Electro-hydrostatic brake system of unmanned aerial vehicle

Abstract

The invention relates to the technical field of braking systems, in particular to an electro-hydrostatic braking system of an unmanned aerial vehicle. The electro-hydrostatic brake system of the unmanned aerial vehicle is only provided with two sets of hydraulic pipelines; wherein one set comprises a first hydraulic power unit, a first pipeline, a first normally open solenoid valve, a second pipeline and a first hydraulic braking module; the other set comprises a second hydraulic power unit, a third pipeline, a second normally open solenoid valve, a fourth pipeline and a second hydraulic brake module; when the first hydraulic power unit breaks down, the flight controller controls the first normally-open electromagnetic valve to be closed and controls the normally-closed electromagnetic valve to be opened, so that oil is supplied to the first hydraulic braking module through the second hydraulic power unit. When the second hydraulic power unit breaks down, the flight controller controls the second normally-open electromagnetic valve to be closed and controls the normally-closed electromagnetic valve to be opened, so that oil is supplied to the second hydraulic braking module through the first hydraulic power unit. The air load weight of the unmanned aerial vehicle is reduced, so that the effective load of the unmanned aerial vehicle is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of brake systems, and in particular to an electrostatic hydraulic brake system for unmanned aerial vehicles. Background Art

[0002] Unmanned aerial vehicle, referred to as "UAV", is an unmanned aircraft controlled by radio remote control equipment and self-contained program control devices, or an unmanned aircraft operated completely or intermittently autonomously by an onboard computer; UAVs need to use a braking system for braking when landing. Currently, the commonly used UAV braking systems mainly include normal braking systems and emergency braking systems. The normal braking system is used to realize the UAV's static braking, normal braking, correction braking and release braking functions; the emergency braking system is used for emergency braking.

[0003] At present, the normal braking system of the UAV is realized by an electric proportional valve, and the emergency braking system is realized by a pneumatic brake structure. The hydraulic pipelines of the entire braking system are divided into two sets, each set of hydraulic pipelines includes left wheel pipelines and right wheel pipelines, so four sets of hydraulic pipelines are actually configured; this layout scheme leads to a large number of accessories in the entire braking system, which increases the unloaded weight of the UAV and results in a low payload of the UAV. Summary of the invention

[0004] The main purpose of the present invention is to provide an electrostatic hydraulic brake system for a UAV, aiming to solve the problem that the existing UAV brake system has a large number of accessories, which increases the unloaded weight of the UAV and results in a low payload of the UAV.

[0005] To achieve the above purpose, the technical solution proposed by the present invention is:

[0006] An unmanned aerial vehicle electrostatic hydraulic brake system comprises a flight controller, a first hydraulic power unit, a second hydraulic power unit, a first normally open solenoid valve, a second normally open solenoid valve, a normally closed solenoid valve, a first hydraulic brake module and a second hydraulic brake module arranged on the unmanned aerial vehicle; the first hydraulic brake module is arranged on the left wheel of the unmanned aerial vehicle, and the second hydraulic brake module is arranged on the right wheel of the unmanned aerial vehicle; the first hydraulic power unit, the second hydraulic power unit, the first normally open solenoid valve, the second normally open solenoid valve and the normally closed solenoid valve are all communicatively connected to the flight controller; the oil outlet of the first hydraulic power unit is connected to the inlet end of the first normally open solenoid valve through a first pipeline; the outlet end of the first normally open solenoid valve is connected to the first hydraulic brake through a second pipeline The oil inlet of the module; the oil outlet of the second hydraulic power unit is connected to the inlet end of the second normally open solenoid valve through a third pipe; the outlet end of the second normally open solenoid valve is connected to the oil inlet of the second hydraulic brake module through a fourth pipe; the normally closed solenoid valve is connected between the second pipe and the fourth pipe; the flight controller is used for: when the first hydraulic power unit fails, controlling the first normally open solenoid valve to close, and controlling the normally closed solenoid valve to open, so as to supply oil to the first hydraulic brake module through the second hydraulic power unit; when the second hydraulic power unit fails, controlling the second normally open solenoid valve to close, and controlling the normally closed solenoid valve to open, so as to supply oil to the second hydraulic brake module through the first hydraulic power unit.

