A motor brake state detection circuit and disconnection detection method

Abstract

The present invention discloses a motor brake state detection circuit and a line break detection method. The circuit includes a motor brake control circuit, which is used to control the operating state of the motor brake according to an input control signal; a pulse generating unit is provided in the motor brake control circuit, and the state detection circuit also includes a motor brake output voltage detection circuit, and the two input ends of the output voltage detection circuit are respectively connected to the two output ends of the motor brake control circuit, and are used to output a brake state feedback signal. The motor brake state detection circuit provided by the present invention adds a motor brake output voltage detection circuit, and the circuit structure is simple, and can output a brake state feedback signal during the operation of the servo drive; and then the motor brake state detection circuit is applied, and according to the line break detection method provided, it is possible to effectively detect whether the motor brake coil is broken, so as to avoid the motor from being damaged by continuous operation of the motor when the motor brake is in a braking state.

Description

Technical Field

[0001] The present application relates to the technical field of motor brakes, and in particular to a motor brake state detection circuit and a wire break detection method. Background Art

[0002] In the servo system of industrial robots, motors with brake functions are usually selected as drive motors. At present, the common practice is that the servo driver is equipped with a motor brake circuit, such as Figure 1 As shown (M refers to the motor), the motor brake circuit includes a motor brake control circuit, wherein the brake switch device is a relay, and the motor brake is controlled by the motor brake control circuit, so that the motor brake coil is energized and the brake is released, and the motor brake coil is de-energized and the brake is braked.

[0003] The motor brake control circuit in the prior art is often controlled by a digital output circuit, that is, the motor brake output power is controlled by closing or opening a switch to release or brake the motor. However, the above motor brake control circuit uses a simple switch, so the reliability is poor; and if the motor brake has no output or is disconnected, it is often difficult to detect in time through the existing motor brake circuit, which can easily cause the motor to be forced to run when the motor brake is in a braking state, thereby damaging the motor. Summary of the invention

[0004] Based on this, in order to solve the above technical problems, an embodiment of the present invention provides a motor brake state detection circuit and a wire break detection method.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In the first aspect, a motor brake state detection circuit includes a motor brake control circuit, which is used to control the operating state of the motor brake according to an input brake control signal INPUT, so that the motor brake coil is energized to release the brake and the motor brake coil is de-energized to brake; a pulse generating unit is provided in the motor brake control circuit, and the motor brake state detection circuit also includes a motor brake output voltage detection circuit, and two input ends of the motor brake output voltage detection circuit are respectively connected to two output ends of the motor brake control circuit, and are used to output a brake state feedback signal STATUS according to the detected effective brake voltage.

[0007] Preferably, the motor brake control circuit includes a resistor R1, a resistor R2, a MOSFET Q1, a MOSFET Q2 and a transient diode TVS; the source of the MOSFET Q1 is connected to the positive electrode of the power supply, and the drain of the MOSFET Q1 is connected to one end of the motor brake coil; the source of the MOSFET Q2 is connected to the negative electrode of the power supply, and the drain of the MOSFET Q2 is connected to the other end of the motor brake coil; one end of the transient diode TVS is connected to the drain of the MOSFET Q1, and the other end is connected to the drain of the MOSFET Q2.

[0008] Further preferably, the input end of the motor brake control circuit is provided with an isolation optocoupler U1, and the input end of the isolation optocoupler U1 is used to receive the brake control signal INPUT; one end of the resistor R1 is connected to the positive electrode of the power supply, and the other end is connected to the collector of the output end of the isolation optocoupler U1; one end of the resistor R2 is connected to the negative electrode of the power supply, and the other end is connected to the emitter of the output end of the isolation optocoupler U1; the gate of the metal oxide semi-field effect transistor Q1 is connected to the collector of the output end of the isolation optocoupler U1, and the gate of the metal oxide semi-field effect transistor Q2 is connected to the emitter of the output end of the isolation optocoupler U1.

