Control device of brushless DC servo motor and distributed servo system

Abstract

The utility model provides a kind of control device and distributed rudder system of brushless DC servo motor, comprising: microprocessor, motor drive circuit, current detection circuit, position sensor interface and bus communication circuit respectively with microprocessor electric connection;Motor drive circuit input and output respectively electric connection microprocessor and brushless DC motor in brushless DC servo motor;Current detection circuit is connected in series in the loop of motor drive circuit and the armature winding of brushless DC motor, and the output of current detection circuit is connected with microprocessor;The input of position sensor interface is connected with the position sensor on the output shaft of brushless DC servo motor, and the output of position sensor interface is connected with microprocessor, without through the link of host computer and sensor to constitute closed-loop control, shorten feedback link, improve the stability of brushless DC servo motor operation.

Description

Technical Field

[0001] This utility model relates to the field of servo control technology, specifically to a control device for a brushless DC servo and a distributed servo system. Background Technology

[0002] Servo motors, as servo drives providing precise angle control, are widely used in robotics, industrial automation, and intelligent models. Traditional servo motor control systems mostly use brushed DC motors, and their control primarily relies on pulse width modulation (PWM) signals issued by a host computer. However, the control devices for these brushless DC servos typically achieve closed-loop control by establishing a link between the host computer and the sensors on the brushless DC servo. However, the relatively long path between the host computer and the sensors on the brushless DC servo reduces the operational stability of the brushless DC servo.

[0003] Therefore, there is an urgent need in the field for a servo control device that can shorten the link between the servo and the sensor on the brushless DC servo, so as to improve the stability of the operation of the brushless DC servo. Utility Model Content

[0004] In view of this, it is necessary to provide a control device and a distributed servo system for a brushless DC servo to solve the technical problem that the long path between the host computer and the sensors on the brushless DC servo reduces the stability of the brushless DC servo operation in the prior art.

[0005] To solve the above-mentioned technical problems, in a first aspect, this utility model provides a control device for a brushless DC servo motor, comprising: The microprocessor, a motor drive circuit, a current detection circuit, a position sensor interface, and a bus communication circuit, all electrically connected to the microprocessor; The input and output terminals of the motor drive circuit are electrically connected to the microprocessor and the brushless DC motor in the brushless DC servo motor, respectively. The current detection circuit is connected in series in the circuit of the motor drive circuit and the armature winding of the brushless DC motor, and the output terminal of the current detection circuit is connected to the microprocessor. The input terminal of the position sensor interface is connected to a position sensor mounted on the output shaft of the brushless DC servo motor, and the output terminal of the position sensor interface is connected to the microprocessor.

[0006] In one possible implementation, the bus communication circuit is a CAN FD communication circuit, which includes a CAN FD transceiver chip connected to the microprocessor.

[0007] In one possible implementation, the position sensor interface is a hardware SPI interface or a hardware IIC interface.

[0008] In one possible implementation, the motor drive circuit and the current detection circuit are integrated into the motor drive chip.

[0009] In one possible implementation, an external sensor interface electrically connected to the microprocessor is also included. The external sensor interface is an IIC interface or an SPI interface, used to connect a pressure sensor or a displacement sensor.

[0010] In one possible implementation, a power management module is also included. The input terminal of the power management module is used to connect to an external power source, and the output terminal of the power management module is connected to the microprocessor, the motor drive circuit, the position sensor interface, the external sensor interface, and the bus communication circuit for power supply.

[0011] In one possible implementation, the microprocessor is connected to an external crystal oscillator.

[0012] Secondly, this utility model provides a distributed servo motor system, comprising: A host computer; At least two control devices for brushless DC servos as described in any one of the first aspects, each of the control devices serving as an intelligent node; A shared bus communication link; The host computer and all the intelligent nodes are connected to the shared bus communication link.

[0013] In one possible implementation, the shared bus communication link is a CAN FD bus.

