A power management system for an unmanned aerial vehicle rudder system

Abstract

The present invention discloses a power management system for a drone rudder system, belonging to the field of the design of electric rudder systems for aircraft. It includes a hardware part and a software part. The hardware part includes a battery voltage monitoring and judging circuit, a main control chip, and a host computer connected in sequence. The software part includes a fault logic determination module, a communication module, and a fault removal module. The fault software logic determination module is used to adopt corresponding control strategies when the battery voltage exceeds the threshold range. The communication module is used for the main control chip to report the fault status to the host computer. The fault removal module is used for the main control chip to determine the working state of the rudder system according to the voltage state. The present invention can avoid the problem of small-angle misoperation of the rudder system caused by low battery voltage on the aircraft. At the same time, it can enable the flight control computer to quickly locate the fault and cut off the rudder system to protect the rudder system from the influence of low battery voltage.

Description

Technical Field

[0001] The present invention relates to the field of the design of electric rudder systems for aircraft, and particularly to a power management system for the rudder system of an unmanned aerial vehicle (UAV). Background Art

[0002] In recent years, with the rapid development of aerospace technology, the rudder systems supporting UAVs have developed rapidly towards the direction of intelligence. As a key actuator of a UAV, the performance of the electric rudder system directly affects the overall performance of the UAV.

[0003] Based on the research of a certain UAV, it is found that when the rudder system is jointly debugged with the host system, there will occasionally be a phenomenon that the rudder system does not act or there are tiny movements at the moment of power-off. After investigation, this problem is related to the on-board power supply. The on-board power supply for the rudder system is composed of lithium batteries, and the charge of the battery is closely related to the reliability of the entire power supply system. The more remaining power of the battery, the higher the reliability of the system. For example, the host power supply voltage range is 28±6V (there will be differences for different aircraft), and within this range, the rudder system can ensure normal output. Because before leaving the factory, the rudder system will conduct a pull-off test according to the voltage range and then be delivered. However, after the battery is used for a period of time, it will decay, resulting in a situation where the battery operates with low power, and the output voltage drops below 22V or even lower. Since there is a margin in the design of the rudder system (the lowest is 18V), when the battery output is at this critical voltage, the rudder system will have tiny movements. At this time, the host cannot locate the fault and generally thinks that the rudder system has a fault. We need to go to the test field to cooperate with the host to investigate the problem, consuming manpower and material resources. Specifically, the reason for the tiny stroke misoperation of the rudder system in the critical low-voltage state is that the timing of the secondary power supply of the internal control power and the driving power of the rudder system will be chaotic when powering off. The acceleration of the drop of the secondary control voltage is significantly greater than that of the secondary driving voltage, and the two voltages are not grounded together. The secondary control voltage mainly supplies power to the CPU of the rudder system, and the secondary driving voltage mainly supplies power to the driving part of the rudder system. When powering off in the critical low-voltage situation, the timing difference between the control and driving secondary power supplies is relatively large. Measured with an isolation oscilloscope, there is a delay of 8ms. This will cause the control part to have powered off, while the driving part has not completely powered off. If the PWM frequency of the rudder system is 10K, it means that after the control power has powered off, the driving power will take another 80 PWM cycles to completely power off. This period of delay will cause the PWM wave of the driving part to act on the servo for a short period of time, so the servo will move within a small angle range (this angle will vary depending on the speed of different servos). When powering off under normal voltage (non-critical low-voltage state), the timing difference between the secondary power supply of the control power and the secondary power supply of the driving power is relatively small, only differing by 0.5ms, so it can be ignored.

[0004] The reasons why the rudder system cannot exhibit actions within a small angle range are as follows: When designing the transmission system for some drones, a reduction ratio coefficient is designed between the output rocker of the servo and the connecting rod. Sometimes, this coefficient magnifies this angle at the rudder surface, causing problems such as rudder blade jitter or jamming. Therefore, the drone rudder system does not allow the occurrence of low battery voltage problems, which may lead to structural jamming or jitter.

