Robot joint power chip and driving method thereof

Abstract

The invention discloses a robot joint power chip and a driving method thereof. The problems that an existing robot joint module is high in design complexity, large in size and high in cost are mainly solved. The chip comprises an FOC, a torque regulation and control module, and an LDO circuit, a Manchester encoding and decoding circuit, a current sampling circuit and a driving circuit which are connected with the FOC and the torque regulation and control module. Wherein the Manchester encoding and decoding circuit is connected to a main controller of a robot through a communication interface, the LDO circuit is further connected with the Manchester encoding and decoding circuit and the driving circuit, and the current sampling circuit and the driving circuit are connected with a power tube array of a robot joint module. Data communication between the main controller of the robot joint module and the joint module is real-time, the transmission rate is higher, the anti-interference performance is good, meanwhile, the size of the robot joint module is greatly reduced, cost is reduced, loss is reduced, heat is reduced, and reliability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial intelligence control, and more specifically, to a robot joint power chip and a driving method thereof. Background Art

[0002] In recent years, the technology of embodied robots has developed rapidly, promoting the rapid commercialization of robots. With the continuous development of embodied robot technology, people have seen the hope of robots entering thousands of households. However, people are still working hard to achieve more anthropomorphic and lower-cost robots. To enable robots to perform anthropomorphic actions, robots are usually designed with dozens of degrees of freedom, and each degree of freedom is achieved by joint rotation. Currently, each joint rotation is completed by motor drive. Since most of the motors used on robots are DC brushless motors, the motors described in this article refer to DC brushless motors, but also include 3-phase drive motors such as permanent magnet AC motors. To accurately and flexibly control the actions of robots, the joint control of robots requires precise control of the rotational speed, angle, and torque of the motors. To avoid rough and abrupt robot actions, it is often necessary to appropriately and accurately control the torque of motor drive. Therefore, it is necessary to accurately measure and control the torque of motor rotation.

