Electric brake based on normal stress actuator and electromechanical actuator and control method

Abstract

The invention relates to an electric brake based on a normal stress actuator and an electromechanical actuator and a control method. The electric brake comprises the normal stress actuator, a brake disc, the electromechanical actuator, a brake controller, a servo controller and a current controller. And the brake controller selects a corresponding working mode according to the current brake pressure, the target brake pressure, the warning brake pressure and the basic brake pressure, so that the pressure of the normal stress actuator and the electromechanical actuator on the brake disc is controlled, accurate braking and disturbance suppression of the airplane wheel are realized, and the method is used for executing the process. The normal stress actuator and the electromechanical actuator extrude the brake disc to conduct braking, due to the fact that the normal stress actuator achieves pressure control by changing the magnitude of current, regulation and control are more accurate, the brake is suitable for fine adjustment, and the brake controller firstly controls the electromechanical actuator to adjust the pressure to the approximate range and then controls the actuator to conduct fine adjustment.

Description

Technical Field

[0001] The present invention relates to the technical field of electric brakes, and more particularly to an electric brake and a control method based on a normal stress actuator and an electromechanical actuator. Background Art

[0002] In an aircraft electric brake system, the electromechanical actuator has gradually replaced the hydraulic actuator and the electro-hydraulic actuator as a new linear actuator due to its advantages such as compact structure and good maintainability. It mainly consists of a motor and a mechanical actuator (a reduction gear train and a ball screw pair). During the braking process, the piston of the electromechanical actuator extends to squeeze the brake disc, forming a braking pressure, and the braking pressure is proportional to the braking force. However, due to the very high stiffness of the brake disc, during the process of the electromechanical actuator driving the piston to press the brake disc, even a very slight change in the piston displacement will cause a very large change in the braking pressure. Due to the limited position control accuracy of the electromechanical actuator, the control accuracy of the braking pressure is not high. At the same time, during the braking process, the brake disc is prone to frictional vibration. Due to the limited control bandwidth of the electromechanical actuator, it is unable to follow the vibration and adjust the piston position in a timely manner, resulting in a large fluctuation in the braking pressure and affecting the stability of the braking force.

[0003] The invention patent with the publication number CN118953674A discloses a closed-loop control method for braking pressure, including the following steps: Step 1, according to the technical requirements of the wheel brake system, calculate and set the corresponding curve of the output voltage of the command sensor and the braking pressure; Step 2, set the median range of the dead zone current of the hydraulic servo to be 0.8 - 1.2 mA, and the median range of the electronic zero voltage of the command sensor to be 0.78 - 0.86 mV, which is the starting point of the corresponding curve of the output voltage of the command sensor and the braking pressure; Step 3, set the initial conditions for entering the pressure closed-loop, etc. This invention can ensure the stability of the braking pressure output, but it cannot accurately regulate the pressure and does not show how to make it return to normal when the pressure fluctuates greatly.

[0004] Therefore, it is an urgent problem to be solved at present to provide an electric brake and a control method that can accurately regulate the pressure. Summary of the Invention

[0005] The purpose of the present invention is to provide an electric brake and a control method based on a normal stress actuator and an electromechanical actuator to overcome the deficiencies of the above-mentioned existing technologies.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to one aspect of the present invention, an electric brake based on a normal stress actuator and an electromechanical actuator is provided. The electric brake is used for the wheels of an aircraft. The electric brake includes a normal stress actuator, a brake disc, an electromechanical actuator, a brake controller, a servo controller, and a current controller. The normal stress actuator and the electromechanical actuator are respectively installed on both sides of the brake disc symmetrically. The brake controller is respectively connected to the servo controller and the current controller. The servo controller is connected to the electromechanical actuator. The current controller is connected to the normal stress actuator. The electromechanical actuator detects the current brake pressure;

[0008] The brake controller selects a corresponding working mode according to the current brake pressure, the target brake pressure, the warning brake pressure, and the basic brake pressure, so as to control the pressure of the normal stress actuator and the electromechanical actuator on the brake disc, and realize the precise braking of the wheel and the suppression of disturbances.

