Humanoid robot motor brake protection device

Abstract

This application discloses a motor brake protection device for a humanoid robot, including a control module, a comparator module, an OR circuit, and an energy discharge circuit. The control module performs ADC sampling on the motor bus power supply voltage. When the bus voltage is detected to be higher than a first threshold voltage, it outputs an EN enable signal, which opens the energy discharge circuit and discharges spikes through a high-power resistor. When the bus voltage is detected to be lower than a second threshold voltage, it outputs an EN enable signal and closes the energy discharge circuit. The comparator compares the collected motor bus power supply voltage with a reference voltage. When the bus voltage is higher than a third threshold voltage, it outputs an EN enable signal, which opens the energy discharge circuit and discharges spikes through a high-power resistor. When the bus voltage is detected to be lower than a fourth threshold voltage, it outputs an EN enable signal and closes the energy discharge circuit. This application employs dual protection logic, making the discharge protection safer and more reliable.

Description

Technical Field

[0001] This application belongs to the field of humanoid robot technology, and more specifically, relates to a motor brake protection device for a humanoid robot. Background Technology

[0002] Currently, the joint motors of humanoid robots generate back electromotive force during braking or deceleration, which may threaten the drive circuitry. To address this issue, the industry primarily employs the following two approaches: (1) Use of high-voltage motor drivers and power devices: By selecting motor drivers and power semiconductor devices with high voltage withstand values, the high voltage generated by the back electromotive force can be directly absorbed. This solution is usually suitable for humanoid robot companies with the ability to develop their own joint motors, and can carry out high-voltage compatibility design at the system level from the motor design and drive topology level.

[0003] (2) Connect a large-capacity capacitor in parallel with the motor power supply bus: For example, add an electrolytic capacitor with a capacity of 10,000 μF or more to the bus. Utilize the energy storage characteristics of the capacitor to absorb the reverse energy generated during braking, thereby suppressing voltage spikes and protecting the motor driver and other sensitive circuits from overvoltage impact.

[0004] Although method one can directly withstand the high voltage generated by the reverse electromotive force at the circuit level, its disadvantages are quite obvious: (1.1) Motor selection limitations: At present, the overvoltage protection threshold of the joint motor itself is usually designed to be around 60V. There are few high-voltage motor models available on the market, and the compatibility is poor; (1.2) High cost and few options: The selection of high-voltage power devices and drive ICs is limited, and the price is significantly higher than that of conventional specifications, resulting in an increase in overall cost; (1.3) Reliability risk: Long-term exposure to high-voltage spike impacts will cause the devices to gradually deteriorate, shorten their lifespan, and reduce the reliability of the system, making it difficult to meet the requirements of humanoid robots for long-term stable operation.

[0005] Method 2 uses capacitors to absorb energy to suppress voltage spikes, which is a common buffering method, but it also faces the following problems: (2.1) Surge current impact: The larger the capacitance value, the larger the surge current generated at the moment of power-on, which may damage the power supply circuit. Therefore, it is necessary to add an additional surge protection design, which brings about system complexity and cost increase; (2.2) Space limitation: The humanoid robot has a compact structure and extremely limited space in the chest cavity. It is difficult to place large-volume electrolytic capacitors, which seriously affects the overall structural design; (2.3) Safety hazards: In the environment of violent movement or vibration, the external capacitors are at risk of loose connection or even falling off, which not only affects the electrical connection, but may also cause safety problems such as short circuit. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this application is to provide a motor braking protection device for humanoid robots, which aims to solve the problem that the excessive peak energy generated by the back electromotive force at the moment of motor braking in the prior art threatens the joint motor.

