits among all products. is there. Therefore, there is a possibility that object detection sensors having the same modulation frequency and operation cycle are used in the same detection area, so that the possibility of interference cannot be completely eliminated.

  (2) In order to prevent interference between different object detection sensors of different manufacturers, it is necessary to make the modulation frequency and the operation cycle different among all manufacturers, resulting in a great increase in labor and cost.

(3) When the modulation frequency is set to be different among all the object detection sensors, the entire range of the modulation frequency to be set is relatively wide. Therefore, the filter corresponding to the frequency in the wide range is This is necessary and causes an increase in cost.
JP 61-91589 A

Accordingly, an object of the present invention is to provide an autonomously moving device having an object detection sensor that can easily and reliably prevent interference even if detection areas overlap.

In order to solve the above problems, the autonomously moving device of the present invention is
A light emitting element that emits light;
A light receiving element that receives light emitted from the light emitting element and reflected by an object;
Distance calculating means for calculating a distance related to the object based on a signal output from the light receiving element;
An object detection sensor comprising: an erroneous calculation preventing means for preventing the distance calculating means from calculating an incorrect value of the distance;
The erroneous calculation prevention means is
A waiting time storage section in which a plurality of waiting time values are stored;
A waiting time input unit for inputting a predetermined waiting time different for each of the object detection sensors among the plurality of waiting times whose values are stored in the waiting time storage unit;
Reference signal receiving means for receiving a reference signal for the waiting time;
It said reference signal receiving means from receiving the reference signal, when the waiting time input the predetermined waiting time entered in elapses, look including an operation control means for operating the light emitting element and a light receiving element,
In the waiting time input unit, one of the waiting times can be selected by an operator's operation,
The reference signal is light emitted from a reference signal device .

  According to the above configuration, the light emitted from the light emitting element and reflected by the object is received by the light receiving element, and the distance with respect to the object is calculated by the distance calculating unit based on the signal output from the light receiving element. Calculated. The distance calculation means is prevented from calculating an incorrect value of the distance by the erroneous calculation prevention means. Accordingly, even when the plurality of object detection sensors are used in a state where the detection areas overlap, for example, the distances related to the objects can be accurately detected without interfering with each other.

Further , in the erroneous calculation preventing means, a plurality of waiting time values are stored in the waiting time storage unit, and a predetermined waiting time among the plurality of waiting times in which values are stored in the waiting time storage unit, Input to the waiting time input unit. When the predetermined waiting time elapses after the reference signal is received by the reference signal receiving means, the light emitting element and the light receiving element are operated under the control of the operation control means. Therefore, when a plurality of the object detection sensors are used in a state where the detection areas overlap, the respective waiting times are input to the waiting time input unit among the plurality of object detection sensors. Overlap of time during which the light emitting element and the light receiving element of the detection sensor operate is prevented. As a result, the light receiving element of one object detection sensor among the plurality of object detection sensors is prevented from receiving the light emitted from the light emitting elements of the other object detection sensors. It is effectively prevented to calculate an incorrect value.

In one embodiment of the autonomously moving device , the light receiving element also serves as the reference signal receiving means.

  According to the embodiment, since the light receiving element also serves as the reference signal receiving unit, an object detection sensor that can prevent erroneous calculation of a distance related to an object without adding a component for receiving the reference signal. Is obtained.

In one embodiment of the autonomously moving device , the reference signal receiving unit receives a standard time standard radio wave as the reference signal.

  According to the embodiment, the standard time standard radio wave is received as the reference signal, and the operations of the light emitting element and the light receiving element are controlled using the standard time standard radio wave as the reference signal. Therefore, it is possible to obtain an object detection sensor that can prevent erroneous calculation of a distance related to an object without providing another device that transmits a reference signal.

  The modulation means may modulate any characteristic such as emission frequency, emission intensity, emission phase, etc. of the light emitting element.

