Signal conversion circuit, resistance meeting judgment method and electric lifting table

Abstract

The invention discloses a signal conversion circuit, a resistance meeting judgment method and an electric lifting table, the signal conversion circuit comprises a detection unit and a signal processing unit, the detection unit comprises a driving detection module and a pressure detection module, the driving detection module is used for obtaining a first electric signal of a driving assembly in the electric lifting table, and the pressure detection module is used for detecting the first electric signal; the pressure detection module is used for acquiring a second electric signal of a target area in the electric lifting table; the output end of the driving detection module and the output end of the pressure detection module are connected with the input end of the signal processing unit, the signal processing unit is used for converting a first electric signal into a rotating speed steering signal and converting a second electric signal into a resistance meeting signal, and the signal processing unit is further provided with an output end for outputting the rotating speed steering signal; the signal processing unit is further used for detecting the working state of the electric lifting table according to the first electric signal and the second electric signal and outputting a detection result, abnormal conditions in the operation process of the lifting table are judged, and equipment damage or potential safety hazards are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of electric lifting tables, and in particular to a signal conversion circuit, an obstacle determination method and an electric lifting table. Background Art

[0002] With the development of technology in the field of smart home, electric lift tables have emerged. Electric lift tables are convenient for height adjustment and can automatically rise and fall according to user needs, improving the comfort of office and home use. Its characteristics are that through the built-in motor and control system, users can easily adjust the height of the desktop to adapt to different working postures, thereby reducing health problems caused by long-term sitting. In addition, electric lift tables can also be linked with smart home systems to achieve personalized height settings and automatic adjustment, greatly improving the user experience.

[0003] In traditional anti-pinch solutions for lifting tables, resistance is usually determined by detecting motor current or using a gyroscope to determine the acceleration of the lifting table. However, these traditional methods have some problems. Due to the limitations of current detection and the gyroscope detection being easily disturbed by the vibration during the operation of the lifting table, the sensitivity of the system is not ideal and the resistance detection is not accurate enough, which may cause the anti-pinch function to fail or react slowly. Summary of the invention

[0004] Based on this, it is necessary to provide a signal conversion circuit and an electric lifting table to address the above problems.

[0005] The present application provides a signal conversion circuit, which is arranged on a motor of an electric lifting table, and includes a signal processing unit and a detection unit, wherein: The detection unit includes a drive detection module and a pressure detection module, wherein the drive detection module is used to obtain a first electrical signal of a drive component in the electric lift table, and the pressure detection module is used to obtain a second electrical signal of a target area in the electric lift table; The output ends of the drive detection module and the pressure detection module are respectively connected to the input end of the signal processing unit. The signal processing unit is used to convert the first electrical signal into a speed steering signal and convert the second electrical signal into a resistance signal. The signal processing unit also has an output end for outputting the speed steering signal.

[0006] Optionally, the pressure detection module includes a plurality of strain signal detection circuits, and the plurality of strain signal detection circuits are arranged in a plurality of target areas of the driving component to together form a detection network; The plurality of strain signal detection circuits are connected in series or in parallel.

[0007] Optionally, the drive detection module includes a plurality of drive signal detection circuits, and the first electrical signal is a Hall signal output by the drive signal detection circuit.

[0008] Optionally, the signal processing unit includes a signal processor and a signal synthesis circuit, the signal processor is connected to the signal synthesis circuit, the signal processor is used to extract the rotation speed information and steering information in the first electrical signal, and convert the steering information into signal amplitude, and convert the rotation speed information into pulses, which are compressed, mixed and encoded and then output to the signal synthesis circuit.

[0009] Optionally, the strain signal detection circuit includes a pressure sensor and a signal filtering and amplifying circuit, wherein the pressure sensor is arranged at a structurally deformable position of the driving component to generate a piezoelectric signal related to the deformation; and the signal filtering and amplifying circuit is used to filter and amplify the piezoelectric signal.

[0010] Optionally, the pressure detection module also includes a DC coupling capacitor and an AC coupling capacitor, the DC coupling capacitor is used to generate a DC bias at the input end of the signal filtering and amplifying circuit, and the AC coupling capacitor is used to suppress differential mode interference generated by the piezoelectric sensor.

[0011] Optionally, the driving signal detection circuit includes a Hall sensor and a filtering circuit, the Hall sensor is used to generate a Hall signal following the change of the magnetic field of the driving component, and the Hall signal is output via the filtering circuit.

[0012] Optionally, the Hall sensors are arranged in pairs at the periphery of the driving component, and the pair of Hall sensors are orthogonally arranged on the same spatial plane.

[0013] The present application also provides an obstruction determination method, which uses the above-mentioned signal conversion circuit and also includes the following steps: Generate a corresponding electrical signal according to the deformation degree of the target area, and filter and amplify the electrical signal to form a second electrical signal; The second electrical signal is continuously sampled to obtain continuous sampling signals CN1[M], CN2[M], ..., CN n [M]; The continuous sampling signals CN1[M], CN2[M], ..., CN n [M] Perform Kalman filtering; When the driving component is in operation, if CN in the continuous sampling signal n+1 [M] and CN n [M] The difference after Kalman filtering is greater than the first preset value, or the continuous sampling signal CN n [M]~ CN n+cIf the number of values ​​in [M] that are greater than the first threshold value exceeds a second preset value, it is determined that the motor structure corresponding to the piezoelectric sensor encounters resistance.

