A high-precision linear displacement and angular displacement system

Abstract

The application relates to the technical field of sensors, in particular to a high-precision linear displacement and angular displacement system which comprises a metal object moving target, a detection device, a PCB circuit board and a planar coil, the planar coil is printed on the PCB circuit board, the planar coil comprises a transmitting coil and a receiving coil, the transmitting coil and the receiving coil are connected with the detection device, the transmitting coil comprises a transmitting coil one and a transmitting coil two, the receiving coil comprises an A-group receiving coil one and an A-group receiving coil two and a B-group receiving coil one and a B-group receiving coil two, the application is resistant to temperature drift, is very small in influence on environmental temperature change, is in time in signal response, is very suitable for dynamic signal detection, is stronger in anti-interference, is resistant to severe environment, is convenient for on-site debugging and software upgrading, is modularized in hardware, and is more suitable for hardware module replacement and upgrading.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a high-precision linear displacement and angular displacement system. BACKGROUND

[0002] Angular displacement sensors and linear displacement sensors can detect the rotational angular displacement and linear displacement of a target object. They are mainly used in flow meters, industrial machine tools, the robotics industry, and the industrial Internet of Things industry.

[0003] Current angular displacement and linear displacement sensors used in industry are mainly of the grating type, but gratings have the following disadvantages:

[0004] Gratings directly reflect changes in strain and temperature coupling, and temperature compensation must be performed when measuring strain; gratings are more suitable for measuring static or quasi-static physical quantities based on strain and temperature changes (such as strain, stress, temperature, displacement, cable force, pressure, etc.), and are not suitable for measuring dynamic signals (such as vibration signals) and humidity, wind speed, and other signals;

[0005] Grating sensors and demodulation equipment are not convenient to debug on site; in order to reduce fiber signal loss and avoid air or dust entering the flange, which causes the laser to be unable to transmit, an optical fiber fusion splicing method is generally used to connect the sensor, which cannot meet the need to frequently replace the sensor during the on-site debugging stage.

[0006] Existing demodulation equipment is often composed of industrial control mechanisms, and the working temperature and humidity range, shock resistance, and corrosion resistance are limited, and it is not resistant to harsh environments. Angular displacement sensors based on planar coils have low angular displacement accuracy and cannot be used in the industrial machine tool, robotics, and industrial Internet of Things industries, but can only be used in flow meter products with low angular displacement accuracy, which has a large limitation.

[0007] Based on the above reasons, the present application designs a high-precision linear displacement and angular displacement system that combines linear displacement and angular displacement detection, solves the shortcomings of grating sensors, differentially detects the output signals of the inductive coil, has high sensitivity, and can be applied to working environments with low power consumption and micro signals. SUMMARY

[0008] The purpose of the present application is to overcome the shortcomings of the prior art and provide a high-precision linear displacement and angular displacement system that combines linear displacement and angular displacement detection, solves the shortcomings of grating sensors, differentially detects the output signals of the inductive coil, has high sensitivity, and can be applied to working environments with low power consumption and micro signals.

[0009] In order to achieve the above object, the present application provides a high-precision linear displacement and angular displacement system, which comprises a metal object moving target, a detection device, a PCB circuit board and a planar coil, the planar coil is printed on the PCB circuit board, the planar coil comprises a transmitting coil and a receiving coil, the transmitting coil and the receiving coil are connected with the detection device, the detection device comprises a signal driving circuit, a signal receiving circuit, a detection circuit, a 16-bit bit AD sampling circuit, a constant current source circuit with adjustable current size, an interval resistance adjustable circuit, a feedback adjustment circuit, a nanosecond high-precision timer and a shock starting circuit with adjustable amplitude, the transmitting coil comprises a transmitting coil one and a transmitting coil two, the receiving coil comprises a group A receiving coil one and a group A receiving coil two and a group B receiving coil one and a group B receiving coil two, the metal object moving target is placed above the transmitting coil and the receiving coil in a non-contact manner, the metal object moving target is parallel to the PCB circuit board, and the excitation signal on the transmitting coil maintains a certain proportional interval characteristic and reaches a precise value through calibration.

[0010] The feedback adjustment circuit adjusts the constant current source current size, the shock amplitude of the shock starting circuit, the interval resistance value size, the pulse amplitude and the pulse width, and the shock amplitude, the interval resistance, the constant current source size, the pulse amplitude and the pulse width are continuously adjustable within the interval range.

[0011] The receiving coil is distributed in a periodic parabola y=x² or a triangular wave on the PCB circuit board.

[0012] The size of the transmitting coil on the PCB circuit board maintains a characteristic formula: a=(Nb)², N is a natural number greater than or equal to 1.

[0013] The metal object moving target is rectangular, semicircular or arc-shaped.

[0014] The number of transmitting coils and receiving coils used is related to the space available size of the PCB circuit board, the engineering measurement linear displacement and the angular displacement precision.

[0015] The excitation signals of the signal driving circuit driving the transmitting coil are respectively:

[0016] Resonant LC oscillation signal;

[0017] Pulse signal ≤20 nanoseconds;

[0018] e function exponential decay signal;

[0019] When the transmitting coil one and the transmitting coil two are two independent planar coils, the two transmitting coils maintain:

[0020] If the excitation signal selects the resonant LC oscillation signal, the resonant LC oscillation signals of the transmitting coil one and the transmitting coil two maintain the same frequency and the same phase, and the oscillation amplitude maintains a certain proportion;

[0021] If the excitation signal is selected as a pulse signal with a pulse width of ≤20 nanoseconds, the pulse signals of the transmitting coil one and the transmitting coil two are kept in synchronization, i.e., transmitted at the same time, with the same pulse width and the pulse amplitudes maintaining a certain ratio.

[0022] If the excitation signal is selected as an e-function exponential decay signal, the initial currents of the decay signals of the transmitting coil one and the transmitting coil two maintain a certain ratio, and the decay constants are equal.