As described above, the autonomously moving device of the present invention has a light emitting element that emits light, a light receiving element that receives light emitted from the light emitting element and reflected by an object, and output from the light receiving element. A plurality of the object detection sensors include a distance calculation unit that calculates a distance related to the object based on the signal, and an erroneous calculation prevention unit that prevents the distance calculation unit from calculating an incorrect value of the distance. However, even when used in a state where the detection areas overlap, for example, the distance related to the object can be accurately detected without interfering with each other.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is a schematic diagram showing an object detection sensor according to a first embodiment of the present invention. The object detection sensor 1 of the present embodiment includes a light emitting element 2 that emits light, a light receiving element 3 that receives light emitted from the light emitting element 2 and reflected by the object, and a signal output from the light receiving element 3. And a distance calculating means for calculating a distance related to the object. The light emitting element 2 is formed of a semiconductor laser or a light emitting diode, and the light receiving element 3 is formed of a CCD (charge transfer element), a PSD (position detection element) or the like. The distance calculating means is formed by a CPU (Central Processing Unit) 5 and is based on a signal output from the light receiving element 3 according to a program stored in advance, and is obtained from the light receiving element 3 using a triangulation method. The distance to the object is calculated. That is, the light emitting element 2, the light receiving element 3, and the CPU 5 function as distance measuring operation means. The distance calculation means may be formed by a dedicated IC (integrated circuit). The distance calculating means may calculate the distance to the object by a method other than the triangulation method. For example, the direct light from the light emitting element and the light from the light emitting element are reflected by the object. The distance may be detected based on the optical path difference from the reflected light.

  The object detection sensor 1 includes the erroneous calculation preventing means of the present invention. The erroneous calculation preventing means includes a ROM (read only memory) 6 as a waiting time storage unit in which a plurality of waiting time values are stored in advance, and a predetermined waiting time value among a plurality of waiting time values stored in the ROM 6. It has a rotary switch 8 as a waiting time input unit for inputting a waiting time, and a reference signal receiving means for receiving a reference signal. The rotary switch 8 can select one of a plurality of preset waiting times by the operation of the operator.

  FIG. 2A is a schematic diagram showing the rotary switch 8. One of eight different waiting times can be selected by matching the position of the knob with any of the first pattern to the eighth pattern. It has become.

  The ROM 6, the rotary switch 8 and the CPU 5 form a start time control means.

  The light receiving element 3 also serves as the reference signal receiving means. Further, a switch 11 formed of a transistor or a relay is provided in a power supply line for supplying power to the driver 9 of the light emitting element 2, and the CPU 5 controls the on / off of the switch 11. ing.

  The object detection sensor 1 having the above configuration is mounted on a device having a function of moving autonomously, such as a fully automatic vacuum cleaner or a pet-type robot.

  FIG. 2B is a schematic diagram illustrating a state in which a plurality of the object detection sensors 1 operate in one room. In this room, first to third devices 21, 22, and 23 that are provided with the object detection sensor 1 and move autonomously are arranged. A reference signal device 25 that emits light as a reference signal is installed on the ceiling of the room. Since the first to third devices 21, 22, and 23 operate simultaneously in the room, the object detection sensors 1 provided in the devices 1, 2, and 3 respectively have detection areas that overlap each other. Will work with. As shown in FIG. 2B, the object detection sensor 1 of the first device 21 has the first pattern selected by the rotary switch 8, and the object detection sensor 1 of the second device 22 is the second by the rotary switch 8. A pattern is selected, and the third pattern is selected by the rotary switch 8 in the object detection sensor 1 of the third device 23.

  The object detection sensors 1 of the first to third devices 21, 22, 23 receive the light emitted from the reference signal device 25 by the light receiving element 3 and detect the reference signal. FIG. 3 is a schematic diagram showing the state of the distance measuring operation in time series for each object detection sensor 1 provided in the first to third devices 21, 22, and 23. As shown in FIG. 3, the object detection sensor 1 of the first device 21 starts a ranging operation when a waiting time T1 corresponding to the first pattern has elapsed from the time T01 when the reference signal is detected. That is, the CPU 5 switches the power line switch 11 from OFF to ON, supplies power to the driver 9 of the light emitting element 2, and activates the light emitting element 2. As a result, light is emitted from the light emitting element 2, and reflected light obtained by reflecting the light on the object is received by the light receiving element 3. Based on the output from the light receiving element 3, the CPU 5 as the distance calculating means calculates a distance related to the object. Such a distance measuring operation of the object detection sensor 1 of the first device 21 is performed over a predetermined distance measuring period T11. When the distance measuring period T11 elapses, the power line switch 11 is switched from on to off under the control of the CPU 5, the light emitting element stops emitting light, and the distance measuring operation ends. Thus, the CPU 5 also functions as an operation control unit.