[0014] The present application also provides an electric lifting table, including the above-mentioned signal conversion circuit, and also includes a drive component and a control box, wherein the control box is used to obtain the detection result output by the signal processing unit and adjust the motion state of the drive component according to the detection result.

[0015] The above-mentioned signal conversion circuit can collect the operating status data of the electric lift table in real time through the drive detection module and pressure detection module in the detection unit, including the speed and steering information of the drive component, and the deformation information of the target area. This real-time monitoring ensures that the system can grasp the working status of the electric lift table at any time, and then provide basic data support for subsequent intelligent control. The signal processing unit combines the speed, steering and resistance signals to accurately determine whether the electric lift table has any abnormal conditions during operation. Through rapid detection of the resistance state, the system can quickly take protective measures, such as stopping the movement of the drive component, when the electric lift table encounters an obstacle, clamps an object or contacts the user. This function effectively prevents accidental clamping of users or damage to the table or objects on the table, greatly improving the safety of the equipment.

[0016] The above-mentioned method for judging the obstruction can effectively remove noise and accurately capture the changes in the piezoelectric sensor signal through multiple sampling and filtering and amplification, thus achieving high-sensitivity obstruction detection. Comprehensive judgment is made through the two conditions of the difference between the maximum and minimum values ​​and the number of large values ​​to ensure the reliability of obstruction detection and reduce the misjudgment that may be caused by a single condition. According to the working state of the motor, the corresponding judgment threshold is set to improve the adaptability and detection effect of the system under different working conditions. Through real-time sampling and continuous analysis, the motor's opportunity obstruction state can be quickly judged, and the protection mechanism (such as stopping the motor or reverse operation) can be triggered in time to ensure the safe operation of the electric lifting table and prevent equipment damage or user injury.

[0017] In the above-mentioned electric lift table, the control box receives the detection results output by the signal processing unit, such as speed, steering information, and resistance signals. When an abnormality is detected (such as encountering resistance or obstacles), the control box can immediately instruct the drive component to pause or change direction, thereby protecting the safety of the lift table and the user. Through the coordination of the control box, the electric lift table can achieve intelligent control, which can not only realize the basic lifting function, but also have automatic anti-pinch, anti-collision and other safety functions. Under the command of the control box, the drive component can perform lifting actions according to demand to realize the basic functions of the lift table. Through the signal conversion circuit, when the drive component encounters resistance or abnormal conditions, it can adjust the motion state according to the feedback of the control box to avoid possible damage or safety hazards. The motion state of the drive component can not only be detected, but also adjusted as needed, which enhances the safety and intelligence of the electric lift table. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a signal conversion circuit provided in one embodiment of the present application; Figure 2 A further structural schematic diagram of a signal conversion circuit provided in one embodiment of the present application; Figure 3 A schematic diagram of the structure of a pressure detection module in a signal conversion circuit provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of a driving signal detection circuit in a signal conversion circuit provided in an embodiment of the present application; Figure 5 A schematic diagram of the working principle of a driving signal conversion circuit in a signal conversion circuit provided in an embodiment of the present application; Figure 6 A waveform diagram of a Hall signal collected in a signal conversion circuit provided in an embodiment of the present application; Figure 7 A schematic diagram of the structure of a signal synthesis circuit in a signal conversion circuit provided in an embodiment of the present application; Figure 8 A schematic diagram of a flow chart of an obstruction determination method provided in an embodiment of the present application; Fig. 9 A schematic diagram of a process flow of multi-channel strain signal detection of an obstruction determination method provided in an embodiment of the present application; Fig.10 A schematic diagram of the determination process of an obstruction determination method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0024] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0025] See also Figure 1 , an embodiment of the present invention provides a signal conversion circuit, which is arranged on the motor of the electric lifting table, and includes a detection unit and a signal processing unit, wherein: The detection unit includes a drive detection module and a pressure detection module, the drive detection module is used to obtain a first electrical signal of a drive component in the electric lift table, and the pressure detection module is used to obtain a second electrical signal of a target area in the electric lift table; the output ends of the drive detection module and the pressure detection module are respectively connected to the input end of the signal processing unit, the signal processing unit is used to convert the first electrical signal into a speed steering signal, and convert the second electrical signal into an obstruction signal, and the signal processing unit also has an output end for outputting a speed steering signal; The signal processing unit is also used to detect the working state of the electric lifting table according to the resistance signal and the speed steering signal, or according to the resistance signal, and output the detection result.

