Capacitive proximity sensor and temperature drift compensation method thereof

Abstract

The invention discloses a capacitive proximity sensor and a temperature drift compensation method of the capacitive proximity sensor, and the sensor comprises an oscillation detection module which comprises a sensor electrode and is used for outputting an oscillation signal according to the capacitance change of the sensor electrode and converting the oscillation signal into a first electric signal; the temperature detection module is used for detecting the environment temperature at the current moment and outputting a second electric signal; the digital potentiometer is connected with the oscillation detection module and is used for adjusting the first electric signal output by the oscillation detection module by adjusting the tap position; and the main control module is used for controlling the digital potentiometer to adjust the tap according to the second electric signal and outputting a detection result according to the first electric signal. The integrated temperature detection module is used for detecting the environment temperature, the tap position of the digital potentiometer is adjusted to achieve dynamic adjustment of the first electric signal, real-time compensation of the environment temperature change is achieved, and the detection precision and the environment adaptability of the sensor are remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a capacitive proximity sensor and a temperature drift compensation method for the capacitive proximity sensor. Background Art

[0002] Capacitive proximity sensors are widely used in industrial control, consumer electronics and other fields, but their detection distance is easily affected by changes in ambient temperature. To solve the temperature drift problem, traditional capacitive proximity sensors mainly use two methods: one is to use materials with low temperature coefficients to manufacture sensors to reduce the direct impact of temperature on capacitance; the other is to collect a large amount of data to calculate a compensation parameter to compensate through software.

[0003] However, the above schemes have significant defects. The material optimization method is limited by physical properties, the compensation effect is limited, and there are still performance differences between different batches of sensors; the software compensation method requires parameter calibration for individual sensors, and the compensation effect depends on individual sensor parameters, and consistency is difficult to guarantee. Summary of the invention

[0004] In view of the above problems, the present application provides a capacitive proximity sensor and a temperature drift compensation method of the capacitive proximity sensor to solve the above technical problems.

[0005] In a first aspect, the present application provides a capacitive proximity sensor, comprising: an oscillation detection module, comprising a sensor electrode, for outputting an oscillation signal according to a change in capacitance of the sensor electrode, and converting the oscillation signal into a first electrical signal; A temperature detection module, used to detect the current ambient temperature and output a second electrical signal; A digital potentiometer, connected to the oscillation detection module, and used to adjust the first electrical signal output by the oscillation detection module by adjusting the tap position; The main control module is used to control the digital potentiometer to adjust the tap according to the second electrical signal, and output the detection result according to the first electrical signal.

[0006] In a second aspect, the present application provides a temperature drift compensation method for a capacitive proximity sensor, which is applied to the capacitive proximity sensor as described in the first aspect, and the method includes a pre-calibration stage and a real-time compensation stage; The pre-calibration stage includes: Obtaining analog-to-digital conversion values ​​of at least one capacitive proximity sensor sampled at a same preset detection distance in multiple preset temperature ranges; Adjusting the tap position of the digital potentiometer of the capacitive proximity sensor to calibrate the analog-to-digital conversion value of the capacitive proximity sensor to a preset target analog-to-digital conversion value in each of the preset temperature ranges; Acquiring an adjustment parameter of the digital potentiometer, and generating a mapping relationship between the preset temperature range and the adjustment parameter of the digital potentiometer; The real-time compensation stage includes: Obtain the current ambient temperature and determine the preset temperature range to which the ambient temperature belongs; The tap of the digital potentiometer is adjusted according to a mapping relationship between a preset temperature interval to which the ambient temperature belongs and an adjustment parameter of the digital potentiometer, so as to calibrate the analog-to-digital conversion value obtained by sampling the capacitive proximity sensor based on the preset detection distance to the target analog-to-digital conversion value.

[0007] The present application provides a capacitive proximity sensor and a method for compensating for temperature drift of a capacitive proximity sensor. The method establishes a mapping relationship between a preset temperature range and a digital potentiometer adjustment parameter through a pre-calibration stage. In the real-time compensation stage, the potentiometer tap is adjusted according to the current ambient temperature to dynamically calibrate the sensor's analog-to-digital conversion value. Specifically, the pre-calibration stage generates standardized compensation parameters by calibrating the sensor output at different temperatures; the real-time compensation stage quickly matches the corresponding parameters based on the temperature range without relying on complex algorithms or individual sensor data collection. The present application effectively improves the detection consistency of capacitive proximity sensors in a wide temperature environment through standardized calibration procedures and dynamic parameter matching, reduces the workload and cost of individual calibration, and solves the problem of limited material optimization effects and software compensation requiring a large number of individual calibrations in traditional solutions.

