Disclosure of Invention
The invention aims to provide a device and a method for automatically adjusting the position of a probe of a thermometer, so that the distance and the angle between the probe of an infrared radiation thermometer and the surface of a measured object can be automatically adjusted, and the optimal distance and the optimal angle between the probe of the infrared radiation thermometer and the surface of the measured object can be determined in a short time.
In order to achieve the purpose, the invention provides the following scheme:
an automatic thermo detector probe position adjustment device, the device comprising: the device comprises a standard thermocouple, an infrared radiation thermometer, a comparator, a microprocessor, a motor and a control platform;
the comparator is respectively connected with the standard thermocouple and the infrared radiation thermometer; the comparator is used for comparing the actual temperature value of the hot junction of the standard thermocouple with the measured temperature value of the hot junction of the standard thermocouple measured by the infrared radiation thermometer and sending the comparison result to the microprocessor;
the motor is respectively connected with the microprocessor and the control platform; the microprocessor controls the movement of the motor according to the comparison result;
a probe of the infrared radiation thermometer is arranged on the control platform; the control platform is driven by the motor to move.
Optionally, the method further includes:
the laser beam emitted by the fiber laser irradiates the hot junction of the standard thermocouple;
and the first analog-to-digital converter is connected between the standard thermocouple and the comparator and is used for converting the information output by the standard thermocouple into an actual temperature value of a hot junction of the standard thermocouple.
Optionally, the method further includes:
and the second analog-to-digital converter is connected between the infrared radiation thermometer and the comparator and used for converting the information output by the infrared radiation thermometer into a measurement temperature value of a standard thermocouple hot junction measured by the infrared radiation thermometer.
Optionally, the method further includes:
and the digital display meter is connected between the standard thermocouple and the first analog-to-digital converter and is used for amplifying and displaying the information output by the standard thermocouple.
A method of automatically adjusting the position of a thermometer probe, the method comprising:
acquiring an actual temperature value of a hot junction of a standard thermocouple;
acquiring a measurement temperature value of a hot junction of a standard thermocouple measured by an infrared radiation thermometer;
comparing the actual temperature value with the measured temperature value to obtain a temperature deviation value;
and automatically adjusting the position of the probe of the infrared radiation thermometer according to the temperature deviation amount until the temperature deviation amount is 0, and determining the position of the probe as the optimal position.
Optionally, the acquiring an actual temperature value of the hot junction of the standard thermocouple specifically includes:
controlling a laser beam output by a fiber laser, enabling the laser beam to irradiate a hot junction of a standard thermocouple, and enabling the standard thermocouple to output thermoelectric force which has a determined functional relation with the temperature of the hot junction;
and converting the thermoelectric potential into an actual temperature value of a hot junction of a standard thermocouple.
Optionally, the obtaining of the measured temperature value of the hot junction of the standard thermocouple measured by the infrared radiation thermometer specifically includes:
controlling a probe of the infrared radiation thermometer to measure the hot junction temperature of the standard thermocouple, and outputting a voltage signal which has a determined functional relationship with the hot junction temperature;
and converting the voltage signal into a measured temperature value of a hot junction of a standard thermocouple.
Optionally, the automatically adjusting the position of the probe of the infrared radiation thermometer according to the temperature deviation amount until the temperature deviation amount is 0, and determining that the position of the probe is the optimal position specifically includes:
calculating a control quantity for controlling the motor according to the sign and the magnitude of the temperature deviation quantity;
controlling the rotor rotation of the motor according to the control amount; the motor is connected with a control platform, and the probe is mounted on the control platform;
and acquiring the temperature deviation amount in real time, and controlling the rotor of the motor to stop rotating until the temperature deviation amount is 0, wherein the position of the probe is the optimal position.
Optionally, the calculating the control quantity for controlling the motor according to the sign and the magnitude of the temperature deviation amount specifically includes: calculated using a fuzzy PID control algorithm.