[0003] The prior art, as Figure 1 shown, all follow the existing power circuit structure of robot joint modules. It has a CAN interface circuit, an MCU main control circuit, a drive circuit, a power transistor array, a current sampling and amplification circuit, a brushless DC motor, a reducer, and corresponding sensors. The core function of the robot joint module is to accurately drive the rotation of the brushless DC motor M1, reduce the rotation speed through the reducer X1, and increase the rotational torque at the same time. To enable the main controller to accurately control the output torque, an encoder sensor or a torque sensor is usually installed on the brushless DC motor and the reducer to measure the output torque. The magnitude of the output torque is calculated by the angle of rotation of the motor rotor and the angle of rotation of the rotating shaft after the reducer, or the torque output on the reducer is directly transmitted back through the torque sensor. The brushless DC motor has 3 sets of coils, corresponding to 3 drive ports which are U, V, and W respectively, and is called 3-phase drive. The 3-phase drive of the motor is driven by a power transistor array. 6 power transistor arrays are connected in series in pairs to form 3 drive units, which are respectively connected to the 3-phase drive ends U, V, and W of the motor to drive the motor coils. As Figure 1The drain of the power transistor N1 is connected to the power supply VCC, the source is connected to the drain of the power transistor N2 to obtain the intermediate node output, which is connected to the U terminal of the motor. The source of the power transistor N2 is connected to the current sampling resistor RH1, and the other end of the sampling resistor is connected to GND. The gates of the power transistors N1 and N2 are both connected to the output of the drive circuit. The connection methods of the power transistors N3 and N4 are the same as those of N1 and N2, and the intermediate node output is connected to the V terminal of the motor. The difference in the connection method of the power transistors N5 and N6 is that there is no sampling resistor. Therefore, the source of N6 is directly connected to GND, and the intermediate node output is connected to the W terminal of the motor. Since the current loop control of the motor requires sampling of the two-phase drive current, the sources of the power N2 and N4 are respectively connected in series with the current sampling resistors RH1 and RH2. The current for driving the motor will be very large, usually requiring dozens of amperes of current. Therefore, the internal resistance of the power transistor is usually small, such as 4 mΩ, and the resistance value of the sampling resistor is also small, such as 1 mΩ. Even though the resistance value of the sampling resistor is small, its proportion relative to the internal resistance of the power transistor is relatively large, and the power consumption corresponding to dozens of amperes of working current is also relatively large. Therefore, the requirements for package heat dissipation are high. To ensure the current sampling accuracy, the resistance value accuracy of the resistor also needs to be relatively high, such as 1%. Therefore, the sampling resistor is required to have a small resistance value, good heat dissipation, and high accuracy. Such sampling resistors usually have a high price. Moreover, the sampling resistor connected in series under the power transistor also brings a large amount of additional power consumption. If the power transistor uses a GaN device, the voltage of the sampling resistor will also affect the gate-source voltage VGS of the GaN power transistor, thereby affecting the conduction performance of the GaN device. Since the resistance value of the sampling resistor is small, the voltage generated by the drive current is also small. An operational amplifier circuit needs to be added to amplify the voltage signal representing the current information of the sampling resistor. The amplified signal is sent to the MCU for analog-to-digital conversion. Therefore, the scheme of using a sampling resistor to sample the drive current brings many negative impacts and increases the cost. The power transistor array requires a corresponding drive circuit to drive the gate voltage switch of the power transistor. The drive circuit receives 3 control signals from the MCU and outputs 6 gate control signals corresponding to the gate signals g1-g6 of the power transistors N1-N6. The power circuit of the robot joint module uses an MCU (microcontroller) as the main controller. The CAN interface chip receives CAN bus data and commands and sends them to the MCU, and the MCU also controls the CAN interface chip to send data to the host. The MCU receives the encoded 1 information and encoded 2 or torque information returned by the structure of the motor M1 and the reducer X1, receives the two-phase current sampling signals in the three-phase drive of the motor, and also receives various sensor information such as temperature and pressure sensor information. The MCU outputs 3 motor control signals to the drive circuit according to the received commands and data, and drives the motor to rotate through the drive circuit outputting three-phase coil drive signals. The MCU judges whether the motor rotates according to the commanded requirements through the feedback sensor signals and current information, realizing the closed-loop control of the motor. The power circuit of the robot joint module also requires DCDC (direct current to direct current) and LDO (low dropout regulator) power management circuits.The power supply voltage VCC of the drive motor is usually relatively high, reaching dozens of volts or even more than one hundred volts. The drive voltage of the power transistor is different from the supply voltage of other circuits. For example, the drive voltage for MOS transistors (metal oxide semiconductor field effect transistors) is usually 12V, the drive voltage for GaN is usually 6 - 7V, and the power supply voltage of the MCU is usually 3.3V. Therefore, it is necessary to use a DCDC to step down the VCC voltage to 12V or 6V, and then use an LDO to step down the output voltage of the DCDC to 3.3V.

[0004] The CAN bus is widely used in automobiles and is responsible for the communication between various sensors and the main controller. The CAN bus has been widely applied and verified in automobiles. It can safely and reliably transmit data at high speed with only two wires, and the data transmission rate can reach 1MHz. In the prior art, most robot joint modules use the mature CAN bus to communicate with the main controller. However, when the communication method with a bus structure is applied to robots, it has both advantages and disadvantages. The advantages are that the solution is mature, with good versatility and compatibility, and the main controller only needs 2 data lines to communicate with multiple joint modules and sensors, resulting in fewer wiring harnesses and simpler wiring. However, the bus structure determines that it can only perform half-duplex data communication, and only one joint can send or receive data from the main controller at the same time. However, the application scenarios of robots are different from those of automobiles. Robots often have multiple joints running simultaneously. The main controller needs to issue control instructions to multiple joint modules at the same time, and there may also be a situation where the joint module uploads data to the main controller. If the CAN bus is used on the robot to be responsible for the communication between the main controller and multiple joints, then the priority of data transmission must be set first, which will cause some data to be sent later, bringing unpredictable delays to the robot joint control. This usually makes it difficult to handle the limb coordination of the robot during high-speed movement.