[0009] As a preferred technical solution, the electric brake further includes a pressing disc and a pressure-bearing disc. The electromechanical actuator is installed on the brake disc through the pressing disc. The normal stress actuator is installed on the brake disc through the pressure-bearing disc.

[0010] As a preferred technical solution, both the electromechanical actuator and the normal stress actuator include an output shaft. The output shaft of the electromechanical actuator is connected to the pressing disc. The output shaft of the normal stress actuator is connected to the pressure-bearing disc.

[0011] As a preferred technical solution, the electromechanical actuator further includes a force sensor. The force sensor is installed on the output shaft of the electromechanical actuator.

[0012] As a preferred technical solution, the electric brake further includes a brake housing. The brake disc includes a static disc and a moving disc. The moving disc is connected to the wheel. The static disc is fixed to the brake housing.

[0013] According to another aspect of the present invention, a control method for an electric brake based on a normal stress actuator and an electromechanical actuator as described above is provided. The method selects a corresponding working mode according to the current brake pressure, the target brake pressure, the warning brake pressure, and the basic brake pressure, and performs precise braking or disturbance suppression. The working mode includes three modes;

[0014] Mode 1: The electromechanical actuator and the normal stress electromagnetic actuator work together. The brake controller sends instructions to the current control electrical appliance and the servo controller at the same time. The electromechanical actuator and the normal stress electromagnetic actuator are both in a working state, and the brake disc is squeezed;

[0015] Mode 2: The electro-mechanical actuator works independently. The brake controller sends an instruction to the servo controller, and the electro-mechanical actuator is in the working state to squeeze the brake disc; the coil of the normal stress electromagnetic brake is de-energized;

[0016] Mode 3: The normal stress electromagnetic actuator works independently. The brake controller sends an instruction to the current controller, the electro-mechanical actuator works in the locked mode, and the normal stress electromagnetic brake is in the working state to squeeze the brake disc.

[0017] As a preferred technical solution, the braking has the following process:

[0018] In the braking process, first select Mode 2. The brake controller sends a position control instruction to the servo controller, and the servo controller controls the output shaft of the electro-mechanical actuator to move and press the brake disc;

[0019] Subsequently, adjust to Mode 3. After the output shaft of the electro-mechanical actuator moves in place, the electro-mechanical actuator stops. The brake controller sends an instruction to the current controller, and the current controller adjusts the coil current according to the instruction to press the brake disc.

[0020] As a preferred technical solution, the disturbance suppression has the following process:

[0021] S1. If the current brake pressure fluctuates within the range of the basic brake pressure and the warning brake pressure, then select Mode 3;

[0022] S11. In Mode 3, if the brake pressure is greater than the target brake pressure, then reduce the coil current of the normal application actuator, and the output shaft of the normal application actuator releases the brake disc; if the brake pressure is less than the target brake pressure, then increase the coil current of the normal application actuator, and the output shaft of the normal application actuator squeezes the brake disc.

[0023] As a preferred technical solution, the disturbance suppression further includes:

[0024] If the current brake pressure is lower than the basic brake pressure, then select Mode 1 until the current brake pressure returns to the range of the basic brake pressure and the warning brake pressure.

[0025] As a preferred technical solution, the disturbance suppression further includes:

[0026] If the current brake pressure is higher than the warning brake pressure, then select Mode 1 until the current brake pressure returns to the range of the basic brake pressure and the warning brake pressure.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention brakes by squeezing the brake disc with a normal stress actuator and an electromechanical actuator. Since the normal stress actuator controls the pressure by changing the magnitude of the current, the regulation is more precise and suitable for fine adjustment. The brake controller first controls the electromechanical actuator to adjust the pressure to a rough range, and then controls the actuator for fine adjustment.

[0029] 2. The present invention is divided into three working modes according to the target brake pressure, warning brake pressure, and basic brake pressure. Select a suitable mode according to the current brake pressure to adjust the pressure, so that the brake pressure is always consistent with the target brake pressure, ensuring stable braking power.

[0030] 3. The target brake pressure, warning brake pressure, and basic brake pressure of the present invention can all be set according to the actual situation. Select the corresponding mode to adjust the pressure according to the current brake pressure.