[0007] Preferably, the first hydraulic power unit and the second hydraulic power unit are both brushless motor hydraulic power units; the flight controller is used to control the speed of the brushless motor of the brushless motor hydraulic power unit to adjust the pressure of the oil output by the first hydraulic power unit and the second hydraulic power unit; the second pipeline is provided with a first three-way pipe; the fourth pipeline is provided with a second three-way pipe; the normally closed solenoid valve is arranged between the first three-way pipe and the second three-way pipe; the first hydraulic power unit is provided with a first control unit; the second hydraulic power unit is provided with a second control unit; the flight controller is also used to: obtain in real time the pressure of the oil output by the first hydraulic power unit collected by the first control unit to determine whether the first hydraulic power unit has a fault; obtain in real time the pressure of the oil output by the second hydraulic power unit collected by the second control unit to determine whether the second hydraulic power unit has a fault.

[0008] Preferably, the system also includes a first grounding sensor for detecting whether the left wheel is grounded; the flight controller is also used to: obtain the flight status of the UAV to determine whether the UAV is in a landing state; when the UAV is in a landing state, determine whether the landing gear of the UAV is in a state of extending from the fuselage; when the landing gear of the UAV is in a state of extending from the fuselage, determine that the UAV enters a grounding protection state; when the UAV is in a grounding protection state, control the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel, and at the same time receive a signal from the first grounding sensor to determine whether the left wheel is on the ground; if the left wheel is on the ground and the duration of the grounding is greater than a first preset time, control the first hydraulic power unit to start to output oil to the first hydraulic brake module to brake the left wheel.

[0009] Preferably, the system also includes a first speed sensor for detecting the rotational speed of the left wheel; the flight controller is also used to: receive the rotational speed from the first speed sensor to calculate the real-time speed of the left wheel relative to the ground; when the UAV is in a ground protection state, determine whether the following conditions are met: the real-time speed of the left wheel relative to the ground is continuously greater than the first preset speed within a second preset time period; if so, control the first hydraulic power unit to start to output oil to the first hydraulic brake module to brake the left wheel.

[0010] Preferably, the system also includes a second grounding sensor for detecting whether the right wheel is grounded; the flight controller is also used to: when the UAV is in a ground protection state, control the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel, and at the same time receive a signal from the second grounding sensor to determine whether the left wheel is on the ground; if the right wheel is on the ground and the duration of the landing is greater than a first preset time, control the second hydraulic power unit to start to output oil to the second hydraulic brake module to brake the right wheel.

[0011] Preferably, the system also includes a second speed sensor for detecting the rotational speed of the right wheel; the flight controller is also used to: receive the rotational speed from the second speed sensor to calculate the real-time speed of the right wheel relative to the ground; when the UAV is in a ground protection state, determine whether the following conditions are met: the real-time speed of the right wheel relative to the ground is continuously greater than the first preset speed within a second preset time period; if so, control the second hydraulic power unit to start to output oil to the second hydraulic brake module to brake the right wheel.

[0012] Preferably, the flight controller is also used to: determine whether the following conditions are met: the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time are both greater than a first preset value, and the difference between the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time is greater than a second preset value; if so, compare the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground; when the real-time speed of the left wheel relative to the ground is greater than the real-time speed of the right wheel relative to the ground, control the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel; when the real-time speed of the left wheel relative to the ground is less than the real-time speed of the right wheel relative to the ground, control the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel.

[0013] Preferably, the flight controller is also used for: generating a landing gear brake command when the landing gear of the UAV is retracted into the fuselage and the left and right wheels are both in an ungrounded state; controlling the first hydraulic power unit to start based on the landing gear brake command to output oil to the first hydraulic brake module to brake the left wheel; controlling the second hydraulic power unit to start based on the landing gear brake command to output oil to the second hydraulic brake module to brake the right wheel; and when the duration of generating the landing gear brake command exceeds a third preset duration, controlling the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel, and at the same time controlling the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel.

[0014] Preferably, the flight controller is also used to: generate a takeoff line parking brake command; control the first hydraulic power unit to start based on the takeoff line parking brake command to output oil to the first hydraulic brake module to brake the left wheel; control the second hydraulic power unit to start based on the takeoff line parking brake command to output oil to the second hydraulic brake module to brake the right wheel.

