Self-locking brushless motor system

Abstract

The invention discloses a self-locking brushless motor system, and the system collects the position information of a torque motor through a first encoder, collects the rotation speed, direction information and position information of a servo motor through a second encoder and a position detection sensor, and detects the displacement of a motion assembly driven by the torque motor and the servo motor in real time. The linear motion and the rotary motion of the motion assembly between two limit positions in a plane can be driven, and meanwhile electric self-locking can be achieved at a designated position.

Description

Technical Field

[0001] This application relates to the technical field of motor control, and particularly to a self-locking brushless motor system. Background Art

[0002] In the moving components of some relatively precise instruments, it is impossible to meet some specific requirements by only driving the components with one motor. For example, in addition to moving between two extreme positions in a plane, rotation is also required. Further, electric self-locking is required at specific positions. Therefore, it is urgent for those skilled in the art to propose a self-locking brushless motor system to achieve the above functions. Summary of the Invention

[0003] This application provides a self-locking brushless motor system, which realizes the linear motion and rotational motion of the moving components between two extreme positions in a plane, and can achieve electric self-locking at a specified position.

[0004] In view of this, this application provides a self-locking brushless motor system, and the system includes:

[0005] A control unit, a torque motor drive unit, a torque motor, and a first encoder;

[0006] The control unit outputs three-way PWM pulses to the torque motor through the torque motor drive unit;

[0007] The first encoder collects and feeds back the position information of the torque motor to the control unit;

[0008] It further includes: a servo motor, a servo motor drive unit, a second encoder, and a position detection sensor;

[0009] The control unit outputs two-way complementary PWM pulses to the servo motor through the servo motor drive unit;

[0010] The second encoder collects and feeds back the rotation speed and direction information of the servo motor to the control unit;

[0011] The position detection sensor collects and feeds back the position information of the servo motor to the control unit.

[0012] Optionally, it further includes: a servo motor encoder signal processing circuit;

[0013] The servo motor encoder signal processing circuit acquires the quadrature pulse signal transmitted by the second encoder, and after resistor voltage division limiting and the AND gate with Schmitt input characteristics, inputs it to the control unit.

[0014] Optionally, it further includes: a torque motor phase current detection circuit;

[0015] The torque motor phase current detection circuit collects the three-phase positive and negative currents of the torque motor and inputs them to the control unit.

[0016] Optionally, it further includes: an input power supply filtering circuit;

[0017] The input power supply filtering circuit supplies power to the torque motor drive unit and the servo motor drive unit respectively.

[0018] Optionally, it further includes: a 3.3V voltage stabilizing circuit;

[0019] The 3.3V voltage stabilizing circuit stabilizes the 3VDC input from the input power supply filtering circuit to 3.3V and supplies power to the control unit and the level conversion circuit.

[0020] Optionally, it further includes: a level conversion circuit;

[0021] The level conversion circuit performs level conversion between the input power supply filtering circuit and the control unit, and between the first encoder and the control unit.

[0022] Optionally, it further includes: an RS422 isolation drive circuit;

[0023] The RS422 isolation drive circuit is connected to the level conversion circuit.

[0024] Optionally, it further includes:

[0025] A thermistor and a temperature acquisition circuit;

[0026] The temperature acquisition circuit applies a bias voltage to the thermistor and inputs it to the control unit through an amplification sub-circuit;

[0027] The temperature acquisition circuit is powered by the input power supply filtering circuit.

[0028] Optionally, it further includes: an input voltage sampling circuit;

[0029] The input end of the input voltage sampling circuit is connected to the input power supply filtering circuit, and the output end is connected to the control unit.