  The object detection sensor 1 of the second device 22 starts the ranging operation when the waiting time T2 corresponding to the second pattern has elapsed from the time T01 when the reference signal is detected. At this time, the distance measuring operation of the object detection sensor 1 of the first device 21 is finished. In the object detection sensor 1 of the second device 22, the CPU 5 switches the power line switch 11 from OFF to ON to activate the light emitting element 2, and based on the output from the light receiving element 3, Calculate the distance for. The distance measuring operation of the object detection sensor 1 of the second device 22 is performed over a predetermined distance measuring period T21. When the distance measuring period T21 has elapsed, the switch 11 is switched from on to off under the control of the CPU 5, and the distance measuring operation is completed.

  When the waiting time T3 corresponding to the third pattern has elapsed from the time T01 when the reference signal is detected, the object detection sensor 1 of the third device 23 performs a ranging operation under the control of the CPU 5 as an operation control means. To start. At this time, the distance measuring operation of the object detection sensor of the second device 22 is finished. The distance measuring operation of the object detection sensor of the third device 23 is performed over a predetermined distance measuring period T31. When the distance measurement period T21 elapses, the distance measurement operation is ended under the control of the CPU 5.

  After the object detection sensors 1 of the first to third devices 21, 22, 23 perform a distance measuring operation, a reference signal is transmitted again from the reference signal device 25, and each object detection that has received this reference signal The sensor 1 performs the same operation as the above operation again.

  That is, the object detection sensor 1 of the first device 21 performs a ranging operation over the ranging period T11 after the waiting time T1 has elapsed from the time T02 when the reference signal is detected. In addition, the object detection sensor 1 of the second device 22 performs a ranging operation over a ranging period T21 after the waiting time T2 has elapsed from the time T02 when the reference signal is detected. In addition, the object detection sensor 1 of the third device 23 performs a ranging operation over a ranging period T31 after a waiting time T3 has elapsed from the time T02 when the reference signal is detected.

  As described above, the object detection sensors 1 of the first to third devices 21, 22, 23 are based on the reference signals transmitted from the reference signal device 25, from different start times T 1, T 2, T 3. The distance measuring operation is performed only during a predetermined distance measuring period T11, T21, T31. The start times T1, T2, and T3 are periods between the start times T1, T2, and T3 immediately before and after the predetermined distance measurement periods T11, T21, and T31. Is set to be longer. Therefore, the distance measuring operations of the object detection sensors 1 are not performed overlapping each other. As a result, each of the object detection sensors 1 is reliably prevented from erroneously calculating the distance related to the object by receiving light from the light emitting elements of the other object detection sensors 1 even though the detection areas overlap each other. The That is, the plurality of object detection sensors 1 are prevented from interfering with each other's distance measuring operations.

  When the devices 21, 22, and 23 are devices whose movement speed changes like a self-propelled robot, when the movement speed is slow, for example, according to the movement speed of the devices 21, 22, and 23, The number of times that the object detection sensor 1 performs the distance measurement operation may be reduced, or the distance measurement period may be shortened. Thereby, the power consumption of the object detection sensor 1 can be reduced.

  In the above embodiment, the three object detection sensors 1 are operated in a state where the detection areas are overlapped. However, the object detection sensors 1 are overlapped up to eight patterns which can be selected by the rotary switch 8. Can work. In this case, eight different waiting times are set corresponding to the eight patterns. The eight waiting times are set so that the period between the waiting times is longer than the distance measurement period during that period. The transmission interval of the reference signal is set longer than a period obtained by adding all the distance measurement periods.

  The rotary switch 8 is not limited to eight patterns corresponding to the waiting time, and any number of patterns may be selected.

  The rotary switch 8 may be a dip switch.

  Further, although the light receiving element 3 also serves as a reference signal receiving means, a light receiving element for receiving light from the reference signal device 25 may be provided separately. Further, the reference signal may be transmitted by radio waves, and the radio waves may be received by an antenna as a reference signal receiving unit.

  FIG. 4A is a schematic diagram illustrating the rotary switch 18 provided in the object detection sensor of the second embodiment. The rotary switch 18 of the object detection sensor can set a waiting time from the time when the reference signal is detected until the distance measurement operation is started by selecting one of the first pattern to the seventh pattern. In addition, the output of the reference signal can be set. That is, since this object detection sensor can transmit a reference signal by setting the rotary switch 18, as shown in FIG. 4B, a reference signal device for transmitting the reference signal is not installed in the room. A plurality of object detection sensors can be operated. The object detection sensor of the present embodiment has the same configuration as the object detection sensor of the first embodiment except that a reference signal can be transmitted. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4B, the object detection sensor of the first device 31 is set to output a reference signal by the rotary switch 18, and the object detection sensor of the second device 32 is the first pattern of the rotary switch 18. Is selected, and the object detection sensor of the third device 33 has the second pattern selected by the rotary switch 18.