[0008] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 A module schematic diagram of a capacitive proximity sensor provided in an embodiment of the present application is shown.

[0011] Figure 2 Another module schematic diagram of a capacitive proximity sensor provided in an embodiment of the present application is shown.

[0012] Figure 3 A flow chart of a pre-calibration phase of a temperature drift compensation method for a capacitive proximity sensor provided in an embodiment of the present application is shown.

[0013] Figure 4A flow chart of the real-time compensation phase of the temperature drift compensation method for a capacitive proximity sensor provided in an embodiment of the present application is shown.

[0014] Figure 5 Another flow chart of the pre-calibration stage of the temperature drift compensation method of the capacitive proximity sensor provided in an embodiment of the present application is shown.

[0015] Figure 6 Another flow chart of the pre-calibration stage of the temperature drift compensation method of the capacitive proximity sensor provided in an embodiment of the present application is shown.

[0016] Figure 7 Another flow chart of the pre-calibration stage of the temperature drift compensation method of the capacitive proximity sensor provided in an embodiment of the present application is shown.

[0017] Figure 8 Another flow chart of the real-time compensation stage of the temperature drift compensation method of the capacitive proximity sensor provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0019] In the embodiments of the present application, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0020] Moreover, the terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0021] In addition, the "plurality" in the embodiments of the present application refers to two or more than two. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A, B and C can be included.

[0022] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0023] The present application embodiment provides a capacitive proximity sensor, Figure 1 A module schematic diagram of a capacitive proximity sensor provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the capacitive proximity sensor includes: The oscillation detection module includes a sensor electrode, which is used to output an oscillation signal according to the capacitance change of the sensor electrode and convert the oscillation signal into a first electrical signal representing the sensor detection result.

[0024] The temperature detection module is used to detect the current ambient temperature, convert the temperature information into an electrical signal, and output a second electrical signal representing the ambient temperature.

[0025] The digital potentiometer is connected to the oscillation detection module and is used to adjust the first electrical signal output by the oscillation detection module by adjusting the tap position (ie, resistance value). Optionally, the tap of the digital potentiometer refers to the position of one or more adjustable contact points in its internal programmable resistor network.

[0026] The main control module is used to control the digital potentiometer to adjust the tap according to the second electrical signal, so as to compensate for the influence of temperature on the sensor. The main control module also receives the first electrical signal output from the oscillation detection module, determines whether the target object is detected, and outputs the corresponding detection result. Optionally, the main control module receives the first electrical signal and the second electrical signal through two analog-to-digital conversion interfaces respectively, and is connected to the digital potentiometer through a serial communication interface.

[0027] The capacitive proximity sensor provided in the embodiment of the present application is provided with a temperature detection module to detect the ambient temperature, the main control module controls the digital potentiometer to adjust its tap position through the ambient temperature, and the digital potentiometer is connected to the oscillation detection module, thereby compensating the first electrical signal output by the oscillation detection module. The embodiment of the present application detects the ambient temperature through an integrated temperature detection module, and dynamically adjusts the first electrical signal by adjusting the tap position of the digital potentiometer, thereby realizing real-time compensation for ambient temperature changes, thereby significantly improving the detection accuracy and environmental adaptability of the sensor, and solving the problems of limited material optimization effect and software compensation requiring a large number of individual calibrations in traditional solutions.

[0028] It should be clear that the purpose of the embodiments of the present application is to provide a solution for real-time compensation of the influence of ambient temperature changes on the detection accuracy of the capacitive proximity sensor through a digital potentiometer, thereby enhancing the stability and reliability of the sensor under different environmental conditions, and the specific implementation method of the temperature detection module and the digital potentiometer can be achieved through conventional technical means. The present application integrates these components into the capacitive proximity sensor system and uses the main control module to coordinate the operation of each component to achieve dynamic compensation for ambient temperature changes.

