CN112398416B - A back-drive braking control method and system for a spacecraft sheave mechanism - Google Patents

Abstract

According to the reverse drive brake control method of the spacecraft rope pulley mechanism, the maximum value and the minimum value of the running speed of a motor are preset; and detecting the motor back-driving running speed in real time, and according to the relationship between the motor back-driving running speed and the maximum value and the minimum value of the motor running speed, the FPGA module circularly outputs PWM signals in different states to the driving module so as to control the motor back-driving running speed to be between the maximum value and the minimum value of the motor running speed. The motor motion speed in the back-driving process can be reduced, the back-driving speed in emergency shutdown is effectively reduced, the elastic potential energy in the steel wire rope is slowly released, and damage to a control circuit, a transmission system (a transmission gear) and the like is avoided.

Description

A back-drive braking control method and system for a spacecraft sheave mechanism

technical field

The present disclosure belongs to the technical field of aerospace, and in particular relates to a method and system for back-drive braking control of a sheave mechanism of a spacecraft.

Background technique

China will launch a Mars Landing Rover in 2020 to conduct a survey and exploration of the surface of Mars. After the landing rover safely landed on the fire surface, the ramp mechanism on the landing platform was deployed, one end was placed on the landing platform, and the other end touched the surface of Mars, forming a ramp with a certain inclination. The rover travels on a ramp mechanism and is transferred to the surface of Mars for a mobile exploration mission.

The control system of the ramp mechanism adopts strategies such as overcurrent protection. When the ramp is blocked, it can be retryed after an emergency shutdown, or it can be deployed in the opposite direction. As shown in Figure 1, the ramp mechanism component adopts the wire rope transmission method, the control system drives the motor to rotate, the motor drives the drum to rotate and pulls the wire rope, the other end of the wire rope is connected to the ramp mechanism, and the ramp mechanism is drawn out from the landing platform. exhibition. When the ramp mechanism is blocked, the control system judges the overcurrent protection and takes emergency shutdown measures. Because the wire rope is stretched to the maximum extent before shutdown, a large amount of elastic potential energy is accumulated in the wire rope. Once the control system executes emergency shutdown measures, the motor output disappears, the elastic potential energy in the wire rope will be released, and the wire rope shrinks to drive the motor to rotate in the opposite direction. According to the actual measurement, the maximum speed of the motor being driven in reverse is more than twice the rated speed, and the duration is as long as 2 to 3 seconds. The rotor of the motor is made of permanent magnet material. When the motor rotates passively at high speed, the magnetic field in the rotor cuts the stator winding at a high speed, which will generate an induced electromotive force on the stator of the motor, and the induced electromotive force will be back fed into the control circuit, which may cause the control circuit to be over-voltage burned or Control circuit components are damaged, and high-speed rotation may also cause damage to transmission gears and lubricants.

The magnitude of the induced electromotive force has a linear relationship with the magnitude of the motor backdrive speed. According to the actual measurement, the back-feed voltage in the control system caused by the reverse drive of the ramp mechanism is as high as 70V, while the minimum withstand voltage of the components in the control circuit is 75V, the margin is insufficient, and there is a greater safety hazard.

SUMMARY OF THE INVENTION

In view of this, the present disclosure proposes a method and system for back-drive braking of a spacecraft sheave mechanism, which can reduce the movement speed of the motor during the back-drive process, effectively slow down the back-drive speed during emergency shutdown, and slowly release the wire rope. The elastic potential energy can avoid damage to the control circuit, transmission system (transmission gear), etc.

According to an aspect of the present disclosure, a method for controlling back-drive braking of a sheave mechanism of a spacecraft is proposed, the method comprising:

Pre-set the maximum and minimum values of the motor running speed;

Real-time detection of the motor reverse drive running speed, according to the relationship between the motor reverse drive running speed and the maximum and minimum values of the motor running speed, the FPGA module cyclically outputs PWM signals in different states to the drive module to control the motor reverse drive. The drive operating speed is between a maximum value and a minimum value of the motor operating speed.

