A control method, a control device and a control system

Abstract

The present invention discloses a control method, a control device and a control system. The control method comprises: obtaining first displacement information of a measurement object through a capacitive sensor; obtaining at least one kind of environmental information through at least one environmental sensor in the same environment as the capacitive sensor; obtaining first compensation information and compensating the first displacement information according to an environment and displacement model and at least one kind of environmental information. In the present invention, an environment and displacement model is pre-stored in the control device, which can achieve the effect of compensating the measurement result of the capacitive sensor according to the environmental information, reduce the interference of the environmental information, and improve the displacement measurement accuracy; there is no need to improve the structural design of the capacitive sensor, nor to adopt complex signal processing technology, avoiding the high cost and complex manufacturing process required for hardware improvement, and is not limited to application scenarios. Even in some special cases such as drastic environmental changes or long duration, high displacement measurement accuracy can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of position measurement, and in particular to a control method, a control device and a control system. Background Art

[0002] On precision motion platforms and optical platforms, capacitive sensors are widely used in position detection due to their high precision and fast response.

[0003] The position measurement accuracy of capacitive sensors is easily affected by many factors, such as the influence of the sensor's own parameters and environmental factors.

[0004] At present, the impact of external factors on the position measurement accuracy of capacitive sensors is mainly improved from two aspects. On the one hand, the structure of the capacitive sensor is improved through hardware design to make the capacitive sensor insensitive to environmental changes. On the other hand, signal processing technology, such as filtering and denoising, is used to correct the output signal of the capacitive transmitter and reduce environmental impact.

[0005] Although the impact of environmental interference on capacitive sensors is reduced to a certain extent, there are problems of high cost and limited improvement effect. Summary of the invention

[0006] The present invention provides a control method, a control device and a control system to improve the displacement detection accuracy of a capacitive sensor.

[0007] According to one aspect of the present invention, there is provided a control method, comprising:

[0008] Acquiring first displacement information of the measurement object through a capacitive sensor;

[0009] Acquiring at least one type of environmental information through at least one environmental sensor in the same environment as the capacitive sensor;

[0010] According to the environment and displacement model and the at least one environmental information, first compensation information is obtained and the first displacement information is compensated.

[0011] According to another aspect of the present invention, there is provided a control device, comprising:

[0012] A displacement measurement module, used for acquiring first displacement information of a measurement object through a capacitive sensor;

[0013] An environment sampling module, used to obtain at least one kind of environment information through at least one environment sensor in the same environment as the capacitive sensor;

[0014] The compensation module is used to obtain first compensation information and compensate the first displacement information according to the environment and displacement model and the at least one environmental information.

[0015] According to another aspect of the present invention, there is provided a control system, comprising: a capacitive sensor, at least one environmental sensor in the same environment as the capacitive sensor, and the control device as described above;

[0016] The control device is electrically connected to the capacitive sensor and the at least one environmental sensor, respectively.

[0017] In the present invention, the control device pre-stores an environment and displacement model, and the corresponding first compensation information can be obtained according to the environment information, and then the first compensation information is used to compensate the first displacement information, thereby achieving the effect of compensating the measurement result of the capacitive sensor according to the environment information, which can reduce the interference of the environment information on the measurement result of the capacitive sensor and improve the displacement measurement accuracy. In the present invention, the compensation information is calculated and compensated by the environment and displacement model, so that the distance (gap) of the measurement object detected by the capacitive sensor is closer to the actual situation, and a part of the interference factors of the environment are eliminated, so that the measurement position accuracy is higher and the stability is better, and there is no need to improve the structural design of the capacitive sensor, and there is no need to use complex signal processing technology, avoiding the high cost and complex manufacturing process required for hardware improvement, which is conducive to large-scale application, and is not limited to the application scenario. Even in some special cases such as drastic environmental changes or long duration, high-precision displacement measurement can be guaranteed.

[0018] 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

[0019] 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.

[0020] Figure 1 is a schematic diagram of a control system provided by an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of a control method provided by an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of a capacitive sensor provided by an embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of an environmental chamber provided by an embodiment of the present invention;

[0024] Figure 5 is a schematic diagram of another control system provided by an embodiment of the present invention;

[0025] Figure 6 It is a schematic diagram of the humidity changes in a device;

[0026] Figure 7 is a schematic diagram of a control device provided by an embodiment of the present invention;

[0027] Figure 8 is a schematic diagram of another control system provided by an embodiment of the present invention;

[0028] Fig. 9 It is a schematic diagram of a motion control mechanism provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] 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.

[0030] 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.

[0031] Figure 1 is a schematic diagram of a control system provided by an embodiment of the present invention. This embodiment is applicable to the case of measuring the displacement of the measurement object 10. Figure 1As shown, the control system 100 includes: a capacitive sensor 101, at least one environmental sensor 102 in the same environment as the capacitive sensor 101, and a control device 103; the control device 103 is electrically connected to the capacitive sensor 101 and the at least one environmental sensor 102 respectively.

[0032] Based on the above control system 100 , an embodiment of the present invention provides a control method.

[0033] Figure 2 It is a schematic diagram of a control method provided by an embodiment of the present invention. This embodiment is applicable to the case of measuring the displacement of the measuring object 10. The control method can be executed by the control device 103 in the present invention. The control device 103 can be implemented in the form of hardware and / or software. The control device 103 can be configured in the control system 100 in the present invention. The control system 100 can run independently or be integrated in other devices. Exemplarily, the control system 100 can be integrated in a precision motion platform and an optical platform.

[0034] like Figure 2 As shown, the control method provided by the embodiment of the present invention includes:

[0035] Step 210: Acquire first displacement information of the measurement object through a capacitive sensor;

[0036] Step 220: Acquire at least one type of environmental information through at least one environmental sensor in the same environment as the capacitive sensor;

[0037] Step 230: Obtain first compensation information and compensate the first displacement information according to the environment and displacement model and at least one environmental information.

[0038] In this embodiment, the capacitive sensor 101 is disposed near the measuring object 10, and the capacitive sensor 101 can collect motion information of the measuring object 10. When the measuring object 10 moves, the capacitive sensor 101 collects the motion information of the measuring object 10, and generates displacement information according to the motion information of the measuring object 10, and the displacement information is the first displacement information. The model or structure of the capacitive sensor 101 is not specifically limited, and the measuring object 10 can be any object whose displacement needs to be measured.