[0031] 4. A force sensor is provided on the output shaft of the electromechanical actuator of the present invention. When the output shaft squeezes the brake disc, the force sensor can better detect the pressure.

[0032] 5. The normal stress actuator and the electromechanical actuator of the present invention are symmetrically installed on both sides of the brake disc, facilitating squeezing from both sides. The output shafts of the normal stress actuator and the electromechanical actuator are on the same axis, ensuring structural safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 is a schematic sectional view of the overall structure of the present invention;

[0035] Figure 3 is a schematic sectional view of the electromechanical actuator of the present invention;

[0036] Figure 4 is a schematic sectional view of the normal stress electromagnetic actuator of the present invention;

[0037] Figure 5 is a schematic diagram of the structure of the static disc of the present invention;

[0038] Figure 6 is a schematic diagram of the structure of the moving disc of the present invention;

[0039] Figure 7 is a schematic diagram of the structure of the brake housing of the present invention;

[0040] Figure 8 is a schematic diagram of the structure of the actuator seat of the present invention;

[0041] Figure 9 is a schematic diagram of the structure of the outer cylinder of the present invention;

[0042] Figure 10 Schematic diagram of the piston structure of the present invention;

[0043] Figure 11 Schematic diagram of the output shaft structure of the present invention;

[0044] Figure 12 Schematic diagram of the control connection of the present invention;

[0045] Figure 13 Schematic diagram of the control process of the present invention.

[0046] 1. Normal stress actuator, 2. Static disk, 3. Moving disk, 4. Compression disk, 5. Electromechanical actuator, 6. Actuator seat assembly, 7. Pressure-bearing disk, 8. Brake housing, 9. Base cover, 10. Low-speed gear, 11. Locking nut, 12. Base, 13. Lower end cover, 14. Outer cylinder, 15. Piston, 16. Upper end cover, 17. Output shaft, 18. Force sensor, 19. High-speed gear, 20. Motor, 21. Bearing pressing plate, 22. Bearing set, 23. Lead screw nut, 24. Lead screw shaft, 25. Guide ring, 26-1. Stator housing, 26-2. Stator housing, 27-1. Stator, 27-2. Stator, 28-1. Coil, 28-2. Coil, 29. Guide ring, 30. Output shaft, 31. Round nut, 32. Guide ring, 33. Permanent magnet ring, 34. Rotor armature. Specific embodiments

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Due to the low control accuracy of the brake pressure of the aircraft electro-brake and the easy occurrence of brake pressure fluctuations due to vibration interference; based on the advantages of the normal stress electromagnetic actuator such as compact structure, fast response, and high force density, the present invention integrates the normal stress electromagnetic actuator into the electro-brake, enabling the normal stress electromagnetic actuator and the electromechanical actuator to jointly adjust the brake pressure; the electromechanical actuator is responsible for macroscopic movement to achieve rough adjustment of the brake pressure; the normal stress electromagnetic actuator is responsible for micro-displacement and disturbance response, and uses its high displacement accuracy and fast response characteristics to achieve precise adjustment of the brake pressure. Through the coordinated work of the normal stress electromagnetic actuator and the electromechanical actuator, precise and stable control of the brake pressure is achieved.

[0049] The present invention provides an electric brake and a control method based on a normal stress actuator and an electromechanical actuator; the present invention brakes by squeezing the brake disc with the normal stress actuator and the electromechanical actuator. Since the normal stress actuator controls the pressure by changing the magnitude of the current, the regulation is more precise and suitable for fine adjustment. The brake controller first controls the electromechanical actuator to adjust the pressure to a rough range, and then controls the actuator for fine adjustment. The present invention is divided into three working modes according to the target brake pressure, the warning brake pressure, and the basic brake pressure, and selects a suitable mode for pressure adjustment according to the current brake pressure, so that the brake pressure is always consistent with the target brake pressure, ensuring stable braking power. The target brake pressure, the warning brake pressure, and the basic brake pressure of the present invention can all be set according to the actual situation, and the pressure is adjusted by selecting the corresponding mode according to the current brake pressure. A force sensor is provided on the output shaft of the electromechanical actuator of the present invention. When the output shaft squeezes the brake disc, the force sensor can better detect the pressure. The normal stress actuator and the electromechanical actuator of the present invention are symmetrically installed on both sides of the brake disc, which is convenient for squeezing from both sides. The output shafts of the normal stress actuator and the electromechanical actuator are on the same axis, ensuring structural safety.