[0029] Exemplarily, the embodiment of the present application can form a voltage divider circuit through a thermistor and a resistor with a fixed resistance, and connect the output end of the voltage divider circuit to the analog-to-digital conversion interface of the main control module, so as to convert the temperature signal into a second electrical signal, and then the main control module performs analog-to-digital conversion on the second electrical signal to obtain the analog-to-digital conversion value of the ambient temperature. It can be understood that only a basic temperature detection circuit is exemplified here, and it does not mean that the temperature detection module of the embodiment of the present application is limited to the use of this circuit. In fact, when the temperature detection module provided in the embodiment of the present application is applied, factors such as accuracy, power consumption, response speed, cost-effectiveness, compatibility and integration difficulty should also be considered.

[0030] Exemplarily, the digital potentiometer of the embodiment of the present application can be configured to indirectly adjust the first electrical signal by adjusting the amplitude of the oscillation signal through a change in resistance value, thereby performing temperature compensation on the sensor, and can also be configured to directly adjust the first electrical signal by a change in resistance value, thereby performing temperature compensation on the sensor.

[0031] It can be understood that the oscillation detection module and the main control module are both necessary technical features of the capacitive proximity sensor. The purpose of the embodiments of the present application is not to innovate these two modules, so the specific structures of the oscillation detection module and the main control module are not described in detail.

[0032] Exemplarily, the oscillation detection module includes a sensor electrode, an oscillation circuit, and a filter circuit. The oscillation circuit outputs an oscillation signal to the filter circuit, and the amplitude of the oscillation signal changes based on the capacitance change of the sensor electrode. The filter circuit filters the oscillation signal, thereby converting the oscillation frequency change caused by the capacitance change into a voltage change, and finally being received by the analog-to-digital conversion interface of the main control module. Among them, the digital potentiometer can indirectly adjust the first electrical signal by adjusting the amplitude of the oscillation signal by changing the resistance value, or directly adjust the first electrical signal by changing the resistance value, and the embodiment of the present application does not limit this. Optionally, the oscillation detection module may also include a voltage amplifier circuit for amplifying the first electrical signal output by the filter circuit and outputting it to the main control module. It is understandable that only a basic oscillation detection circuit is exemplified here, and it does not mean that the temperature detection module of the embodiment of the present application is limited to use this circuit. In fact, when the temperature detection module provided in the embodiment of the present application is applied, factors such as measurement accuracy and signal resolution, response time, environmental stability, linear adjustment and correction, energy consumption control, economic cost, system compatibility and integration complexity should also be considered.

[0033] In some embodiments, in the capacitive proximity sensor provided by the embodiments of the present application, the main control module is configured as follows: Get the current ambient temperature and determine the preset temperature range to which the ambient temperature belongs.

[0034] The tap of the digital potentiometer is adjusted according to a mapping relationship between a preset temperature range to which the ambient temperature belongs and an adjustment parameter of the digital potentiometer.

[0035] The embodiment of the present application achieves accurate compensation for sensor performance fluctuations caused by changes in ambient temperature by presetting optimal adjustment parameters of the digital potentiometer in different temperature ranges.

[0036] In some embodiments, Figure 2 2 shows another module schematic diagram of a capacitive proximity sensor provided in an embodiment of the present application, such as Figure 2 As shown, the capacitive proximity sensor provided in the embodiment of the present application also includes a storage unit for storing a mapping relationship between a preset temperature range and an adjustment parameter of the digital potentiometer, so that the main control module can adjust the tap of the digital potentiometer according to the mapping relationship between the preset temperature range to which the ambient temperature belongs and the adjustment parameter of the digital potentiometer.

[0037] In some embodiments, the storage unit is a non-volatile memory.

[0038] Based on the above capacitive proximity sensor, an embodiment of the present application further provides a temperature drift compensation method for a capacitive proximity sensor, which is applied to the above capacitive proximity sensor. The method includes a pre-calibration stage and a real-time compensation stage.

