An encounter resistance backoff method and system based on electrically controlled current sampling and lifting equipment

Abstract

This invention provides a method, system, and lifting device for motor resistance reversal, relating to the field of motor control technology. The method includes: Step S1, acquiring the real-time current of the motor during stable operation; Step S2, calculating the similarity between the real-time current of the current cycle and the real-time current of the previous cycle, and determining whether the similarity is within a preset similarity threshold range: if yes, return to step S2; if no, determine that the motor is encountering resistance and control the motor to reverse and reverse. The beneficial effect is that by acquiring the motor's real-time current periodically and then comparing the similarity of the current between adjacent cycles to determine whether resistance has occurred, the possibility of false alarms due to power supply voltage fluctuations and interference factors is reduced; and equipment costs are effectively controlled.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a method, system and lifting device for obstacle detection and reversal based on electronic control current sampling. Background Technology

[0002] In modern office environments, height-adjustable desks, as an important piece of office equipment, are widely welcomed for their flexible height adjustment and adaptability to different user needs. To achieve the height adjustment function of a height-adjustable desk, the motor drive system is one of its core components. During the motor-driven operation of the height-adjustable desk, the motor's resistance-reverse technology is particularly important to ensure smooth operation and user safety.

[0003] In existing technologies, most motor-driven obstacle-induced retraction mechanisms for height-adjustable desks employ sensor detection solutions. These solutions detect obstruction by installing sensors near the desk legs or motor. These sensors, such as six-axis sensors or strain gauges, can monitor the forces acting on the legs or motor in real time. When the desk encounters an obstacle, the forces on the legs or motor change, and the sensors detect this change, triggering the retraction mechanism. However, this approach requires external sensors, increasing costs and demanding sophisticated manufacturing processes. The sensor's installation location, accuracy, and signal processing all require strict control to ensure the accuracy and reliability of the detection results. Therefore, developing a more stable, reliable, and cost-effective motor-driven obstacle-induced retraction technology is crucial for improving the performance and user experience of height-adjustable desks. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a method for motor resistance back-off, comprising:

[0005] Step S1: Obtain the real-time current of the motor when it is in a stable operating state;

[0006] Step S2: Calculate the similarity between the real-time current of the current cycle and the real-time current of the previous cycle, and determine whether the similarity is within a preset similarity threshold range.

[0007] If so, return to step S2;

[0008] If not, then determine that the motor is resisting and control the motor to reverse and retract.

[0009] Preferably, step S1 includes:

[0010] Step S11: Determine whether the electronic control voltage received by the motor is within a preset voltage stability range, or whether the motor speed is within a preset speed stability range.

[0011] If so, it is determined that the motor has entered a stable operating state, and then proceeds to step S12;

[0012] If not, return to step S11;

[0013] Step S12: Obtain the real-time current of the motor.

[0014] Preferably, step S2 includes:

[0015] Step S21: Obtain the real-time current curve of the current cycle based on the real-time current processing of the current cycle, and obtain the real-time current curve of the previous cycle based on the real-time current processing of the previous cycle. Here, the cycle refers to one rotation of the motor.

[0016] Step S22: Calculate the similarity between the real-time current curve of the current cycle and the real-time current curve of the previous cycle, and determine whether the similarity is within a preset similarity threshold range.

[0017] If so, return to step S21;

[0018] If not, then determine that the motor is resisting and control the motor to reverse and retract.

[0019] Preferably, step S2 includes:

[0020] Step S21: Take multiple current values ​​from the real-time current of the previous cycle and add them to the cached current sequence according to a preset step size. Here, the cycle refers to one rotation of the motor.

[0021] Step S22: Take multiple current values ​​from the real-time current of the current cycle according to the preset step size and add them to the real-time current sequence, where the cycle refers to one rotation of the motor.

[0022] Step S23: Take the current values ​​with the same position from the cached current sequence and the real-time current sequence and calculate the corresponding ratio.

[0023] Step S24: Take the average of all the ratios as the similarity and determine whether the similarity is within the preset similarity threshold range.