[0009] Further preferably, the motor brake output voltage detection circuit includes an isolation optocoupler U2, a resistor R3, a voltage regulator Z1 and a rectifier bridge D1, wherein the output end of the isolation optocoupler U2 is used to output a brake status feedback signal STATUS; one end of the resistor R3 is connected to the positive electrode of the input end of the isolation optocoupler U2, and the other end is connected to the positive electrode of the output end of the rectifier bridge D1; the positive electrode of the voltage regulator Z1 is connected to the negative electrode of the output end of the rectifier bridge D1, and the negative electrode of the voltage regulator Z1 is connected to the negative electrode of the input end of the isolation optocoupler U2; the two input ends of the rectifier bridge D1 are respectively connected to the drain of the metal oxide semi-conductor field effect transistor Q1 and the drain of the metal oxide semi-conductor field effect transistor Q2, for rectifying the detected effective voltage and then outputting an effective level; the motor brake output voltage detection circuit will output a brake status feedback signal STATUS according to the effective level.

[0010] Further preferably, a positive 24V voltage is loaded on one end of the resistor R1 and the source of the MOSFET Q1 , and a negative 24V voltage is loaded on one end of the resistor R2 and the source of the MOSFET Q2 .

[0011] Further preferably, the effective voltage value of the output brake state feedback signal STATUS is set by adjusting parameters of the resistor R3 and the voltage stabilizing diode Z1.

[0012] In a second aspect, a motor brake disconnection detection method is provided, using the motor brake state detection circuit described in the first aspect, the method comprising:

[0013] Step 1, receiving an input brake control signal INPUT, and setting a pulse signal in the brake control signal INPUT;

[0014] Step 2: output brake status feedback signal STATUS;

[0015] Step three: determine whether the motor brake coil is broken. If so, output an alarm prompt.

[0016] Preferably, the brake control signal INPUT in step one is a level signal; and setting a pulse signal in the brake control signal INPUT is specifically to add a pulse signal to the level signal of the brake control signal INPUT through a pulse generating unit.

[0017] Further preferably, the pulse width of the added pulse signal is less than 10 ms.

[0018] Further preferably, the step of determining whether the motor brake coil is broken in step 3 is as follows:

[0019] According to the characteristics of the motor brake coil, for the pulse signal part added to the input brake control signal INPUT, the brake status feedback signal STATUS has no pulse signal returned, indicating that the motor brake is connected and the motor brake coil is not broken; for the pulse signal part added to the input brake control signal INPUT, the brake status feedback signal STATUS has a pulse signal returned and keeps synchronized with the input brake control signal INPUT, indicating that the motor brake is not connected and the motor brake coil is broken.

[0020] The present invention has at least the following beneficial effects:

[0021] The motor brake state detection circuit provided by the present invention adds a motor brake state detection circuit compared to the currently commonly used motor brake circuit. While ensuring the simplicity of the circuit structure, it can detect the effective voltage at both ends of the brake during the operation of the servo driver and output a brake state feedback signal; further, by applying the motor brake state detection circuit, through the provided wire break detection method, it is possible to effectively detect whether the motor brake coil is broken, thereby avoiding damage to the motor caused by continuous operation of the motor when the motor brake is in a braking state.

[0022] The present invention also improves the traditional motor brake control circuit. Unlike the traditional method of using a relay as a circuit switching device, the present invention uses two metal oxide semi-conductor field effect transistors as circuit dual switching devices to control the braking and releasing of the motor brake, thereby reducing the probability of incorrect release of the brake and improving the reliability of the motor brake control. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural diagram of an existing motor brake circuit;

[0024] Figure 2 An overall structural diagram of a motor brake state detection circuit provided by an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the specific internal structure of a motor brake state detection circuit provided by an embodiment of the present invention;

[0026] Figure 4 A schematic flow chart of a method for detecting a motor brake disconnection provided by an embodiment of the present invention;

[0027] Figure 5 A schematic diagram of a brake control signal INPUT and a brake state feedback signal STATUS when a motor brake is not disconnected is provided in an embodiment of the present invention;

[0028] Figure 6 An embodiment of the present invention provides a schematic diagram of a brake control signal INPUT and a brake state feedback signal STATUS when a motor brake is disconnected. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0030] Embodiment 1:

[0031] In the embodiment of the present invention, Figure 2 As shown, a motor brake state detection circuit is provided, including a motor brake control circuit, which is used to control the operating state of the motor brake according to an input brake control signal INPUT. When the motor brake control circuit is turned on, the motor brake coil is energized and the brake is released; when the motor brake control circuit is not turned on, the motor brake coil is de-energized and the brake is braked; a pulse generating unit is provided in the motor brake control circuit, and the motor brake state detection circuit also includes a motor brake output voltage detection circuit, and two input ends of the motor brake output voltage detection circuit are respectively connected to two output ends of the motor brake control circuit, and are used to output a brake state feedback signal STATUS according to the detected effective brake voltage.