[0023] The receiving coil and the transmitting coil are in the same PCB circuit board plane and distributed within the geometric range of the transmitting coil. The receiving coil senses the change of the magnetic flux caused by the change of the excitation signal current on the transmitting coil to generate an induced electromotive force. The receiving coil is connected with a signal receiving circuit, and a detection device detects the change of the induced electromotive force of the receiving coil.

[0024] The transmitting coil is geometrically symmetrical, and the magnetic field distribution in the transmitting coil ensures the symmetry. The receiving coil is distributed in the transmitting coil and located in the same PCB circuit board plane. The receiving coil ensures the symmetry, so that the induced electromotive force of at least one receiving coil in the receiving coil is zero when the metal object is absent.

[0025] The receiving coil is divided into group A and group B, and each 2 paths form a receiving group. The receiving coils on each group are geometrically symmetrical. The receiving coil wiring ensures the symmetry, and each receiving coil in each group is divided into 2 sub-coils. The same name ends and the different name ends of the 2 sub-coils are connected, so that the induced electromotive force of at least one receiving coil in each group is zero when the metal object is absent.

[0026] When the transmitting coil is two paths, in the absence of the moving target of the metal object, a feedback adjustment circuit is used to calibrate the electrical parameters of the excitation signal of the transmitting coil. The feedback adjustment circuit adjusts the electrical parameters of the excitation signal of the transmitting coil according to the change of the electrical parameters of the induced signal of the receiving coil, so that the induced electromotive force pressure difference of the receiving coil and the pressure difference of the sub-coils of each receiving coil are equal. Specifically:

[0027] Resonant LC oscillation signal: the feedback circuit adjusts the oscillation amplitude of the LC oscillation circuit;

[0028] ≤20 nanosecond pulse signal: the feedback circuit adjusts the amplitude and width of the pulse signal;

[0029] e-function exponential decay signal: the feedback circuit adjusts the initial current size and the decay constant, so that the decay constants of the two transmitting coils are equal;

[0030] When the transmitting coil is one path, only the pulse amplitude, the constant current source size, and the oscillation amplitude of the LC oscillation circuit need to be adjusted.

[0031] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coils are distributed in the transmitting coil, the receiving coils are distributed in a triangular wave geometry, and the two receiving coils in each group are distributed with a 90-degree phase difference. The receiving coils are distributed in a geometric symmetry.

[0032] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coils are distributed in the transmitting coil, the receiving coils are distributed in a triangular wave geometry, and the two receiving coils in each group are distributed with a 90-degree phase difference. The receiving coils are distributed in a geometric symmetry.

[0033] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coils are distributed in the transmitting coil, the receiving coils are distributed in a triangular wave geometry, and the two receiving coils in each group are distributed with a 90-degree phase difference. The receiving coils are distributed in a geometric symmetry.

[0034] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coils are distributed in the transmitting coil, the receiving coils are distributed in a triangular wave geometry, and the two receiving coils in each group are distributed with a 90-degree phase difference. The receiving coils are distributed in a geometric symmetry.

[0035] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coils are distributed in the transmitting coil, the receiving coils are distributed in a triangular wave geometry, and the two receiving coils in each group are distributed with a 90-degree phase difference. The receiving coils are distributed in a geometric symmetry.

[0036] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coils are distributed in the transmitting coil, the receiving coils are distributed in a triangular wave geometry, and the two receiving coils in each group are distributed with a 90-degree phase difference. The receiving coils are distributed in a geometric symmetry.

[0037] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coils are distributed in the transmitting coil, the receiving coils are distributed in a triangular wave geometry, and the two receiving coils in each group are distributed with a 90-degree phase difference. The receiving coils are distributed in a geometric symmetry.

[0038] The interval of 0.4-0.5 can be adjusted to zero induced electromotive force and zero pressure difference of at least one receiving coil in each group by a feedback adjustment circuit.

[0039] When the system is an angular displacement system, if two transmitting coils are used, the transmitting coil one and the transmitting coil two are circular, the transmitting coil one and the transmitting coil two are distributed inside and outside, the transmitting coil one surrounds the transmitting coil two, and are distributed in concentric circles;

[0040] The geometric size radius ratio of the transmitting coil one and the transmitting coil two is 0.9;

[0041] When a resonant LC oscillation signal is used as an excitation signal, the amplitude ratio of the LC oscillation of the transmitting coil one and the transmitting coil two is between 0.7 and 0.8;

[0042] When a pulse signal ≤20 nanoseconds is used as an excitation signal, the amplitude ratio of the pulse of the transmitting coil one and the transmitting coil two is between 0.7 and 0.8, and the pulse width is the same;

[0043] When an e function exponential decay signal is used as an excitation signal, the size ratio of the initial constant current source current of the transmitting coil one and the transmitting coil two is between 0.7 and 0.8, and the decay constant is equal;

[0044] The interval of 0.7-0.8 can be adjusted to at least one receiving coil induced electromotive force of 0 and a pressure difference of 0 in each group by a feedback adjustment circuit; The wire and current direction of the transmitting coil one and the transmitting coil two ensure that the magnetic flux of the transmitting coil one and the transmitting coil two passes through the PCB circuit board plane in opposite directions;

[0045] When the system is a linear displacement system, if one transmitting coil is used, the transmitting coil is rectangular, and the geometric size length a and width b of the transmitting coil ensure the constraint condition:

[0046] a=(Nb)², N is a natural number ≥1;

[0047] The shortest vertical distance between the transmitting coil width b and the receiving coil distributed in the transmitting coil is ≥b / 2, if b / 2 is less than 5mm, then it is at least 5mm, and increases in proportion to the square root of the number of ampere turns of the transmitting coil; The receiving coil is distributed in the transmitting coil with a 90-degree phase difference parabolic periodic distribution, or a 90-degree phase difference triangular wave periodic distribution; If the receiving coil is distributed in the transmitting coil with a triangular wave, the geometric size length a and width b of the transmitting coil need to ensure the constraint condition that the length a ≥10b;

[0048] When the system is an angular displacement system, if one transmitting coil is used, the transmitting coil is circular, and the receiving coil is distributed in the transmitting coil, and the excitation signal of the transmitting coil is:

[0049] When the excitation signal of one transmitting coil is a resonant LC oscillation signal, it can be sent periodically, and the time width of each resonant LC oscillation signal is between 10 microseconds and 5000 microseconds, or it is continuously sent;

[0050] When the excitation signal of one transmitting coil is an e-function exponential decay signal, it must be sent periodically, and the time width of the e-function exponential decay signal is between 1 microsecond and 1000 microseconds, and when the internal receiving coil is not more than 4, it is symmetrically distributed around the center point; when the internal receiving coil is one, it must be spindle type distribution.