An automatic thermometer probe position adjustment system, the system comprising:
the actual temperature value acquisition unit is used for acquiring the actual temperature value of the hot junction of the standard thermocouple;
the device comprises a measured temperature value acquisition unit, a temperature measurement unit and a control unit, wherein the measured temperature value acquisition unit is used for acquiring a measured temperature value of a hot junction of a standard thermocouple measured by an infrared radiation thermometer;
the comparison unit is used for comparing the actual temperature value with the measured temperature value to obtain a temperature deviation value;
and the optimal position determining unit is used for automatically adjusting the position of the probe of the infrared radiation thermometer according to the temperature deviation amount until the temperature deviation amount is 0, and determining that the position of the probe is the optimal position.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention uses a comparison method and a closed-loop control system, controls the servo motor to drag the movement and the angle adjustment of the control platform by continuously comparing the deviation amount of the temperature value output by the digital display meter connected with the standard thermocouple and the temperature value output by the infrared radiation thermometer, and can avoid the deviation brought to the measurement of the surface temperature of the measured object by determining the placement position and the angle of the probe of the infrared radiation thermometer only according to empirical data or the results obtained by a certain number of tests.
The automatic regulating device for the probe position of the thermometer does not need manual intervention, and only automatically regulates the position and the angle of the probe according to the deviation amount of the temperature value output by the digital display meter connected with the standard thermocouple and the temperature value output by the infrared radiation thermometer, so that the artificial errors caused by manually measuring the distance between the probe and the surface of the measured object and regulating the probe angle can be avoided.
The automatic probe position adjusting device for the infrared radiation thermometer, which is designed by the invention, can complete the determination of the position and the angle of the probe within 45 seconds, greatly reduce the measurement error, reduce the workload and the preparation time of the test, and improve the test efficiency. The application of the automatic adjusting system can also be expanded to other fields using infrared radiation thermometers.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a device and a method for automatically adjusting the position of a probe of a thermometer, so that the distance and the angle between the probe 10 of an infrared radiation thermometer 11 and the surface of a measured object can be automatically adjusted, and the optimal distance and the optimal angle between the probe 10 of the infrared radiation thermometer 11 and the surface of the measured object can be determined in a short time.
The automatic probe 10 position adjustment device of the infrared radiation thermometer 11 is applied to a laser heating constant temperature closed-loop control system for calibrating the relationship between the hot junction temperature of a thermocouple and the output thermoelectric force thereof. The relationship between the output thermal potential of a standard thermocouple and its hot junction temperature is known, whereas the relationship between the output thermal potential of a calibrated thermocouple and its hot junction temperature requires calibration testing to be obtained.
In order to make the hot junction temperature of the calibrated thermocouple 13 constant, a laser heating constant temperature closed-loop control system needs to be designed, and the control system is shown in fig. 1.
The calibrated thermocouple 13 is affected by the environmental heat dissipation and the self heat conduction mechanism during the laser heating process, and the surface temperature of the calibrated thermocouple will fluctuate greatly. In order to keep the hot junction temperature of the calibrated thermocouple 13 constant, the power of the laser output by the fiber laser 1 needs to be adjusted in real time according to the change of the hot junction temperature of the calibrated thermocouple 13. In fig. 1, a fiber laser 1 is a controlled object, and the power of the output laser can be linearly adjusted by a direct current voltage signal of 0 to 10V. The temperature of the hot junction of the calibrated thermocouple 13 is a controlled quantity, and the function of the whole control system is to keep the difference between the temperature of the hot junction of the calibrated thermocouple 13 and a given temperature within an allowable range. The infrared radiation thermometer 11 is a feedback loop measurement link for measuring the temperature of the hot junction of the calibrated thermocouple 13 and feeding back the temperature data to the input of the system for comparison with the given temperature data. The controller of the laser heating constant-temperature closed-loop control system is a PXIe-5515 high-precision data acquisition card, data signals which are output by an infrared radiation thermometer 11 on a system feedback loop and represent temperature are acquired through a designed program, then the data signals are compared with given temperature data, the difference value of the data signals is input into an adaptive PID control algorithm to obtain a control quantity, finally, the PXIe-5515 high-precision data acquisition card outputs a corresponding direct-current control voltage signal of 0-10V to the optical fiber laser 1 according to the control quantity, and control over the output laser energy of the optical fiber laser 1 is achieved.