[0024] The present invention also provides an electrical resistance back-off system, comprising:

[0025] MCU, the MCU being used to execute the circuit resistance back-off method as described above;

[0026] The motor control circuit has the control signal output terminal of the MCU connected to the control signal receiving terminal of the motor control circuit, and the control signal output terminal of the motor control circuit electrically connected to the positive and negative terminals of the motor.

[0027] A current sampling circuit is provided, wherein the sampling terminal of the current sampling circuit is connected to the current sampling terminal of the motor control circuit, and the current data uploading terminal of the current sampling circuit is connected to the current data receiving terminal of the MCU.

[0028] Preferably, the current sampling circuit includes:

[0029] A current sampling chip, wherein the third and fifth pins of the current sampling chip are connected to the current sampling terminal of the motor control circuit;

[0030] The rising sampling circuit has its current output terminal connected to the first pin of the current sampling chip, its current input terminal connected to the second pin of the rising current sampling chip, and its current data upload terminal connected to the current data receiver of the MCU.

[0031] A falling sampling circuit is provided, wherein the current output terminal of the falling sampling circuit is connected to the seventh pin of the current sampling chip, the current input terminal of the falling sampling circuit is connected to the sixth pin of the falling current sampling chip, and the current data upload terminal of the falling sampling circuit is connected to the current data receiver of the MCU.

[0032] Preferably, both the rising sampling circuit and the falling sampling circuit include:

[0033] A sampling resistor, one end of which is connected to the current data receiving terminal of the MCU, and the other end of which is connected to one end of a first resistor and one end of a first capacitor;

[0034] The second resistor has one end connected to the other end of the first resistor and one end of the third resistor, and the other end of the third resistor and the other end of the first capacitor are grounded.

[0035] One end of the second resistor serves as the current output terminal, and the other end of the second resistor serves as the current input terminal.

[0036] Preferably, the control signal output terminal of the MCU includes a high-frequency left turn signal terminal, a low-frequency left turn signal terminal, a high-frequency right turn signal terminal, and a low-frequency right turn signal terminal;

[0037] The motor control circuit includes:

[0038] A left-turn drive circuit, wherein the high-frequency signal receiving end of the left-turn drive circuit is connected to the left-turn high-frequency signal end, the low-frequency signal receiving end of the left-turn drive circuit is connected to the left-turn low-frequency signal end, and the motor connection end of the left-turn drive circuit is connected to the positive terminal of the motor.

[0039] A right-turn drive circuit, wherein the high-frequency signal receiving end of the right-turn drive circuit is connected to the right-turn high-frequency signal end, the low-frequency signal receiving end of the right-turn drive circuit is connected to the right-turn low-frequency signal end, and the motor connection end of the right-turn drive circuit is connected to the negative terminal of the motor.

[0040] The current sampling terminal of the left turn drive circuit and the current sampling terminal of the right turn drive current are connected to one end of the fourth resistor and the fifth resistor. The other end of the fifth resistor is grounded. The other end of the fourth resistor is connected to one end of the sixth resistor, one end of the second capacitor, one end of the third capacitor, and the sampling terminal of the current sampling circuit. The other ends of the sixth resistor, the second capacitor, and the third capacitor are grounded.

[0041] Preferably, both the left-turn drive circuit and the right-turn drive circuit include:

[0042] The driver chip has a second pin serving as the high-frequency signal receiver and a third pin serving as the low-frequency signal receiver.

[0043] The seventh resistor has one end connected to the first pin of the driver chip, and the other end connected to the positive terminal of the first diode. The negative terminal of the first diode is connected to the eighth pin of the driver chip and one end of the fourth capacitor. The other end of the fourth capacitor is connected to the sixth pin of the driver chip.

[0044] The first field-effect transistor has its drain connected to the power supply, and its gate connected to one end of the fifth capacitor, one end of the eighth resistor, one end of the ninth resistor, and the positive terminal of the second diode. The negative terminal of the second diode is connected to the other end of the ninth resistor and the seventh pin of the driver chip.

[0045] The second field-effect transistor has its drain connected to the other end of the fifth capacitor, the other end of the eighth resistor, and the other end of the fourth capacitor. Its gate is connected to the fifth pin of the driver chip. A tenth resistor is connected between the drain and source of the second field-effect transistor.

