A tension sensor using eddy current principle and its detection method

Abstract

The present invention discloses a tension sensor and a detection method thereof using the eddy current principle. The tension sensor includes: a bracket, a metal spring, a displacement transmission rod, a ceramic column and an eddy current detection circuit; the eddy current detection circuit includes a detection coil; one end of the displacement transmission rod is connected to the ceramic column, and the other end of the displacement transmission rod is connected to the metal spring; one end of the metal spring is fixed to the bracket, and the other end of the metal spring is located above the detection coil, and there is a gap between the metal spring and the detection coil; the ceramic column is used to push the displacement transmission rod according to the tension of the yarn, so that the displacement transmission rod drives the metal spring to deform in the direction close to or away from the detection coil. The above technical solution can effectively characterize the actual tension, and can also improve the anti-interference and detection accuracy of the tension detection.

Description

Technical Field

[0001] The present invention relates to the technical field of tension detection, and in particular to a tension sensor applying the eddy current principle and a detection method thereof. Background Art

[0002] In traditional spinning and weaving processes, yarn tension has always been a key parameter affecting the quality of yarn forming. In yarn tension control systems, yarn tension detection is the most basic and important technology.

[0003] At present, tension sensors at home and abroad are divided into contact type and non-contact type. Contact tension sensor refers to the sensor's force measuring rod directly detecting yarn tension, so it has high detection accuracy and high response sensitivity. It is the mainstream dynamic tension sensor at home and abroad. This type of sensor is divided into strain gauge type and piezoelectric ceramic type. Contact tension sensor has certain advantages in signal sampling method, but it has major defects. For example, strain gauge tension sensor must use organic adhesive to stick the strain gauge to elastic body (such as stainless steel) or polyester diaphragm, which has poor hysteresis and can only use single-piece strain gauge bonding. The output sensitivity is low, which is not conducive to use in high-precision tension control scenarios; and piezoelectric ceramic tension sensor has no wide practical application at home and abroad because of its nonlinear voltage output. Non-contact tension sensor has Hall sensor, which actually detects the yarn speed and converts it into tension information, with low control accuracy and poor anti-interference ability. Contact tension sensor is currently produced by only a few manufacturers abroad, and the price is relatively expensive. Summary of the invention

[0004] The invention provides a tension sensor and a detection method thereof using the eddy current principle, so as to solve the problems of low detection sensitivity, poor anti-interference ability and poor hysteresis of the existing tension sensor.

[0005] According to one aspect of the present invention, there is provided a tension sensor using the eddy current principle, comprising: a bracket, a metal spring, a displacement transmission rod, a ceramic column and an eddy current detection circuit; the eddy current detection circuit comprises a detection coil;

[0006] One end of the displacement transmission rod is connected to the ceramic column, and the other end of the displacement transmission rod is connected to the metal dome; one end of the metal dome is fixed to the bracket, and the other end of the metal dome is located above the detection coil, and there is a gap between the metal dome and the detection coil; the ceramic column is used to push the displacement transmission rod according to the tension of the yarn, so that the displacement transmission rod drives the metal dome to deform in a direction close to or away from the detection coil.

[0007] Optionally, the metal spring is fixed to the bracket by a mortise and tenon structure.

[0008] Optionally, the eddy current detection circuit further includes a microprocessor, a resonant circuit and a signal processing circuit;

[0009] The resonant circuit comprises the detection coil and the resonant capacitor, and the detection coil and the resonant capacitor are connected in parallel;

[0010] The microprocessor is electrically connected to the power supply and the resonant circuit respectively; the microprocessor outputs a PWM signal as an excitation signal source of the resonant circuit under the power supply of the power supply;

[0011] The signal processing circuit is electrically connected to the resonant circuit; the signal processing circuit is used to obtain the resonant signal generated by the resonant circuit and output a DC detection signal.

[0012] Optionally, the signal processing circuit includes a signal amplification module and a rectification module;

[0013] The input end of the signal amplifying module is electrically connected to the resonant circuit, and the output end of the signal amplifying module is electrically connected to the rectifier module; the signal amplifying module is used to amplify the resonant signal generated by the resonant circuit and then output the resonant amplified signal to the rectifier module;

[0014] The rectifying module is used for rectifying the resonant amplified signal and then outputting the DC detection signal.

[0015] Optionally, the microprocessor is also electrically connected to the signal processing circuit and the host computer respectively; the microprocessor is used to collect the DC detection signal and provide feedback to the host computer.

