JP3419031B2 - Laser ranging sensor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser distance sensor capable of outputting a distance value of a displacement value of an object to be measured. 2. Description of the Related Art Conventionally, distance measurement signals obtained by operating a plurality of optical heads are sequentially taken into one signal processing circuit, and a displacement amount with respect to a reference position is calculated for each optical head. , there was a laser ranging sensor to perform distance measurement have based Dzu each displacement amount obtained (Japanese Patent Application No. 3-31353
No. 2). In a conventional laser distance measuring sensor, distance measurement data from the optical head is taken into a signal processing circuit by switching the circuit of the optical head. Since the distance measurement value data of the optical head not connected to the signal processing circuit is not required, the circuit of the optical head not connected does not need to be operating. When the distance measuring operation is repeated at a high speed, the speed of switching of the optical head is also required to be high.
However, when switching at high speed, if the circuit of the optical head that is not connected to the signal processing circuit is not operated,
The circuit of the optical head when it is connected becomes unstable, causing an error in the distance measurement value. Since it is necessary to perform high-speed ranging while keeping the circuit of the optical head stable, the optical head connected to the signal processing circuit and the optical head not connected to the internal circuit include:
Repeat the distance measurement operation. However, if the internal circuits of the two optical heads operate the same, the two optical heads will emit light simultaneously. When the two optical heads project light to a position close to each other, the first head moves to a position where the second optical head projects light from the position where the first head projects light. The reflected light whose center of gravity is offset is received. On the other hand, the second head receives reflected light whose center of gravity is shifted from the position where the second head projects light to the position where the first optical head projects light. As a result, there is a problem that an error occurs in the distance measurement value of both optical heads. When the distance measurement target object is slowly displaced and the distance measurement accuracy is more important than the high-speed distance measurement, the distance measurement time may take a long time. Therefore, it is necessary to perform the distance measurement with high accuracy. [0007] In such a case, laser ranging sensor is projected only the optical head that is connected to the signal processing circuit, an optical head which is not connected to the signal processing circuit, not to the light projecting distance measurement Action may be performed. It suffices if both optical heads can simultaneously perform light projection and alternate light projection. However, in the case of alternately projecting light, it is necessary to extend the distance measurement time per time in comparison with the case of simultaneously projecting light in order to wait for the internal circuit of the optical head to stabilize. In the conventional laser distance measuring sensor, at the stage of transmitting data from the distance measurement value calculation CPU to the distance measurement value output CPU, the bus switching circuit uses the signal from the distance measurement value output CPU to execute the distance measurement value calculation CPU. And the distance measurement value output CPU memory are connected. After the distance measurement value calculation CPU writes the data in the distance measurement value output memory, the bus switching circuit switches the bus again, and the distance measurement value output CPU memory A distance measurement value output CPU is connected, and a method is used in which data required by the distance measurement value output CPU is read from a memory for the distance measurement value output CPU. CPU for distance measurement calculation by switching buses
The time for connecting the distance measurement value output CPU memory is specified by the bus switching circuit. Therefore, there is a problem that, when extending one ranging time, two systems of bus switching circuits having different switching times are required. It is an object of the present invention to alternately emit light from a distance measuring mode (hereinafter, referred to as a standard mode) in which the internal circuits of the two optical heads operate in the same manner and perform high-speed distance measuring. An object of the present invention is to provide a laser distance sensor capable of selecting both distance measurement modes of a distance measurement mode (hereinafter referred to as a mutual interference prevention mode) for preventing mutual interference. SUMMARY OF THE INVENTION The present invention is directed to a method for projecting light onto an object to be measured, receiving reflected light from the object to be measured, detecting the center of gravity of the received reflected light, Two optical heads for outputting signals, a position signal processing unit for amplifying the position signal from each of these optical heads and converting the signal into a digital signal by A / D conversion, and a digital signal from the position signal processing unit Rank
Based on location signal, the distance measurement value calculating CPU for calculating a distance value of the distance measurement object receives a distance measurement value of the calculated distance measurement target object in the distance measurement value calculating CPU, measurement output to the outside and距値output CPU, a memory for distance measurement value calculating CPU for storing programs and data of the distance measurement value calculating CPU, used to store programs and data of the distance measurement value output CPU
The distance measurement value calculation CPU and the distance measurement value output CPU are common.