[0046] A sixth capacitor is connected between the first and fourth pins of the driver chip.

[0047] The source of the second field-effect transistor serves as the current sampling terminal of the left-turn drive circuit and the right-turn drive circuit, and the drain of the second field-effect transistor serves as the motor connection terminal of the left-turn drive circuit and the right-turn drive circuit.

[0048] The present invention also provides a lifting device, wherein the lifting device is equipped with a control box, and the control box integrates the above-mentioned motor resistance retraction system;

[0049] The lifting legs of the lifting device are equipped with motors, and the motor control circuit in the motor resistance retraction system is electrically connected to the positive and negative terminals of the motor.

[0050] The above technical solution has the following advantages or beneficial effects:

[0051] 1. The obstacle encounter and back-off method provided in this invention collects the real-time current of the motor according to the cycle, and then compares the similarity of the current between adjacent cycles to determine whether an obstacle has been encountered, thereby reducing the possibility of false alarms caused by interference factors such as power supply voltage fluctuations, changes in the internal resistance of the motor, different gear intervals, and different thicknesses of table legs.

[0052] 2. The obstacle detection and retraction system provided by this invention only uses the current sampling circuit that all motors have, without setting up additional sensors or strain gauges, which effectively controls equipment costs. Attached Figure Description

[0053] Figure 1 This is a flowchart illustrating a method for obstacle detection and back-off based on electronically controlled current sampling, as shown in some embodiments of the present invention.

[0054] Figure 2 This is a schematic diagram of a sub-process of step S1 in some embodiments of the present invention;

[0055] Figure 3 In some embodiments of the present invention, the normal operating current curve of the motor is shown.

[0056] Figure 4 In some embodiments of the present invention, the current curve of the motor when encountering resistance and retracting is shown.

[0057] Figure 5 This is a schematic diagram of a sub-process of step S2 in some embodiments of the present invention;

[0058] Figure 6 The pin diagram of the MUC is shown in some embodiments of the present invention.

[0059] Figure 7 The circuit diagram of the current sampling circuit is shown in some embodiments of the present invention;

[0060] Figure 8 This is a circuit diagram of a motor control circuit in some embodiments of the present invention;

[0061] Figure 9 The above are schematic diagrams of the lifting device in some embodiments of the present invention. Detailed Implementation

[0062] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment; other embodiments that conform to the spirit of the present invention may also fall within the scope of the present invention.

[0063] In some embodiments of the present invention, based on the above-mentioned problems existing in the prior art, a method for obstacle detection and back-off based on electronically controlled current sampling is provided, such as... Figure 1 As shown, it includes:

[0064] Step S1: Obtain the real-time current of the motor when it is in a stable operating state;

[0065] Step S2: Calculate the similarity between the real-time current of the current cycle and the real-time current of the previous cycle, and determine whether the similarity is within a preset similarity threshold range.

[0066] If so, return to step S2;

[0067] If not, then determine that the motor is resisting and control the motor to reverse and retract.

[0068] In a preferred embodiment, such as Figure 2 As shown, step S1 includes:

[0069] Step S11: Determine whether the electronic control voltage received by the motor is within a preset voltage stability range, or whether the motor speed is within a preset speed stability range.

[0070] If so, the motor is determined to have entered a stable operating state, and then proceeds to step S12;

[0071] If not, return to step S11;

[0072] Step S12: Obtain the real-time current of the motor.

