CN203133033U - Fruit firmness nondestructive detection device based on laser doppler vibrometry - Google Patents
Fruit firmness nondestructive detection device based on laser doppler vibrometry Download PDFInfo
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- CN203133033U CN203133033U CN 201320092726 CN201320092726U CN203133033U CN 203133033 U CN203133033 U CN 203133033U CN 201320092726 CN201320092726 CN 201320092726 CN 201320092726 U CN201320092726 U CN 201320092726U CN 203133033 U CN203133033 U CN 203133033U
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Abstract
The utility model discloses a fruit firmness nondestructive detection device based on laser doppler vibrometry. The device mainly comprises a vibration control system and a vibration signal acquisition system, wherein the vibration control system comprises a computer, a vibration control module, a power amplifier, a vibration generator, an expansion table and a charge type acceleration sensor, and the vibration signal acquisition system comprises a laser doppler vibrometer module, an ICP (inductively coupled plasma) acceleration sensor, a data acquisition card and a tripod. A fruit firmness nondestructive detection method based on laser doppler vibrometry comprises the following steps of: collecting representative fruits to form a modeling sample set; determining the sample quality; collecting vibration signals; processing the vibration signals; determining the firmness normal value; establishing and verifying a firmness forecasting model; and carrying out filtering, calculus, FFT (fast Fourier transformation) and amplitude-frequency response calculation on output signals from a laser doppler vibrometer controller and the ICP acceleration sensor by using the self-provided signal analysis software of the laser doppler vibrometer module. The device and the method are free from the influence of ambient noise, do not destroy the free vibration of fruits, have good adaptability and realize the nondestructive detection on fruit firmness.
Description
Technical field
The utility model relates to the cannot-harm-detection device of fruit hardness, relates in particular to a kind of fruit hardness the cannot-harm-detection device based on the laser-Doppler vibration measuring.
Background technology
China have the laudatory title of " world's fruit kingdom ", the fruit of almost all kinds has to be produced and the output height, but because the detection stage equipment falls behind, fruit is still not enough in competitiveness in the international market, the outlet rate is lower, and there is the ripe softening problem of rotting that reaches in fruit in adopting the back transporting procedures.The hardness of fruit also claims consolidation, refers to the power of pulp compressive resistance, can be used as an important indicator judging degree of ripeness and quality.Detect the hardness of fruit exactly, for determine suitable harvest time, adopt that the back is preserved, best edible phase of assessment and grading etc. are all significant.
Traditional fruit hardness detection method mainly is sampling, chooses several check points at the Chi Daochu of sample usually, removes the peel at check point then, being pressed into the inner certain distance of fruit with matter structure instrument or sclerometer records, this is a kind of destructive detection, and the check rate is low, wastes time and energy and causes a large amount of wastes.The lossless detection method of at present relevant fruit hardness mainly is the Acoustic detection method, also has part Study to mention near infrared spectrum detection method and hyperspectral space scattering curve method etc.The interference that Acoustic detection method signal is subjected to neighbourhood noise easily causes accuracy of detection not high, and the mode that some use is knocked also can cause certain damage to fruit; Near infrared technology is relevant with its chemical substance, and the hardness of fruit is main relevant with its physical arrangement, thereby the near infrared detection result is not very good, and check point need be avoided defective locations during for the defective sample of fruit surface; And high spectral technique is subjected to such environmental effects such as light source very big, the testing conditions harshness.
Laser-Doppler vibration measuring technology (Laser Doppler Vibrometry (LDV) technology) be one for detection of the technology of object mechanical vibration performance.Measurement for the fruit mechanical vibration performance can be divided into dual mode: contact and contactless.Traditional measuring method need be attached to the object under test surface to acceleration transducer, utilize the measurement of correlation of the signal realization " Jia Su Du – Su Du – displacement " of its output, the mounting means of this contact can destroy original vibrational state, even can't use in many occasions, therefore limited its range of application.And laser-Doppler vibration measuring technology is as a kind of contactless measurement, light harvesting electromechanics is one, not influenced by neighbourhood noise, have the precision height, dynamic response is fast, measurement range is big, anti-electromagnetic interference (EMI), transverse vibration is disturbed advantages such as insensitive, also very effective to the vibration that detected amplitude is small, its characteristics have satisfied the needs of fruit vibration survey.In the fruit of differing texture, the transmission of vibrational energy is inevitable different, therefore theoretically, can detect the mechanical vibration performance of fruit in order to the relation between foundation and the hardness by utilizing this technology.