In a possible implementation manner, the FPGA module outputs PWM signals in different states to the drive module according to the relationship between the motor reverse drive running speed and the maximum and minimum values of the motor running speed to control the motor reverse drive. The drive operating speed is between the maximum and minimum operating speeds of the motor, including:

When the motor reverse drive running speed is greater than the maximum value of the motor running speed, the FPGA module outputs a PWM chopper signal to the drive module to generate a control signal opposite to the motor reverse drive operation, reducing the motor reverse drive running speed , so that the motor back-drive running speed is between the maximum value and the minimum value of the motor running speed;

Or, when the motor back-drive running speed is less than the minimum value of the motor running speed, the FPGA module outputs a PWM chopper signal in a shutdown state to the drive module, and controls the power switch of the drive module to disconnect, and the wire rope Driven by elastic potential energy, the back-drive running speed of the motor increases, so that the motor's back-drive running speed is between the maximum value and the minimum value of the motor running speed.

In a possible implementation manner, the method further includes: during the reverse drive braking process, the power supply switch of the drive module is in an off state, and the energy storage capacitor and the residual energy in the wire rope are used to perform reverse drive control. When the residual energy is exhausted, the motor automatically enters the stop state.

According to another aspect of the present disclosure, a back-drive braking control system for a spacecraft sheave mechanism is proposed. The system applies the above-mentioned method for controlling back-drive braking of a spacecraft sheave mechanism. The system includes: an AD acquisition module , angle sensor module, driver module and FPGA module;

Wherein, the AD acquisition module is used to collect the motor load current and send the motor load current to the FPGA module;

the angle sensor module, for collecting the angular velocity of the motor rotor, and sending the angular velocity to the FPGA module;

The drive module is used to control the motor power supply and winding drive according to the received motor power-on and power-off signals and PWM signals of the FPGA, collect the motor load current through a sampling resistor, and send the motor load current to the AD collection module;

The FPGA module is used to control the motor back-drive braking state according to the motor load current, control the motor winding drive of the drive module according to the PWM signal obtained by processing the motor angular velocity, and output the power on and off of the motor Signals to the drive module for motor power control.

In a possible implementation manner, the controlling the motor back-drive braking state according to the motor load current includes:

When the load current of the machine determines that the motor is in an overcurrent locked-rotor state, the motor is placed in a reverse drive braking state.

In a possible implementation manner, controlling the motor winding drive of the drive module according to the PWM signal obtained by processing the motor angular velocity includes:

Perform a differential operation on the motor angular velocity to obtain the motor running speed, compare the motor running speed and the expected running speed to obtain error information of the motor running speed, adjust the PWM chopper duty cycle according to the error information, and combine the PWM chopper duty cycle The ratio and PWM wave control sequence generate PWM signal to control the motor winding drive of the drive module.

In a possible implementation manner, the driving module includes: an anti-reverse diode, a power supply switch, an energy storage capacitor, a power switch and a current sampling resistor;

Wherein, the anti-reverse diode is used to prevent the transient high voltage of the driving module from being reversed to the power supply bus of the detector;

The power supply switch is used to control the power-on and power-off of the drive module circuit;

The energy storage capacitor is used to filter the voltage fluctuation during the motor control process;

The power switch is used for on-off control according to the PWM signal sent by the FPGA module, and a rotating magnetic field is formed in the stator winding of the motor to drive the motor to rotate;

The current sampling resistor is used to collect the motor load current and transmit the motor load current to the AD acquisition module.

The method for controlling the back-drive braking of the spacecraft sheave mechanism of the present disclosure is to set the maximum and minimum values of the motor running speed in advance; The relationship between the maximum value and the minimum value of the speed, the FPGA module cyclically outputs PWM signals in different states to the driving module, so as to control the motor back-drive running speed to be between the maximum value and the minimum value of the motor running speed. It can reduce the movement speed of the motor during the reverse drive process, effectively slow down the reverse drive speed during emergency shutdown, slowly release the elastic potential energy in the wire rope, and avoid damage to the control circuit, transmission system (transmission gear), etc.

Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure, and together with the description, serve to explain the principles of the disclosure.

FIG. 1 shows a schematic structural diagram of a spacecraft sheave ramp mechanism assembly according to the prior art;

2 shows a flowchart of a method for controlling back-drive braking of a sheave mechanism of a spacecraft according to an embodiment of the present disclosure;

3 shows a structural block diagram of a back-drive braking control system for a sheave mechanism of a spacecraft according to an embodiment of the present disclosure;

FIG. 4 shows a schematic block diagram of a drive module of a back-drive braking control system for a sheave mechanism of a spacecraft according to an embodiment of the present disclosure;

FIG. 5 shows a flowchart of a method for controlling back-drive braking of a sheave mechanism of a spacecraft according to another embodiment of the present disclosure.

FIG. 6 shows a vector diagram of the back-drive control magnetic field of the back-drive braking control system of the spacecraft sheave mechanism according to an embodiment of the present disclosure.

Detailed ways

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numbers in the figures denote elements that have the same or similar functions. While various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present disclosure may be practiced without certain specific details. In some instances, methods, means, components and circuits well known to those skilled in the art have not been described in detail so as not to obscure the subject matter of the present disclosure.

In order to better understand the back-drive braking control method of the spacecraft sheave mechanism, the working principle of the back-drive braking control system of the spacecraft sheave mechanism is introduced first.

FIG. 3 shows a structural block diagram of a back-drive braking control system for a sheave mechanism of a spacecraft according to an embodiment of the present disclosure. As shown in Figure 3, the system may include: AD acquisition module, angle sensor module, driver module and FPGA module;

The AD acquisition module is used to collect the motor load current and send the motor load current to the FPGA module.

Among them, the main function of the AD acquisition module is to collect the load current (driving current) of the motor (as shown in Figure 1). Perform analog-to-digital conversion to obtain current data, and transmit the current data to the FPGA module.

An angle sensor module, configured to collect the angular velocity of the motor rotor, and send the angular velocity to the FPGA module.

The drive module is used to control the power supply and winding drive of the motor according to the motor power-on and power-off signal and the PWM signal received from the FPGA module, collect the motor load current through the sampling resistor, and send the motor load current to the AD acquisition module.

FIG. 4 shows a schematic block diagram of a driving module of a back-drive braking control system for a sheave mechanism of a spacecraft according to an embodiment of the present disclosure.

In an example, as shown in FIG. 4 , the driving module may include: an anti-reverse diode, a power supply switch, an energy storage capacitor, a power switch and a current sampling resistor;

Anti-reverse diode is used to prevent the transient high voltage of the driver module from being backflowed to the power supply bus of the detector.

The power supply switch is used to control the power-on and power-off of the drive module circuit. Among them, the power supply switch is a triode or a field effect transistor

The energy storage capacitor is used to filter the voltage fluctuation during the motor control process.

The power switch is used for on-off control according to the PWM signal sent by the FPGA module, and forms a rotating magnetic field in the stator winding of the motor to drive the motor to rotate.

In an example, as shown in Figure 4, six sets of power switches composed of field effect transistors and diodes can be included, and the on-off control is carried out according to the PWM signal sent by the FPGA, and the three-phase AC drive signal is combined to form a three-phase AC drive signal, which is used in the stator winding of the motor. A rotating magnetic field is formed to drive the motor to rotate.

The current sampling resistor is used to collect the motor load current and transmit the motor load current to the AD acquisition module.

The drive module controls the on-off of the internal power supply switch of the drive module by receiving the power-on and power-off signal sent by the FPGA, and at the same time receives the PWM signal sent by the FPGA, which is used to drive the power tube in the control module and generate the drive signal for the motor. Controls the power-up of the motor and the drive of the motor windings.

The FPGA module is used to control the motor back-drive braking state according to the motor load current, control the motor winding drive of the drive module according to the PWM signal obtained by processing the motor angular velocity, and output the motor power-on and power-off signal to the The drive module is used for the control of the motor power supply.