[0014] The beneficial effects of this utility model are: The control device for a brushless DC servo provided by this utility model includes: a microprocessor, a motor drive circuit, a current detection circuit, a position sensor interface, and a bus communication circuit, all electrically connected to the microprocessor. The input and output terminals of the motor drive circuit are electrically connected to the microprocessor and the brushless DC motor in the brushless DC servo, respectively. The current detection circuit is connected in series in the circuit of the motor drive circuit and the armature winding of the brushless DC motor, and the output terminal of the current detection circuit is connected to the microprocessor to form a current feedback path. The input terminal of the position sensor interface is connected to a position sensor installed on the output shaft of the brushless DC servo, and the output terminal of the position sensor interface is connected to the microprocessor, forming a position and speed feedback link. This eliminates the need for closed-loop control through a link between a host computer and the sensor, greatly shortening the feedback link, reducing the difficulty of control feedback in practical applications of the brushless DC servo, and improving the operational stability of the brushless DC servo. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of an embodiment of the control device for the brushless DC servo motor provided by this utility model; Figure 2 A schematic diagram of another embodiment of the control device for the brushless DC servo motor provided by this utility model; Figure 3 This is a schematic diagram of an embodiment of the distributed servo system provided by this utility model. Detailed Implementation

[0017] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0018] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0019] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature include the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature include the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. In the description of this embodiment, the terms "above," "below," "left," and "right," etc., are based on the orientation or positional relationship shown in the drawings, and are only for ease of description and simplification of operation, not to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0020] Through research, the inventors discovered that the brushless DC motor servo control device in related technologies mainly relies on the host computer to send PWM signals for control communication, which requires a separate microprocessor I / O port for communication. Furthermore, the brushless DC motor-based servo control system suffers from a large circuit area due to the complexity of the external drive circuit, and the long path between the host computer and the sensors on the brushless DC servo increases the difficulty of control feedback in practical applications. Moreover, it typically lacks the ability to connect external sensors, making it impossible to achieve closed-loop control between receiving servo rotation position commands and the actual displacement of the external transmission device on the microprocessor inside the servo.

[0021] To address the aforementioned problems, this invention provides a control device for a brushless DC servo motor and a distributed servo motor system, which will be described in detail below.

[0022] Figure 1 A schematic diagram of an embodiment of the control device for the brushless DC servo motor provided by this utility model is shown below. Figure 1 As shown, the control device for the brushless DC servo motor includes: The microprocessor 10, the motor drive circuit 20, the current detection circuit 30, the position sensor interface 40, and the bus communication circuit 50 are all electrically connected to the microprocessor 10.

[0023] In this embodiment, the brushless DC servo motor includes a brushless DC motor, a reduction gearbox, a feedback sensor board, a main control drive circuit board, and a housing. The microprocessor 10 serves as the control unit of the control device. The motor drive circuit 20, the current detection circuit 30, the position sensor interface 40, and the bus communication circuit 50 are all communicatively connected to the microprocessor 10; for example, the bus communication circuit 50 is connected to the bus controller pins of the microprocessor 10.

[0024] The input and output terminals of the motor drive circuit 20 are electrically connected to the microprocessor 10 and the brushless DC motor 60 in the brushless DC servo, respectively.

[0025] The motor drive circuit 20 includes a motor drive chip and its related peripheral circuits, which are used to drive the brushless DC motor 60.

[0026] Specifically, the input terminal of the motor drive circuit 20 is connected to the microprocessor 10, and the output terminal of the motor drive circuit 20 is connected to the brushless DC motor 60, which is used to drive the brushless DC motor 60 according to the instructions of the microprocessor 10.

[0027] It is worth noting that the motor drive circuit 20 is also equipped with a low-power sleep circuit and a fault alarm circuit. The output of the fault alarm circuit is connected to the general-purpose input / output pin of the microprocessor 10.

[0028] The current detection circuit 30 is connected in series in the circuit of the motor drive circuit 20 and the armature winding of the brushless DC motor 60, and the output terminal of the current detection circuit 30 is connected to the microprocessor 10.

[0029] The current detection circuit 30 is located in the circuit of the motor drive circuit 20, connected in series in the circuit between the motor drive circuit 20 and the armature winding of the brushless DC motor 60. The motor drive circuit 20 integrates a current detection circuit, such as a three-phase current detection circuit, whose output is connected to the analog-to-digital converter (ADC) pin of the microprocessor 10 to form a current feedback link.

[0030] Specifically, the output terminal of the current detection circuit 30 is connected to the current sampling input terminal of the microprocessor 10 to form a current feedback path. For example, the current signal detected by the current detection circuit 30 is fed back to the analog-to-digital converter (ADC) pin of the microprocessor 10 to form a current feedback link.