[0015] Preferably, the system also includes a first oil cup and a second oil cup; the first oil cup is connected to the first hydraulic power unit; the second oil cup is connected to the second hydraulic power unit; the oil outlet of the first hydraulic brake module is connected to the oil inlet of the first hydraulic power unit; the oil outlet of the second hydraulic brake module is connected to the oil inlet of the second hydraulic power unit.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] The UAV electrostatic brake system proposed in the present invention is only provided with two sets of hydraulic pipelines; one set is the first hydraulic power unit-first pipeline-first normally open solenoid valve-second pipeline-first hydraulic brake module; the other set is the second hydraulic power unit-third pipeline-second normally open solenoid valve-fourth pipeline-second hydraulic brake module; a normally closed solenoid valve is arranged between the second pipeline and the fourth pipeline; this scheme can ensure that both the left and right wheels can decelerate and stop normally even if a fault occurs under the premise of only having two sets of hydraulic pipelines; the specific scheme is: when the first hydraulic power unit fails, the flight controller controls the first normally open solenoid valve to close, and controls the normally closed solenoid valve Open to supply oil to the first hydraulic brake module through the second hydraulic power unit, so that the left wheel can be decelerated even when the first hydraulic power unit fails; when the second hydraulic power unit fails, the flight controller controls the second normally open solenoid valve to close, and controls the normally closed solenoid valve to open, so that oil is supplied to the second hydraulic brake module through the first hydraulic power unit, so that the right wheel can be decelerated even when the second hydraulic power unit fails; this solution can ensure normal braking and fault backup braking under the premise of only setting 2 sets of hydraulic pipelines; compared with the existing UAV braking system, the unloaded weight of the UAV is greatly reduced, thereby increasing the UAV's payload. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0019] Figure 1 This is a structural framework diagram of an embodiment of the UAV electrostatic hydraulic brake system proposed by the present invention.

[0020] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] The invention provides an electrostatic hydraulic brake system for a drone.

[0027] As attached Figure 1As shown, in one embodiment of an electrostatic hydraulic brake system for a drone proposed by the present invention, based on the first embodiment, the electrostatic hydraulic brake system for a drone includes a flight controller, a first hydraulic power unit, a second hydraulic power unit, a first normally open solenoid valve, a second normally open solenoid valve, a normally closed solenoid valve, a first hydraulic brake module, and a second hydraulic brake module arranged on the drone; the first hydraulic brake module is arranged on the left wheel of the drone, and the second hydraulic brake module is arranged on the right wheel of the drone; the first hydraulic power unit, the second hydraulic power unit, the first normally open solenoid valve, the second normally open solenoid valve and the normally closed solenoid valve are all communicatively connected to the flight controller; the oil outlet of the first hydraulic power unit is connected to the inlet end of the first normally open solenoid valve through a first pipeline; the first The outlet end of the normally open solenoid valve is connected to the oil inlet of the first hydraulic brake module through the second pipeline; the oil outlet of the second hydraulic power unit is connected to the inlet end of the second normally open solenoid valve through the third pipeline; the outlet end of the second normally open solenoid valve is connected to the oil inlet of the second hydraulic brake module through the fourth pipeline; a normally closed solenoid valve is connected between the second pipeline and the fourth pipeline; the flight controller is used to: when the first hydraulic power unit fails, control the first normally open solenoid valve to close, and control the normally closed solenoid valve to open, so as to supply oil to the first hydraulic brake module through the second hydraulic power unit; when the second hydraulic power unit fails, control the second normally open solenoid valve to close, and control the normally closed solenoid valve to open, so as to supply oil to the second hydraulic brake module through the first hydraulic power unit.

[0028] The UAV electrostatic brake system proposed in the present invention is only provided with two sets of hydraulic pipelines; one set is the first hydraulic power unit-first pipeline-first normally open solenoid valve-second pipeline-first hydraulic brake module; the other set is the second hydraulic power unit-third pipeline-second normally open solenoid valve-fourth pipeline-second hydraulic brake module; a normally closed solenoid valve is arranged between the second pipeline and the fourth pipeline; this scheme can ensure that both the left and right wheels can decelerate and stop normally even if a fault occurs under the premise of only having two sets of hydraulic pipelines; the specific scheme is: when the first hydraulic power unit fails, the flight controller controls the first normally open solenoid valve to close, and controls the normally closed solenoid valve Open to supply oil to the first hydraulic brake module through the second hydraulic power unit, so that the left wheel can be decelerated even when the first hydraulic power unit fails; when the second hydraulic power unit fails, the flight controller controls the second normally open solenoid valve to close, and controls the normally closed solenoid valve to open, so that oil is supplied to the second hydraulic brake module through the first hydraulic power unit, so that the right wheel can be decelerated even when the second hydraulic power unit fails; this solution can ensure normal braking and fault backup braking under the premise of only setting 2 sets of hydraulic pipelines; compared with the existing UAV braking system, the unloaded weight of the UAV is greatly reduced, thereby increasing the UAV's payload.

