Flexible feeding control circuit of voice coil motor and flexible feeding equipment

Abstract

The invention relates to the field of automation control, in particular to a circuit for voice coil motor control and flexible feeding control. The flexible feeding control circuit of the voice coil motor comprises a CPU control circuit, a high-power H half-bridge drive circuit, a current limiting circuit, a current detection circuit, a TCP communication circuit, an RS232 communication circuit, an RS485 communication circuit, a voltage monitoring circuit, a wide voltage stabilization power supply circuit, an IO interface circuit and a data storage circuit. The control circuit is simple and clear, the structure is more optimized and reasonable, the connection and cooperation of all functional units ensure the reliability of the control circuit on one hand, greatly simplify the design of the circuit on the other hand, have extremely low plate space occupation consumption, and greatly reduce the cost of the equipment circuit on the other hand; meanwhile, interference of electromagnetic reflection and mechanical vibration of the voice coil motor on control circuit pulses can be solved, and accurate control over the motion stroke and speed of the voice coil motor is improved.

Description

Technical Field

[0001] The invention relates to the field of automation control, and in particular to a circuit for controlling a voice coil motor and flexible feeding control. Background Art

[0002] The voice coil motor is a special form of DC linear motor that does not require mechanical parts such as screws or gears. It has the advantages of high frequency response, high acceleration, and small size. To better reflect these advantages, its motion control system should have the characteristics of fast response, no overshoot, and strong robustness. In order to solve the contradiction between rapidity and overshoot, not only a rigorous program algorithm is required, but also a set of high-precision and high-reliability control circuits are the rigid prerequisites for realizing the fast linear and high-precision motion of the voice coil motor.

[0003] The voice coil motor is used in the flexible feeding system. Its movements are very flexible. The workpiece in the material box can move forward, backward, left, right, and flip over smoothly and with high precision. Its drive control system uses two methods: one is the control method of using a servo motor, which is like a big horse pulling a small cart. It is costly, has redundant circuits, and has electromagnetic interference; the other is the control circuit of an ordinary linear motor, which cannot improve its movement accuracy and speed. Moreover, the electromagnetic reflection and mechanical vibration of the voice coil motor interfere with the control circuit pulse, which easily affects the accuracy of its movement and is difficult to solve. Summary of the invention

[0004] In view of the defects or shortcomings of the prior art, the present invention aims to solve the above-mentioned problems and further designs a flexible feeding control circuit and a flexible feeding device for a voice coil motor. The control circuit is simple and clear, which greatly reduces the cost of the device circuit. It can not only resist the interference of electromagnetic reflection and mechanical vibration of the voice coil motor on the pulse signal, but also realize the fast linear response and high precision of the voice coil motor.

[0005] In a first aspect, the present application discloses a flexible feeding control circuit of a voice coil motor, comprising a high-power H half-bridge driving circuit, a CPU control circuit and a wide voltage regulated power supply circuit; wherein the high-power H half-bridge driving circuit is connected to control the voice coil motor; the CPU control circuit is connected to and controls the high-power H half-bridge driving circuit, so that the controlled high-power H half-bridge driving circuit drives the voice coil motor to generate a vibration torque with a corresponding amplitude, frequency and phase; the wide voltage regulated power supply circuit is connected to the CPU control circuit, and is used to access external input power and output corresponding DC power;

[0006] The high-power H half-bridge drive circuit includes a motor drive module, a current detection module, a signal isolation module, a current limiting module, and a model interaction interface with a CPU.

[0007] Furthermore, the CPU control circuit, as the central processor of the control system, applies the STM32F103ZET6 single-chip microcomputer, which has an IO interface circuit for data exchange with the PLC, a TCP communication interface for data interaction with the PC host computer, an RS485 communication interface for data interaction with the touch screen, an RS232 communication interface for system settings of the CPU, and a data storage circuit for storing data.

[0008] Furthermore, the wide voltage regulated power supply circuit provides a stable power supply for the CPU control circuit, the high-power H half-bridge drive circuit and the voice coil motor, etc., to ensure the normal operation of the system, and includes a voltage input module, a voltage monitoring module and a wide voltage conversion module; wherein, the voltage input module realizes efficient and stable output through a P-channel field effect transistor and a diode; the voltage monitoring module is used to monitor the working voltage at each point of the circuit to ensure the normal operation of the circuit, and includes a single-channel high-gain frequency compensation operational amplifier; the wide voltage conversion module uses a gallium nitride field effect transistor, and when the P-channel field effect transistor of the voltage input module is turned on, the wide voltage conversion module converts the obtained voltage into a weak voltage.