[0050] Embodiment 1

[0051] As Figure 1-11 described, an electric brake based on a normal stress actuator and an electromechanical actuator, the electric brake is used for the wheels of an aircraft, and the electric brake includes a normal stress actuator 1, a brake disc, an electromechanical actuator 5, a brake controller, a servo controller, and a current controller. The normal stress actuator 1 and the electromechanical actuator 5 are respectively installed on both sides of the brake disc and are symmetric. The brake controller is respectively connected to the servo controller and the current controller. The servo controller is connected to the electromechanical actuator (5), and the current controller is connected to the normal stress actuator 1. The electromechanical actuator 5 detects the current brake pressure;

[0052] The brake controller selects a corresponding working mode according to the current brake pressure, the target brake pressure, the warning brake pressure, and the basic brake pressure, so as to control the pressure of the normal stress actuator 1 and the electromechanical actuator 5 on the brake disc, and achieve precise braking and disturbance suppression of the wheels.

[0053] The electric brake further includes a pressing disc 4 and a bearing disc 7. The electromechanical actuator 5 is installed on the brake disc through the pressing disc 4, and the normal stress actuator 1 is installed on the brake disc through the bearing disc 7.

[0054] Both the electromechanical actuator 5 and the normal stress actuator 1 include output shafts. The output shaft of the electromechanical actuator 5 is connected to the pressing disc 4, and the output shaft of the normal stress actuator 1 is connected to the bearing disc 7.

[0055] The electro-mechanical actuator 5 further includes a force sensor 18, and the force sensor 18 is mounted on the output shaft of the electro-mechanical actuator 5.

[0056] The electric brake further includes a brake housing 8. The brake disc includes a stationary disc 2 and a moving disc 3. The moving disc 3 is connected to the wheel, and the stationary disc 2 is fixed to the brake housing 8.

[0057] In this embodiment, the brake disc includes multiple disc-shaped brake discs, which are divided into a stationary disc 2 and a moving disc 3. The stationary disc 2 is fixed to the brake housing 8, and the moving disc 3 is fixedly connected to the wheel and rotates with the wheel. During braking, the output shaft of the normal stress electromagnetic actuator 1 or the electro-mechanical actuator 5 presses the brake disc, generating a braking pressure between the moving disc 3 and the stationary disc 2, and then generating a frictional force, which decelerates the wheel and finally stops it from rotating. The normal stress electromagnetic actuator 1 and the electro-mechanical actuator 5 are mounted on both sides of the brake housing 8 and can both press the brake disc. The normal stress electromagnetic actuator 1 is connected to the brake housing 8 by bolts. The electro-mechanical actuator 5 is connected to the actuator seat assembly 6 by bolts, and the actuator seat assembly 6 is fixed to the brake housing 8 by bolts. The output shafts of the normal stress electromagnetic actuator 1 and the electro-mechanical actuator 5 both point to the brake disc. When executing a braking command, the internal motor of the electro-mechanical actuator 5 drives the ball screw to drive the actuator piston to move outwards, thereby pressing the compression disc 4 of the brake, and then pressing the stationary disc and the moving disc. When executing a braking command, the internal coil of the normal stress electromagnetic actuator 1 is energized, and the moving armature is stressed and drives the output shaft to move outwards, thereby pressing the pressure-bearing disc 7, and then pressing the stationary disc 2 and the moving disc 3.

[0058] During the entire braking process, both the normal stress electromagnetic actuator 1 and the electro-mechanical actuator 5 can press the brake disc to generate a braking pressure. Among them, the electro-mechanical actuator 5 has a longer stroke, but its motion accuracy is lower than that of the normal stress electromagnetic actuator 1. The electro-mechanical actuator 5 is responsible for large-range movement and generating a basic braking pressure. The normal stress actuator 1 has a fast response and high motion accuracy. After the electro-mechanical actuator 5 establishes a basic braking pressure, the normal stress actuator 1 is responsible for precise pressure adjustment and disturbance suppression.