[0026] See also Figure 2 In this embodiment, the drive detection module is used to obtain the first electrical signal (Hall1 and Hall2) of the motor drive component in the electric lifting table. The drive detection module captures the magnetic field changes of the motor magnetic ring and outputs two periodic electrical signals Hall1 and Hall2. The frequency of these two signals is proportional to the speed of the motor, and the phase difference between them can be used to determine the direction of the motor. The pressure detection module is used to obtain the degree of deformation of the target area and output a second electrical signal (deformation signal, i.e. CN1, CN2, ..., CNn). When the electric lifting table is running, if it encounters resistance or obstacles, the piezoelectric sensor installed in the target area will deform due to the force and output an electrical signal proportional to the degree of force. The signal processing unit is responsible for receiving the first electrical signal and the second electrical signal output by the detection unit, and processing and judging them. Its main functions include the generation of the speed steering signal (Hall_OUT), the processing of the resistance signal, and the comprehensive judgment of the working state. After comprehensive analysis, the detection result is output to indicate the real-time working state of the electric lifting table.

[0027] Through the drive detection module and pressure detection module in the detection unit, the circuit can collect the operating status data of the electric lift table in real time, including the speed and steering information of the drive component, and the deformation information of the target area. This real-time monitoring ensures that the system can grasp the working status of the electric lift table at any time, and then provide basic data support for subsequent intelligent control. The signal processing unit combines the speed, steering and resistance signals to accurately determine whether the electric lift table has any abnormal situation during operation. For example, when the lift table encounters an obstacle or is subject to resistance, the pressure detection module will detect the deformation of the target area, and the signal processing unit can quickly identify and determine it as an obstruction state. Similarly, if the drive detection module detects an abnormal speed (such as too fast or too slow) or an abnormal steering (such as reversal), the signal processing unit can also promptly determine the abnormal situation. Through the rapid detection of the obstruction state, the system can quickly take protective measures, such as stopping the movement of the drive component, when the electric lift table encounters an obstacle, clamps an object or contacts a user. This function effectively prevents accidental clamping of users or damage to the table or desktop objects, greatly improving the safety of the equipment.

[0028] See also Figure 2 and Figure 3 The signal conversion circuit provided in this embodiment, the pressure detection module includes a plurality of strain signal detection circuits, the plurality of strain signal detection circuits are arranged in a plurality of target areas of the driving component, and together form a detection network; the plurality of strain signal detection circuits are connected in series or in parallel with each other. The strain signal detection circuit includes a plurality of piezoelectric sensors, a first operator and a second operator, the plurality of piezoelectric sensors are respectively arranged at the structural weak points of the driving component, and are respectively connected to the first operator and the second operator, the signal collected by the piezoelectric sensor is sent to the second operator, the second operator is used to amplify the piezoelectric sensor signal, and the first operator is used to provide a corresponding DC bias voltage for the second operator circuit.

[0029] See also Figure 2 and Figure 3 The signal conversion circuit provided in this embodiment, the strain signal detection circuit also includes a signal filter amplifier circuit, the signal filter amplifier circuit is used to filter and amplify the piezoelectric signal. The signal filter amplifier circuit specifically includes a first filter voltage divider structure and a second filter voltage divider structure, the first filter voltage divider structure is connected to the first operator, and the second filter voltage divider structure is arranged at the output end of the second operator.

[0030] See also Figure 2 and Figure 3 The signal conversion circuit provided in this embodiment, the strain signal detection circuit also includes a DC coupling capacitor and an AC coupling capacitor. The DC coupling capacitor is used to generate a DC bias at the input end of the second operator, and the AC coupling capacitor is used to suppress the differential mode interference generated by the piezoelectric sensor.

[0031] In this embodiment, the strain signal detection circuit is as follows: Figure 3 As shown in the figure, CN is a piezoelectric sensor. When it is deformed by force, an electrical signal Vcn will be generated, reflecting the magnitude of the force applied by the outside world. The electrical signal is a weak DC signal and needs to be amplified and filtered for subsequent processing. IC1B is specifically a voltage follower, which provides a suitable DC bias voltage for the second operator IC1A. In this embodiment, the first operator IC1B is a voltage follower, which has the characteristics of large input impedance, small output impedance, and strong anti-interference ability. The power supply VCC is divided by R10 and R11, and then transferred by the first operator IC1B to provide a DC bias voltage Vd for the second operator IC1A. For the subsequent circuit, the output signal needs to be positive (voltage greater than 0), but the piezoelectric sensor signal Vcn can be positive or negative, so the second operator IC1A relies on the DC bias voltage provided by the first operator IC1B to change the output signal to Vd+ɑVcn, so that the signal is always positive. Here, ɑ represents the amplification factor (or gain) of the signal, which is a positive number greater than 1.

