A method for strengthening the anti-radiation of brushless motor drive for robots

Abstract

The present invention belongs to the field of robot anti-radiation technology, and specifically relates to an anti-radiation reinforcement method for a brushless motor drive for a robot, comprising the following steps: step S1, replacing the key components of the brushless motor drive with anti-radiation components; step S2, anti-radiation design of the circuit driven by the brushless motor; step S3, performing embedded development at the software level, and using control means to protect the circuit. The present invention can increase the cumulative anti-radiation dose of the robot motor drive from about 50Gy to more than 2000Gy, so that the robot can replace the staff in strong radiation places in most cases, reduce the radiation dose of the staff and improve work efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of robot anti-radiation, and in particular relates to an anti-radiation reinforcement method for a robot driven by a brushless motor. Background Art

[0002] At present, nuclear emergency response, radiation monitoring, radiation decontamination and other work in radiation sites such as nuclear power plants, nuclear facilities, and radiation devices are mainly completed by workers entering the radiation sites, which will cause additional radiation doses to personnel. With the development of robot technology, robots can play an increasingly important role in these application scenarios, thereby reducing the radiation dose of personnel and improving work efficiency. However, the current application of robots in strong radiation fields is still relatively limited. The main reason is that they are limited by their radiation resistance. The key part is the motor drive on the robot. Generally speaking, the motor drive will be damaged if it works for a long time in a strong radiation field. The damage to the motor drive means that the motion mechanism is abnormal, and there may be a decrease in control accuracy, or even abnormal operation, such as the structure cannot move, out of control, etc., which will cause further losses in severe cases. Therefore, it is necessary to reinforce the robot's motor drive with radiation resistance, improve its radiation resistance, and extend the robot's survival time in the radiation field. Summary of the invention

[0003] Most of the current robots are used in ordinary industrial applications and are used in low-radiation environments, so there is no need to consider their radiation resistance. When robots are used in radiation environments, radiation resistance becomes particularly important. The purpose of the present invention is to provide an anti-radiation reinforcement method. Aiming at the radiation resistance problem of the robot motor drive, a variety of technical approaches are used to reinforce the robot's motor drive for radiation resistance, improve its radiation resistance, and extend the robot's survival time in the radiation field, so that robot technology is more and more widely used in application scenarios such as nuclear emergency, radiation monitoring, and radiation decontamination, thereby reducing the radiation dose of personnel and improving work efficiency.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is a method for anti-radiation reinforcement of a robot driven by a brushless motor, comprising the following steps:

[0005] Step S1, replacing the key components of the brushless motor drive with anti-radiation components;

[0006] Step S2, designing the anti-radiation of the brushless motor driving circuit;

[0007] Step S3, carry out embedded development at the software level and use control means to perform circuit protection.

[0008] Furthermore, in step S1, the key components that need to be replaced include power transistors, which are replaced with power transistors using a gallium nitride process.

[0009] Furthermore, in step S1, the key components that need to be replaced also include replacing chips with a process of 40 nanometers or above with chips with a process of 40 nanometers or below.

[0010] Further, in the step S2, it includes radiation resistance design for the precursor circuit; the brushless motor drive includes a main control circuit and a full-bridge drive circuit and a feedback circuit connected to the main control circuit, and also includes a brushless motor connected to the full-bridge drive circuit and the feedback circuit, and the precursor circuit is connected to the main control circuit and the full-bridge drive circuit; the precursor circuit is used to control the full-bridge drive circuit, and the precursor circuit is composed of a high-frequency isolation transformer made of metal and an analog electronic precursor circuit. A judgment algorithm is provided in the main control circuit, and the main control circuit uses the judgment algorithm to judge the speed and PWM duty cycle of the brushless motor according to the control instruction and the input signal of the feedback circuit. When the speed and the PWM duty cycle are greater than the preset value after calculation, the judgment algorithm selects to use the high-frequency isolation transformer to control the full-bridge drive circuit, and when the speed and the PWM duty cycle are less than the preset value after calculation, the judgment algorithm selects to use the analog electronic precursor circuit to control the full-bridge drive circuit.

[0011] Furthermore, step S2 also includes a monitoring algorithm for the brushless motor, in which a preset function regarding the PWM duty cycle and the rotational speed is provided, and the monitoring algorithm can also perform function fitting on the PWM duty cycle and the rotational speed; when the analog electronic precursor circuit is used to control the full-bridge drive circuit, when the value of the function fitting and the value of the preset function produce a deviation exceeding a specified limit, it is considered that the brushless motor is operating abnormally, at which time the analog electronic precursor circuit is stopped and the high-frequency isolation transformer is used to control the full-bridge drive circuit, and at the same time, the main control circuit locks the lowest PWM duty cycle within the range that the high-frequency isolation transformer can use.