[0039] The environmental sensor 102 and the capacitive sensor 101 are in the same environment. The environmental sensor 102 can be arranged near the capacitive sensor 101, or the environmental sensor 102 can be arranged in direct contact with the capacitive sensor 101. The control system 100 includes one or more environmental sensors 102. Figure 1Only one environment sensor 102 is shown in the figure. The environment sensor 102 can collect environment information of the environment; illustratively, if the control system 100 includes a humidity sensor, the environment information of the environment collected by the humidity sensor is the environment humidity information; if the control system 100 includes a temperature sensor, the environment information of the environment collected by the temperature sensor is the environment temperature information; and so on. Since the environment sensor 102 is arranged adjacent to or in contact with the capacitive sensor 101, the environment information of the environment collected by the environment sensor 102 can be regarded as the environment information of the environment in which the capacitive sensor 101 is located.

[0040] The control device 103 is electrically connected to the environmental sensor 102 and the capacitive sensor 101, respectively. The control device 103 pre-stores an environment and displacement model, which calculates compensation information based on environmental information. The compensation information obtained by the control device 103 according to the environmental information collected by the environmental sensor 102 is the first compensation information, and the control device 103 uses the first compensation information to compensate the first displacement information. The control device 103 can be a microprocessor, a single-chip microcomputer or other device capable of data processing, and the model or structure of the control device 103 is not specifically limited.

[0041] It should be noted that the control system 100 also includes other components, which will not be described in detail here.

[0042] In this embodiment, the control device 103 is electrically connected to the capacitive sensor 101. The capacitive sensor 101 transmits the acquired first displacement information to the control device 103. The first displacement information generated by the capacitive sensor 101 according to the motion information of the measurement object 10 may be a capacitance analog quantity or a voltage signal. The control device 103 calculates the displacement amount according to the first displacement information, and the obtained displacement amount is the displacement measurement value of the measurement object 10.

[0043] The control device 103 is electrically connected to the environmental sensor 102. The environmental sensor 102 transmits the collected environmental information to the control device 103. The environmental information generated by the environmental sensor 102 may be an analog signal or a voltage signal. The control device 103 substitutes the environmental information transmitted by the environmental sensor 102 into the environment and displacement model to obtain compensation information corresponding to the environmental information. The compensation information obtained by the control device 103 based on the environmental information collected by the environmental sensor 102 is the first compensation information. The control device 103 calculates the displacement amount based on the first compensation information, and the obtained displacement amount is the displacement compensation value.

[0044] The control device 103 uses the displacement compensation value calculated according to the first compensation information to compensate the displacement measurement value calculated according to the first displacement information, and the displacement amount obtained after compensation is determined as the actual displacement value of the measured object 10. Specifically, if the displacement compensation value and the displacement measurement value are both distance values, the actual displacement value can be obtained by directly adding the displacement compensation value to the displacement measurement value. However, different compensation algorithms need to be used in other different situations. For example, the displacement compensation value may be a rate of change or other proportional parameters, and the corresponding compensation algorithm needs to be used for compensation to obtain the actual displacement value.

[0045] In the present invention, the control device pre-stores an environment and displacement model, and the corresponding first compensation information can be obtained according to the environment information, and then the first compensation information is used to compensate the first displacement information, thereby achieving the effect of compensating the measurement result of the capacitive sensor according to the environment information, which can reduce the interference of the environment information on the measurement result of the capacitive sensor and improve the displacement measurement accuracy. In the present invention, the compensation information is calculated and compensated by the environment and displacement model, so that the distance (gap) of the measurement object detected by the capacitive sensor is closer to the actual situation, and a part of the interference factors of the environment are eliminated, so that the measurement position accuracy is higher and the stability is better, and there is no need to improve the structural design of the capacitive sensor, and there is no need to use complex signal processing technology, avoiding the high cost and complex manufacturing process required for hardware improvement, which is conducive to large-scale application, and is not limited to the application scenario. Even in some special cases such as drastic environmental changes or long duration, high-precision displacement measurement can be guaranteed.

[0046] Figure 3 is a schematic diagram of a capacitive sensor provided by an embodiment of the present invention, Figure 3 The capacitive sensor 101 shown can be applied to the control system 100 provided by the present invention. However, in the control system 100 provided by the present invention, the type of the capacitive sensor 101 that can be used is not limited to Figure 3 As shown, only Figure 3 The capacitive sensor 101 is used as an example for explanation. Figure 3 As shown, the capacitive sensor 101 is mainly composed of the following parts: an electrode group, an insulating medium and a packaging protection layer.

[0047] The core part of the capacitive sensor 101 is the electrode group, which usually includes two parallel electrodes, and a capacitor is formed between the two parallel electrodes. The electrodes of the electrode group can be parallel plates, cables, or other geometric shapes, depending on the application. Figure 3 As shown, the electrode group of the capacitive sensor 101 includes a guard ring electrode 111 and a measuring electrode 112 .

[0048] The capacitive sensor 101 also includes an insulating medium, which is a material filled between the electrodes. The insulating medium is usually air, vacuum or other insulating materials. The dielectric constant of the insulating medium will affect the capacitance of the capacitive sensor 101. Figure 3 As shown, the insulating medium of the capacitive sensor 101 includes an insulating medium 113 filled between the guard ring electrode 111 and the measuring electrode 112 , and also includes an insulating medium 114 filled between the guard ring electrode 111 and the housing 115 .

[0049] The capacitive sensor 101 further includes a packaging protection layer, which can protect the capacitive sensor 101 from environmental influences, such as preventing humidity, temperature, and mechanical damage from affecting the capacitive sensor 101. Figure 3 As shown, the packaging protection layer of the capacitive sensor 101 includes a shell 115. The shell 115 serves as a shell of the capacitive sensor 101 and can protect the internal components of the capacitive sensor 101. The shell 115 can also serve as a measurement ground.

[0050] Capacitive sensor 101 is connected to the measurement circuit and signal processing unit (not shown in Figure 3 As shown in . The measuring circuit includes a plurality of electronic components with different functions for detecting and measuring capacitance changes. Common measuring circuits include oscillator circuits, bridge circuits and microprocessor control circuits. The signal processing unit is used to process the signal obtained from the measuring circuit so as to convert it into a readable output signal. The signal processing unit may include an amplifier, a filter and an analog-to-digital converter. The displacement signal collected by the capacitance sensor 101 passes through a preamplifier, a demodulator, and then an A / D conversion. Finally, the microprocessor calculates, filters, and other methods to process the data before outputting it to the host computer software.

[0051] like Figure 3 As shown, the selected capacitive sensor 101 adopts a three-axis design of a measuring electrode 112, a guard ring electrode 111 and a measuring ground 115, which can generate a protective electric field 116 and achieve a uniform and stable electric field 117. Based on this, the capacitive sensor 101 can achieve high-precision measurement with the highest signal stability. Through the coordinated work of multiple components, the capacitive sensor 101 can accurately detect and measure changes in capacitance, thereby achieving measurement and control of physical quantities (such as position, humidity, pressure, etc.). In this embodiment, the capacitive sensor 101 is mainly used for position detection. Among them, the conductor 118 is the measurement object.