Summary of the invention
At the problem that exists in the above-mentioned background technology, the purpose of this utility model is to provide a kind of fruit hardness the cannot-harm-detection device based on the laser-Doppler vibration measuring.Obtain the fruit vibration signal by this device, and this signal is handled, obtain characteristic frequency, set up rigidity prediction model, thereby realize the Non-Destructive Testing to fruit hardness.
The technical solution adopted in the utility model is:
Involving vibrations control system and vibration signal acquisition system, wherein:
1) vibration control system: comprise computing machine, vibration control module, power amplifier, vibration generator, expansion platform and charge type acceleration transducer; The vibration control module is installed in the PCI slot of computing machine, the expansion platform is rigidly connected on the vibration generator, the charge type acceleration transducer is fixed on the expansion platform with mounting screw, and the output terminal of vibration control module is connected with the vibration generator through power amplifier;
2) vibration signal acquisition system: comprise laser-Doppler vibration measuring module, ICP acceleration transducer, data collecting card and tripod; Wherein laser-Doppler vibration measuring module is made up of laser acquisition head and laser-Doppler vibration measuring controller; The laser acquisition head erect is placed on the tripod downwards, laser beam is incident upon place, fruit upper surface summit perpendicular to the expansion table top, the vertical range on amasthenic lens and fruit upper surface summit is greater than the minimum operating distance of laser acquisition head, the ICP acceleration transducer is fixed on the expansion platform with mounting screw, the two-way input end of data collecting card is connected with the output terminal of laser-Doppler vibration measuring controller and ICP acceleration transducer respectively, and the output terminal of data collecting card is connected with computing machine;
The signal analysis software that laser-Doppler vibration measuring module carries carries out filtering, integration, FFT, asks amplitude-frequency response the output signal of laser-Doppler vibration measuring controller and ICP acceleration transducer.
A kind of fruit rigidity nondestructive testing method based on the laser-Doppler vibration measuring:
Step (1) is gathered representative fruit and is formed the modeling sample collection;
The mensuration of step (2) sample quality: the quality that takes by weighing each sample with electronic balance;
Step (3) vibration signals: sample is put in the center of vibration generator expansion platform and it is imposed the pumping signal of frequency change, measure the vibration velocity signal at place, sample upper surface summit with laser-Doppler vibration measuring module, measure the vibration acceleration signal of expansion table top with the ICP acceleration transducer, the two-way vibration signal that obtains is through the data collecting card collection and deliver to the computing machine preservation, and sample frequency is 5120 Hz;
The processing of step (4) vibration signal: the two-way vibration signal that collects is carried out filtering, integration, Fast Fourier Transform (FFT) processing, ask amplitude-frequency response again, and extract characteristic frequency;
The mensuration of step (5) hardness standard value: at maximum weighted/lifting surface area (N/cm of omnipotent each sample of mechanical test aircraft measurements
2), as the hardness standard value;
Foundation and the checking of step (6) rigidity prediction model: sample is divided into correction group and checking group, and the ratio of dividing correction group and checking group is 3:1, adopts linear regression method that the correction group sample is set up model between mechanical vibration performance and its hardness; And based on the checking group resulting forecast model is verified, the predicted value of comparative sample hardness and standard value, and according to the demand in the actual production, model is optimized.