A memory for a distance measurement value output CPU including a region to be used, a bus for connecting a distance measurement value calculation CPU and a memory for a distance measurement value CPU in response to a signal from the distance measurement value output CPU, and a distance measurement value CPU; An internal circuit of two optical heads in a laser ranging sensor having a bus switching circuit for switching a bus connecting a memory for a ranging value output CPU in an opposite phase.
In the ranging mode where the same operation is possible and high-speed ranging is possible
According to a signal from the ranging value output CPU, the bus switching circuit connects the ranging value calculation CPU and the ranging value output CPU memory, and the ranging value calculation CPU writes data to the ranging value output CPU memory. I then, performs bus-cutting exchange example circuit is a bus switching again, connects the distance measurement value output memory for the CPU distance measurement value output CPU, the required data is the distance measurement value output CPU from the memory for the distance measurement value output CPU is Two lights while reading
Interfere with each other by alternately projecting optical heads
In the case of the distance measurement mode for preventing the
Sends a bus switching timing signal to the distance measurement value output CPU.
When this is received by the distance measurement value output CPU,
Bus to the bus switching circuit by timing the reference signal
Outputs a switching signal, which is accepted by the bus switching circuit
Then, the bus is switched and the distance measurement value calculation CPU and the distance measurement value
Connect the output CPU memory, and the distance measurement value calculation CPU
After writing data to the value output CPU memory,
The switching circuit switches the bus again and outputs the distance value output CP.
U memory and ranging value output CPU are connected, and ranging value output C
Data required by the distance measurement value output CPU is read from the PU memory.
It is characterized by taking out. According to the laser distance measuring sensor of the present invention,
When high-speed ranging with two optical heads is required, and
In a laser distance measuring sensor capable of preventing a mutual interference when the lights of two optical heads interfere with each other, the operation of the internal circuits of the two optical heads is the same, so that high-speed ranging is possible. Distance measurement mode (standard mode)
By alternately projecting the two optical heads, it is possible to select both distance measurement modes of a distance measurement mode for preventing mutual interference (mutual interference prevention mode). The circuit used in the method can be shared and simplified. Further, a distance measurement value calculation C requiring high-speed calculation
The distance measurement value data can be reliably transmitted from the distance measurement value calculation CPU to the distance measurement value output CPU without hindering the operation of the PU. Embodiments of the present invention will be described below with reference to the drawings. The laser distance measuring sensor of the present invention has a distance measuring value calculation C
A bus switching timing signal can be sent from the PU to the distance measurement value output CPU. In the standard mode, the distance measurement value output CPU sends a signal to the bus switching circuit when necessary, and the distance measurement value Receives data from the calculation CPU. In the mutual interference prevention mode, the distance measurement value calculation CPU sends a bus switching timing signal to the distance measurement value output CPU, and the distance measurement value output CPU sends a signal to the bus switching circuit. The distance measurement value data is transmitted from the calculation CPU to the distance measurement value output CPU. Then, a bus switching timing signal is sent from the distance measurement value calculation CPU to the distance measurement value output CPU, and the distance measurement value calculation CPU
It is configured so that the timing at which the distance measurement value data is transmitted from U to the distance measurement value output CPU can be defined. The time required for the distance measurement value calculation by the distance measurement value calculation CPU is the same whether the two optical heads simultaneously emit light or alternately emit light. When light is alternately projected, the distance measurement value calculation CPU waits until the internal circuit of the optical head is stabilized, and then calculates the distance measurement value. Considering from the start of the distance value calculation, the distance value output C from the distance value calculation CPU
The time until the distance measurement value is transmitted to the PU is the same in both the standard mode and the mutual interference prevention mode. For this reason, if the ranging value calculation CPU transmits the timing to start the ranging value calculation to the ranging value output CPU, the ranging value output CPU sends a signal to the bus switching circuit and the ranging value thereafter. The same transmission operation can be performed in the standard mode or the mutual interference prevention mode.