[0052] Optionally, at least one environmental sensor includes a humidity sensor; the environment and displacement model includes a first environmental mathematical model, and the first environmental mathematical model is: ; Wherein, D(RH(t)) is the first compensation information, RH(t) is the ambient humidity information collected by the humidity sensor, k is the proportional coefficient, and b is a constant.

[0053] In this embodiment, the control device has a first environment mathematical model: , where k and b are both known numbers. Before leaving the factory, k and b are obtained by experimental calculation, and the first environment mathematical model is constructed based on them, and the first environment mathematical model is stored in the control device. The control system may include a humidity sensor, and the humidity sensor can collect environmental humidity information in the environment.

[0054] In practical applications, the first environmental mathematical model is to calculate the first compensation information D(RH(t)) based on the environmental humidity information RH(t) collected by the humidity sensor, and obtain the displacement compensation value according to the first compensation information. Specifically, the humidity sensor transmits the collected environmental humidity information to the control device, and the control device performs signal processing on the environmental humidity information collected by the humidity sensor to obtain the corresponding environmental humidity value RH(t). The control device substitutes the environmental humidity value RH(t) into the first environmental mathematical model, and then calculates the first compensation information D(RH(t)), where the first compensation information D(RH(t)) is the displacement compensation value. The control device uses the first compensation information to compensate the first displacement information, and the displacement obtained after compensation is determined as the actual displacement value of the measured object.

[0055] In the present embodiment, humidity compensation is performed by software. Specifically, a first environmental mathematical model is pre-stored in the control device. The first environmental mathematical model is based on the environmental humidity information to calculate the first compensation information, and then the first compensation information related to the environmental humidity information is used to compensate the first displacement information. In this way, the effect of compensating the measurement result of the capacitive sensor according to the environmental humidity can be achieved, the interference of the environmental humidity on the measurement result of the capacitive sensor can be reduced, and the displacement measurement accuracy can be improved. Even in certain special circumstances such as when the environmental humidity changes drastically or lasts for a long time, the control device can quickly obtain the first compensation information based on the first environmental mathematical model and the environmental humidity information and then perform displacement compensation, thereby ensuring high-precision displacement measurement.

[0056] It should be noted that before leaving the factory, the control device needs to store the first environment mathematical model in advance, that is, k and b need to be calculated through multiple tests before leaving the factory, and then the first environment mathematical model is constructed. The test can be carried out in an environmental chamber to construct the first environment mathematical model.

[0057] Figure 4 Schematic diagram of an environmental chamber provided by an embodiment of the present invention. Figure 4As shown, the environmental chamber 20 should maintain constant temperature, constant pressure, no magnetism, and cleanliness. The optional constant temperature is 22±0.1K, the constant pressure is 101325±100Pa, there is no electromagnetic interference and no magnetic field interference, and the humidity of the clean environmental chamber 20 can be precisely adjusted, but the environmental conditions such as constant pressure and constant temperature are not limited to the above values ​​if the test allows. The environmental chamber 20 is provided with a measuring object 10, a capacitive sensor 101, and a humidity sensor 121. The measuring object 10 is a static detection object. The measuring object 10, the capacitive sensor 101, and the humidity sensor 121 are fixedly constrained and free from vibration, noise, airflow disturbance, etc. The capacitive sensor 101 and the static detection object 10 maintain a constant relative position, thus eliminating other environmental influences (such as temperature, vibration, noise), and the influence relationship of environmental humidity on the distance detected by the capacitive sensor 101 to the measuring object 10 can be accurately found, which is conducive to providing accurate displacement compensation parameters in subsequent compensation control. The capacitive sensor 101 is fixed at a position about S0 away from the surface of the static detection object 10, and S0 can be selected as 0.1mm. The detection surface of the capacitive sensor 101 is basically parallel to the surface of the static detection object 10. The measurable range of the capacitive sensor 101 is 0.2mm, the static resolution is 0.15nm, the dynamic resolution is 4nm, and the linearity is ≤±0.2%FSO. The working parameters of the capacitive sensor 101 and S0 are not limited to the above values. Relevant practitioners can reasonably select the model of the capacitive sensor and design the value of S0 according to the product requirements.

[0058] Figure 4 The humidity of the environmental chamber 20 is adjustable. The test process is as follows:

[0059] In the first test phase, the humidity sensor 121 collects the ambient humidity to obtain the humidity value RH(1), and the capacitance sensor 101 detects the distance from the static detection object 10 to obtain the distance S(1). Then, the first set of data includes RH(1) and its corresponding S(1);

[0060] In the second test phase, the humidity is adjusted, the humidity sensor 121 collects the ambient humidity to obtain the humidity value RH(2), and the capacitance sensor 101 detects the distance from the static detection object 10 to obtain the distance S(2). Then, the second set of data includes RH(2) and its corresponding S(2);

[0061] By analogy, multiple tests were conducted to obtain multiple sets of data covering a wide range of humidity and distance;

[0062] For any set of data, the humidity is corrected until the distance detected by the capacitive sensor 101 is equal to S0. That is, by adjusting the humidity RH in each set of data, S(1)=S(2)=…=S0, the functional relationship between the actual distance S detected by the capacitive sensor 101 and the influence of the ambient humidity RH can be found, the detection distance S of the capacitive sensor 101 is monitored for different ambient humidity, k and b are determined by filtering and fitting methods, and the first environmental mathematical model is constructed, which can be regarded as a humidity compensation algorithm. The first environmental mathematical model is written into the control device.

[0063] As described above, a high-precision humidity sensor can be selected, the operating temperature range of the humidity sensor is -40°C to 150°C, the relative humidity measurement range is 0% to 100%RH, and the accuracy can reach ±0.2%FS, which fully meets the requirements of the present invention. The humidity sensor is installed near the capacitive sensor to accurately monitor the change of environmental humidity. The humidity sensor can be connected to the control device through the RS-485 interface to transmit the monitored humidity data to the control device in real time.

[0064] The at least one environmental sensor may include a humidity sensor and a temperature sensor; the environment and displacement model may include a second environment mathematical model and a dielectric compensation mapping table, and the second environment mathematical model is:

[0065] ;

[0066] Among them, Er(t) is the dielectric constant, n, R and V are coefficients related to temperature and gas, T(t) is the ambient temperature information collected by the temperature sensor, n d is the refractive index of air, a is the coefficient related to humidity, RH(t) is the ambient humidity information collected by the humidity sensor, and P0 is the standard air pressure;

[0067] The dielectric compensation mapping table includes a plurality of different dielectric constants and compensation information corresponding to each dielectric constant.

