Servo drive braking circuit and servo driver control method

Abstract

The invention provides a servo drive braking circuit and a servo driver control method, and relates to the technical field of servo driver control. Comprising a main loop and a driving circuit, the driving circuit is connected with the main loop and is used for driving a servo driver connected with the main loop to brake, the servo driver further comprises a main control chip and a detection circuit, and the main loop comprises a power MOS tube, a fly-wheel diode, a state detection resistor and an external brake resistor; the servo drive braking circuit solves the problem that in the prior art, fault judgment logic and hardware circuits are complex, judgment logic simplification is achieved, main faults of the braking circuit can be rapidly diagnosed, diagnosis logic is clear, a user can rapidly position the faults conveniently, hardware of the detection circuit is simple in design, and the detection cost is low. The implementation cost can be effectively reduced, and wide application is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of servo drive control, and in particular, to a servo drive braking circuit and a servo drive control method. Background Art

[0002] During the operation of a servo motor, when encountering load changes, performing braking or deceleration operations, due to the inertia of the motor, energy will be fed back to the servo controller, thereby causing an increase in the drive bus voltage. If the bus voltage is too high, it may cause the components inside the controller to be damaged due to overvoltage, ultimately leading to controller failures and affecting the stable operation of the entire system. To effectively address this problem, a braking circuit is specifically provided in the servo drive controller to absorb this fed-back energy, ensure that the system bus voltage remains within a safe range, and make the operation of the motor more stable and reliable. Therefore, in the design of servo drives, the configuration of the braking circuit is particularly important, and it needs to flexibly adapt to load changes and braking requirements in various application scenarios to ensure the best performance of the system.

[0003] The prior art proposes to achieve fault diagnosis of the braking circuit by adding a dedicated fault diagnosis chip and corresponding control and feedback circuits, thereby solving the problem of being unable to accurately judge possible faults in the braking circuit itself. However, the prior art solves this problem based on a multi-signal combination judgment method, with a complex fault judgment logic and a relatively complex required hardware circuit, resulting in a relatively high cost, which to a certain extent limits its wide application. Summary of the Invention

[0004] The purpose of the present invention is to provide a servo drive braking circuit and a servo drive control method, which solve the problems of complex fault judgment logic and hardware circuit in the prior art, simplify the judgment logic, can quickly diagnose the main faults of the braking circuit, have a clear diagnosis logic for easy user fault location, and have a simple hardware design for the detection circuit, which can effectively reduce the implementation cost and is conducive to wide application.

[0005] In a first aspect, the present invention provides a servo drive braking circuit, including a main circuit and a drive circuit. The drive circuit is connected to the main circuit and is used to drive a servo drive connected to the main circuit to perform braking. It also includes a main control chip and a detection circuit. The main circuit includes a power MOS transistor, a freewheeling diode, a state detection resistor, and an external braking resistor; Wherein, the gate of the power MOS transistor is connected to the drive circuit; the source of the power MOS transistor is connected to one end of the state detection resistor, and the other end of the state detection resistor is connected to the servo driver; the source of the power MOS transistor is also connected to the detection circuit, the drain of the power MOS transistor is simultaneously connected to the positive electrode of the freewheeling diode and one end of the external braking resistor, and the other end of the external braking resistor is simultaneously connected to the negative electrode of the freewheeling diode and the servo driver; the detection circuit can communicate with the drive circuit through the main control chip.

[0006] The servo drive braking circuit provided by the present invention realizes the fault judgment of the braking circuit with a simpler circuit design and judgment logic, avoids the further damage of the relevant circuits caused by turning on the braking circuit when the braking circuit has a fault, and can timely detect and locate the fault after the braking circuit operates.

[0007] Further, the resistance of the state detection resistor satisfies the following conditions: ; Wherein, is the resistance of the state detection resistor, is the bus voltage of the servo driver, is the loop current when the main circuit works normally, is the resistance of the external braking resistor, and the is the on-resistance of the power MOS transistor.

[0008] Further, the drive circuit includes a drive chip, a first resistor, a second resistor and a first diode; Wherein, the drive chip is used to receive the detection signal sent by the main control chip, the drive chip is simultaneously connected to the first end of the first resistor and the first end of the second resistor, the second end of the second resistor is connected to the negative electrode of the first diode, and the positive electrode of the first diode is connected to the second end of the first resistor and is used to output a drive signal.

[0009] Further, the detection circuit includes a third resistor, an optocoupler chip and a fourth resistor; Wherein, the first end of the third resistor is used to receive the electrical signal sent by the state detection resistor, the second end of the third resistor is connected to the positive electrode of the diode side of the optocoupler chip, and the negative electrode of the diode side of the optocoupler chip is grounded; the collector of the transistor side of the optocoupler chip is connected to the first end of the fourth resistor, the second end of the fourth resistor is used to output the supply voltage, and the collector of the transistor side of the optocoupler chip is also used to output a feedback signal to the main control chip; the emitter of the transistor side of the optocoupler chip is grounded.

[0010] Further, the conduction current on the diode side of the optocoupler chip satisfies the following conditions: ; ; ; Wherein, is the conduction current on the diode side of the optocoupler chip, is the voltage across the state detection resistor, is the preset conduction voltage, is the resistance of the third resistor, is the resistance of the state detection resistor, is the preset desired resistor power.

[0011] In a second aspect, the present invention provides a servo driver control method based on the above-mentioned servo drive braking circuit, including the following steps: S1. Periodically sample the bus voltage of the servo driver; S2. Compare the bus voltage of the servo driver with a preset braking function activation threshold. If the bus voltage of the servo driver is greater than or equal to the braking function activation threshold, control the main control chip to send a first detection signal to make the detection circuit output a first feedback signal, and judge the state of the servo drive braking circuit according to the first feedback signal, and perform corresponding actions; the first detection signal is a pulse signal in which a low-level pulse signal and a high-level pulse signal alternate according to a unit pulse time; S3. Compare the bus voltage of the servo driver with a preset braking function deactivation threshold. If the bus voltage of the servo driver is less than the braking function deactivation threshold, control the main control chip to send a second detection signal to make the detection circuit output a second feedback signal, and judge the state of the servo drive braking circuit according to the second feedback signal, and perform corresponding actions; the second detection signal is a pulse signal in which a low-level pulse signal and a high-level pulse signal alternate according to a unit pulse time.