[0032] In this embodiment, the first filter voltage-dividing structure is specifically composed of R10, R11 and C8, and the second filter voltage-dividing structure is specifically composed of R13, R15 and C7. In the first filter voltage-dividing structure, resistors R10 and R11 play the role of direct current voltage division, adjusting the electrical signal from VCC to a suitable voltage level, and the voltage-divided signal enters the first operator IC1B, and ports 5, 6, and 7 are the in-phase input terminal, inverting input terminal, and output terminal of IC1B respectively. C8 is a filter capacitor, and its main function is to form a low-pass filter through the combination with the voltage-dividing resistors R10 and R11 to smooth the fluctuations in the power supply signal and remove high-frequency noise. In the second filter voltage-dividing structure, the voltage-dividing resistors R13 and R15 constitute a voltage-dividing loop, adjusting the amplified signal to a suitable level, and the voltage-divided signal is convenient for the processing of the subsequent circuit to ensure the level matching with the next level circuit. Resistor R12 is used for current limiting at the output end of IC1B and suppressing signal oscillation. C7 is an output filter capacitor, mainly used to smooth the output signal of the amplifier circuit (IC1A), suppress high-frequency noise and improve signal quality.

[0033] In addition, in this embodiment, ports 1, 2, 3, 4, and 8 are respectively the output terminal, the inverting input terminal, the non-inverting input terminal, the negative voltage input port of the power supply, and the positive voltage input port of the power supply of IC1A. R3 is a current limiting resistor, and C3 is a DC coupling capacitor, which plays a DC coupling role at the positive input terminal (V+) of IC1A, and provides a stable DC bias for the input terminal. This DC bias ensures that the DC component of the signal is correctly transmitted, so that the amplifier circuit can work normally. The second operator IC1A and resistors R4, R5, R7, and R8 together constitute a proportional operation circuit to further amplify the signal. The signal amplified by IC1A will be synchronized to the output terminal of IC1A for subsequent processing. Resistor R9 is used to balance the input impedance and reduce the bias voltage and current imbalance. Capacitor C6 is an AC coupling capacitor, which plays an AC coupling role, and cooperates with the operation circuit to effectively suppress the differential mode interference generated from the CN terminal. Through C6, high-frequency noise and interference signals are filtered out to ensure that the signal input by the amplifier is more stable and clear. C4 is a phase compensation capacitor, which is used to stabilize the phase response of the amplifier and prevent circuit oscillation. Through phase compensation, C4 improves the stability of the circuit at high frequencies. C5 is a filter capacitor, which is used to further remove high-frequency noise in the signal. These filter capacitors ensure that the amplified output signal is smoother and help improve the accuracy of the signal. The output end of the second filter voltage divider structure is also connected to a resistor R14. Resistor R14 plays a current limiting role to protect the amplifier and subsequent circuits from being affected by large currents. At the same time, R14 also helps to suppress possible interference signals and further improve the anti-interference performance of the circuit.

[0034] In this embodiment, the piezoelectric sensor in the pressure detection module is arranged at a structural weak point in the lifting table, specifically at the wall surface of the driving motor in the lifting table. When the operation of the electric lifting table is obstructed, the resistance will be transmitted from the desktop to the bracket. Since the connection point between the bracket and the table leg is the four walls of the motor, the four walls will be deformed. This arrangement can ensure that any change in resistance will cause deformation on the four walls of the motor, so that the piezoelectric sensor can sensitively detect these deformations and generate corresponding electrical signals. The piezoelectric sensor is installed on the four walls of the motor, and can detect the resistance encountered by the lifting table in a timely and accurate manner. Compared with the traditional current detection method, the piezoelectric sensor has a fast response speed and higher sensitivity. The piezoelectric sensor is installed on the four walls of the motor, which does not take up additional space, and can directly use the existing structure to achieve a simple and effective detection design. This arrangement transmits the resistance signal to the detection module through the natural conduction path of the mechanical force, reduces the probability of false alarms caused by other vibrations or electromagnetic interference, and improves the reliability of the detection system.

[0035] Specifically, in this embodiment, multiple piezoelectric sensors are set at multiple structural weak points of the motor. When the motor is running, the external force is transmitted to the motor wall through the desktop and the bracket. However, due to the different directions of force transmission, a single piezoelectric sensor can only detect the resistance signal at its location, and there may be a detection blind spot for forces or deformations in other directions. The resistance signal of the motor is unevenly distributed, and some structural areas may not meet the sensitivity required by the design, resulting in inaccurate resistance detection or missed detection.

[0036] Arrange multiple piezoelectric sensors at multiple structural weak points of the motor to form a multi-point detection network, which effectively improves the coverage of deformation detection. Each piezoelectric sensor independently detects the resistance signal in its area, avoiding the blind spot of a single piezoelectric sensor due to different force conduction directions. Through the comprehensive analysis of multi-point signals, it is possible to more sensitively capture the tiny resistance signal when the motor encounters resistance, ensuring the timeliness and accuracy of resistance detection. The signal processing unit can make a comprehensive judgment on the resistance signals in different areas to further improve the detection accuracy. After receiving the signals from multiple piezoelectric sensors, the signal processing unit can eliminate false detection and noise interference by comprehensively processing and comparing the resistance signals, thereby improving the reliability of the system.

