JP4337421B2 - Position measuring method and position measuring system for moving object - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a position measurement method and a position measurement system for measuring the position of an object moving within a monitoring area.
[0002]
[Prior art]
In recent years, the function of a work robot having a mobile function has increased, and many systems using the mobile robot have been developed. In order to control and manage the movement of the robot, it is indispensable to grasp the position of the robot moving in the work area. The robot position grasping technology includes a method in which the robot itself grasps the amount of movement based on the wheel rotation amount of its own moving carriage, and grasps the self position sequentially using its own initial position and amount of movement, the robot and the surrounding environment. There is a method of identifying the position of the robot by grasping the positional relationship with the fixed landmarks by a sensing technique between the robot using ultrasonic waves and light as a medium and the surrounding environment. The present invention relates to the latter technique.
[0003]
The conventional technique will be described with reference to FIG. The mobile robot 401 moves in a monitoring area, the timing pulse transmission unit 402 transmits a timing pulse serving as a reference time for position detection, and the timing pulse reception units 406-1 and 406-2 receive timing pulses. The ultrasonic transmitters 403-1 and 40-2 are configured to output ultrasonic waves having different frequencies fixedly installed in the monitoring area after receiving the timing pulse. is there.
[0004]
The ultrasonic receiving unit 404 receives ultrasonic waves of a plurality of frequencies and separates the frequencies, and the position detecting unit 405 recognizes the ultrasonic transmitting unit from the ultrasonic frequency and transmits the timing pulse transmission time. And a position in the monitoring area are detected from the reception time of the ultrasonic waves.
[0005]
The mobile robot 401 includes a timing pulse transmission unit 402, an ultrasonic reception unit 404, and a position detection unit 405.
(For example, refer to Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-35535 (page 3, FIG. 1)
[0007]
[Problems to be solved by the invention]
However, in the conventional configuration, the reflected wave from the structure arranged in the region is unavoidable due to the characteristics of the ultrasonic wave, and detecting this reflected wave causes an error in position detection. Had.
[0008]
In addition, when trying to identify information from reflected waves by software, a combination of multiple distance information is prepared from distance information obtained from multiple receivers with mixed detection values of direct and reflected waves. Reflection from combinations with low degree of matching, based on the degree of matching, between the combination of each distance information and the positional information of the number of combinations detected together with the positional information between the receiver and the shape information of the moving area Although it is possible to identify information by wave reception, it is not only difficult to implement due to the large amount of processing, but also if the number of reflected waves detected is greater than the number of direct waves, the reflected waves are removed. However, there is a problem that erroneous detection of the robot position is caused without being reliably performed.
[0009]
The present invention solves the conventional problem, and reduces the position detection error by eliminating disturbance information for position detection by reflected ultrasonic waves by a method that does not involve a slight apparatus configuration and calculation processing. An object of the present invention is to provide a position measuring device with improved detection accuracy.
[0010]
In order to solve the above-described problem, the present invention provides a position measurement device including a plurality of reception units arranged in advance at known positions in a monitoring area, a wireless transmission / reception unit for a position measurement device, and a position detection unit. ,
A method for measuring a position of a robot that moves in the monitoring area, comprising a wireless transceiver for a mobile robot, wherein the robot transmits an ultrasonic signal, an optical signal, and a position measurement request signal simultaneously; A second step in which the plurality of reception units receive the optical signal and the ultrasonic signal, and the position measurement device wireless transmission / reception unit receives a position measurement request signal; and the position detection unit includes the plurality of position detection units. A third step of determining that the ultrasonic signal is a direct wave when the optical signal received by the receiving unit is equal to or greater than a predetermined light intensity threshold, and in the third step, When it is determined that the ultrasonic signal is not a direct wave, the position measurement device wireless transmission / reception unit performs position measurement using a position measurement method that transmits a signal for requesting position change to the mobile robot wireless transmission / reception unit .
[0011]
By the method of the present invention, it is possible to perform position measurement while suppressing the influence of reflected waves of ultrasonic waves.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the invention described in the present invention will be described with reference to the drawings.
[0013]
(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a position measuring apparatus according to the first embodiment of the present invention.
[0014]
The mobile robot 101 moves within the monitoring area, the position measurement device 102 measures the position of the mobile robot 101 within the monitoring area, and the light source unit 104 includes the mobile robot 101 and the position measurement device 102. An optical signal for determining the presence or absence of a shielding object is output between the two and the ultrasonic oscillator 105 outputs an ultrasonic wave.