[0016] Optionally, the eddy current sensor further includes:

[0017] A temperature-sensitive resistor, the temperature-sensitive resistor is connected in series with the detection coil;

[0018] Alternatively, a temperature sensor is arranged in the area where the detection coil is located; the microprocessor is also electrically connected to the temperature sensor and the signal processing circuit respectively; the microprocessor is also used to collect the temperature signal of the temperature sensor and the DC detection signal respectively, and compensate the DC detection signal according to the temperature signal.

[0019] According to another aspect of the present invention, a detection method of a tension sensor using the eddy current principle is provided, which is applied to any tension sensor described in any embodiment of the present invention, and the detection method comprises:

[0020] When the ceramic column contacts the yarn, the ceramic column pushes the displacement transmission rod according to the tension of the yarn, so that the displacement transmission rod drives the metal spring to deform in a direction close to or away from the detection coil;

[0021] The detection coil of the eddy current detection circuit generates an electrical signal according to the deformation amount of the metal spring;

[0022] The eddy current detection circuit determines the tension of the yarn according to the electrical signal.

[0023] The technical solution of the embodiment of the present invention is to connect one end of the displacement transmission rod to the ceramic column and the other end to the metal spring. The ceramic column can push the displacement transmission rod under the yarn tension, and the displacement transmission rod can drive the metal spring to deform according to the yarn tension, so that the change of the yarn tension can be transmitted to the metal spring to the greatest extent, so that when the final circuit calculates the tension, it can effectively represent the actual tension. One end of the metal spring is fixed on the bracket, which reduces the displacement of the bracket of the tension sensor during the detection process, avoids the deformation of the metal spring caused by external environmental factors, and improves the anti-interference ability of the tension detection. In addition, the other end of the metal spring is located above the detection coil, and there is a gap between the metal spring and the detection coil. The distance between the metal spring and the detection coil is small, which can make the electrical signal sensed by the eddy current detection circuit have higher sensitivity and higher detection accuracy.

[0024] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic structural diagram of a tension sensor using the eddy current principle provided by an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the structure of an eddy current detection circuit provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the structure of another eddy current detection circuit provided by an embodiment of the present invention;

[0029] Figure 4 A schematic diagram of another eddy current detection circuit provided by an embodiment of the present invention

[0030] Figure 5 A flowchart of a detection method for a tension sensor using the eddy current principle provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] The present invention proposes a tension sensor based on the eddy current principle, which is used to detect the tension of the yarn. Figure 1 The schematic diagram of the structure of a tension sensor using the eddy current principle provided by an embodiment of the present invention. Figure 1 As shown, the tension sensor using the eddy current principle includes a bracket 504 , a metal spring 503 , a displacement transmission rod 502 , a ceramic column 501 and an eddy current detection circuit (not shown in the figure), and the eddy current detection circuit includes a detection coil 505 .

[0034] Continue to refer Figure 1 One end of the displacement transmission rod 502 is connected to the ceramic column 501, and the other end of the displacement transmission rod 502 is connected to the metal spring 503; one end of the metal spring 503 is fixed on the bracket 504, and the other end of the metal spring 503 is located above the detection coil 505, and there is a gap between the metal spring 503 and the detection coil 505.

[0035] Specifically, during the actual tension detection process, the ceramic column 501 is in direct contact with the yarn, and according to the tension of the yarn, the displacement transmission rod 502 is pushed, so that the displacement transmission rod 502 drives the metal spring 503 to deform in the direction close to or away from the detection coil 505. There is a fixed gap between the detection coil 505 and the metal spring 503. When the yarn moves on the ceramic column 501, under the action of the yarn tension, the ceramic column 501 drives the displacement transmission rod 502 to force the metal spring 503 to deform, and the corresponding yarn tension relationship is obtained by detecting the change in the magnetic field of the detection coil at this time.

[0036] For example, using a ceramic column 501 with nanometer-level roughness as the contact surface of the yarn can reduce the detection error caused by the friction between the contact surface of the yarn and the ceramic column 501.

[0037] In the embodiment of the present invention, by connecting one end of the displacement transmission rod to the ceramic column and the other end to the metal spring, the ceramic column can push the displacement transmission rod due to the yarn tension, and the displacement transmission rod can drive the metal spring to deform according to the yarn tension, so that the change of the yarn tension can be transmitted to the metal spring to the greatest extent, so that when the final circuit calculates the tension, the actual tension can be effectively represented; and one end of the metal spring is fixed on the bracket, which reduces the displacement of the bracket of the tension sensor during the detection process, and can avoid the deformation of the metal spring caused by external environmental factors, thereby improving the anti-interference ability of the tension detection; in addition, the other end of the metal spring is located above the detection coil, and there is a gap between the metal spring and the detection coil. The distance between the metal spring and the detection coil is small, which can make the electrical signal sensed by the eddy current detection circuit have higher sensitivity and higher detection accuracy.