[0037] See also Figure 2 and Figure 4 The signal conversion circuit provided in this embodiment, the drive detection module includes a plurality of drive signal detection circuits, the drive signal detection circuit is connected to the signal processor, the first electrical signal is a Hall signal output by the drive signal detection circuit, wherein the drive signal detection circuit includes a Hall sensor and a filter circuit, the Hall sensor is used to sense the change of the magnetic field of the drive component and output the Hall signal, and the Hall signal is output via the filter circuit; the Hall sensor includes a first end, a second end and a third end, the first end is used to connect to the power supply, the second end is used to be grounded, and the third end is used to output the Hall signal.

[0038] The signal conversion circuit provided in this embodiment, the filter circuit includes a pull-up resistor and a filter capacitor, the third end of the Hall sensor is connected to the power supply through the pull-up resistor, and is connected to the ground through the filter capacitor.

[0039] In the signal conversion circuit provided in this embodiment, the Hall sensors are arranged in pairs at the periphery of the driving component, and the pair of Hall sensors are arranged orthogonally on the same spatial plane.

[0040] In this embodiment, the driving signal detection circuit is as follows Figure 4As shown in the figure, HALL1 and HALL2 are Hall sensors, M is the driving component, i.e. the motor, and the figure also includes the power port 1 (VCC), data output port 2 (OUT) and ground port 3 (GND) of the Hall sensor. The VCC and GND ports jointly provide stable working power and ground for the sensor to ensure the normal operation of the sensor. The data output port OUT is responsible for outputting the detection results of the Hall sensor. When the sensor detects a magnetic field, it will generate a voltage signal related to the strength and direction of the magnetic field, which will be output from the OUT port after internal amplification and filtering. R1 and R2 are pull-up resistors, and C1 and C2 are filter capacitors. The pull-up resistors R1 and R2 ensure that the output signal is stable at the logic level, while the filter capacitors C1 and C2 eliminate high-frequency noise to ensure the stability and accuracy of the signal.

[0041] In this embodiment, a pair of orthogonally placed Hall sensors are used. The orthogonally arranged Hall sensors can use the phase difference to detect the direction of the drive component. When the motor rotates, the two sets of sensors will generate pulse signals of different phases. The signal processing unit can determine the rotation direction of the motor by detecting the relative order or phase difference of these pulse signals. This orthogonal arrangement increases the sensitivity and accuracy of the detection, ensuring that the system can accurately detect the direction under different steering conditions, thereby achieving more reliable status monitoring. The orthogonal setting can also effectively distinguish between forward and reverse rotation and stagnant states, further improving the accuracy of motor status judgment.

[0042] See also Figures 5 to 7 The working principle of the dual-channel Hall sensor to collect the motor speed and direction is mainly based on the Hall effect and pulse counting method. In the motor control application, firstly, magnets arranged alternately are installed on the motor shaft, and a dual-channel Hall sensor is installed on one side of the motor shaft. When the motor rotates, the N pole and S pole of the magnet will pass through the sensing surface of the sensor in turn, thereby changing the magnetic field around the sensor. This change in the magnetic field will cause the change in the output voltage of the sensor, and then output a series of pulse signals. By measuring the frequency of these pulse signals, that is, the number of pulse signals per unit time, the speed of the motor can be calculated, because each pulse signal corresponds to one pole of the magnet passing through the sensor, so the frequency of the pulse signal is proportional to the speed of the motor. At the same time, the direction of the motor can be determined by comparing the relative phase difference of the two signals. When the motor rotates forward, one signal will be generated before the other signal; when the motor rotates reversely, the phase difference is the opposite. By detecting the change in this phase difference, the direction of the motor can be determined.

[0043] See also Figures 5 to 7 In this embodiment, the dual-channel Hall signal and the single-channel Hall waveform are as follows: Figure 6As shown in the figure, MCU is a signal processor, that is, a single-chip microcomputer in the Hall circuit; Hall1 and Hall2 are dual-channel Hall signals output by the Hall sensing circuit, and Hall_OUT is a Hall signal obtained after Hall1 and Hall2 are re-encoded by the single-chip microcomputer and the Hall signal synthesis circuit. First, the magnetic field changes of the motor magnetic ring are collected by two Hall sensors and converted into corresponding electrical signals Hall1 and Hall2. In order to ensure the stability of the signal, Hall1 and Hall2 will be sent to the first-order RC filter for filtering. Subsequently, after AD conversion, the single-chip microcomputer (MCU) can read the level values ​​of these electrical signals in real time. When judging whether the motor has started running, the single-chip microcomputer will sample the level state of the two Hall signals. If the current level of any signal is different from the previous level state, it is determined that the motor has started running. Since the two Hall sensors are arranged orthogonally in space, the level change sequence of the two Hall signals shows specific differences during the operation of the motor. Specifically: When the motor rotates forward, the signal change sequence of Hall1 and Hall2 is: 0,0 → 1,0 → 1,1 → 0,1. When the motor rotates reverse, the signal change sequence is: 0,0 → 0,1 → 1,1 → 1,0.

[0044] Through this change sequence, the MCU can determine the forward and reverse state of the motor. Furthermore, when the motor rotates forward, the MCU controls the level of the Hall_OUT signal to jump between 0-5V through the P1-P2 port and the signal synthesis circuit. When the motor reverses, the MCU uses the P3-P6 port and the signal synthesis circuit to make the level of the Hall_OUT signal jump between 1-3V.