[0039] Figure 3 FIG. 4 shows a flow chart of a pre-calibration phase of a temperature drift compensation method for a capacitive proximity sensor provided in an embodiment of the present application. Figure 3 As shown, the pre-calibration phase includes: Step S100: Obtain the analog-to-digital conversion value obtained by sampling at least one capacitive proximity sensor based on the same preset detection distance under multiple preset temperature intervals. Optionally, multiple preset temperature intervals are set based on the application scenario of the capacitive proximity sensor, for example, the preset temperature intervals are set respectively: 15~25℃, 25~35℃, 35~45℃, 45~55℃. Then select one temperature each at 15~25℃, 25~35℃, 35~45℃, and 45~55℃ to test the analog-to-digital conversion value obtained by sampling the capacitive proximity sensor based on the preset detection distance in each temperature environment. The analog-to-digital conversion value is the result obtained by the main control module performing analog-to-digital conversion on the second electrical signal. The preset detection distance can be set based on the application scenario of the capacitive proximity sensor. For example, if the capacitive proximity sensor is used to detect objects within 8 mm, the preset detection distance can be set to 8 mm. In view of the inconsistency of each capacitive proximity sensor, the embodiment of the present application can select multiple capacitive sensors to perform this step.

[0040] It is understandable that the value of the preset temperature range is an empirical value or obtained by experimental testing means, and this application does not limit this. These preset temperature ranges can be adjusted according to specific application scenarios and requirements to ensure the performance and accuracy of the capacitive proximity sensor at different ambient temperatures. For example, in some application scenarios, a finer-grained temperature range may be required to obtain higher compensation accuracy, while in other cases, a wider temperature range may be sufficient to meet the needs. Therefore, the setting of the preset temperature range should comprehensively consider factors such as the actual application conditions, the required measurement accuracy, and the complexity and cost of the system.

[0041] Step S200: Adjust the tap position of the digital potentiometer of the capacitive proximity sensor to calibrate the analog-to-digital conversion value of the capacitive proximity sensor to a preset target analog-to-digital conversion value in each preset temperature range. Optionally, the embodiment of the present application dynamically adjusts the tap position of the digital potentiometer according to a preset target analog-to-digital conversion value through the main control module, thereby ensuring that the analog-to-digital conversion value output by the sensor remains consistent or within a desired range in each preset temperature range.

[0042] Step S300: Acquire adjustment parameters of the digital potentiometer, and generate a mapping relationship between a preset temperature range and the adjustment parameters of the digital potentiometer. Optionally, the mapping relationship is stored in a storage unit of the capacitive proximity sensor to be called by a main control module.

[0043] Figure 4FIG. 4 is a flow chart showing the real-time compensation phase of the temperature drift compensation method for a capacitive proximity sensor provided by an embodiment of the present application. Figure 4 As shown, the real-time compensation stage includes: Step S400: Obtain the current ambient temperature and determine the preset temperature range to which the ambient temperature belongs. Optionally, the embodiment of the present application monitors the ambient temperature in real time through a temperature detection module, and transmits the temperature data to the main control module in the form of an electrical signal. The main control module converts it into a digital signal and determines the preset temperature range to which it belongs.

[0044] Step S500: Adjust the tap of the digital potentiometer according to the mapping relationship between the preset temperature range to which the ambient temperature belongs and the adjustment parameter of the digital potentiometer, so as to calibrate the analog-to-digital conversion value obtained by the capacitive proximity sensor based on the preset detection distance sampling to the target analog-to-digital conversion value. Optionally, the main control module automatically queries the corresponding digital potentiometer adjustment parameter according to the mapping relationship, and sends instructions to the digital potentiometer for adjustment through a serial communication interface such as I2C or SPI, thereby realizing temperature compensation for the capacitive proximity sensor. For example, the preset temperature range includes: 15~25℃, 25~35℃, 35~45℃, 45~55℃, and the ambient temperature at the current moment is 24℃, then the main control module adjusts the tap of the digital potentiometer according to the adjustment parameter of the digital potentiometer corresponding to the preset temperature range of 25~35℃, so that the analog-to-digital conversion value obtained by the capacitive proximity sensor based on the preset detection distance sampling is the target analog-to-digital conversion value.