[0005] In robots, most brushless DC motors adopt the FOC (Field Oriented Control) control strategy. The FOC control strategy decomposes the stator current into two independent components: the excitation current and the torque current, and realizes the precise and independent adjustment of the motor flux and torque through current control. FOC motor control has the advantages of precise torque control, fast dynamic response, high efficiency, and low noise. Precise torque control and fast dynamic response are particularly important in the control of robot joint rotation.

[0006] In the prior art, torque sensors have begun to be installed at the reducer end to directly feedback the torque information at the output end for motor torque control. However, installing torque sensors has problems such as high cost, complex structure, and large volume. And they all have disadvantages. For example, non-contact torque sensors require a separate battery for power supply, and strain gauge torque sensors have poor accuracy and need to be calibrated. So people have studied solutions without torque sensors. Currently, the relatively popular one is the dual encoder scheme, such as Figure 1As shown, the torque magnitude is calculated by returning the high-precision encoded information 2 from the reducer end and the encoded information 1 from the motor end. As shown in patents CN109500837A, CN119501924A, and CN112008763A. It can be known from the research of the prior art that the calculation of torque by the dual-encoding method still requires relatively complex operations and calibrations, and is greatly affected by whether the reducer is a rigid structure or a flexible structure. Especially for flexible structure reducers, the error part needs to be calibrated, and as the flexible material ages, the torque detection will also have the problem of increasing errors. Both the torque sensor and the dual-encoder scheme rely on the feedback signal at the output end of the reducer. High-precision encoders and torque sensors are both costly, and on the joint structure, the lead wire at the joint output end needs to return to the motor control port, increasing the design difficulty of the structure. Most of the prior art uses the method of hollow joints to guide the wire, increasing the cost.

[0007] From Figure 1 The structure shows that the existing robot joint module has a complex circuit. Each circuit of the CAN interface circuit, MCU main control circuit, drive circuit, current sampling and amplification circuit, and power management circuit needs to be implemented by a chip circuit system. Therefore, the existing robot joint module has a large size and a complex circuit, and it is difficult to reduce the cost.

[0008] At the same time, the existing robot joint module circuit also has the risk of easy burnout of the power transistor array. The coil of the motor has an inductance effect, resulting in a reverse voltage, and also has a transformer characteristic, resulting in an induced voltage. The existing power transistor array drive cannot detect the U, V, and W at the motor drive end. When the drive power transistor is turned on under abnormal conditions, a large current is likely to burn out the power transistor. Summary of the Invention

[0009] The purpose of the present invention is to provide a robot joint power chip and its driving method, mainly solving the problems of high complexity in the design of existing robot joint modules, large size of joint modules, and high cost of joint modules.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows: A robot joint power chip includes an FOC and torque regulation module, as well as an LDO circuit, Manchester encoding and decoding circuit, current sampling circuit, and drive circuit that are all connected to the FOC and torque regulation module; among them, the Manchester encoding and decoding circuit is connected to the main controller of the robot through a communication interface, the LDO circuit is also connected to the Manchester encoding and decoding circuit and the drive circuit, the current sampling circuit and the drive circuit are connected to the power transistor array of the robot joint module, and FOC is field-oriented control.

[0011] Further, in the present invention, the current sampling circuit includes a control transistor Nm1 with its gate connected to the FOC and torque regulation module, an operational amplifier U1 with its positive input terminal Vp connected to the source of the control transistor Nm1, an overcurrent detection circuit connected to the source of the control transistor Nm1, a control transistor Nm2 with its gate connected to the output of the operational amplifier U1, a current-to-voltage and calibration circuit connected to the drain of the control transistor Nm2, an anomaly detection circuit connected to the drain of the control transistor Nm1, a resistor R1 and a capacitor C1 with one end connected to the drain of the control transistor Nm1, and a voltage stabilization circuit Z1 with one end connected to the drain of the control transistor Nm1 and the other end grounded; wherein, the other end of the capacitor C1 is grounded, the negative input terminal Vn of the operational amplifier U1, the other end of the resistor R1, and the source of the control transistor Nm2 are connected to the power transistor array of the robot joint module; the anomaly detection circuit, the overcurrent detection circuit, and the current-to-voltage and calibration circuit are all connected to the FOC and torque regulation module.