  The object detection sensor of the first device 31 emits light as a reference signal from the light emitting element 2 under the control of the CPU as the reference signal control means. When the transmission of the reference signal is completed, a distance measurement operation is performed under the control of the CPU as the operation control means after a predetermined waiting time has elapsed. This distance measuring operation is performed over a predetermined distance measuring period, and the distance measuring operation is terminated with the end of the distance measuring period. The waiting time may be deleted and the ranging operation may be started simultaneously with the completion of the transmission of the reference signal.

  The object detection sensor of the second device 32 receives light as a reference signal emitted from the object detection sensor of the first device 31 by a light receiving element, and detects the reference signal. Thereafter, when a waiting time corresponding to the first pattern elapses, a ranging operation is started under the control of the CPU as the operation control means. When the predetermined distance measurement period ends, the object detection sensor of the second device 32 ends the distance measurement operation under the control of the CPU.

  The object detection sensor of the third device 33 receives light from the object detection sensor of the first device 31 and detects a reference signal. Thereafter, when a waiting time corresponding to the second pattern elapses, a ranging operation is started under the control of the CPU as the operation control means. When the predetermined distance measurement period ends, the object detection sensor of the third device 33 ends the distance measurement operation under the control of the CPU.

  Thus, since the object detection sensor of the first device 31 has a function of transmitting the reference signal, it is not necessary to install a device for transmitting the reference signal separately from the object detection sensor. Therefore, interference between a plurality of object detection sensors can be easily prevented only by the object detection sensor.

  In the above embodiment, the object detection sensors of the second and third devices 32 and 33 can set the output of the reference signal by the rotary switch 18, but the object detection sensor of the first device 31. Only the reference signal output may be settable. That is, it is only necessary that one of the plurality of object detection sensors having overlapping detection areas can output the reference signal.

  FIG. 5 is a diagram illustrating a signal including a reference signal received by the object detection sensor according to the third embodiment. The object detection sensor of this embodiment uses a standard radio wave of Japan standard time as a reference signal. As shown in FIG. 5, the standard radio wave is composed of a 60-bit pulse signal having a period of 60 seconds, and 55% of the rising edge of each pulse signal coincides with the standard time second.

  The object detection sensor of the present embodiment includes a reference signal receiving unit including an antenna that receives the standard radio wave and a pulse detection unit that detects the pulse from a signal received by the antenna. The reference signal receiving means is set so as to recognize a predetermined pulse included in the pulse signal of the standard radio wave as a reference signal. The object detection sensor of this embodiment has the same configuration as the object detection sensor 1 of the first embodiment except for the reference signal receiving means.

  A plurality of devices provided with the object detection sensors having the above-described configuration are operated in a state where the detection areas overlap each other. Then, each of the plurality of object detection sensors detects a predetermined pulse included in the standard radio wave as a reference signal. Each object detection sensor performs a distance measurement operation for a predetermined distance measurement period after a predetermined waiting time elapses after receiving the reference signal. Similar to the first embodiment, the waiting time is set to a different time between the object detection sensors, and the distance measurement period includes the waiting time immediately before the distance measurement period starts and the measurement time. It is shorter than the period between the waiting period immediately after the end of the distance period. Therefore, the plurality of object detection sensors can effectively prevent the distance measuring operations from interfering with each other.

  Moreover, since the object detection sensor of this embodiment detects a reference signal based on the standard time standard radio wave, a device for transmitting the reference signal is not necessary. Therefore, an object detection sensor capable of reliably preventing interference can be obtained with a simple configuration.

  In addition, although the object detection sensor of the said embodiment uses the standard time radio wave of Japan, you may use the standard time radio wave of the said country according to the country used.