[0009] Furthermore, the high-power H half-bridge driving circuit receives the PWM signal of the single-chip microcomputer through a model interaction interface with the CPU.

[0010] Furthermore, the high-power H-half-bridge drive circuit isolates the interference source voice coil motor and the part of the CPU control circuit that is susceptible to interference through the signal isolation module, so that the CPU and the voice coil drive circuit maintain signal connection without direct electrical connection, thereby cutting off the influence of EMI interference caused by the voice coil motor on the PWM wave. Otherwise, PWM is prone to burrs, affecting the accuracy of the voice coil motor movement.

[0011] Furthermore, the motor drive module of the high-power H half-bridge drive circuit has a brake pin, which turns on the drive circuit when the level is high and turns off the drive circuit when the level is low; it includes a P-channel high-side MOSFET and an N-channel low-side MOSFET; the gate of the MOSFET field effect tube is connected in series with a resistor and a diode in parallel to delay the opening of the field effect tube and quickly discharge the gate-source capacitance voltage to ensure that the switch tube can be quickly turned off. The application of the P-channel high-side switch does not require a charge pump and can minimize EMI electromagnetic interference. The system can quickly return to the original balance position after being disturbed by the outside world, which improves the anti-interference ability of the circuit. The drive circuit with logic level input realizes the acceleration and deceleration of the vibration of the voice coil motor and the rapid control of the compression, ejection and emergency stop of the motor.

[0012] Furthermore, the high-power H half-bridge drive circuit collects the current passing through the voice coil motor in real time through a current detection module, and the current detection module is connected to the IS end of the motor drive module to monitor the current passing through the upper back MOSFET tube; the current detection module has an external resistor R93 connected to the SR end of the motor drive part, and the on and off time of the MOSFET tube is adjusted by adjusting the size of the SR foot external resistor R93, which has an anti-electromagnetic interference function.

[0013] Furthermore, the high-power H half-bridge drive circuit controls the current of the drive circuit through a current limiting module. When the current passing through the voice coil motor coil is too high, the switch transistor in the circuit is triggered, the PWM signal is directly blocked, the power tubes of the power circuit are turned off, and an overcurrent indication is given.

[0014] On the second aspect, the present application discloses a flexible feeding device, comprising four voice coil motors, which are respectively arranged on the four supporting feet of the device, and material bins are mounted on the four supporting feet for holding the materials to be supplied; the special feature is that a circuit board with the above-mentioned flexible feeding control circuit is arranged in the middle of the device.

[0015] The flexible feeding control circuit of a voice coil motor described in the present invention has a more optimized and reasonable structure. The connection and coordination of various functional units ensure the reliability of the control circuit on the one hand, and greatly simplify the design of the circuit on the other hand. It has extremely low board space consumption and can solve the interference of the electromagnetic reflection and mechanical vibration of the voice coil motor on the control circuit pulse, thereby improving the precise control of the movement stroke and speed of the voice coil motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the flexible feeding equipment involved in the present invention;

[0017] Figure 2 It is a schematic diagram showing the structure and working principle of the control system of the present invention;

[0018] Figure 3 It is the overall circuit principle diagram of the present invention;

[0019] Figure 4 It is a schematic diagram of a high-power H half-bridge driving circuit of the present invention;

[0020] Figure 5 It is a schematic diagram of a wide voltage stabilized power supply circuit of the present invention;

[0021] Figure 6 It is a schematic diagram of the RS232 communication circuit of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0023] Embodiment 1

[0024] like Figure 1 As shown, a schematic diagram of the flexible feeding equipment involved in the present invention is given. This flexible feeding equipment mainly includes four voice coil motors (voice coil motor A, voice coil motor B, voice coil motor C, voice coil motor D), which are respectively located at the four supporting legs of the rectangular device; the middle of the device is the control circuit board E described in this invention; a material bin F is set on the four supporting legs for holding the materials to be supplied.

[0025] like Figure 2 As shown, a flexible feeding control circuit of a voice coil motor is provided, the control circuit includes a CPU control circuit, a high-power H half-bridge drive circuit and a wide voltage regulated power supply circuit, wherein the CPU control circuit has a TCP communication interface, an RS485 communication interface, an RS232 communication interface, an IO interface circuit and a data storage circuit; a current detection module is provided between the CPU control circuit and the high-power H half-bridge drive circuit, and a current limiting module is provided between the high-power H half-bridge drive circuit and the voice coil motor.

