Unmanned aerial vehicle and fail-safe method thereof

An unmanned aerial vehicle and a fail-safe method thereof are provided. The unmanned aerial vehicle includes at least one actuator, a failure processing circuit, and a flight controller. The actuator is configured to drive the flight behavior of the unmanned aerial vehicle. The failure processing circuit is configured to: define a corresponding relationship between the multiple failure states and the multiple protection measures, wherein each protection measure is respectively defined with a priority level and each protection measure is used to correspondingly change the flight behavior of the unmanned aerial vehicle; determine multiple current failure states when the flight behavior takes place; and select, according to the corresponding relationship, the selected protection measure having the highest priority level among the protection measures corresponding to the current failure state. The flight controller is used to change the flight behavior of the unmanned aerial vehicle according to the selected protection measures.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of China application serial no. 201910102906.7, filed on Feb. 1, 2019. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The present disclosure relates to an unmanned flight technology, and more particularly to an unmanned aerial vehicle and a fail-safe method thereof.

Description of Related Art

A drone includes subsystems such as sensors, power sources, and navigation device. Each subsystem is composed of multiple components to operate together. Any failure of one component can cause safety concerns. The concept of failure-protection or fail-safe is to avoid or reduce the damage caused by a specific failure of the subsystem.

The current failure-protection of a drone is, for example, switching to a backup control module or directly shutting down the power source when a failure is detected. However, such an approach is not practical. For example, if switched to the backup control module when the failure is detected, the function of failure-protection cannot be performed when the failed component is the power source itself. If the power source is directly shut down when the failure is detected, it is very likely to cause damage or result in a greater loss.

SUMMARY OF THE DISCLOSURE

The disclosure provides an unmanned aerial vehicle and a fail-safe method thereof, which can take the most appropriate protection measures when a failure occurs.

The objectives and advantages of the disclosure may be further understood in the technical features disclosed in the disclosure.

To achieve one or a part or all the objectives or other objectives, an embodiment of the present disclosure provides an unmanned aerial vehicle that includes at least one actuator, a failure processing circuit, and a flight controller. The at least one actuator is configured to drive the flight behavior of the unmanned aerial vehicle. The failure processing circuit is configured to: define a corresponding relationship between a plurality of failure states and a plurality of protection measures, wherein each protection measure is respectively defined with a priority level and each protection measure is configured to correspondingly change the flight behavior of the unmanned aerial vehicle; determine a plurality of current failure states when the flight behavior takes place, wherein the plurality of defined failure states include the plurality of current failure states; and select, according to the corresponding relationship, the selected protection measure having the highest priority level among the protection measures corresponding to the current failure state. The flight controller is coupled to the actuator and the failure processing circuit and is configured to change the flight behavior of the unmanned aerial vehicle according to the selected protection measure.

To achieve one or a part or all the objectives or other objectives, an embodiment of the present disclosure provides a fail-safe method for an unmanned aerial vehicle, including the steps of: defining a corresponding relationship between a plurality of failure states and a plurality of protection measures, wherein each protection measure is respectively defined with a priority and each protection measure is configured to correspondingly change the flight behavior of the unmanned aerial vehicle; determining a plurality of current failure states when the flight behavior of the unmanned aerial vehicle takes place, wherein the defined failure states include the plurality of current failure states; selecting, according to the corresponding relationship, the selected protection measure having the highest priority level among the protection measures corresponding to the current failure state; and changing the flight behavior of the unmanned aerial vehicle according to the selected protection measure.

In an embodiment of the disclosure, the fail-safe method further includes the step of: stopping changing the flight behavior according to the protection measure with lower priority other than the selected protection measure.

Based on the above, the unmanned aerial vehicle and the fail-safe method thereof in the embodiment of the present disclosure define a corresponding relationship between a plurality of failure states and a plurality of protection measures, and each protection measure is respectively defined with a priority level. When multiple failure states occur at the same time, the protection measure having the highest priority level among the plurality of protection measures corresponding to the plurality of currently occurred failure states is selected. Accordingly, no matter whether multiple failure states occur simultaneously or alternately, the most appropriate protection measures can be taken according to the defined priority levels to minimize damage and loss.

In order to make the aforementioned features and advantages of the disclosure more comprehensible, embodiments accompanying figures are described in detail below.

DESCRIPTION OF EMBODIMENTS

FIG. 1is a block diagram of an unmanned aerial vehicle according to an embodiment of the present disclosure.

Referring toFIG. 1, an unmanned aerial vehicle100is an aircraft that flies without human operators being present in the aircraft and includes an actuator110, a flight controller (FC)120, a failure processing circuit130, a communication module140, a positioning module150, and an attitude sensor160.