[0012] This diagnostic method based on pulse pattern analysis can determine whether a fault has occurred and the specific fault type with a single-channel signal. Compared with the prior art, it simplifies the complexity of the judgment logic.

[0013] Further, in step S2, the steps of judging the state of the servo drive braking circuit according to the first feedback signal and performing corresponding actions include: S21. If the continuous three pulse times of the first feedback signal are all high-level pulse signals, it is determined that the servo drive braking circuit is in the first abnormal state, a fault warning is issued and the first fault type is reported; S22. If the continuous three pulse times of the first feedback signal are all low-level pulse signals, it is determined that the servo drive braking circuit is in the second abnormal state, a fault warning is issued and the second fault type is reported; S23. If the continuous three pulse times of the first feedback signal are pulse signals with alternating low-level and high-level pulse signals, it is determined that the servo drive braking circuit is in the normal state, and the braking function is enabled.

[0014] Further, in step S3, the steps of judging the state of the servo drive braking circuit according to the second feedback signal and performing corresponding actions include: S31. If the continuous three pulse times of the second feedback signal are all high-level pulse signals, it is determined that the servo drive braking circuit is in the third abnormal state, a fault warning is issued and the third fault type is reported; S32. If the continuous three pulse times of the second feedback signal are all low-level pulse signals, it is determined that the servo drive braking circuit is in the fourth abnormal state, a fault warning is issued and the fourth fault type is reported; S33. If the continuous three pulse times of the second feedback signal are pulse signals with alternating low-level and high-level pulse signals, it is determined that the servo drive braking circuit is in the normal state, and step S1 is returned to for execution.

[0015] Further, both the first fault type and the third fault type are that the external braking resistor or the power MOS transistor in the servo drive braking circuit is open.

[0016] Further, both the second fault type and the fourth fault type are that the power MOS transistor in the servo drive braking circuit is short-circuited.

[0017] As can be seen from the above, the servo drive braking circuit provided by the present invention simplifies the hardware design of its detection circuit compared with the prior art, can effectively reduce the implementation cost, is conducive to wide application, and no longer needs to use the method of combining multiple signals to judge the faults of the braking circuit. Its corresponding judgment logic is correspondingly simplified, and the main faults of the braking circuit can be quickly diagnosed. The diagnosis logic is clear and convenient for users to quickly locate faults.

[0018] Other features and advantages of the present invention will be described in the subsequent specification, and in part, will be obvious from the specification, or can be understood by implementing the embodiments of the present invention. The objectives and other advantages of the present invention can be achieved and obtained by the structures particularly pointed out in the written specification and the accompanying drawings. Description of the Drawings

[0019] Figure 1 FIG. is a schematic structural diagram of a servo drive braking circuit provided for an embodiment of the present invention.

[0020] Figure 2 FIG. is a schematic structural diagram of a drive circuit in an embodiment of the present invention.

[0021] Figure 3 FIG. is a schematic structural diagram of a detection circuit in an embodiment of the present invention.

[0022] Figure 4 FIG. is a flowchart of a servo drive control method provided for an embodiment of the present invention.

[0023] Figure 5 FIG. is a waveform signal diagram of detection signals and feedback signals in different states of a servo drive braking circuit in an embodiment of the present invention.

[0024] Reference Numeral Description: 100, main circuit; 200, drive circuit; 210, drive chip; 300, main control chip; 400, detection circuit; Q, power MOS transistor; Dx, freewheeling diode; Ra, state detection resistor; Rb, external braking resistor; R1, first resistor; R2, second resistor; D1, first diode; Qg, detection signal; Qgb, drive signal; R3, third resistor; OP, optocoupler chip; R4, fourth resistor; Vcc, supply voltage; Bfb, feedback signal; M, servo motor. Detailed Embodiments

[0025] The following details the embodiments of the present invention. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

[0026] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0027] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0029] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but only represents the selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0032] Referring to the attached Figure 1 , the present invention provides a servo drive braking circuit, including a main circuit 100 and a drive circuit 200. The drive circuit 200 is connected to the main circuit 100 and is used to drive a servo driver connected to the main circuit 100 to perform braking. It further includes a main control chip 300 and a detection circuit 400. The main circuit includes a power MOS transistor Q, a freewheeling diode Dx, a state detection resistor Ra, and an external braking resistor Rb; Among them, the gate of the power MOS transistor Q is connected to the drive circuit 200; the source of the power MOS transistor Q is connected to one end of the state detection resistor Ra, and the other end of the state detection resistor Ra is connected to the servo driver; the source of the power MOS transistor Q is also connected to the detection circuit 400. The drain of the power MOS transistor Q is simultaneously connected to the positive electrode of the freewheeling diode Dx and one end of the external braking resistor Rb, and the other end of the external braking resistor Rb is simultaneously connected to the negative electrode of the freewheeling diode Dx and the servo driver; the detection circuit 400 can communicate with the drive circuit 200 through the main control chip 300.

[0033] Among them, the state detection resistor refers to a resistor component used to sense the state of a circuit, which can be implemented in ways such as a sampling resistor, a shunt, etc. Its main purpose is to generate a detectable voltage signal when the braking current flows through. The detection circuit refers to a circuit used to process the signal generated by the state detection resistor and transmit the state information to the main control chip, which can be implemented in ways such as an operational amplifier circuit, a comparator circuit, an analog-to-digital converter interface circuit, or an optocoupler isolation circuit, etc. Its main purpose is to convert the analog signal into a digital signal or an isolated signal for the main control chip to process. The main control chip refers to a processor device used to receive the state information of the detection circuit, perform logical judgments, and control the drive circuit, which can be implemented in ways such as a microcontroller, a digital signal processor, or a field-programmable gate array, etc. Its main purpose is to achieve intelligent control, state monitoring, and fault diagnosis of the braking function. The drive circuit refers to a circuit used to receive the electrical signal of the main control chip and generate a signal to drive the power MOS transistor to conduct or cut off, which can be implemented in ways such as a dedicated MOSFET driver chip, a discrete component drive circuit, etc. Its main purpose is to provide sufficient voltage and current to quickly and effectively control the switching state of the power MOS transistor.