[0030] From the above technical solutions, it can be seen that the embodiments of the present application have the following advantages:

[0031] In this application, a self-locking brushless motor system is provided. The position information of the torque motor is collected by the first encoder, and the rotation speed, direction information, and position information of the servo motor are collected by the second encoder and the position detection sensor. The displacement of the moving components driven by the torque motor and the servo motor is detected in real time, enabling linear motion and rotational motion between two extreme positions of the moving components in a plane, and electric self-locking can be achieved at a specified position. Description of the Drawings

[0032] Figure 1 It is the system framework diagram of a self-locking brushless motor system in an embodiment of this application;

[0033] Figure 2 It is the MCU circuit diagram of the control unit;

[0034] Figure 3 It is the circuit diagram of the torque motor drive unit;

[0035] Figure 4 It is the first encoder pulse diagram;

[0036] Figure 5 It is the circuit diagram of the servo motor drive unit;

[0037] Figure 6 It is the second encoder pulse diagram;

[0038] Figure 7 It is the circuit diagram of the servo motor encoder signal processing circuit;

[0039] Figure 8 It is the circuit diagram of the torque motor phase current detection circuit

[0040] Figure 9 It is the circuit diagram of the input power filter circuit;

[0041] Figure 10 It is the circuit diagram of the 3.3V voltage stabilization circuit;

[0042] Figure 11 It is the circuit diagram of the level conversion circuit;

[0043] Figure 12 It is the circuit diagram of the RS422 isolation drive circuit;

[0044] [[ID=1...]Figure 13 It is the circuit diagram of the temperature acquisition circuit;

[0045] Figure 14 It is the circuit diagram of the input voltage sampling circuit. Detailed Implementation Manner

[0046] To enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0047] For ease of understanding, please refer to Figure 1 , Figure 1 which is the system framework diagram of a self-locking brushless motor system in the embodiments of this application. As Figure 1 shown, specifically:

[0048] Control unit 01, torque motor drive unit 02, torque motor 03, and first encoder 04;

[0049] The control unit 01 outputs three-way PWM pulses to the torque motor 03 through the torque motor drive unit 02;

[0050] The first encoder 04 collects and feeds back the position information of the torque motor 03 to the control unit 01.

[0051] It should be noted that, as Figure 2 shown, Figure 2 is the MCU circuit diagram of the control unit. Among them, U14 is the chip, Y1 is the active crystal oscillator, and R8 and C8 form the power-on reset circuit. The MCU detects the input power supply voltage, motor temperature, phase current of the torque motor, encoder signals of the two motors, and limit signals of the servo motor. The MCU communicates with the upper computer and the lower computer through RS422, receives commands from the upper computer, and then performs real-time control on the two motors respectively according to the collected signals, and reports the status of the motors and the controller to the upper computer at the same time.

[0052] The driver collects the operation data and stores it in the FLASH memory inside the control chip for the upper computer to call.

[0053] The MCU circuit has a JTAG interface for external debugging for users to perform secondary development. Users can connect the JTAG through the corresponding signal ports on the connector of the driver.

[0054] The MCU circuit reserves a JTAG interface for debugging, and the software can also be upgraded online through RS422.

[0055] The working voltage of the MCU is 3.3V; the working temperature range is: -40°C to +85°C; the main frequency is 168MHz; 194KB SRAM; 1MB Flash; 51 GPIO ports; 2 UART ports.

[0056] As Figure 3 shown, Figure 3 Figure 1 is the circuit diagram of the torque motor drive unit, and an integrated dedicated drive chip is selected for the motor drive. Figure 3 In Figure 1, PWM1 - PWM3 are three - phase PWM pulses from the MCU, and EN1 - EN3 are corresponding enable signals. RESET1, SLEEP1, and FAULT1 are the reset signal input, sleep signal input, and fault status signal output of U1 respectively.

[0057] motor - A to motor - C are three - phase motor drive signals after power amplification. R24 - R26 are motor phase current sampling resistors.

[0058] U6 is selected as AT8313 from Zhongke Micro Corporation, with a working voltage of 8V - 35V; the working temperature range: - 40°C to + 125°C; the peak output current is 3A; the over - current protection point is 3A - 5A, and the normal - temperature output resistance is 0.45Ω; the body diode voltage drop is at most 1.5V; the dead - time is 50 - 300ns; three - phase half - bridge drive.