[0031] The input terminal of the position sensor interface 40 is connected to the position sensor 80 disposed on the output shaft of the brushless DC servo motor 70, and the output terminal of the position sensor interface 30 is connected to the microprocessor 10.

[0032] The position sensor 80 can be a potentiometer or a magnetic encoder.

[0033] Specifically, the input end of the position sensor interface 40 is connected to a position sensor mounted on the output shaft of the brushless DC servo motor 60, and the output end of the position sensor interface 40 is connected to the position signal input end of the microprocessor 10, which is used to detect the angle and speed of the output shaft of the brushless DC servo motor 60, thus forming a position and speed feedback link.

[0034] Understandably, the motor drive circuit 20, current detection circuit 30, position sensor interface 40, and external sensor interface 50 are all connected to the microprocessor 10. Therefore, the microprocessor 10 can obtain feedback signals from the motor drive circuit 20, current detection circuit 30, position sensor interface 40, and external sensor interface 50, and complete closed-loop control of the current loop, speed loop, and position loop of the brushless DC servo locally, i.e., at the servo end. Since the closed-loop control of the brushless DC motor 60 is performed at the servo end, there is no need to perform closed-loop control through the link formed by the host computer and the sensor, which greatly shortens the feedback link, reduces the difficulty of control feedback of the brushless DC servo in practical applications, and improves the operational stability of the brushless DC servo.

[0035] The control device for the brushless DC servo provided in this embodiment includes: a microprocessor, a motor drive circuit, a current detection circuit, a position sensor interface, and a bus communication circuit, all electrically connected to the microprocessor. The input and output terminals of the motor drive circuit are electrically connected to the microprocessor and the brushless DC motor in the brushless DC servo, respectively. The current detection circuit is connected in series in the circuit of the motor drive circuit and the armature winding of the brushless DC motor, and the output terminal of the current detection circuit is connected to the microprocessor to form a current feedback path. The input terminal of the position sensor interface is connected to a position sensor installed on the output shaft of the brushless DC servo, and the output terminal of the position sensor interface is connected to the microprocessor, forming a position and speed feedback link. The microprocessor can obtain feedback signals from the motor drive circuit, the current detection circuit, the position sensor interface, and the external sensor interface to complete closed-loop control of the current loop, speed loop, and position loop of the brushless DC motor at the servo end. This eliminates the need for closed-loop control through a link formed by a host computer and the sensor, greatly shortening the feedback link, reducing the difficulty of control feedback in practical applications of the brushless DC servo, and improving the operational stability of the brushless DC servo.

[0036] The microprocessor 10 is used to perform feedback adjustment based on feedback signals obtained from the motor drive circuit, current detection circuit, and position sensor interface, thereby realizing closed-loop control of the brushless DC motor at the servo end. In this embodiment, the feedback adjustment can be an existing feedback control algorithm, such as a PID algorithm.

[0037] In some embodiments, the bus communication circuit is a CAN FD communication circuit, which includes a CAN FD transceiver chip connected to the microprocessor.

[0038] Specifically, the CAN FD communication circuit includes a CAN FD transceiver chip connected to a microprocessor. This CAN FD transceiver chip is connected to the CAN FD controller pin of the microprocessor. Compared with the traditional CAN bus, the CAN FD protocol increases the baud rate of the data segment, ensuring real-time signal acquisition.

[0039] In some embodiments, the position sensor interface is a hardware SPI interface or a hardware IIC interface.

[0040] Specifically, the hardware SPI / IIC interface is a dedicated communication peripheral inside the microprocessor, and this hardware interface can transmit data at high speed in the background through direct memory access, hardly occupying CPU resources, thus realizing high-precision and high-resolution position signal acquisition.

[0041] In some embodiments, the position sensor includes a magnetic encoder.

[0042] Among them, the principle of magnetic encoder is usually based on Hall effect sensing to measure the rotation angle of the output shaft.

[0043] The position sensor may also include a potentiometer connected to the output shaft for detecting the absolute position of rotation; the magnetic encoder may be mounted at the vertical center of the output shaft and is not directly connected to the output shaft.