[0068] In this embodiment, the control device has a second environment mathematical model and a dielectric compensation mapping table, where n, R, n d , a, P0 and V are all known numbers, among which the standard air pressure P0 can be 101.325 kPa, and the air refractive index n d Usually it is 1.000277 under standard conditions. Before leaving the factory, n, R, a and V are calculated through experiments to construct a second environment mathematical model and a dielectric compensation mapping table, and store them in the control device. The control system may include a humidity sensor and a temperature sensor. The humidity sensor can collect ambient humidity information in the environment, and the temperature sensor can collect ambient temperature information in the environment.

[0069] In practical applications, the second environment mathematical model is to calculate the second dielectric constant Er(t) based on the ambient temperature information T(t) collected by the temperature sensor and the ambient humidity information RH(t) collected by the humidity sensor. The dielectric compensation mapping table includes multiple different dielectric constants and compensation information corresponding to each dielectric constant. The compensation information corresponding to the second dielectric constant Er(t), i.e., the first compensation information, can be found from the dielectric compensation mapping table.

[0070] Specifically, the humidity sensor transmits the collected environmental humidity information to the control device, and the control device performs signal processing on the environmental humidity information collected by the humidity sensor to obtain the corresponding environmental humidity value RH(t). The temperature sensor transmits the collected environmental temperature information to the control device, and the control device performs signal processing on the environmental temperature information collected by the temperature sensor to obtain the corresponding environmental temperature value T(t). The control device substitutes the environmental humidity value RH(t) and the environmental temperature value T(t) into the second environmental mathematical model, and then calculates the second dielectric constant Er(t), and then finds the compensation information corresponding to the second dielectric constant Er(t) from the dielectric compensation mapping table as the first compensation information, where the first compensation information is the displacement compensation value. The control device uses the first compensation information to compensate the first displacement information, and the displacement obtained after compensation is determined as the actual displacement value of the measured object.

[0071] In this embodiment, humidity compensation is performed by software. A second environmental mathematical model and a dielectric compensation mapping table are pre-stored in the control device. The first compensation information is calculated based on the environmental humidity information and the environmental temperature information, and then the first displacement information is compensated. In this way, the effect of compensating the measurement results of the capacitive sensor according to the environmental humidity and temperature can be achieved, and the interference of the environmental humidity and temperature on the measurement results of the capacitive sensor can be reduced, and the displacement measurement accuracy can be improved. Even in certain special circumstances such as drastic or long-lasting changes in environmental humidity and / or humidity, the control device can quickly obtain the first compensation information based on the second environmental mathematical model and the dielectric compensation mapping table and then perform displacement compensation, thereby ensuring high-precision displacement measurement.

[0072] It should be noted that before leaving the factory, the second environment mathematical model needs to be pre-stored in the control device, that is, n, R, a and V need to be calculated through multiple tests before leaving the factory, and then the second environment mathematical model is constructed. It can be understood that the construction process of the second environment mathematical model is similar to the construction process of the first environment mathematical model. The difference is that the variables that need to be considered in the construction process of the second environment mathematical model include humidity and temperature, and the specific process will not be repeated here.

[0073] The control device needs to pre-store a dielectric compensation mapping table. The distance S detected by the capacitive sensor from the measured object and the air dielectric constant satisfy the following relationship: , where C0 is the rated value of the capacitive sensor, C is the capacitance value of the capacitive sensor, d is the target displacement value of the measured object, S is the distance between the capacitive sensor and the measured object, Er is the calculated value of the dielectric constant, E2 is the dielectric constant of the insulator, i.e., the standard value of the dielectric constant, the ratio of C0 / C is a constant, d and E2 are known values, and obviously, the larger Er is, the smaller S is. In the test in the environmental chamber, for any set of data, the humidity and temperature are corrected until the distance detected by the capacitive sensor 101 is equal to S0, so that the distance compensation value and the corresponding dielectric constant in a set of data can be calculated. In this way, a dielectric compensation mapping table is constructed and written into the control device.

[0074] The at least one environmental sensor may include a humidity sensor and an air pressure sensor; the environment and displacement model may include a third environmental mathematical model and a dielectric compensation mapping table, and the third environmental mathematical model is:

[0075] ;

[0076] Among them, Er(t) is the dielectric constant, P(t) is the ambient air pressure information collected by the air pressure sensor, and n d is the refractive index of air, a is the coefficient related to humidity, RH(t) is the ambient humidity information collected by the humidity sensor, and P0 is the standard air pressure;

[0077] The dielectric compensation mapping table includes a plurality of different dielectric constants and compensation information corresponding to each dielectric constant.

[0078] In this embodiment, the control device has a third environment mathematical model and a dielectric compensation mapping table, where n d , a and P0 are all known numbers. Before leaving the factory, a is calculated through experiments, and the third environment mathematical model and dielectric compensation mapping table are constructed and stored in the control device. The control system may include a humidity sensor and an air pressure sensor. The humidity sensor can collect ambient humidity information in the environment, and the air pressure sensor can collect ambient air pressure information in the environment.

[0079] In practical applications, the third environmental mathematical model is to calculate the third dielectric constant Er(t) based on the ambient air pressure information P(t) collected by the air pressure sensor and the ambient humidity information RH(t) collected by the humidity sensor. The dielectric compensation mapping table includes multiple different dielectric constants and compensation information corresponding to each dielectric constant. The compensation information corresponding to the third dielectric constant Er(t), i.e., the first compensation information, can be found from the dielectric compensation mapping table.

[0080] Specifically, the humidity sensor transmits the collected environmental humidity information to the control device, and the control device performs signal processing on the environmental humidity information collected by the humidity sensor to obtain the corresponding environmental humidity value RH(t). The air pressure sensor transmits the collected environmental pressure information to the control device, and the control device performs signal processing on the environmental pressure information collected by the air pressure sensor to obtain the corresponding environmental pressure value P(t). The control device substitutes the environmental humidity value RH(t) and the environmental pressure value P(t) into the third environmental mathematical model, and then calculates the third dielectric constant Er(t), and then finds the compensation information corresponding to the third dielectric constant Er(t) from the dielectric compensation mapping table as the first compensation information, where the first compensation information is the displacement compensation value. The control device uses the first compensation information to compensate the first displacement information, and the displacement obtained after compensation is determined as the actual displacement value of the measured object.