[0034] The core innovation of this application lies in that by introducing a state detection resistor into the main circuit and combining it with the detection circuit and the main control chip, the direct or indirect detection of the working state of the braking circuit is realized, thus simplifying the complex fault judgment logic and hardware circuit in the prior art, reducing the cost, and improving the efficiency and accuracy of fault diagnosis.

[0035] Specifically, the servo drive braking circuit absorbs the energy fed back by the servo driver through the main circuit and controls the switching state of the main circuit through the drive circuit. During specific operation, when the bus voltage of the servo driver reaches the preset threshold, the main control chip, based on the bus voltage state and internal logic, controls the drive circuit to generate a drive signal through communication with the drive circuit, causing the power MOS transistor in the main circuit to conduct. At this time, the fed-back energy is converted into heat energy and consumed through the power MOS transistor, the state detection resistor, and the external braking resistor. The current flowing through the power MOS transistor also flows through the state detection resistor, generating a voltage signal across the state detection resistor. This voltage signal is sent to the detection circuit for processing. The detection circuit feeds back the processed state information (for example, information reflecting the presence or magnitude of the current) to the main control chip. After receiving the state information fed back by the detection circuit, the main control chip combines the detection signal Qg sent to the drive circuit to analyze and judge the current working state of the braking circuit (for example, whether it is conducting normally, open-circuited, or short-circuited). According to the judgment result, the main control chip can continue to maintain braking, turn off braking, adjust the drive signal, or issue a fault warning. The freewheeling diode provides a current path when the power MOS transistor is turned off, protecting the power MOS transistor. Through the state detection resistor and the detection circuit, the main control chip can obtain the operation information of the braking circuit in real time, thereby realizing effective monitoring and fault diagnosis of the braking circuit state.

[0036] As a preferred embodiment, the solution of the present application is specifically implemented as follows: The main control chip can adopt a microcontroller of the STM32 series. The drive circuit can adopt a dedicated MOSFET drive chip, such as IR2110. The state detection resistor can be selected as a low-resistance power resistor, such as a 0.1-ohm / 5-watt resistor. The detection circuit can adopt an optocoupler chip, such as PC817. The diode side of it is connected to one end of the state detection resistor through a current-limiting resistor, and the collector of the triode side is connected to a GPIO pin of the main control chip, and the emitter is grounded. The power MOS transistor can be selected as an N-channel power MOSFET with appropriate voltage withstand and current ratings, such as IRF460. The external braking resistor can be selected as a high-power wire-wound resistor, and its resistance value is calculated and determined according to system requirements. The freewheeling diode can be selected as a fast-recovery diode, such as FR307. The state detection resistor is connected in series between the source of the power MOS transistor and the servo driver bus. The drain of the power MOS transistor is connected to one end of the external braking resistor and the positive pole of the freewheeling diode. The other end of the external braking resistor is connected to the negative pole of the freewheeling diode and the servo driver bus. The optocoupler diode of the detection circuit is connected across the state detection resistor (through the current-limiting resistor), and the output of the optocoupler triode is connected to the input pin of the main control chip. The PWM output pin of the main control chip is connected to the input end of the drive chip, and the output end of the drive chip is connected to the gate of the power MOS transistor.

[0037] Through the above solution, the present application can effectively solve the problems of complex braking circuit fault judgment logic, complex hardware circuit, and high cost in the prior art. By introducing a state detection resistor and cooperating with a detection circuit and a main control chip, real-time and simplified detection of the working state of the braking circuit is achieved, making the fault judgment logic more direct, simplifying the required hardware circuit, and thus reducing the overall cost. At the same time, the ability to detect changes in the braking circuit state is beneficial to promptly detecting abnormal situations, ensuring that the braking circuit can work reliably under normal conditions, effectively absorbing feedback energy, and protecting the servo driver.

[0038] In some embodiments, the resistance of the state detection resistor satisfies the following conditions: ; wherein, is the resistance of the state detection resistor Ra, is the bus voltage of the servo driver, is the loop current when the main loop 100 is working normally, is the resistance of the external braking resistor Rb, is the on-resistance of the power MOS transistor Q.

[0039] In some embodiments, referring to the attached Figure 2 , the drive circuit 200 includes a drive chip 210, a first resistor R1, a second resistor R2, and a first diode D1; wherein, the drive chip 210 is used to receive the detection signal Qg sent by the main control chip 300. The drive chip 210 is simultaneously connected to the first end of the first resistor R1 and the first end of the second resistor R2. The second end of the second resistor R2 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the second end of the first resistor R1 and is used to output the drive signal Qgb.

[0040] Among them, the drive chip refers to an integrated circuit specifically designed to drive power switching devices (such as power MOS transistors, IGBTs, etc.), which can be implemented using a dedicated gate drive chip. The first resistor R1 and the second resistor R2 refer to standard resistor elements used to limit current or adjust voltage, which can be implemented using surface mount resistors or through-hole resistors. The first diode D1 refers to a semiconductor device with a unidirectional conduction characteristic, which can be implemented using a common rectifier diode or a fast recovery diode. The detection signal Qg refers to an electrical signal sent by the main control chip and used to control the operation of the drive circuit, which can be implemented using a pulse width modulation (PWM) signal or a digital logic signal. The drive signal Qgb refers to an electrical signal output by the drive circuit and directly applied to the gate of the power MOS transistor, and its waveform and level are suitable for driving the power MOS transistor to perform switching operations.

[0041] Specifically, the drive circuit receives the detection signal Qg from the main control chip through a drive chip. The output terminal of the drive chip is connected to one end of a first resistor R1 and a second resistor R2. The other end of the first resistor R1 is connected to the positive electrode of a first diode D1. The other end of the second resistor R2 is connected to the negative electrode of the first diode D1. The drive signal Qgb is output from the connection point between the other end of the first resistor R1 and the positive electrode of the first diode D1, and this output signal is applied to the gate of the power MOS transistor. This connection method constitutes an asymmetric drive path. When the drive chip outputs a high level (or an enabling signal), current mainly charges the gate of the power MOS transistor through the first resistor R1 to turn it on. When the drive chip outputs a low level (or a disabling signal), the charge on the gate of the power MOS transistor discharges through the path composed of the second resistor R2 and the first diode D1 to turn it off. By selecting the first resistor R1 and the second resistor R2 with different resistance values, the turn-on and turn-off speeds of the power MOS transistor can be independently controlled. For example, reducing the first resistor R1 can increase the turn-on speed, and reducing the second resistor R2 can increase the turn-off speed. The first diode D1 ensures that current does not pass through the second resistor R2 during turn-on, and current passes through the path of the second resistor R2 and the first diode D1 during turn-off. This asymmetric drive helps to optimize the switching waveform, reduce switching losses, and prevent mis-conduction of the power MOS transistor during rapid voltage changes. The drive circuit converts the control instruction of the main control chip into the voltage and current signals required to reliably drive the power MOS transistor, ensuring that the power MOS transistor switches accurately according to the instruction. The reliable switching of the power MOS transistor is the key to the normal operation of the braking circuit, which directly affects the absorption of braking energy and the accuracy of state judgment through the state detection resistor. Therefore, the reliability of the drive circuit directly supports the functional implementation of the entire braking circuit and the effectiveness of the state detection mechanism.

