Multi-actuation structure all-electric brake control method

Abstract

The invention relates to the technical field of aircraft brake systems, in particular to a multi-actuation structure all-electric brake control method. By adopting software and hardware platform development, the provided multi-actuation structure all-electric brake control method and strategy are based on the software and hardware platform, the force response time is prolonged, the control precision is improved, the brake efficiency is improved, synchronous control of a motor is ensured, reasonable degradation use is formulated, and normal use can be ensured when an all-electric brake system breaks down once; and the secondary fault can be safe and reliable, so that the operation reliability of the brake system is effectively improved, and the use safety of an airplane is effectively improved.

Description

Technical Field

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

[0002] With the prosperity of the domestic UAV market, all-electric brakes have the characteristics of simple system structure, light weight, easy maintenance and high safety compared to traditional hydraulic brakes. Currently, the most common ones are 2-way motor control, which is only suitable for small UAVs. There is no actual engineering experience for electric brakes on medium and large high-speed UAVs or even manned aircraft. At present, there is an urgent need to study the control strategy of electric brakes based on multi-actuation structures of brushless DC motors to provide safe and reliable electric brake control strategies. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the present invention proposes a multi-actuation structure all-electric brake control method to improve the safety and reliability of aircraft use. The following technical solutions are adopted: A multi-actuation structure all-electric brake control method is developed using a software and hardware platform. The hardware platform processes: a) Design of power supply circuits for DSP power supply, motor power supply, speed sensor power supply, force sensor power supply, etc.; b) Design of independent drive circuits for six motors; c) Speed ​​acquisition circuit design; d) Design of motor Hall signal acquisition circuit; e) Design of force collection circuit; f) Communication circuit design.

[0004] Software platform processing: a) Initialization; b) Speed ​​acquisition and filtering; c) force acquisition and filtering; d) Motor control e) Anti-slip calculation; f) PID calculation; g) Find the logical zero position; h) Command reception and recognition; i) Sending of communications; j) Calculate the number of forward and reverse revolutions of the motor.

[0005] Preferably, the hardware platform of the multi-actuation structure all-electric brake control method includes a power board, a control board, a drive board, and a connection base board; the power board mainly functions to convert voltage and provide voltage. The control board mainly functions to collect and process signals; the connection board mainly functions to collect pressure sensor signals, complete Hall signals, speed sensor signals, and voltage transmission. The left and right drive boards mainly function to control the drive circuits of the six motors.

[0006] Preferably, the power board has a rated voltage of +28VDC, has an anti-reverse connection function, takes into account relevant requirements such as electromagnetic compatibility and power supply compatibility, and provides a stable power supply for related circuits. The power supply after secondary processing is mainly for: three-phase full-bridge driver, motor, pressure sensor, speed sensor, RS-422 bus transceiver driver, motor Hall, main control chip, etc.

[0007] Preferably, the control panel needs to collect the following signals: pressure signal, speed signal, motor Hall signal, motor current signal, and output signals: anti-skid control signal, motor forward and reverse signal, PWM. The wheel output control signal is used for anti-skid brake control based on the feedback of the collected signals.

[0008] Preferably, there are two drive boards in total, which are divided into left and right drives. The main function of the drive board is to control 6 motors, and the motor input current signal needs to be converted into a voltage signal for collection by the ADC acquisition port in the main control chip. In order to ensure the safe and reliable operation of the motor, a brushless DC motor dedicated drive circuit is selected to control the forward, reverse and stop rotation of the motor, thereby controlling the movement of the lead screw and outputting a thrust that meets the requirements.

[0009] Preferably, the main function of the connecting board is to collect pressure signals and Hall signals, and realize signal transmission and conversion between the control board, power board, and left and right drive boards. The pressure sensor outputs a 4-20mA current signal, which needs to be converted into a voltage signal and collected by the ADC acquisition port in the main control chip. The motor Hall signal is collected by the CAP acquisition port in the main control chip after photoelectric isolation.