The important link of the whole laser heating constant temperature closed-loop control system is whether the temperature measurement result of the infrared radiation thermometer 11 to the hot junction of the calibrated thermocouple 13 is accurate, and the measurement result of the infrared radiation thermometer 11 is related to the placing position and the angle of the probe 10 of the infrared radiation thermometer, so that the design of a system capable of automatically adjusting the position and the angle of the probe of the infrared radiation thermometer is necessary.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
The first embodiment is as follows:
referring to fig. 2, an embodiment of the present invention provides an apparatus for automatically adjusting a probe position of a thermometer, including: the device comprises a standard thermocouple 2, an infrared radiation thermometer 11, a comparator 5, a microprocessor 6, a motor 8 and a control platform 9;
wherein, the comparator 5 is respectively connected with the standard thermocouple 2 and the infrared radiation thermometer 11; the comparator 5 is used for comparing the actual temperature value of the hot junction of the standard thermocouple 2 with the measured temperature value of the hot junction of the standard thermocouple 2 measured by the infrared radiation thermometer 11 and sending the comparison result to the microprocessor 6;
the motor 8 is respectively connected with the microprocessor 6 and the control platform 9; the microprocessor 6 controls the movement of the motor 8 according to the comparison result; the motor 8 is connected to the control platform 9 and can drive the control platform 9 to move.
A probe 10 of an infrared radiation thermometer 11 is arranged on the control platform 9; the control platform 9 is driven by the motor 8 to move; the control platform 9 is a control platform 9 with six degrees of freedom, and can realize the movements of front and back, left and right, pitching and the like under the driving of the motor 8.
In addition, the automatic position adjusting device for the thermometer probe 10 provided by the embodiment of the present invention further includes: a fibre laser 1, a first analogue to digital converter 4 and a second analogue to digital converter 12.
The first analog-to-digital converter 4 is connected between the standard thermocouple 2 and the comparator 5, and the second analog-to-digital converter 12 is connected between the infrared radiation thermometer 11 and the comparator 5.
As an optional implementation manner, the device for automatically adjusting the position of the probe 10 of the thermometer provided by the embodiment of the present invention further includes a digital display meter 3 and a digital-to-analog converter 7, the digital display meter 3 is connected between the standard thermocouple 2 and the first analog-to-digital converter 4, and the digital display meter 3 is configured to amplify and display information output by the standard thermocouple 2; the digital-to-analog converter 7 is respectively connected with the microprocessor 6 and the motor 8, and a control signal of the microprocessor 6 is converted into an analog quantity signal through the digital-to-analog converter 7, so that the rotor of the motor 8 is controlled to rotate.
The specific using process is that the laser beam output by the fiber laser 1 irradiates on the hot junction of the standard thermocouple 2, the standard thermocouple 2 outputs thermoelectric force which has a determined functional relation with the hot junction temperature, the thermoelectric force is amplified through the digital display meter 3 to form a first voltage signal, and the first voltage signal is converted into a digital quantity signal which represents the actual hot junction temperature of the standard thermocouple 2 through the first analog-to-digital converter 4. The above function is a linear function, which can be expressed as U ═ KT, where K is a known proportionality coefficient, and the temperature T can be calculated from the thermoelectric force U. The basic principle of thermocouple temperature measurement is that the closed loop is constituteed to the material conductor of two kinds of different compositions, when there is temperature gradient at both ends, will have the electric current to pass through in the return circuit, just has the electromotive force between the both ends this moment, promptly: thermal electromotive force, which is the so-called Seebeck effect (Seebeck effect).
The infrared radiation thermometer 11 comprises a probe 10 and measures the hot junction temperature of the standard thermocouple 2 through the probe 10 to output a second voltage signal in a determined functional relationship with the hot junction temperature of the standard thermocouple 2, which second voltage signal is converted by a second digital-to-analog converter into a digital quantity signal representing the measured temperature of the hot junction of the thermocouple 2. The above function is a linear function, which can be expressed as U '═ K' T ', where K' is a known proportionality coefficient, and the temperature T 'can be calculated from the thermoelectric voltage U'. The linear functional relationship can be found in the specification of the infrared radiation thermometer used.
The comparator 5 receives the digital quantity signal representing the actual hot junction temperature of the standard thermocouple 2 and the digital quantity signal representing the measured hot junction temperature of the standard thermocouple 2, converts the digital quantity signals into the corresponding actual hot junction temperature value of the standard thermocouple 2 and the measured hot junction temperature value of the standard thermocouple 2, compares the deviation amount of the two temperature values, and outputs the temperature deviation amount to the microprocessor 6.