The actuator110is configured to drive the flight behavior of the unmanned aerial vehicle100. For example, the actuator110includes a power source (e.g., a motor), an electronic speed controller, and a rotor, etc., capable of driving the flight behavior of the unmanned aerial vehicle100according to the electronic signals from the flight controller120, such as taking-off, turning, shifting, landing, etc. Herein, as long as the actuator110(e.g., power source) begins to operate, no matter whether or not the unmanned aerial vehicle100is off the ground, a flight behavior has taken place. Moreover, the present disclosure provides no limitation to the number of actuators110, and depending on the design, the unmanned aerial vehicle100may include one or more sets of actuators110.

The flight controller120is coupled to the actuator110for generating and transmitting an electronic signal to the actuator110to control the operation of the actuator110, and to further control the flight behavior of the unmanned aerial vehicle100. For example, the flight controller120determines how to control the navigation of the unmanned aerial vehicle100or adjusts the attitude of the unmanned aerial vehicle100, etc., according to the messages efrom other components of the unmanned aerial vehicle100. The messages is, for example, remote control signals from a communication module140, location information from a positioning module150, or acceleration data from the attitude sensor160, but the disclosure is not limited thereto.

The failure processing circuit130is coupled to the flight controller120and other components of the unmanned aerial vehicle100, including the actuator110, the communication module140, the positioning module150, the attitude sensor160, and the like. The failure processing circuit130is configured to detect a failure state of the unmanned aerial vehicle100, and determine a protection measure according to the detected failure state of the unmanned aerial vehicle100, and then notify the flight controller120of the determined protection measure in order for the flight controller120to control the flight behavior of the unmanned aerial vehicle100accordingly. The types of failure states that the failure processing circuit130can detect include component malfunctions, abnormal attitude, or environmental anomalies, and the present disclosure provides no limitation thereto. For example, the failure processing circuit130can be a central processing unit (CPU), or other programmable general-purpose or specific-purpose microprocessor, a digital signal processor (DSP), a programmable controller, application specific integrated circuits (ASIC), programmable logic device (PLD), field programmable gate array (FPGA), or the like or a combination of these devices, etc., the disclosure is not limited thereto.

In addition, it should be noted that the failure processing circuit130may be a circuit or a chip independent of the flight controller120, or may be integrated into a single circuit or a chip with the flight controller120. The disclosure is not limited thereto.

The communication module140is configured to receive a remote control signal from an external device. For example, the communication module140, for example, includes a wireless transmission module such as a WiFi module or a radio transceiver module, and can be used to receive the remote control signal from the external device such as a smartphone, a tablet PC, a remote controller (RC), or a ground control station (GCS), but the disclosure is not limited thereto.

The positioning module150is configured to obtain location information of the unmanned aerial vehicle100. For example, the positioning module150may be a global positioning system (GPS) receiver based on satellite positioning system, and can receive the current latitude and longitude of the unmanned aerial vehicle100, but the disclosure is not limited thereto.

The attitude sensor160is configured to sense the current attitude of the unmanned aerial vehicle100. For example, the attitude sensor160includes one or a combination of a tri-axial acceleration sensor and a gyroscope, and the data obtained by these above components can reflect the current attitude of the unmanned aerial vehicle100, including, for example, a yaw angle, a roll angle and a pitch angle.

FIG. 2is a flow chart of a fail-safe method according to an embodiment of the present disclosure.

Referring toFIG. 1andFIG. 2, first, the failure processing circuit130defines a corresponding relationship between a plurality of failure states and a plurality of protection measures (step S201), wherein the protection measures are used to change the flight behavior of the unmanned aerial vehicle100, and the failure processing circuit130will define different priority levels for each of the protection measures.

Specifically, the remaining capability of the unmanned aerial vehicle100is different when different failure states occur, and thus the possible damage or severity may be different. Based on the above, for a more severe failure state, the failure processing circuit130defines a higher priority level for the corresponding protection measure.

For example, the corresponding relationship between a plurality of failure states and a plurality of protection measures and the priority level of each protection measure are shown in Table 1 below.

Specifically, when the failure state of the unmanned aerial vehicle100detected by the failure processing circuit130is a malfunction of the communication module130, although the unmanned aerial vehicle100cannot be remotely controlled by an external device, the unmanned aerial vehicle100still has normal flight and navigating capability. Therefore, the protection measure corresponding to the malfunction of the communication module140is return the flight of the unmanned aerial vehicle100, that is, the current flight behavior of the unmanned aerial vehicle100is changed to fly to the return position. The return position is, for example, preset in a memory (not shown) of the unmanned aerial vehicle100, which may be the same as or different from the take-off position, and the present disclosure is not limited thereto.