[0045] from Figure 6 It can be observed that both Hall1 and Hall2 show periodic square wave changes, and the period of this square wave is directly related to the motor speed. When the motor rotates forward, the Hall1 signal changes before Hall2; conversely, when the motor rotates reversely, the Hall2 signal changes before Hall1. Furthermore, the Hall_OUT signal indicates the direction of the motor through the voltage amplitude of the square wave. Specifically, when the motor rotates forward, the voltage amplitude of Hall_OUT will vary in the range of 0~5V; and when the motor rotates reversely, its voltage amplitude will vary in the range of 1~3.3V. In addition, the Hall_OUT signal still retains the frequency of the square wave to represent the motor speed, and at the same motor speed, the signal frequency of Hall_OUT is twice the frequency of the Hall1 and Hall2 signals.

[0046] See also Figure 7 The signal conversion circuit provided in this embodiment, the signal processing unit also includes a signal processor and a signal synthesis circuit, the signal processor and the signal synthesis circuit are connected, the signal processor is used to extract the speed information and steering information in the first electrical signal, and convert the steering information into a signal amplitude, and convert the speed information into a pulse, and output it to the signal synthesis circuit after compression, mixing and encoding. The signal synthesis circuit includes a plurality of composite triodes, the composite triodes include NPN and PNP type triodes, the collector of the NPN type triode is used to connect to the power supply, the collector of the PNP type triode is used to ground, and the emitters of the NPN and PNP type triodes are used to connect to the output port; wherein the plurality of composite triodes include a first composite triode for controlling the output of the signal when the driving component rotates forward, and a second composite triode and a third composite triode for controlling the output of the signal when the driving component rotates reversely.

[0047] In this embodiment, the signal synthesis circuit is as follows: Figure 7 As shown in the figure, MCU is a signal processor, that is, a single chip microcomputer in the Hall circuit; Q1, Q2, and Q3 are the first compound triode, the second compound triode, and the third compound triode, respectively, and each compound triode contains an NPN type and a PNP type crystal triode. In terms of connection: the P1 and P2 ports of the microcontroller are connected to the NPN base and PNP base of Q1 respectively; the P3 and P4 ports are connected to the NPN base and PNP base of Q2 respectively; the P5 and P6 ports are connected to the NPN base and PNP base of Q3 respectively; the two ends of resistor R16 are connected to the power supply VCC and the NPN collector of Q1; the two ends of resistor R17 are connected to Hall_OUT and the PNP emitter of Q1; the two ends of resistor R18 are connected to the power supply VCC and the NPN collector of Q2; the two ends of resistor R19 are connected to the ground line GND and the PNP collector of Q2; the two ends of resistor R20 are connected to the power supply VCC and the NPN collector of Q3; the two ends of resistor R21 are connected to the ground line GND and the PNP collector of Q3; the emitter of NPN in Q2 and the emitter of PNP are connected to Hall_OUT together; the emitter of NPN in Q3 and the emitter of PNP are connected to Hall_OUT together.

[0048] When the motor rotates forward, the MCU ports P1 and P2 control the switch states of the NPN and PNP transistors of Q1 by alternating high and low levels, so that Hall_OUT outputs a square wave. The time for the level to change alternately is the period of the Hall_OUT signal. When P1 is low and P2 is high, the NPN and PNP transistors of Q1 are in the cut-off state. Due to the presence of the pull-up resistor at the wiring port of the Hall circuit, the Hall_OUT output is a 5V high level. When P1 is high and P2 is low, the NPN and PNP transistors of Q1 are in a saturated state, and Hall_OUT outputs a 0V low level. When the motor reverses, P3 is high and P4 is low, so that the NPN and PNP transistors of Q2 are in a saturated state, R18 and R19 form a voltage divider circuit to make Hall_OUT output a 3.3V low level, P5 is high and P6 is low, so that the NPN and PNP transistors of Q3 are in a saturated state, R20 and R21 form a voltage divider circuit to make Hall_OUT output a 1V low level.

[0049] It should be noted that, in this embodiment, the pressure detection module is mainly used to detect the resistance of the electric lifting table during operation, that is, to detect the external obstacles or resistance encountered by the desktop during the lifting process. The pressure detection module can react quickly when encountering resistance and provide a preliminary judgment of encountering resistance. It is the main resistance detection method for the electric lifting table. In addition, the drive detection module can also serve as an auxiliary reference to provide more comprehensive support for encountering resistance detection. The drive detection module is mainly used to obtain the motor speed steering signal of the electric lifting table. When the pressure detection module sends an encountering resistance signal, the drive detection module can provide key motor status information as a reference for judging the source and nature of the resistance. For example, when the pressure detection module detects resistance, if the drive detection module simultaneously monitors that the motor speed has dropped significantly or even stopped, this information can be mutually verified with the encountering resistance signal, thereby further confirming that the lifting table has indeed encountered an obstacle or resistance, rather than a false trigger.