[0038] Optionally, the metal spring piece 503 can be fixed to the bracket 504 through a mortise and tenon structure, which can effectively ensure the stability of the connection. To further ensure the connection effect, the metal spring piece 503 can also be fixed to the bracket 504 with screws.

[0039] Optional, Figure 2 The structure diagram of an eddy current detection circuit provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, the eddy current detection circuit includes a microprocessor 100, a resonant circuit 110 and a signal processing circuit 200. The resonant circuit 110 includes a detection coil L1 and a resonant capacitor C1 connected in parallel; the microprocessor 100 is electrically connected to the power supply and the resonant circuit 110 respectively; the microprocessor 100 is used to convert the power supply signal of the power supply into a PWM signal as an excitation signal source of the resonant circuit 110; the signal processing circuit 200 is electrically connected to the resonant circuit 110; the signal processing circuit 200 is used to obtain the resonant signal generated by the resonant circuit 100 and output a DC detection signal.

[0040] Among them, the microprocessor includes but is not limited to devices with computing and / or control functions such as MCU and MPU. Specifically, the tension sensor includes a metal shrapnel, which maintains a certain distance from the detection coil. The metal shrapnel is used to deform in the direction of approaching or moving away from the detection coil L1 under the action of tension; the microprocessor 100 outputs a fixed frequency PWM signal to the resonant circuit 110, and the resonant circuit 110 also generates a resonant signal of the same frequency. When the metal shrapnel approaches or moves away from the detection coil L1, it is affected by the eddy current effect, so that the inductive reactance of the detection coil L1 changes. Correspondingly, the amplitude of the resonant signal generated by the resonant circuit 100 also changes. After being processed by the signal processing circuit 200, a correspondingly changed DC detection signal can be output, and the tension can be detected according to the DC detection signal. It can be understood that the frequency and duty cycle of the PWM signal can be set according to actual needs, thereby achieving different detection accuracies; different resonant frequencies can also be achieved by setting and using different detection coils and resonant capacitors by the microprocessor; the structure of the detection coil can be designed according to needs, such as the number of coil turns, size, thickness, etc., and the detection range and output range of the tension sensor can be adjusted to meet different application scenarios.

[0041] In the embodiment of the present invention, the deformation of the metal spring of the tension sensor is detected by a detection coil, and a resonance signal is generated by connecting the detection coil and the resonance capacitor in parallel to form a resonance circuit. The circuit structure is simple, and the tension can be detected according to the change of the resonance signal caused by the change of the distance between the metal spring and the detection coil, thereby improving the hysteresis of the tension sensor. By electrically connecting the microprocessor to the resonance circuit, the microprocessor can output a PWM signal of a fixed frequency as an excitation signal source of the resonance circuit under the power supply signal of the power supply, so that the resonance circuit can generate a resonance signal of the same frequency. The resonance signal frequency is fixed and is not easily affected by external factors, thereby improving the anti-interference ability of the tension detection. The resonance signal can be converted into a DC detection signal through the signal processing circuit, thereby improving the sensitivity of the tension detection.

[0042] Optional, continue to refer to Figure 2 The signal processing circuit 200 includes a signal amplifying module 210 and a rectifying module 220. The input end 211 of the signal amplifying module 210 is electrically connected to the resonant circuit 110, and the output end 212 of the signal amplifying module 210 is electrically connected to the rectifying module 220. The signal amplifying module 210 is used to amplify the resonant signal generated by the resonant circuit 110 and output the resonant amplified signal to the rectifying module 220; the rectifying module 220 is used to rectify the resonant amplified signal and output a DC detection signal.

[0043] Exemplarily, the deformation of the metal spring is limited, and the change of the resonance signal generated by the resonance circuit 110 is small. The resonance signal can be amplified by the signal amplification module 210. Compared with the resonance signal generated by the resonance circuit 110, the change of the resonance amplified signal after amplification by the signal amplification module 210 is easier to detect; the resonance amplified signal is rectified into a DC detection signal by the rectification module 220, and the change of the resonance amplified signal can be detected more intuitively and simply, so as to facilitate tension detection, thereby improving the sensitivity and hysteresis of the detection.

[0044] Optional, continue to refer to Figure 2 , the microprocessor 100 is electrically connected to the signal processing circuit 200 and the host computer respectively, and the microprocessor 100 is used to collect the DC detection signal and provide feedback to the host computer. Exemplarily, the microprocessor 100 can receive the DC detection signal output by the signal processing circuit 200, and the microprocessor 100 outputs a feedback signal to the host computer according to the DC detection signal. The host computer includes but is not limited to devices such as a display, and can display the tension data according to the feedback signal output by the microprocessor 100.