[0044] Specifically, the position sensor includes a magnetic encoder, which is mounted at the end of the output shaft of the brushless DC servo and connected to a microprocessor via a hardware IIC or SPI communication interface to form a position and speed feedback link for detecting the output shaft angle and speed of the brushless DC servo.

[0045] In some embodiments, the motor drive circuit and the current detection circuit are integrated into the motor drive chip.

[0046] Specifically, the motor drive circuit and the current detection circuit are integrated into the motor drive chip, achieving a high degree of integration of the drive chip.

[0047] In some embodiments, an external sensor interface electrically connected to the microprocessor is also included. The external sensor interface is an IIC interface or an SPI interface, used to connect a pressure sensor or a displacement sensor.

[0048] The external sensor interface is electrically connected to the sensor communication interface of the microprocessor 10. The external sensor can be a pressure sensor or a displacement sensor. In this embodiment, the control device, through the external sensor interface, has the capability to acquire and process sensor data at the servo motor end, providing extended external physical quantity feedback.

[0049] Specifically, the pressure / displacement sensor signal is directly sent to the servo motor's local microprocessor via the IIC / SPI interface, realizing local closed-loop control based on sensor-acquired signals, thus solving the problem in traditional control devices. The problem of long delays and low efficiency arises from the fact that external sensor data must first be uploaded to the host computer, and then the host computer calculates and issues new position commands.

[0050] The microprocessor 10 is used to perform feedback adjustment based on feedback signals obtained from the motor drive circuit, current detection circuit, position sensor interface, and external sensor interface, thereby realizing closed-loop control of the brushless DC motor at the servo end. In this embodiment, the feedback adjustment can be an existing feedback control algorithm, such as a PID algorithm.

[0051] In some embodiments, a power management module is further included. The input terminal of the power management module is used to connect to an external power supply, and the output terminal of the power management module is connected to the microprocessor, the motor drive circuit, the position sensor interface, the external sensor interface and the bus communication circuit for power supply.

[0052] The power management module may include a first-stage voltage regulator unit and a second-stage voltage regulator unit connected in sequence. The first-stage voltage regulator unit is used to convert the externally input 6-18V power supply to 5V power supply, and the second-stage voltage regulator unit is used to convert the 5V power supply to 3.3V power supply.

[0053] Specifically, the power management module directly supplies power to the microprocessor, motor drive circuit, position sensor interface, external sensor interface, and bus communication circuit, thereby providing a stable power supply to each component of the control device and ensuring the stable operation of the control device.

[0054] It should be noted that the microprocessor, power management module, motor drive circuit, and current detection circuit can be integrated onto a main control board measuring 21mm x 10mm.

[0055] In some embodiments, the microprocessor is connected to an external crystal oscillator.

[0056] The external crystal oscillator can be an external 48MHz passive crystal oscillator.

[0057] Specifically, the microprocessor is connected to an external crystal oscillator, which provides a stable and accurate master clock for the microprocessor, ensuring the timing reliability of CAN FD communication.

[0058] In one specific implementation, such as Figure 2 The diagram shown is another structural schematic of the control device for a brushless DC servo. The control device for a brushless DC servo includes a power management link, a CAN FD communication link, a servo output shaft angle detection link, a brushless DC motor drive and current detection link, and an external sensor detection link, where J1-J7 are all connectors.

[0059] The power management link is divided into two paths when the input power is 6~18V. One path directly supplies the motor drive circuit 20, and the other path sequentially passes through two LDO1 and LDO2 stages to convert the input power into 5V and 3.3V power branches. The 5V power branch powers the CAN FD chip, and the 3.3V power branch powers the magnetic encoder, external sensors, Hall sensor interface of the brushless DC motor, and microprocessor 10.

[0060] The CAN FD link consists of a microprocessor 10 that supports CAN FD communication, a CAN transceiver chip, and related peripheral circuits.

[0061] The motor drive circuit 20 and current detection circuit 30 constitute the drive and current detection link of the brushless DC servo motor. This link consists of a microprocessor, a motor drive chip, and related peripheral circuits. The motor drive chip includes six N-channel MOSFET drive circuits, three low-side current detection circuits, a sleep circuit, and a fault alarm circuit. The six N-channel MOSFET drive circuits are divided into three groups, with their outputs connected to three coils (A-phase, B-phase, and C-phase) inside the brushless DC motor 60 at 120-degree angles to each other. They are controlled by the control IO and timer IO connected to the microprocessor 10, and are energized sequentially using six different energizing methods to generate a composite magnetic field that drives the brushless DC motor 60. Different PWM duty cycles used during the drive correspond to different motor speeds. The analog signals output by the current detection circuits 30 connected to the three low-side terminals of phases A, B, and C are connected to the internal ADC of the microprocessor 10 for analog acquisition via external input pins. The acquired data is calculated by the microprocessor 10 to obtain the three-phase current values, which are then used for current loop control at the servo motor end.