[0081] In this embodiment, humidity compensation is performed by software. A third environmental mathematical model and a dielectric compensation mapping table are pre-stored in the control device. The first compensation information is calculated based on the environmental humidity information and the environmental air pressure information, and then the first displacement information is compensated. In this way, the measurement result of the capacitive sensor can be compensated according to the environmental humidity and air pressure, which can reduce the interference of the environmental humidity and air pressure on the measurement result of the capacitive sensor and improve the displacement measurement accuracy.

[0082] It should be noted that before leaving the factory, the control device needs to pre-store the third environment mathematical model and the dielectric compensation mapping table, that is, before leaving the factory, it needs to calculate a through multiple tests, and then construct the third environment mathematical model. It can be understood that the construction process of the third environment mathematical model is similar to the construction process of the first environment mathematical model. The difference is that the variables that need to be considered in the construction process of the third environment mathematical model include humidity and air pressure, and the specific process will not be repeated here.

[0083] At least one optional environmental sensor includes a humidity sensor, a temperature sensor and an air pressure sensor; the environment and displacement model includes a second environment mathematical model, a third environment mathematical model and a dielectric compensation mapping table; the second environment mathematical model is a second dielectric constant calculated based on the ambient temperature information collected by the temperature sensor and the ambient humidity information collected by the humidity sensor; the third environment mathematical model is a third dielectric constant calculated based on the ambient air pressure information collected by the air pressure sensor and the ambient humidity information collected by the humidity sensor; the dielectric compensation mapping table includes multiple different dielectric constants and compensation information corresponding to each dielectric constant, and the dielectric constant is the average of the second dielectric constant and the second dielectric constant.

[0084] In this embodiment, the control device stores a dielectric compensation mapping table, a second environment mathematical model and a third environment mathematical model, wherein the second environment mathematical model is the same as the second environment mathematical model of the above embodiment, and the third environment mathematical model is the same as the third environment mathematical model of the above embodiment. The second environment mathematical model is: The mathematical model of the third environment is: .

[0085] In actual applications, the humidity sensor transmits the collected ambient humidity information to the control device, and the control device performs signal processing on the ambient humidity information collected by the humidity sensor to obtain the corresponding ambient humidity value RH(t). The temperature sensor transmits the collected ambient temperature information to the control device, and the control device performs signal processing on the ambient temperature information collected by the temperature sensor to obtain the corresponding ambient temperature value T(t). The pressure sensor transmits the collected ambient air pressure information to the control device, and the control device performs signal processing on the ambient air pressure information collected by the pressure sensor to obtain the corresponding ambient air pressure value P(t).

[0086] The control device substitutes the ambient humidity value RH(t) and the ambient temperature value T(t) into the second environmental mathematical model, and then calculates the second dielectric constant Er(t). The control device substitutes the ambient humidity value RH(t) and the ambient air pressure value P(t) into the third environmental mathematical model, and then calculates the third dielectric constant Er(t). The average value of the second dielectric constant Er(t) and the third dielectric constant Er(t) is used as the target dielectric constant, and then the compensation information corresponding to the target dielectric constant is found from the dielectric compensation mapping table as the first compensation information, where the first compensation information is the displacement compensation value. The control device uses the first compensation information to compensate the first displacement information, and the displacement obtained after compensation is determined as the actual displacement value of the measured object.

[0087] In this embodiment, a second environmental mathematical model, a third environmental mathematical model and a dielectric compensation mapping table are pre-stored in the control device. The first compensation information is calculated based on the environmental humidity, temperature and air pressure information, and then the first displacement information is compensated. In this way, the measurement results of the capacitive sensor can be compensated according to the environmental humidity, temperature and air pressure, which can reduce the interference of the environmental humidity, temperature and air pressure on the measurement results of the capacitive sensor and improve the displacement measurement accuracy.

[0088] In other embodiments, the control device may optionally store a dielectric compensation mapping table and the first environment mathematical model, the second environment mathematical model, and the third environment mathematical model that are the same as those in the above embodiment.

[0089] In actual applications, the control device performs signal processing on the ambient humidity information collected by the humidity sensor to obtain the corresponding ambient humidity value RH(t), the control device performs signal processing on the ambient temperature information collected by the temperature sensor to obtain the corresponding ambient temperature value T(t), and the control device performs signal processing on the ambient air pressure information collected by the air pressure sensor to obtain the corresponding ambient air pressure value P(t).

[0090] The control device substitutes the environmental humidity value RH(t) into the first environmental mathematical model to calculate the first compensation information D1, where the first compensation information D1 is the displacement compensation value. The control device substitutes the environmental humidity value RH(t) and the environmental temperature value T(t) into the second environmental mathematical model to calculate the second dielectric constant Er(t); substitutes the environmental humidity value RH(t) and the environmental pressure value P(t) into the third environmental mathematical model to calculate the third dielectric constant Er(t); takes the average value of the second dielectric constant Er(t) and the third dielectric constant Er(t) as the target dielectric constant, and then searches the dielectric compensation mapping table for the compensation information corresponding to the target dielectric constant as the first compensation information D2, where the first compensation information D2 is the displacement compensation value. The control device takes the average value of the first compensation information D1 and the first compensation information D2 as the final displacement compensation value Dv, and uses the displacement compensation value Dv to compensate the first displacement information, and the displacement obtained after compensation is determined as the actual displacement value of the measured object.

[0091] In the above-described embodiment, the control device calculates the final displacement compensation value Dv based on the ambient humidity, temperature and air pressure information, and then compensates the first displacement information. In this way, the effect of compensating the measurement result of the capacitive sensor according to the ambient humidity, temperature and air pressure can be achieved, which can reduce the interference of the ambient humidity, temperature and air pressure on the measurement result of the capacitive sensor and improve the displacement measurement accuracy.

[0092] The sampling frequency of the first displacement information can be f1, and the sampling frequency of the environmental information can be f2; f1>f2.

[0093] In this embodiment, the acquisition frequency of the capacitive sensor is the sampling frequency of the first displacement information, and the acquisition frequency of the environmental sensor is the sampling frequency of the environmental information. Exemplarily, the ratio of the acquisition frequency of the capacitive sensor to the acquisition frequency of the environmental sensor is greater than 10:1. For example, the acquisition frequency of the selected capacitive sensor is 4KHz, and the acquisition frequency of the environmental sensor is 10Hz (i.e., 0.1s / time). The environment in which the control system is located will not change much in 0.1s, and both humidity, temperature and air pressure will be relatively stable in a short time, that is, the interference to the position detected by the capacitive sensor is relatively stable. Therefore, the acquisition frequency of the selected environmental sensor can be relatively small, which is conducive to reducing the signal processing process of the control device and reducing other interference factors from being serially connected to the control device. It is also suitable for application conditions where the environmental humidity changes drastically or for a long time.