[0042] Through the above solution, the present application provides a specific drive circuit structure that can effectively receive the electrical signal of the main control chip and generate a reliable drive signal suitable for driving the power MOS transistor. Through the design of an asymmetric turn-on and turn-off path, the switching characteristics of the power MOS transistor are optimized, the switching losses are reduced, and the drive efficiency and reliability are improved. Thereby, the accurate switching of the power MOS transistor is ensured, enabling the braking circuit to operate normally according to the instruction of the main control chip, effectively absorbing the feedback energy, maintaining the stability of the bus voltage, and providing a basis for accurately detecting the state of the braking circuit through the state detection resistor.

[0043] In some embodiments, referring to Figure 3 , the detection circuit 400 includes a third resistor R3, an optocoupler chip OP, and a fourth resistor R4; Among them, the first end of the third resistor R3 is used to receive the electrical signal sent by the status detection resistor Ra. The second end of the third resistor R3 is connected to the positive pole of the diode side of the optocoupler chip OP. The negative pole of the diode side of the optocoupler chip OP is grounded. The collector of the triode side of the optocoupler chip OP is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is used to output the supply voltage Vcc. The collector of the triode side of the optocoupler chip OP is also used to output the feedback signal Bfb to the main control chip 300. The emitter of the triode side of the optocoupler chip OP is grounded.

[0044] Among them, the optocoupler chip refers to an electronic component that uses light as a medium to transmit electrical signals, thereby achieving electrical isolation between the input circuit and the output circuit. It usually includes a light-emitting element (such as a light-emitting diode) and a photosensitive element (such as a phototransistor or a photodarlington transistor). This isolation characteristic can effectively block the influence of high voltage or noise on the low-voltage circuit on the output side from the input side. The optocoupler chip can be implemented in various types, such as optocouplers with phototransistor output, photodarlington transistor output, or logic gate output.

[0045] Specifically, the detection circuit aims to safely and reliably transmit the status signal on the status detection resistor in the main circuit to the main control chip by constructing a path containing an optocoupler chip. The first end of the third resistor is connected to the status detection resistor to receive the electrical signal reflecting the status of the braking circuit. The second end of the third resistor is connected to the positive pole of the diode side of the optocoupler chip. The negative pole of the diode side of the optocoupler chip is grounded, forming the input loop of the optocoupler chip. The third resistor limits the current flowing through the optocoupler diode. The core of the optocoupler chip lies in the optical isolation characteristic between its input side (diode) and output side (triode). When the current on the input side reaches a certain value, the diode emits light, and the optical signal triggers the triode on the output side to conduct. This isolation mechanism effectively isolates the status signal on the high-voltage side of the main circuit from the main control chip, improving the safety and anti-interference ability of the system. The collector of the triode side of the optocoupler chip is connected to the first end of the fourth resistor, and the second end of the fourth resistor is connected to the supply voltage, forming the output loop of the optocoupler chip. The fourth resistor acts as a pull-up resistor to pull up the collector voltage to the supply voltage when the optocoupler triode is cut off. When the optocoupler triode conducts, the collector voltage drops. The optocoupler chip converts the optical signal received on the input side into an electrical signal (voltage change) on the output side, that is, the feedback signal. This feedback signal is output from the collector of the triode side of the optocoupler chip and is sent to the main control chip. Thus, according to the level change of the feedback signal received by the main control chip, the original electrical signal status on the status detection resistor can be judged, and then the current working status of the braking circuit can be identified. This method uses the isolation and conversion functions of the optocoupler chip to solve the problem of safely and reliably transmitting the high-voltage status signal to the main control chip, providing a basis for subsequent status judgment and fault diagnosis.

[0046] Through the above solution, the detection circuit provides a safe and reliable signal transmission path, effectively transmitting the status detection signal on the high-voltage side of the main circuit to the main control chip. It eliminates the safety hazards brought by high voltage through optical isolation, reduces signal interference, and solves the problem of level mismatch. This enables the control circuit to accurately obtain the status information of the braking circuit, thereby realizing effective status monitoring and fault diagnosis.

[0047] In some embodiments, the conduction current on the diode side of the optocoupler chip OP satisfies the following conditions: ; Where, is the conduction current on the diode side of the optocoupler chip OP, is the voltage across both ends of the status detection resistor Ra, is the preset conduction voltage, is the resistance of the third resistor R3.

[0048] It should be noted that, , , so , because the status detection resistor Ra is within the system. When selecting the status detection resistor Ra, on the one hand, it is necessary to consider that the voltage across both ends of the status detection resistor Ra has the driving ability for the optocoupler chip in the subsequent detection circuit, and on the other hand, it is necessary to consider the power of the status detection resistor Ra. The volume of the status detection resistor Ra cannot be too large, so the power is generally set to be less than or equal to the expected resistor power (for example ). Therefore, in practical applications, the voltage across both ends of the status detection resistor Ra satisfies the following two conditions: ; .

[0049] Where, is the resistance of the status detection resistor Ra, is the preset expected resistor power.