[0029] In addition, the first hydraulic power unit and the second hydraulic power unit are both brushless motor hydraulic power units; the flight controller is used to control the speed of the brushless motor of the brushless motor hydraulic power unit to adjust the pressure of the oil output by the first hydraulic power unit and the second hydraulic power unit; the second pipeline is provided with a first three-way pipe; the fourth pipeline is provided with a second three-way pipe; the normally closed solenoid valve is provided between the first three-way pipe and the second three-way pipe; the first hydraulic power unit is provided with a first control unit (pressure sensor); the second hydraulic power unit is provided with a second control unit (pressure sensor); the flight controller is also used to: obtain in real time the pressure of the oil output by the first hydraulic power unit collected by the first control unit to determine whether the first hydraulic power unit has a fault; obtain in real time the pressure of the oil output by the second hydraulic power unit collected by the second control unit to determine whether the second hydraulic power unit has a fault.

[0030] At the same time, the system also includes a first grounding sensor for detecting whether the left wheel is grounded; the flight controller is also used to: obtain the flight status of the UAV to determine whether the UAV is in a landing state; when the UAV is in a landing state, determine whether the landing gear of the UAV is in a state of extending from the fuselage; when the landing gear of the UAV is in a state of extending from the fuselage, determine that the UAV enters a grounding protection state; when the UAV is in a grounding protection state, control the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel, and at the same time receive a signal from the first grounding sensor to determine whether the left wheel is on the ground; if the left wheel is on the ground and the duration of the grounding is greater than a first preset time (for example, 2 seconds), control the first hydraulic power unit to start to output oil to the first hydraulic brake module to brake the left wheel.

[0031] Through the above technical solution, the drone can be stopped normally during landing; the left wheel of the drone is not braked at the moment it touches the ground (i.e., it enters the ground protection state) to prevent the left wheel from being braked due to excessive acceleration at the moment of touching the ground, which may cause a tire blowout on the left wheel; therefore, the left wheel is braked more than 2 seconds after the left wheel touches the ground.

[0032] In addition, the system also includes a first speed sensor for detecting the rotation speed of the left wheel; the flight controller is also used to: receive the rotation speed from the first speed sensor to calculate the real-time speed of the left wheel relative to the ground (the real-time speed of the left wheel relative to the ground can be calculated based on the diameter of the left wheel); when the UAV is in a ground protection state, determine whether the following conditions are met: the real-time speed of the left wheel relative to the ground is continuously greater than the first preset speed (for example, 35 km / h) within a second preset time length (for example, 250 milliseconds); if so, control the first hydraulic power unit to start to output oil to the first hydraulic brake module to brake the left wheel.

[0033] Specifically, when the UAV is in a ground protection state, if the real-time speed of the left wheel relative to the ground continues to be greater than the first preset speed within a second preset time period, it proves that the speed of the left wheel has reached a level that requires braking, so the first hydraulic power unit is controlled to start to brake the left wheel.

[0034] In addition, the system also includes a second grounding sensor for detecting whether the right wheel is grounded; the flight controller is also used to: when the UAV is in a ground protection state, control the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel, and at the same time receive a signal from the second grounding sensor to determine whether the left wheel is on the ground; if the right wheel is on the ground and the duration of the landing is greater than the first preset time, control the second hydraulic power unit to start to output oil to the second hydraulic brake module to brake the right wheel.

[0035] Through the above technical solution, the drone can be stopped normally during landing; the right wheel of the drone is not braked at the moment it touches the ground (i.e., it enters the ground protection state) to prevent the right wheel from being braked due to excessive acceleration at the moment of touching the ground, which may cause a tire blowout on the right wheel; therefore, the right wheel is braked more than 2 seconds after the right wheel touches the ground.