The microprocessor 6 calculates the control quantity for controlling the motor 8 according to the sign and the magnitude of the temperature deviation, the control quantity is a digital quantity signal, the control quantity is converted into a corresponding analog quantity signal through the digital-to-analog converter 7, and the analog quantity signal is output to a driving control system of the motor 8, so that the rotor of the motor 8 can be driven to rotate, and the control platform 9 provided with the probe 10 of the infrared radiation thermometer 11 is dragged to move. In fig. 2, when the temperature value output by the digital display meter 3 connected to the standard thermocouple 2 is not equal to the temperature value output by the infrared radiation thermometer 11, the motor 8 will continuously adjust the position and angle of the control platform 9. And the adjustment is stopped only if the temperature value output by the digital display meter 3 connected with the standard thermocouple 2 is equal to the temperature value output by the infrared radiation thermometer 11. At this time, the position and angle of the probe 10 are the optimal installation positions, and the temperature of the hot junction of the standard thermocouple 2 measured by the infrared radiation thermometer 11 is the actual temperature. At this time, the power supply to the servo motor 8 can be turned off.
It should be noted that the motors 8 mentioned in the embodiments of the present invention are all servo motors.
As an alternative embodiment, the microprocessor 6 may calculate the amount of control over the motor 8 using a fuzzy PID control algorithm, specifically,
and according to the sign and the magnitude of the temperature deviation, a control algorithm for calculating a control quantity for controlling the motor 8 is realized, and a fuzzy PID control algorithm is adopted. (PID is the English initial of proportional-integral-derivative)
And 3 parameters of the PID are modified on line by using a fuzzy control rule so as to adapt to the requirements of the changed temperature deviation e and the temperature deviation change rate ec on PID parameter self-adaption. An automatic adjusting system for the position of a probe 10 of an infrared radiation thermometer 11 based on a fuzzy PID control algorithm is shown in FIG. 3.
The principle of the fuzzy PID control algorithm is as follows: firstly, determining a parameter KP、KI、KDAnd the fuzzy relation between the fuzzy relation and e and ec continuously detects e and ec, and modifies 3 parameters controlled by PID on line according to a fuzzy rule so as to meet the requirements of different e and ec on control parameters.
Parameter KP、KI、KDThe functional relationship between e and ec is:
in the formula, KP0、KI0、KD0Initial values for 3 parameters; Δ KP、ΔKI、ΔKDCorrection values for 3 parameters; e is the temperature deviation; ec is a temperature deviation change rate.
After fuzzification and fuzzy reasoning are carried out on system input e and ec, increment delta K of 3 parameters is obtainedP、ΔKI、ΔKDThe incremental value plus its initial value can be used to obtain the actual parameters of PID control.
PID control parameter KP、KI、KDThe self-adaptive principle of (2) can be realized by the following steps:
to reduce the system response time, KPThe value of (A) should be large; at the same time, a smaller K should be takenDSo as to avoid the differential supersaturation phenomenon caused by the instant increase of e; get K at the same timeI=0。
Secondly, when the | e | and | ec | are of medium size, in order to reduce the overshoot of the system and ensure the response speed of the system, a smaller K is requiredPModerate value of KIAnd KDThe value is obtained.
③ when | e | is small, K should be increased to ensure the stability of the systemPAnd KIThe value of K should be chosen appropriately to avoid system oscillationDThe value is obtained. The principle is as follows: when | ec | is small, KDUsually taken as medium size; when | ec | is large, KDSmaller values should be taken.
The automatic regulating device for the probe position of the thermometer provided by the embodiment of the invention uses a comparison method and a closed-loop control system, and controls the motor 8 to drag the movement and the angle regulation of the control platform 9 by continuously comparing the deviation amount of the temperature value output by the digital display 3 connected with the standard thermocouple 2 and the temperature value output by the infrared radiation thermometer 11, so that the deviation of the measurement of the surface temperature of the measured object caused by the placement position and the angle of the probe 10 of the infrared radiation thermometer 11 determined only according to empirical data or the results obtained by a certain number of tests can be avoided; the position and the angle of the probe 10 are automatically adjusted only according to the deviation amount of the temperature value output by the digital display meter 3 connected with the standard thermocouple 2 and the temperature value output by the infrared radiation thermometer 11 without manual intervention, so that the artificial errors caused by manually measuring the distance between the probe 10 and the surface of a measured object and adjusting the angle of the probe 10 can be avoided; and the position and the angle of the probe 10 can be determined within 45 seconds, so that the measurement error is greatly reduced, the workload and the preparation time of the test are reduced, and the test efficiency is improved. The application of the automatic adjusting system can also be expanded to other fields using infrared radiation thermometers.