[0045] Optional, continue to refer to Figure 2 The eddy current detection circuit of the tension sensor also includes: an output circuit 300, and the microprocessor 100 is electrically connected to the host computer through the output circuit 300. The microprocessor 100 is also used to collect DC detection signals and output tension detection signals to the output circuit 300; the output circuit 300 is used to output an output signal that is linearly related to the tension of the metal spring to the host computer according to the tension detection signal.

[0046] Exemplarily, the output circuit 300 can output a digital signal and / or an analog signal according to the tension detection signal, or can output an output signal corresponding to and linearly related to the tension exerted on the metal spring according to the tension detection signal, thereby improving the signal output capability of the eddy current detection circuit of the tension sensor. It is understandable that the signal output by the output circuit 300 can be a current signal, or a voltage signal and / or a digital communication signal, and the output circuit 300 can output an applicable signal according to actual needs to improve the environmental adaptability of the tension sensor, and can expand more application scenarios. For example, the tension sensor and the eddy current detection circuit thereof provided in the embodiment of the present invention can be applied to application scenarios where tension needs to be detected in the fields of drones, robots, and industrial automation.

[0047] Optional, continue to refer to Figure 2The output circuit 300 includes a fourth-stage operational amplifier OP4, a non-inverting input terminal 041 of the fourth-stage operational amplifier OP4 is electrically connected to the microprocessor 100, an inverting input terminal 042 of the fourth-stage operational amplifier OP4 is electrically connected to an output terminal 043 of the fourth-stage operational amplifier OP4, and an output terminal of the fourth-stage operational amplifier OP4 is electrically connected to a host computer. The output voltage of the output circuit 300 can be changed by the fourth-stage operational amplifier OP4, so that the output circuit 300 outputs a voltage signal that is linearly related to the tension, thereby improving the output capacity of the tension sensor.

[0048] Optional, Figure 3 FIG. 1 is a schematic diagram of the structure of another eddy current detection circuit provided by an embodiment of the present invention. Figure 3 As shown, the eddy current detection circuit of the tension sensor also includes a thermistor R0, which is connected in series with the detection coil L1. The resistance of the thermistor R0 changes with temperature, and can reversely compensate for the resistance change of the detection coil L1. Exemplarily, if the temperature rises, the electrical signal of the detection coil L1 affected by the temperature increases, and the resistance of the thermistor R0 will change with the temperature rise, so that the electrical signal of the detection coil L1 decreases, compensating for the temperature change of the detection coil L1, so that the DC detection signal output by the signal processing circuit 200 is not affected by temperature, reducing the temperature drift of the detection result, and improving the temperature adaptability of the tension sensor and its eddy current detection circuit.

[0049] Optional, Figure 4 FIG. 1 is a schematic diagram of the structure of another eddy current detection circuit provided by an embodiment of the present invention. Figure 4 As shown, the eddy current detection circuit of the tension sensor also includes a temperature sensor 400, which is arranged in the area where the detection coil L1 is located; the microprocessor 100 is also electrically connected to the temperature sensor 400 and the signal processing circuit 200 respectively. Among them, the microprocessor 100 is also used to collect the temperature signal and the DC detection signal of the temperature sensor 400 respectively, and compensate the DC detection signal according to the temperature signal. Specifically, the microprocessor 100 directly performs temperature compensation on the DC detection signal according to the temperature signal of the temperature sensor 400, reduces the temperature drift of the detection result, and improves the temperature adaptability of the tension sensor and its eddy current detection circuit.

[0050] Based on the same inventive idea, an embodiment of the present invention provides a detection method for a tension sensor using the eddy current principle. The detection method is applied to the tension sensor using the eddy current principle described in any embodiment of the present invention. Figure 5 A flow chart of a detection method of a tension sensor using the eddy current principle provided by an embodiment of the present invention is shown in FIG. Figure 5 As shown, the detection method includes:

[0051] S110. When the ceramic column contacts the yarn, the ceramic column pushes the displacement transmission rod according to the tension of the yarn, so that the displacement transmission rod drives the metal spring to deform in a direction close to or away from the detection coil.

[0052] S120. The detection coil of the eddy current detection circuit generates an electrical signal according to the deformation of the metal spring.

[0053] S130, the eddy current detection circuit determines the tension of the yarn according to the electrical signal.