[0036] At the same time, the system also includes a second speed sensor for detecting the rotation speed of the right wheel; the flight controller is also used to: receive the rotation speed from the second speed sensor to calculate the real-time speed of the right wheel relative to the ground; when the UAV is in a ground protection state, determine whether the following conditions are met: the real-time speed of the right wheel relative to the ground continues to be greater than the first preset speed within a second preset time period; if so, control the second hydraulic power unit to start to output oil to the second hydraulic brake module to brake the right wheel.

[0037] Specifically, when the UAV is in the ground protection state, if the real-time speed of the right wheel relative to the ground continues to be greater than the first preset speed within a second preset time period, it proves that the speed of the right wheel has reached a level that requires braking, so the second hydraulic power unit is controlled to start to brake the right wheel.

[0038] In addition, the flight controller is also used to: determine whether the following conditions are met: the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time are both greater than a first preset value (for example, 55 km / h), and the difference between the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time is greater than a second preset value (the second preset value is 30% of the larger of the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time); if so, compare the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground; when the real-time speed of the left wheel relative to the ground is greater than the real-time speed of the right wheel relative to the ground, control the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel; when the real-time speed of the left wheel relative to the ground is less than the real-time speed of the right wheel relative to the ground, control the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel.

[0039] Specifically, when the speeds of the two wheels are both greater than the first preset value, it means that the speeds of the two wheels are both relatively large, and the difference between the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time is greater than the second preset value, which means that the speed difference between the two wheels is relatively large. In order to prevent the wheels from slipping, it is necessary to release the brakes of the slower wheel to balance the speeds between the left and right wheels; therefore, when the real-time speed of the left wheel relative to the ground is greater than the real-time speed of the right wheel relative to the ground, the second hydraulic power unit is controlled to stop to release the right wheel; and when the real-time speed of the left wheel relative to the ground is less than the real-time speed of the right wheel relative to the ground, the first hydraulic power unit is controlled to stop to release the left wheel.

[0040] At the same time, the flight controller is also used to: when the landing gear of the UAV is retracted into the fuselage, and the left and right wheels are both in an ungrounded state, generate a landing gear brake command; based on the landing gear brake command, control the first hydraulic power unit to start, so as to output oil to the first hydraulic brake module to brake the left wheel; based on the landing gear brake command, control the second hydraulic power unit to start, so as to output oil to the second hydraulic brake module to brake the right wheel; that is, after the landing gear is retracted into the fuselage, the left and right wheels that continue to rotate due to inertia can be braked in time; when the duration of generating the landing gear brake command exceeds the third preset duration (15 seconds), control the first hydraulic power unit to stop, so that the first hydraulic brake module releases the left wheel, and control the second hydraulic power unit to stop, so that the second hydraulic brake module releases the right wheel. When the braking duration exceeds 15 seconds, the left and right wheels have been braked, so the left and right wheels are directly released.

[0041] In addition, the flight controller is also used to: generate a takeoff line parking brake command; control the start-up of the first hydraulic power unit based on the takeoff line parking brake command to output oil to the first hydraulic brake module to brake the left wheel; control the start-up of the second hydraulic power unit based on the takeoff line parking brake command to output oil to the second hydraulic brake module to brake the right wheel.

[0042] Specifically, when the take-off line parking brake command is generated, the UAV's engine starts, but the first hydraulic brake module starts to brake the left wheel, and the second hydraulic brake module starts to brake the right wheel, so that the UAV stops at the take-off line and prepares for take-off. It is worth noting that the continuous working time of the take-off line parking brake is no more than 60 minutes, and the standard pressure of the first hydraulic brake module and the second hydraulic brake module during the parking brake is 8MPa.

[0043] The flight controller is also used to: generate differential braking instructions; control the first hydraulic power unit and the second hydraulic power unit to start simultaneously based on the differential braking instructions, and the first hydraulic power unit and the second hydraulic power unit output oil pressures at different levels; adjust the braking force of the left and right wheels by outputting oil of different pressures to the left and right wheels respectively, and then control the deceleration rate and taxiing speed of the left and right wheels of the drone to achieve the differential braking function.