[0005] Currently, most rudder systems rarely collect the input battery voltage and default the input to the normal voltage range. In the few cases where it is necessary to collect the on-board power supply, a Hall voltage sensor is used to achieve this. Specifically, the on-board voltage passes through a power resistor to convert the voltage signal into a current signal, which flows into the positive input terminal of the Hall voltage sensor. At the output terminal of the sensor, the output current signal is again converted into a voltage signal through a resistor, and then passes through a voltage follower and two-stage inverting amplifiers to obtain the required voltage detection value. With such a design, the measured signal is frequently converted, and the isolation effect between the control power and the on-board power is not good. At the same time, it requires many components, occupies a large space, and has a high cost. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problem that when the battery voltage for the dedicated power supply of the electric rudder system of an existing drone is relatively low, the rudder system may malfunction with a small stroke. A power management system for a drone rudder system is provided, which can avoid malfunctioning under low voltage while reducing costs and the space required for voltage monitoring.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A power management system for a drone rudder system is mainly provided, including a hardware part and a software part. The hardware part includes a battery voltage monitoring and judgment circuit, a main control chip, and an upper computer connected in sequence. The software part includes a fault logic determination module, a communication module, and a fault removal module. The fault software logic determination module is used to adopt corresponding control strategies when the battery voltage exceeds the threshold range. The communication module is used for the main control chip to report the fault status to the upper computer. The fault removal module is used for the main control chip to determine the working state of the rudder system according to the voltage state.

[0009] The fault software logic determination module is used to adopt corresponding control strategies when the battery voltage exceeds the threshold range, including:

[0010] When the battery voltage is greater than the threshold, the main control chip determines that the battery is normal. When the battery voltage is less than the threshold, the main control chip determines that the battery is abnormal.

[0011] The main control chip determines the working state of the rudder system according to the voltage state, including:

[0012] When the main control chip determines that the battery is normal, the rudder system works normally. When the main control chip determines that the battery is abnormal, the operation of the rudder system is disconnected.

[0013] As a preferred option, for a power management system of a drone rudder system, the battery voltage monitoring and judgment circuit includes a reverse resistor, a voltage stabilizing diode, a logic switch, and a pull-up resistor connected in sequence.

[0014] As a preferred option, for a power management system of a drone rudder system, the logic switch is an optocoupler.

[0015] As a preferred option, for a power management system of a drone rudder system, when the voltage is greater than the set threshold, the voltage stabilizing diode breaks down, the reverse resistor becomes smaller, the current increases, and it is stabilized at the set threshold. The optocoupler is in a saturated conduction state and outputs a low level to the main control chip.

[0016] As a preferred option, for a power management system of a drone rudder system, when the battery voltage is greater than the threshold, the main control chip determines that the battery is normal, including:

[0017] When the main control chip continuously receives a low level for a period of time, it determines that the battery is normal.

[0018] As a preferred option, for a power management system of a drone rudder system, when the voltage is less than the set threshold, the reverse leakage current of the voltage stabilizing diode is small, the dynamic resistance is large, the optocoupler is not conducting, and at this time, the output end of the optocoupler outputs a high level to the main control chip through the pull-up resistor.

[0019] As a preferred option, for a power management system of a drone rudder system, the type selection of the voltage stabilizing diode is selected according to the battery output range.

[0020] As a preferred option, for a power management system of a drone rudder system, the threshold is selected according to the type selection of the voltage stabilizing diode.

[0021] As a preferred option, for a power management system of a drone rudder system, the main control chip includes a CPU and a minimum peripheral unit, and the CPU is an FPGA, a DSP, or a single-chip microcomputer.

[0022] As a preferred option, for a power management system of a drone rudder system, when the main control chip determines that the battery is abnormal and disconnects the operation of the rudder system, it includes:

[0023] The main control chip turns off the PWM control signal of the steering gear and disconnects the steering gear.

[0024] It should be further noted that the technical features corresponding to the above system options can be combined or replaced with each other without conflict to form a new technical solution.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] (1) The present invention detects the output voltage of the on-board battery in real time through a battery voltage monitoring and judgment circuit, and quickly determines whether the on-board battery is supplying power normally through a main control chip and a fault software logic judgment module. When the on-board battery is abnormal, the main control chip timely controls the working state of the rudder system, and cooperates with a fault removal module to cut off the rudder system when the battery voltage is low, avoiding the fault of misoperation with a small stroke of the rudder system when the UAV battery voltage is low. At the same time, it does not require too many signal conversion devices, saving costs and reducing the space required for voltage monitoring.