[0073] Specifically, such as Figure 3The diagram shows the normal operating current curves of the motor. From top to bottom, these are the motor current curve, the electrical control voltage curve received by the motor, and the motor speed curve. It can be seen that the electrical control voltage curve gradually increases in the initial stage, and the motor current and speed curves increase accordingly. After the electrical control voltage curve reaches a pre-set stable voltage range (with slight fluctuations within a certain range), the motor speed curve also reaches a pre-set stable speed range (with slight fluctuations within a certain range). The motor current curve exhibits a certain regularity in its change. This is because the gears in the motor reducer cannot be precisely spaced evenly during manufacturing, resulting in different resistance values ​​at each point during one revolution of the motor. At a constant speed, the motor encounters different resistances, resulting in different current outputs. Since the reduction gear returns to its initial position after one revolution, the motor current exhibits periodic changes. This periodic current fluctuation makes traditional methods of detecting the rate of change of current inaccurate in determining the motor's resistance. Figure 3 The middle section shows the process of the motor driving the height-adjustable table upwards. The motor current curve shows a decreasing trend because during the painting process of the table legs, the paint flows downwards, gradually thickening near the bottom of the table legs while the paint at the top of the legs is relatively thin. Therefore, during the upward movement, the resistance that the motor needs to overcome gradually decreases, resulting in a corresponding decrease in current. Conversely, the current trend during the downward movement can be deduced similarly. The decreasing trend of the motor current curve here is observed throughout the entire movement of the table legs from bottom to top (or from top to bottom). In contrast, the previously mentioned periodic change in motor current is observed during each revolution of the motor. The two observations differ.

[0074] like Figure 4 The image shows the current curve of the motor when it encounters an obstacle and reverses. When no obstacle is encountered, the current exhibits a certain regularity after the motor starts and reaches a constant speed. However, when an obstacle is encountered, the current curve suddenly rises, deviating significantly from the previous regularity. When the motor detects an obstacle, the control output is immediately disconnected, and after the motor stops, the output is reversed to allow the motor to reverse, minimizing damage from the collision.

[0075] To address this periodic current fluctuation, this embodiment collects the motor's real-time current periodically during stable operation. The period refers to one rotation of the motor. The real-time current for the current period is the current continuously collected during the motor's current rotation. The similarity of currents between adjacent periods is then compared to determine if an obstruction has occurred. If an obstruction is encountered, an error message will appear. Figure 4In the event of a sudden increase in current, the calculated similarity is far beyond the set similarity threshold range, which can accurately determine the obstruction situation and reduce the possibility of false alarms caused by current fluctuations due to interference factors such as power supply voltage fluctuations, changes in motor internal resistance, different gear intervals, and different table leg thicknesses.

[0076] Furthermore, during the use of the motor, as the height-adjustable table is used for a longer period of time, hardware wear and tear will occur, such as wear on the gears of the motor reducer. However, structural wear only affects the current curve of a single cycle and does not affect the periodic change of the current, thus not affecting the resistance detection of this method.

[0077] In a preferred embodiment, step S2 includes:

[0078] Step S21: Obtain the real-time current curve of the current cycle based on the real-time current processing of the current cycle, and obtain the real-time current curve of the previous cycle based on the real-time current processing of the previous cycle. Here, the cycle refers to one rotation of the motor.

[0079] Step S22: Calculate the similarity between the real-time current curve of the current cycle and the real-time current curve of the previous cycle, and determine whether the similarity is within the preset similarity threshold range.

[0080] If so, return to step S21;

[0081] If not, then determine that the motor is resisting and control the motor to reverse and retract.

[0082] Specifically, in this embodiment, the similarity between current curves can be compared to determine whether resistance has been encountered. Various similarity algorithms exist, such as the common Euclidean distance algorithm, Pearson correlation coefficient algorithm, and Manhattan distance algorithm. By monitoring and analyzing changes in the current curves in real time, detection can be performed at an early stage when the motor encounters significant resistance or a fault. This helps prevent more serious damage or failure, thereby improving the reliability and stability of the system. The current curve reflects the motor's load and dynamic performance during operation. By comparing the current curves of two cycles, it is possible to more accurately determine whether the motor has encountered abnormal resistance. This method is more comprehensive and reliable than monitoring a single current value.

[0083] In a preferred embodiment, such as Figure 5 As shown, step S2 includes:

[0084] Step S21: Take multiple current values ​​from the real-time current of the previous cycle and add them to the cached current sequence according to a preset step size. Here, the cycle refers to one rotation of the motor.

[0085] Step S22: Take multiple current values ​​from the real-time current of the current cycle according to a preset step size and add them to the real-time current sequence. Here, the cycle refers to one rotation of the motor.

