A full-electric brake control method with multiple actuation structures

Abstract

The application relates to the technical field of airplane brake systems, in particular to a multi-actuating-structure all-electric brake control method. The multi-actuating-structure all-electric brake control method is developed by adopting a software and hardware platform, the strategy is based on the software and hardware platform, the force response time and the control precision are improved, the brake efficiency is improved, the motor synchronous control is ensured, a reasonable degradation use can ensure normal use in the case of one fault of the all-electric brake system, and the all-electric brake system can be safe and reliable in the case of two faults, so that the reliability of the brake system operation is effectively improved, and the safety of airplane use is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft brake systems, in particular to a multi-actuation structure all-electric brake control method. BACKGROUND

[0002] With the prosperity of the domestic unmanned aerial vehicle market, the all-electric brake has the characteristics of simple system structure, light weight, easy maintenance, safety and the like compared with the traditional hydraulic brake, and at present, the most is 2-way motor control, which is only suitable for small unmanned aerial vehicles. For medium and large-sized high-speed unmanned aerial vehicles and even manned aircraft, there is no practical engineering experience for electric brakes, and at present, it is urgent to study the control strategy of the multi-actuation structure all-electric brake based on the brushless direct current motor, and to provide a safe and reliable electric brake control strategy. SUMMARY

[0003] In order to solve the problems in the prior art, the present application provides a multi-actuation structure all-electric brake control method to improve the safety and reliability of the aircraft. The following technical solutions are adopted:

[0004] A multi-actuation structure all-electric brake control method is developed by using a software and hardware platform, and the hardware platform processes:

[0005] a) power supply circuit design for DSP power supply, motor power supply, speed sensor power supply, force sensor power supply, etc.;

[0006] b) six motor independent driving circuit design;

[0007] c) speed acquisition circuit design;

[0008] d) motor Hall signal acquisition circuit design;

[0009] e) force acquisition circuit design;

[0010] f) communication circuit design.

[0011] The software platform processes:

[0012] a) initialization;

[0013] b) speed acquisition and filtering;

[0014] c) force acquisition and filtering;

[0015] d) motor control

[0016] e) anti-skid calculation;

[0017] f) PID calculation;

[0018] g) finding logic zero position;

[0019] h) instruction receiving and identification;

[0020] i) communication sending;

[0021] j) motor forward and reverse rotation count calculation.

[0022] Preferably, the full-electric brake control method hardware platform of the multi-acting structure comprises a power board, a control board, a driving board and a connecting bottom plate. The main function of the power board is to convert voltage and provide voltage. The main function of the control board is signal acquisition and signal processing. The main function of the connecting plate is to acquire pressure sensor signals, complete Hall signal, speed sensor signal and voltage transmission. The main function of the left and right driving boards is to control the driving circuit of the six motors.

[0023] Preferably, the rated voltage of the power board is +28VDC, has an anti-reverse connection function, considers electromagnetic compatibility and power supply compatibility and other related requirements, provides stable power supply for related circuits, and the power supply after secondary processing is mainly used for power supply of three-phase full-bridge driver, motor, pressure sensor, speed sensor, RS-422 bus transceiver driver, motor Hall, main control chip and the like.

[0024] Preferably, the control board needs to acquire signals such as pressure signal, speed signal, motor Hall signal and motor current signal, and output signals such as anti-skid control signal, motor forward and reverse rotation signal and PWM. The acquired signals are fed back to control the output control signal of the wheel to control the anti-skid brake.

[0025] Preferably, the driving board has two driving boards in total and is divided into left and right driving boards. The main function of the driving board is to control six motors, and the motor input current signal needs to be converted into a voltage signal which is collected by the ADC collection port in the main control chip. In order to ensure the safe and reliable operation of the motor, a brushless DC motor special driving circuit is selected to control the forward rotation, reverse rotation and stop rotation of the motor, so as to control the movement of the lead screw and output the required thrust.

[0026] Preferably, the main function of the connecting plate is to acquire pressure signals and Hall signals, realize signal transmission and conversion of the control board, the power board and the left and right driving boards. The pressure sensor outputs a 4-20mA current signal which needs to be converted into a voltage signal and collected by the ADC collection port in the main control chip. The motor Hall signal is collected by the CAP collection port in the main control chip after photoelectric isolation.

[0027] Preferably, the software mainly includes the following parts, including: initialization, RS-422 communication, pressure acquisition, zero control, speed acquisition, current acquisition, PID, anti-skid control, fault management and the like. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The control box hardware diagram of the application;

[0029] Figure 2 This is a logical schematic diagram of the present invention.