[0012] Further, in the present invention, the FOC and torque regulation module integrates a PID loop controller, and the FOC control has three loop controls: a current loop, a position loop, and a speed loop; wherein, the current loop obtains the current information of the coils of the motor of the robot joint module through two-phase current sampling, and after the current is converted and PID operation is performed, the voltage control signal of each coil of the motor at the next moment is obtained; the position loop and the speed loop use the encoding information of the motor to obtain the angular position and speed data of the motor of the robot joint module respectively, and after PID loop operation, the voltage control signal for controlling the rotation angle position and speed of the rotor of the motor M1 at the next moment is obtained.

[0013] Based on the above robot joint power chip, the present invention also provides a driving method for a motor of a robot joint module, including the following steps: S1, receiving the data on the data line through the communication interface of the Manchester encoding and decoding circuit, decoding it, and obtaining the command and data information transmitted by the main controller of the robot joint module; S2, the FOC and torque regulation module receives the decoded information of the Manchester encoding and decoding circuit, and obtains the target angular position, speed, and torque information for the motor to rotate; S3, the FOC and torque regulation module uploads the target angular position, speed, and torque information to the Manchester encoding and decoding circuit in real time, and the Manchester encoding and decoding circuit encodes it and sends the data to the main controller through the sending data line of the communication interface; S4, the FOC and torque regulation module samples the operating information of the motor of the robot joint module, converts the operating information into voltage control information, and then outputs a high-frequency PWM pulse duty cycle through operation to control the power transistor array of the robot joint module; wherein, the operating information is current information or encoding information; At S5, the average voltage output by the power transistor array is applied to the coil of the motor of the robot joint module to generate a corresponding current, and the current generates a torque to drive the rotor of the robot joint module motor to rotate.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) By integrating FOC control, torque regulation module, LDO power management, Manchester encoding and decoding, and current sampling circuit on a single chip, the present invention replaces the traditional discrete MCU, CAN interface chip and peripheral circuits, significantly reducing the circuit board area and the number of components. At the same time, a current sampling circuit without a sampling resistor (realizing current sampling through a sampling tube proportional to the power transistor) is adopted, avoiding the high cost and additional power consumption problems of traditional large-current sampling resistors, especially suitable for the GaN power transistor scenario, solving the interference problem of the sampling resistor voltage on the gate-source electrode, and improving the system reliability and energy efficiency.

[0015] (2) The present invention replaces the traditional CAN bus with a Manchester encoding and decoding circuit, and realizes point-to-point full-duplex communication between the main controller and the joint module through an independent communication interface, avoiding the priority scheduling delay caused by bus competition. At the same time, the FOC uploads the target angle, speed and torque information to the main controller in real time, and combines the efficient data transmission characteristics of Manchester encoding to ensure the real-time synchronization of commands and feedback signals during multi-joint coordinated motion, meeting the requirements of high-speed dynamic response of the robot and overcoming the problem of unpredictable timing of multi-joint concurrent control under the traditional bus architecture.

[0016] (3) The FOC control in the present invention integrates the three closed-loop PID controls of the current loop, position loop and speed loop. By fusing the two-phase current sampling and encoded information, the motor driving torque is directly calculated without an external torque sensor or a dual-encoder structure, simplifying the wiring complexity at the reducer end and reducing the hardware cost. At the same time, the current sampling circuit is built-in with overcurrent detection, abnormal detection and voltage stabilization circuit Z1, which real-time monitors the working state of the power transistor array, and quickly cuts off the fault path (such as turning off through Nm1) when the driving end voltage is abnormal or the current changes suddenly, avoiding the burning of the power transistor, especially suitable for protecting against reverse voltage shock in high-inductance load scenarios, and significantly improving the system robustness. Description of the Drawings

[0017] Figure 1 It is the circuit structure of the existing robot joint power module.