[0032] Specifically, Figure 3As shown, the motor brake control circuit includes a resistor R1, a resistor R2, a metal oxide semiconductor field effect transistor (MOS tube) Q1, a metal oxide semiconductor field effect transistor (MOS tube) Q2 and a transient diode TVS; the source of the metal oxide semiconductor field effect transistor Q1 is connected to the positive electrode of the power supply, and the drain of the metal oxide semiconductor field effect transistor Q1 is connected to one end of the motor brake coil; the source of the metal oxide semiconductor field effect transistor Q2 is connected to the negative electrode of the power supply, and the drain of the metal oxide semiconductor field effect transistor Q2 is connected to the other end of the motor brake coil; one end of the transient diode TVS is connected to the drain of the metal oxide semiconductor field effect transistor Q1, and the other end is connected to the drain of the metal oxide semiconductor field effect transistor Q2.

[0033] Furthermore, if Figure 3 As shown, the input end of the motor brake control circuit is provided with an isolation optocoupler U1, and the input end of the isolation optocoupler U1 is used to receive the brake control signal INPUT; one end of the resistor R1 is connected to the positive electrode of the power supply, and the other end is connected to the collector of the output end of the isolation optocoupler U1; one end of the resistor R2 is connected to the negative electrode of the power supply, and the other end is connected to the emitter of the output end of the isolation optocoupler U1; the gate of the metal oxide semi-field effect transistor Q1 is connected to the collector of the output end of the isolation optocoupler U1, and the gate of the metal oxide semi-field effect transistor Q2 is connected to the emitter of the output end of the isolation optocoupler U1.

[0034] Specifically, when the input end of the isolation optocoupler U1 has the input brake control signal INPUT, the isolation optocoupler U1 turns on the MOS transistor Q1 and the MOS transistor Q2, that is, the MOS transistor Q1 and the MOS transistor Q2 act as two switching devices in the circuit. When the MOS transistor Q1 and the MOS transistor Q2 are turned on, there will be voltage at both ends of the motor brake, and BK+ and BK- will output the brake voltage; conversely, when the input end of the isolation optocoupler U1 does not have the input brake control signal INPUT, BK+ and BK- have no voltage output.

[0035] Furthermore, if Figure 3 As shown, the motor brake output voltage detection circuit includes an isolation optocoupler U2, a resistor R3, a voltage regulator Z1 and a rectifier bridge D1, wherein the output end of the isolation optocoupler U2 is used to output a brake state feedback signal STATUS; one end of the resistor R3 is connected to the positive electrode of the input end of the second isolation optocoupler U2, and the other end is connected to the positive electrode of the output end of the rectifier bridge D1; the positive electrode of the voltage regulator Z1 is connected to the negative electrode of the output end of the rectifier bridge D1, and the negative electrode of the voltage regulator Z1 is connected to the negative electrode of the input end of the isolation optocoupler U2; the two input ends of the rectifier bridge D1 are respectively connected to the drain of the MOS tube Q1 and the drain of the MOS tube Q2, for rectifying the detected effective voltage and then outputting an effective level. Further, the motor brake output voltage detection circuit will output a brake state feedback signal STATUS according to the effective level.

[0036] Specifically, a positive 24V voltage is applied to one end of the resistor R1 and the source of the MOSFET Q1 , and a negative 24V voltage is applied to one end of the resistor R2 and the source of the MOSFET Q2 .

[0037] Furthermore, the effective voltage value of the output brake state feedback signal STATUS is set by adjusting the parameters of the resistor R3 and the voltage stabilizing diode Z1.