[0030] Beneficial effects

[0031] The multi-actuator all-electric braking control method provided by this invention is based on a software and hardware platform. It improves force response time and control accuracy, increases braking efficiency, ensures synchronous control of motors, and formulates reasonable degraded use to ensure normal operation in the all-electric braking system during a first failure and safe and reliable operation during a second failure. This effectively improves the reliability of the braking system and enhances the safety of aircraft operation. Detailed Implementation

[0032] The technical solution of the present invention will be further defined below with reference to specific embodiments, but the scope of protection is not limited to the description made.

[0033] Example 1

[0034] See appendix Figure 1 Appendix Figure 2 A multi-actuator all-electric braking control method, based on a software and hardware platform, achieves the following functions:

[0035] 1) Optimization of wheel speed signal acquisition

[0036] Two methods are planned for wheel speed acquisition hardware: one is to directly calculate the frequency of the wheel speed signal after waveform transformation and then send it to the DSP for frequency acquisition; the other is to send the voltage signal to the DSP after waveform transformation and then through a frequency-to-voltage conversion circuit. By acquiring these two types of signals, a reasonable algorithm will be developed to eliminate speed interference signals, enhance the anti-interference capability of speed signal acquisition, and ensure the accuracy of wheel speed signal acquisition.

[0037] 2) Multi-motor synchronous control

[0038] Due to the influence of the initial braking gap and the mechanical and electrical characteristics of each actuator, the torque response of each actuator will be different. A reasonable control strategy should be formulated to ensure the synchronization of the force response.

[0039] 3) Motor drive and anti-slip matching control

[0040] To address the characteristics of low power and high reduction ratio when using electric braking for low-voltage brushless DC motors, appropriate control parameters are formulated, and an anti-slip algorithm is used to design the matching between motor drive and anti-slip control, thereby improving the system's response and braking efficiency.

[0041] 4) Automatic return strategy without a separate Hall sensor for positioning

[0042] The initial brake gap and return control of the electric brake project are positioned by a Hall sensor at present, and the Hall sensor is inconvenient to install and maintain due to space limitation, and positioning deviation is large. The Hall sensor is cancelled in the application, the number of clockwise / anticlockwise rotations of the motor is calculated through the collection of the Hall signal of the motor itself, and the automatic return control strategy is realized.

[0043] 5) Fault degradation motor control strategy

[0044] The application controls at least six motors, formulates a reasonable control strategy, ensures that the system can brake normally after the control of one motor fails, ensures the safety of the system after the control of more than two motors fails, and further improves the reliability of the electric brake.

[0045] 6) Modular design of core control algorithm

[0046] The core algorithm such as the PID control algorithm of the motor and the anti-skid algorithm is modularly designed and encapsulated in the form of a static library, so as to facilitate software reuse.

[0047] 7) Development of upper computer software

[0048] The upper computer software is needed during the test to simulate the function of the flight control computer, send instructions to the software and hardware platform, store the key information such as force signals, speed signals and anti-skid signals fed back by the software platform. LabWindowsCVI software is prepared to be used for the development of the upper computer.

[0049] Through the above functions, the force response time and control accuracy are improved, the brake efficiency is improved, the synchronous control of the motor is ensured, and a reasonable degradation use can ensure normal use in the case of a fault of the full-electric brake system, and can be safe and reliable in the case of a secondary fault.

[0050] Specifically, the hardware assembly is a brake control box, which mainly consists of a shell, a cover plate, a power board, a control board, a driving board, a connecting bottom plate, a baffle, a socket, a plug and tail accessories, etc. The main function of the power board is to convert voltage and provide voltage. The main function of the control board is signal acquisition and signal processing. The main function of the connecting plate is to acquire the signal of the pressure sensor, complete the Hall signal, the speed sensor signal and voltage transmission. The main function of the left and right driving boards is to control the driving circuit of the six motors.

[0051] Specifically, the software is brake control box software, mainly including the following parts, including: initialization, RS-422 communication, pressure acquisition, zero control, speed acquisition, current acquisition, PID, anti-skid control, fault management, etc. Among them, the initialization module completes the initialization of the DSP register and global variable; RS-422 communication is mainly used for the interaction of the control box and the host computer and the communication inside the control box; pressure acquisition realizes the acquisition of pressure signal, which is used for PID calculation and periodic BIT detection; the initial gap of the brake device is used as the logical zero of the motor, and the motor is controlled to be in the logical zero after the brake control box is powered on; the speed acquisition identifies the frequency of the wheel speed sensor output signal through the CAP port of the DSP, and obtains the wheel speed after conversion, or acquires the converted wheel speed sensor output signal through the AD port of the DSP; current acquisition acquires the current in the working process of the motor in real time, and judges the current value to prevent the motor from being overloaded; PID calculation is calculated according to the brake amount and the collected thrust; motor control outputs the corresponding PWM signal and high and low level according to the result of PID calculation.

