Robot joint motor driving circuit based on EtherCAT protocol

Abstract

The utility model provides a robot joint motor driving circuit based on an EtherCAT protocol. The robot joint motor driving circuit is suitable for a scene using a medium-sized servo motor as a joint motor. Comprising two paths of 100M Ethernet transceivers, an MCU integrated with an EtherCAT slave station controller, a DC-DC conversion circuit, a pre-drive circuit, an MOS power circuit, an analog quantity collector, an absolute value encoder and an incremental encoder. 48V direct current is respectively converted into 12V, 3.3 V and 2.5 V by a DC-DC conversion circuit, a PWM (Pulse Width Modulation) interface of an MCU (Microprogrammed Control Unit) of the integrated EtherCAT slave station controller is connected with a control end of a pre-drive circuit, an ADC (Analog to Digital Converter) interface is connected with an analog quantity acquisition unit, an SPI (Serial Peripheral Interface) interface is connected with an absolute value encoder, an SSC (Secure Socket Converter) interface is connected with an incremental encoder, and an MII (Media Independent Interface) interface is The output of the pre-drive circuit is connected with the control end of the MOS power circuit, and the output of the MOS power circuit controls the motor to work.

Description

Technical Field

[0001] This invention relates to the field of joint motor control, and more specifically to a robot joint motor drive circuit based on the EtherCAT protocol. Background Technology

[0002] Robotic systems play a vital role in modern life, not only enhancing industrial automation and production efficiency but also serving as key players in the medical, service, and home sectors. Within these systems, articulated motors are central. These motors drive the robot's various joints, ensuring the robot can execute complex motion paths and tasks, such as precise positioning, flexible manipulation, and high-speed dynamic response. However, driving articulated motors is not without challenges. They face multiple difficulties in achieving rapid dynamic response, precise position control, and efficient energy management. Especially when handling tasks with significant weight or resistance, the motors must provide sufficient torque to overcome these resistances, making this a crucial consideration in articulated motor actuation.

[0003] To address these challenges, the industry has introduced the EtherCAT protocol as a solution. EtherCAT, with its high performance and low latency, ensures real-time control and precise synchronization of articulated motors in robot systems. This protocol not only supports complex robot configurations but also provides flexible network topologies, enabling highly reliable system operation and effectively solving key issues such as real-time performance and synchronization in articulated motor drives. Furthermore, torque, a critical challenge in articulated motor drives, requires the motor to provide sufficient force when needed to ensure the robot can stably perform various tasks and actions.

[0004] Therefore, it is necessary to propose a joint motor drive circuit based on the EtherCAT protocol. Summary of the Invention

[0005] Based on the above-mentioned technical background problems, this invention provides a robot joint motor drive circuit based on the EtherCAT protocol, suitable for scenarios using medium-sized servo motors as joint motors. It achieves high-precision control of the joint motors by exchanging information and transmitting commands between the robot and the controller via the EtherCAT protocol. The circuit includes two 100M Ethernet transceivers, an MCU with an integrated EtherCAT slave controller, a DC-DC converter circuit, a pre-drive circuit, a MOS power circuit, an analog signal acquisition unit, an absolute encoder, and an incremental encoder. The DC-DC converter circuit converts 48V DC power to 12V, 3.3V, and 2.5V respectively, powering the pre-drive circuit, the MCU with the integrated EtherCAT slave controller, the analog signal acquisition unit, the absolute encoder, the incremental encoder, and the two 100M Ethernet transceivers. The PWM interface of the MCU with the integrated EtherCAT slave controller is connected to the control terminal of the pre-drive circuit, the ADC interface is connected to the analog signal acquisition unit, the SPI interface is connected to the absolute encoder, the SSC interface is connected to the incremental encoder, and the two MII interfaces are connected to the two 100M Ethernet transceivers. The output of the pre-drive circuit is connected to the control terminal of the MOS power circuit, and the output of the MOS power circuit controls the operation of the motor. The analog signal acquisition, absolute encoder, and incremental encoder acquire the operating conditions of the motor.

[0006] The two 100M Ethernet transceivers include a MAC signal terminal and an MDI signal terminal. One 100M Ethernet transceiver is the receiving end, with its MDI signal terminal connected to the host computer or master station, and its MAC signal terminal connected to the MII interface of the MCU integrated with the EtherCAT slave controller. This MAC signal terminal receives control commands and sends them to the MCU for parsing and execution. The other 100M Ethernet transceiver is the transmitting end, with its MDI signal terminal connected to the host computer, master station, or the next cascaded slave station, and its MAC signal terminal connected to the MII interface of the MCU integrated with the EtherCAT slave controller. This MAC signal terminal receives processed messages from the MCU and sends them back to the host computer, master station, or the next cascaded slave station.

