TWI302598B - Measurement system - Google Patents

Description

139. The invention relates to a measuring system, and more particularly to a measuring system for measuring the distance using a laser. [Prior Art] The range accuracy of the laser phase ranging system can reach the quaternary level. The laser phase ranging system can measure distances from tens of meters to several hundred meters without the aid of an auxiliary object (for example: 稜鏡). With an auxiliary object (prism), the distance measurement capability can reach several hundred meters or even several kilometers. It can be seen that the laser phase ranging system is a powerful ranging tool that can be applied in a multi-quantity measurement market (for example, engineering construction, transportation system, real estate, home DIY, industrial automation, etc.). In addition, the laser phase ranging system is made into a palm-sized product and is powered by a common inspective battery' so that it can be used in everyday life. Φ It can be seen that ranging in the laser phase mode is a fairly mature technology. The main method is to perform signal modulation on the laser light and calculate the actual distance by using the amount of phase information passed by the laser light. The following descriptions will be given for different laser phase ranging techniques. Related single laser light emitters and dual laser light receiving device technologies are known in the first prior art. The laser light emitted by the laser light emitter is split by a beam splitter, wherein the light beam of the main light path is emitted and then reflected on the target = and then reflected to the main receiving device, and the light beam of the auxiliary light path is received by the sub-reflection through the system. The distance received by the device is obtained by comparing the two receiving signals received by the main receiving device and the secondary receiving device 0757-A21591 TWF (N2); E0106036; ALEXL) N η 1302598. However, this technique has the disadvantage that the phase characteristics of the main receiving device and the sub-receiving device cannot be completely identical, except that the main receiving device and the sub-receiving device cannot maintain their stability in addition to the temperature change and the long-term use time. The bias voltages of the primary receiving device and the secondary receiving device are also different. All of the above problems will affect the accuracy of the measured phase information. Related secondary laser light emitters and single laser zero light receiver technology are known in the second prior art, which have the disadvantage that the uniformity of the two laser emitters cannot be achieved. Related three-beam laser emitters and dual-laser light-receiving device technologies are known in the third prior art, which solve the problems of the aforementioned techniques mainly by means of offsetting. The light beams emitted by each illuminator are simultaneously received by the two receiving devices, so that each group of frequency points has four measurements, and then the combination of different frequency points can increase the number of measurements. However, this method not only increases the complexity of the system operation, is difficult to adjust and test, but also can not effectively reduce the cost, and the bias voltage of the receiving device changes during different measurement processes. The offset cannot be offset. Furthermore, it is known in the fourth prior art that the related shutter technique mainly uses a single laser light emitter and a single laser light receiving device to adjust the light path through the switch of the shutter, thereby not generating the device in the aforementioned technology. Inconsistency issues. However, since the reflection is performed by means of a shutter, the instability caused when the shutter is turned off causes the reflected light to be unstable. In addition, due to the use of fiber optic reception, the invisible is also greatly increased to 0757-A21591TWF (N2); E0106036; ALEXLIN 8 1302598, to improve the difficulty of system assembly and debugging. SUMMARY OF THE INVENTION In view of the above, the present invention provides a measurement system for performing distance measurement on an object positioned at a predetermined location. The measurement system includes a signal generation module, a first processing unit, a second processing unit, a third processing unit, a switching unit and a fourth processing unit. The Φ signal generating module generates an initial signal having a modulation frequency, a comparison signal having a local oscillation frequency, and a reference signal having an output frequency. The first processing unit converts the initial signal into a primary signal and a primary signal with respect to a reference position, wherein the primary signal forms a first reflected primary signal via reflection of the object. The second processing unit converts the first reflected main signal into a first processed signal. The third processing unit converts the secondary signal into a second processing signal. The receiving device receives the first processing signal from the second processing unit and the second processing signal from the third processing unit. The switching unit 10 is switchable between a first position and a second position, and when the switching unit is in the first position, the switching unit blocks the first