[0015]
Further, the mobile robot control unit 103 outputs a position measurement request signal that is a signal for requesting its own position measurement, and requests the light source unit 104 and the ultrasonic oscillation unit 105 to output optical signals and ultrasonic waves. The mobile robot wireless transmission / reception unit 106 transmits a position measurement request signal and receives position information of the mobile robot 101 measured by the position measurement apparatus 102.
[0016]
The receiving units 107-1 to 10-n (n is a natural number) are arranged in advance in known locations in the monitoring area and receive optical signals and ultrasonic waves. The oscillating unit 111 is a position of the mobile robot 101. The position detection unit 109 resets the receiving units 107-1 to 107-n and determines the distance from the mobile robot 101 based on the difference between the reception times of the optical signal and the ultrasonic signal. Is to be calculated.
[0017]
The map storage unit 110 stores map information including the shape of the monitoring area and the arrangement positions of the reception units 107-1 to 107-n in advance, and the wireless transmission / reception unit 108 measures the position from the mobile robot 101. A request signal is received, and an optical signal confirmation signal indicating reception of the optical signal and the calculated position information of the mobile robot 101 are transmitted.
[0018]
The mobile robot 101 includes a mobile robot control unit 103, a light source unit 104, an ultrasonic oscillation unit 105, and a mobile robot wireless transmission / reception unit 106. The position measurement device 102 includes reception units 107-1 to 107-n, oscillation units. 111, a position detection unit 109, a map storage unit 110, and a wireless transmission / reception unit 108.
[0019]
First, the operation of the mobile robot 101 will be described with reference to FIG.
[0020]
First, in S201, the mobile robot 101 moving in the monitoring area outputs a position measurement request signal for requesting the measurement of its own position by the mobile robot control unit 103 in order to determine its own progress method. The transmission request signal for outputting the optical signal and the ultrasonic signal is output to the mobile robot wireless transmission / reception unit 106, the light source unit 104, and the ultrasonic oscillation unit 105.
[0021]
Next, in S202, the mobile robot wireless transmission / reception unit 106 transmits a position measurement request signal to the position measurement device 102, the light source unit 104 outputs an optical signal, and the ultrasonic oscillation unit 105 outputs an ultrasonic signal. Is output.
[0022]
Next, in S203, when the mobile robot transmission / reception unit receives an optical signal confirmation signal indicating reception confirmation of the optical signal transmitted from the position measurement device 102, the process proceeds to S204. When the transmitted position change request signal for requesting the change of the position of the mobile robot 101 is received, the process proceeds to S206.
[0023]
Next, in step S <b> 204, the mobile robot wireless transmission / reception unit 106 receives a position information signal, which is the position information of the mobile robot 101 calculated by the position measurement device 102, and outputs the position information signal to the mobile robot control unit 103.
[0024]
Next, in S205, the mobile robot control unit 103 recognizes its current position from the position information signal.
[0025]
Next, in S206, the mobile robot control unit 103 changes the position of the mobile robot 101, and proceeds to S202 again.
[0026]
Next, the operation of the position measuring device 102 will be described.
[0027]
First, the wireless transmission / reception unit 108 receives a position measurement request signal from the mobile robot 101.
[0028]
Next, when the receiving units 107-1 to 10-n receive optical signals, the time measurement counters included in the receiving units 107-1 to 10-n are started. Note that the value of the time measurement counter is 0 until an optical signal is received.
[0029]
In addition, the position detection unit 109, when the wireless transmission / reception unit 108 receives the position measurement request signal and the reception units 107-1 to 107-n receive the optical signal, indicates an optical signal confirmation signal indicating that there is no shielding object. Is transmitted from the wireless transmission / reception unit 108 to the mobile robot 101, and the wireless transmission / reception unit 108 receives the position measurement request signal. However, if the reception units 107-1 to 107-n do not receive the optical signal, it indicates that there is an obstacle. The indicated position change request signal is transmitted from the wireless transmission / reception unit 108 to the mobile robot 101.
[0030]
When the position measurement device returns an optical signal confirmation signal to the mobile robot 101, the mobile robot 101 can recognize the presence or absence of an obstacle between the mobile robot 101 and the position measurement device 102, and the self-position. It is possible to avoid the shielding object.
[0031]
Here, in general, the optical signal has a characteristic that the reflectivity to the structure in the monitoring region such as the outer wall is overwhelmingly lower than the ultrasonic wave, and the signal intensity is greatly attenuated by diffusion from the structure. When there is an obstacle between the light source unit 104 of the mobile robot 101 and the receiving units 107-1 to 107-n of the position measuring device 102, the possibility of receiving the direct wave of the optical signal is to receive the direct wave of the ultrasonic wave. The optical signal intensity is extremely smaller than the direct optical reception intensity even if the optical signal intensity is reached.