[0045] The temperature drift compensation method for a capacitive proximity sensor provided in an embodiment of the present application establishes a mapping relationship between a preset temperature range and a digital potentiometer adjustment parameter through a pre-calibration stage, and adjusts the potentiometer tap according to the current ambient temperature in the real-time compensation stage to dynamically calibrate the sensor's analog-to-digital conversion value. Specifically, the pre-calibration stage generates standardized compensation parameters by calibrating the sensor output at different temperatures; the real-time compensation stage quickly matches the corresponding parameters based on the temperature range without relying on complex algorithms or individual sensor data collection. The present application effectively improves the detection consistency of capacitive proximity sensors in a wide temperature environment through standardized calibration procedures and dynamic parameter matching, reduces the workload and cost of individual calibration, and solves the problems of limited material optimization effects and software compensation requiring a large number of individual calibrations in traditional solutions.

[0046] It is understandable that in the embodiment of the present application, the purpose of the pre-calibration stage is to obtain the mapping relationship between each preset temperature interval and the adjustment parameter of the digital potentiometer. Therefore, once the mapping relationship is determined, it is no longer necessary to repeat the pre-calibration stage in the subsequent actual application process, and only the real-time compensation stage needs to be performed.

[0047] It can be understood that in the embodiments of the present application, each step of implementing the compensation stage is executed through a software algorithm, and its implementation method can be flexibly selected and adjusted according to specific application requirements and hardware platforms. Therefore, the embodiments of the present application do not limit the algorithm content.

[0048] In some embodiments, Figure 5 Another flow chart of the pre-calibration phase of the temperature drift compensation method of the capacitive proximity sensor provided by the embodiment of the present application is shown. Figure 5 As shown, before the step S100: obtaining the analog-to-digital conversion value of at least one capacitive proximity sensor sampled at the same preset detection distance in multiple preset temperature intervals, it also includes: Step S10: Obtain an analog-to-digital conversion value of at least one capacitive proximity sensor sampled at a preset detection distance in a reference temperature interval, where the reference temperature interval is one of a plurality of preset temperature intervals. Optionally, the reference temperature interval may be a temperature range under commonly used standard test conditions, such as 25-35°C, or the most commonly used temperature interval may be selected as the reference temperature interval according to a specific application scenario. The embodiment of the present application can provide a reference benchmark for a subsequent calibration process by performing preliminary testing within the reference temperature interval.

[0049] Step S20: Adjust the tap position of the digital potentiometer of each capacitive proximity sensor, and calibrate the analog-to-digital conversion value of each capacitive proximity sensor to the target analog-to-digital conversion value. Optionally, the main control module can dynamically adjust the tap position of the digital potentiometer according to the preset target analog-to-digital conversion value to ensure that the output of all sensors is consistent within the reference temperature range. This reduces the individual differences between the sensors and provides a unified basis for subsequent compensation in different temperature ranges.

[0050] In some embodiments, Figure 6 Another flow chart of the pre-calibration phase of the temperature drift compensation method of the capacitive proximity sensor provided by the embodiment of the present application is shown. Figure 6 As shown, in the embodiment of the present application, step S300: obtaining the adjustment parameters of the digital potentiometer, and generating a mapping relationship between the preset temperature range and the adjustment parameters of the digital potentiometer, includes: Step S310: Obtain the step difference between the digital potentiometer tap position of the capacitive proximity sensor in each preset temperature interval and the digital potentiometer tap position of the capacitive proximity sensor in the reference temperature interval. For example, the preset temperature interval includes: 15~25℃, 25~35℃, 35~45℃, 45~55℃, the reference temperature interval is 25~35℃, and the digital potentiometer tap position corresponding to the reference temperature interval is the initial position. When the preset temperature interval changes from 25~35℃ to 35~45℃, the digital potentiometer needs to decrease by 3 steps from the initial position, and the step difference is -3 at this time; when the preset temperature interval changes from 35~35℃ to 45~55℃, the digital potentiometer needs to decrease by 5 steps from the initial position, and the step difference is -5 at this time; when the preset temperature interval changes from 25~35℃ to 15~25℃, the digital potentiometer needs to increase by 1 step from the initial position, and the step difference is +1 at this time.

[0051] Step S320: Generate a mapping relationship between a preset temperature range and a step difference, for example, a plurality of preset temperature ranges 15-25°C, 25-35°C, 35-45°C, 45-55°C are mapped to step differences of 1, 0, -3, -5 respectively.