[0059] The motor 20 is connected to the lead screw shaft 24 through the gear 10 and the gear 19. The motor 20 can drive the lead screw shaft 24 to rotate. The rotation of the lead screw shaft 24 drives the lead screw nut 23 and the piston 15 to move linearly. The moving direction of the piston 15 is related to the rotation direction of the motor 20. When the piston 15 moves outwards, the output shaft 17 fixed on the piston 15 applies pressure to the pressing disc 4. A force sensor 18 is installed at the head of the output shaft 17 to measure the braking pressure. The lead screw nut 23 is fixed to the piston 15, and the piston 15 is fixed to the output shaft 17 by screws. The lead screw nut 23, the piston 15, and the output shaft 17 are all installed inside the outer cylinder 14. The outer cylinder 14 is connected to the upper end cover 16 and the lower end cover 13 by bolts. The guide ring 25 and the bearing set 22 serve as the axial supports for the output shaft 17 and the lead screw shaft 24. The bearing set 22 is embedded in the lower end cover 13, and the bearing pressure plate 21 is threadedly connected to the lower end cover 13 to prevent the bearing set 22 from coming out. The locking nut 11 is located at the end of the lead screw and is connected to the lead screw 4 by threads. When the locking nut 21 is tightened, the inner ring of the bearing will be squeezed tightly to prevent the lead screw shaft 24 from moving axially.

[0060] Threads are left at the stepped part of the output shaft 30. The rotor armature 34 is axially fixed to the output shaft 30 by a round nut 31. The output shaft 30 and the round nut 31 move together with the rotor armature 34. There are moving air gaps δ on both the left and right sides of the rotor armature 34 (when δ is larger, the output force decreases, and generally δ is less than 1 mm). The two parts of the stator 27-1 and the stator 27-2 have the same structure and are internally slotted. The coils 28-1 and 28-2 are respectively installed in the slots of the stator 27-1 and the stator 27-2. Grooves are left at the inner edges of the outer walls of the stator 27-1 and the stator 27-2. When the stator 27-1 and the stator 27-2 are combined into a whole, the permanent magnet ring 33 is embedded in the groove. Guide rings 29 and 32 are installed on both sides of the output shaft 30. The guide ring 29 and the guide ring 32 are respectively embedded in the central holes of the stator 27-1 and the stator 27-2 to provide axial support for the output shaft 30. The stator housings 26-1 and 26-2 have the same structure. During assembly, the stator 27-1 is embedded in the stator housing 26-1, and the stator 27-2 is embedded in the stator housing 26-2. Then the stator housing 26-1 and the stator housing 26-2 are fixedly connected by bolts to compress the internal components of the actuator. Openings are left on the outer walls of the stator housing 26-1, the stator housing 26-2, the stator 27-1, and the stator 27-2 for leading out the coil wires. The force on the rotor armature 34 is related to the current of the coils 28-1 and 28-2 and the axial air gap lengths on both sides of the rotor armature 34. By controlling the coil current, the force on the rotor armature can be adjusted, and thus the output force of the actuator can be controlled.

[0061] The magnetic motive force direction of the permanent magnet ring 33 is radial, pointing from the outer ring of the actuator to the inner ring. The magnetic flux generated by the permanent magnet enters the moving armature 34 radially, and enters the stators 27-1 and 27-2 respectively from both sides of the armature, and finally returns to the permanent magnet ring 33 through the stator, forming a complete magnetic circuit. Therefore, the magnetic flux directions caused by the permanent magnet ring 33 in the air gaps on both sides of the armature are opposite. The axial air gaps on both sides of the moving armature will change with the movement of the moving armature, but their sum always remains unchanged. When the axial air gaps on both sides of the moving armature 34 are equal (both are δ), the magnetic field intensities in the two air gaps are the same, and the resultant force on the moving armature 34 is 0 at this time; when the axial air gaps on both sides of the moving armature 34 are not equal (the sum is 2δ), the magnetic field intensities in the two air gaps are no longer the same, and the normal electromagnetic force on one side surface of the armature will be greater than that on the other side surface, and the resultant force is no longer 0. When the coils 28-1 and 28-2 are energized, the direction of the generated exciting magnetic flux is determined by the direction of the winding current, but the exciting magnetic flux directions in the air gaps on both sides of the armature are the same. Therefore, the exciting magnetic flux and the magnetic flux caused by the permanent magnet ring 33 are superimposed on each other in the air gap on one side of the armature and cancel each other out in the air gap on the other side, resulting in a change in the resultant force of the normal electromagnetic forces on both side surfaces of the armature. The resultant force of the normal electromagnetic forces on both side surfaces of the armature is the output force, and the output force can be adjusted by adjusting the coil current.