[0050] Referring to Appendix Figure 4 , the present invention provides a servo driver control method based on the servo drive braking circuit in the above embodiments, including the following steps: S1. Periodically sample the bus voltage of the servo driver; S2. Compare the bus voltage of the servo driver with a preset braking function activation threshold. When the bus voltage of the servo driver is greater than or equal to the braking function activation threshold, control the main control chip to send a first detection signal to make the detection circuit output a first feedback signal, and judge the state of the servo drive braking circuit according to the first feedback signal, and perform corresponding actions; the first detection signal is a pulse signal in which a low-level pulse signal and a high-level pulse signal alternate according to the unit pulse time. S3. Compare the bus voltage of the servo driver with a preset braking function deactivation threshold. When the bus voltage of the servo driver is less than the braking function deactivation threshold, control the main control chip to send a second detection signal to make the detection circuit output a second feedback signal, and judge the state of the servo drive braking circuit according to the second feedback signal, and perform corresponding actions; the second detection signal is a pulse signal in which a low-level pulse signal and a high-level pulse signal alternate according to the unit pulse time.

[0051] Among them, the main control chip refers to a central processing unit used to execute control logic, generate electrical signals, and process feedback information, which can be implemented by a microcontroller, a digital signal processor, or an application-specific integrated circuit. The detection circuit refers to a circuit used to receive the electrical signals generated by the state detection resistor in the braking circuit and convert them into feedback signals that can be read by the main control chip, which can be implemented by a circuit structure including components such as resistors and optocoupler chips. The first detection signal and the second detection signal (both the first detection signal and the second detection signal belong to the detection signal Qg) refer to a specific pulse sequence generated by the main control chip for actively detecting the response characteristics of the braking circuit when attempting to drive. The specific pulse pattern of this signal is the basis for state diagnosis. The first feedback signal and the second feedback signal (both the first feedback signal and the second feedback signal belong to the feedback signal Bfb) refer to the electrical signals output by the detection circuit according to the response of the braking circuit to the detection signal. The pattern of this signal reflects the current working state of the braking circuit. Judging the state of the servo drive braking circuit according to the first feedback signal and judging the state of the servo drive braking circuit according to the second feedback signal means determining whether the braking circuit is in a normal working state or a certain abnormal state (such as open circuit or short circuit) by analyzing the pulse pattern of the received feedback signal (for example, whether it is consistent with the pattern of the sent detection signal, or whether it shows a continuous high level or low level). Performing corresponding actions means taking corresponding control measures (such as allowing or prohibiting the activation / deactivation of the braking function) or fault handling measures (such as sending a warning signal) according to the judged state of the braking circuit.

[0052] Specifically, the method first periodically samples the bus voltage of the servo driver, which is the basis for braking control because the level of the bus voltage directly reflects the degree of energy feedback from the servo motor M in the servo driver and whether the braking function needs to be started or turned off. Then, the sampled bus voltage is compared with a preset braking function activation threshold. When the bus voltage reaches or exceeds the activation threshold, it indicates that the bus voltage of the servo driver is too high and the braking function needs to be started to consume the feedback energy. At this time, the control main control chip sends a specific first detection signal, which consists of low-level pulses and high-level pulses alternating according to the unit pulse time. This pulse signal acts on the power MOS tube in the braking circuit through the drive circuit, causing it to attempt to perform switching actions according to the pulse pattern. At the same time, the state detection resistor in the braking circuit generates an electrical signal reflecting the current state of the circuit, which is received and processed by the detection circuit and outputs a first feedback signal. This way of sending a specific pulse signal and observing the circuit response (feedback signal) can detect the working state of the braking circuit. Then, according to the pulse pattern of the received first feedback signal, the current state of the servo drive braking circuit is judged. If the pulse pattern of the feedback signal is the same as the pattern of the sent detection signal (i.e., it is also an alternating pulse), it is judged that the circuit is in a normal state and the braking function can be safely activated. If the feedback signal pattern is abnormal (for example, continuously high level or continuously low level), it is judged that the circuit is in an abnormal state (such as an open circuit fault), and a fault warning is issued to report the corresponding fault type, thus avoiding forced operation when the circuit is abnormal. Similarly, the sampled bus voltage is compared with a preset braking function deactivation threshold. When the bus voltage is lower than the deactivation threshold, it indicates that the bus voltage has dropped to a safe range and the braking function is no longer needed. At this time, the control main control chip sends a second detection signal, which is also a pulse signal composed of low-level pulses and high-level pulses alternating according to the unit pulse time. The detection circuit outputs a second feedback signal. According to the pulse pattern of the received second feedback signal, the current state of the servo drive braking circuit is judged. If the feedback signal pattern is normal (alternating), it is judged that the circuit is in a normal state and the braking function can be safely deactivated and the process returns to continue periodically sampling the bus voltage. If the feedback signal pattern is abnormal (for example, continuously high level or continuously low level), it is judged that the circuit is in an abnormal state (such as a short circuit fault), and a fault warning is issued to report the corresponding fault type. This method utilizes the state detection resistor added in the braking circuit and the state information provided by the detection circuit, generates a specific pulse signal through the main control chip to actively detect the circuit state, and makes a judgment according to the feedback signal pattern output by the detection circuit. This diagnostic method based on pulse pattern analysis enables the main control chip to effectively utilize the hardware foundation for intelligent control and fault diagnosis, and transforms the state detection ability of the hardware into executable control and processing logic.By performing state detection based on the analysis of specific pulse signals and feedback signal patterns before both enabling and disabling the braking function, this method can effectively determine the normal operating state of the braking circuit as well as various abnormal states such as open circuits and short circuits, and take corresponding control or fault handling measures according to the judgment results.

[0053] As a preferred embodiment, the solution of this application is specifically implemented as follows: The main control chip can use a microcontroller of the STM32 series. The periodic sampling of the bus voltage can be achieved through the ADC module of the microcontroller. The preset braking function enabling threshold and disabling threshold are stored in the program memory of the microcontroller. When the bus voltage exceeds the enabling threshold, the microcontroller generates a first detection signal through its GPIO pin or timer module. This signal is a pulse train in which the low level and high level alternate according to the preset unit pulse time (for example, 10 microseconds), and is sent to the drive circuit. The detection circuit can adopt a structure including an optocoupler chip (for example, PC817) and a resistor. The voltage change on the state detection resistor drives the LED of the optocoupler, and the transistor side of the optocoupler outputs a feedback signal. The microcontroller reads the first feedback signal output by the detection circuit through another GPIO pin. The firmware program of the microcontroller analyzes the pulse pattern of the received first feedback signal. For example, the program can check the signal levels within three consecutive pulse times. If the feedback signal also shows an alternating pattern of high level, low level, and high level within these three pulse times, it is determined that the braking circuit is normal, and the microcontroller then outputs a continuous drive signal to enable the braking function. If the feedback signal is continuously high level or continuously low level within these three pulse times, it is determined that the circuit is abnormal (for example, open circuit or short circuit), and the microcontroller does not enable the braking function. Instead, it sends a fault warning message through a communication interface (such as CAN, RS485) and may also light up a fault indicator. Similarly, when the bus voltage is lower than the disabling threshold, the microcontroller generates a second detection signal, sends it to the drive circuit, and reads the second feedback signal output by the detection circuit. The circuit state is judged according to the pulse pattern of the second feedback signal. If the feedback signal alternates normally, it is determined that the circuit is normal, and the microcontroller stops outputting the drive signal to disable the braking function and continues to sample the bus voltage. If the feedback signal is abnormal, it is determined that the circuit is abnormal and a fault warning message is sent.