In other words, there is no need to prepare two bus switching circuits depending on the length of the distance measuring time. If a bus switching timing signal line is added to the circuit of the conventional laser distance measuring sensor, operation in either the standard mode or the mutual interference prevention mode is possible. Can be executed by the same circuit. The details will be described below. FIG. 1 is a system configuration diagram. Two optical heads 2 and 3 are attached to the object 1 to be measured.
, And each of the optical heads 2 and 3 sends a distance measurement value signal to the position signal processing unit 5. By the changeover switch 4 between the optical heads 2 and 3 and the position signal processing unit 5, the position signal processing unit 5 selects the optical heads 2 and 3 that receive the position signal. In the position signal processing section 5, the optical heads 2, 3
Is converted into digital data by amplifying and A / D converting the position signal obtained from. The digitized position signal is passed to the distance measurement value calculation CPU 6. Distance measurement value calculation CPU6
Reads the digitized position signal and calculates the distance measurement value of each of the optical heads 2 and 3. The execution procedure and data for the calculation are stored in the memory 7 for the distance calculation CPU.
It is. It is the distance measurement value output CPU 8 that receives the data calculated by the distance measurement value calculation CPU 6 and outputs it to the outside. The execution procedure and data when the distance measurement value output CPU 8 executes the calculation are stored in the distance measurement value output CPU memory 9.
Is stored in Distance value output CPU memory 9, the distance measurement value output CPU8 contains space for a Common and distance value calculation CPU 6. By using the common area, the distance value calculated by the distance value calculation CPU 6 is sent to the distance value output CPU 8. Since the address of the ranging value output CPU memory 9 is shared by the ranging value calculation CPU 6 and the ranging value output CPU 8, a switch between the ranging value calculation CPU 6 and the ranging value output CPU memory 9 is provided. The common area is used by switching the bus so that the switch 13 located between the CPU 13 and the distance measurement value output CPU 8 and the distance measurement value output memory 9 has the opposite phase. The bus switching circuit 10 performs the above-described bus switching. This bus switching circuit 10
Upon receiving a signal from the distance measurement value output CPU 8, the bus is switched for a fixed time. Normally, the distance value output CPU 8 and the distance value output CPU memory 9 are connected, but the distance value calculation CPU 6 and the distance value output CPU memory 9 are connected by a signal from the distance value output CPU 8. Then, after a certain time, switch back to the original. The reason why the bus switching circuit 10 has an operation of returning to the original value after a certain period of time is that the distance value output CPU 8 is connected to the distance value calculation CPU 6 and the distance value output CPU memory 9 is connected. Since the distance measurement value output CPU memory 9 storing the execution procedure cannot be accessed,
Bus switching circuit 1
This is because it cannot be sent to 0. Distance measurement value output CPU from distance measurement value calculation CPU 6
8 is connected to a signal line 11 that can send a bus switching timing signal. This is a signal line necessary for performing the operation of the present invention. FIG. 2 shows the distance measurement value calculation CPU 6 in the standard mode.