[0062] Embodiment 2

[0063] As Figure 12 and Figure 13 shown, a control method for an electric brake based on a normal stress actuator and an electromechanical actuator, the method selects a corresponding working mode according to the current brake pressure, the target brake pressure, the warning brake pressure and the basic brake pressure to perform precise braking or suppress disturbances, and the working mode includes three modes;

[0064] Mode 1: The electromechanical actuator 5 and the normal stress electromagnetic actuator 5 work together, the brake controller sends instructions to the current control electrical appliance and the servo controller at the same time, both the electromechanical actuator 5 and the normal stress electromagnetic actuator 1 are in the working state, and the brake disc is squeezed.

[0065] Mode 2: The electromechanical actuator 5 works alone, the brake controller sends instructions to the servo controller, the electromechanical actuator 5 is in the working state to squeeze the brake disc; the coil of the normal stress electromagnetic brake 1 is not energized.

[0066] Mode 3: The normal stress electromagnetic actuator 1 works alone, the brake controller sends instructions to the current controller, the electromechanical actuator 5 works in the locked mode, and the normal stress electromagnetic brake 1 is in the working state to squeeze the brake disc.

[0067] In this embodiment, the brake consists of a number of brake units, and each brake unit includes a brake controller, a current controller, a servo controller, a normal stress electromagnetic actuator, and an electromechanical actuator. The brake controller receives instructions from the flight control system, starts the braking action according to the instructions, and sets the target braking pressure. The current controller adjusts the output force of the normal stress electromagnetic actuator by controlling the coil current, and the servo controller adjusts the output shaft position of the electromechanical actuator by controlling the motor position. The brake controller calculates and determines the target current of the current controller and the target position of the servo controller according to the target braking pressure and the current braking pressure based on the control algorithm, and the current controller and the servo controller work according to the instructions of the brake controller.

[0068] Mode 1 (i.e., Figure 13 section I in

[0069] ): The electromechanical actuator and the normal stress electromagnetic actuator work together. The brake controller sends instructions to both the current control electrical appliance and the servo controller simultaneously (wherein, the current control electrical appliance receives the current control instruction, and the servo controller receives the position control instruction, and the instructions can be transmitted through analog signals or digital protocols such as Ethercat). The electromechanical actuator works in the position control mode, and the normal stress electromagnetic actuator works in the current control mode.

[0070] Mode 2 ( Figure 13 section II in

[0071] ): The electromechanical actuator works alone. The brake controller sends instructions to the servo controller, and the electromechanical actuator works in the position control mode; the coil of the normal stress electromagnetic brake is not energized, and the output shaft can move under the action of an external force.

[0072] Mode 3 ( Figure 13 section III in

[0073] ): The normal stress electromagnetic actuator works alone. The brake controller sends instructions to the current controller, the electromechanical actuator works in the locked mode, the motor is not energized but is locked in a specific position, and the output shaft cannot move under the action of an external force. The normal stress electromagnetic brake works in the current control mode.

[0074] The braking has the following process:

[0075] During the braking process, Mode 2 is first selected. The brake controller sends a position control instruction to the servo controller, and the servo controller controls the output shaft of the electromechanical actuator 5 to move and press against the brake disc;

[0076] Subsequently, it is adjusted to Mode 3. After the output shaft of the electromechanical actuator 5 moves into place, the electromechanical actuator 5 stops, the brake controller sends an instruction to the current controller, and the current controller adjusts the coil current according to the instruction to further press against the brake disc.