[0026] like Figure 3 As shown, the overall circuit schematic diagram of the present invention is given, and Figure 1 The control system corresponds one to one. Figure 3 Among them, module 3-8 is the CPU control circuit, module 3-4 is a four-way high-power H half-bridge drive circuit, module 3-3 is a TCP communication interface, module 3-2 is an RS232 communication interface, module 3-1 is an RS485 communication interface, module 3-5 is a wide voltage regulated power supply circuit, module 3-6 is an IO interface circuit, and module 3-7 is a data storage circuit.

[0027] The specific structure of each circuit module is described in detail below:

[0028] Module 3-8, the CPU control circuit of the present invention, as the central processor of the control system, uses the STM32F103ZET6 single-chip microcomputer, which mainly completes system initialization, position control algorithm, PWM wave generation, A / D acquisition control, current loop calculation, Ethernet communication, motor limit and overcurrent protection, and data exchange with PLC and host computer. The PWM dedicated module of the ARM chip of the CPU circuit generates PWM waves with dead zones, enhances the switching speed, reduces the switching loss, and can accurately control the frequency and duty cycle of the PWM signal. It generates a set of PWM waves required for voice coil motor control, and controls the vibration stroke and vibration speed of a single voice coil motor by changing the duty cycle and frequency of the PWM signal. A total of four PWM waves are generated, and the start and stop time of the voice coil motor are adjusted by adjusting the initial phase and the end phase of each PWM wave, so as to control the different vibrations of the four voice coil motors in four directions to control the flexible movement of the product in the tray. The analysis of the communication protocol is also implemented in the CPU. The communication interface converts the information into electrical signals. Then the CPU will analyze and process the received signals, respond, and send out interactive signals. The CPU and the host computer interact with each other through the TCP network communication interface using the TCP / IP protocol to control data. The CPU and the touch screen interact with each other through the RS485 communication interface using the ModbusRTU protocol to control data. In addition, the system parameters in the CPU can be set through the RS232 communication interface. The CPU and PLC exchange data through the IO interface circuit.

[0029] The TCP communication interface described in Module 3-3 is a network interface circuit designed based on the W5500 embedded Ethernet control chip. It has better compatibility with various switches / routers and stronger adaptability. It also provides a network wake-up mode (WOL) and a power-down mode while providing low-voltage power supply. It will not generate heat even when working for a long time, thus avoiding overheating problems and greatly reducing the energy consumption of the system.

[0030] The RS485 communication interface described in Module 3-1 is an RS485 automatic transceiver circuit with a data transmission rate of up to 10Mbps. It only requires two communication lines and can transmit data between two or more devices. This data transmission connection is a half-duplex communication method. At a certain moment, a device can only send or receive data, using balanced transmission and differential reception. Therefore, it has the ability to suppress common-mode interference and the communication distance can reach thousands of meters.

[0031] The IO interface circuit described in Module 3-6 uses AC / DC optocoupler IC, does not distinguish between positive and negative input voltages, and has a bidirectional LED as its core component. It is not limited by signal polarity and can achieve circuit isolation between input and output within a wider voltage range, achieve comprehensive signal capture and conversion, and effectively avoid current and voltage interference and transmission, thereby improving system reliability and stability. The solid-state relay with a flexible and compact package (SOP4) and extremely low off-state leakage current is easy to integrate on the circuit board, and minimizes power consumption in standby or off state, improving energy efficiency.

[0032] The data storage circuit described in Module 3-7 is a wide voltage, low power consumption, 4kbit electrically erasable programmable read-only memory that saves data after power failure and can be called out at the next run. It can be written 1 million times and data can be stored for 100 years.

[0033] like Figure 4 As shown, a schematic diagram of a high-power H half-bridge driving circuit of the present invention is given, that is, Figure 3 Module 3-4 in the circuit. This driving circuit includes a motor driving module 4-1, a current detection module 4-2, a signal isolation module 4-3, a current limiting module 4-4, and a model interaction interface 4-5 with the CPU. The output drive voltage of this high-power H half-bridge driving circuit can reach 40V, the drive current can reach 55A, and the drive frequency can reach 25KHZ, which can drive the high-power voice coil motor to move quickly.

[0034] The high-power H half-bridge drive circuit is used to receive the PWM signal from the single-chip microcomputer and convert it into a voltage signal that can drive the voice coil motor to operate. The high-frequency PWM can be realized through active freewheeling, thereby realizing precise control of the movement stroke and speed of the voice coil motor. The drive circuit receives the PWM signal from the single-chip microcomputer through the model interaction interface 4-5 with the CPU, and then sends it to the signal isolation module 4-3; the interference source voice coil motor and the part of the CPU control circuit that is susceptible to interference are isolated through the signal isolation module 4-3, so that the CPU and the voice coil drive circuit maintain signal contact without direct electrical contact, thereby cutting off the influence of EMI interference caused by the voice coil motor on the PWM wave, otherwise the PWM is prone to burrs, affecting the accuracy of the voice coil motor movement.