[0052] The full-electric brake control method of the multi-actuating structure of the embodiment is developed by using software and hardware platforms. The method improves the force response time and control precision, improves the brake efficiency, ensures the synchronous control of the motor, formulates a reasonable degradation use, ensures normal use in the case of a full-electric brake system failure, and ensures safety and reliability in the case of a secondary failure, thereby effectively improving the reliability of the brake system operation and effectively improving the safety of the aircraft use.

Claims

1. A multi-actuator all-electric braking control method, based on a software and hardware platform, characterized in that, Hardware platform processing: 1) Power supply circuit design; 2) Design of independent drive circuits for six motors; 3) Design of speed acquisition circuit; 4) Design of motor Hall signal acquisition circuit; 5) Design of pressure acquisition circuit; 6) Design of communication circuit; The hardware platform is a brake control box, which mainly consists of a shell, cover plate, power board, control board, drive board, connecting base plate, baffle, socket, plug and tail accessories. The power board is used for voltage conversion, the control board is used for signal acquisition and signal processing, and the left and right drive boards are used to control the six motors. The software platform includes: initialization, RS-422 communication, pressure acquisition, zero-position control, speed acquisition, current acquisition, PID calculation, anti-slip control, and fault management. Initialization completes the initialization of DSP registers and global variables; RS-422 communication is mainly used for interaction between the control box and the host computer, as well as internal communication within the control box; pressure acquisition collects pressure signals for PID calculation and periodic bit detection; the initial gap of the braking device serves as the logical zero position of the motor, and the motor is controlled to be in the logical zero position after the brake control box is powered on; speed acquisition identifies the frequency of the wheel speed sensor output signal through the DSP's CAP port and converts it to obtain the wheel speed, or acquires the converted wheel speed sensor output signal through the DSP's AD port; current acquisition collects the current during the motor's operation in real time and judges the current value to prevent motor overload; PID calculation is performed based on the braking amount and the acquired pressure; motor control outputs the corresponding PWM signal and high / low level according to the PID calculation result.

2. The multi-actuator all-electric braking control method according to claim 1, characterized in that: The speed acquisition circuit includes wheel speed acquisition. The wheel speed acquisition method includes: the wheel speed signal is transformed into a waveform and then directly acquired by the DSP for frequency calculation, or the wheel speed signal is transformed into a waveform and then sent to the DSP as a voltage signal through a frequency-to-voltage conversion circuit. By acquiring both types of signals, a reasonable algorithm is formulated to eliminate speed interference signals, enhance the anti-interference capability of speed signal acquisition, and ensure the accuracy of wheel speed signal acquisition.

3. The multi-actuator all-electric braking control method according to claim 1, characterized in that: Motor control includes multi-motor synchronous control and fault-degrading motor control strategies. Specifically, multi-motor synchronous control is affected by the initial braking gap and the mechanical and electrical characteristics of each actuator, resulting in different torque responses for each actuator. By studying and formulating control strategies, the synchronicity of force responses is ensured. The fault-degrading motor control strategy controls at least 6 motors. If one motor fails, the system can still brake normally, and if two or more motors fail, the system can be kept safe.

4. The multi-actuator all-electric braking control method according to claim 1, characterized in that: The anti-slip control specifically involves: for low-power and high-reduction ratio applications of electric brakes on low-voltage brushless DC motors, setting control parameters and using an anti-slip algorithm to design the matching between motor drive and anti-slip control.

5. The multi-actuator all-electric braking control method according to claim 1, characterized in that: The PID calculation specifically involves: calculating based on the braking amount and the collected pressure, correcting the output pressure, and controlling the forward and reverse rotation signals of the motor; the PID control algorithm is modularly designed and encapsulated into a static library.

6. The multi-actuator all-electric braking control method according to claim 1, characterized in that: The logic zero position is achieved by collecting the Hall signals inherent in the motor itself, calculating the number of forward / reverse rotations of the motor, and implementing an automatic return-to-position control strategy.

7. The multi-actuator all-electric braking control method according to claim 1, characterized in that: The power supply circuit design includes: DSP power supply, motor power supply, speed sensor power supply, and force sensor power supply.

Images