9 is a flowchart showing a procedure for sending distance measurement value data from the CPU to a distance measurement value output CPU 8. The distance measurement value output CPU 8 outputs a bus switching signal in synchronization with a distance measurement reference signal (a reference signal generated from an internal clock of the laser distance measurement sensor and a pulse signal every 40 μsec). I do. That is, as shown in step S1 of FIG. 2, a bus output signal is output from the distance measurement value output CPU 8, the bus switching circuit 10 receives the bus switching signal in step S2, and in step S3, the bus switching circuit 1
0 switches the bus, connects the distance measurement value calculation CPU 6 and the distance measurement value output memory 9 and opens the distance measurement value output CPU 8 and the distance measurement value output memory 9. Further, at step S4, a distance measurement value calculation CPU
From 6, the distance measurement value data is written to the distance measurement value output memory 9, and at step S 5, the bus switching circuit 10 switches the bus when the specified time has elapsed, and the distance measurement value calculation CPU 6 and the distance measurement value output memory 9 are stored in the memory. Open, distance measurement value output CPU8
And the distance measurement value output CPU memory 9 are connected, and the distance measurement value output CPU 8 reads the distance measurement value data from the distance measurement value output CPU memory 9 in step S6. FIG. 3 is a flowchart showing a procedure for transmitting data from the distance measurement value calculation CPU 6 to the distance measurement value output CPU 8 in the mutual interference prevention mode. That is, as shown in step S11 in FIG. 3, a bus switching timing signal is output from the distance measurement value calculation CPU 6 to the distance measurement value output CPU 8,
In step S12, the distance measurement value output CPU 8 receives the bus switching timing signal. Next, as shown in step S13, a bus switching signal is output from the distance measurement value output CPU 8, the bus switching circuit 10 receives the bus switching signal (step S14), and further, as shown in step S15. , The bus switching circuit 10 switches the bus, and the distance measurement value calculation CPU 6
The distance measurement value output CPU memory 9 is connected, and the distance measurement value output CPU 8 and the distance measurement value output CPU memory 9 are opened. Then, as shown in step S16, the distance measurement value data is written from the distance measurement value calculation CPU 6 to the memory for the distance measurement value output CPU, and when a specified time has elapsed, the bus switching circuit 10 switches the bus, and the distance measurement value is calculated. The calculation CPU 6 and the distance measurement value output memory 9 are opened, and the distance measurement value output CPU 8 and the distance measurement value output memory 9 are connected. Then, in step S18, the distance measurement value output CPU 8
The distance measurement value data is read from the U memory 9. The difference from the standard mode is that the distance measurement value calculation C
The only difference is that a bus switching timing signal is sent from the PU 6 to the distance measurement value output CPU 8. Distance value output CPU 8
Receives the bus switching timing signal and sets a timing to the reference signal immediately after the bus switching timing signal, and outputs the bus switching signal to the bus switching circuit 10. FIG. 4 shows a standard mode in which a distance measurement value calculation CPU 6 stores a distance measurement value output memory 9 for CPU.
Is written based on the reference signal. Since the distance measurement value output CPU 8 outputs a bus switching signal based on the reference signal, FIGS. 4 (a) and 4 (b)
As shown in the above, two hold bus switching timings can be considered. The bus switching circuit 10 determines the distance measurement value CP.
The connection between U6 and the distance measurement value output CPU memory 9 is 80 μsec, which is one cycle of distance measurement (40 seconds per head).
It takes μsec to measure distance and 80μ because there are 2 heads
sec is one cycle of distance measurement. ), The distance measurement values of both heads are transmitted from the distance measurement value calculation CPU 6 to the distance measurement value output CPU 8 at either bus switching timing. FIG. 5 shows the timing at which the distance measurement value calculation CPU 6 writes data in the distance measurement value output CPU memory 9 in the mutual interference prevention mode, which is written based on a reference signal. The distance measurement value calculation CPU 6 issues a bus switching timing signal at the timing shown in FIG. As shown in FIGS. 5B and 5A, the timing of measuring the distance of the first optical head (head1) 2 and outputting the distance measurement value, and measuring the distance of the second optical head (head2) 3 The bus switching timing signal is output at two timings, that is, when the distance is measured and the distance measurement value is output. Bus switching is performed from the reference signal immediately after the bus switching timing signal is output, and the distance measurement value calculation C
The distance measurement value data is transmitted from the PU 6 to the distance measurement value output CPU 8. In the mutual interference prevention mode, it is necessary to wait for the distance measurement until the internal circuits of the optical heads 2 and 3 are stabilized. Therefore, a wait of 40 μsec is made between the distance measurement of the first optical head and the distance measurement of the second optical head. By utilizing this waiting time, distance measurement value data of the optical head opposite to the optical head whose distance has been measured is output. [0033] When transmitted at the timing B in FIG. 5 (a), the distance measurement value of head2 being ranging in A is also adapted to be transmitted by A '. When transmitted at the timing of D in FIG. 5B , the distance measurement value of head 1 measured at C is also transmitted at C ′. This minimizes the time lag between the distance measurement values of the optical heads 2 and 3 (head 1 and head 2). (Since the laser distance measuring sensor of the present invention alternately receives distance measuring information from the two optical heads 2 and 3 and measures distances alternately, measurement of head 1 and head 2 in the case described with reference to FIG. 5 is performed. In the mutual interference prevention mode, the timing at which the bus switching signal from the distance measurement value output CPU 8 is output is set to the standard mode without using the bus switching timing signal from the distance measurement value calculation CPU 6. Similarly, if the distance measurement value output is determined only by the CPU 8 , the bus may be switched at the timing of α in FIGS. 5C and 5D. When the bus is switched at such a timing , the optical head 2 (head ) is used in FIG.