[0059] As Figure 4 shown, Figure 4 Figure 2 is the first encoder pulse diagram. The first encoder uses the magnetoelectric principle to detect the rotational mechanical angle of the motor, and outputs A, B, Z signals and PWM pulses. The resolution of A and B signals is 1024 lines. When the A pulse leads by 90°, it is a forward rotation, and when the B pulse leads by 90°, it is a reverse rotation. The width of the PWM pulse is proportional to the rotational mechanical angle. The corresponding relationship is as Figure 4 shown. In this design, the PWM frame frequency is 971.1Hz. It is an absolute encoding within 360°. The motor reduction ratio is 10:1, and the angle detection resolution is 360 / 4096 / 10 = 0.0088°. It meets the requirement that the control error is less than 0.1°.

[0060] Furthermore, it also includes: servo motor 05, servo motor drive unit 06, second encoder 07, and position detection sensor 08;

[0061] The control unit 01 outputs two complementary PWM pulses to the servo motor 05 through the servo motor drive unit 06;

[0062] The second encoder 07 collects and feeds back the rotational speed and direction information of the servo motor 05 to the control unit 01;

[0063] The position detection sensor 08 collects and feeds back the position information of the servo motor 05 to the control unit 01.

[0064] It should be noted that, as Figure 5 shown, Figure 5It is the circuit diagram of the servo motor drive unit. An integrated dedicated drive chip is selected for the servo motor drive. Figure 5 Among them, PWM1-BDC and PWM2-BDC are the control PWM pulses from the MCU respectively, and M2+ and M2- are the motor drive pulses after power amplification. R63 sets the sampling voltage proportional to the motor current. After comparing with the protection point voltage set by R2 and R3, the overcurrent protection function is realized. U1 is the HWD8870 of Chengdu Huawei Company, with a working voltage of 8V to 40V; the working temperature range is -55°C to +125°C; the peak output current is 2.5A; the output resistance at normal temperature is 0.6Ω; the maximum forward voltage drop of the body diode is 1.5V; the dead time is 50 to 300ns. It meets the requirement of the input voltage range of 22VDC to 29VDC.

[0065] As Figure 6 shown, Figure 6 It is the second encoder pulse diagram. The encoder uses the magnetoelectric principle. To prevent misoperation, the quadrature encoding pulses start to be output 16ms after power-on, with a resolution of 1024 lines, as shown in the following figure. When the A pulse leads by 90°, it is a forward rotation, and when the B pulse leads by 90°, it is a reverse rotation. The motor reduction ratio is 10:1, so the angle detection resolution is 360 / 1024 / 10 = 0.035°. It meets the requirement that the control error is less than 0.1°.

[0066] Furthermore, it also includes: the servo motor encoder signal processing circuit 09;

[0067] The servo motor encoder signal processing circuit 09 obtains the quadrature pulse signal transmitted by the second encoder 07, and after resistor voltage division and amplitude limiting and the AND gate with Schmitt input characteristics, it is input to the control unit 01.

[0068] It should be noted that as Figure 7 shown, Figure 7 It is the circuit diagram of the servo motor encoder signal processing circuit. The quadrature pulse signals QEPA and QEPB from the second encoder, after resistor voltage division and amplitude limiting, enter the AND gate with Schmitt input characteristics and then are sent to the GPIO port of the MCU. By analyzing the frequency and phase of the quadrature pulses, the speed and rotation direction information of the motor can be obtained.

[0069] Furthermore, it also includes: the torque motor phase current detection circuit 10;

[0070] The torque motor phase current detection circuit 10 collects the three-phase positive and negative currents of the torque motor 03 and inputs them to the control unit 01.