[0032]
For this reason, when receiving part 107-1-n receives an optical signal, it is thought that possibility of receiving an ultrasonic direct wave is high.
[0033]
Next, when the receiving units 107-1 to 10-n receive ultrasonic waves, the time measurement counter is stopped.
[0034]
Next, the position detection unit 109 calculates distance information from the mobile robot 101 to the reception units 107-1 to 107-n by multiplying the value of the time measurement counter by the pulse interval of the continuous pulse signal and the sound speed.
[0035]
Note that the receiving units 107-1 to 10-n can eliminate the signal input of reflected light by setting the threshold value of the receivable light intensity to approximately the direct reception intensity within a finite moving distance range.
[0036]
Furthermore, by using the light source unit 104 as a point light source, the directivity of the light intensity distribution of the point light source is smaller than that of the ultrasonic oscillator, so that uniform threshold processing is performed in all directions in order to exclude reflected light. Even if it implements to, there are few azimuth | direction dependences and the equivalent effect can be acquired.
[0037]
That is, a path for direct ultrasonic waves is ensured between the mobile robot 101 and a receiving unit that can directly receive an optical signal having a specific intensity or higher, and it is easy to eliminate reflected ultrasonic waves.
[0038]
Next, the position detection unit 109 receives the distance information obtained from the plurality of reception units, the position information of each of the reception units 107-1 to 10-n stored in advance read from the map storage unit, the shape information of the moving area, In addition, the position of the mobile robot 101 can be detected by using the triangulation method.
[0039]
Next, the wireless transmission / reception unit 108 transmits the detected position information of the mobile robot 101 to the mobile robot 101 using a general wireless protocol.
[0040]
In addition, by using wireless communication, a position detection request from the position measurement device 102 is notified to the mobile robot 101, so that position detection starting from the position measurement device 102 can be easily realized.
[0041]
Next, FIG. 3 shows the configuration of the receiving unit 107.
[0042]
The receiving unit 107 is characterized by having an optical sensor 201 and an ultrasonic receiving unit 202 at close positions.
[0043]
The optical sensor 201 receives an optical signal transmitted by the mobile robot 101, the ultrasonic receiving unit 202 receives an ultrasonic signal transmitted by the mobile robot 101, and the threshold processing unit 203 By performing threshold processing on the signal intensity of the optical signal received by the sensor 201, a binary signal is output.
[0044]
In addition, the continuous pulse signal output from the common oscillator is input to all the receiving units 107-1 to 107-n, and the gate circuit unit 205 receives the continuous pulse signal by opening the gate at the rising edge of the binary signal. The counter unit 206 counts according to the continuous pulse signal input to the gate circuit unit 205 and receives the reset signal input from the position detection unit 109. This clears the counter value.
[0045]
The delay unit 204 sufficiently delays the rising edge of the ultrasonic signal in order to establish the count stop, and the count memory unit inputs from the counter unit 206 by the delayed rising edge of the ultrasonic signal. The counted value is stored, and the counter value is cleared by a reset signal input from the position detection unit 109.
[0046]
Next, FIG. 4 shows the procedure of the position detection process according to the present invention.
[0047]
First, in S <b> 301, the wireless transmission / reception unit 108 receives a position measurement request signal transmitted from the mobile robot 101.
[0048]
Next, when the optical sensor 201 receives an optical signal transmitted from the mobile robot 101 in S302, the process proceeds to S303, and when the optical signal is not received, the process proceeds to S311.
[0049]
In step S <b> 303, the position detection unit 109 outputs an optical signal confirmation signal from the wireless transmission / reception unit 108 after confirming reception of the optical signal and the position measurement request signal.
[0050]
Next, in S304, the counter unit 206 starts counting the counter for time measurement.
[0051]
Next, in S <b> 305, the ultrasonic receiving unit 202 receives an ultrasonic signal transmitted from the mobile robot 101.
[0052]
In step S <b> 306, the counter unit 206 stops the time measurement counter, and the counter memory unit 207 stores the counter value and outputs it to the position detection unit 109.
[0053]
In step S307, the position detection unit 109 calculates distance information from the mobile robot 101 to the reception units 107-1 to 107-n by multiplying the counter value by the pulse interval and the sound speed.
[0054]
Next, in S308, the position detection unit 109 determines whether the distance information for detecting the position of the mobile robot 101 is sufficient.
[0055]
Next, in S309, the position detection unit 109 determines the distance between the mobile robot 101 and the reception units 107-1 to 107-n, the position information of the reception units 107-1 to n stored in advance in the map information storage unit, and the shape of the movement area. The position of the mobile robot 101 is detected from the information.