[0035] The PWM wave signal isolated by the signal isolation module 4-3 is sent to the motor drive module 4-1 and sent to the signal logic circuit of the motor drive module through the IN port for processing. INH is the brake pin of the drive circuit. When INH is low, the drive circuit is in the off state. When the INH pin inputs a high level, the output voltage of the OUT terminal is determined by the PWM duty cycle input at the IN terminal. The P-type tube Q17 in the drive circuit is turned on when the gate is low and turned off when the gate is high; the N-type tube Q18 is turned on when the gate is high and turned off when the gate is low. Therefore, when the PWM wave duty cycle of the IN input is greater than a certain value, the internal circuit outputs a low level to turn on the upper back P-type MOSFET tube Q17. At this time, by adjusting the input duty cycle, the output voltage of the 0UT terminal is adjusted, thereby driving the voice coil motor to operate. When the input duty cycle is 0, the drive circuit outputs a high level to turn on the lower back N-type MOSFET tube Q18. At this time, there is no PWM wave output at the 0UT terminal, and the voice coil motor stops operating.

[0036] Q17 and Q18, the gates are connected in series with resistors R100 and R101 respectively, so that the positive rise time of the input signal is delayed due to the charge accumulated on the gate of the field effect tube; the input resistors R100 and R101 are connected in parallel with diodes D6 and D7 respectively, and the diodes are reverse biased, which delays the turning on of the field effect tube, avoids the breakdown of the field effect tube caused by the simultaneous turning on of the two power tubes and plays a current limiting role to reduce circuit losses; at the moment of shutdown, the drive circuit can provide a path with the lowest possible impedance for the MOSFET tube gate-source capacitance voltage to be quickly discharged, ensuring that the switch tube can be quickly turned off, that is, the diode is forward biased and shunted with the resistor, so that the gate-source junction capacitance is quickly discharged, protecting the internal weak current circuit from being interfered by the strong current of the motor.

[0037] The motor drive module 4-1 is connected to the current detection module 4-2 through the IS terminal to monitor the current passing through the upper back MOSFET tube in real time (i.e. the current current of the motor). The size of the external resistor R93 of the SR pin can adjust the on and off time of the MOSFET tube, which has the function of preventing electromagnetic interference.

[0038] like Figure 5 As shown, a schematic diagram of a wide voltage regulated power supply circuit of the present invention is given, that is, Figure 3 Module 3-5 in the figure. 5-1 is the voltage input part. The voltage enters the circuit through the fuse F1 and then reaches the P-channel field effect transistor shown in Q21. Q21 has low on-resistance and large current carrying capacity, can withstand high voltage, and is easy to saturate and fully open, and can switch very quickly between saturation areas. At the same time, diode ZD1 is used for voltage stabilization. Q21 and ZD1 jointly realize the high-efficiency and stable output of the power switch of the high-power voice coil motor, which improves the reliability of the circuit.

[0039] 5-3 is a voltage monitoring module, where U2 is a single-channel high-gain frequency compensation operational amplifier. This circuit is intended to monitor whether the operating voltage at each point in the circuit is in a relatively stable normal value state, so as to determine whether the circuit is operating normally or what kind of fault exists.

[0040] When Q21 is turned on, the voltage is sent to the wide voltage conversion module 5-3 and converted into a weak voltage to power the CPU and its peripheral circuits. This circuit is designed with a high-performance GaN field effect transistor U3, which has low resistance, high-speed switching and high voltage resistance characteristics, a wide input voltage range of 4.5V to 36V, and an adjustable output voltage range of 0.8V to 36V, which can provide up to 1.2A of continuous output current. U3 has an internal soft start function and an adjustable soft start function, and supports fault protection functions such as thermal shutdown, short circuit protection and cycle-by-cycle current limiting.

[0041] like Figure 6 As shown, a schematic diagram of the RS232 communication circuit of the present invention is given. The RS232 communication circuit of the present invention is a USB to 3-wire RS232 serial port circuit interface, that is, Figure 3 The module 3-2 in the system can realize the change and setting of system parameters. The RS232 communication circuit of the present invention comprises a model interaction interface 6-1 with the CPU, a power-off automatic reset module 6-2, a communication conversion chip 6-3, and a transient voltage suppressor 6-4.