Example two:
referring to fig. 4, an embodiment of the present invention provides a method for automatically adjusting a probe position of a thermometer, including:
s1, acquiring an actual temperature value of a hot junction of the standard thermocouple; the method specifically comprises the following steps:
s21, controlling the laser beam output by the fiber laser, enabling the laser beam to irradiate the hot junction of the standard thermocouple, and enabling the standard thermocouple to output thermoelectric force which has a determined functional relation with the temperature of the hot junction; .
S22, converting the thermoelectric potential into an actual temperature value of a hot junction of a standard thermocouple; amplifying the thermoelectric potential to form a first voltage signal, then converting the first voltage signal into a digital quantity signal representing the actual temperature of the hot junction of the standard thermocouple, and finally converting the digital quantity signal representing the actual temperature of the hot junction of the standard thermocouple into the actual temperature value of the hot junction of the standard thermocouple.
S2, obtaining a measurement temperature value of a hot junction of a standard thermocouple measured by an infrared radiation thermometer; the method specifically comprises the following steps:
s21, controlling a probe of the infrared radiation thermometer to measure the hot junction temperature of the standard thermocouple, and outputting a voltage signal which has a determined functional relationship with the hot junction temperature, wherein the voltage signal is a second voltage signal;
and S22, converting the voltage signal into a measured temperature value of a hot junction of a standard thermocouple.
And converting the second voltage signal into a digital quantity signal representing the measurement temperature of the hot junction of the standard thermocouple, and converting the digital quantity signal into the measurement temperature value of the hot junction of the standard thermocouple.
And S3, comparing the actual temperature value with the measured temperature value to obtain a temperature deviation value.
S4, automatically adjusting the position of the probe of the infrared radiation thermometer according to the temperature deviation amount until the temperature deviation amount is 0, and determining that the position of the probe is the optimal position; the method specifically comprises the following steps:
s41, calculating a control quantity for controlling the motor according to the sign and the magnitude of the temperature deviation quantity;
and calculating the control quantity for controlling the motor according to the sign and the size of the temperature deviation quantity by using a fuzzy PID control algorithm, wherein the specific calculation process is the same as that recorded in the first embodiment, and the detailed description is omitted here.
S42, controlling the rotor rotation of the motor according to the control quantity; the motor is connected with a control platform, and the probe is mounted on the control platform;
the control quantity is a digital quantity signal, is converted into a corresponding analog quantity signal, and then is output to a drive control system of the motor, so that a rotor of the motor can be driven to rotate, and a control platform provided with an infrared radiation thermometer probe is dragged to move, so that the probe is driven to move.
S43, acquiring the temperature deviation in real time, and controlling the rotor of the motor to stop rotating until the temperature deviation is 0, wherein the position of the probe is the optimal position;
when the temperature deviation is not 0, the motor can continuously adjust the position and the angle of the control platform. The adjustment is stopped only when the temperature deviation amount is 0. At the moment, the position and the angle of the probe are the optimal installation positions, and the temperature of the hot junction of the standard thermocouple measured by the infrared radiation thermometer is the actual temperature. At this time, the power supply of the servo motor can be turned off.
The embodiment of the present invention further provides an automatic adjusting system for a probe position of a temperature measuring instrument, as shown in fig. 5, the system includes:
an actual temperature value acquisition unit M1 for acquiring an actual temperature value of the hot junction of the standard thermocouple;
a measured temperature value obtaining unit M2, configured to obtain a measured temperature value of a hot junction of a standard thermocouple measured by an infrared radiation thermometer;
a comparing unit M3, configured to compare the actual temperature value with the measured temperature value to obtain a temperature deviation amount;
and the optimal position determining unit M4 is used for automatically adjusting the position of the probe of the infrared radiation thermometer according to the temperature deviation amount until the temperature deviation amount is 0, and determining that the position of the probe is the optimal position.
The automatic regulating method for the probe position of the thermometer provided by the embodiment of the invention can automatically regulate the distance and the angle between the probe of the infrared radiation thermometer and the surface of the measured object according to the comparison method and the closed-loop control system, does not need manual intervention, and can complete the determination of the probe position and the angle within 45 seconds, thereby greatly reducing the measurement error, simultaneously reducing the test workload and the preparation time, and improving the test efficiency.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.