[0094] In addition, the compensation frequency of the capacitive sensor can be equal to the sampling frequency of the environmental information, that is, after the control device samples the environmental information once, it compensates the measurement result of the capacitive sensor once, which can reduce the signal processing complexity of the control device; or, the compensation frequency of the capacitive sensor can be equal to the sampling frequency of the first displacement information, that is, after the control device samples the first displacement information once, it uses the first compensation information to compensate the measurement result of the capacitive sensor once, which can improve the measurement accuracy of the capacitive sensor.

[0095] Before obtaining the first compensation information, the method may include: if the change of environmental information exceeds the allowable range of change, obtaining the first compensation information based on the environment and displacement model and at least one environmental information; or, if the change of environmental information does not exceed the allowable range of change, using the compensation information of the previous compensation cycle as the first compensation information.

[0096] In this embodiment, the environmental information is monitored once at a certain interval to compensate the measurement result of the capacitive sensor. An allowable variation range may be set, for example, the allowable variation range is ±1%.

[0097] If the change of the environmental information detected in the current compensation cycle relative to the environmental information in the previous compensation cycle exceeds the allowable change range, new first compensation information is calculated based on the environment and displacement model and the current environmental information and the first displacement information is compensated.

[0098] If the change in environmental information detected in the current compensation cycle relative to the environmental information in the previous compensation cycle is within the allowable range of change, there is no need to calculate new first compensation information based on the environment and displacement model and the current environmental information. Instead, the first compensation information of the previous compensation cycle is used as the first compensation information of the current compensation cycle and the first displacement information is compensated. In other words, every time the environmental information changes within a certain range, new first compensation information is calculated and the position detected by the capacitive sensor is compensated once. Therefore, it is helpful to reduce the complexity of the signal processing process of the control device, and is suitable for application conditions where the environmental humidity changes drastically or for a long time. A compensation cycle mentioned here refers to such as Figure 2 The compensation process shown in step 210 to step 230 is performed. The first compensation information in the compensation process may be the first compensation information directly obtained in the current compensation cycle. The first compensation information in the compensation process may also be the same as the first compensation information in the previous compensation cycle.

[0099] Optionally, after compensating the first displacement information, the method further includes: filtering and denoising the displacement information obtained after compensation.

[0100] In this embodiment, after the first compensation information is used to compensate the first displacement information, the displacement information obtained after compensation may be filtered and denoised to further reduce the influence of external interference on the displacement measurement result and improve the measurement accuracy of the capacitive sensor.

[0101] Optionally, after compensating the first displacement information, the method includes: calculating a displacement offset value according to the displacement information obtained after compensation and target displacement information of the measured object, so that the displacement driver drives the measured object according to the displacement offset value.

[0102] In this embodiment, a PID closed-loop control loop can be used to perform humidity compensation on the capacitive sensor according to the monitoring data of the environmental sensor. The closed-loop control process can be adjusted in real time according to actual environmental changes. Therefore, when the environment, such as humidity, changes drastically or for a long time, the measurement results of the capacitive sensor can be adjusted in real time according to the actual environmental changes, thereby improving the adaptability and robustness of the control system.

[0103] Figure 5 is a schematic diagram of another control system provided by an embodiment of the present invention, and Figure 1 The difference is that Figure 5 The control system 100 also includes a displacement driver 104. The specific process is as follows:

[0104] 1) The control system 100 receives a control instruction from a host computer, a server, or an external device, and the control instruction carries the target displacement information Sin of the measurement object 10;

[0105] 2) The displacement driver 104 drives the measurement object 10 to move according to the target displacement information Sin;

[0106] 3) The capacitive sensor 101 collects displacement information of the driving measurement object 10 to obtain first displacement information, and transmits it to the control device 103;

[0107] 4) The environmental sensor 102 collects environmental information of the environment and transmits it to the control device 103;

[0108] 5) The control device 103 calculates the displacement measurement value of the measurement object 10 according to the first displacement information, and obtains the first compensation information according to the environmental information and the environment and displacement model. The control device 103 calculates the displacement compensation value according to the first compensation information;

[0109] 6) The control device 103 uses the displacement compensation value to compensate the displacement measurement value, and the displacement amount obtained after compensation is determined as the displacement correction value Sx of the measurement object 10;

[0110] 7) The control device 103 or its subsequent signal processing circuit can compare the displacement correction value Sx and the target displacement information Sin to calculate the displacement offset value Ser;

[0111] 8) The displacement driver 104 drives the measurement object 10 to move according to the displacement offset value Ser.

[0112] It should be noted that the control system 100 may output a displacement signal Sout after each compensation; or the control system 100 may output a displacement signal Sout after multiple compensations. The displacement signal Sout output by the control system 100 carries a compensated displacement value, which can be regarded as the actual displacement value of the measurement object 10.

[0113] In this embodiment, the control system is applied to the PID closed-loop control loop to compensate the measurement result of the capacitive sensor. The PID closed-loop control loop is a commonly used automatic control system, and the controlled quantity (i.e., the output signal) can be fed back to the control system in real time, thereby forming a closed control loop. The PID closed-loop control loop has the advantages of good stability, fast response speed, and high control accuracy. The feedback link in the PID closed-loop control loop can realize accurate feedback of position accuracy, so that the control error of the movement of the measured object 10 is as small as possible, thereby making the movement accuracy of the device higher and the stability better, making the distance of the measured object detected by the capacitive sensor closer to the actual situation, eliminating some interference factors of environmental information, and making the measured position accuracy higher and the stability better.

[0114] Optionally obtaining at least one type of environmental information includes: predicting the environmental information based on historical environmental data collected by at least one environmental sensor in the environment where the capacitive sensor is located.

[0115] In this embodiment, the environmental sensor can collect environmental information in real time, and the control device can calculate the first compensation information based on the current environmental information. Historical environmental data is stored in the environmental sensor or the control device, and the control device can obtain predicted environmental information based on the existing historical environmental data, and calculate the first compensation information based on the predicted environmental information. Specifically, a software algorithm such as a neural network algorithm or function fitting is used to predict the changing trend of environmental information based on historical data and real-time data, and compensate in advance based on the predicted results. The training samples of the software algorithm can select environmental data from the past month, and the training goal is to minimize the prediction error.

[0116] Generally, the overall environmental humidity (RH) of high-precision measurement equipment or semiconductor equipment is related to many factors such as temperature (T), heat load (Q), air exchange rate (P), air handling system (HVAC), etc. There are large differences in the environment of different equipment. It can be found that the changes in the internal environment (such as humidity) of the same equipment are regular and inherited. Take the impact of air humidity on equipment as an example. Figure 6 It is a schematic diagram of the humidity changes in a device.