  An object detection sensor according to a fourth embodiment of the present invention includes a modulation unit that modulates light emitted from a light emitting element. The modulation unit modulates the modulation pattern of the light emitting element among a plurality of modulation patterns. ing. Specifically, the capacitance value and resistance value of a plurality of capacitors can be selected by a rotary switch, and the time constant of the modulation means can be changed by changing the capacitance value and resistance value of the capacitor by operating this rotary switch. The oscillation frequency is changed to change the modulation pattern. A filter is provided as an extracting unit that extracts only a signal corresponding to the light of the modulation pattern from signals received and output by the light receiving element and sends the signal to the CPU as the distance calculating unit. The modulation means, the rotary switch, and the filter constitute the erroneous calculation prevention means of the present invention. In the fourth embodiment, parts having the same functions as those in the first embodiment will be described using the same reference numerals.

  The rotary switch has the same form as the rotary switch 8 of the object detection sensor of the first embodiment of FIG. 2A, and the capacitance value and resistance value of the capacitor different from each other are set corresponding to each selectable pattern. Has been.

  When a plurality of devices provided with the object detection sensors are used in one room, the patterns selected by the rotary switches of the plurality of object detection sensors are set to be different from each other. Thereby, the light emitting elements 2 of the plurality of object detection sensors emit light having different modulation patterns. Even if a plurality of lights having different modulation patterns are received by the light receiving element 3 of one object detection sensor, only the output corresponding to the light modulated by the modulation pattern of the object detection sensor by the filter is received by the light receiving element 3. It is taken out from the element 3. The extracted output is sent to the CPU 5, and the CPU 5 calculates the distance to the object. Therefore, even if a plurality of the object detection sensors of the present embodiment operate at the same time in a state where the detection areas overlap, interference of the ranging operation is effectively prevented.

  Further, since the filter only needs to extract the light output of the modulation pattern from the light receiving element 3 for the range of the modulation pattern that can be selected by the rotary switch, for example, it corresponds to signals in a wide frequency band as in the prior art. It doesn't have to be a filter. Therefore, since a cheaper filter than the conventional one can be used, the cost reduction of the object detection sensor can be measured.

  Further, since the modulation pattern can be selected by the rotary switch so as not to overlap between the object detection sensors, interference can be easily and reliably prevented between the object detection sensors having overlapping detection areas. it can.

  In the above embodiment, the rotary switch is used to change the modulation pattern. However, other switches such as a dip switch may be used.

  Moreover, although the said modulation means changed the oscillation frequency of the said light emitting element, you may modulate the light emission intensity, the light emission phase, etc. of the said light emitting element. In this case, the extraction means may use a circuit or the like that extracts a signal of the predetermined modulation pattern according to the characteristic to be modulated.

It is the schematic which shows the object detection sensor of 1st Embodiment of this invention. It is a schematic diagram which shows a rotary switch. It is the schematic which showed a mode that several object detection sensor operate | moved in one room. It is a figure which shows a mode that the object detection sensor of 1st Embodiment of this invention operate | moves. It is the schematic which shows the rotary switch with which the object detection sensor of 2nd Embodiment is provided. It is the schematic which showed a mode that several object detection sensor operate | moved in one room. It is a figure which shows the signal containing the reference signal which the object detection sensor of 3rd Embodiment receives.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Object detection sensor 2 Light emitting element 3 Light receiving element 5 CPU
6 ROM
8 Rotary Switch 9 Light Emitting Element Driver 11 Light Emitting Element Power Line Switch 12 Light Receiving Element Power Line Switch

Claims (3)

A light emitting element that emits light;
A light receiving element that receives light emitted from the light emitting element and reflected by an object;
Distance calculating means for calculating a distance related to the object based on a signal output from the light receiving element;
An object detection sensor comprising: an erroneous calculation preventing means for preventing the distance calculating means from calculating an incorrect value of the distance;
The erroneous calculation prevention means is
A waiting time storage section in which a plurality of waiting time values are stored;
A waiting time input unit for inputting a predetermined waiting time different for each of the object detection sensors among the plurality of waiting times whose values are stored in the waiting time storage unit;
Reference signal receiving means for receiving a reference signal for the waiting time;
It said reference signal receiving means from receiving the reference signal, when the waiting time input the predetermined waiting time entered in elapses, look including an operation control means for operating the light emitting element and a light receiving element,
In the waiting time input unit, one of the waiting times can be selected by an operator's operation,
The autonomously moving device, wherein the reference signal is light emitted from a reference signal device . The device of claim 1 ,
The autonomously moving device, wherein the light receiving element also serves as the reference signal receiving means. The device of claim 1 ,
The apparatus for autonomously moving, wherein the reference signal receiving means receives a standard time standard radio wave as the reference signal.

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