[0018] Figure 2 Schematic diagram of the robot joint power chip and module circuit structure of the present invention.

[0019] Figure 3 Schematic diagram of the current sampling circuit of the present invention. Detailed Embodiments

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. The implementation manners of the present invention include but are not limited to the following embodiments.

[0021] Embodiment 1 As Figure 2 shown, a robot joint power chip disclosed by the present invention includes an FOC and a torque regulation module, as well as an LDO circuit, a Manchester encoding and decoding circuit, a current sampling circuit, and a driving circuit that are all connected to the FOC and the torque regulation module; wherein, the Manchester encoding and decoding circuit is connected to the main controller of the robot through a communication interface, and the LDO circuit is also connected to the Manchester encoding and decoding circuit and the driving circuit. The current sampling circuit and the driving circuit are connected to the power transistor array of the robot joint module, and FOC is field-oriented control. Among them, the communication interface includes a receiving data line and a transmitting data line, and the other end of the communication interface is connected to the main controller to realize one-to-one real-time data communication between the main controller and the joint module, greatly reducing the delay. The present invention uses Manchester encoding with excellent anti-interference ability to transmit information in a single line, realizing the real-time full-duplex data transceiver function with the main controller. The Manchester encoding and decoding circuit receives the data on the receiving data line of the communication interface, decodes it to obtain the commands and data information transmitted by the main controller, and then transmits it to the FOC and the torque regulation module to obtain the target angle position, speed, and torque information of the motor rotation. At the same time, the FOC and the torque regulation module also upload the position, speed, torque, and sensor information to the Manchester encoding and decoding circuit in real time. After encoding by the Manchester encoding and decoding circuit, the data is transmitted to the main controller through the transmitting data line of the communication interface. The maximum data transmission rate of Manchester encoding reaches 10 MHz, which is 10 times the rate of the CAN bus. Fast and real-time communication is beneficial for the robot joint to receive control commands and data in real time, and is also beneficial for the main controller to quickly receive the feedback data of the joint, making the joint movement more accurate and fast, creating low-delay conditions for the robot to achieve various anthropomorphic actions.

[0022] The FOC control strategy of the brushless DC motor is relatively mature, mainly divided into three rotation control modes: position control mode, speed control mode, and torque control mode. The FOC and the torque regulation module integrate a PID (Proportional-Integral-Derivative control algorithm) loop controller. The FOC control has three loop controls: a current loop, a position loop, and a speed loop. The current loop obtains the current information of the three coils of the motor through two-phase current sampling. After the current is converted and PID operation is performed, the voltage signal of each coil of the motor at the next moment is obtained. The voltage signal is converted into the duty cycle output of three high-frequency PWM pulses. The duty cycle of the high-frequency PWM pulses controls the switching of the power transistor array, and its average voltage is the voltage signal to be controlled. The voltage applied to the motor coil will generate a corresponding current, and this current generates a torque to drive the motor rotor to rotate, thereby realizing the current loop control of the motor.

[0023] As known from the knowledge of electromagnetic force, a current perpendicular to the magnetic field generates a motor torque. Therefore, controlling the current can directly control the magnitude and direction of the magnetic field of the rotor, and thus directly control the magnitude of the motor torque. However, the motor torque is used to overcome friction, provide acceleration, etc., and not all torques are used to transmit the output of the reducer. However, there is a linear relationship between the motor torque and the output torque of the reducer at low speeds, and the magnitude of the output torque can be calculated from the torque of the motor. The position and speed loops receive the encoded information of the motor to obtain the angular position and speed data of the motor, and obtain the voltage control signal for controlling the rotational angular position and speed of the rotor at the next moment through PID operation. Similarly, the voltage control signal is converted into the duty cycle output of 3 PWM pulses, and the corresponding voltage control signal is obtained after passing through the power transistor switch. This voltage control signal is applied to the motor coil to generate a current to drive the motor to rotate to the target position and speed. The integrated FOC control of the motor can call different control modes according to different control commands, can process multiple sensor information inputs in parallel, and improve the current sampling frequency. The integrated FOC control has a faster response speed than using an MCU control, and is more stable, not prone to crashing and program runaway, and has higher reliability. It is combined with a unique torque regulation operation to achieve a more anthropomorphic torque control.