[0117] according to Figure 6 It can be seen that the ambient humidity (RH) of the device changes periodically with time (t), so the humidity change of the device can be predicted by multiple sets of ambient humidity test data. The neural network algorithm can learn patterns and features from the big data of long-term detection of the whole machine environment, and output the current ambient humidity according to various complex environmental conditions, among which the whole machine ambient temperature (T), heat load (Q), air exchange rate (P), air handling system (HVAC) and other factors are input signals received by each neuron (these input signals are related to time (t)). After weighted summation and activation function processing, the output signal of air humidity RH is generated, that is, the predicted ambient humidity value. Usually, the neural network algorithm needs to be continuously trained and the network parameters (weight λ and bias Δ) are adjusted so that the humidity prediction model based on the neural network algorithm can more accurately predict the output signal. Obviously, if the control device stores historical ambient humidity data, then even if there is no humidity sensor, the humidity prediction model can also be used in this embodiment to realize humidity compensation for the capacitive sensor.

[0118] It should be noted that environmental information is obtained by using historical environmental data prediction. This method is applicable to batches of the same type of equipment, that is, the equipment environment is the same, the process is the same, and the environmental changes are regular, or closely related to related processes. Then, the environmental signal is predicted by a neural network algorithm, and the capacitive sensor is positionally compensated. Taking the environmental signal including the environmental humidity signal as an example, the method of using historical environmental humidity data to predict the environmental humidity information can save the humidity sensor in the control system. Then the control device does not need to store the signal processing and algorithm of the humidity sensor, which greatly reduces the hardware cost. At the same time, the accuracy and stability of the capacitive sensor signal can be achieved, and the position accuracy and performance of the equipment can be improved.

[0119] Based on the same inventive concept, an embodiment of the present invention provides a control device, which can execute the control method described in any of the above embodiments. The control device is integrated in the control system described in any of the above embodiments. Figure 7 is a schematic diagram of a control device provided by an embodiment of the present invention, such as Figure 7 The control device provided in the embodiment of the present invention shown includes: a displacement measurement module 310, an environment sampling module 320 and a compensation module 330; the displacement measurement module 310 is used to obtain first displacement information of the measurement object through a capacitive sensor; the environment sampling module 320 is used to obtain at least one environmental information through at least one environmental sensor in the same environment as the capacitive sensor; the compensation module 330 is used to obtain first compensation information and compensate for the first displacement information based on an environment and displacement model and at least one environmental information.

[0120] The control device provided in the embodiment of the present invention can execute the control method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0121] refer to Figure 1 As shown is a control system 100 provided by an embodiment of the present invention, the control system 100 includes: a capacitive sensor 101, at least one environmental sensor 102 in the same environment as the capacitive sensor 101, and a control device 103 as described in any of the above embodiments; the control device 103 is electrically connected to the capacitive sensor 101 and the at least one environmental sensor 102, respectively.

[0122] refer to Figure 5 Another control system 100 provided by an embodiment of the present invention is shown, and the control system 100 also includes: a displacement driver 104, which is electrically connected to a control device 103; the control device 103 is used to calculate a displacement offset value Ser based on the displacement information Sx obtained after compensation and the target displacement information Sin of the measurement object 10; the displacement driver 104 is used to drive the measurement object 10 according to the displacement offset value Ser.

[0123] The control system provided by the embodiment of the present invention can not only improve the position detection accuracy of the capacitive sensor, but also be applicable to the influence of other factors on the position accuracy of the capacitive sensor, such as temperature change, electromagnetic interference, etc., so that the capacitive sensor can maintain a high-precision working state in various environments, with higher position accuracy, stronger environmental adaptability and lower implementation cost. The control system can be widely used in precision motion platforms, optical platforms and other fields that require high-precision position detection, especially in high-tech manufacturing industries such as semiconductor manufacturing, microelectronics processes, precision machining, etc., where the high-precision position detection capability of the capacitive sensor is crucial. In the present invention, the control system can effectively improve the position accuracy of the capacitive sensor and reduce the influence of factors such as environmental humidity on the position detection of the capacitive sensor by using a closed-loop control method for compensation of environmental information (humidity, temperature, air pressure, etc.), and has the characteristics of fast response and high precision, thereby improving production efficiency and product quality. At the same time, since the control system does not require additional sensors or complex calculation processes, it has low implementation costs, is easy to implement, and has high practical value and broad market prospects.

[0124] The optional control system also includes a preamplifier, demodulator and A / D converter. Figure 8 is a schematic diagram of another control system provided by an embodiment of the present invention, such as Figure 8 The control system 100 shown also includes a preamplifier 105, a demodulator 106 and an A / D converter 107 which are electrically connected in sequence, and the preamplifier 105, the demodulator 106 and the A / D converter 107 are electrically connected between the capacitive sensor 101 and the control device 103. The displacement signal output by the control system 100 is transmitted to the host computer 200.

[0125] Specifically, the first displacement information (here, it refers to the capacitance analog quantity, which can also be converted into a voltage signal) of the measurement object 10 collected by the capacitance sensor 101 is sequentially converted into a digital signal through the preamplifier 105, the demodulator 106 and the A / D converter 107, and the digital signal is sent to the control device 103. Here, the environmental sensor 102 can be a humidity sensor, and the humidity sensor synchronously collects the change of environmental humidity. The environmental humidity signal can be converted into a digital signal by the A / D converter 107 and then sent to the control device 103. The control device 103 includes a microprocessor, and the microprocessor receives the first displacement information transmitted by the capacitance sensor 101 and the environmental humidity information transmitted by the humidity sensor. The microprocessor calculates the corresponding displacement compensation value through the humidity compensation mathematical model, that is, the first environmental mathematical model; the microprocessor converts the first displacement information into a displacement measurement value; the microprocessor adds the displacement compensation value and the displacement measurement value, and then processes the data by filtering to obtain the final displacement actual value, and outputs the displacement actual value to the host computer 200.