In the described step (3), computing machine is by vibration control module output oscillation control signal, excited vibration generator work after power amplifier amplifies, pumping signal is the sine sweep signal of 5-2000 Hz, playing vibration frequency is 5 Hz, increases with linear forms, and sweep rate is 600 Hz/min, 5-32 Hz amplitude constant is 0.5 mm, and 32-2000 Hz acceleration is constant to be 1 g; Fruit is placed on the center of the expansion platform on the vibration generator, the laser acquisition head erect is placed on the tripod downwards, laser beam is incident upon place, fruit upper surface summit perpendicular to the expansion table top, regulate the amasthenic lens of laser acquisition head, make laser beam focus on place, fruit upper surface summit through lens; The laser that reflects from vibration fruit upper surface summit is received by the laser acquisition head, output voltage signal after laser-Doppler vibration measuring controller is handled, again by the data collecting card collection, and be transferred on the computing machine and preserve, finally obtain the vibration velocity signal at place, fruit upper surface summit; The ICP acceleration transducer is fixed on the vibration generator expansion platform, obtains the vibration acceleration signal of expansion table top and by the data collecting card collection, and is transferred on the computing machine and preserves.
In the described step (4), at first be the two-way vibration signal elimination high frequency interference noise of low-pass filter to collecting of 2 kHz by cutoff frequency, the ICP acceleration transducer being recorded vibration acceleration signal then is rate signal through an Integral Transformation, as input signal, the vibration velocity signal that laser-Doppler vibration measuring module records is as output signal, respectively input, output signal are carried out Fast Fourier Transform (FFT), ask amplitude-frequency response, and from amplitude-frequency response, extract characteristic frequency.
The utility model is compared with background technology, and the beneficial effect that has is:
1, Non-Destructive Testing.Utilize laser-Doppler vibration measuring technology, only need fruit is placed on the expansion platform, detect excitation with acceleration transducer and laser-Doppler vibration measuring module and get final product with response signal, Zhen Dong mode can not cause damage to fruit simultaneously, the original state of maintenance fruit that can be intact.
2, do not destroy testee free vibration.Laser-Doppler vibration measuring technology can not destroy the original free vibration state of fruit, and dynamic response is fast, makes vibration signal accurately and reliably as a kind of non-contact measuring technology.
3, adaptability is good.The test environment aspect does not have specific (special) requirements, is not subjected to influence of environmental noise, does not need a special test space yet.
Description of drawings
Fig. 1 is method flow diagram of the present utility model.
Fig. 2 is apparatus structure synoptic diagram of the present utility model.
Among the figure: 1, computing machine; 2, vibration control module; 3, power amplifier; 4, vibration generator; 5, expansion platform; 6, charge type acceleration transducer; 7, ICP acceleration transducer; 8, fruit; 9, laser acquisition head; 10, laser-Doppler vibration measuring controller; 11, data collecting card.
Fig. 3 is the engineering drawing of the utility model expansion platform.
Fig. 4 is the linear regression model (LRM) figure of elasticity coefficient and the hardness of correction group papaya among the utility model embodiment.
Fig. 5 is the scatter diagram of checking group papaya Hardness Prediction value and standard value among the utility model embodiment.
Embodiment
The utility model is described in further detail below in conjunction with drawings and Examples.
As Fig. 2, shown in Figure 3, device involving vibrations control system of the present utility model and vibration signal acquisition system, wherein:
1) vibration control system: comprise computing machine 1, vibration control module 2(such as Amber multifunction vibration controller), power amplifier 3(such as PA-1200), vibration generator 4(such as ES-05), expansion platform 5 and charge type acceleration transducer 6(DL-24100); Vibration control module 2 is installed in the PCI slot of computing machine 1, expansion platform 5 is by being rigidly connected to 6 uniform screws of circumference array form on the vibration generator 4, charge type acceleration transducer 6 usefulness M5 mounting screws are fixed on the expansion platform 5, and the output terminal of vibration control module 2 is connected with vibration generator 4 through power amplifier 3;
2) vibration signal acquisition system: comprise laser-Doppler vibration measuring module (as LV-S01), ICP acceleration transducer 7(such as LC0159), data collecting card 11(such as NI USB-4431) and tripod; Wherein laser-Doppler vibration measuring module is made up of laser acquisition 9 and laser-Doppler vibration measuring controller 10; Laser acquisition 9 is placed on the tripod straight down, laser beam is incident upon place, fruit 8 upper surface summits perpendicular to the expansion table top, the vertical range on amasthenic lens and fruit 8 upper surface summits is greater than laser acquisition 9 a minimum operating distance, ICP acceleration transducer 7 usefulness M5 mounting screws are fixed on the expansion platform 5, the two-way input end of data collecting card 11 is connected with the output terminal of laser-Doppler vibration measuring controller 10 and ICP acceleration transducer 7 respectively, and the output terminal of data collecting card 11 is connected with computing machine 1;
The signal analysis software that laser-Doppler vibration measuring module carries carries out filtering, integration, FFT, asks amplitude-frequency response the output signal of laser-Doppler vibration measuring controller 10 and ICP acceleration transducer 7.