processing signal from running to the receiving device, and when the switching unit is in the second position, switching The unit blocks the second processing signal from running to the receiving device. The fourth processing unit is configured to compare the comparison signal of the signal generation module with the first processing signal of the second processing unit received by the receiving device, respectively, under the comparison signal of the signal generation module. The comparison signal between the signal generation module and the second processing signal of the third processing unit received by the receiving device is processed. Compared with the reference signal, when the switching unit is in the first position, the ratio is 0757-A21591 TWF(N2); E0106036; ALEXL!N 9 1302598 is mixed with the second processing signal to generate a first phase. One of the first predetermined signals, when the switching unit is in the second position, the second comparison signal is generated by the comparison signal and the first processing signal. The above and other objects, features, and advantages of the present invention will become more apparent and understood. A schematic diagram of the inventive measurement system K. The measuring system K is used to measure the distance of an object T located at a predetermined position z0. The measurement system K includes a signal generation module R, a first processing unit U1, a second processing unit U2, a third processing unit U3, a receiving device 4r, a switching unit W, a fourth processing unit U4, and a The first filter module 83, a second filter module 84 and a phase detector module 9. The signal generating module R includes a frequency source (divide, PLL) 1, a first filter 21, a second filter 22, and a driving unit 3. In the present embodiment, the first filter 21 and the second filter 22 are LC filters, in particular, LC resonant band pass filters and waves; the driving unit 3 is a laser light driving circuit. The frequency generator 1 generates a first modulation signal ΚΠ, a second modulation signal c01 and a reference signal r01. The first modulation signal i01 is converted into a sine wave form signal iO1' by the square wave under the filtering of the first filter 21, and 0757-A21591 TWF(N2); E0106036; ALEXLIN 10 1302598 signal i〇l' The initial signal il is generated via the driving of the drive unit 3. The second modulation signal c01 generates a comparison signal cl via the second filter 22. The initial signal il has a modulation frequency Π, the comparison signal cl has a local oscillation frequency f2, and the reference signal r01 has an output frequency fl-f2. Subsequently, the initial signal il is transmitted to the first processing unit U1. The first processing unit U1 comprises a transmitting device 4e and a first switching device 5. The initial signal il from the signal generating module R is coupled to the transmitting device φ 4e for modulation and output. The first conversion device 5 includes a first light guide 50, a first optical element 51 and a second optical element 52, wherein the first optical element 51 and the second optical element 52 are disposed inside the first light guide 50. . In the present embodiment, the transmitting device 4e is a laser light emitter, the first optical element 51 is a collimating lens, and the second optical element 52 is a beam splitter. When the transmitting device 4e transmits the initial signal il to the first optical component 51, a first light beam L1 is formed, which is transmitted to the second optical component 52 under the guidance of the first light guiding device 50, and The first light beam L1 is divided into a main signal L1 penetrating through the second optical element 52 and a sub-signal Lib reflected on the surface of the second optical element 52 by the light splitting function of the second optical element 52. The main signal Lla is emitted outside the system and toward the object T, and a first reflection main signal Lla' is formed under the reflection of the surface of the object T. Subsequently, the first reflected main signal Lla' is transmitted to the second processing unit U2. The secondary signal Lib is routed to the third processing unit U3 inside the system. The second processing unit U2 comprises a second conversion device 6. The second conversion device 0757-A21591 TWF(N2); E0106036; the ALEXLIN 11 1302598 device 6 includes a second light pipe 60 and a third optical element 61. The first reflected main signal Lla' is focused by the third optical element 61 to form a first processed signal Lla'01. The third processing unit U3 includes a third light pipe 70 and a fourth optical element 71, and the secondary signal Lib is totally reflected by the fourth optical element 71, and then guided out of the third processing unit U3 by the third light pipe 60. In the present embodiment, the fourth optical element 71 is an optical high-reflection element, in particular, an optical element in which the wavelength band of the light beam of the sub-signal Lib reaches a high reflectance. The switching unit W is disposed on one side of the second light pipe 60 of the second processing unit U2 or the third light pipe 70 of the third processing unit U3, and the switching unit W is at a first position pi and a second position p2 Switch between. In this embodiment, the switching unit W is a shutter or a visor. The receiving device 4r can receive the first processing signal