[0126] Fig. 9 is a schematic diagram of a motion control mechanism provided by an embodiment of the present invention, such as Fig. 9 As shown, the control motion mechanism includes a capacitive sensor 101 and a rotating motion plate 10, the rotating motion plate 10 is the measurement object, and the capacitive sensor 101 is used to detect the distance of the detection surface relative to the rotating motion plate 10. The control motion mechanism also includes a flexible hinge 141, and the flexible hinge 141 is a bearing mechanism with high rotational stiffness, no friction, and can realize rotation. The control motion mechanism also includes two groups of tension springs, namely, a tension spring 142 and a tension spring 143, and the two groups of tension springs provide preload force for the piezoelectric actuator 144, and can improve the dynamic performance of the control motion mechanism. The control motion mechanism also includes a piezoelectric actuator 144, and the displacement driver includes a piezoelectric actuator 144, and the piezoelectric actuator 144 is a motion actuator with high resolution, high rigidity, high response frequency, and high control bandwidth. The rotating motion plate 10 is fixedly connected to the flexible hinge 141. The working process of the control motion mechanism is as follows: the piezoelectric actuator 144 applies a downward or upward force on one side (the right side in the figure) of the rotation motion plate 10, and the distance of the other side (the left side in the figure) of the rotation motion plate 10 relative to the capacitive sensor 101 changes through the guidance of the flexible hinge 141, and the capacitive sensor 101 can detect the distance S between the surface of the rotation motion plate 10 and the detection surface of the capacitive sensor 101. The control motion mechanism is applied in a control system.

[0127] The control system provided by the embodiment of the present invention can execute the control method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0128] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0129] 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 displacement control method for a motion platform, characterized in that: include: Acquiring first displacement information of the measurement object through a capacitive sensor; Acquiring at least one type of environmental information through at least one environmental sensor in the same environment as the capacitive sensor; Obtaining first compensation information and compensating the first displacement information according to the environment and displacement model and the at least one environmental information; The at least one environmental sensor comprises a humidity sensor; The at least one environmental sensor further comprises at least one of a temperature sensor and an air pressure sensor; The environment and displacement model includes a second environment mathematical model, a third environment mathematical model and a dielectric compensation mapping table; The second environmental mathematical model is to calculate the second dielectric constant based on the environmental temperature information collected by the temperature sensor and the environmental humidity information collected by the humidity sensor; The third environmental mathematical model is a third dielectric constant calculated based on the environmental air pressure information collected by the air pressure sensor and the environmental humidity information collected by the humidity sensor; The dielectric compensation mapping table includes multiple different dielectric constants and compensation information corresponding to each dielectric constant; the dielectric constant is the second dielectric constant, or the dielectric constant is the third dielectric constant, or the dielectric constant is the average of the second dielectric constant and the third dielectric constant.

2. The displacement control method according to claim 1, characterized in that: The at least one environmental sensor includes a humidity sensor and a temperature sensor; The environment and displacement model includes a second environment mathematical model and a dielectric compensation mapping table, and the second environment mathematical model is: Er(t)=1+n*R*T(t)*(n d −1+a*RH(t)) / (P0*V)? Wherein, Er(t) is the dielectric constant, n, R and V are coefficients related to temperature and gas, T(t) is the ambient temperature information collected by the temperature sensor, n d is the refractive index of air, a is a coefficient related to humidity, RH(t) is the ambient humidity information collected by the humidity sensor, and P0 is the standard air pressure; The dielectric compensation mapping table includes a plurality of different dielectric constants and compensation information corresponding to each of the dielectric constants.

3. The displacement control method according to claim 1, characterized in that: The at least one environmental sensor includes a humidity sensor and an air pressure sensor; The environment and displacement model includes a third environment mathematical model and a dielectric compensation mapping table, and the third environment mathematical model is: Er(t)=1+P(t)*(n d −1+a*RH(t)) / P0: Wherein, Er(t) is the dielectric constant, P(t) is the ambient air pressure information collected by the air pressure sensor, and n d is the refractive index of air, a is a coefficient related to humidity, RH(t) is the ambient humidity information collected by the humidity sensor, and P0 is the standard air pressure; The dielectric compensation mapping table includes a plurality of different dielectric constants and compensation information corresponding to each of the dielectric constants.

4. The displacement control method according to claim 1, characterized in that: The sampling frequency of the first displacement information is f1, and the sampling frequency of the environmental information is f2; f1>f2.

5. The displacement control method according to claim 1, characterized in that: Before obtaining the first compensation information, including: If the change of the environmental information exceeds the allowable change range, obtaining the first compensation information according to the environment and displacement model and the at least one environmental information; Alternatively, if the change of the environmental information does not exceed the allowable change range, the compensation information of the previous compensation cycle is used as the first compensation information.

6. The displacement control method according to claim 1, characterized in that: After compensating the first displacement information, the method further comprises: The displacement information obtained after compensation is filtered and denoised.

7. The displacement control method according to claim 1, characterized in that: After compensating the first displacement information, the method further comprises: A displacement offset value is calculated based on the displacement information obtained after compensation and the target displacement information of the measured object, so that the displacement driver drives the measured object according to the displacement offset value.

8. The displacement control method according to claim 1, characterized in that: Obtain at least one type of environmental information, including: The environmental information is predicted based on historical environmental data collected by the at least one environmental sensor in the environment where the capacitive sensor is located.

9. A displacement control device for a motion platform, characterized in that: include: A displacement measurement module, used for acquiring first displacement information of a measurement object through a capacitive sensor; An environment sampling module, used to obtain at least one kind of environment information through at least one environment sensor in the same environment as the capacitive sensor; A compensation module, configured to obtain first compensation information and compensate the first displacement information according to the environment and displacement model and the at least one environmental information; The at least one environmental sensor comprises a humidity sensor; The at least one environmental sensor further comprises at least one of a temperature sensor and an air pressure sensor; The environment and displacement model includes a second environment mathematical model, a third environment mathematical model and a dielectric compensation mapping table; The second environmental mathematical model is to calculate the second dielectric constant based on the environmental temperature information collected by the temperature sensor and the environmental humidity information collected by the humidity sensor; The third environmental mathematical model is a third dielectric constant calculated based on the environmental air pressure information collected by the air pressure sensor and the environmental humidity information collected by the humidity sensor; The dielectric compensation mapping table includes multiple different dielectric constants and compensation information corresponding to each dielectric constant; the dielectric constant is the second dielectric constant, or the dielectric constant is the third dielectric constant, or the dielectric constant is the average of the second dielectric constant and the third dielectric constant.

10. A displacement control system for a motion platform, characterized in that: include: A capacitive sensor, at least one environmental sensor in the same environment as the capacitive sensor, and a displacement control device as claimed in claim 9; The displacement control device is electrically connected to the capacitive sensor and the at least one environmental sensor respectively.

11. The displacement control system according to claim 10, characterized in that: Also includes: a displacement driver, the displacement driver being electrically connected to the displacement control device; The displacement control device is used to calculate the displacement offset value according to the displacement information obtained after compensation and the target displacement information of the measured object; The displacement driver is used to drive the measurement object according to the displacement offset value.

Images