[0051] When the excitation signal of one transmitting coil is a pulse signal of ≤20 nanoseconds, the pulse signal on the transmitting coil is a periodic transmission signal, and the time width of each pulse signal is not more than 20 nanoseconds, and the amplitude can be configured and adjusted through a feedback circuit. When the internal receiving coil is one and must be spindle type distribution, a voltage holding circuit must be added in the detection device, and the voltage needs to be maintained for at least 16 AD sampling clocks.

[0052] Compared with the prior art, the present application has the following beneficial effects:

[0053] 1. Anti-temperature drift, very small affected by environmental temperature change;

[0054] 2. Signal response is timely, and is very suitable for dynamic signal detection;

[0055] 3. Stronger anti-interference, resistant to harsh environment;

[0056] 4. Convenient on-site debugging and software upgrade;

[0057] 5. Hardware modularization, more suitable for hardware module replacement and upgrade.

[0058] The output signal of the induction coil is differentially detected, and the sensitivity is high, so it can be applied to the working environment of micro-power consumption and micro-signal. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 It is a schematic diagram of the line displacement device of the present application.

[0060] Figure 2 It is a schematic diagram of the angle displacement device of the present application.

[0061] Figure 3 It is a schematic diagram of the receiving coil device of group A and group B of the present application.

[0062] Figure 4 It is a schematic diagram of the periodic parabolic coil loop with a phase difference of 90 degrees of the present application.

[0063] Figure 5 It is a schematic diagram of the periodic parabolic PCB of the present application.

[0064] BRIEF DESCRIPTION OF DRAWINGS

[0065] 1 is a transmitting coil one, 2 is a transmitting coil two, 3 is a receiving coil one of group A, 4 is a receiving coil two of group A, 5 is a detection device, 6 is a metal object moving target, 7 is a receiving coil one of group B, 8 is a receiving coil two of group B, 9 is a junction of homonymic end and heteronymic end of a sub-coil, 10 is a parabola y2 curve, 11 is a parabola y1 curve, 102, 107, 104, 109 are periodic parabola PCB curves constituting a receiving coil two loop of group A respectively, 101, 108, 105, 106, 103, 110 are periodic parabola PCB curves constituting a receiving coil one loop of group A respectively. EMBODIMENT

[0066] The application will be further described in conjunction with the drawings.

[0067] Reference Figures 1 to 5 The application provides a high-precision linear displacement and angular displacement system, comprising a metal object moving target 6, a detection device 5, a PCB circuit board and a planar coil, the planar coil is printed on the PCB circuit board, the planar coil comprises a transmitting coil and a receiving coil, the transmitting coil and the receiving coil are connected with the detection device 5, the detection device 5 comprises a signal driving circuit, a signal receiving circuit, a detection circuit, a 16-bit bit AD sampling circuit, a constant current source circuit with adjustable current size, an interval resistance adjustable circuit, a feedback adjustment circuit, a nanosecond-level high-precision timer and a shock starting circuit with adjustable amplitude, the transmitting coil comprises a transmitting coil one 1 and a transmitting coil two 2, the receiving coil comprises a receiving coil one 3 of group A, a receiving coil two 4 of group A, a receiving coil one 7 of group B and a receiving coil two 8 of group B, the metal object moving target 6 is placed non-contact above the transmitting coil and the receiving coil, the metal object moving target 6 is parallel to the PCB circuit board, and the excitation signal on the transmitting coil maintains a specific proportional interval characteristic and reaches a precise value through calibration.

[0068] The feedback adjustment circuit adjusts the constant current source current size, the shock amplitude of the shock starting circuit, the interval resistance value size, the pulse amplitude and the pulse width, and the shock amplitude, the interval resistance, the constant current source size, the pulse amplitude and the pulse width are continuously adjustable within an interval range.

[0069] The receiving coil is distributed on the PCB circuit board in a periodic parabola y=x² or a triangular wave.

[0070] The size of the transmitting coil on the PCB circuit board maintains a characteristic formula that a=(Nb)², N is a natural number greater than or equal to 1.

[0071] The metal object moving target 6 is rectangular, semicircular or arc-shaped.

[0072] The number of sending coils and receiving coils used is related to the available size of the PCB circuit board space, the engineering measurement linear displacement, and the angular displacement accuracy.

[0073] The excitation signals for driving the sending coils by the signal driving circuit are respectively:

[0074] a resonant LC oscillation signal;

[0075] a pulse signal with a width of ≤20 nanoseconds;

[0076] an e-function exponential decay signal.

[0077] When the sending coil one 1 and the sending coil two 2 are two independent planar coils, the two sending coils maintain:

[0078] If the excitation signal is selected to be a resonant LC oscillation signal, the resonant LC oscillation signals of the sending coil one 1 and the sending coil two 2 maintain the same frequency and phase, and the oscillation amplitude maintains a certain proportion.

[0079] If the excitation signal is selected to be a pulse signal with a width of ≤20 nanoseconds, the pulse signals of the sending coil one 1 and the sending coil two 2 maintain synchronization, i.e., are sent at the same time, have the same pulse width, and the pulse amplitudes maintain a certain proportion.

[0080] If the excitation signal is selected to be an e-function exponential decay signal, the initial currents of the decay signals of the sending coil one 1 and the sending coil two 2 maintain a certain proportion, and the decay constants are equal.

[0081] The receiving coils and the sending coils are in the same PCB circuit board plane, and the receiving coils are distributed within the geometric range of the sending coils. The receiving coils generate an induced electromotive force due to the change in the magnetic flux caused by the change in the excitation signal current on the sending coils. The receiving coils are connected to a signal receiving circuit, and a detection device 5 detects the change in the induced electromotive force of the receiving coils.