[0027] (2) In one example, the main control chip communicates with an upper computer (flight control computer) through a communication module, enabling the rudder system to report faults to the flight control computer when the on-board battery is in a low voltage state, allowing the flight control computer to quickly locate the fault; at the same time, making timely judgments to avoid misoperations in a fault state and ensuring the correctness of power supply.

[0028] (3) In one example, the circuit design of the system is simple in structure, low in cost, high in reliability, and complete in function, improving the safety and maintainability of the host system, and also improving the supportability and safety of the supporting rudder system.

[0029] (4) In one example, an optocoupler is selected as the logic switch. Since the internal power supplies of the rudder system are designed to be isolated from each other due to electromagnetic compatibility reasons, that is, the primary power supply and the secondary power supply control parts are isolated, general hardware logic switches such as triodes and MOS transistors cannot meet the isolation requirements. The two ends of the optocoupler are isolated from each other, which can isolate the battery ground and the control ground, avoiding crosstalk between grounds, and is very suitable for the requirements of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic circuit structure diagram of a power management system for a UAV rudder system shown in an embodiment of the present invention;

[0031] Figure 2 is a flowchart of low-voltage fault logic determination shown in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. 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.

[0033] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it 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, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] In an exemplary embodiment, on the basis of making full use of the closed-loop control of the traditional electric rudder system, the present invention adds a part of software and hardware design to implement functions, and provides a power management system for an unmanned aerial vehicle (UAV) rudder system, including a hardware part and a software part. The hardware part includes a battery voltage monitoring and judging circuit, a main control chip, and a host computer connected in sequence, etc. The software part includes a fault logic determination module, a communication module, a fault removal module, etc. The fault software logic determination module is used to adopt corresponding control strategies when the battery voltage exceeds the threshold range; the communication module is used for the main control chip to report the fault status to the host computer; the fault removal module is used for the main control chip to determine the working state of the rudder system according to the voltage state.

[0036] The fault software logic determination module is used to adopt corresponding control strategies when the battery voltage exceeds the threshold range, including:

[0037] When the battery voltage is greater than the threshold, the main control chip determines that the battery is normal; when the battery voltage is less than the threshold, the main control chip determines that the battery is abnormal.

[0038] The main control chip determines the working state of the rudder system according to the voltage state, including:

[0039] When the main control chip determines that the battery is normal, the rudder system works normally; when the main control chip determines that the battery is abnormal, the working of the rudder system is disconnected.

[0040] Specifically, referring to Figure 1 , the battery voltage monitoring and judging circuit includes a reverse resistor, a voltage stabilizing diode, a logic switch, and a pull-up resistor connected in sequence. The main control chip includes a CPU and its peripheral minimum unit. The CPU is an FPGA, a DSP, or a single-chip microcomputer. The communication module is connected to the CPU through an RS422 communication interface. Among them, the logic switch is preferably an optocoupler. The working process of a power management system for an unmanned aerial vehicle rudder system will be specifically described below in combination with Figure 2 :

[0041] When the voltage is greater than the set threshold, the zener diode breaks down, the reverse resistance becomes smaller, the current increases, and the voltage stabilizes at the set threshold. The optocoupler is in a saturated conduction state, and the output voltage is very low, only 0.x volts, so it is a low level. This low level is output to the CPU. After the CPU continuously receives it for a period of time (the time can be set according to the software), it is determined to be in a normal working state, and the steering gear system normally outputs a PWM control signal; when the voltage is less than the set threshold, the reverse leakage current of the zener diode is very small, the dynamic resistance is very large, the optocoupler is not conducting, and at this time, there is a pull-up resistor at the output end of the optocoupler, so a high level is output to the CPU. After the CPU receives this high level, it determines that the power supply of the steering gear system is abnormal and turns off the PWM control signal. At this time, the steering gear system is not under force and is in a follow-up state, and will not be damaged due to further misoperation. At the same time, the CPU returns the status to the flight control computer (i.e., the upper computer in the figure) through the communication interface to quickly locate the fault.