[0024] In this embodiment, the drive circuit receives the 3 PWM pulse signals output by the FOC and torque regulation module, and converts them into the gate drive signals of 6 power transistors N1-N6, so that the pulses of U, V, and W have the same duty cycle as the 3 PWM pulse signals.

[0025] In this embodiment, in addition to the 6 power transistors that realize the motor drive function, the power transistor array in the robot joint module also adds current sampling transistors N2S and N4S. The current sampling transistors and the power transistors need to be devices with the same temperature effect and the same type (for example, when the power transistor uses a VDMOS transistor, the sampling transistor also uses a VDMOS transistor; when the power transistor uses a GaN transistor, the sampling transistor also uses a GaN transistor of the same manufacturer). The internal resistance of the sampling transistor is larger than that of the power transistor, and it is a reduced-size version of the power transistor. The sampling transistor can also be fabricated on the same wafer as the power transistor, and the sampling transistor is a unit of the power transistor. Thus, under the drive of the same gate-source voltage, the over-current magnitudes of the power transistor and the sampling transistor with the same drain voltage are inversely proportional to the internal resistance. For example, if the internal resistance ratio of the power transistor and the sampling transistor is 1:100000, the current ratio of the power transistor and the sampling transistor is 100000:1. In this way, by adding a sampling transistor to detect the power transistor current, the additional loss brought by the sampling resistor can be avoided, and the cost can also be reduced. The cost of the small-size sampling transistor is much lower than that of the high-precision high-power resistor. If a GaN power transistor is used, the voltage drop of the sampling resistor can also be avoided, and the gate-source voltage of the GaN power transistor will be reduced, thereby increasing the on-resistance of the GaN power transistor and increasing the temperature rise.

[0026] In this embodiment, the current sampling circuit is connected to the drain terminals of power transistors N2 and N4 and the drain terminals of sampling transistors N2S and N4S. By inputting a current to the drain terminal of the sampling transistor, the drain voltages of the power transistor and the sampling transistor are controlled to be the same, and the current flowing through the sampling transistor is obtained. It can be known that the current of the sampling transistor is proportional to the current of the power transistor, so as to obtain the current information of the power transistor. At the same time, the current sampling circuit can also directly detect the voltage at the drain terminal of the power transistor, and can accurately control the dead time of the power transistor, avoid the short - circuit of the power transistors, and prevent the power transistors from being turned on under abnormal conditions, resulting in large - current burnout.