[0052] The temperature drift compensation method of the capacitive proximity sensor provided in the embodiment of the present application uses the step difference between the tap position of the digital potentiometer of the capacitive proximity sensor in each preset temperature interval and the reference temperature interval as the adjustment parameter of the digital potentiometer, thereby achieving accurate compensation for the sensor performance fluctuation caused by ambient temperature changes.

[0053] In some embodiments, Figure 7 Another flow chart of the pre-calibration phase of the temperature drift compensation method of the capacitive proximity sensor provided by the embodiment of the present application is shown. Figure 7 As shown, in the embodiment of the present application, step S300: obtaining the adjustment parameters of the digital potentiometer, and generating a mapping relationship between the preset temperature range and the adjustment parameters of the digital potentiometer, includes: Step S330: obtaining adjustment parameters of the digital potentiometers of each capacitive proximity sensor in a preset temperature range.

[0054] Step S340: According to a preset screening strategy, one adjustment parameter is selected from the adjustment parameters of the multiple digital potentiometers corresponding to the preset temperature range to form a mapping relationship with the preset temperature range.

[0055] Optionally, in the embodiment of the present application, due to the inconsistency of each capacitive proximity sensor, multiple capacitive sensors can be selected to perform the pre-calibration stage. In the same preset temperature range, the adjustment parameters of the digital potentiometers of different capacitive proximity sensors are not necessarily the same. In view of this, the embodiment of the present application uses a preset screening strategy to select only one adjustment parameter as the mapping result of the preset temperature range for each preset temperature range. This ensures that the system can use the optimal adjustment parameters for compensation, thereby improving overall consistency and reliability.

[0056] In some embodiments, in the temperature drift compensation method of the capacitive proximity sensor provided in the embodiments of the present application, the preset screening strategy includes: one of the first screening strategy, the second screening strategy, the third screening strategy, and the fourth screening strategy.

[0057] Among them, the first screening strategy is: based on the median of the adjustment parameters of the digital potentiometers of each capacitive proximity sensor, select an adjustment parameter to form a mapping relationship with the preset temperature range, that is, use the median of the adjustment parameters of each digital potentiometer as the mapping result of the preset temperature range. The second screening strategy is: based on the mode of the adjustment parameters of the digital potentiometers of each capacitive proximity sensor, select an adjustment parameter to form a mapping relationship with the preset temperature range, that is, use the mode of the adjustment parameters of each digital potentiometer as the mapping result of the preset temperature range. The third screening strategy is: based on the statistical distribution characteristics of the adjustment parameters of the digital potentiometers of each capacitive proximity sensor, such as normal distribution / skewed distribution and other characteristics, select an adjustment parameter to form a mapping relationship with the preset temperature range. The fourth screening strategy is: based on the preset reference parameter, select one of the adjustment parameters of the digital potentiometers of each capacitive proximity sensor to form a mapping relationship with the preset temperature range, and the preset reference parameter can be an empirical value, an experimental value, etc.

[0058] It should be clear that the embodiments of the present application do not impose any restrictions on the specific strategies of the preset screening strategies. In practical applications, appropriate screening strategies should be flexibly selected according to specific application requirements and actual conditions.

[0059] In some embodiments, Figure 8 Another flow chart of the real-time compensation phase of the temperature drift compensation method of the capacitive proximity sensor provided by the embodiment of the present application is shown. Figure 8 As shown, the temperature drift compensation method of the capacitive proximity sensor provided in the embodiment of the present application, before the step S400: adjusting the tap of the digital potentiometer according to the mapping relationship between the preset temperature range to which the ambient temperature belongs and the adjustment parameter of the digital potentiometer, also includes: Step S80: Determine whether the current ambient temperature satisfies the first execution condition or the second execution condition. Step S90: If the ambient temperature satisfies the first execution condition or the second execution condition, the step of adjusting the tap of the digital potentiometer according to the mapping relationship between the preset temperature range to which the ambient temperature belongs and the adjustment parameter of the digital potentiometer is executed.

[0060] Otherwise, skip step: adjust the tap of the digital potentiometer according to the mapping relationship between the preset temperature range to which the ambient temperature belongs and the adjustment parameter of the digital potentiometer.