[0010] Preferably, the software mainly includes the following parts, including: initialization, RS-422 communication, pressure acquisition, zero position control, speed acquisition, current acquisition, PID, anti-slip control, fault management, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is the hardware diagram of the control box of the present invention; Figure 2 It is a logical schematic diagram of the present invention.

[0012] Beneficial Effects The multi-actuation structure all-electric brake control method provided by the present invention has a strategy based on the software and hardware platform, which improves the force response time and control accuracy, improves the braking efficiency, ensures the synchronous control of the motor, and formulates reasonable degradation use to ensure normal use in the event of a primary failure in the all-electric brake system, and safe and reliable secondary failures, thereby effectively improving the reliability of the brake system operation and effectively improving the safety of aircraft use. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is further defined below in conjunction with specific implementation methods, but the scope of protection required is not limited to the description.

[0014] Example 1 See attached Figure 1 , Attachment Figure 2 , a multi-actuation structure all-electric brake control method, based on the software and hardware platform to achieve the following functions: 1) Wheel speed signal collection optimization Two methods are planned to be used in the wheel speed acquisition hardware. One is to directly collect the wheel speed signal to DSP for frequency calculation after the waveform is transformed. The other is to collect the voltage signal to DSP after the waveform is transformed through the frequency-voltage conversion circuit. Through the two signal collections, a reasonable algorithm is formulated to eliminate the speed interference signal, enhance the anti-interference ability of speed signal collection, and ensure the accuracy of wheel speed signal collection.

[0015] 2)Multi-motor synchronous control Affected by the initial brake gap, the mechanical and electrical characteristics of each actuator, the torque response of each actuator is different. A reasonable control strategy is formulated to ensure the synchronization of force response.

[0016] 3) Motor drive and anti-skid matching control In view of the characteristics of low-voltage brushless DC motors such as low power and high reduction ratio when using electric brakes, appropriate control parameters are formulated, and the anti-skid algorithm is used to design the matching between motor drive and anti-skid control to improve the system response and braking efficiency.

[0017] 4) Automatic return strategy without separate Hall sensor positioning At present, the initial brake clearance and return control of electric brake projects are both positioned by Hall sensors. Due to space limitations, the Hall sensors are inconvenient to install, maintain, and have large positioning deviations. The present invention intends to eliminate the Hall sensor, collect the Hall signal of the motor itself, calculate the number of forward / reverse rotations of the motor, and implement the automatic return control strategy.

[0018] 5) Fault-degraded motor control strategy The present invention controls at least six motors and formulates a reasonable control strategy to ensure that the system can brake normally after one motor fails to be controlled. If two or more motors fail to be controlled, the system safety is guaranteed and the reliability of the electric brake is further improved.

[0019] 6) Modular design of core control algorithm The core algorithms such as the motor's PID control algorithm and anti-skid algorithm are modularly designed and packaged into a static library to facilitate software reuse.

[0020] 7) Host computer software development When conducting the test, the host computer software is needed to simulate the functions of the flight control computer, send instructions to the software and hardware platform, and store the key information such as force signals, speed signals, anti-skid signals, etc. fed back by the software platform. LabWindowsCVI software is planned to be used for host computer development.

[0021] Through the above functions, the force response time and control accuracy are improved, the braking efficiency is improved, the synchronous control of the motor is ensured, and reasonable degradation is formulated to ensure normal use in the event of a primary failure in the all-electric brake system, and safe and reliable use in the event of a secondary failure.

[0022] Specifically, the hardware assembly is a brake control box, which is mainly composed of a housing, a cover plate, a power board, a control board, a drive board, a connection base plate, a baffle, a socket, a plug and tail accessories. The power board mainly functions to convert voltage and provide voltage. The control board mainly functions to collect and process signals. The connection board mainly functions to collect pressure sensor signals, complete Hall signals, speed sensor signals, and voltage transmission. The left and right drive boards mainly function to control the drive circuits of the six motors.