[0007] This application provides a motor brake protection device for a humanoid robot, including a control module, a comparison module, an OR circuit, and an energy discharge circuit. The input terminal of the control module is connected to the motor bus power supply line. The first input terminal of the comparison module is connected to the motor bus power supply line, and the second input terminal of the comparison module is used to connect to a reference voltage. The first input terminal of the OR circuit is connected to the output terminal of the control module, and the second input terminal of the OR circuit is connected to the output terminal of the comparison module. The input terminal of the energy discharge circuit is connected to the output terminal of the OR circuit. The control module performs ADC sampling on the motor bus power supply voltage. When the bus voltage is detected to be higher than a first threshold voltage, it outputs E. The N enable signal is used to open the energy discharge circuit through an OR circuit, thereby discharging the spike through the high-power resistor; when the bus voltage is detected to be lower than the second threshold voltage, the EN enable signal is output, and the energy discharge circuit is closed through an OR circuit; the comparison module is used to compare the collected motor bus power supply voltage with the reference voltage, and when the bus voltage is higher than the third threshold voltage, the EN enable signal is output, and the energy discharge circuit is opened through an OR circuit, thereby discharging the spike through the high-power resistor; when the bus voltage is detected to be lower than the fourth threshold voltage, the EN enable signal is output, and the energy discharge circuit is closed through an OR circuit.

[0008] Among them, the first threshold voltage is greater than the second threshold voltage; the third threshold voltage is greater than the fourth threshold voltage. The third threshold voltage is greater than the first threshold voltage, and the fourth threshold voltage is less than the second threshold voltage.

[0009] In this application, the control module can be an MCU, which performs high-speed sampling of the motor bus power supply voltage at the millisecond level.

[0010] Furthermore, the comparison module includes comparator U2, resistors R1, R2, R3, R4, R5, R6, and R7, capacitors C1 and C2, and diodes D1 and D2. Resistors R1, R2, and R3 are connected in series between the motor bus power supply voltage and ground. Diode D1 is connected between the series connection of resistors R2 and R3 and ground. The non-inverting input of comparator U2 is connected to the series connection of resistors R2 and R3 through resistor R4. The inverting input of comparator U2 is connected to the reference voltage through resistor R5. The power supply terminal of comparator U2 is connected to the power supply voltage V2. The output terminal of comparator U2 is connected to the non-inverting input terminal of comparator U2 through resistor R7. Diode D2 is connected between the inverting input terminal of comparator U2 and ground. Capacitors C1 and C2 are connected in parallel between the power supply voltage V2 and ground. Resistor R6 is connected between the power supply voltage V2 and the output terminal of comparator U2.

[0011] Preferably, comparator U2 can be a hysteresis comparator.

[0012] Furthermore, the OR circuit includes: OR gate U1, resistors R8, R9, R10, R11, and capacitor C3; the first input terminal of OR gate U1 is connected to the output terminal of the control module through resistor R8, the second input terminal is connected to the output terminal of the comparator module through resistor R9, the power supply terminal of OR gate U1 is connected to the power supply voltage V2, and the output terminal of OR gate U1 serves as the output terminal of the OR circuit; resistor R10 is connected between the second input terminal of OR gate U1 and ground; resistor R11 is connected between the first input terminal of OR gate U1 and ground; and capacitor C3 is connected between the power supply voltage V2 and ground.

[0013] Furthermore, the energy discharge circuit includes: MOSFET Q1, resistors R12, R13, and R14, capacitors C4 and C5; the gate of MOSFET Q1 is connected to the output terminal of the OR circuit through resistor R12, the source is grounded, and the drain is connected to one end of interface J1; capacitor C4 and resistor R13 are connected in parallel between the gate of MOSFET Q1 and ground, and resistor R14 and capacitor C5 are connected in series between the drain of MOSFET Q1 and ground.

[0014] Compared with existing technologies, the technical solution conceived in this application provides safer and more reliable discharge protection by employing a dual protection logic using an MCU and a comparator. Specifically, it offers the following technical advantages: (1) This application adopts dual protection logic to make the discharge protection safer and more reliable.