[0012] Furthermore, in step S3, the instructions and feedback information of the brushless motor drive are monitored and verified by system-level software, and when there are abnormal signals, the instructions and information are reconfirmed, or preset emergency program instructions are started.

[0013] The beneficial effects of the present invention are:

[0014] The anti-radiation reinforcement method of the robot's brushless motor drive can increase the cumulative anti-radiation dose of the robot's motor drive from about 50Gy to more than 2000Gy, so that the robot can replace workers in strong radiation places in most cases, reduce the radiation dose of workers and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a brushless motor drive reinforced by the anti-radiation reinforcement method for brushless motor drive for robots provided by the present invention (the reinforcement content in the figure includes a high-frequency isolation transformer and an analog electronic precursor circuit);

[0016] Figure 2 Yes Figure 1 Flow chart of the software voting switching method of the precursor circuit in which "high frequency isolation transformer" and "simulated electronic precursor circuit" are selected;

[0017] Figure 3 It is a flow chart of the software control of the monitoring algorithm of the brushless motor. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] The present invention provides a method for anti-radiation reinforcement of a brushless motor driven robot, comprising the following steps:

[0020] Step S1, replacing the key components of the brushless motor drive with anti-radiation components;

[0021] Step S2, designing the anti-radiation of the brushless motor driving circuit;

[0022] Step S3, carry out embedded development at the software level and use control means to perform circuit protection.

[0023] In step S1, key components that need to be replaced include power transistors, which are replaced with power transistors using a gallium nitride process.

[0024] Brushless motors consist of many parts, one of which is the power part. Currently, most of the power transistors in the commonly used robot motor drives are silicon MOS technology, which has relatively weak radiation resistance, with a cumulative radiation dose of 50-60Gy. However, according to new research results, gallium nitride transistors have better radiation resistance.

[0025] In step S1, the key components that need to be replaced also include chips with lower nanometer technology (chips with technology of 40 nanometers or above), which are replaced with chips with higher nanometer technology. According to the results of experiments and literature research, chips with higher nanometer technology have good total dose performance, so chips with technology of 40 nanometers or below are mainly selected.

[0026] In step S2, the anti-radiation design of the precursor circuit is included; the brushless motor drive includes a main control circuit and a full-bridge drive circuit and a feedback circuit connected to the main control circuit, and also includes a brushless motor connected to the full-bridge drive circuit and the feedback circuit, and the precursor circuit is connected to the main control circuit and the full-bridge drive circuit; the precursor circuit is used to control the full-bridge drive circuit driven by the brushless motor, and the precursor circuit is composed of a high-frequency isolation transformer made of metal and an analog electronic precursor circuit; a judgment algorithm is provided in the main control circuit, and the main control circuit uses the judgment algorithm to judge the speed and PWM duty cycle of the brushless motor according to the control instruction and the input signal of the feedback circuit (that is, "software voting switching", see the specific method Figure 2 ), when the speed and PWM duty cycle are greater than the preset value after calculation, the judgment algorithm chooses to use a high-frequency isolation transformer to control the full-bridge drive circuit. When the speed and PWM duty cycle are less than the preset value after calculation, the judgment algorithm chooses to use an analog electronic precursor circuit to control the full-bridge drive circuit; nowadays, most full-bridge drivers use highly integrated digital circuits as precursors, most of which include structures such as charge pump circuits. Investigations and experimental tests show that this type of digital integrated circuit has an extremely low total dose level, which will cause the on-voltage applied by the upper arm transistor to be inaccurate. In the method of using a high-frequency isolation transformer plus an analog electronic precursor circuit in the present invention, the high-frequency isolation transformer is also a metal structure, and there is basically no radiation damage. However, since high-frequency isolation transformers are difficult to operate at low duty cycles, the speed regulation range is directly restricted. Therefore, under low-speed operation, a circuit based on analog electronic technology is added. According to existing research results, the radiation resistance of electronic components when they are not biased and do not provide working voltage is stronger than that when they are biased and provide working voltage. Therefore, high-frequency isolation transformers are used in most cases, and analog electronic precursor circuits (containing triode circuits) are used in a few cases, which can greatly improve practicality and total dose levels.