Among them, the FPGA module is the center of the reverse drive braking control system of the spacecraft sheave mechanism. It can mainly obtain the load current of the motor during operation through the AD acquisition module, and obtain the motor rotor movement angle data through the angle sensor.

In an example, controlling the motor back-drive braking state according to the motor load current may include: when the motor load current determines that the motor is in an overcurrent locked-rotor state, placing the motor in a back-drive braking state. According to the collected motor load current information, it is judged whether the motor is in an over-current locked-rotor state. When it is in an over-current locked-rotor state, the motor is placed in a reverse drive braking state to realize the overcurrent protection function of the FPGA module.

In an example, controlling the motor winding drive of the drive module according to the PWM signal obtained by processing the motor angular velocity may include: performing a differential operation on the motor angular velocity to obtain the motor running speed, and comparing the motor running speed with the expected running speed. The speed obtains the error information of the motor running speed, adjusts the PWM chopper duty cycle according to the error information, and combines the PWM chopper duty cycle and the PWM wave control sequence to generate a PWM signal to control the motor winding drive of the drive module.

The FPGA module obtains the motor running speed information by performing differential operation on the motor angle (motor rotor movement angle) data, and compares the motor running speed with the expected motor running angle to obtain the error information of the motor running speed, and adjusts the PWM chopper through the PI controller. duty cycle. The PWM signal is generated according to the PWM chopper duty cycle and the PWM wave control timing signal, and the PWM signal is output to the driving module to control the on-off control of the power switch of the driving module. Then, the closed-loop control of the motor running speed by the FPGA module is realized, and the back-drive control function of the FPGA module is realized.

The FPGA module also outputs a power-on and power-off control signal to the drive module to control the power-on and power off of the drive module. The FPGA module implements the overcurrent protection function and the reverse drive control function.

The back-drive braking control system of the spacecraft sheave mechanism of the present disclosure includes an AD acquisition module, an angle sensor module, a drive module and an FPGA module; the AD acquisition module is used to collect the motor load current and send the motor load current to the the FPGA module; the angle sensor module, used for collecting the angular velocity of the motor rotor, and sending the angular velocity to the FPGA module; the driving module, used for receiving the motor power-on and power-off signal and PWM signal of the FPGA The motor power supply and winding drive are controlled, the motor load current is collected by sampling the motor, and the motor load current is sent to the AD acquisition module; the FPGA module is used to control the motor back-drive braking state according to the motor load current, according to the The motor angular velocity is processed to obtain a PWM signal to control the motor winding drive of the drive module, and a motor power-on and power-off signal is output to the drive module for control of motor power supply. It can reduce the movement speed of the motor during the reverse drive process, effectively slow down the reverse drive speed during emergency shutdown, slowly release the elastic potential energy in the wire rope, and avoid damage to the control circuit, transmission system (transmission gear), etc.

When the motor is in the process of reverse drive braking, the rotor angle data of the motor is still collected in real time to calculate the running speed of the motor, and the reverse drive braking state of the motor is controlled according to the running speed of the motor.

FIG. 2 shows a flowchart of a method for controlling back-drive braking of a sheave mechanism of a spacecraft according to an embodiment of the present disclosure. The method can be applied to the reverse drive braking control system of the above-mentioned spacecraft sheave mechanism, and may include:

Step S1: preset the maximum and minimum values of the motor running speed.

The upper limit value (maximum value) and the lower limit value (minimum value) of the motor speed are preset. When the motor reverse drive running speed exceeds the motor speed upper limit value, the reverse drive braking control will automatically start. When the motor reverse drive running speed is lower than the lower limit value of the motor speed, the reverse drive braking control will automatically stop. Frequent starts or stops of backdrive braking control can be avoided.

Step S2: real-time detection of the motor reverse drive running speed, according to the relationship between the motor reverse drive running speed and the maximum value and the minimum value of the motor running speed, the FPGA module cyclically outputs PWM signals in different states to the drive module to The back-drive running speed of the motor is controlled to be between the maximum value and the minimum value of the motor running speed.

Among them, the maximum value and the minimum value of the motor running speed can also be referred to as the upper limit value and the lower limit value of the motor running speed, respectively.