[0054] Through the above solution, this application can accurately judge the state of the braking circuit (including normal operation and various abnormal states), and perform corresponding control or fault handling according to the state, thereby improving the reliability and safety of the servo drive system. And this diagnostic method based on pulse pattern analysis can judge whether a fault occurs and the specific fault type with a single-channel signal. Compared with the prior art, it simplifies the complexity of the judgment logic.

[0055] In some embodiments, refer to the appendix Figure 5, in step S2, the steps of judging the state of the servo drive braking circuit according to the first feedback signal and performing corresponding actions include: S21. If the pulse times of three consecutive pulses of the first feedback signal are all high-level pulse signals, it is determined that the servo drive braking circuit is in the first abnormal state, a fault warning is issued and the first fault type is reported; S22. If the pulse times of three consecutive pulses of the first feedback signal are all low-level pulse signals, it is determined that the servo drive braking circuit is in the second abnormal state, a fault warning is issued and the second fault type is reported; S23. If the pulse times of three consecutive pulses of the first feedback signal are pulse signals with alternating low-level and high-level pulse signals, it is determined that the servo drive braking circuit is in the normal state, and the braking function is enabled.

[0056] Furthermore, the first fault type is an open circuit of the external braking resistor or the power MOS transistor in the servo drive braking circuit.

[0057] Furthermore, the second fault type is a short circuit of the power MOS transistor in the servo drive braking circuit.

[0058] Among them, the three pulse times refer to three consecutive specific time periods for observing or sampling the first feedback signal, and each time period corresponds to a unit pulse time of the first detection signal. The high-level pulse signal means that within a specific pulse time, the voltage of the signal is within a preset high-level range. The low-level pulse signal means that within a specific pulse time, the voltage of the signal is within a preset low-level range. The alternating pulse signal means that within three consecutive pulse times, the level of the signal switches between high and low levels in a certain order (such as low-high-low or high-low-high). The first abnormal state and the second abnormal state refer to the abnormal working states of the servo drive braking circuit diagnosed according to the specific pulse pattern of the first feedback signal, and they represent different types of circuit faults or abnormal conditions. The normal state refers to the expected working state of the servo drive braking circuit diagnosed according to the specific pulse pattern of the first feedback signal, indicating that the circuit can correctly respond to the detection signal. Issuing a fault warning means that the system prompts the existence of an abnormal situation to the outside through a certain method (such as an indicator light, a display screen, a communication interface). Reporting the first fault type and reporting the second fault type mean that the system further provides specific information about the detected abnormality to facilitate fault location and elimination. Enabling the braking function means that the system activates the servo drive braking circuit to start absorbing the feedback energy.

[0059] Specifically, when the bus voltage of the servo driver rises and reaches the braking function activation threshold, the main control chip will initiate a diagnostic process. The main control chip sends a first detection signal with a preset and specific alternating pattern (such as low-high-low) to the drive circuit. This detection signal acts on the key components (such as power MOS transistors) of the braking circuit through the drive circuit, and the detection circuit monitors the state changes of the braking circuit to generate a first feedback signal. The core of this solution lies in analyzing the level pattern of this first feedback signal within three consecutive pulse times. If the first feedback signal always remains high during these three pulse times, the system determines that the braking circuit is in a first abnormal state and triggers corresponding fault warnings and a first fault type report. If the first feedback signal always remains low during these three pulse times, the system determines that the braking circuit is in a second abnormal state and triggers fault warnings and a second fault type report. Only when the first feedback signal shows an expected alternating pattern of low and high levels corresponding to the first detection signal (such as high-low-high) during these three pulse times, the system determines that the braking circuit is in a normal state and then proceeds to perform the operation of activating the braking function. This judgment mechanism based on the pulse pattern of the feedback signal utilizes the different response characteristics of the braking circuit to a specific detection signal in different states, providing a simple and effective diagnostic method. By combining with the structure of the servo drive braking circuit (including the state detection resistor and the detection circuit) and the specific detection signal sent by the main control chip, this solution can accurately distinguish the normal and abnormal states of the braking circuit and take targeted measures, thereby improving the reliability of the braking function.

[0060] Specifically, regarding the detailed cause analysis of the first abnormal state: When the external braking resistor Rb is open (i.e., the external braking resistor Rb is not connected), when the detection signal Qg sent by the main control chip is at a low level, the light-emitting diode of the optocoupler chip OP in the detection circuit does not conduct, and the corresponding triode is cut off, and the feedback signal Bfb is pulled up to a high level. When the detection signal Qg sent by the main control chip is at a high level, the light-emitting diode of the optocoupler chip OP in the detection circuit does not conduct, and the corresponding triode is cut off, and the feedback signal Bfb is pulled up to a high level.

[0061] When the power MOS transistor Q is open, when the detection signal Qg sent by the main control chip is at a low level, the light-emitting diode of the optocoupler chip OP in the detection circuit does not conduct, and the corresponding triode is cut off, and the feedback signal Bfb is pulled up to a high level. When the detection signal Qg sent by the main control chip is at a high level, the light-emitting diode of the optocoupler chip OP in the detection circuit does not conduct, and the corresponding triode is cut off, and the feedback signal Bfb is pulled up to a high level.

[0062] Therefore, when the external braking resistor Rb or the power MOS transistor Q in the braking circuit is open and when the main control chip sends a detection signal, the received feedback signal Bfb is a high-level pulse signal with three time durations all being t.