[0054] For example, during actual measurement, the yarn is placed on a ceramic column. As the yarn tension increases, the yarn will pass through the ceramic column and the displacement transmission rod to cause the metal spring to gradually move toward the detection coil. Since the relative position of the metal spring and the detection coil changes, an induced electromotive force is generated, causing the electrical signal in the detection coil of the eddy current detection circuit to change accordingly. The eddy current circuit can collect the electrical signal and its change, and calculate the magnitude of the tension.

[0055] It is understandable that after the yarn drives the metal spring to deform, the current yarn tension data can be read in a variety of ways. For example, the current yarn tension data can be directly read by the host computer; the current yarn tension data can also be obtained by simulating / fitting by reading the digital signal and / or analog signal output by the eddy current detection circuit, and no additional processing of the yarn is required in the whole process.

[0056] The detection method of the tension sensor using the eddy current principle provided in the embodiment of the present invention is applied to the tension sensor using the eddy current principle described in any embodiment of the present invention, and has corresponding beneficial effects.

[0057] Since the tension sensor uses many components in the process of tension detection, slightly different relative positions or sizes of the components will lead to different detection results. Before the formal detection, the force information can be calibrated and compensated by the microprocessor to calibrate the relationship between the deformation of the metal spring and the output DC detection signal.

[0058] It should be understood that the various forms of modules shown above can be used, recombined, added or deleted. For example, the modules described in the present invention can be applied to the tension sensor at the same time, or can be applied to the tension sensor in different combinations, as long as the desired results of the technical solution of the present invention can be achieved, and this document is not limited here.

[0059] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A tension sensor using the eddy current principle, used to detect the tension of a yarn, characterized in that: include: A bracket, a metal spring, a displacement transmission rod, a ceramic column and an eddy current detection circuit; the eddy current detection circuit includes a detection coil; One end of the displacement transmission rod is connected to the ceramic column, and the other end of the displacement transmission rod is connected to the metal spring; one end of the metal spring is fixed to the bracket, and the other end of the metal spring is located above the detection coil, and there is a gap between the metal spring and the detection coil; the ceramic column is used to push the displacement transmission rod according to the tension of the yarn, so that the displacement transmission rod drives the metal spring to deform in the direction of approaching or moving away from the detection coil; The ceramic column is a ceramic column with nanometer-level roughness; The eddy current detection circuit also includes a microprocessor, a resonant circuit and a signal processing circuit; The resonant circuit comprises the detection coil and the resonant capacitor, and the detection coil and the resonant capacitor are connected in parallel; The microprocessor is electrically connected to the power supply and the resonant circuit respectively; the microprocessor outputs a PWM signal as an excitation signal source of the resonant circuit under the power supply signal of the power supply; The signal processing circuit is electrically connected to the resonant circuit; the signal processing circuit is used to obtain the resonant signal generated by the resonant circuit and output a DC detection signal.

2. The tension sensor using the eddy current principle according to claim 1, characterized in that: The metal spring sheet is fixed on the bracket through a mortise and tenon structure.

3. The tension sensor using the eddy current principle according to claim 1, characterized in that: The signal processing circuit includes a signal amplification module and a rectification module; The input end of the signal amplifying module is electrically connected to the resonant circuit, and the output end of the signal amplifying module is electrically connected to the rectifier module; the signal amplifying module is used to amplify the resonant signal generated by the resonant circuit and then output the resonant amplified signal to the rectifier module; The rectifying module is used for rectifying the resonant amplified signal and then outputting the DC detection signal.

4. The tension sensor using the eddy current principle according to claim 1, characterized in that: The microprocessor is also electrically connected to the signal processing circuit and the host computer respectively; the microprocessor is used to collect the DC detection signal and feed back to the host computer.

5. The tension sensor using the eddy current principle according to claim 1, characterized in that: The eddy current detection circuit also includes: A temperature-sensitive resistor, the temperature-sensitive resistor is connected in series with the detection coil; Alternatively, a temperature sensor is arranged in the area where the detection coil is located; the microprocessor is also electrically connected to the temperature sensor and the signal processing circuit respectively; the microprocessor is also used to collect the temperature signal of the temperature sensor and the DC detection signal respectively, and compensate the DC detection signal according to the temperature signal.

6. A method for detecting a tension sensor using the eddy current principle, applied to the tension sensor according to any one of claims 1 to 5, characterized in that: The detection method comprises: When the ceramic column contacts the yarn, the ceramic column pushes the displacement transmission rod according to the tension of the yarn, so that the displacement transmission rod drives the metal spring to deform in a direction close to or away from the detection coil; The detection coil of the eddy current detection circuit generates an electrical signal according to the deformation amount of the metal spring; The eddy current detection circuit determines the tension of the yarn according to the electrical signal.

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