[0086] Step S23: Take the current values ​​with the same position from the cached current sequence and the real-time current sequence and calculate the corresponding ratio.

[0087] Step S24: Use the average of all ratios as the similarity score, and determine whether the similarity score is within the preset similarity threshold range.

[0088] If so, return to step S21;

[0089] If not, then determine that the motor is resisting and control the motor to reverse and retract.

[0090] Specifically, besides the impact of motor structural components on the current, the tightness of the table leg's tubing and the changes in motor efficiency caused by temperature rise also affect the current curve. However, these external interferences are not abrupt but rather a slow, gradual process. Therefore, this invention uses similar current data (current from the previous cycle) for similarity calculations to minimize such interference.

[0091] The similarity calculation process includes: taking the current data every 1ms within two cycles (the current cycle and the previous cycle) and putting it into the cached current sequence A and the real-time current sequence B.

[0092] Calculate B[1] / A[1], B[2] / A[2], B[3] / A[3]... and take the average value as the similarity. The similarity should be within the set similarity threshold range (0.9-1.1 in this example). If it is not within this range, the motor will be judged to be blocked and the motor will be controlled to reverse and retract.

[0093] This invention also provides an obstacle detection and back-off system based on electronically controlled current sampling, such as... Figure 6-9 As shown, it includes:

[0094] The MCU is used to execute the obstacle avoidance and back-off method described above.

[0095] In the motor control circuit, the control signal output terminal of the MCU is connected to the control signal receiving terminal of the motor control circuit, and the control signal output terminal of the motor control circuit is electrically connected to the positive and negative terminals of the motor.

[0096] The current sampling circuit has its sampling terminal connected to the current sampling terminal of the motor control circuit, and its current data upload terminal connected to the current data receiver terminal of the MCU.

[0097] In a preferred embodiment, such as Figure 7 As shown, the current sampling circuit includes:

[0098] The current sampling chip U1 has its third and fifth pins connected to the current sampling terminal MI-I of the motor control circuit.

[0099] The rising sampling circuit 100 has its current output terminal connected to the first pin of the current sampling chip U1, its current input terminal connected to the second pin of the rising current sampling chip U1, and its current data upload terminal MI-I-AD-UP connected to the current data receiver terminal MI-I-AD-UP of the MCU.

[0100] The current output terminal of the downsampling circuit 200 is connected to the seventh pin of the current sampling chip U1, the current input terminal of the downsampling circuit 200 is connected to the sixth pin of the downsampling current sampling chip 200, and the current data upload terminal MI-I-AD-DOWN of the downsampling circuit 200 is connected to the current data receiver terminal MI-I-AD-DOWN of the MCU.

[0101] In a preferred embodiment, such as Figure 7 As shown, the structures of the rising sampling circuit 100 and the falling sampling circuit 200 are the same, both including:

[0102] The sampling resistor R0 is connected to the current data receiving terminal of the MCU at one end, and the other end of the sampling resistor R0 is connected to one end of the first resistor R1 and one end of the first capacitor C1.

[0103] The second resistor R2 is connected to the other end of the first resistor R1 and the other end of the third resistor R3. The other end of the third resistor R3 and the other end of the first capacitor C1 are grounded.

[0104] One end of the second resistor R2 serves as the current output terminal, and the other end of the second resistor R2 serves as the current input terminal.

[0105] Specifically, the sampling circuit accurately collects the motor's current data and uploads it to the MCU for processing, thereby achieving real-time monitoring of the motor's operating status. This real-time monitoring ensures more precise control of the motor by the system, improving the overall system accuracy. The sampling circuit's role is particularly significant in applications requiring high-precision control, such as the obstacle detection and reversal function of an electric height-adjustable desk.

[0106] The sampling circuit provides real-time feedback of motor current information, enabling the MCU to adjust and control the motor promptly based on this information. This feedback mechanism helps enhance system stability and prevents system crashes or malfunctions caused by abnormal motor current. Simultaneously, the sampling circuit can also provide early warnings for motor overload, short circuits, and other faults, further improving system reliability.