[0044] At the same time, the system also includes a control terminal arranged on the ground; the control terminal is connected to the flight controller in communication (wireless communication connection); the flight controller is also used to: generate an autonomous braking command when a communication failure occurs between the control terminal and the flight controller; when the UAV enters the landing state, the landing gear is controlled to extend from the fuselage based on the autonomous braking command, and the real-time speed of the left wheel relative to the ground is obtained based on the first speed sensor, and the real-time speed of the right wheel relative to the ground is obtained based on the second speed sensor; when the left wheel touches the ground for a time period greater than a first preset time period (for example, 2 seconds) or the real-time speed of the left wheel relative to the ground is greater than a second preset speed (for example, 40 km / h), , control the first hydraulic power unit to start, so as to output oil to the first hydraulic brake module to brake the left wheel, and during the braking process, the oil pressure output by the first hydraulic power unit decreases as the real-time speed of the left wheel relative to the ground decreases; when the right wheel touches the ground for a time longer than a first preset time (for example, 2 seconds) or the real-time speed of the right wheel relative to the ground is greater than a second preset speed (for example, 40 km / h), control the second hydraulic power unit to start, so as to output oil to the second hydraulic brake module to brake the right wheel, and during the braking process, the oil pressure output by the second hydraulic power unit decreases as the real-time speed of the right wheel relative to the ground decreases.

[0045] In addition, the system also includes a first oil cup and a second oil cup; the first oil cup is connected to the first hydraulic power unit; the second oil cup is connected to the second hydraulic power unit; the oil outlet of the first hydraulic brake module is connected to the oil inlet of the first hydraulic power unit; the oil outlet of the second hydraulic brake module is connected to the oil inlet of the second hydraulic power unit.

[0046] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An electrostatic hydraulic brake system for a drone, characterized in that: It includes a flight controller, a first hydraulic power unit, a second hydraulic power unit, a first normally open solenoid valve, a second normally open solenoid valve, a normally closed solenoid valve, a first hydraulic brake module and a second hydraulic brake module arranged on a drone; the first hydraulic brake module is arranged on the left wheel of the drone, and the second hydraulic brake module is arranged on the right wheel of the drone; the first hydraulic power unit, the second hydraulic power unit, the first normally open solenoid valve, the second normally open solenoid valve and the normally closed solenoid valve are all communicatively connected to the flight controller; the oil outlet of the first hydraulic power unit is connected to the inlet end of the first normally open solenoid valve through a first pipeline; the outlet end of the first normally open solenoid valve is connected to the oil inlet of the first hydraulic brake module through a second pipeline; The oil outlet of the second hydraulic power unit is connected to the inlet end of the second normally open solenoid valve through a third pipeline; the outlet end of the second normally open solenoid valve is connected to the oil inlet of the second hydraulic brake module through a fourth pipeline; the normally closed solenoid valve is connected between the second pipeline and the fourth pipeline; the flight controller is used to: when the first hydraulic power unit fails, control the first normally open solenoid valve to close, and control the normally closed solenoid valve to open, so as to supply oil to the first hydraulic brake module through the second hydraulic power unit; when the second hydraulic power unit fails, control the second normally open solenoid valve to close, and control the normally closed solenoid valve to open, so as to supply oil to the second hydraulic brake module through the first hydraulic power unit.

2. The UAV electrostatic hydraulic brake system according to claim 1, characterized in that: The first hydraulic power unit and the second hydraulic power unit are both brushless motor hydraulic power units; the flight controller is used to control the speed of the brushless motor of the brushless motor hydraulic power unit to adjust the pressure of the oil output by the first hydraulic power unit and the second hydraulic power unit; the second pipeline is provided with a first three-way pipe; the fourth pipeline is provided with a second three-way pipe; the normally closed solenoid valve is arranged between the first three-way pipe and the second three-way pipe; the first hydraulic power unit is provided with a first control unit; the second hydraulic power unit is provided with a second control unit; the flight controller is also used to: obtain the pressure of the oil output by the first hydraulic power unit collected by the first control unit in real time to determine whether the first hydraulic power unit has a fault; obtain the pressure of the oil output by the second hydraulic power unit collected by the second control unit in real time to determine whether the second hydraulic power unit has a fault.