[0015] (2) The energy discharge circuit used in this application is more reasonable and has long-term stability compared with the withstand voltage hard impedance scheme. Energy discharge can ensure that the components work within the normal range. Without energy release, the components are essentially working at their limits, and long-term extreme work will definitely result in lower stability.

[0016] (3) The protection circuit used in this application requires fewer components and does not take up much space, making it convenient for humanoid robots to be integrated and installed.

[0017] (4) The dual protection logic circuit used in this application is inexpensive and can be adapted to various types of joint motors. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the principle structure of the humanoid robot motor brake protection device provided in this application; Figure 2 This is a specific circuit diagram of the comparison module in the humanoid robot motor brake protection device provided in this application; Figure 3 This is a specific circuit diagram of the motor brake protection device for the humanoid robot provided in this application; Figure 4 This is a detailed circuit diagram of the energy discharge circuit in the humanoid robot motor brake protection device provided in this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] This application addresses the issue of peak energy during joint motor braking by employing relevant circuitry and control logic to ensure the rapid and effective dissipation of this peak energy, thereby guaranteeing the safety and reliability of the robot's joint motor and system. Specifically, when a humanoid robot's motor performs a braking action, the rotor's continuous rotation due to inertia induces a back electromotive force (EMF). If not properly handled, excessively high EMF can impact core components such as the motor driver and power devices, potentially leading to circuit failures or performance degradation. This application focuses on this technical challenge by optimizing the braking circuit topology and dynamic control strategies to quickly and safely dissipate the energy converted from the back EMF through an adaptive load in a controllable manner. This application utilizes dual protection logic—using both an MCU and a comparator—to ensure timely dissipation of peak energy and protect core components from damage; it innovatively solves the problem of efficiently dissipating the back EMF during motor braking.

[0021] Figure 1A schematic diagram of the humanoid robot motor brake protection device provided in this application is shown. For ease of explanation, only the parts relevant to this application are shown, and are described in detail below: A humanoid robot motor brake protection device includes an MCU, a comparator, an OR circuit, and an energy discharge circuit. The input terminal of the MCU is connected to the motor bus power supply line. The first input terminal of the comparator is connected to the motor bus power supply line, and the second input terminal of the comparator is used to connect to a reference voltage. The first input terminal of the OR circuit is connected to the output terminal of the MCU, and the second input terminal of the OR circuit is connected to the output terminal of the comparator. The input terminal of the energy discharge circuit is connected to the output terminal of the OR circuit. The MCU is used to perform ADC sampling on the motor bus power supply voltage. When the bus voltage is detected to be higher than a first threshold voltage, an EN enable signal is output. The comparator is used to compare the acquired motor bus power supply voltage with the reference voltage. When the bus voltage is higher than the third threshold voltage, it outputs an EN enable signal and opens the energy discharge circuit through an OR circuit, thereby discharging the spike through the high-power resistor. When the bus voltage is lower than the fourth threshold voltage, it outputs an EN enable signal and closes the energy discharge circuit through an OR circuit.

[0022] Among them, the first threshold voltage is greater than the second threshold voltage; the third threshold voltage is greater than the fourth threshold voltage. The third threshold voltage is greater than the first threshold voltage, and the fourth threshold voltage is less than the second threshold voltage.

[0023] Furthermore, the MCU can perform high-speed sampling of the motor bus power supply voltage at the millisecond level. Specifically, high-speed sampling is performed through the ADC sampling module in the MCU. The maximum conversion rate of the ADC sampling module is 1MHz, which is approximately 1µs.