[0027] Step S2 also includes a monitoring algorithm for the brushless motor. The monitoring algorithm is provided with a preset function about the PWM duty cycle and the speed. The monitoring algorithm can also perform function fitting on the PWM duty cycle and the speed. When the analog electronic precursor circuit is used to control the full-bridge drive circuit, when the value of the function fitting and the value of the preset function produce a deviation exceeding a specified value (i.e., a threshold value), it is considered that the brushless motor is working abnormally. At this time, the analog electronic precursor circuit is stopped and the high-frequency isolation transformer is used to control the full-bridge drive circuit. At the same time, the main control circuit locks the lowest PWM duty cycle within the range that the high-frequency isolation transformer can use (the software control process of the monitoring algorithm is as follows: Figure 3As shown); Since the analog electronic circuit part of the precursor circuit uses more semiconductor devices, although according to the results of investigation and experimental tests, it can be determined that when the triode works in the saturation zone, its total dose level is high. If the triode is damaged, the control signal of the upper bridge arm power tube will be inaccurate, resulting in abnormal motor rotation. In order to prevent unexpected situations, a monitoring algorithm is added to the drive reinforcement method. When the motor is maintained at a low speed, an analog electronic precursor circuit is used, which has semiconductor devices such as triodes. In this state, the PWM duty cycle and the speed value fed back meet a certain functional relationship. Therefore, the duty cycle and the speed are fitted as a function. If the values ​​of the two have a certain degree of deviation, it can be characterized as abnormal operation. At this time, the analog electronic precursor circuit is stopped, and the main control circuit locks the lowest PWM duty cycle within the range that the high-frequency transformer can use. The main control circuit will send a status prompt instruction to the host computer to prompt the user to pay attention.

[0028] In step S3, the operation of the brushless motor drive of the robot requires command input and information feedback from the robot system. The commands and feedback information of the brushless motor drive are monitored and verified through embedded development or system-level software. When there are abnormal signals, the commands and information are reconfirmed, or preset emergency program commands are started, etc., thereby improving the reliability of the brushless motor drive of the robot.

[0029] The anti-radiation reinforcement method for a brushless motor driven robot provided by the present invention can select one or more technical solutions of the steps for anti-radiation reinforcement according to conditions such as the radiation dose level of the application scenario and the operation time requirement to meet the on-site operation requirements.

[0030] The device described in the present invention is not limited to the embodiments described in the specific implementation manner. Those skilled in the art may derive other implementation manners based on the technical solution of the present invention, which also fall within the technical innovation scope of the present invention.

Claims

1. A method for radiation hardening of a robot driven by a brushless motor, comprising the following steps: Step S1, replacing the key components of the brushless motor drive with anti-radiation components; Step S2, designing the anti-radiation of the brushless motor driving circuit; Step S3, performing embedded development at the software level and using control means to perform circuit protection; In the step S2, it includes the radiation resistance design of the precursor circuit; the brushless motor drive includes a main control circuit and a full-bridge drive circuit and a feedback circuit connected to the main control circuit, and also includes a brushless motor connected to the full-bridge drive circuit and the feedback circuit, and the precursor circuit is connected to the main control circuit and the full-bridge drive circuit; the precursor circuit is used to control the full-bridge drive circuit, and the precursor circuit is composed of a high-frequency isolation transformer made of metal and an analog electronic precursor circuit; a judgment algorithm is provided in the main control circuit, and the main control circuit uses the judgment algorithm to judge the speed and PWM duty cycle of the brushless motor according to the control instruction and the input signal of the feedback circuit. When the speed and the PWM duty cycle are greater than the preset value after calculation, the judgment algorithm selects to use the high-frequency isolation transformer to control the full-bridge drive circuit, and when the speed and the PWM duty cycle are less than the preset value after calculation, the judgment algorithm selects to use the analog electronic precursor circuit to control the full-bridge drive circuit.

2. The method according to claim 1, characterized in that: In the step S1, the key components that need to be replaced include power transistors, which are replaced with power transistors made in gallium nitride process.

3. The method according to claim 2, characterized in that: In the step S1, the key components that need to be replaced also include replacing chips with a process of 40 nanometers or above with chips with a process of 40 nanometers or below.

4. The method according to claim 3, wherein: The step S2 also includes a monitoring algorithm for the brushless motor, wherein a preset function regarding the PWM duty cycle and the rotational speed is provided in the monitoring algorithm, and the monitoring algorithm can also perform function fitting on the PWM duty cycle and the rotational speed; when the analog electronic precursor circuit is used to control the full-bridge drive circuit, when the value of the function fitting and the value of the preset function produce a deviation exceeding a specified limit, it is considered that the brushless motor is operating abnormally, at which time the analog electronic precursor circuit is stopped and the high-frequency isolation transformer is used to control the full-bridge drive circuit, and at the same time, the main control circuit locks the lowest PWM duty cycle within the range that the high-frequency isolation transformer can use.

5. The method according to claim 4, characterized in that: In step S3, the instructions and feedback information of the brushless motor drive are monitored and verified by the system-level software, and when there is an abnormal signal, the instructions and information are reconfirmed, or the preset emergency program instructions are started.

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