[0050] By simultaneously analyzing the output signals of the pressure detection module and the drive detection module, the signal processing unit can more accurately determine the actual working status of the electric lifting table, thereby reducing misjudgment and improving detection accuracy and system reliability. This application does not limit the specific signal acquisition module for resistance judgment.

[0051] See also Figures 8 to 10 The present application also provides a method for determining an obstruction, using the above-mentioned signal conversion circuit, and further comprising the following steps: Step 102, generating a corresponding electrical signal according to the deformation degree of the target area, and filtering and amplifying the electrical signal to form a second electrical signal; Among them, the piezoelectric sensor is installed in the weak part of the motor structure. When the motor is running, the piezoelectric sensor is subjected to force to generate an electrical signal. During normal operation, the force is small and the signal amplitude is low; when encountering resistance, the piezoelectric sensor is subjected to a sudden increase in force and the signal amplitude increases rapidly.

[0052] Filtering and amplification processing refers to filtering the piezoelectric sensor signal first to remove high-frequency noise and interference to ensure the purity of the signal. Then the weak piezoelectric sensor signal is amplified by an operational amplifier (such as IC1A) to form a second electrical signal for subsequent sampling and analysis.

[0053] Step 104: continuously sample the second electrical signal to obtain continuous sampling signals CN1[M], CN2[M], ..., CN n [M]; Step 106, continuously sampling signals CN1[M], CN2[M], ..., CN n [M] Perform Kalman filtering; Among them, CN represents the continuous sampling signal set of the piezoelectric film signal, that is, the electrical signal collected by the pressure detection module, and the digital signal after AD conversion. n represents the nth piezoelectric film signal, because in this embodiment, multiple piezoelectric film sensors may be installed in multiple weak areas of the electric lifting table. Each piezoelectric film corresponds to a signal channel, and n refers to a specific piezoelectric film signal. M represents the signal value of the Mth sampling. Continuously sampled signals refer to the system collecting the electrical signals of the piezoelectric film multiple times within a period of time, and each collected signal value will be stored as a data point. CN n [M] represents the Mth sampling signal value of the nth piezoelectric patch. This symbol is used to describe the continuous sampling process of multiple piezoelectric patch signals by the system. Each piezoelectric patch signal will be sampled multiple times to form a set of continuous signal data for subsequent analysis and processing.

[0054] The signal after filtering and amplification CN n [M] Digital processing is performed through an AD converter. The microcontroller samples the digitized signal multiple times continuously to obtain a set of continuous signal data CN. Continuous sampling can capture the dynamic change process of the piezoelectric sensor signal and reflect the real-time stress of the motor structure.

[0055] In step 106, the sampled signal data CN n [M] performs denoising. Kalman filtering is a recursive algorithm that can estimate the optimal state in a dynamic system and improve the accuracy and stability of the sampled signal by eliminating random noise and errors.

[0056] Step 108, when the driving component is in operation, if CN in the continuous sampling signal n+1 [M] and CNn [M] The difference after Kalman filtering is greater than the first preset value, or CN in the continuous sampling signal n [M]~ CN n+c [M] If the number of values ​​greater than the first threshold exceeds a second preset value, it is determined that the motor structure corresponding to the piezoelectric sensor encounters resistance.

[0057] See also Fig. 9 , Fig. 9 It indicates that any piezoelectric piece in the multi-channel strain signal detection circuit is abnormal, that is, an obstruction signal is output, wherein Y indicates that the determination of any piezoelectric piece being abnormal is passed.

[0058] See also Fig.10 , where when the motor is in the running state (rising or falling), the following two judgment conditions are set based on the data set CN of the sampled piezoelectric sensor signal, where Y indicates a passed judgment and N indicates a failed judgment: The difference between the maximum value and the minimum value is greater than the first preset value a: This indicates that the piezoelectric sensor signal fluctuated significantly in a short period of time, reflecting that the motor encountered greater resistance.

[0059] The number of values ​​greater than the first threshold value b exceeds the second preset value c: This indicates that there are a large number of higher amplitudes in the signal, further confirming that the force on the piezoelectric sensor has increased.

[0060] The difference between the motor rising and falling states: Under different operating states, the force characteristics of the motor are different, so different preset values ​​(a, b, c) need to be set to adapt to different working conditions. In this embodiment, a, b, c are the amplitude constant threshold and quantity constant threshold set when the motor is in the rising state, and d, e, f are the amplitude constant threshold and quantity constant threshold set when the motor is in the falling state.

[0061] By setting a variety of judgment conditions, the system can sensitively judge whether the motor encounters resistance according to actual signal changes. Dynamically adjust the judgment threshold under different operating conditions to improve the accuracy and adaptability of resistance detection and avoid misjudgment and missed judgment.

[0062] The present application also provides an electric lifting table, including the above-mentioned signal conversion circuit, and also includes a drive component and a control box. The control box is used to obtain the detection results output by the signal processing unit and adjust the movement state of the drive component according to the detection results.