[0024] Figure 2The circuit diagram of the comparison module in the humanoid robot motor brake protection device provided in this application is shown. The comparison module includes comparator U2, resistors R1, R2, R3, R4, R5, R6, and R7, capacitors C1 and C2, diodes D1 and D2. Resistors R1, R2, and R3 are connected in series between the motor bus power supply voltage and ground. Diode D1 is connected between the series connection of resistors R2 and R3 and ground. The non-inverting input terminal of comparator U2... Resistor R4 is connected to the series connection of resistors R2 and R3; the inverting input of comparator U2 is connected to the reference voltage through resistor R5; the power supply terminal of comparator U2 is connected to the power supply voltage V2; the output terminal of comparator U2 is connected to the non-inverting input terminal of comparator U2 through resistor R7; diode D2 is connected between the inverting input terminal of comparator U2 and ground; capacitors C1 and C2 are connected in parallel between the power supply voltage V2 and ground; and resistor R6 is connected between the power supply voltage V2 and the output terminal of comparator U2.

[0025] A further preferred option is to use a hysteresis comparator.

[0026] Figure 3 The diagram shows a specific circuit diagram of the OR circuit in the humanoid robot motor brake protection device provided in this application; the OR circuit includes: OR gate U1, resistors R8, R9, R10, R11 and capacitor C3; the first input terminal of OR gate U1 is connected to the output terminal of the control module through resistor R8, the second input terminal is connected to the output terminal of the comparator module through resistor R9, the power supply terminal of OR gate U1 is connected to the power supply voltage V2, and the output terminal of OR gate U1 serves as the output terminal of the OR circuit; resistor R10 is connected between the second input terminal of OR gate U1 and ground; resistor R11 is connected between the first input terminal of OR gate U1 and ground; capacitor C3 is connected between the power supply voltage V2 and ground.

[0027] Figure 4 The diagram shows a specific circuit diagram of the energy discharge circuit in the humanoid robot motor brake protection device provided in this application. The energy discharge circuit includes: MOSFET Q1, resistors R12, R13, and R14, capacitors C4 and C5. The gate of MOSFET Q1 is connected to the output terminal of the OR circuit through resistor R12, the source is grounded, and the drain is connected to one end of interface J1. The other end of J1 is connected to the braking resistor. Capacitor C4 and resistor R13 are connected in parallel between the gate of MOSFET Q1 and ground, and resistor R14 and capacitor C5 are connected in series between the drain of MOSFET Q1 and ground.

[0028] To further illustrate this point, specific embodiments are described in detail below: During the operation of a humanoid robot, when the motor stops, it generates a large spike pulse. Taking a 48V joint motor as an example, the spike pulse may be around 80V, but most 48V motors have a withstand voltage / overvoltage protection point of 60V.

[0029] The MCU performs high-speed sampling of the 48V bus power supply voltage at the millisecond level. When it detects that the bus voltage is higher than 58V, it outputs an EN enable signal to the OR circuit, thereby opening the discharge channel. At this time, the peak is discharged through the high-power resistor. When the bus voltage drops to 55V, the discharge channel is closed, and the current discharge process ends.

[0030] When the peak energy pulse is large and short in duration, the pure hardware hysteresis comparator circuit will respond quickly. When the bus voltage is detected to be higher than 59V, it will output an EN enable signal to open the discharge channel; when the bus voltage is lower than 54V, it will close the channel.

[0031] Since the reliability of hardware protection circuits is higher than that of software protection logic, in this system, MCU software sampling and discharge is the first-level protection point, and hardware discharge is the second-level protection point, forming a dual protection mechanism; moreover, the first-level and second-level protection points form a redundant protection channel, which can serve as alternative protection mechanisms for each other, thereby making the protection circuit more reliable.

[0032] The motor brake protection device provided in this application uses relevant circuits to dissipate peak energy, protecting the robot's internal circuits and motor, and without taking up much chest cavity space.