[0082] The sending coils are geometrically symmetrical, and the magnetic field distribution within the sending coils ensures the symmetry. The receiving coils are distributed within the sending coils and are in the same PCB circuit board plane. The receiving coils ensure the symmetry, so that the induced electromotive force of at least one receiving coil in the receiving coils is zero when no metal object exists.

[0083] The receiving coils are divided into group A and group B, with each 2 paths being a receiving group. The receiving coils on each group are geometrically symmetrical. The receiving coil traces ensure the symmetry, and each receiving coil in each group is divided into 2 sub-coils, with the same-named ends of the 2 sub-coils being connected. This makes the induced electromotive force of at least one receiving coil in each group be zero when no metal object exists.

[0084] When the transmitting coil is two-way, in the absence of the metal object moving target 6, the feedback adjustment circuit is used to calibrate the electrical parameters of the excitation signal of the transmitting coil, and the feedback adjustment circuit adjusts the electrical parameters of the excitation signal of the transmitting coil according to the change of the electrical parameters of the induced signal of the receiving coil, so that the induced electromotive force pressure difference of the receiving coil and the pressure difference of each sub-coil of the receiving coil are equal, and the specific method is as follows:

[0085] Resonant LC oscillation signal: the feedback circuit adjusts the oscillation amplitude of the LC oscillation circuit;

[0086] Pulse signal ≤20 nanoseconds: the feedback circuit adjusts the amplitude and width of the pulse signal;

[0087] Exponential decay signal e function: the feedback circuit adjusts the initial current size and decay constant, so that the decay constants of the two transmitting coils are equal;

[0088] When the transmitting coil is one-way, only the pulse amplitude, the oscillation amplitude of the LC oscillation circuit and the size of the constant current source need to be adjusted.

[0089] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coil is distributed in the transmitting coil, the receiving coil is triangular wave geometric size distribution, and the two-way receiving coil in each group is distributed with a phase difference of 90 degrees, and the receiving coil distribution maintains its own geometric symmetry; when the system is an angular displacement system, the transmitting coil is circular, the receiving coil is distributed in the transmitting coil, the receiving coil is chord arc geometric size distribution, and the receiving coil is distributed symmetrically around the center of the transmitting coil; the receiving coil has an arc of 180 degrees.

[0090] When the system is a linear displacement system, the transmitting coil is rectangular, the receiving coil is distributed in the transmitting coil, the receiving coil is triangular wave geometric size distribution, and the two-way receiving coil in each group is distributed with a phase difference of 180 degrees, and the receiving coil distribution maintains its own geometric symmetry; when the system is an angular displacement system, the transmitting coil is circular, the receiving coil is distributed in the transmitting coil, the receiving coil is triangular wave distribution with a phase difference of 90 degrees or 180 degrees on the edge of the concentric circle with a radius of R0 smaller than the radius of the transmitting coil, and the receiving coil is wound and distributed in a triangular wave manner around the 0 axis of the R0 circumference. The transmitting coil and the receiving coil cannot intersect, and the receiving coil avoids intersection through the overlayer hole on the PCB circuit board.

[0091] When the system is a linear displacement system, the metal object moving target 6 is rectangular and effectively covers the receiving coil, and the length of the metal object moving target 6 is 1 / 4 wavelength or 1 / 2 wavelength of the triangular wave geometric size; when the system is an angular displacement system, the metal object moving target 6 effectively covers the receiving coil, and the metal object moving target 6 is semicircular and arc-shaped.

[0092] When the system is a linear displacement system, if two transmitting coils are used, the transmitting coil one 1 and the transmitting coil two 2 are rectangular, the transmitting coil one 1 and the transmitting coil two 2 are distributed inside and outside, the transmitting coil one 1 surrounds the transmitting coil two 2, and the geometric size ratio of the transmitting coil one 1 and the transmitting coil two 2 is: the length ratio is 0.7-0.8; and the width ratio is 0.7-0.8;

[0093] When a resonant LC oscillation signal is used as the excitation signal, the amplitude ratio of the LC oscillation of the transmitting coil one 1 and the transmitting coil two 2 is between 0.4-0.5;

[0094] When a pulse signal ≤20 nanoseconds is used as the excitation signal, the amplitude ratio of the pulse of the transmitting coil one 1 and the transmitting coil two 2 is between 0.4-0.5;

[0095] When an e function exponential decay signal is used as the excitation signal, the starting constant current source current size ratio is between 0.4-0.5, and the decay constants are equal;

[0096] The interval of 0.4-0.5 can be adjusted to 0 and the pressure difference of 0 by the feedback adjustment circuit.

[0097] When the system is an angular displacement system, if two transmitting coils are used, the transmitting coil one 1 and the transmitting coil two 2 are circular, the transmitting coil one 1 and the transmitting coil two 2 are distributed inside and outside, the transmitting coil one 1 surrounds the transmitting coil two 2, and are distributed in concentric circles;

[0098] The geometric size radius ratio of the transmitting coil one 1 and the transmitting coil two 2 is 0.9;

[0099] When a resonant LC oscillation signal is used as the excitation signal, the amplitude ratio of the LC oscillation of the transmitting coil one 1 and the transmitting coil two 2 is between 0.7-0.8;

[0100] When a pulse signal ≤20 nanoseconds is used as the excitation signal, the amplitude ratio of the pulse of the transmitting coil one 1 and the transmitting coil two 2 is between 0.7-0.8, and the pulse width is the same;

[0101] When an e function exponential decay signal is used as the excitation signal, the starting constant current source current size ratio of the transmitting coil one 1 and the transmitting coil two 2 is between 0.7-0.8, and the decay constants are equal;

[0102] The interval of 0.7-0.8 can be adjusted to 0 and the pressure difference of 0 by the feedback adjustment circuit. The wire and current direction of the transmitting coil one 1 and the transmitting coil two 2 ensure that the magnetic flux of the transmitting coil one 1 and the transmitting coil two 2 pass through the PCB circuit board plane in opposite directions;