[0063] Specific cause analysis of the second abnormal state: When the power MOS transistor Q is short-circuited, when the detection signal Qg sent by the main control chip is at a low level, the light-emitting diode of the optocoupler chip OP in the detection circuit conducts, and the corresponding triode conducts, pulling down the feedback signal Bfb to a low level. When the detection signal Qg sent by the main control chip is at a high level, the light-emitting diode of the optocoupler chip OP in the detection circuit conducts, and the corresponding triode conducts, pulling down the feedback signal Bfb to a low level.

[0064] Therefore, when the power MOS transistor Q in the braking circuit is short-circuited and when the main control chip sends a detection signal, the received feedback signal Bfb is a low-level pulse signal with three time durations all being t.

[0065] Specific cause analysis of the normal state: For example, the detection signal Qg is a pulse signal with three time durations all being t, which are a low level, a high level, and a low level respectively.

[0066] When the detection signal Qg is at a low level, the power MOS transistor Q is turned off, the light-emitting diode of the optocoupler chip OP in the detection circuit does not conduct, and the corresponding triode is cut off, pulling up the feedback signal Bfb to a high level.

[0067] When the detection signal Qg is at a high level, the power MOS transistor Q conducts, the light-emitting diode of the optocoupler chip OP in the detection circuit conducts, and the corresponding triode conducts, pulling down the feedback signal Bfb to a low level. Therefore, in the normal state, when the main control chip sends the detection signal Qg, the received feedback signal Bfb is a pulse signal with three time durations all being t, which are a high level, a low level, and a high level respectively.

[0068] Through the above solution, the present application provides a clear and operable logic for parsing the state information contained in the first feedback signal. It uses the pulse pattern of the feedback signal within a specific time window as the diagnostic basis, effectively classifying the circuit state into normal and different types of abnormalities, and associating clear response actions (fault warning / reporting or braking activation). Thereby, the problem of how to accurately judge the state of the servo drive braking circuit according to the first feedback signal output by the detection circuit and execute corresponding actions when the bus voltage of the servo drive reaches the braking activation threshold is solved, improving the reliability and fault diagnosis ability of the servo drive braking circuit.

[0069] In some embodiments, referring to the attached Figure 5, in step S3, the steps of judging the state of the servo drive braking circuit according to the second feedback signal and performing corresponding actions include: S31. If the continuous three pulse times of the second feedback signal are all high - level pulse signals, it is judged that the servo drive braking circuit is in the third abnormal state, a fault warning is issued and the third fault type is reported; S32. If the continuous three pulse times of the second feedback signal are all low - level pulse signals, it is judged that the servo drive braking circuit is in the fourth abnormal state, a fault warning is issued and the fourth fault type is reported; S33. If the continuous three pulse times of the second feedback signal are pulse signals with alternating low - level and high - level pulse signals, it is judged that the servo drive braking circuit is in the normal state, and step S1 is returned to for execution.

[0070] Further, the third fault type is that the external braking resistor or power MOS transistor in the servo drive braking circuit is open - circuited.

[0071] Further, the fourth fault type is that the power MOS transistor in the servo drive braking circuit is short - circuited.

[0072] Among them, the second feedback signal refers to the electrical signal output by the detection circuit according to the second detection signal sent by the main control chip and the state change of the braking circuit. This signal reflects the response of the braking circuit when receiving a specific test signal and can be implemented by the output signal of an optocoupler chip. The three pulse times refer to the level states of the second feedback signal output by the detection circuit within the corresponding three unit pulse time periods during the period when the main control chip sends the second detection signal (for example, low - high alternating pulses within three unit pulse times). The high - level pulse signal means that the voltage of the second feedback signal is in the high - level state within a specific pulse time period. The low - level pulse signal means that the voltage of the second feedback signal is in the low - level state within a specific pulse time period. The third abnormal state refers to a specific fault mode of the servo drive braking circuit, corresponding to the situation where the continuous three pulse times of the second feedback signal are all high - level. The third fault type refers to the specific fault category corresponding to the third abnormal state, such as the external braking resistor or power MOS transistor being open - circuited. The fourth abnormal state refers to another specific fault mode of the servo drive braking circuit, corresponding to the situation where the continuous three pulse times of the second feedback signal are all low - level. The fourth fault type refers to the specific fault category corresponding to the fourth abnormal state, such as the power MOS transistor being short - circuited. The normal state means that the servo drive braking circuit functions normally and can work according to the design requirements.

[0073] Specifically, when the bus voltage of the servo driver is lower than the preset braking function shutdown threshold, the system enters the braking circuit state detection process in the non-braking state. The main control chip sends a specific second detection signal (for example, a low-high alternating pulse sequence) to the drive circuit, and the drive circuit attempts to control the state of the power MOS transistor according to this signal. The detection circuit monitors the state change of the braking circuit (for example, through the voltage change on the state detection resistor), and converts this state change into a second feedback signal and outputs it to the main control chip. The main control chip receives and analyzes the level pattern of the second feedback signal within three consecutive pulse times. If the signal levels within these three pulse times are all high, it indicates that the braking circuit is in the third abnormal state, and the system will issue a fault warning and report the third fault type. If the signal levels within these three pulse times are all low, it indicates that the braking circuit is in the fourth abnormal state, and the system will issue a fault warning and report the fourth fault type. If the signal levels within these three pulse times show an alternating pattern of low and high levels, corresponding to the pattern of the second detection signal sent by the main control chip, it is determined that the braking circuit is in a normal state. After being determined to be in a normal state, since the bus voltage is lower than the braking function shutdown threshold, no braking operation is required, and the system returns to the initial step of periodically sampling the bus voltage, continues to monitor the bus voltage, and waits for the next judgment on whether to activate braking. In this way, even when braking is not required, the system can actively detect potential faults in the braking circuit, especially those fault modes that may cause continuous conduction, thereby improving the reliability of the system. This detection mechanism utilizes the added state detection resistor and detection circuit in the servo drive braking circuit, and combines the ability of the main control chip to send test signals and receive feedback signals, making it possible to perform fault diagnosis in the non-braking state.

[0074] Specifically, the specific cause analysis of the third abnormal state is the same as the specific cause analysis of the first abnormal state in the above embodiment, and will not be elaborated here.

[0075] Specifically, the specific cause analysis of the fourth abnormal state is the same as the specific cause analysis of the second abnormal state in the above embodiment, and will not be elaborated here.