The distance measurement value data of 1) cannot be transmitted from the distance measurement value calculation CPU 6 to the distance measurement value output CPU 8. In order to prevent this, the distance measurement value output CPU 8
Then, a bus switching timing signal is sent to time the bus switching. As described above, in the standard mode and the mutual interference prevention mode, the distance measurement value can be transmitted from the distance measurement value calculation CPU 6 to the distance measurement value output CPU 8 without any trouble by one distance value transmission circuit. . As described above, according to the present invention, the light is projected on the object to be measured, the light reflected by the object to be measured is received, and the center of gravity of the received reflected light is detected. Two optical heads for outputting signals, a position signal processing unit for amplifying the position signal from each of these optical heads and converting the signal into a digital signal by A / D conversion, and a digital signal from the position signal processing unit based on the position <br/> signal, receiving the distance measurement value calculating CPU for calculating a distance value of the distance measurement object, the distance measurement value of the calculated distance measurement target object in the distance measurement value calculating CPU, external It used to store the distance value output CPU for outputting a memory for distance measurement value calculating CPU for storing programs and data of the distance measurement value calculating CPU, programs and data of the distance measurement value output CPU to
The distance measurement value calculation CPU and the distance measurement value output CPU
A distance measurement value output CPU memory including a region to be used, a bus connecting the distance measurement value calculation CPU and the distance measurement value output CPU memory in response to a signal from the distance measurement value output CPU, and a distance measurement value output C;
In a laser ranging sensor having a bus switching circuit for switching a bus connecting a PU and a memory for a ranging value output CPU in opposite phases, a laser ranging sensor includes:
In the case of the distance measurement mode in which the operation is the same and high-speed ranging is possible,
The bus switching circuit connects the distance measurement value calculation CPU and the distance measurement value output memory according to a signal from the distance measurement value output CPU, and the distance measurement value calculation CPU writes data to the distance measurement value output memory. while the bus cutting replacement example circuit switches the bus again, connects the focusing value output memory for CPU measured distance output CPU, the distance measurement value output CPU from the memory for the distance measurement value output CPU is data that needs to read , Two optics
Interfering with each other by alternately projecting heads
In the distance measurement mode that prevents
Outputs bus switching timing signal to distance measurement value output CPU
When this is received by the distance measurement value output CPU, the
Bus disconnection to bus switching circuit with timing of quasi-signal
Output signal, which is received by the bus switching circuit.
Switch the bus and output the distance measurement value CPU and the distance measurement value
Connect the CPU memory and the distance measurement value calculation CPU
After writing data to the output CPU memory,
The switching circuit performs bus switching again, and the distance measurement value output CPU
Memory and the distance measurement value output CPU are connected, and the distance measurement value output
Data required by the ranging value output CPU is read from the U memory.