[0103] When the system is a linear displacement system, if one transmitting coil is used, the transmitting coil is rectangular, and the geometric dimensions of the transmitting coil, length a and width b, need to satisfy the constraint condition:

[0104] a=(Nb)², N is a natural number greater than or equal to 1;

[0105] The width b of the transmitting coil and the shortest vertical distance between the receiving coil distributed in one transmitting coil need to be greater than or equal to b / 2, if b / 2 is less than 5 mm, then it is at least 5 mm, and it increases in proportion to the square root of the number of ampere turns of one transmitting coil; the receiving coil is distributed in one transmitting coil and is periodically distributed in a 90-degree phase difference parabolic wave or a 90-degree phase difference triangular wave; if the receiving coil is distributed in one transmitting coil in a triangular wave, then the geometric dimensions of one transmitting coil, length a and width b, need to satisfy the constraint condition that the length a is greater than or equal to 10b;

[0106] When the system is an angular displacement system, if one transmitting coil is used, the transmitting coil is circular, and the receiving coil is distributed in one transmitting coil, and the excitation signal of one transmitting coil is:

[0107] When the excitation signal of one transmitting coil is a resonant LC oscillation signal, it can be periodically transmitted, and the transmission time width of each resonant LC oscillation signal is between 10 microseconds and 5000 microseconds, or it is continuously transmitted;

[0108] When the excitation signal of one transmitting coil is an e-function exponential decay signal, it must be periodically transmitted, and the transmission time width of the e-function exponential decay signal is between 1 microsecond and 1000 microseconds; when the internal receiving coil is not more than 4, it is symmetrically distributed around the center point; when the internal receiving coil is one, it must be spindle-shaped.

[0109] When the excitation signal of one transmitting coil is a pulse signal of ≤20 nanoseconds, the pulse signal on the transmitting coil is a periodic transmission signal, and the transmission time width of each pulse signal is not greater than 20 nanoseconds, and the amplitude can be configured and adjusted through a feedback circuit; the internal receiving coil is one and must be spindle-shaped, and a voltage holding circuit must be added in the detection device 5, and the voltage needs to be maintained for at least 16 AD sampling clocks. Embodiment

[0110] For the receiving coil, a calibration process is first performed, and an e-function exponential decay excitation signal is transmitted to the transmitting coil 1 and the transmitting coil 2; the feedback adjustment circuit adjusts the decay constant and the initial constant current source current size through the induced electromotive force of the receiving coil and its pressure difference, so that the induced electromotive force of the receiving coil and its pressure difference are both 0, and the calibration ends.

[0111] Specifically, when the metal object moving target 6 is not above the PCB circuit board plane where the transmitting coil and the receiving coil are located, the calibration process can be performed.

[0112] Specifically, the metal object moving target 6 in the sending coil and the receiving coil on the PCB circuit board plane above the special position, can do calibration process.

[0113] Specifically, the metal object moving target 6 in the sending coil and the receiving coil on the PCB circuit board plane above the special position, can do calibration process.

[0114] Specifically, the high precision timer start trigger workflow, T0 time, start constant current source circuit charging, T1 time charging is completed, sending coil and constant current source connection, gating resistor, discharge to the resistor, T2 time, lock the induced voltage of the receiving coil, and then AD sampling, a working cycle is completed. T1-T0 time width can be selected between 50-100 microseconds; T2-T1 time width, can be selected between 1 microseconds to 50 microseconds.

[0115] After calibration, the excitation signal of the sending coil is equal to the decay constant e function exponential decay signal with different initial current: And .

[0116] Therefore, at any time, the current of the sending coil is equal to the proportion after calibration. The differential of the excitation signal is obtained, and the magnetic flux change rate factor caused by the current change rate of the two-way sending coil is: And .

[0117] Therefore, the magnetic flux change rate factor of the sending coil in the receiving coil at any position is fixed and unchanged, that is, the initial calibration value. The magnetic field intensity distribution of the rectangular sending coil is symmetrically distributed with the rectangular center point, and also symmetrically distributed with the vertical bisector of the vertical long side and the wide side of the center point. The magnetic field intensity of the circular sending coil is symmetrically distributed with the center, and the magnetic field intensity contour is formed with R (R is less than the radius of the sending coil) as the radius. Since the decay constant , L is the intrinsic parameter inductance value of the sending coil, and the resistance R is the sum of the internal resistance and the discharge resistance, so by adjusting the feedback adjustment circuit, the adjustable resistance circuit in the configuration interval can be adjusted to make the decay constant of the sending coil equal.

[0118] Reference Figure 2, angular displacement device schematic diagram, 1, 2 are the sending coil one and the sending coil two, 6 is the metal object moving target, 3 and 4 are the A group receiving coil one and the A group receiving coil two, each receiving coil is divided into two 180-degree arc sub-coils, the two sub-coils are coupled, and the same name end and the opposite name end are connected through the sub-coil same name end and the opposite name end junction 9. At this time, the induced electromotive force of each receiving coil is the difference of the induced voltages of its two sub-coils. Since the magnetic field intensity of the circular sending coil is symmetrically distributed with the center, and the magnetic field intensity contour is formed on the circumference with R (R is smaller than the radius of the sending coil) as the radius, the induced electromotive force and the angle of each receiving coil sub-coil are in linear relationship. The A group receiving coil one 3 and the A group receiving coil two 4 can detect 0-180 degrees respectively, so the induced voltage of the A group receiving coil one 3 and the A group receiving coil two 4 is differentiated again, and the measurement range of 0-360 degrees can be measured. If 16-bit AD sampling is used, the theoretical accuracy of angular displacement is 180 / 2^16=0.0027 degrees.

[0119] Reference Figure 1 is a linear displacement device schematic diagram, 1, 2 are the sending coil one and the sending coil two, 6 is the metal object moving target, 3 and 4 are the A group receiving coil one and the A group receiving coil two, each receiving coil is in a triangular wave distribution.