[0007] The MCU integrating the EtherCAT slave controller is used to parse and execute control commands, specifically including MII, PWM, ADC, SPI, and SSC interfaces. The MII interface connects to the two Ethernet transceivers for receiving control commands and sending processed messages; the PWM interface connects to the pre-drive circuit for motor drive; the ADC interface connects to the analog acquisition unit for acquiring motor operating conditions; the SPI interface connects to the absolute encoder; and the SSC interface connects to the incremental encoder.

[0008] The DC-DC converter circuit converts DC power to the power supply levels required by various parts of the circuit. It includes three step-down circuits that convert 48V DC power to 12V, 3.3V, and 2.5V respectively, supplying power to the pre-drive circuit, the MCU with integrated EtherCAT slave controller, the absolute encoder, and the 100M Ethernet transceiver. The 48V to 12V circuit includes an asynchronous step-down regulator and its associated circuitry; the 12V to 3.3V circuit includes an asynchronous step-down regulator and its associated circuitry; and the 3.3V to 2.5V circuit includes a step-down chip and its associated circuitry. The DC-DC converter circuit also includes power indicator lights for the 12V and 3.3V voltages.

[0009] The pre-drive circuit includes a drive signal input terminal and a drive signal output terminal. The drive signal input terminal is connected to the PWM interface of the MCU of the integrated EtherCAT slave controller, and after passing through a three-way half-bridge gate driver, it is connected to the MOS power circuit through the drive signal output terminal.

[0010] The pre-drive circuit receives the drive control signal output from the MCU of the integrated EtherCAT slave controller and outputs it to the MOS power circuit. The pre-drive circuit is connected to a 12V power supply and includes three half-bridge gate drivers, which drive the A-phase (U-phase), B-phase (V-phase), and C-phase (W-phase) of the articulated motor, respectively. The MOS power circuit generates a three-phase AC power supply to drive the articulated motor based on the drive signal. The MOS power circuit is connected to a 48V power supply. The switching of MOSFETs Q1 and Q2 generates a voltage U to control the A-phase (U-phase) of the articulated motor; the switching of MOSFETs Q3 and Q4 generates a voltage V to control the B-phase (V-phase) of the articulated motor; and the switching of MOSFETs Q5 and Q6 generates a voltage W to control the C-phase (W-phase) of the articulated motor.

[0011] The analog signal acquisition is used to collect the operating conditions of the articulated motor and feed them back to the MCU of the integrated EtherCAT slave controller. This includes three-phase voltage acquisition, three-phase phase acquisition, bus voltage acquisition, motor temperature acquisition, and board temperature acquisition. The phase voltage acquisition is connected to the voltages of phases U, V, and W respectively, and after processing, outputs to the MCU of the integrated EtherCAT slave controller. The phase current acquisition is collected at the phase current acquisition point in the MOS power circuit, amplified by three operational amplifiers, and then output to the MCU of the integrated EtherCAT slave controller. The bus voltage acquisition is a 48V voltage that is processed and output to the MCU of the integrated EtherCAT slave controller. The board temperature acquisition outputs temperature information to the MCU of the integrated EtherCAT slave controller via a thermistor. The motor temperature acquisition is connected to the thermistor on the articulated motor and outputs temperature information to the MCU of the integrated EtherCAT slave controller.

[0012] The absolute encoder is used to measure the rotor position of the articulated motor and provide feedback on the motor's angular position, including a magnetic angle encoder and its associated circuitry. The absolute position of the magnetic field direction in the articulated motor is detected and encoded, and output to the MCU of the integrated EtherCAT slave controller via a four-wire interface.

[0013] The incremental encoder provides feedback on the relative position changes of the articulated motor by outputting a series of pulse signals, including a magnetic field angle sensor and its associated circuitry. The relative position of the magnetic field direction in the articulated motor is detected and encoded, and output to the MCU of the integrated EtherCAT slave controller via a three-wire interface.

[0014] The robot joint motor drive circuit based on the EtherCAT protocol described in this invention achieves high-precision control of the joint motors by using an MCU with an integrated EtherCAT slave controller for information exchange and command transmission between the robot and the controller. Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by means of embodiments of the invention.

[0015] To make the above description of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a circuit connection block diagram of the robot joint motor drive circuit based on the EtherCAT protocol described in this invention.