[0027] As Figure 3As shown, devices N2 and N2S are the power transistor and sampling transistor in the power transistor array. The current sampling circuits of power transistor N2 and sampling transistor N2S are the same. Here, a group of current sampling circuits is taken for illustration. Resistor R1 and capacitor C1 are externally added RC filtering circuits, which are used to filter and limit the current of the drain voltage of power transistor N2. Among them, capacitor C1 can be designed inside the chip and is not necessary when added externally. One end of resistor R1 is connected to the drain of power transistor N2, and the other end is connected to the a input terminal of the current sampling circuit. The a terminal of the current sampling circuit is connected to a voltage regulator device or voltage regulator circuit Z1, which cooperates with external resistor R1 to achieve the voltage limiting function of input port a. The voltage withstand requirement of the a input terminal of the current sampling circuit is reduced. The drain of switch control transistor Nm1 is connected to the a terminal, the gate is connected to the g2_ctrl control signal, and the source is connected to the overcurrent detection circuit and the positive input terminal Vp of operational amplifier U1. When power transistor N2 is turned on, the motor current flows through power transistor N2 and a voltage drop will be generated at the drain. This voltage drop is usually less than 1V. At this time, the g2_ctrl control signal controls transistor Nm1 to turn on. When stable, almost no current flows through resistor R1 and transistor Nm1, and the Vp voltage is equal to the voltage of the a input terminal. A threshold value can be set for the Vp voltage when the power transistor is turned on. When the overcurrent detection circuit detects that the Vp voltage is greater than the set threshold value, it is determined that the current of power transistor N2 is abnormally large, and then power transistor N2 is forcibly turned off to avoid burning out the power transistor due to overcurrent. The a input terminal is simultaneously connected to the abnormality detection module, and the drain voltage of power transistor N2 is judged by detecting the voltage of the a input terminal. The abnormality detection module outputs a judgment signal on whether the drain voltage of the power transistor is abnormal, which is used for the turn-on judgment of the power transistor. The negative input terminal Vn of operational amplifier U1 is connected to the b input terminal, that is, the drain of sampling transistor N2S. The output of operational amplifier U1 controls transistor Nm2 to turn on so that the voltage of the b terminal is exactly equal to the voltage of the Vp terminal. At this time, the current flowing through transistor Nm2 multiplied by the internal resistance of sampling transistor N2S is equal to the voltage of the b terminal, and is also equal to the current flowing through power transistor N2 multiplied by the internal resistance of the power transistor. Since power transistor N2 and sampling transistor N2S have the same structure, the ratio of their internal resistances can be kept stable and is not affected by temperature and gate control voltage. It can be known that if the ratio of internal resistances is constant, the currents of the power transistor and the sampling transistor are proportional. The magnitude of the current of transistor Nm2 represents the current of the power transistor. The current of transistor Nm2 passes through a current-to-voltage and calibration module and then outputs a voltage signal. The trimming and calibration control signal is input to calibrate the ratio of internal resistances and the coefficient of current-to-voltage conversion. The finally output voltage signal has a set coefficient relationship with the current of power transistor N2. So that the next-stage digital-to-analog conversion circuit can obtain the corresponding power current information by detecting the output voltage signal. In this way, the current sampling circuit in this embodiment realizes high-precision sampling of the power transistor current without a sampling resistor. At the same time, it can also judge the overcurrent and turn-on of the power transistor, avoid the power transistor working under abnormal conditions, and improve the reliability of the power transistor. Omitting the sampling resistor of the power transistor can also improve the efficiency of the power transistor array, reduce losses and heat generation.In addition, usually, the power tube and the sampling tube can be integrated into one device in a customized manner, which can further improve the accuracy of current sampling, increase the integration level and reduce costs.

[0028] Embodiment 2 Based on the above-mentioned robot joint power chip, the present invention also provides a driving method for a motor of a robot joint module, including the following steps: S1. Receive the data on the data line through the communication interface of the Manchester encoding and decoding circuit, decode it, and obtain the commands and data information transmitted by the main controller of the robot joint module; S2. The FOC and torque regulation module receives the decoded information of the Manchester encoding and decoding circuit to obtain the target angle position, speed, and torque information for the motor to rotate; S3. The FOC and torque regulation module uploads the target angle position, speed, and torque information to the Manchester encoding and decoding circuit in real time. After encoding by the Manchester encoding and decoding circuit, the data is sent to the main controller through the sending data line of the communication interface; S4. The FOC and torque regulation module samples the operation information of the motor of the robot joint module, converts the operation information into voltage control information, and then outputs a high-frequency PWM pulse duty ratio through calculation to control the power tube array of the robot joint module; wherein, the operation information is current information or encoded information; S5. The average voltage output by the power tube array is applied to the coil of the motor of the robot joint module to generate a corresponding current, and the current generates a torque to drive the rotor of the motor of the robot joint module to rotate.