[0042] In order to protect high-speed data lines from damage by electrostatic discharge (ESD), the communication receiving and transmitting signals first pass through the 6-4 transient voltage suppressor U40, and then connect to the 6-3 communication conversion chip U6 to be converted into a communication code that can be parsed by the CPU, and then sent to the CPU for processing through the 6-1 interactive interface; when the system parameters are set through this circuit and need to be reset, the 6-2 power-off automatic reset circuit part can realize power-off reset without human intervention.

Claims

1. A flexible feeding control circuit for a voice coil motor, characterized in that: It includes a high-power H half-bridge drive circuit, a CPU control circuit and a wide voltage regulated power supply circuit; wherein the high-power H half-bridge drive circuit is connected to control the voice coil motor; the CPU control circuit is connected to and controls the high-power H half-bridge drive circuit, so that the controlled high-power H half-bridge drive circuit drives the voice coil motor to generate a vibration torque with a corresponding amplitude, frequency and phase; the wide voltage regulated power supply circuit is connected to the CPU control circuit, and is used to access external input power and output corresponding DC power; The high-power H half-bridge drive circuit includes a motor drive module, a current detection module, a signal isolation module, a current limiting module, and a model interaction interface with a CPU.

2. A flexible feeding control circuit for a voice coil motor as claimed in claim 1, characterized in that: The CPU control circuit, as the central processor of the control system, applies the STM32F103ZET6 single-chip microcomputer, which has an IO interface circuit for data exchange with the PLC, a TCP communication interface for data interaction with the PC host computer, an RS485 communication interface for data interaction with the touch screen, an RS232 communication interface for system settings of the CPU, and a data storage circuit for storing data.

3. A flexible feeding control circuit for a voice coil motor as claimed in claim 1, characterized in that: The wide voltage regulated power supply circuit includes a voltage input module, a voltage monitoring module and a wide voltage conversion module; wherein the voltage input module realizes efficient and stable output through a P-channel field effect tube and a diode; the voltage monitoring module is used to monitor the working voltage of each point of the circuit to ensure the normal operation of the circuit, and it includes a single-channel high-gain frequency compensation operational amplifier; the wide voltage conversion module uses a gallium nitride field effect transistor, and when the P-channel field effect tube of the voltage input module is turned on, the wide voltage conversion module converts the obtained voltage into a weak voltage.

4. A flexible feeding control circuit for a voice coil motor as claimed in claim 1, characterized in that: The high-power H half-bridge driving circuit receives the PWM signal of the single-chip microcomputer through the model interaction interface with the CPU.

5. The flexible feeding control circuit of a voice coil motor as claimed in claim 1, characterized in that: The high-power H half-bridge drive circuit isolates the interference source voice coil motor and the part of the CPU control circuit that is susceptible to interference through the signal isolation module, so that the CPU and the voice coil drive circuit maintain signal connection without direct electrical connection, thereby cutting off the influence of EMI interference caused by the voice coil motor on the PWM wave.

6. A flexible feeding control circuit for a voice coil motor as claimed in claim 1, characterized in that: The motor drive module of the high-power H half-bridge drive circuit has a brake pin, which turns on the drive circuit when the level is high and turns off the drive circuit when the level is low.

7. A flexible feeding control circuit for a voice coil motor as claimed in claim 1, characterized in that: The motor drive module of the high-power H half-bridge drive circuit includes a P-channel high-side MOSFET and an N-channel low-side MOSFET; the gate of the MOSFET field-effect tube is respectively connected in series with a resistor and in parallel with a diode to delay the opening of the field-effect tube and quickly discharge the gate-source capacitance voltage to ensure that the switch tube can be quickly turned off.

8. The flexible feeding control circuit of a voice coil motor as claimed in claim 1, characterized in that: The high-power H half-bridge drive circuit collects the current passing through the voice coil motor in real time through a current detection module. The current detection module is connected to the IS end of the motor drive module to monitor the current passing through the upper back MOSFET tube; the current detection module has an external resistor R93 connected to the SR end of the motor drive part. The on and off time of the MOSFET tube is adjusted by adjusting the size of the external resistor R93 of the SR foot, and has an anti-electromagnetic interference function.

9. A flexible feeding control circuit for a voice coil motor as claimed in claim 4, characterized in that: The high-power H half-bridge drive circuit controls the current of the drive circuit through a current limiting module. When the current passing through the voice coil motor coil is too high, the switch transistor in the circuit is triggered, the PWM signal is directly blocked, the power tubes of the power circuit are turned off, and an overcurrent indication is given.

10. A flexible feeding device, comprising four voice coil motors, which are respectively arranged on four supporting legs of the device, and a material bin is set on the four supporting legs for containing the materials to be supplied; characterized in that: A circuit board having the flexible feeding control circuit according to any one of claims 1 to 9 is arranged in the middle of the device.

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