[0071] It should be noted that as Figure 8 shown, Figure 8 It is the circuit diagram of the torque motor phase current detection circuit. Taking the A-phase current detection as an example, as Figure 8As shown, the voltage across the phase-A current sampling resistor R2 is filtered by R31, R28, and C53 to remove spikes, amplified by the amplifier circuit composed of U9B and peripheral resistors, and then sent to the A / D port of the MCU. Since positive and negative currents are collected, after the input of the amplifier is biased by a 1.65V reference voltage, the output voltage becomes a positive voltage.

[0072] Further, it also includes: an input power supply filtering circuit 11;

[0073] The input power supply filtering circuit 11 supplies power to the torque motor drive unit 02 and the servo motor drive unit 06 respectively.

[0074] It should be noted that, as Figure 9 shown, Figure 9 is the circuit diagram of the input power supply filtering circuit. According to the motor technical indicators required by the technology, the peak current of the torque motor during stable operation does not exceed 5A, and the peak current of the servo motor during stable operation does not exceed 3A.

[0075] As Figure 9 shown, the input 28VDC is filtered by the differential-mode filter circuit composed of the differential-mode inductor L2 and peripheral capacitors to remove the noise of the input source, and at the same time, it also suppresses the influence of the noise generated by the subsequent circuit on the input source. The low on-state voltage Schottky diodes D1~D3 isolate the two motor power supply circuits to prevent mutual interference.

[0076] The input 5VDC auxiliary power supply is filtered by the filter circuit composed of L4, C59, and C60 and then supplies power to the control circuit.

[0077] The capacitors selected for the motor power supply circuit are from the 4326 factory, and their withstand voltages are not less than 50V. The Schottky diodes are selected from the 873 factory's (G) 1N5809, with a reverse breakdown voltage of 100V, a forward average current of 6A, and both the voltage and current are not lower than the secondary derating. The capacitors selected for the auxiliary power supply circuit are from the 4326 factory, and their withstand voltages are not less than 10V, and the withstand voltage is not lower than the secondary derating

[0078] Further, it also includes: a 3.3V voltage regulation circuit 12;

[0079] The 3.3V voltage regulation circuit 12 regulates the input 3VDC from the input power supply filtering circuit 11 to 3.3V and supplies power to the control unit 01 and the level conversion circuit 13.

[0080] It should be noted that, as Figure 10 shown, Figure 10 is the circuit diagram of the 3.3V voltage regulation circuit. The 3.3V voltage regulation circuit uses an LDO to regulate the input 5VDC to 3.3V to supply power to the MCU and its peripheral circuits. U8 is selected from the (G) JW117 of the Jibansuo, with a maximum input voltage of 40V and an output current of not less than 0.5A.

[0081] Further, it further includes: a level conversion circuit 13;

[0082] The level conversion circuit 13 performs level conversion between the input power supply filtering circuit 11 and the control unit 01, and between the first encoder 04 and the control unit 01.

[0083] It should be noted that, as Figure 11 shown, Figure 11 is the circuit diagram of the level conversion circuit. The level conversion is completed by the level conversion chip U5 with direction adaptability, and level conversion is performed between the external interface circuit powered by 5V and the circuit powered by 3.3V such as the MCU. U5 performs level conversion on the drive signals of two paths of RS422, the transmission enable signal, and the encoder signal of the torque motor.

[0084] Further, it further includes: an RS422 isolation drive circuit 14;

[0085] The RS422 isolation drive circuit 14 is connected to the level conversion circuit 13.

[0086] It should be noted that, as Figure 12 shown, Figure 12 is the circuit diagram of the RS422 isolation drive circuit. The driver has two paths of RS422 interfaces, namely path A and path B. Taking the first path of RS422 communication as an example, as Figure 12 shown. The RS422 isolation drive is completed by the chip U4. U4 internally integrates an isolated DC / DC conversion, and converts the input +5VD into an isolated 5V voltage (VCC5_422A) for use by the bus interface.