[0029] Through the above design, the present invention enables the data communication between the main controller of the robot joint module and the joint module to be real-time, with a faster transmission rate and good anti-interference performance. The FOC control of the motor responds more quickly, the control delay of the joint motor is greatly reduced, the power tube turn-on protection function is added, and the efficiency and the reliability of the power tube array are improved. At the same time, the size of the robot joint module is also greatly reduced, the cost is reduced, the loss is reduced, the heat generation is reduced, and the reliability is improved.

[0030] The above embodiments are only one of the preferred embodiments of the present invention and should not be used to limit the protection scope of the present invention. Any meaningless changes or polishings made on the main design idea and spirit of the present invention, as long as the technical problems solved are still the same as those of the present invention, should be included in the protection scope of the present invention.

Claims

1. A robot joint power chip, characterized in that, It includes an FOC and torque regulation module, as well as an LDO circuit, a Manchester encoding and decoding circuit, a current sampling circuit, and a drive circuit that are both connected to the FOC and torque regulation module; among them, the Manchester encoding and decoding circuit is connected to the main controller of the robot through a communication interface, the LDO circuit is also connected to the Manchester encoding and decoding circuit and the drive circuit, the current sampling circuit and the drive circuit are connected to the power transistor array of the robot joint module, and FOC is field-oriented control.

2. The robotic joint power chip according to claim 1, characterized in that, The current sampling circuit includes a control transistor Nm1 whose gate is connected to the FOC and torque regulation module, an operational amplifier U1 whose positive input terminal Vp is connected to the source of the control transistor Nm1, an overcurrent detection circuit connected to the source of the control transistor Nm1, a control transistor Nm2 whose gate is connected to the output of the operational amplifier U1, a current-to-voltage and calibration circuit connected to the drain of the control transistor Nm2, an anomaly detection circuit connected to the drain of the control transistor Nm1, a resistor R1 and a capacitor C1 whose one ends are connected to the drain of the control transistor Nm1, and a voltage stabilization circuit Z1 whose one end is connected to the drain of the control transistor Nm1 and the other end is grounded; among them, the other end of the capacitor C1 is grounded, the negative input terminal Vn of the operational amplifier U1, the other end of the resistor R1, and the source of the control transistor Nm2 are connected to the power transistor array of the robot joint module; the anomaly detection circuit, the overcurrent detection circuit, and the current-to-voltage and calibration circuit are all connected to the FOC and torque regulation module.

3. The power chip for a robot joint according to claim 2, wherein, The FOC and torque regulation module integrates a PID loop controller, and the FOC control has three loop controls: a current loop, a position loop, and a speed loop; among them, the current loop obtains the current information of the coils of the motor of the robot joint module through two-phase current sampling, and after the current is converted and PID operation is performed, the voltage control signal of each coil of the motor at the next moment is obtained; the position loop and the speed loop use the encoding information of the motor to obtain the angular position and speed data of the motor of the robot joint module respectively, and after PID loop operation, the voltage control signal for controlling the rotation angle position and speed of the rotor of the motor M1 at the next moment is obtained.

4. A driving method for a motor of a robot joint module, characterized in that, Using the joint power chip as described in claim 3, it includes the following steps: S1, Receive the data on the data line through the communication interface of the Manchester encoding and decoding circuit, decode it, and obtain the command and data information transmitted by the main controller of the robot joint module; S2, The FOC and torque regulation module receive the decoded information of the Manchester encoding and decoding circuit, and obtain the target angular position, speed, and torque information of the motor rotation; S3, The FOC and torque regulation module uploads the target angular position, speed, and torque information to the Manchester encoding and decoding circuit in real time. The Manchester encoding and decoding circuit encodes it and sends the data to the main controller through the sending data line of the communication interface; S4, The FOC and torque regulation module samples the operation information of the motor of the robot joint module, converts the operation information into voltage control information, and then outputs a high-frequency PWM pulse duty cycle through operation to control the power transistor array of the robot joint module; among them, the operation information is current information or encoding information; At S5, the average voltage output by the power transistor array is applied to the coil of the motor of the robot joint module to generate a corresponding current, and the current generates a torque to drive the rotation of the rotor of the motor of the robot joint module.

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