The said apparatus course of work:
Computing machine sends the sine sweep signal to power amplifier by the vibration control module, this signal is the work of excited vibration generator after amplifying, be placed on the fruit vibration together thereupon on the expansion platform, the charge type acceleration transducer feeds back to vibration control module formation closed-loop control with the actual vibration acceleration signal that records simultaneously; The fruit vibration velocity signal that laser-Doppler vibration measuring module records is delivered to the passage 2 of data collecting card, and the expansion platform vibration acceleration signal that the ICP acceleration transducer records is delivered to the passage 1 of data collecting card; By data collecting card the two-way vibration signal that collects is delivered on the computing machine at last, and handled by the signal analysis software that laser-Doppler vibration measuring module carries.
Described expansion platform uses screw to be rigidly connected with the vibration generator, realizes the steady function of placing fruit and driving its vibration in the utility model, and expansion platform material is magnalium; In the middle of the expansion platform diameter being arranged is 60 mm, and the degree of depth is the pit of 3 mm, and pit bottom is posted one deck dry sanding paper, and skew and rotation take place when preventing from making the fruit vibration.
The detection of the utility model fruit hardness has versatility, be example with papaya, introduce the implementation process that the utility model detects papaya hardness, other fruit can be with reference to the method for this embodiment, set up corresponding rigidity prediction model, can carry out Non-Destructive Testing to the hardness of different fruit.
Embodiment: based on the papaya hardness Non-Destructive Testing of laser-Doppler vibration measuring, carry out according to step as shown in Figure 1:
1, the papaya sample is gathered:
Gather 100 of papaya in market, select representative papaya as far as possible and form the modeling sample collection, make the sample durometer level big as far as possible.
2, the mensuration of sample quality: be the quality that the electronic balance of 0.01 g takes by weighing each sample with precision.
3, vibration signals:
As shown in Figure 2, papaya (being fruit 8) is placed on the expansion platform 5, computing machine 1 is by vibration control module 2 output oscillation control signals, excited vibration generator 4 work after power amplifier 3 amplifies, control signal is the sine sweep vibration signal of 5-2000 Hz, playing vibration frequency is 5 Hz, increase with linear forms, sweep rate is 600 Hz/min, and 5-32 Hz amplitude constant is 0.5 mm, and 32-2000 Hz acceleration is constant to be 1 g.Papaya is placed on the center of expansion platform 5 above the vibration generator 4, laser acquisition 9 is placed on the tripod straight down, laser beam is incident upon place, papaya upper surface summit perpendicular to expansion platform 5 faces, regulate the amasthenic lens of laser acquisition 9, make laser beam focus on place, papaya upper surface summit through lens.Received by laser acquisition 9 from the laser that reflects of papaya upper surface summit of vibration, output voltage signal after laser-Doppler vibration measuring controller 10 is handled is collected the vibration velocity signal of papaya again by data collecting card 11; ICP acceleration transducer 7 is fixed on the expansion platform 5 that vibrates above the generator 4, and acquisition is expanded the vibration acceleration signal of platform 5 and gathered by data collecting card 11.The two-way vibration signal is delivered to computing machine 1 and is preserved after data collecting card 11 is gathered.