Lla'01 from the second processing unit U2 and the second processing signal φ Llb'01 from the third processing unit U3, respectively. The switching unit W is disposed between the receiving device 4r and the second light pipe 60 of the second processing unit U2 and the third light pipe 70 of the third processing unit U3. In this embodiment, the receiving device 4r is a laser receiver. When the switching unit W is in the first position pi, the switching unit W can prevent the first processing signal Lla'01 from running to the receiving device 4r. When the switching unit W is in the second position p2, the switching unit W can block the second processing signal Llb. '01 runs to the receiving device 4r. The fourth processing unit U4 includes a mixer 81 and an amplifier 82. The mixer 81 respectively mixes the comparison signal cl with the first processed signal Lla'01 by 0757-A21591TWF(N2); E0106036; ALEXL!N 12 1302598 frequency to generate the first fixed frequency signal L2a; or the comparison signal cl and the first The second processing signal Llb'O1 is mixed to generate a second fixed frequency signal L2b. The first and second fixed frequency signals L2a and L2b amplify the signals via the amplifier 82 to form a first predetermined signal L3a and a second predetermined signal L3b, respectively. In this embodiment, the first predetermined signal L3a and the second predetermined signal L3b are respectively an intermediate frequency signal having a frequency Π -f2. When the switching unit W is in the second position p2, the comparison signal cl is mixed with the first φ signal Lla, 01 to generate a first predetermined signal L3a having a first phase value φ ;; when the switching unit W is at the first When the position pi is mixed, the comparison signal cl is mixed with the second processing signal Llb'01 to generate a second predetermined signal L3b having a second phase value φ2, wherein the first phase value φ 1 of the first predetermined signal L3a is One half of the difference between the second phase value φ2 of the second predetermined signal L3b, φ2-φ1/2, represents the distance φ2-φ1/2 between the predetermined position ζ0 and the reference position ζ1. The first filter module 84 is disposed between the phase detector module 9 and the frequency generator 1 and the second filter module 83 is disposed between the phase detector module 9 and the fourth processing unit U4. The phase discrimination module 9 is configured to compare the reference signal r01 passing through the second filter module 84 with the first predetermined signal L3a or the second predetermined signal L3b passing through the first filter module 83. In this embodiment, the first chopper module 83 and the second filter module 84 are narrowband filter circuits. Fig. 2 is a circuit diagram showing a frequency generator 1 in the signal generating module r of Fig. 1. The frequency generator 1 comprises a voltage control X-tal oscillator 101, a crystal oscillator (〇scillat〇r)1〇2, 0757-A21591TWF(N2); E0106036; ALEXLIN 13 1302598 knife frequency mode. The group 103 and a phase locked loop 104 〇 crystal oscillator 102 have an output frequency of fl, thereby serving as a modulation frequency of the system. The output frequency of the voltage controlled crystal oscillator 101 is f2, thereby serving as the local oscillation frequency. In order to ensure the stable frequency difference between the output frequency fl and the local oscillator frequency f2, the frequency division of the output frequency ΠN and the local frequency f2 are phase-locked by the phase-locked loop 1〇4, and then phase-locked. The output is controlled for the voltage controlled crystal oscillator 101. The choice of frequency is calculated by _ and needs to satisfy fl/N=f2/M=fl-f2 to ensure a stable output for the final mixing. In this embodiment, the frequency dividing module 103 can be a specific frequency-divided chip or can be variable digitally divided by the CPLD, and the phase-locked loop 1〇4 can be a phase-detecting circuit or a dedicated phase-locked chip (for example: 4046 phase-locked wafer). In a preferred embodiment, the emitting device 4e can employ a semiconductor light emitting diode 'Laser Diode (LD); the receiving device 4r can use a photovoltaic element, such as a photodiode (PD) ) or Avalanche Photo Diode (APD), and can be mixed inside the snow-cracking photodiode, which eliminates the need for dedicated mixers, reducing cost and simplifying the circuit. The phase-detecting module 9 usually uses an analog-to-digital converter to collect signals, and performs data calculation processing via an MCU or a DSP. It is worth noting that since the main signal Lla and the sub-signal Lib share the same component, and the processed main signal Lla and the sub-signal Lib are compared with the same reference signal r01, in addition to achieving a good offset effect. In addition, measurement deviations caused by various aspects such as environment, temperature, and usage time can be eliminated. In addition, the switching unit W operates by blocking the beam with 0757-A21591 TWF(N2); E0106036; ALEXL!N 14 1302598, without affecting the measurement accuracy of the system. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention, and the present invention can be modified and retouched without departing from the spirit and scope of the present invention. The scope of protection is subject to the definition of the scope of the patent application attached.