[0061] Among them, the first execution condition is: the ambient temperature at the current moment and the ambient temperature at the previous moment do not belong to the same preset temperature interval, and the ambient temperature at the current moment and the ambient temperature at the previous moment belong to the same transition interval, and the ambient temperature at the current moment and the ambient temperature at the previous two moments do not belong to the same preset temperature interval. The second execution condition is: the ambient temperature at the current moment and the ambient temperature at the previous moment do not belong to the same preset temperature interval, and the ambient temperature at the current moment and the ambient temperature at the previous moment do not belong to the same transition interval. The transition interval is an interval formed by extending the boundary of two adjacent preset temperature intervals to both sides by a predetermined temperature. Optionally, if the ambient temperature at the current moment meets the first execution condition, it means that the ambient temperature does not repeatedly jump at the critical point of the adjacent preset temperature interval, so the tap of the digital potentiometer should be adjusted. For example, the adjacent preset temperature intervals are 15~25℃ and 25~35℃, and the transition interval is 24~26℃. If the ambient temperature jumps from 24.5℃ to the temperature interval 25.5℃, and then jumps to 24.5℃, that is, the ambient temperature repeatedly jumps in the transition interval at this time, so there is no need to adjust the tap of the digital potentiometer. If the second execution adjustment is satisfied, it means that the ambient temperature changes from a preset temperature range to a new preset temperature range, and therefore the tap of the digital potentiometer should be adjusted.

[0062] The temperature drift compensation method of the capacitive proximity sensor provided in the embodiment of the present application solves the problem of frequent adjustment of the tap position of the digital potentiometer caused by repeated jumps of the ambient temperature at the critical points of adjacent preset temperature intervals by setting transition intervals and execution conditions.

[0063] The above contents are further detailed descriptions of the present application in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application, which should be regarded as the protection scope of the present application.

Claims

1. A capacitive proximity sensor, characterized in that: include: an oscillation detection module, comprising a sensor electrode, for outputting an oscillation signal according to a change in capacitance of the sensor electrode, and converting the oscillation signal into a first electrical signal; A temperature detection module, used to detect the current ambient temperature and output a second electrical signal; A digital potentiometer, connected to the oscillation detection module, and used to adjust the first electrical signal output by the oscillation detection module by adjusting the tap position; The main control module is used to control the digital potentiometer to adjust the tap according to the second electrical signal, and output the detection result according to the first electrical signal.

2. The capacitive proximity sensor according to claim 1, characterized in that: The main control module is configured as follows: Obtain the current ambient temperature and determine the preset temperature range to which the ambient temperature belongs; The tap of the digital potentiometer is adjusted according to a mapping relationship between a preset temperature interval to which the ambient temperature belongs and an adjustment parameter of the digital potentiometer.

3. The capacitive proximity sensor according to claim 2, wherein: The capacitive proximity sensor also includes: The storage unit is used to store the mapping relationship between the preset temperature range and the adjustment parameter of the digital potentiometer.

4. A method for compensating temperature drift of a capacitive proximity sensor, characterized in that: Applied to the capacitive proximity sensor as claimed in claim 1, the method comprises a pre-calibration phase and a real-time compensation phase; The pre-calibration stage includes: Obtaining analog-to-digital conversion values ​​of at least one capacitive proximity sensor sampled at a same preset detection distance in multiple preset temperature ranges; Adjusting the tap position of the digital potentiometer of the capacitive proximity sensor to calibrate the analog-to-digital conversion value of the capacitive proximity sensor to a preset target analog-to-digital conversion value in each of the preset temperature ranges; Acquiring an adjustment parameter of the digital potentiometer, and generating a mapping relationship between the preset temperature range and the adjustment parameter of the digital potentiometer; The real-time compensation stage includes: Obtain the current ambient temperature and determine the preset temperature range to which the ambient temperature belongs; The tap of the digital potentiometer is adjusted according to a mapping relationship between a preset temperature interval to which the ambient temperature belongs and an adjustment parameter of the digital potentiometer, so as to calibrate the analog-to-digital conversion value obtained by sampling the capacitive proximity sensor based on the preset detection distance to the target analog-to-digital conversion value.