[0018] Figure 2 This is a connection block diagram of the DC-DC converter circuit in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention.

[0019] Figure 3 For the corresponding Figure 2 The circuit schematic diagram of the DC-DC converter circuit connection block diagram;

[0020] Figure 4This is a circuit diagram of the pre-drive circuit and MOS power circuit in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention.

[0021] Figure 5 This is a circuit diagram of analog signal acquisition in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention.

[0022] Figure 6 This is a circuit diagram of the absolute encoder and incremental encoder in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention.

[0023] Figure 7 This is a circuit diagram of two 100M Ethernet transceivers in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention.

[0024] Figure 8 This is a circuit schematic diagram of the MCU that integrates an EtherCAT slave controller in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention.

[0025] Number in the picture:

[0026] 101, 102: 100M Ethernet transceiver (for receiving, for sending); 103: Buffer circuit; 104: Indicator light;

[0027] 20: MCU integrating EtherCAT slave controller; 201: MCU; 202: Oscillator circuit; 203: Reset button;

[0028] 30: DC-DC converter circuit; 301: 48V to 12V step-down circuit; 302: 12V to 3.3V step-down circuit; 303: 3.3V to 2.5V step-down circuit;

[0029] 40: Pre-drive circuit; 50: MOS power circuit;

[0030] 60: Analog signal acquisition; 601: Phase voltage acquisition; 602: Phase current acquisition; 603: Bus voltage acquisition; 6041: Onboard temperature acquisition; 6042: Motor temperature acquisition;

[0031] 70: Absolute encoder; 80: Incremental encoder;

[0032] U1: Asynchronous buck regulator; U2: Asynchronous buck regulator; U3: Buck chip U3; U4, U5, U6: Half-bridge gate driver; U7, U8, U9: Operational amplifier; U10: Magnetic angle encoder; U11: Magnetic field angle sensor; U12, U14: 100M Ethernet transceiver; U13, U15: Network port transformer; U16: Buffer; Q1~Q6: MOSFETs. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0034] Please see Figure 1 This is a circuit connection block diagram of the robot joint motor drive circuit based on the EtherCAT protocol described in this invention. It includes two 100M Ethernet transceivers 101 and 102, an MCU 20 integrating an EtherCAT slave controller, a DC-DC converter 30, a pre-drive circuit 40, a MOS power circuit 50, an analog signal acquisition unit 60, an absolute encoder 70, and an incremental encoder 80. The DC-DC converter 30 converts 48V DC power to 12V, 3.3V, and 2.5V respectively, supplying power to the pre-drive circuit 40, the MCU 20 integrating the EtherCAT slave controller, the analog signal acquisition unit 60, the absolute encoder 70, the incremental encoder 80, and the 100M Ethernet transceivers 101 and 102. The PWM interface of the MCU20, which integrates the EtherCAT slave controller, is connected to the control terminal of the pre-drive circuit 40. Its ADC interface is connected to the analog signal acquisition unit 60, its SPI interface to the absolute encoder 70, its SSC interface to the incremental encoder 80, and its two MII interfaces to two 100M Ethernet transceivers 101 and 102. The output of the pre-drive circuit 40 is connected to the control terminal of the MOS power circuit 50, and the output of the MOS power circuit 50 controls the motor's operation.

[0035] Please see Figure 2The diagram shows the connection block diagram of the DC-DC conversion circuit in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention. It includes a circuit 301 that converts 48V DC to 12V, a circuit 302 that converts 12V to 3.3V, and a circuit 303 that converts 3.3V to 2.5V. Circuit 301 supplies power to the pre-drive circuit 40. Circuit 302 supplies power to the MCU 20 that integrates the EtherCAT slave controller, the operational amplifier circuit in the analog acquisition 60, the position sensor in the absolute encoder 70, the speed sensor in the incremental encoder 80, and the 100M Ethernet transceivers 101 and 102. Circuit 303 performs level conversion of the clock signal and provides it to the 100M Ethernet transceivers 101 and 102.

[0036] Please see Figure 3 , for the corresponding Figure 2 The circuit schematic diagram of the DC-DC converter circuit connection block diagram includes circuits 301, 302, 303, and 304. Circuit 301 includes an asynchronous buck regulator U1 and its supporting circuitry, which reduces 48V DC to 12V; circuit 302 includes an asynchronous buck regulator U2 and its supporting circuitry, which reduces 12V DC to 3.3V; circuit 303 includes a buck chip U3 and its supporting circuitry, which reduces 3.3V to 2.5V; circuit 304 includes power indicator lights for 12V and 3.3V voltages.