[0107] In the sampling circuit, through reasonable circuit design and component selection, accurate sampling and processing of motor current can be achieved, thereby avoiding unnecessary energy loss. This optimization helps improve power supply efficiency, making the system more energy-efficient and environmentally friendly during operation.

[0108] In a preferred embodiment, the control signal output terminals of the MCU include a high-frequency left turn signal terminal MI-HS-L, a low-frequency left turn signal terminal MI-LS-L, a high-frequency right turn signal terminal MI-HS-R, and a low-frequency right turn signal terminal MI-LS-R;

[0109] like Figure 8 As shown, the motor control circuit includes:

[0110] The left-turn drive circuit 300 has a high-frequency signal receiving terminal MI-HS-L connected to the left-turn high-frequency signal terminal MI-HS-L, a low-frequency signal receiving terminal MI-LS-L connected to the left-turn low-frequency signal terminal MI-LS-L, and a motor connection terminal MI+ connected to the positive terminal of the motor.

[0111] The right turn drive circuit 400 has a high-frequency signal receiving terminal MI-HS-R connected to the right turn high-frequency signal terminal MI-HS-R, a low-frequency signal receiving terminal MI-LS-R connected to the right turn low-frequency signal terminal MI-LS-R, and a motor connection terminal MI- connected to the negative terminal of the motor.

[0112] The current sampling terminal of the left turn drive circuit 300 and the current sampling terminal of the right turn drive current 400 are connected to one end of the fourth resistor R4 and the fifth resistor R5. The other end of the fifth resistor R5 is grounded. The other end of the fourth resistor R4 is connected to one end of the sixth resistor R6, one end of the second capacitor C2, one end of the third capacitor C3 and the sampling terminal of the current sampling circuit, respectively. The other ends of the sixth resistor R6, the second capacitor C2 and the third capacitor C3 are grounded.

[0113] Specifically, the motor control circuit receives control signals from the MCU to precisely control the motor's operating state. For example, the left-turn drive circuit and the right-turn drive circuit receive high-frequency and low-frequency signals for left and right turns, respectively, thereby achieving precise control of the motor's left and right turns. This precise control helps ensure that the motor can reverse in time when encountering obstacles, avoiding damage or safety hazards.

[0114] The motor control circuit is designed to enable the system to respond quickly to MCU control signals. When the MCU issues a control signal, the motor control circuit can rapidly translate it into actual control of the motor, thereby improving the system's response speed. This rapid response capability is particularly important for obstacle detection and back-off systems, as it allows for quick adjustments to the motor's operating state, ensuring system stability and safety.

[0115] The motor control circuit includes a current sampling terminal, which, through the connection of components such as resistors and capacitors, enables precise sampling and processing of the motor current. This sampling and processing helps the MCU monitor the motor's operating status in real time and perform more precise control of the motor based on the current data. At the same time, through proper circuit design and component selection, unnecessary energy loss can be avoided, improving power supply efficiency.

[0116] In a preferred embodiment, such as Figure 8 As shown, the left-turn drive circuit 300 and the right-turn drive circuit 400 have the same structure, both including:

[0117] The driver chip U2 has its second pin as a high-frequency signal receiver and its third pin as a low-frequency signal receiver.

[0118] The seventh resistor R7 is connected to the first pin of the driver chip U2 at one end and to the positive terminal of the first diode D1 at the other end. The negative terminal of the first diode D1 is connected to the eighth pin of the driver chip U2 and one end of the fourth capacitor C4. The other end of the fourth capacitor C4 is connected to the sixth pin of the driver chip U2.

[0119] The drain of the first field-effect transistor Q1 is connected to the power supply 29V. The gate of the first field-effect transistor Q1 is connected to one end of the fifth capacitor C5, one end of the eighth resistor R8, one end of the ninth resistor R9, and the positive terminal of the second diode D2. The negative terminal of the second diode D2 is connected to the other end of the ninth resistor R9 and the seventh pin of the driver chip U2.