[0056]
In step S <b> 310, the wireless transmission / reception unit 108 transmits the calculated position information of the mobile robot 101 to the mobile robot 101.
[0057]
Next, in S <b> 311, the position detection unit 109 confirms reception of the position measurement request signal, and outputs a position change request signal from the wireless transmission / reception unit 108 when an optical signal is not received.
[0058]
According to this configuration, by using the optical signal and the ultrasonic signal in combination, the reflected ultrasonic signal that increases as the monitoring area becomes complicated by performing position measurement using only the direct wave of the ultrasonic signal. Can prevent erroneous detection of the robot position.
[0059]
The same effect can be obtained by using the light source unit 104 as a heat source unit and the optical sensor 201 as a heat sensor.
[0060]
In the present embodiment, the position measurement system using a single mobile robot has been described, but the position measurement system using a plurality of mobile robots can also be changed by changing the ultrasonic frequency for each mobile robot. Similar effects can be obtained.
[0061]
【The invention's effect】
As described above, according to the position measurement apparatus and the mobile robot of the present invention, the position detection processing is performed using only the direct ultrasonic wave, thereby reducing the position detection error of the mobile robot and improving the position accuracy. Improvements can be made.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a position measuring apparatus according to a first embodiment of the present invention. FIG. 2 is a flowchart showing an operation of a mobile robot according to the first embodiment of the present invention. The figure which shows the structure of the position detection means by 1st Embodiment of this. [FIG. 4] The flowchart which shows the flow of the position detection process by the 1st Embodiment of this invention. [FIG. 5] The structure of the conventional position measuring apparatus. Figure [Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 Mobile robot 102 Position measuring device 103 Mobile robot control part 104 Light source part 105 Ultrasonic oscillation part 106 Mobile robot radio | wireless transmission / reception part 107-1 to n receiving part 108 Wireless transmission / reception part 109 Position detection part 110 Map storage part 111 Oscillation part 201 Optical sensor 202 Ultrasonic wave receiving unit 203 Threshold processing unit 204 Delay unit 205 Gate circuit unit 206 Counter unit 207 Counter memory unit

Claims (6)

A plurality of receiving units arranged in advance at known positions in the monitoring area;
A position measuring device including a wireless transmitter / receiver for a position measuring device and a position detecting unit,
A method for measuring a position of a robot that includes a wireless transceiver for a mobile robot and moves within the monitoring area,
A first step in which the robot simultaneously transmits an ultrasonic signal, an optical signal, and a position measurement request signal;
A second step in which the plurality of reception units receive the optical signal and the ultrasonic signal, and the position measurement device wireless transmission / reception unit receives a position measurement request signal;
A third step in which the position detection unit determines that the ultrasonic signal is a direct wave when the optical signals received by the plurality of reception units are equal to or greater than a predetermined light intensity threshold;
If it is determined in the third step that the ultrasonic signal is not a direct wave,
A position measurement method in which the position measurement device wireless transmission / reception unit transmits a signal requesting a position change to the mobile robot wireless transmission / reception unit. In the third step, when said ultrasonic signal is determined to be a direct wave, the use and the map information including the position of the front Symbol receiving unit, and a reception time difference of the optical signal and the ultrasonic signal The position measurement method according to claim 1, wherein position information of the robot is calculated. The position measurement method according to claim 1, wherein the robot further includes a light source unit configured by a point light source.
In the first step, a light source unit comprising a point light source transmits the optical signal,
A position measurement method in which the threshold is made uniform with respect to the optical signals received by the plurality of receivers in the third step. A system for measuring the position of a robot that moves in a monitoring area that simultaneously transmits an ultrasonic signal, an optical signal, and a position measurement request signal,
A plurality of receiving portions that are pre-positioned at a known position in the surveillance area for receiving the optical signal and the ultrasonic signal,
A position measuring device transceiver for receiving the position measurement request signal;
When the position measuring device transmitting / receiving unit receives the position measurement request signal and the optical signals received by the plurality of receiving units are equal to or greater than a predetermined light intensity threshold, the ultrasonic signal is directly A position detection unit that determines that the wave,
The position measuring system transmits and receives a signal for requesting a position change of the moving robot when the position detecting unit determines that the ultrasonic signal is not a direct wave.   When the position detection unit determines that the ultrasonic signal is a direct wave, the robot uses the map information including the arrangement position of the reception unit and the reception time difference between the optical signal and the ultrasonic signal. The position measurement system according to claim 4 which calculates position information. In the position measurement system according to claim 4 or 5,
The robot includes a light source unit configured by a point light source, the optical signal is transmitted from the light source unit, and the threshold is made uniform with respect to the optical signals received by the plurality of receiving units. Position measurement system.

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