[0087] Further, it further includes:

[0088] a thermistor RT1 and a temperature acquisition circuit 16;

[0089] The temperature acquisition circuit 16 applies a bias voltage to the thermistor RT1, and inputs it to the control unit 01 through an amplification sub-circuit;

[0090] The temperature acquisition circuit 16 is powered by the input power supply filtering circuit 11.

[0091] It should be noted that, as Figure 13 shown, Figure 13 is the circuit diagram of the temperature acquisition circuit. The U13 generates a reference voltage of 2V to apply a bias voltage to the thermistor RT1. The maximum input voltage of U13 is 7V, and the recommended maximum operating voltage is not higher than 5.5V, meeting the power supply range of the technical requirements. After the reference voltage is divided by the thermistor and R60, a voltage that changes monotonically with temperature is obtained. After being driven by U12A, it is amplified by the amplification circuit composed of U12B and its peripheral circuits, and then sent to the A / D port of the MCU.

[0092] Further, it further includes: an input voltage sampling circuit 17;

[0093] The input end of the input voltage sampling circuit 17 is connected to the input power supply filtering circuit 11, and the output end is connected to the control unit 01.

[0094] It should be noted that, as Figure 14 shown, Figure 14 is the circuit diagram of the input voltage sampling circuit. After the input voltage is divided by resistors, it is driven by the follower of U11A and then sent to the A / D port of the MCU.

[0095] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A self-locking brushless motor system, characterized in that, Including: A control unit, a torque motor drive unit, a torque motor, and a first encoder; The control unit outputs three-way PWM pulses to the torque motor through the torque motor drive unit; The first encoder collects and feeds back the position information of the torque motor to the control unit; It further includes: a servo motor, a servo motor drive unit, a second encoder, and a position detection sensor; The control unit outputs two-way complementary PWM pulses to the servo motor through the servo motor drive unit; The second encoder collects and feeds back the rotational speed and direction information of the servo motor to the control unit; The position detection sensor collects and feeds back the position information of the servo motor to the control unit.

2. The self-locking brushless motor system according to claim 1, wherein It further includes: A servo motor encoder signal processing circuit; The servo motor encoder signal processing circuit obtains the quadrature pulse signal transmitted by the second encoder, and after resistor voltage division limiting and an AND gate with Schmitt input characteristics, inputs it to the control unit.

3. The self-locking brushless motor system according to claim 1, wherein, It further includes: A torque motor phase current detection circuit; The torque motor phase current detection circuit collects the three-phase positive and negative currents of the torque motor and inputs them to the control unit.

4. The self-locking brushless motor system according to claim 3, wherein It further includes: An input power supply filtering circuit; The input power supply filtering circuit supplies power to the torque motor drive unit and the servo motor drive unit respectively.

5. The self-locking brushless motor system according to claim 4, wherein, It further includes: A 3.3V voltage stabilizing circuit; The 3.3V voltage stabilizing circuit stabilizes the 3VDC input by the input power supply filtering circuit to 3.3V and supplies power to the control unit and the level conversion circuit.

6. The self-locking brushless motor system according to claim 5, characterized in that, It further includes: A level conversion circuit; The level conversion circuit performs level conversion between the input power supply filtering circuit and the control unit and between the first encoder and the control unit.

7. The self-locking brushless motor system according to claim 6, wherein, It further includes: An RS422 isolation drive circuit; The RS422 isolation drive circuit is connected to the level conversion circuit.

8. The self-locking brushless motor system according to claim 7, wherein, It further includes: A thermistor and a temperature acquisition circuit; The temperature acquisition circuit applies a bias voltage to the thermistor and inputs it to the control unit through an amplification sub-circuit; The temperature acquisition circuit is powered by the input power supply filtering circuit.

9. The self-locking brushless motor system according to claim 8, wherein, It further includes: an input voltage sampling circuit; The input end of the input voltage sampling circuit is connected to the input power supply filtering circuit, and the output end is connected to the control unit.

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