[0042] It should be noted that: 1. The threshold for fault determination is comprehensively considered based on the state of the battery and the primary power supply range of the steering gear system. For example, the battery output range is 28 ± 6V, and the voltage input range of the steering gear system is 18 - 36V (this is an example but not limited to this range). This range determines the selection of the zener diode during design. Specifically, it is determined by the U Z value of the zener diode. Reasonably selecting the U Z value can determine the threshold for determining whether the battery is low voltage.

[0043] 2. The reason for choosing the optocoupler as the logic switch in the present invention: The internal power supply of the steering gear system is designed to be isolated from each other due to electromagnetic compatibility reasons, that is, the primary power supply and the secondary power supply control part are isolated. General hardware logic switches such as triodes and MOS tubes cannot meet the isolation requirements. The two ends of the optocoupler are isolated from each other, which can isolate the battery ground and the control ground and avoid crosstalk between the grounds, which is very suitable for the requirements of this design.

[0044] Through the design of the present invention, the monitoring and fault reporting of the on-board power supply status of the steering gear system are satisfied, which is beneficial for the host system to locate faults in the slave system. At the same time, the steering gear system is designed with fault removal to avoid further misoperation.

[0045] The above specific implementation manners are detailed descriptions of the present invention. It cannot be determined that the specific implementation manners of the present invention are only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions and substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A power management system for a drone rudder system, characterized in that, It includes a hardware part and a software part. The hardware part includes a battery voltage monitoring and judging circuit, a main control chip, and a host computer connected in sequence. The software part includes a fault logic determination module, a communication module, and a fault removal module; The fault software logic determination module is used to adopt corresponding control strategies when the battery voltage exceeds the threshold range. The communication module is used for the main control chip to report the fault status to the host computer. The fault removal module is used for the main control chip to determine the working state of the steering gear system according to the voltage state; The fault software logic determination module is used to adopt corresponding control strategies when the battery voltage exceeds the threshold range, including: When the battery voltage is greater than the threshold, the main control chip determines that the battery is normal. When the battery voltage is less than the threshold, the main control chip determines that the battery is abnormal; The main control chip determines the working state of the steering gear system according to the voltage state, including: When the main control chip determines that the battery is normal, the steering gear system works normally. When the main control chip determines that the battery is abnormal, the working of the steering gear system is disconnected; The battery voltage monitoring and judging circuit includes a reverse resistor, a voltage stabilizing diode, a logic switch, and a pull-up resistor connected in sequence. The logic switch is an optocoupler. When the voltage is greater than the set threshold, the voltage stabilizing diode breaks down, the reverse resistor becomes smaller, the current increases, and it is stabilized at the set threshold. The optocoupler is in a saturated conduction state and outputs a low level to the main control chip.

2. The power management system of a drone rudder system according to claim 1, characterized in that The situation that when the battery voltage is greater than the threshold, the main control chip determines that the battery is normal includes: When the main control chip continuously receives a low level for a period of time, it determines that the battery is normal.

3. The power management system of a drone rudder system according to claim 1, characterized in that When the voltage is less than the set threshold, the reverse leakage current of the voltage stabilizing diode is small, the dynamic resistance is large, the optocoupler is not conducting, and at this time, the output end of the optocoupler outputs a high level to the main control chip through the pull-up resistor.

4. The power management system of a drone rudder system according to claim 1, characterized in that, The type selection of the voltage stabilizing diode is selected according to the battery output range.

5. The power management system of a drone rudder system according to claim 3, characterized in that The threshold is selected according to the type selection of the voltage stabilizing diode.

6. The power management system of a drone rudder system according to claim 1, characterized in that, The main control chip includes a CPU and a minimum peripheral unit. The CPU is an FPGA, a DSP, or a single-chip microcomputer.

7. The power management system for the drone rudder system according to claim 1, characterized in that, The situation that when the main control chip determines that the battery is abnormal, the working of the steering gear system is disconnected includes: The main control chip turns off the PWM control signal of the steering gear and disconnects the steering gear.

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