[0120] The drain of the second field-effect transistor Q2 is connected to the other end of the fifth capacitor C5, the other end of the eighth resistor R8, and the other end of the fourth capacitor C4. The gate of the second field-effect transistor Q2 is connected to the fifth pin of the driver chip U2. The tenth resistor R10 is connected between the drain and the source of the second field-effect transistor Q2.

[0121] A sixth capacitor C6 is connected between the first and fourth pins of the driver chip U2.

[0122] The source of the second field-effect transistor Q2 serves as the current sampling terminal of the left-turn drive circuit 300 and the right-turn drive circuit 400, and the drain of the second field-effect transistor Q2 serves as the motor connection terminal MI+, MI- of the left-turn drive circuit 300 and the right-turn drive circuit 400.

[0123] Specifically, in this embodiment, the MUC controls the forward and reverse rotation of the motor by outputting control signals to the motor through the motor control circuit. The current sampling circuit collects the real-time current of the motor periodically, and then compares the similarity of the current between adjacent periods to determine whether there is an obstruction. No other sensors are needed, which effectively controls the equipment cost.

[0124] The present invention also provides a lifting device, such as... Figure 9 As shown, the table 1 of the lifting equipment is equipped with a control box 2, which integrates the above-mentioned obstacle detection and retraction system.

[0125] The lifting leg 3 of the lifting equipment is equipped with a motor 4, and the motor control circuit is electrically connected to the positive and negative terminals of the motor 4.

[0126] The above are merely some embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present invention.

Claims

1. A method for reversing resistance in an electric motor, characterized in that, include: Step S1: Obtain the real-time current of the motor when it is in a stable operating state; Step S2: Calculate the similarity between the real-time current of the current cycle and the real-time current of the previous cycle, and determine whether the similarity is within a preset similarity threshold range. If so, return to step S2; If not, then determine that the motor is resisting and control the motor to reverse and retract.

2. The method for reversing resistance in an electric motor according to claim 1, characterized in that, Step S1 includes: Step S11: Determine whether the electronic control voltage received by the motor is within a preset voltage stability range, or whether the motor speed is within a preset speed stability range. If so, it is determined that the motor has entered a stable operating state, and then proceeds to step S12; If not, return to step S11; Step S12: Obtain the real-time current of the motor.

3. The method for reversing resistance in an electric motor according to claim 1, characterized in that, Step S2 includes: Step S21: Obtain the real-time current curve of the current cycle based on the real-time current processing of the current cycle, and obtain the real-time current curve of the previous cycle based on the real-time current processing of the previous cycle. Here, the cycle refers to one rotation of the motor. Step S22: Calculate the similarity between the real-time current curve of the current cycle and the real-time current curve of the previous cycle, and determine whether the similarity is within a preset similarity threshold range. If so, return to step S21; If not, then determine that the motor is resisting and control the motor to reverse and retract.

4. The method for reversing resistance in an electric motor according to claim 1, characterized in that, Step S2 includes: Step S21: Take multiple current values ​​from the real-time current of the previous cycle and add them to the cached current sequence according to a preset step size. Here, the cycle refers to one rotation of the motor. Step S22: Take multiple current values ​​from the real-time current of the current cycle according to the preset step size and add them to the real-time current sequence, where the cycle refers to one rotation of the motor. Step S23: Take the current values ​​with the same position from the cached current sequence and the real-time current sequence and calculate the corresponding ratio. Step S24: Take the average of all the ratios as the similarity and determine whether the similarity is within the preset similarity threshold range.

5. An electric motor resistance retraction system, characterized in that, include: MCU, the MCU being used to execute the circuit resistance back-off method as described in any one of claims 1-4; The motor control circuit has the control signal output terminal of the MCU connected to the control signal receiving terminal of the motor control circuit, and the control signal output terminal of the motor control circuit electrically connected to the positive and negative terminals of the motor. A current sampling circuit is provided, wherein the sampling terminal of the current sampling circuit is connected to the current sampling terminal of the motor control circuit, and the current data uploading terminal of the current sampling circuit is connected to the current data receiving terminal of the MCU.