[0037] Please see Figure 4 This is a circuit diagram of the pre-drive circuit and MOS power circuit in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention, including a pre-drive circuit 40 and a MOS power circuit 50. The pre-drive circuit 40 is connected to a 12V power supply and includes half-bridge gate drivers U4, U5, and U6, which drive phases A, B, and C of the joint motor, respectively. The MOS power circuit 50 is connected to a 48V power supply. The switching of MOSFETs Q1 and Q2 generates voltage U to control phase A of the joint motor, the switching of MOSFETs Q3 and Q4 generates voltage V to control phase B of the joint motor, and the switching of MOSFETs Q5 and Q6 generates voltage W to control phase C of the joint motor. IPHASEU, IPHASEV, and IPHASEW are the phase current acquisition points of the motor in the analog acquisition unit 60.

[0038] Please see Figure 5 This is a circuit schematic diagram of the analog signal acquisition in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention. It includes phase voltage acquisition 601, phase current acquisition 602, bus voltage acquisition 603, board temperature acquisition 6041, and motor temperature acquisition 6042. Phase voltage acquisition 601 is connected to the voltages of phases U, V, and W respectively, and after processing, outputs to the MCU through FDSU, FDS V, and FDS W. Phase current acquisition 602... Figure 4 The phase current acquisition points IPHASEU, IPHASEV, and IPHASEW in the MOS power circuit 50 are acquired, amplified by operational amplifiers U7, U8, and U9, and then output to the MCU. The bus voltage acquisition point 603 acquires 48V voltage, processes it, and outputs it to the MCU. The on-board temperature acquisition point 6041 outputs temperature information to the MCU via a thermistor. The motor temperature acquisition point 6042 connects to a thermistor on the motor (only the pads are shown in the diagram; the thermistor itself is not depicted) and outputs the temperature information to the MCU.

[0039] Please see Figure 6 This is a circuit diagram of the absolute encoder and incremental encoder in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention, including an absolute encoder 70 and an incremental encoder 80. The absolute encoder 70 includes a magnetic angle encoder U10 and its associated circuitry, which performs absolute position detection and encoding of the magnetic field direction in the joint motor, and outputs the result to the MCU via a four-wire interface. The incremental encoder 80 includes a magnetic field angle sensor U11 and its associated circuitry, which performs relative position detection and encoding of the magnetic field direction in the joint motor, and outputs the result to the MCU via a three-wire interface.

[0040] Please see Figure 7 This is a circuit diagram of two 100M Ethernet transceivers in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention. It includes a receiving circuit 101, a transmitting circuit 102, a buffer circuit 103, and an indicator light 104. The receiving circuit 101 includes a 100M Ethernet transceiver U12 and its associated circuitry, and a network port transformer U14. It connects to a host computer or master station via interface P1 to receive control signals transmitted via Ethernet. After isolation by the network port transformer U14, the signals are connected to the MDI signal terminal of U12, and then connected to the MCU via the MAC signal terminal. The transmitting circuit 102 includes a 100M Ethernet transceiver U13 and its associated circuitry, and a network port transformer U15. Signals generated by the MCU are connected to U13 via the MAC signal terminal, and after isolation by the network port transformer U15, they are connected to a host computer, master station, or a cascaded slave station via interface P2 to transmit control signals transmitted via Ethernet. The buffer circuit 103 includes buffer U16 and its associated circuitry, which enhances the driving capability of the RESET signal generated by the MCU so that the RESET pins of U12 and U13 can be connected simultaneously. Indicator light 104 indicates the operating status and fault status of 101 and 102.

[0041] Please see Figure 8This is a circuit schematic of the MCU integrating an EtherCAT slave controller in the robot joint motor drive circuit based on the EtherCAT protocol described in this invention. It includes MCU201, an oscillation circuit 202, and a reset button 203. Among all the pins used by MCU201, the MII interfaces are P7.0~P7.11, P8.0~P8.11, and P9.0~P9.11, which connect to two Ethernet transceivers for receiving control commands and sending processed messages; the PWM interface is P0.0~P0.5, which connects to the pre-drive circuit for motor drive; the ADC interfaces are P14.0~P14.3, P14.12, P15.2, P15.4, P15.12, and P15.15, which acquire the phase voltage and phase current of the joint motor, bus voltage, board temperature, and motor temperature; the SPI interface is P6.1~P6.5, which connects to an absolute encoder; and the SSC interfaces are P3.0, P3.5, and P3.6, which connect to an incremental encoder. The oscillation circuit 202 includes a low-frequency oscillation circuit Y1 and a high-frequency oscillation circuit Y2. Y1 generates a real-time clock for the MCU, and Y2 generates a high-frequency clock for the MCU. The reset button 203 is used to reset the circuit during testing or debugging.