[0063] The Hall sensor in the signal conversion circuit detects the speed and direction of the drive component, and generates a recognizable signal through the signal synthesis circuit and outputs it to the signal processing unit. The pressure detection module can detect the resistance or resistance signal encountered by the electric lift table during operation, and determine whether it encounters an obstacle through the signal processing unit. The signal conversion circuit ensures that the operating status of the lift table can be monitored in real time and triggers the corresponding response signal when an abnormality is encountered.

[0064] The control box receives the detection results output by the signal processing unit, such as speed, steering information, and resistance signals. When an abnormality is detected (such as encountering resistance or obstacles), the control box can immediately instruct the drive component to pause or change direction, thereby protecting the safety of the lift table and the user. Through the coordination of the control box, the electric lift table can achieve intelligent control, which can not only realize basic lifting functions, but also has automatic anti-pinch, anti-collision and other safety functions.

[0065] Under the command of the control box, the drive component can perform lifting and lowering actions according to demand, realizing the basic functions of the lift table. Through the signal conversion circuit, when the drive component encounters resistance or abnormal conditions, it can adjust the movement state according to the feedback of the control box to avoid possible damage or safety hazards. The movement state of the drive component can not only be detected, but also adjusted as needed, which enhances the safety and intelligence of the electric lift table.

[0066] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A signal conversion circuit, arranged on a driving component of an electric lifting table, characterized in that: It includes a detection unit and a signal processing unit, wherein: The detection unit includes a drive detection module and a pressure detection module, wherein the drive detection module is used to obtain a first electrical signal of a drive component in the electric lift table, and the pressure detection module is used to obtain a second electrical signal of a target area in the electric lift table; The output ends of the drive detection module and the pressure detection module are respectively connected to the input end of the signal processing unit. The signal processing unit is used to convert the first electrical signal into a speed steering signal, and convert the second electrical signal into a resistance signal. The signal processing unit also has an output end for outputting the speed steering signal and the resistance signal.

2. The signal conversion circuit according to claim 1, characterized in that: The pressure detection module includes a plurality of strain signal detection circuits, and the plurality of strain signal detection circuits are arranged in a plurality of target areas of the driving component to form a detection network together; The plurality of strain signal detection circuits are connected in series or in parallel.

3. The signal conversion circuit according to claim 1, characterized in that: The drive detection module includes a plurality of drive signal detection circuits, and the first electrical signal is a Hall signal output by the drive signal detection circuit.

4. The signal conversion circuit according to claim 1, characterized in that: The signal processing unit includes a signal processor and a signal synthesis circuit, and the signal processor is connected to the signal synthesis circuit. The signal processor is used to extract the rotation speed information and steering information in the first electrical signal, and convert the steering information into a signal amplitude, and convert the rotation speed information into a pulse, and then compress, mix and encode it and output it to the signal synthesis circuit.

5. The signal conversion circuit according to claim 2, characterized in that: The strain signal detection circuit includes a pressure sensor and a signal filtering and amplifying circuit. The pressure sensor is arranged at a structural deformation-prone position of the driving component to generate a piezoelectric signal related to the deformation; the signal filtering and amplifying circuit is used to filter and amplify the piezoelectric signal.

6. The signal conversion circuit according to claim 5, characterized in that: The pressure detection module also includes a DC coupling capacitor and an AC coupling capacitor. The DC coupling capacitor is used to generate a DC bias at the input end of the signal filtering and amplifying circuit, and the AC coupling capacitor is used to suppress differential mode interference generated by the piezoelectric sensor.

7. The signal conversion circuit according to claim 3, characterized in that: The driving signal detection circuit includes a Hall sensor and a filter circuit. The Hall sensor is used to generate a Hall signal following the change of the magnetic field of the driving component. The Hall signal is output via the filter circuit.

8. The signal conversion circuit according to claim 7, characterized in that: The Hall sensors are arranged in pairs at the periphery of the driving component, and the pair of Hall sensors are orthogonally arranged on the same spatial plane.

9. A method for determining an obstacle, using the signal conversion circuit according to any one of claims 1 to 8, characterized in that: The following steps are also included: Generate a corresponding electrical signal according to the deformation degree of the target area, and filter and amplify the electrical signal to form a second electrical signal; The second electrical signal is continuously sampled to obtain continuous sampling signals CN1[M], CN2[M], ..., CN n [M]; The continuous sampling signals CN1[M], CN2[M], ..., CN n [M] Perform Kalman filtering; When the driving component is in operation, if CN in the continuous sampling signal n+1 [M] and CN n [M] The difference after Kalman filtering is greater than the first preset value, or the continuous sampling signal CN n [M]~ CN n+c If the number of values ​​in [M] that are greater than the first threshold value exceeds a second preset value, it is determined that the motor structure in the target area encounters an obstruction.

10. An electric lifting table, characterized in that: The signal conversion circuit comprises the signal conversion circuit as described in any one of claims 1 to 8, and further comprises a driving component and a control box, wherein the control box is used to obtain the detection result output by the signal processing unit and adjust the motion state of the driving component according to the detection result.

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