4, the mensuration of hardness standard value:
Choose equidistant 4 point measurement hardness at papaya carpopodium to maximum gauge place between carpopodium, with the hardness number of its mean value as this sample.The hardness measurement method is: at select location one deck thin skin of pruning, test surfaces is smooth, the peel thickness of pruning is unsuitable excessive, the least possible pulp that undermines, the area of peeling is slightly larger than the omnipotent mechanical test compressing head area that uses, and sample is put on the omnipotent mechanical test machine then, and pressure head is pressed into the speed of 1 mm/s, be pressed into 10 mm and stop, the hardness of this point is maximum weighted/lifting surface area (N/cm
2), the used pressure head diameter of present embodiment is 6 mm.The durometer level of the papaya that records in the experiment is 1.02-10.71 N/cm
2
5, the processing of vibration signal:
Be that the low-pass filter of 2 kHz is to signal elimination high frequency interference noise by cutoff frequency at first, the ICP acceleration transducer being recorded vibration acceleration signal then is rate signal through an Integral Transformation, as input signal, the vibration velocity signal that laser-Doppler vibration measuring module records is as output signal, respectively input, output signal are carried out Fast Fourier Transform (FFT) (FFT), ask amplitude-frequency response, and from amplitude-frequency response, extract characteristic frequency.
6, the foundation of rigidity prediction model and checking:
For 100 papaya samples, at first reject 6 exceptional values according to the standardized residual of hardness number, 94 remaining samples are divided correction group and checking group according to the proportionate relationship of 3:1.Divide the two-part every indicator-specific statistics value in back and see Table 1.
The hardness number statistical value of table 1 correction group and checking group sample
| Sample set | Sample size | Durometer level (N/cm 2） | Hardness average (N/cm 2） | Standard deviation (N/cm 2） |
| Correction group | 71 | 1.02-10.71 | 4.86 | 2.25 |
| The checking group | 23 | 2.20-9.44 | 5.16 | 1.93 |
Then, calculate the elasticity coefficient of each sample according to following formula
EI:
In the formula:
f 2 Be second resonant frequency,
mBe the papaya quality.
Adopt one-variable linear regression, set up elasticity coefficient based on correction group
EIWith the linear regression model (LRM) of hardness, i.e. rigidity prediction model, the coefficient of determination R of model
2=0.631, as shown in Figure 4.Recycling checking group sample is verified the rigidity prediction model of setting up.Predicted value and standard value are compared, the result as shown in Figure 5, as can be seen, the correlation coefficient r of predicted value and standard value=0.724 in the checking group, prediction standard error SEP=1.055 shows that the forecast model of setting up can dope the hardness of papaya more exactly.
From above-described embodiment as can be seen, the utility model is based on the vibratory response of laser-Doppler vibration measuring technology for detection papaya under certain excited vibration signal effect, from the amplitude-frequency response of input/output signal, calculate the elasticity coefficient of papaya behind extraction second resonant frequency, utilize linear regression to set up the papaya rigidity prediction model, thereby realize the Non-Destructive Testing to papaya hardness.
Above-mentioned embodiment is used for the utility model of explaining; rather than the utility model limited; in the protection domain of spirit of the present utility model and claim, any modification and change to the utility model is made all fall into protection domain of the present utility model.