3. The UAV electrostatic hydraulic brake system according to claim 1, characterized in that: The system also includes a first grounding sensor for detecting whether the left wheel is grounded; the flight controller is also used to: obtain the flight status of the UAV to determine whether the UAV is in a landing state; when the UAV is in a landing state, determine whether the landing gear of the UAV is in a state of extending from the fuselage; when the landing gear of the UAV is in a state of extending from the fuselage, determine that the UAV enters a grounding protection state; when the UAV is in a grounding protection state, control the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel, and at the same time receive a signal from the first grounding sensor to determine whether the left wheel is on the ground; if the left wheel is on the ground and the duration of the grounding is greater than a first preset time, control the first hydraulic power unit to start to output oil to the first hydraulic brake module to brake the left wheel.

4. The UAV electrostatic hydraulic brake system according to claim 3, characterized in that: The system also includes a first speed sensor for detecting the rotation speed of the left wheel; the flight controller is also used to: receive the rotation speed from the first speed sensor to calculate the real-time speed of the left wheel relative to the ground; when the UAV is in a ground protection state, determine whether the following conditions are met: the real-time speed of the left wheel relative to the ground continues to be greater than the first preset speed within a second preset time period; if so, control the first hydraulic power unit to start to output oil to the first hydraulic brake module to brake the left wheel.

5. The UAV electrostatic hydraulic brake system according to claim 4, characterized in that: The system also includes a second grounding sensor for detecting whether the right wheel is grounded; the flight controller is also used to: when the UAV is in a ground protection state, control the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel, and at the same time receive a signal from the second grounding sensor to determine whether the left wheel is on the ground; if the right wheel is on the ground and the duration of the grounding is greater than a first preset time, control the second hydraulic power unit to start to output oil to the second hydraulic brake module to brake the right wheel.

6. The UAV electrostatic brake system according to claim 5, characterized in that: The system also includes a second speed sensor for detecting the rotation speed of the right wheel; the flight controller is also used to: receive the rotation speed from the second speed sensor to calculate the real-time speed of the right wheel relative to the ground; when the UAV is in a ground protection state, determine whether the following conditions are met: the real-time speed of the right wheel relative to the ground continues to be greater than the first preset speed within a second preset time period; if so, control the second hydraulic power unit to start to output oil to the second hydraulic brake module to brake the right wheel.

7. The UAV electrostatic brake system according to claim 6, characterized in that: The flight controller is also used to: determine whether the following conditions are met: the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time are both greater than a first preset value, and the difference between the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground at the same time is greater than a second preset value; if so, compare the real-time speed of the left wheel relative to the ground and the real-time speed of the right wheel relative to the ground; when the real-time speed of the left wheel relative to the ground is greater than the real-time speed of the right wheel relative to the ground, control the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel; when the real-time speed of the left wheel relative to the ground is less than the real-time speed of the right wheel relative to the ground, control the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel.

8. The UAV electrostatic hydraulic brake system according to claim 5, characterized in that: The flight controller is also used to: generate a landing gear brake command when the landing gear of the UAV is retracted into the fuselage and the left and right wheels are both in an ungrounded state; control the first hydraulic power unit to start based on the landing gear brake command to output oil to the first hydraulic brake module to brake the left wheel; control the second hydraulic power unit to start based on the landing gear brake command to output oil to the second hydraulic brake module to brake the right wheel; when the duration of generating the landing gear brake command exceeds a third preset duration, control the first hydraulic power unit to stop so that the first hydraulic brake module releases the left wheel, and at the same time control the second hydraulic power unit to stop so that the second hydraulic brake module releases the right wheel.

9. The UAV electrostatic hydraulic brake system according to claim 5, characterized in that: The flight controller is also used to: generate a takeoff line parking brake command; control the first hydraulic power unit to start based on the takeoff line parking brake command to output oil to the first hydraulic brake module to brake the left wheel; control the second hydraulic power unit to start based on the takeoff line parking brake command to output oil to the second hydraulic brake module to brake the right wheel.

10. The UAV electrostatic hydraulic brake system according to claim 1, characterized in that: The system further comprises a first oil cup and a second oil cup; the first oil cup is connected to the first hydraulic power unit; the second oil cup is connected to the second hydraulic power unit; the oil outlet of the first hydraulic brake module is connected to the oil inlet of the first hydraulic power unit; The oil outlet of the second hydraulic brake module is communicated with the oil inlet of the second hydraulic power unit.

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