[0120] The A group receiving coil one 3 and the A group receiving coil two 4 are distributed with a 90-degree phase difference, and the A group receiving coil one 3 and the A group receiving coil two 4 are designed for a wavelength range. For example, the range is 100 CM, so the wavelength of the A group receiving coil one 3 and the A group receiving coil two 4 is designed to be 100 CM, and the width of the metal object moving target 6 is 25 CM, so the moving range of the metal object moving target 6 is 75 CM. When the metal object moving target 6 moves linearly, it will cause the induced voltage of the A group receiving coil one 3 and the A group receiving coil two 4 to change periodically. Through this periodic change, the displacement of the metal object moving target 6 can be calculated. If 16-bit AD sampling is used, the theoretical accuracy of linear displacement is 75CM / 2^16=0.114 microns.

[0121] It should be specially pointed out that for high-range high-precision linear displacement, such as 200 CM or 500 CM high-range high-precision linear displacement, the sending coil one 1 and the sending coil two 2 can be used, the A group receiving coil one 3 and the A group receiving coil two 4 are a group, the B group receiving coil one 7 and the B group receiving coil two 8 are a group, one receiving coil group A, one triangular wavelength completes full-range precision detection, and then the other receiving coil group B completes high-precision detection with N times of triangular wavelength, two groups of receiving coils cooperate to detect and calculate, and high-range high-precision linear displacement detection is completed. N is preferably a multiple of 4.

[0122] Reference Figure 3 In the middle, 3 and 4 are a pair of receiving coils A group, 7 and 8 are another group of 2 receiving coils B group. For example, A group, 200CM range, 1 wavelength, then A group every triangle wavelength 200CM; B group, 200CM range, 4 wavelengths, then B group every triangle wavelength 50CM.

[0123] Example 2: periodic parabolic receiving coil linear displacement:

[0124] Constructing the receiving coil geometry distribution function parabola Or the triangular wave y=x, and the size of the transmitting coil , will greatly reduce the amount of dsp calculation. If the 2-way Or the receiving coil of the triangular wave y=x is constructed, and the 2-way difference calculation is carried out, a lot of operation can be offset, and the x position and linear displacement can be calculated.

[0125] Need to be specially pointed out is that the excitation signal has three kinds:

[0126] 1. Resonant LC oscillation signal;

[0127] 2. Pulse signal ≤20 nanoseconds;

[0128] 3. e function exponential decay signal.

[0129] 20 nanosecond pulse signal is essentially a full frequency domain signal, equivalent to a full pass filter, simple to implement, but easy to be affected by signals of various frequencies. Resonant LC oscillation signal is a single point frequency domain signal, simple to implement, but easy to be affected by fixed bias magnetic field such as magnet, for example Suppose a magnet is placed beside the transmitting coil and the receiving coil, and the fixed bias magnetic field formed by the magnet is d, then the rate of change of magnetic flux it increases in a sine wave period is 2d. This will affect the frequency and phase of the sine wave, and ultimately affect the measurement accuracy.

[0130] But for the e function exponential decay excitation signal, the total magnetic flux is , the induced electromotive force is , that is, the influence of the fixed bias magnetic field is 0. So the e function exponential decay excitation signal is non-magnetic and anti-magnet.

[0131] Even if this fixed bias magnetic field is time-varying: , the induced electromotive force is , since C=R / L, the resistance is ohm level, and the inductance is micro henry level. The value of C is 10 to the power of 6, the change of is relatively small to C, which can be ignored.

[0132] However, it is affected for high frequency alternating external interference high power magnetic field (for example, power very high megahertz radio frequency signal), but as long as the emission interference source vector distance is more than 5cm, it is not affected.

[0133] Therefore, the preferred e function exponential decay excitation signal of the patent.

[0134] Please refer to Figure 4 And Figure 5 A transmitting coil 1, which contains A group of receiving coil 1 3 and A group of receiving coil 1 4, two receiving coils are periodically parabolic formula: Periodic distribution. Where X value range is 【0, 2h】; Where X value range is 【0, h】.

[0135] Thus we can get a parabolic function with Periodic distribution of wavelength 4h, the phase difference between y1 and y2 is 2h-h=h, just 1 / 4 wavelength, 90 degree phase difference. Figure 5 11 is y1, 10 is y2.

[0136] Y1 (102) is translated along the X axis h and 2h units, respectively, 103 and 104.

[0137] Y1 (102) is flipped to the Y axis below the X axis to get 109.

[0138] Again 109 along the X axis h and 2h units, respectively, 108 and 107.

[0139] Y2 (101) is flipped to the Y axis below the X axis to get 110.

[0140] After 101 and 110 are rotated 180 degrees along the Y axis, and then translated 4h units along the X axis, respectively, 105 and 106 are obtained.

[0141] After the above operation, the PCB receiving coil group is drawn, forming a two-way receiving coil with periodic parabolic formula distribution and 90 degree phase difference.

[0142] Where y and x are in square relationship, which can partially eliminate the square root calculation, and can simplify the integral and differential calculation, greatly reducing the calculation amount. And the geometric size of the two receiving coils is geometrically symmetrical in the transmitting coil, only the phase difference is 90 degrees. It is easy to perform differential calculation on the induced electromotive force of the two receiving coils again.

[0143] Need to be specially pointed out that,​ X-axis and Y-axis linear stretching and coordinate system linear transformation are performed.

[0144] The above are only preferred embodiments of the present application, and are used to help understand the method and its core idea of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments only, and any technical solution belonging to the idea of the present application is within the protection scope of the present application. It should be pointed out that, for ordinary skilled in the art, some improvements and refinements without departing from the principles of the present application are also considered as the protection scope of the present application.

[0145] The present application solves the various deficiencies of the grating sensor in the prior art as a whole, solves the deficiencies of the grating sensor through linear displacement combined with angular displacement detection, differentially detects the output signal of the induction coil, has high sensitivity, and is suitable for the working environment of micro-power consumption and micro-signal.