[0076] In this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0077] The description with reference to terms such as "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the illustrative representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0078] The above are only examples of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A servo drive braking circuit, comprising a main circuit (100) and a drive circuit (200), the drive circuit (200) being connected to the main circuit (100) and being used to drive a servo driver connected to the main circuit (100) to perform braking, characterized in that, It further includes a main control chip (300) and a detection circuit (400). The main circuit includes a power MOS transistor (Q), a freewheeling diode (Dx), a state detection resistor (Ra), and an external braking resistor (Rb). Among them, the gate of the power MOS transistor (Q) is connected to the drive circuit (200); the source of the power MOS transistor (Q) is connected to one end of the state detection resistor (Ra), and the other end of the state detection resistor (Ra) is connected to the servo driver; the source of the power MOS transistor (Q) is also connected to the detection circuit (400), the drain of the power MOS transistor (Q) is simultaneously connected to the positive electrode of the freewheeling diode (Dx) and one end of the external braking resistor (Rb), and the other end of the external braking resistor (Rb) is simultaneously connected to the negative electrode of the freewheeling diode (Dx) and the servo driver; the detection circuit (400) can communicate with the drive circuit (200) through the main control chip (300).

2. The servo drive braking circuit according to claim 1, wherein The resistance of the state detection resistor satisfies the following conditions: ； Wherein, is the resistance of the state detection resistor (Ra), is the bus voltage of the servo driver, is the loop current when the main circuit (100) operates normally, is the resistance of the external braking resistor (Rb), and the is the on-resistance of the power MOS transistor (Q).

3. The servo drive braking circuit according to claim 1, wherein, The drive circuit (200) includes a drive chip (210), a first resistor (R1), a second resistor (R2), and a first diode (D1). Among them, the drive chip (210) is used to receive the detection signal (Qg) sent by the main control chip (300). The drive chip (210) is simultaneously connected to the first end of the first resistor (R1) and the first end of the second resistor (R2). The second end of the second resistor (R2) is connected to the negative electrode of the first diode (D1), and the positive electrode of the first diode (D1) is connected to the second end of the first resistor (R1) and is used to output a drive signal (Qgb).

4. The servo drive braking circuit according to claim 1, characterized in that, The detection circuit (400) includes a third resistor (R3), an optocoupler chip (OP), and a fourth resistor (R4). Among them, the first end of the third resistor (R3) is used to receive the electrical signal sent by the state detection resistor (Ra). The second end of the third resistor (R3) is connected to the positive electrode of the diode side of the optocoupler chip (OP), and the negative electrode of the diode side of the optocoupler chip (OP) is grounded; the collector of the transistor side of the optocoupler chip (OP) is connected to the first end of the fourth resistor (R4), the second end of the fourth resistor (R4) is used to output a supply voltage (Vcc), and the collector of the transistor side of the optocoupler chip (OP) is also used to output a feedback signal (Bfb) to the main control chip (300); the emitter of the transistor side of the optocoupler chip (OP) is grounded.

5. The servo drive braking circuit according to claim 4, characterized in that The conduction current of the diode side of the optocoupler chip (OP) satisfies the following conditions: ； ； ； Among them, is the conduction current on the diode side of the optocoupler chip (OP), is the voltage across both ends of the state detection resistor (Ra), is the preset conduction voltage, is the resistance of the third resistor (R3), is the resistance of the state detection resistor (Ra), is the preset desired resistor power.

6. A servo driver control method based on the servo drive braking circuit according to any one of claims 1-5, characterized in that, It includes the following steps: S1. Periodically sample the bus voltage of the servo driver. S2. Compare the bus voltage of the servo driver with a preset braking function activation threshold. When the bus voltage of the servo driver is greater than or equal to the braking function activation threshold, control the main control chip to send a first detection signal to enable the detection circuit to output a first feedback signal, and judge the state of the servo drive braking circuit according to the first feedback signal, and perform corresponding actions; the first detection signal is a pulse signal in which a low-level pulse signal and a high-level pulse signal alternate according to a unit pulse time. S3. Compare the bus voltage of the servo driver with a preset braking function deactivation threshold. When the bus voltage of the servo driver is less than the braking function deactivation threshold, control the main control chip to send a second detection signal to enable the detection circuit to output a second feedback signal, and judge the state of the servo drive braking circuit according to the second feedback signal, and perform corresponding actions; the second detection signal is a pulse signal in which a low-level pulse signal and a high-level pulse signal alternate according to a unit pulse time.

7. The servo driver control method according to claim 6, characterized in that In step S2, the steps of judging the state of the servo drive braking circuit according to the first feedback signal and performing corresponding actions include: S21. If the continuous three pulse times of the first feedback signal are all high-level pulse signals, it is judged that the servo drive braking circuit is in a first abnormal state, issue a fault warning and report the first fault type; S22. If the continuous three pulse times of the first feedback signal are all low-level pulse signals, it is judged that the servo drive braking circuit is in a second abnormal state, issue a fault warning and report the second fault type; S23. If the continuous three pulse times of the first feedback signal are pulse signals that alternate between low-level pulse signals and high-level pulse signals, it is judged that the servo drive braking circuit is in a normal state, and the braking function is activated.

8. The servo drive control method according to claim 7, wherein, In step S3, the steps of judging the state of the servo drive braking circuit according to the second feedback signal and performing corresponding actions include: S31. If the continuous three pulse times of the second feedback signal are all high-level pulse signals, it is judged that the servo drive braking circuit is in a third abnormal state, issue a fault warning and report the third fault type; S32. If the continuous three pulse times of the second feedback signal are all low-level pulse signals, it is judged that the servo drive braking circuit is in a fourth abnormal state, issue a fault warning and report the fourth fault type; S33. If the continuous three pulse times of the second feedback signal are pulse signals that alternate between low-level pulse signals and high-level pulse signals, it is judged that the servo drive braking circuit is in a normal state, and return to execute step S1.

9. The servo driver control method according to claim 8, characterized in that Both the first fault type and the third fault type are that the external braking resistor or the power MOS transistor in the servo drive braking circuit is open.

10. The servo drive control method according to claim 8, wherein Both the second fault type and the fourth fault type are that the power MOS transistor in the servo drive braking circuit is short-circuited.

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