Claims (1)
1. fruit hardness the cannot-harm-detection device based on the laser-Doppler vibration measuring is characterized in that: this device involving vibrations control system and vibration signal acquisition system; Wherein:
1) vibration control system: comprise computing machine (1), vibration control module (2), power amplifier (3), vibration generator (4), expansion platform (5) and charge type acceleration transducer (6); Vibration control module (2) is installed in the PCI slot of computing machine (1), expansion platform (5) is rigidly connected on the vibration generator (4), charge type acceleration transducer (6) is screwed on expansion platform (5), and the output terminal of vibration control module (2) is connected with vibration generator (4) through power amplifier (3);
2) vibration signal acquisition system: comprise laser-Doppler vibration measuring module, ICP acceleration transducer (7), data collecting card (11) and tripod; Wherein laser-Doppler vibration measuring module is made up of laser acquisition head (9) and laser-Doppler vibration measuring controller (10); Laser acquisition head (9) is placed on the tripod straight down, laser beam is incident upon place, fruit (8) upper surface summit perpendicular to the expansion table top, the vertical range on amasthenic lens and fruit (8) upper surface summit is greater than the minimum operating distance of laser acquisition head (9), ICP acceleration transducer (7) is fixed on the expansion platform (5) with mounting screw, the two-way input end of data collecting card (11) is connected with the output terminal of laser-Doppler vibration measuring controller (10) with ICP acceleration transducer (7) respectively, and the output terminal of data collecting card (11) is connected with computing machine (1); The signal analysis software that laser-Doppler vibration measuring module carries carries out filtering, integration, FFT, asks amplitude-frequency response the output signal of laser-Doppler vibration measuring controller (10) and ICP acceleration transducer (7).
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105021699A (en) * | 2015-07-16 | 2015-11-04 | 无锡市崇安区科技创业服务中心 | Bridge pier crack nondestructive detection device |
| CN105403625A (en) * | 2015-12-05 | 2016-03-16 | 浙江大学 | Portable fruit maturity detection device |
| CN105675720A (en) * | 2016-04-13 | 2016-06-15 | 浙江大学 | Fruit firmness information online collecting system and method |
| CN106198730A (en) * | 2016-07-17 | 2016-12-07 | 江南大学 | A kind of convergence testing agency automatically |
| CN107543801A (en) * | 2017-08-25 | 2018-01-05 | 天津商业大学 | Hardness Prediction method after mango impact injury based on EO-1 hyperion |
| CN110501065A (en) * | 2019-07-24 | 2019-11-26 | 南京农业大学 | Hybrid rice based on collision characteristic splits clever Seed inspection method |
| CN111855800A (en) * | 2020-07-17 | 2020-10-30 | 西南科技大学 | Method for rapidly and nondestructively measuring shelf life or optimal edible period of fruit by acoustic vibration |
| CN114184678A (en) * | 2021-12-08 | 2022-03-15 | 石河子大学 | Online nondestructive testing device and method for maturity of bergamot pears by laser Doppler vibration measurement method |
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2013
- 2013-02-28 CN CN 201320092726 patent/CN203133033U/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105021699A (en) * | 2015-07-16 | 2015-11-04 | 无锡市崇安区科技创业服务中心 | Bridge pier crack nondestructive detection device |
| CN105403625A (en) * | 2015-12-05 | 2016-03-16 | 浙江大学 | Portable fruit maturity detection device |
| CN105675720A (en) * | 2016-04-13 | 2016-06-15 | 浙江大学 | Fruit firmness information online collecting system and method |
| CN106198730A (en) * | 2016-07-17 | 2016-12-07 | 江南大学 | A kind of convergence testing agency automatically |
| CN107543801A (en) * | 2017-08-25 | 2018-01-05 | 天津商业大学 | Hardness Prediction method after mango impact injury based on EO-1 hyperion |
| CN110501065A (en) * | 2019-07-24 | 2019-11-26 | 南京农业大学 | Hybrid rice based on collision characteristic splits clever Seed inspection method |
| CN111855800A (en) * | 2020-07-17 | 2020-10-30 | 西南科技大学 | Method for rapidly and nondestructively measuring shelf life or optimal edible period of fruit by acoustic vibration |
| CN111855800B (en) * | 2020-07-17 | 2022-04-01 | 西南科技大学 | Method for rapidly and nondestructively measuring shelf life or optimal edible period of fruit by acoustic vibration |
| CN114184678A (en) * | 2021-12-08 | 2022-03-15 | 石河子大学 | Online nondestructive testing device and method for maturity of bergamot pears by laser Doppler vibration measurement method |
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Granted publication date: 20130814 |