Claims

1. A high-precision linear displacement and angular displacement system, characterized in that, The device includes a moving metal object target (6), a detection device (5), a PCB circuit board, and a planar coil. The planar coil is printed on the PCB circuit board and includes a transmitting coil and a receiving coil. The transmitting coil and the receiving coil are connected to the detection device (5). The detection device (5) includes a signal driving circuit, a signal receiving circuit, a detection circuit, a 16-bit AD sampling circuit, a constant current source circuit with adjustable current, an adjustable interval resistance circuit, a feedback adjustment circuit, a nanosecond-level high-precision timer, and an adjustable amplitude oscillation circuit. The transmitting coil includes a transmitting coil one (1) and a transmitting coil two (2). The receiving coil includes a group A receiving coil one (3) and a group A receiving coil two (4), as well as a group B receiving coil one (7) and a group B receiving coil two (8). The moving metal object target (6) is placed non-contactly above the transmitting coil and the receiving coil. The moving metal object target (6) is parallel to the PCB circuit board. The excitation signal on the transmitting coil maintains a specific ratio range characteristic and achieves a precise value through calibration. The excitation signals that drive the transmitting coil in the signal driving circuit are as follows: Resonant LC oscillation signal; Pulse signals ≤20 nanoseconds; e-function exponentially decaying signal; When the transmitting coil one (1) and transmitting coil two (2) are two independent planar coils, then these two transmitting coils maintain: If the excitation signal is selected as the resonant LC oscillation signal, the resonant LC oscillation signals of transmitting coil one (1) and transmitting coil two (2) will remain in phase and frequency, and the oscillation amplitude will remain at a certain ratio. If the excitation signal is selected as a pulse signal of ≤20 nanoseconds, then the pulse signals of transmitting coil one (1) and transmitting coil two (2) are synchronized, that is, transmitted simultaneously, with the same pulse width and the pulse amplitude maintained at a certain ratio. If the excitation signal is selected as the exponentially decaying e-function signal, the starting current of the decaying signals of transmitting coil one (1) and transmitting coil two (2) will maintain a certain ratio and the decay constants will be equal.

2. The high precision linear and angular displacement system according to claim 1, characterized in that, The feedback adjustment circuit adjusts the magnitude of the constant current source current, the oscillation amplitude of the oscillation circuit, the value of the interval resistor, the pulse amplitude, and the pulse width. The oscillation amplitude, interval resistor, constant current source magnitude, pulse amplitude, and pulse width are all continuously adjustable within the interval range.

3. The high precision linear and angular displacement system according to claim 1, wherein, The receiving coil is distributed on the PCB circuit board in the form of a periodic parabola y=x² or a triangular wave.

4. The high precision linear and angular displacement system of claim 1, wherein, The formula for maintaining the characteristic of the long side a and the wide side b of the transmitting coil on the PCB circuit board is: a = (Nb)², where N is a natural number ≥ 1.

5. The high precision linear and angular displacement system of claim 1, wherein, The moving target of the metal object (6) is rectangular, semi-circular or arc-shaped.

6. The high precision linear and angular displacement system of claim 1, wherein, The number of transmitting and receiving coils used is related to the available space on the PCB board, the accuracy of linear displacement and angular displacement in engineering measurements.

7. The high-precision linear and angular displacement system according to claim 1, characterized in that, The receiving coil and the transmitting coil are in the same plane of the PCB circuit board, and the receiving coil is distributed within the geometric range of the transmitting coil. The receiving coil senses the induced electromotive force generated by the change in magnetic flux caused by the change in the excitation signal current on the transmitting coil. The receiving coil is connected to the signal receiving circuit, and the detection device (5) detects the change in the induced electromotive force of the receiving coil.

8. The high-precision linear and angular displacement system according to claim 1, characterized in that, The transmitting coil maintains geometric symmetry, and the magnetic field distribution within the transmitting coil ensures symmetry. The receiving coils are distributed within the transmitting coils and located in the same plane of the PCB circuit board. The receiving coils also maintain symmetry, ensuring that at least one receiving coil has a zero induced electromotive force when no metal object is present.

9. The high-precision linear and angular displacement system according to claim 1, characterized in that, The receiving coils are divided into groups A and B, with each group consisting of two channels. The receiving coils in each group are geometrically symmetrical. While ensuring the symmetry of the receiving coil routing, each receiving coil is divided into two sub-coils. The same-named terminals and different-named terminals of the two sub-coils are connected to ensure that when there is no metal object, at least one receiving coil in each group has an induced electromotive force of 0.

10. The high-precision linear and angular displacement system according to claim 1, characterized in that, When the transmitting coil has two paths, in the absence of the moving metal object target (6), the feedback adjustment circuit is used to calibrate the electrical parameters of the excitation signal of the transmitting coil. The feedback adjustment circuit adjusts the electrical parameters of the excitation signal of the transmitting coil according to the change in the electrical parameters of the induced signal of the receiving coil, so that the induced electromotive force voltage difference of the receiving coil is equal and the voltage difference of the sub-coils of each receiving coil is equal. Specifically: Resonant LC oscillation signal: The feedback circuit adjusts the oscillation amplitude of the LC oscillation circuit; Pulse signals ≤20 nanoseconds: The feedback circuit adjusts the amplitude and width of the pulse signal; e-function exponential decay signal: The feedback circuit adjusts the starting current and decay constant to make the decay constants of the two transmitting coils equal; When the transmitting coil is a single coil, only the pulse amplitude, constant current source size, and oscillation amplitude of the LC oscillation circuit need to be adjusted.

11. The high-precision linear and angular displacement system according to claim 1, characterized in that, When the system is a linear displacement system, the transmitting coil is rectangular, and the receiving coils are distributed within the transmitting coil. The receiving coils have a triangular wave geometric distribution, and the two receiving coils in each group are distributed with a 90-degree phase difference, and the distribution of the receiving coils maintains its own geometric symmetry. When the system is an angular displacement system, the transmitting coil is circular, and the receiving coils are distributed within the transmitting coil. The receiving coils have a chordal geometric distribution, and the receiving coils are symmetrically distributed around the center of the transmitting coil; the chordal degree of the receiving coil is 180 degrees.