[0062] The sleep circuit can reduce the current of the drive circuit to tens of microamps when the motor does not need to work. If undervoltage, overcurrent or thermal shutdown occurs during the operation of the drive circuit, an alarm signal will be generated by outputting a low level through the open drain of the nFAULT pin of the drive chip.

[0063] This utility model also provides a distributed servo motor system. Figure 3 A schematic diagram of an embodiment of the distributed servo system provided by this utility model is shown below. Figure 3 As shown, the distributed servo system includes: A host computer 100; control devices for at least two of the above-mentioned brushless DC servos, each of the control devices serving as an intelligent node 200; a shared bus communication link 300; the host computer 100 and all the intelligent nodes 200 are connected to the shared bus communication link 300.

[0064] Specifically, the host computer 100 and all intelligent nodes 200 are connected to a shared bus communication link 300. This shared bus communication link simultaneously connects the control devices of multiple brushless DC servos, replacing the traditional method where each servo requires an independent signal line (such as PWM or analog feedback lines). The number of system wiring harnesses changes from multiplying with the number of nodes to a fixed value, significantly reducing the complexity of system wiring.

[0065] In some embodiments, the shared bus communication link is a CAN FD bus.

[0066] Specifically, all servo nodes and the host computer only need to be connected through a shared CAN FD bus to achieve the exchange of all control and status data, realizing high-bandwidth, low-latency system-level communication and meeting the needs of multi-axis collaboration.

[0067] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A control device for a brushless DC servo motor, characterized in that, include: The microprocessor, a motor drive circuit, a current detection circuit, a position sensor interface, and a bus communication circuit, all electrically connected to the microprocessor; The input and output terminals of the motor drive circuit are electrically connected to the microprocessor and the brushless DC motor in the brushless DC servo motor, respectively. The current detection circuit is connected in series in the circuit between the motor drive circuit and the armature winding of the brushless DC motor, and the output terminal of the current detection circuit is connected to the microprocessor. The input terminal of the position sensor interface is connected to a position sensor mounted on the output shaft of the brushless DC servo motor, and the output terminal of the position sensor interface is connected to the microprocessor.

2. The control device for the brushless DC servo motor according to claim 1, characterized in that, The bus communication circuit is a CAN FD communication circuit, which includes a CAN FD transceiver chip connected to the microprocessor.

3. The control device for the brushless DC servo motor according to claim 1, characterized in that, The position sensor interface is a hardware SPI interface or a hardware IIC interface.

4. The control device for the brushless DC servo motor according to claim 3, characterized in that, The position sensor includes a magnetic encoder.

5. The control device for the brushless DC servo motor according to claim 1, characterized in that, The motor drive circuit and the current detection circuit are integrated into the motor drive chip.

6. The control device for the brushless DC servo motor according to claim 1, characterized in that, It also includes an external sensor interface electrically connected to the microprocessor, wherein the external sensor interface is an IIC interface or an SPI interface, for connecting a pressure sensor or a displacement sensor.

7. The control device for the brushless DC servo motor according to claim 6, characterized in that, It also includes a power management module, whose input terminal is used to connect to an external power source, and whose output terminal is connected to the microprocessor, the motor drive circuit, the position sensor interface, the external sensor interface and the bus communication circuit for power supply.

8. The control device for the brushless DC servo motor according to claim 1, characterized in that, The microprocessor is connected to an external crystal oscillator.

9. A distributed servo motor system, characterized in that, include: A host computer; At least two control devices for brushless DC servos as described in any one of claims 1 to 8, each of the control devices serving as an intelligent node; A shared bus communication link; The host computer and all the intelligent nodes are connected to the shared bus communication link.

10. The distributed servo system according to claim 9, characterized in that, The shared bus communication link is a CAN FD bus.

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