The FPGA detects the motor reverse drive running speed in real time. When the motor reverse drive running speed is greater than the maximum value of the motor running speed or higher than the upper limit value of the motor running speed, the FPGA module outputs a PWM chopper signal to the drive module. The control vector signal is generated in the reverse driving direction of the motor, and the control vector signal prevents the motor reverse driving speed from increasing, reduces the motor reverse driving speed, and makes the motor reverse driving speed at the maximum and minimum values of the motor speed. between values.

When the motor reverse drive running speed is less than the minimum value of the motor running speed or lower than the lower limit value of the motor running speed, the FPGA module generates a PWM chopper signal in the shutdown state to the drive module, and the six power tubes of the drive module are all turned off. The elastic potential energy of the wire rope of the spacecraft sheave mechanism is continuously released, and the motor back-drive running speed is increased, so that the motor back-drive running speed is between the maximum value (upper limit) and the minimum value (lower limit) of the motor speed.

The hysteresis control of the motor's back-drive running speed through the FPGA module can control the motor's back-drive control cycle to start or stop, so that the motor's back-drive running speed is always controlled between the upper and lower limits of the motor speed, effectively avoiding the frequent back-drive braking control. start and stop.

[1] FIG. 5 shows a flowchart of a method for controlling back-drive braking of a sheave mechanism of a spacecraft according to another embodiment of the present disclosure. As shown in Figure 5, the method may further include:

Step S3: During the back-drive braking process, the power supply switch of the drive module is in an off state, and the back-drive control is performed by using the energy storage capacitor and the residual energy in the wire rope. When the residual energy is exhausted, the motor automatically Enter the shutdown state.

Since the power supply switch of the drive module is always off during the back-drive braking process, when the elastic potential energy in the wire rope of the spacecraft sheave mechanism is released, the external power supply system no longer provides energy for the drive module. The system uses the energy storage capacitor and the residual energy in the wire rope for back-drive control. After the elastic potential energy in the wire rope of the spacecraft sheave mechanism is dissipated, the energy is automatically controlled and dissipated, and the motor automatically enters the shutdown state, which can realize back-drive. Braking utilizes the residual energy in the system for braking control.

FIG. 6 shows a vector diagram of the back-drive control magnetic field of the back-drive braking control system of the spacecraft sheave mechanism according to an embodiment of the present disclosure.

As shown in Figure 6, the power supply switch PMOS of the drive module is turned off, and the PWM signal is used to fix the duty cycle open-loop mode, and the driving direction of the back-drive braking control is opposite to the back-drive direction.

The angle difference between the magnetic field vector generated in the motor stator winding and the rotor magnetic field vector in the backdrive braking control is 90°.

The control direction of the back-drive braking is the ramp unfolding direction of the sheave mechanism as shown in Figure 1, and the direction of the reverse driving force of the wire rope of the sheave mechanism is the ramp-retracting direction, then the torque generated by the back-drive braking control is opposite to the wire rope The driving moment forms a confrontation. When the power in the energy storage capacitor of the drive module gradually decreases, the back-drive braking control torque will also gradually decrease, the back-drive force is greater than the back-drive braking control torque, and the motor back-drive speed increases; the back-EMF increases, the current reverses Filled into the energy storage capacitor, the back-drive braking control torque will increase again. This is repeated until the release of the reverse driving torque of the wire rope is completed, and the power in the energy storage capacitor is also consumed.

The method for controlling the back-drive braking of the spacecraft sheave mechanism of the present disclosure is to set the maximum and minimum values of the motor running speed in advance; The relationship between the maximum value and the minimum value of the speed, the FPGA module cyclically outputs PWM signals in different states to the driving module, so as to control the motor back-drive running speed to be between the maximum value and the minimum value of the motor running speed. It can reduce the movement speed of the motor during the reverse drive process, effectively slow down the reverse drive speed during emergency shutdown, slowly release the elastic potential energy in the wire rope, and avoid damage to the control circuit, transmission system (transmission gear), etc.