12. The high-precision linear and angular displacement system according to claim 11, characterized in that, When the system is a linear displacement system, the transmitting coil is rectangular, and the receiving coils are distributed within the transmitting coil. The receiving coils are distributed with triangular wave geometry, and the two receiving coils in each group are distributed with a 180-degree phase difference. The distribution of the receiving coils maintains its own geometric symmetry. When the system is an angular displacement system, the transmitting coil is circular, and the receiving coils are distributed within the transmitting coil. The receiving coils are distributed with triangular waves of 90-degree or 180-degree phase difference on the concentric circle with a radius R0 smaller than the radius of the transmitting coil. With the circumference of the circle R0 as the zero axis, the receiving coils are distributed in a triangular wave manner, winding vertically. The transmitting coil and the receiving coil cannot intersect, and the receiving coils avoid connection through through-holes on the PCB circuit board.

13. The high-precision linear and angular displacement system according to claim 1, characterized in that, When the system is a linear displacement system, the moving target of the metal object (6) is rectangular, effectively covering the receiving coil, and the length of the moving target of the metal object (6) is 1 / 4 wavelength or 1 / 2 wavelength of the geometric dimension of the triangular wave. The system is an angular displacement system, and the moving metal object (6) effectively covers the receiving coil. The moving metal object (6) is semi-circular and arc-shaped.

14. The high-precision linear and angular displacement system according to claim 1, characterized in that, When the system is a linear displacement system, if two transmitting coils are used, then transmitting coil one (1) and transmitting coil two (2) are rectangular, transmitting coil one (1) and transmitting coil two (2) are distributed inside and outside, transmitting coil one (1) surrounds transmitting coil two (2), and the geometric ratio of transmitting coil one (1) and transmitting coil two (2) is: length ratio of 0.7 to 0.8; width ratio of 0.7 to 0.8; When the resonant LC oscillation signal is used as the excitation signal, the amplitude ratio of the LC oscillation of the transmitting coil one (1) and the transmitting coil two (2) is between 0.4 and 0.

5. When the ≤20 nanosecond pulse signal is used as the excitation signal, the amplitude ratio of the pulses of the transmitting coil one (1) and the transmitting coil two (2) is between 0.4 and 0.5; When the exponentially decaying e-function signal is used as the excitation signal, the magnitude ratio of the initial constant current source current is between 0.4 and 0.5, and the decay constants are equal. The range of 0.4 to 0.5 is adjusted by the feedback adjustment circuit until the induced electromotive force of the receiving coil is 0 and the voltage difference is 0. When the system is an angular displacement system, if two transmitting coils are used, transmitting coil one (1) and transmitting coil two (2) are circular, transmitting coil one (1) and transmitting coil two (2) are distributed inside and outside, transmitting coil one (1) surrounds transmitting coil two (2) and are distributed in concentric circles; The ratio of the geometric radius of the transmitting coil one (1) and the transmitting coil two (2) is 0.9; When the resonant LC oscillation signal is used as the excitation signal, the amplitude ratio of the LC oscillation of the transmitting coil one (1) and the transmitting coil two (2) is between 0.7 and 0.8; When the ≤20 nanosecond pulse signal is used as the excitation signal, the amplitude ratio of the pulses of the transmitting coil one (1) and the transmitting coil two (2) is between 0.7 and 0.8, and the pulse width is the same; When the exponentially decaying e-function signal is used as the excitation signal, the ratio of the initial constant current source current of the transmitting coil one (1) and the transmitting coil two (2) is between 0.7 and 0.8, and the decay constants are equal. The range of 0.7 to 0.8 is adjusted by the feedback adjustment circuit to make the induced electromotive force of the receiving coil 0 and the voltage difference 0; the routing and current direction of the transmitting coil one (1) and the transmitting coil two (2) ensure that the magnetic flux passing through the magnetic field lines of the PCB circuit board plane are opposite to each other.

15. The high-precision linear and angular displacement system according to claim 1, characterized in that, When the system is a linear displacement system, if one transmitting coil is used, the transmitting coil is rectangular, and the geometric dimensions of the transmitting coil, length a and width b, are subject to the following constraints: a = (Nb)², where N is a natural number ≥ 1; The shortest vertical distance between the wide side b of the transmitting coil and the receiving coil distributed within the transmitting coil must be ≥ b / 2. If b / 2 is less than 5 mm, then it must be at least 5 mm, and it increases proportionally to the square root of the ampere-turns of the transmitting coil. The receiving coils are distributed within the transmitting coil and are periodically distributed in a parabolic pattern with a 90-degree phase difference, or periodically distributed in a triangular wave pattern with a 90-degree phase difference. If the receiving coils are distributed within the transmitting coil with a triangular wavelength, then the geometric dimensions a and b of the transmitting coil must ensure that the constraint condition is that the length a ≥ 10b. When the system is an angular displacement system, if one transmitting coil is used, the transmitting coil is circular, and the receiving coils are distributed within the one transmitting coil. The excitation signal of the one transmitting coil is: When the excitation signal of the one transmitting coil is a resonant LC oscillation signal, it is transmitted periodically, with each transmission of the resonant LC oscillation signal having a transmission time width between 10 microseconds and 5000 microseconds, or it is transmitted continuously; When the excitation signal of the single transmitting coil is an exponentially decaying e-function signal, it must be transmitted periodically. The transmission time of the exponentially decaying e-function signal is between 1 microsecond and 1000 microseconds. When there are no more than 4 internal receiving coils, they are symmetrically distributed around the center point. When there is only 1 internal receiving coil, it must be distributed in a spindle shape. When the excitation signal of the one transmitting coil is a pulse signal of ≤20 nanoseconds, the pulse signal on the transmitting coil is a periodic transmitting signal. The transmission time width of each pulse signal is no more than 20 nanoseconds, the amplitude is configurable, and it can be adjusted by the feedback adjustment circuit. The internal receiving coil is one and must be spindle-shaped. The detection device (5) must add a voltage holding circuit, and the voltage must be held for at least 16 AD sampling clock cycles.

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