0757-A21591TWF(N2); E0106036; ALEXLIN 15 1302598 [Simplified Schematic] FIG. 1 is a schematic diagram showing a measurement system (κ) of the present invention; and FIG. 2 is a diagram showing a signal generation module (R) of FIG. A circuit diagram of a frequency generator (1).

[Description of Main Components] 1 to frequency generator 101 to voltage controlled crystal oscillator 102 to crystal oscillator 103 to frequency dividing module 104 to phase locked loop 21 to first filter 22 to second filter 3 to driving unit 4e~transmitting device 4r~receiving device 5 to first converting device 50 to first light pipe 51 to first optical element 52 to second optical element 6 to second converting device 60 to second light guide 61 to third optical element Cl~ comparison signal fl~ modulation frequency fl-f2~ output frequency £2~ local oscillator frequency i01~first modulation signal iOl'~signal il~ initial signal K~measurement system L1~first beam

Lla ~ main signal

Lla'~ first reflection main signal

Lla’01~first processing signal

Lib~second signal L2a, L2b~ fixed frequency signal pi~first position p2~second position R~signal generation module 0757-A21591TWF(N2); E0106036;ALEXLIN 16 1302598 70~third light pipe 71~fourth optical Element 81 to mixer 82 to amplifier 83 to first filter, wave module 84 to second filter module 9 to phase detector module c01 to second modulation signal r01 to reference signal T to object U1 to first processing Unit U2 to second processing unit U3 to third processing unit U4 to fourth processing unit W to switching unit z0 to a predetermined position

0757-A21591 TWF(N2); E0106036; ALEXLIN

Claims (1)

1302598 X. Patent application scope: 1. A measurement system for measuring distance of an object located at a predetermined position, the measurement system comprising: a signal generation module for generating an initial signal; The processing unit divides the initial signal into a primary signal and a primary signal, wherein the primary signal is used to send to a reference position; and a second processing unit is configured to receive one of the first $processing signals reflected by the reference position a third processing unit receiving a second processing signal from the one of the signals; a receiving device respectively receiving the first processing signal or the second processing signal; a switching unit configured to control the receiving device to receive the The first processing signal or the second processing signal; and a fourth processing unit respectively receiving the first processing signal and the second processing signal to generate a first phase value and a second phase value, and by using a ratio Calculating the distance between the measurement system and the reference position for the first phase value and the second phase value. 2. The measurement system of claim 1, wherein the signal generation module further generates a reference signal having a local frequency and a reference signal having an output frequency. 3. The measurement system of claim 2, wherein the reference signal is mixed with the first processed signal and the second processed signal to generate the first phase value and a second phase value. 0 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 a second filter, the frequency generator generates a first modulation signal and a second 碉=signal 'where the first modulo is generated via the first filter: an initial signal, the second modulation signal is The second filter generates the comparison signal. 5. The measurement system of claim 4, wherein the signal generating module further comprises an optical driving unit for driving the initial signal through the first filter. 6. The measurement system of claim 4, wherein the first filter and the second filter are LC filters. The measuring system of claim 1, wherein the first processing unit comprises a transmitting device and a first converting device, and the transmitting I transmits the initial signal to the first converting device to form The main signal and the signal. The measuring system of claim 7, wherein the first converting means comprises a first optical component, and the initial signal forms the main signal and the secondary signal via the first optical component. The measurement system of claim 7, wherein the first conversion device comprises a first light guide, a first lens and a first optical element, and the initial signal is sequentially passed through the first lens. The first light guide and the first optical component form the main signal and the secondary signal. The measuring system of claim 1, wherein the second processing unit comprises a second converting device, the second converting device is 0757-A21591 TWF(N2); E0106036; ALEXLIN 19 1302598 A reflected main signal is converted into the first processed signal. 11. The measurement system of claim 10, wherein the second conversion device comprises a second light guide and a second lens, the first reflective main signal sequentially passing through the second lens and the second The first processing signal is formed by the guiding of the two light pipes. 12. The measuring system of claim 1, wherein the third processing unit comprises a third light pipe, the second signal is formed by the guiding of the third φ light pipe to form the second processing signal. . 13. The measurement system of claim 1, wherein the third processing unit comprises a third light pipe and a second optical element, the second signal is sequentially scattered via the second optical element, The second processing signal is formed after the guiding of the second light guide. 14. The measurement system of claim 1, wherein the fourth processing unit includes a mixer for performing a comparison between the comparison signal and the first processing signal and the second processing signal, respectively. Processing, and generating φ a first predetermined signal and a second predetermined signal. 15. The measurement system of claim 1, wherein the fourth processing unit includes a mixer and an amplifier for respectively comparing the first signal to the first processing signal and the second processing signal Processing is performed to generate a certain frequency signal, and processed by the amplifier to form a first predetermined signal and a second predetermined signal. 16. The measurement system of claim 1, further comprising a phase detection module for comparing the reference signal with the first predetermined signal or the second predetermined signal. 17. The measuring system of claim 1, further comprising a first filtering module, a second filtering module and a phase detecting module, wherein the measuring system of claim 1 is further included The phase detector module is configured to compare the reference signal with the first predetermined signal or the second predetermined signal. 18. The measurement system of claim 1, wherein the switching unit is a shading element. 19. The measurement system of claim 1, wherein the receiving device further comprises an avalanche photodiode. 0757-A21591TWF(N2); E0106036; ALEXLIN 21