5. The temperature drift compensation method of a capacitive proximity sensor according to claim 4, characterized in that: Before the step of obtaining the analog-to-digital conversion value of at least one capacitive proximity sensor sampled at the same preset detection distance in multiple preset temperature intervals, the step further includes: Acquire an analog-to-digital conversion value of at least one of the capacitive proximity sensors sampled based on the preset detection distance in a reference temperature interval, wherein the reference temperature interval is one of the plurality of preset temperature intervals; The tap position of the digital potentiometer of each of the capacitive proximity sensors is adjusted to calibrate the analog-to-digital conversion value of each of the capacitive proximity sensors to the target analog-to-digital conversion value.

6. The temperature drift compensation method of a capacitive proximity sensor according to claim 5, characterized in that: The step of obtaining the adjustment parameter of the digital potentiometer and generating a mapping relationship between the preset temperature range and the adjustment parameter of the digital potentiometer comprises: Acquire a step difference between a tap position of a digital potentiometer of the capacitive proximity sensor in each of the preset temperature intervals and a tap position of the digital potentiometer of the capacitive proximity sensor in the reference temperature interval; A mapping relationship between the preset temperature interval and the step difference is generated.

7. The temperature drift compensation method of a capacitive proximity sensor according to claim 4, characterized in that: The step of obtaining the adjustment parameter of the digital potentiometer and generating a mapping relationship between the preset temperature range and the adjustment parameter of the digital potentiometer comprises: Obtaining adjustment parameters of the digital potentiometers of each of the capacitive proximity sensors in the preset temperature range; According to a preset screening strategy, one adjustment parameter is selected from the adjustment parameters of a plurality of digital potentiometers corresponding to the preset temperature interval to form a mapping relationship with the preset temperature interval.

8. The temperature drift compensation method of a capacitive proximity sensor according to claim 7, characterized in that: The preset screening strategy includes: one of the first screening strategy, the second screening strategy, the third screening strategy, and the fourth screening strategy; The first screening strategy is: based on the median of the adjustment parameters of the digital potentiometers of the capacitive proximity sensors, selecting an adjustment parameter to form a mapping relationship with the preset temperature range; The second screening strategy is: based on the mode of the adjustment parameters of the digital potentiometers of the capacitive proximity sensors, selecting an adjustment parameter to form a mapping relationship with the preset temperature range; The third screening strategy is: based on the statistical distribution characteristics of the adjustment parameters of the digital potentiometers of the capacitive proximity sensors, selecting an adjustment parameter to form a mapping relationship with the preset temperature range; The fourth screening strategy is: based on a preset reference parameter, one of the adjustment parameters of the digital potentiometer of each of the capacitive proximity sensors is selected to form a mapping relationship with the preset temperature range.

9. The temperature drift compensation method of a capacitive proximity sensor according to claim 4, characterized in that: Before the step of adjusting the tap of the digital potentiometer according to the mapping relationship between the preset temperature interval to which the ambient temperature belongs and the adjustment parameter of the digital potentiometer, the step further includes: Determine whether the current ambient temperature meets the first execution condition or the second execution condition, If the ambient temperature satisfies the first execution condition or the second execution condition, the steps of: adjusting the tap of the digital potentiometer according to a mapping relationship between a preset temperature interval to which the ambient temperature belongs and an adjustment parameter of the digital potentiometer; Otherwise, skip the step of: adjusting the tap of the digital potentiometer according to the mapping relationship between the preset temperature interval to which the ambient temperature belongs and the adjustment parameter of the digital potentiometer; The first execution condition is that the ambient temperature at the current moment and the ambient temperature at the previous moment do not belong to the same preset temperature interval, and the ambient temperature at the current moment and the ambient temperature at the previous moment belong to the same transition interval, and the ambient temperature at the current moment and the ambient temperatures at the previous two moments do not belong to the same preset temperature interval; The second execution condition is that the ambient temperature at the current moment and the ambient temperature at the previous moment do not belong to the same preset temperature range, and the ambient temperature at the current moment and the ambient temperature at the previous moment do not belong to the same transition range; The transition interval is an interval formed by extending the boundary of two adjacent preset temperature intervals to both sides with predetermined temperatures.

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