[0038] The motor brake state detection circuit provided by the embodiment of the present invention, compared with the currently commonly used motor brake circuit, adds a motor brake output voltage detection circuit, while ensuring the simplicity of the circuit structure, can detect the effective voltage at both ends of the brake during the operation of the servo driver, output the brake state feedback signal, and can provide a basis for further judging whether the motor brake is broken. The motor brake state detection circuit also improves the traditional motor brake control circuit. Unlike the traditional use of a relay as a circuit switch device, two MOS tubes are used as circuit dual switch devices to control the braking and release of the motor brake, which reduces the probability of erroneous release of the brake and improves the reliability of the motor brake control.

[0039] Embodiment 2:

[0040] In this embodiment, if Figure 4 As shown, a motor brake disconnection detection method is provided, which uses the motor brake state detection circuit provided in the first embodiment, including the following steps:

[0041] Step S401, receiving an input brake control signal INPUT, and setting a pulse signal in the brake control signal INPUT;

[0042] Step S402, outputting a brake status feedback signal STATUS;

[0043] Step S403, determine whether the motor brake coil is broken, and if so, output an alarm prompt.

[0044] Specifically, the brake control signal INPUT in step S401 is a valid level signal; and setting a pulse signal in the brake control signal INPUT is specifically to add a pulse signal to the level signal of the brake control signal INPUT through a pulse generating unit.

[0045] Furthermore, the pulse width of the added pulse signal is less than 10 ms.

[0046] Further, the determination of whether the motor brake coil is disconnected in step S403 is specifically:

[0047] According to the characteristics of the motor brake coil, such as Figure 5 As shown, for the pulse signal part added to the input brake control signal INPUT, the brake status feedback signal STATUS has no pulse signal returned, indicating that the motor brake has been connected and the motor brake coil is not disconnected. In other words, when the motor brake is connected, in the short moment when the input level signal is at a low level, that is, in the short time when the motor brake control circuit is not turned on, according to the characteristics of the motor brake coil, the brake coil will store some energy, and the stored energy can supply voltage to the coil for tens of milliseconds to hundreds of milliseconds; that is to say, when the motor brake is connected, at the moment when the motor brake control circuit is not turned on, there is still voltage at both ends of the motor brake, so the brake status feedback signal STATUS will still maintain the state when the motor brake control circuit is turned on, and will not have a low-level output due to the input pulse signal being at a low level for a moment.

[0048] Similarly, if Figure 6 As shown in the figure, for the pulse signal part added to the input brake control signal INPUT, the brake status feedback signal STATUS has a pulse signal returned, which is consistent with the input pulse signal, indicating that the motor brake is not connected and the motor brake coil is disconnected. In other words, when the motor brake is not connected, due to the absence of the brake coil, during the short moment when the input level signal is at a low level, that is, during the short time when the motor brake control circuit is not turned on, the brake status feedback signal STATUS will also be at a low level for a moment.

[0049] In summary, it is possible to determine whether the motor brake coil is broken and give a warning when it is broken.

[0050] The motor brake disconnection detection method provided in the embodiment of the present invention applies the motor brake state detection circuit provided in the first embodiment, combined with the brake control signal and the brake state feedback signal of the detection circuit, to achieve effective detection of whether the motor brake coil is disconnected, thereby avoiding damage to the motor due to forced continuous operation of the motor when the motor brake is in a braking state.