[0023] Specifically, the software is a brake control box software, which mainly includes the following parts, including: initialization, RS-422 communication, pressure acquisition, zero position control, speed acquisition, current acquisition, PID, anti-skid control, fault management, etc. Among them, the initialization module completes the initialization of DSP registers and global variables; RS-422 communication is mainly used for the interaction between the control box and the host computer and the communication inside the control box; pressure acquisition realizes the acquisition of pressure signals for PID calculation and periodic BIT detection; the initial gap of the brake device is used as the logical zero position of the motor, and the brake control box controls the motor to be in the logical zero position after power-on; 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 collects the converted wheel speed sensor output signal through the AD port of the DSP; current acquisition collects the current of the motor working process in real time, and judges the current value to prevent the motor from overloading; PID calculation is calculated according to the braking amount and the collected thrust; motor control outputs the corresponding PWM signal and high and low levels according to the result of PID calculation.

[0024] A multi-actuation structure all-electric brake control method of the present embodiment is developed using a software and hardware platform. The method improves force response time and control accuracy, improves braking efficiency, ensures synchronous control of the motor, and formulates reasonable degradation use to ensure normal use in the event of a primary failure in the all-electric brake system, and safe and reliable secondary failures, thereby effectively improving the reliability of the brake system operation and effectively improving the safety of aircraft use.

Claims

1. A multi-actuation structure all-electric brake control method, based on software and hardware platforms, characterized in that: Hardware platform processing: 1) power circuit design; 2) Design of six independent motor drive circuits; 3) Design of speed acquisition circuit, 4) Design of motor Hall signal acquisition circuit; 5) Design of force acquisition circuit; 6) Design of communication circuit; Software platform processing: 1) Initialization; 2) Speed ​​acquisition and filtering; 3) Force acquisition and filtering; 4) Motor control; 5) Anti-skid calculation; 6) PID calculation; 7) Finding the logical zero position; 8) Receiving and identifying instructions; 9) Sending communications; 10) Calculating the number of forward and reverse rotations of the motor.

2. The multi-actuation structure all-electric brake control method according to claim 1, characterized in that: The speed acquisition circuit includes wheel speed acquisition, and the wheel speed acquisition method includes: the wheel speed signal is sent to DSP for acquisition and direct frequency calculation after waveform transformation, or the voltage signal is sent to DSP for acquisition through frequency-voltage conversion circuit after waveform transformation. Through the two types of signal acquisition, a reasonable algorithm is formulated to eliminate speed interference signals, enhance the anti-interference ability of speed signal acquisition, and ensure the accuracy of wheel speed signal acquisition.

3. The multi-actuation structure all-electric brake control method according to claim 1, characterized in that: The motor control includes multi-motor synchronous control and fault-degraded motor control strategy; specifically: multi-motor synchronous control is affected by the initial braking gap, the mechanical and electrical characteristics of each actuator itself, and ultimately the torque response of each actuator is different. Through research and development of control strategies, the synchronization of force responses is guaranteed; the fault-degraded motor control strategy controls at least 6 motors, and after the control of one motor fails, it ensures that the system can brake normally, and ensures system safety when the control of more than two motors fails.

4. The multi-actuation structure all-electric brake control method according to claim 1, characterized in that: The anti-skid calculation is specifically as follows: according to the characteristics of low power and high reduction ratio when the low-voltage brushless DC motor is applied with electric brake, control parameters are formulated, and the matching design of motor drive and anti-skid control is performed using the anti-skid algorithm.

5. The multi-actuation structure all-electric brake control method according to claim 1, characterized in that: The PID calculation is specifically as follows: calculating according to the braking amount and the collected thrust, correcting the output pressure and controlling the forward and reverse rotation signal of the motor; modularizing the PID control algorithm and encapsulating it into a static library.

6. The multi-actuation structure all-electric brake control method according to claim 1, characterized in that: The logic zero position is found by collecting the Hall signal of the motor itself, calculating the number of forward / reverse rotations of the motor, and implementing the automatic return control strategy.

7. The multi-actuation structure all-electric brake 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.

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