[0033] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A motor brake protection device for a humanoid robot, characterized in that, This includes a control module, a comparison module, or circuitry and an energy discharge circuitry; The input terminal of the control module is connected to the motor bus power line, the first input terminal of the comparison module is connected to the motor bus power line, the second input terminal of the comparison module is used to connect to the reference voltage, the first input terminal of the OR circuit is connected to the output terminal of the control module, the second input terminal of the OR circuit is connected to the output terminal of the comparison module, and the input terminal of the energy discharge circuit is connected to the output terminal of the OR circuit. The control module is used to sample the motor bus power supply voltage using an ADC. When the bus voltage is detected to be higher than the first threshold voltage, an EN enable signal is output, and the energy discharge circuit is turned on through an OR circuit, thereby discharging the spike through the high-power resistor. When the bus voltage is detected to be lower than the second threshold voltage, an EN enable signal is output, and the energy discharge circuit is turned off through an OR circuit. The comparison module is used to compare the collected motor bus power supply voltage with the reference voltage. When the bus voltage is higher than the third threshold voltage, it outputs an EN enable signal and opens the energy discharge circuit through an OR circuit, thereby discharging the spike through the high-power resistor. When the bus voltage is detected to be lower than the fourth threshold voltage, it outputs an EN enable signal and closes the energy discharge circuit through an OR circuit.

2. The humanoid robot motor brake protection device as described in claim 1, characterized in that, The first threshold voltage is greater than the second threshold voltage; the third threshold voltage is greater than the fourth threshold voltage.

3. The humanoid robot motor brake protection device as described in claim 2, characterized in that, The third threshold voltage is greater than the first threshold voltage, and the fourth threshold voltage is less than the second threshold voltage.

4. The humanoid robot motor brake protection device as described in any one of claims 1-3, characterized in that... The control module is an MCU, which performs high-speed sampling of the motor bus power supply voltage at the millisecond level.

5. The humanoid robot motor brake protection device as described in any one of claims 1-3, characterized in that, The comparison module includes comparator U2, resistors R1, R2, R3, R4, R5, R6, and R7, capacitors C1 and C2, diode D1, and diode D2. Resistors R1, R2, and R3 are connected in series between the motor bus power supply voltage and ground, and diode D1 is connected between the series connection of resistors R2 and R3 and ground. The non-inverting input of comparator U2 is connected to the series connection of resistors R2 and R3 through resistor R4; The inverting input of comparator U2 is connected to the reference voltage through resistor R5; the power supply terminal of comparator U2 is connected to the power supply voltage V2; the output terminal of comparator U2 is connected to the non-inverting input terminal of comparator U2 through resistor R7. Diode D2 is connected between the inverting input of comparator U2 and ground; Capacitors C1 and C2 are connected in parallel between the power supply voltage V2 and ground, and resistor R6 is connected between the power supply voltage V2 and the output terminal of comparator U2.

6. The humanoid robot motor brake protection device as described in claim 5, characterized in that, The comparator U2 is a hysteresis comparator.

7. The humanoid robot motor brake protection device as described in claim 1, characterized in that, The OR circuit includes: OR gate U1, resistor R8, resistor R9, resistor R10, resistor R11 and capacitor C3; The first input terminal of OR gate U1 is connected to the output terminal of the control module through resistor R8, the second input terminal is connected to the output terminal of the comparator module through resistor R9, the power supply terminal of OR gate U1 is connected to the power supply voltage V2, and the output terminal of OR gate U1 serves as the output terminal of the OR circuit. Resistor R10 is connected between the second input terminal of OR gate U1 and ground; Resistor R11 is connected between the first input terminal of OR gate U1 and ground; Capacitor C3 is connected between the power supply voltage V2 and ground.

8. The humanoid robot motor brake protection device as described in claim 1, characterized in that, The energy discharge circuit includes: MOSFET Q1, resistor R12, resistor R13, resistor R14, capacitor C4, and capacitor C5; The gate of MOSFET Q1 is connected to the output terminal of the OR circuit through resistor R12, the source is grounded, and the drain is connected to one end of interface J1. Capacitor C4 and resistor R13 are connected in parallel between the gate of MOSFET Q1 and ground, and resistor R14 and capacitor C5 are connected in series between the drain of MOSFET Q1 and ground.

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