[0077] In this embodiment, during the braking process, the brake controller switches among three working modes according to the target braking pressure and the current braking pressure. After receiving the braking pressure command, the brake controller issues a position control command to the servo controller and adjusts the position control command according to the target braking pressure and the braking pressure feedback. The servo controller adjusts the motor speed according to the position control command and the position feedback, and drives the output shaft of the actuator to move. As the output shaft of the actuator continuously moves out, the brake discs are gradually pressed together, and the braking force continuously increases. At this time, the normal stress electromagnetic brake does not work, and its output shaft is squeezed by the brake discs to the limit position away from the brake discs. The brake works in Mode 2.

[0078] When the braking force reaches the basic braking pressure, due to the very high stiffness of the brake discs, the stroke required from the basic braking pressure to the target braking pressure is very small. At this time, it is adjusted to Working Mode 3, the electromechanical actuator stops working, and the output shaft of the electromechanical actuator remains stationary. The brake controller issues a command to the current controller and adjusts the current control command according to the target braking pressure. The current controller adjusts the coil current according to the current control command until the target braking pressure is reached.

[0079] The disturbance suppression has the following process:

[0080] S1. If the current braking pressure fluctuates within the range of the basic braking pressure and the warning braking pressure, then select Mode 3;

[0081] S11. In Mode 3, if the braking pressure is greater than the target braking pressure, then reduce the coil current of the normal application actuator (1), and the output shaft of the normal application actuator (1) releases the brake discs; if the braking pressure is less than the target braking pressure, then increase the coil current of the normal application actuator (1), and the output shaft of the normal application actuator (1) squeezes towards the brake discs.

[0082] The disturbance suppression also includes:

[0083] If the current braking pressure is lower than the basic braking pressure, then select Mode 1 until the current braking pressure returns to the range of the basic braking pressure and the warning braking pressure.

[0084] The disturbance suppression also includes:

[0085] If the current braking pressure is higher than the warning braking pressure, then select Mode 1 until the current braking pressure returns to the range of the basic braking pressure and the warning braking pressure.

[0086] In this embodiment, the brake discs will generate relatively severe vibrations due to friction, forming a disturbance to the braking system and causing fluctuations in the braking pressure. The response to this fluctuation is divided into three cases:

[0087] 1) The fluctuation amplitude is within the range of the basic braking pressure and the warning braking pressure: It still operates in Mode 3. Specifically: If the current braking pressure is greater than the target braking pressure, the actuator coil current is decreased, and the output shaft of the actuator releases the brake disc; if the braking pressure is less than the target braking pressure, the actuator coil current is increased, and the output shaft of the actuator presses against the brake disc.

[0088] 2) The fluctuation causes the current braking pressure to be lower than the basic braking pressure: It is adjusted to Mode 1, the output shaft of the electromechanical actuator moves towards the brake disc, and at the same time, the actuator coil current is increased; when the braking pressure returns to the range of the basic braking pressure and the warning braking pressure, it is adjusted to Mode 3, the actuator coil current is increased, and the output shaft of the actuator presses against the brake disc.

[0089] 3) The fluctuation causes the current braking pressure to be higher than the warning braking pressure: It is adjusted to Mode 1, the output shaft of the electromechanical actuator releases the brake disc, and at the same time, the actuator coil current is decreased; when the braking pressure returns to the range of the basic braking pressure and the warning braking pressure, it is adjusted to Mode 3, and the actuator coil current continues to be decreased, and the output shaft of the actuator releases the brake disc.

[0090] The target braking pressure needs to be set according to specific requirements. The target braking pressure is generated by the aircraft's total control system, and it is different for different aircraft models. The basic braking pressure is set to 0.9 times the target braking pressure, and the warning braking pressure is set to 1.1 times the target braking pressure.

[0091] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An electric brake based on a normal stress actuator and an electromechanical actuator, the electric brake being used for a wheel of an aircraft, characterized in that: The electric brake comprises a normal stress actuator (1), a brake disc, an electromechanical actuator (5), a brake controller, a servo controller and a current controller. The normal stress actuator (1) and the electromechanical actuator (5) are respectively installed on both sides of the brake disc and are symmetrical. The brake controller is respectively connected to the servo controller and the current controller. The servo controller is connected to the electromechanical actuator (5). The current controller is connected to the normal stress actuator (1). The electromechanical actuator (5) detects the current brake pressure. The brake controller selects a corresponding working mode according to the current brake pressure, the target brake pressure, the warning brake pressure and the basic brake pressure, thereby controlling the pressure of the normal stress actuator (1) and the electromechanical actuator (5) on the brake disc, thereby achieving precise braking of the wheel and suppressing disturbances.