[0051] It should be understood that although Figure 4 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 4At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0052] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0053] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for detecting a motor brake disconnection, characterized in that: Applied to a motor brake state detection circuit, the motor brake state detection circuit includes a motor brake control circuit, which is used to control the operating state of the motor brake according to an input brake control signal INPUT, and two output ends of the motor brake control circuit are respectively connected to the two ends of the brake, so that the motor brake coil is energized to release the brake, and the motor brake coil is de-energized to brake; a pulse generating unit is provided in the motor brake control circuit, and the motor brake state detection circuit also includes a motor brake output voltage detection circuit, and two input ends of the motor brake output voltage detection circuit are respectively connected to two output ends of the motor brake control circuit, and are used to output a brake state feedback signal STATUS according to the effective voltage detected at both ends of the brake; The method comprises: Step 1: inputting a brake control signal INPUT into the motor brake control circuit, wherein the brake control signal INPUT is a level signal; adding a pulse signal to the level signal of the brake control signal INPUT through the pulse generating unit; Step 2: the motor brake output voltage detection circuit outputs a brake state feedback signal STATUS; Step 3: Determine whether the motor brake coil is disconnected. If so, output an alarm prompt; The determination of whether the motor brake coil is broken in step 3 is as follows: According to the characteristics of the motor brake coil, for the pulse signal part added to the input brake control signal INPUT, the brake status feedback signal STATUS has no pulse signal returned, indicating that the motor brake is connected and the motor brake coil is not broken; for the pulse signal part added to the input brake control signal INPUT, the brake status feedback signal STATUS has a pulse signal returned and keeps synchronized with the input brake control signal INPUT, indicating that the motor brake is not connected and the motor brake coil is broken.

2. The motor brake disconnection detection method according to claim 1, characterized in that: The motor brake control circuit includes a resistor R1, a resistor R2, a metal oxide semi-conductor field effect transistor Q1, a metal oxide semi-conductor field effect transistor Q2 and a transient diode TVS; the source of the metal oxide semi-conductor field effect transistor Q1 is connected to the positive electrode of the power supply, and the drain of the metal oxide semi-conductor field effect transistor Q1 is connected to one end of the motor brake coil; the source of the metal oxide semi-conductor field effect transistor Q2 is connected to the negative electrode of the power supply, and the drain of the metal oxide semi-conductor field effect transistor Q2 is connected to the other end of the motor brake coil; one end of the transient diode TVS is connected to the drain of the metal oxide semi-conductor field effect transistor Q1, and the other end is connected to the drain of the metal oxide semi-conductor field effect transistor Q2; An isolation optocoupler U1 is provided at the input end of the motor brake control circuit, and the input end of the isolation optocoupler U1 is used to receive a brake control signal INPUT; one end of the resistor R1 is connected to the positive electrode of the power supply, and the other end is connected to the collector of the output end of the isolation optocoupler U1; one end of the resistor R2 is connected to the negative electrode of the power supply, and the other end is connected to the emitter of the output end of the isolation optocoupler U1; the gate of the metal oxide semi-field effect transistor Q1 is connected to the collector of the output end of the isolation optocoupler U1, and the gate of the metal oxide semi-field effect transistor Q2 is connected to the emitter of the output end of the isolation optocoupler U1.

3. The motor brake disconnection detection method according to claim 2, characterized in that: The motor brake output voltage detection circuit includes an isolation optocoupler U2, a resistor R3, a voltage regulator Z1 and a rectifier bridge D1, wherein the output end of the isolation optocoupler U2 is used to output a brake status feedback signal STATUS; one end of the resistor R3 is connected to the positive electrode of the input end of the isolation optocoupler U2, and the other end is connected to the positive electrode of the output end of the rectifier bridge D1; the positive electrode of the voltage regulator Z1 is connected to the negative electrode of the output end of the rectifier bridge D1, and the negative electrode of the voltage regulator Z1 is connected to the negative electrode of the input end of the isolation optocoupler U2; the two input ends of the rectifier bridge D1 are respectively connected to the drain of the metal oxide semi-conductor field effect transistor Q1 and the drain of the metal oxide semi-conductor field effect transistor Q2, for rectifying the detected effective voltage and then outputting an effective level; the motor brake output voltage detection circuit will output a brake status feedback signal STATUS according to the effective level.

4. The motor brake disconnection detection method according to claim 3, characterized in that: A positive 24V voltage is applied to one end of the resistor R1 and the source of the MOSFET Q1 , and a negative 24V voltage is applied to one end of the resistor R2 and the source of the MOSFET Q2 .

5. The motor brake disconnection detection method according to claim 3, characterized in that: The effective voltage value of the output brake state feedback signal STATUS is set by adjusting the parameters of the resistor R3 and the voltage stabilizing diode Z1.

6. The motor brake disconnection detection method according to claim 1, characterized in that: The pulse width of the added pulse signal is less than 10 ms.

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