This is a laser measurement that can measure distances by preventing mutual interference when high-speed ranging is required by two optical heads, and when light from two optical heads interferes with each other. In the distance sensor, the operation of the internal circuits of the two optical heads is the same, and the distance measurement mode (standard mode) that allows high-speed ranging and the two optical heads alternately emit light to interfere with each other. It is possible to select both of the distance measurement modes of the distance measurement mode (mutual interference prevention mode) for preventing the interference from occurring, and to share and simplify the circuit used in each mode. Further, a distance measurement value calculation C requiring high-speed calculation
The distance measurement value data can be reliably transmitted from the distance measurement value calculation CPU to the distance measurement value output CPU without hindering the operation of the PU.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system configuration diagram of an embodiment of the present invention. FIG. 2 is a distance measurement value calculation CPU in a standard mode according to the first embodiment;
5 is a flowchart showing a procedure for sending distance measurement value data from the CPU to a distance measurement value output CPU. FIG. 3 is a flowchart showing a procedure for transmitting distance measurement value data from a distance measurement value calculation CPU to a distance measurement value output CPU in the mutual interference prevention mode in the first embodiment. FIG. 4 is a CPU for calculating a distance measurement value in the standard mode according to the first embodiment;
FIG. 6 is a diagram showing timings for writing distance measurement value data in a memory for a distance measurement value output CPU. FIG. 5 is a diagram showing timings at which a distance measurement value calculation CPU writes distance measurement value data to a distance measurement value output CPU memory in the above-described mutual interference prevention mode. [Description of Signs] 1 Object to be measured 2 Optical head 3 Optical head 4 Switch 5 Position signal processing unit 6 Distance measurement value calculation CPU 7 Memory for distance measurement value calculation CPU 8 Distance measurement value output CPU 9 Distance measurement value output CPU Memory 10 Bus switching circuit 11 Control line 12 Switch 13 Switch

Claims (1)

(57) [Claim 1] Light is projected onto an object to be measured, the reflected light from the object to be measured is received, the position of the center of gravity of the received reflected light is detected, and the position signal is detected. Output two optical heads and these
Amplifies the position signal from the optical head, on the basis the position signal processing unit for digital signal by the A / D converter, a digital signal of position signals from the position signal processing unit, measuring the distance measurement object a distance value calculation CPU for calculating a distance value, receives the distance measurement value of the calculated distance measurement target object in the distance measurement value calculating CPU, the distance measurement value output CPU for outputting to the outside, the distance measurement value calculating CPU program Memory for storing a distance measurement value for storing data and data, and a distance calculation CPU for storing programs and data for a distance measurement value output CPU.
The distance measurement value output CPU memory including the area commonly used by the distance measurement value output CPU and the distance measurement value calculation CPU and the distance measurement value output CPU memory are connected by receiving a signal from the distance measurement value output CPU. Bus, ranging value output CPU, and ranging value output CPU
And a bus switching circuit that switches the bus connecting the memory for the opposite phase,
The operation of the internal circuits of the two optical heads is the same, enabling high-speed ranging.
In the case of a possible distance measurement mode, the bus switching circuit connects the distance measurement value calculation CPU and the memory for the distance measurement value output CPU according to a signal from the distance measurement value output CPU. after writing the data in memory for output CPU, bus-cutting exchange example circuit switches the bus again, connects the memory for the distance measurement value output CPU distance value output CPU, ranging from memory for distance measurement value output CPU While the value output CPU reads necessary data , the two optical heads alternately emit light.
Distance measurement mode to prevent interference
In that case, the distance measurement value calculation CPU switches the bus to the distance measurement value output CPU.
A switching timing signal is output and this is output as a distance measurement value output CP.
When U accepts, the timing of the reference signal immediately after is accepted.
And outputs a bus switching signal to the bus switching circuit.
When the bus switching circuit receives the
Connects distance measurement CPU and memory for distance measurement output CPU
The distance measurement value calculation CPU stores the data in the distance measurement value output CPU memory.
After writing data, the bus switching circuit switches the bus
Is performed again, and the distance measurement value output CPU memory and the distance measurement value output C
Connects PU and outputs distance measurement value from memory for CPU
A laser ranging sensor that reads the data required by a power CPU .