6. The motor resistance retraction system according to claim 5, characterized in that, The current sampling circuit includes: A current sampling chip, wherein the third and fifth pins of the current sampling chip are connected to the current sampling terminal of the motor control circuit; The rising sampling circuit has its current output terminal connected to the first pin of the current sampling chip, its current input terminal connected to the second pin of the rising current sampling chip, and its current data upload terminal connected to the current data receiver of the MCU. A falling sampling circuit is provided, wherein the current output terminal of the falling sampling circuit is connected to the seventh pin of the current sampling chip, the current input terminal of the falling sampling circuit is connected to the sixth pin of the falling current sampling chip, and the current data upload terminal of the falling sampling circuit is connected to the current data receiver of the MCU.

7. The motor resistance retraction system according to claim 6, characterized in that, Both the rising sampling circuit and the falling sampling circuit include: A sampling resistor, one end of which is connected to the current data receiving terminal of the MCU, and the other end of which is connected to one end of a first resistor and one end of a first capacitor; The second resistor has one end connected to the other end of the first resistor and one end of the third resistor, and the other end of the third resistor and the other end of the first capacitor are grounded. One end of the second resistor serves as the current output terminal, and the other end of the second resistor serves as the current input terminal.

8. The motor resistance retraction system according to claim 5, characterized in that, The control signal output terminals of the MCU include a high-frequency left turn signal terminal, a low-frequency left turn signal terminal, a high-frequency right turn signal terminal, and a low-frequency right turn signal terminal; The motor control circuit includes: A left-turn drive circuit, wherein the high-frequency signal receiving end of the left-turn drive circuit is connected to the left-turn high-frequency signal end, the low-frequency signal receiving end of the left-turn drive circuit is connected to the left-turn low-frequency signal end, and the motor connection end of the left-turn drive circuit is connected to the positive terminal of the motor. A right-turn drive circuit, wherein the high-frequency signal receiving end of the right-turn drive circuit is connected to the right-turn high-frequency signal end, the low-frequency signal receiving end of the right-turn drive circuit is connected to the right-turn low-frequency signal end, and the motor connection end of the right-turn drive circuit is connected to the negative terminal of the motor. The current sampling terminal of the left turn drive circuit and the current sampling terminal of the right turn drive current are connected to one end of the fourth resistor and the fifth resistor. The other end of the fifth resistor is grounded. The other end of the fourth resistor is connected to one end of the sixth resistor, one end of the second capacitor, one end of the third capacitor, and the sampling terminal of the current sampling circuit. The other ends of the sixth resistor, the second capacitor, and the third capacitor are grounded.

9. The motor resistance retraction system according to claim 8, characterized in that, Both the left-turn drive circuit and the right-turn drive circuit include: The driver chip has a second pin serving as the high-frequency signal receiver and a third pin serving as the low-frequency signal receiver. The seventh resistor has one end connected to the first pin of the driver chip, and the other end connected to the positive terminal of the first diode. The negative terminal of the first diode is connected to the eighth pin of the driver chip and one end of the fourth capacitor. The other end of the fourth capacitor is connected to the sixth pin of the driver chip. The first field-effect transistor has its drain connected to the power supply, and its gate connected to one end of the fifth capacitor, one end of the eighth resistor, one end of the ninth resistor, and the positive terminal of the second diode. The negative terminal of the second diode is connected to the other end of the ninth resistor and the seventh pin of the driver chip. The second field-effect transistor has its drain connected to the other end of the fifth capacitor, the other end of the eighth resistor, and the other end of the fourth capacitor. Its gate is connected to the fifth pin of the driver chip. A tenth resistor is connected between the drain and source of the second field-effect transistor. A sixth capacitor is connected between the first and fourth pins of the driver chip. The source of the second field-effect transistor serves as the current sampling terminal of the left-turn drive circuit and the right-turn drive circuit, and the drain of the second field-effect transistor serves as the motor connection terminal of the left-turn drive circuit and the right-turn drive circuit.

10. A lifting device, characterized in that, The lifting device is equipped with a control box, which integrates an electric motor resistance retraction system as described in any one of claims 5-9; The lifting legs of the lifting device are equipped with motors, and the motor control circuit in the motor resistance retraction system is electrically connected to the positive and negative terminals of the motor.

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