2. The electric brake based on the normal stress actuator and the electromechanical actuator according to claim 1, characterized in that: The electric brake further comprises a clamping disc (4) and a pressure disc (7), the electromechanical actuator (5) being mounted on the brake disc via the clamping disc (4), and the normal stress actuator (1) being mounted on the brake disc via the pressure disc (7).

3. The electric brake based on the normal stress actuator and the electromechanical actuator according to claim 2, characterized in that: The electromechanical actuator (5) and the normal stress actuator (1) both comprise an output shaft, the output shaft of the electromechanical actuator (5) is connected to a pressure plate (4), and the output shaft of the normal stress actuator (1) is connected to a pressure plate (7).

4. The electric brake based on the normal stress actuator and the electromechanical actuator according to claim 3, characterized in that: The electromechanical actuator (5) further comprises a force sensor (18), wherein the force sensor (18) is mounted on the output shaft of the electromechanical actuator (5).

5. The electric brake based on normal stress actuator and electromechanical actuator according to claim 2, characterized in that: The electric brake further comprises a brake housing (8), the brake disc comprises a static disc (2) and a dynamic disc (3), the dynamic disc (3) is connected to the wheel, and the static disc (2) and the brake housing (8) are fixed.

6. A control method for an electric brake based on a normal stress actuator and an electromechanical actuator as claimed in any one of claims 1 to 5, characterized in that: The method selects a corresponding working mode according to the current brake pressure, the target brake pressure, the warning brake pressure and the basic brake pressure to perform precise braking or suppress disturbances. The working mode includes three modes; Mode 1: the electromechanical actuator (5) and the normal stress electromagnetic actuator (5) work together, the brake controller sends instructions to the current control device and the servo controller at the same time, and the electromechanical actuator (5) and the normal stress electromagnetic actuator (1) are both in working state, squeezing the brake disc; Mode 2: the electromechanical actuator (5) works alone, the brake controller sends instructions to the servo controller, the electromechanical actuator (5) is in a working state to squeeze the brake disc; the coil of the normal stress electromagnetic brake (1) is not energized; Mode three: the normal stress electromagnetic actuator (1) works alone, the brake controller sends instructions to the current controller, the electromechanical actuator (5) works in the locking mode, and the normal stress electromagnetic brake (1) is in a working state to squeeze the brake disc.

7. The control method according to claim 6, characterized in that: The braking process is as follows: During the braking process, mode 2 is first selected, the brake controller sends a position control instruction to the servo controller, and the servo controller controls the output shaft of the electromechanical actuator (5) to move and press the brake disc; Then it is adjusted to mode three. After the output shaft of the electromechanical actuator (5) moves into position, the electromechanical actuator (5) stops, and the brake controller sends a command to the current controller. The current controller adjusts the coil current according to the command, thereby pressing the brake disc.

8. The control method according to claim 6, characterized in that: The disturbance suppression has the following process: S1. If the current brake pressure fluctuates within the range of the basic brake pressure and the warning brake pressure, select mode 3; S11. In mode three, if the braking pressure is greater than the target braking pressure, the coil current of the normal application actuator (1) is reduced, and the output shaft of the normal application actuator (1) releases the brake disc; if the braking pressure is less than the target braking pressure, the coil current of the normal application actuator (1) is increased, and the output shaft of the normal application actuator (1) is pressed toward the brake disc.

9. The control method according to claim 6, characterized in that: The disturbance suppression also includes: If the current brake pressure is lower than the basic brake pressure, mode 1 is selected until the current brake pressure returns to the range of the basic brake pressure and the warning brake pressure.

10. The control method according to claim 6, characterized in that: The disturbance suppression also includes: If the current brake pressure is higher than the warning brake pressure, mode 1 is selected until the current brake pressure returns to the range of the basic brake pressure and the warning brake pressure.

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