Various embodiments of the present disclosure have been described above, and the foregoing descriptions are exemplary, not exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (5)

1. a method for back-drive braking control of a spacecraft sheave mechanism, is characterized in that, described method comprises: Pre-set the maximum and minimum values of the motor running speed; Real-time detection of the motor reverse drive operation speed, according to the relationship between the motor reverse drive operation speed and the maximum and minimum values of the motor operation speed, the FPGA module cyclically outputs PWM signals in different states to the drive module to control the motor reverse drive operation the speed is between the maximum and minimum operating speeds of the motor; According to the relationship between the motor reverse drive running speed and the maximum and minimum values of the motor running speed, the FPGA module outputs PWM signals in different states to the drive module to control the motor reverse drive running speed at the maximum value of the motor running speed. between the value and the minimum value, including: When the motor reverse drive running speed is greater than the maximum value of the motor running speed, the FPGA module outputs a PWM chopper signal to the drive module to generate a control signal opposite to the motor reverse drive operation, reducing the motor reverse drive running speed , so that the motor back-drive running speed is between the maximum value and the minimum value of the motor running speed; Or, when the motor back-drive running speed is less than the minimum value of the motor running speed, the FPGA module outputs a PWM chopper signal in a shutdown state to the drive module, and controls the power switch of the drive module to disconnect, and the wire rope Driven by the elastic potential energy, the reverse driving running speed of the motor increases, so that the reverse driving running speed of the motor is between the maximum value and the minimum value of the motor running speed; During the back-drive braking process, the power supply switch of the drive module is in an off state, and the back-drive control is performed by using the energy storage capacitor and the residual energy in the wire rope. When the residual energy is exhausted, the motor automatically enters a shutdown state. 2. a kind of spacecraft sheave mechanism anti-drive braking control system, it is characterized in that, described system applies the spacecraft sheave mechanism anti-drive braking control method described in claim 1, and described system comprises: AD acquisition module , angle sensor module, driver module and FPGA module; Wherein, the AD acquisition module is used to collect the motor load current and send the motor load current to the FPGA module; the angle sensor module, for collecting the angular velocity of the motor rotor, and sending the angular velocity to the FPGA module; The drive module is used to control the motor power supply and winding drive according to the received motor power-on and power-off signals and PWM signals of the FPGA, collect the motor load current through a sampling resistor, and send the motor load current to the AD collection module; The FPGA module is used to control the motor back-drive braking state according to the motor load current, control the motor winding drive of the drive module according to the PWM signal obtained by processing the motor angular velocity, and output the power on and off of the motor Signals to the drive module for motor power control. 3 . The back-drive braking control system according to claim 2 , wherein the control of the motor back-drive braking state according to the motor load current comprises: 3 . When the motor load current determines that the motor is in an over-current locked-rotor state, the motor is placed in a back-drive braking state. 4. The back-drive braking control system according to claim 2, wherein the control of the motor winding drive of the drive module is performed according to the PWM signal obtained by processing the motor angular velocity, comprising: Perform a differential operation on the motor angular velocity to obtain the motor running speed, compare the motor running speed and the expected running speed to obtain error information of the motor running speed, adjust the PWM chopper duty cycle according to the error information, and combine the PWM chopper duty cycle The ratio and PWM wave control sequence generate PWM signal to control the motor winding drive of the drive module. 5 . The back-drive braking control system according to claim 2 , wherein the drive module comprises: an anti-reverse diode, a power supply switch, an energy storage capacitor, a power switch and a current sampling resistor; 5 . Wherein, the anti-reverse diode is used to prevent the transient high voltage of the driving module from being reversed to the power supply bus of the detector; The power supply switch is used to control the power-on and power-off of the drive module circuit; The energy storage capacitor is used to filter the voltage fluctuation during the motor control process; The power switch is used for on-off control according to the PWM signal sent by the FPGA module, and a rotating magnetic field is formed in the stator winding of the motor to drive the motor to rotate; The current sampling resistor is used to collect the motor load current and transmit the motor load current to the AD acquisition module.

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