[0042] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A robot joint motor drive circuit based on the EtherCAT protocol, characterized in that, The system includes two 100M Ethernet transceivers, an MCU with an integrated EtherCAT slave controller, a DC-DC converter, a pre-drive circuit, a MOS power circuit, an analog signal acquisition unit, an absolute encoder, and an incremental encoder. The DC-DC converter transforms 48V DC power into 12V, 3.3V, and 2.5V respectively, powering the pre-drive circuit, the MCU with the integrated EtherCAT slave controller, the analog signal acquisition unit, the absolute encoder, the incremental encoder, and the two 100M Ethernet transceivers. The MCU with the integrated EtherCAT slave controller has its PWM interface connected to the control terminal of the pre-drive circuit, its ADC interface connected to the analog signal acquisition unit, its SPI interface connected to the absolute encoder, its SSC interface connected to the incremental encoder, and two MII interfaces connected to the two 100M Ethernet transceivers. The output of the pre-drive circuit is connected to the control terminal of the MOS power circuit, and the output of the MOS power circuit controls the motor's operation. The analog signal acquisition unit, the absolute encoder, and the incremental encoder acquire the motor's operating conditions. The two 100M Ethernet transceivers include a MAC signal terminal and an MDI signal terminal. One 100M Ethernet transceiver is a receiver, with its MDI signal terminal connected to the host computer or master station, and its MAC signal terminal connected to the MII interface of the MCU integrated with the EtherCAT slave controller. It is used to receive control commands and send the control commands to the MCU for parsing and execution. The other 100M Ethernet transceiver is a transmitter, with its MDI signal terminal connected to the host computer, master station, or the next cascaded slave station, and its MAC signal terminal connected to the MII interface of the MCU integrated with the EtherCAT slave controller. It receives processed messages from the MCU and sends them back to the host computer, master station, or the next cascaded slave station. The MCU with integrated EtherCAT slave controller is used to parse and execute control commands, including MII interface, PWM interface, ADC interface, SPI interface and SSC interface; the MII interface is connected to the two 100M Ethernet transceivers to receive control commands and send processed messages, the PWM interface is connected to the pre-drive circuit for motor drive, the ADC interface is connected to the analog signal acquisition for acquiring motor operating conditions, the SPI interface is connected to the absolute encoder, and the SSC interface is connected to the incremental encoder. The DC-DC converter circuit includes three step-down circuits that convert 48V DC power to 12V, 3.3V, and 2.5V respectively, supplying power to the pre-drive circuit, the MCU with integrated EtherCAT slave controller, the absolute encoder, and the 100M Ethernet transceiver; the 48V to 12V circuit includes an asynchronous step-down regulator and its supporting circuitry; the 12V to 3.3V circuit includes an asynchronous step-down regulator and its supporting circuitry; the 3.3V to 2.5V circuit includes a step-down chip and its supporting circuitry; and power indicator lights for 12V and 3.3V voltages are also included. The pre-drive circuit includes a drive signal input terminal and a drive signal output terminal. The drive signal input terminal is connected to the PWM interface of the MCU of the integrated EtherCAT slave controller, and after passing through a three-way half-bridge gate driver, it is connected to the MOS power circuit through the drive signal output terminal. The MOS power circuit generates three-phase AC power to drive the joint motor according to the drive signal and is connected to a 48V power supply. The analog signal acquisition is used to collect the operating conditions of the joint motor and feed them back to the MCU of the integrated EtherCAT slave controller, including three-phase voltage acquisition, three-phase phase acquisition, bus voltage acquisition, motor temperature acquisition, and single-board temperature acquisition; The absolute encoder includes a magnetic angle encoder and its supporting circuit, which performs absolute position detection and encoding of the magnetic field direction in the articulated motor, and outputs it to the MCU of the integrated EtherCAT slave controller through a four-wire interface; The incremental encoder includes a magnetic field angle sensor and its supporting circuit, which performs relative position detection and encoding of the magnetic field direction in the articulated motor, and outputs it to the MCU of the integrated EtherCAT slave controller through a three-wire interface.

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