When the failure state of the unmanned aerial vehicle100detected by the failure processing circuit130is malfunction of the positioning module150or the actuator110, the unmanned aerial vehicle100loses its direction on this occasion and no longer has navigating capability and cannot fly to the return position. Therefore, the protection measure corresponding to the malfunction of the positioning module150or the actuator110is in-situ landing, and the priority level corresponding the in-situ landing is higher than the priority level of the returning flight.

When the failure state of the unmanned aerial vehicle100detected by the failure processing circuit130is abnormality of the current attitude, the actuator110is unable to balance the unmanned aerial vehicle100or is severely failed. On this occasion, the unmanned aerial vehicle100may be in rotation or rolling. In such state, if power is continuously supplied to the unmanned aerial vehicle100, a great damage is likely to be caused to surrounding environment. Therefore, the protection measure corresponding to the current abnormal attitude of the unmanned aerial vehicle100is to turn off the actuator110, and the priority level of turning off the actuator110is higher than the priority level corresponding to the in-situ landing.

It should be noted that the above-described corresponding relationships and priority levels are merely illustrative and are not intended to limit the disclosure. In addition, the present disclosure provides no limitation to the definitions of the above-mentioned corresponding relationships and the priority levels, and the definitions may be pre-written in the failure processing circuit, or may be defined by the user.

When the flight behavior of the unmanned aerial vehicle100takes place, the failure processing circuit130detects the failure state of the unmanned aerial vehicle100(step S203), and the detected failure state is also referred to as the current failure state.

For example, the failure processing circuit130can determine whether the communication module140is malfunctioned according to the signal state between the communication module140and the external device; the failure processing circuit130can determine whether the actuator110is malfunctioned according to the signal from the actuator110, such as abnormality of rotation speed and so on; the failure processing circuit130can determine whether the positioning module150is malfunctioned according to the signal from the positioning module150; and the failure processing circuit130can determine whether the current attitude of the unmanned aerial vehicle100is abnormal according to the sensing data from the attitude sensor160. For example, when the roll angle of the unmanned aerial vehicle100is greater than a preset roll angle threshold or the pitch angle is greater than a preset pitch angle threshold, the failure processing circuit130determines that the current attitude of the unmanned flight vehicle100is abnormal. However, the present disclosure provides no limitation to the specific determining method of the failure state, which can be set by persons skilled in the art as needed.

If there is one current failure state, the failure processing circuit130selects the protection measure corresponding to the current failure state as the selected protection measure according to the corresponding relationship (step S205), and then notifies the flight controller120of the selected protection measure.

For example, if the malfunction of the communication module140detected by the failure processing circuit130is the only one current failure state, the corresponding “return flight” is selected from the corresponding relationship between the failure state and the protection measure as the selected protection measure.

If there are multiple current failure states, the failure processing circuit310selects the selected protection measure with the highest priority level among the plurality of protection measures corresponding to the plurality of current failure states according to the previously defined corresponding relationship (step S207), and then notifies the flight controller120of the selected protection measure.

For example, if the failure processing circuit130detects two current failure states, namely malfunction of the communication module140and malfunction of the positioning module150, since the protection measure “in-situ landing” corresponding to the malfunction of the positioning module150has a higher priority level than the protection measure “return flight” corresponding to malfunction of the communication module140, such that the failure processing circuit130selects “in-situ landing” as the selected protection measure.

Finally, the flight controller120controls the flight behavior of the unmanned aerial vehicle100according to the selected protection measures (step S209).

For example, if the flight controller120receives the selected protection measure “return flight” from the failure processing circuit130during the flight of the unmanned aerial vehicle100toward the destination, the flight controller120will change the flight behavior of the unmanned aerial vehicle100according to the selected protection measure “return flight”, that is, the unmanned aerial vehicle100is controlled to fly to the return position according to the location information from the positioning module150. On this occasion, if another current failure state occurs, causing the flight controller120to receive the selected protection measure “in-situ landing” from the failure processing circuit130, the flight controller120will stop changing the flight behavior of the unmanned aerial vehicle100according to the protection measure “return flight” with lower priority level, and change the flight behavior of the unmanned aerial vehicle100according to the protection measure “in-situ landing” with higher priority level, such that the unmanned aerial vehicle100is landed in situ.

In this way, no matter whether multiple current failure states occur simultaneously or alternately, the failure processing circuit130can take the most appropriate protection measures according to the priority level to minimize damage and loss. Another embodiment will be described below to illustrate the fail-safe method from the perspective of the processing logic of the failure processing circuit130.

FIG. 3is a flow chart of a fail-safe method according to an embodiment of the present disclosure.

Referring toFIG. 1andFIG. 3, first, the failure processing circuit130determines whether the flight behavior of the unmanned aerial vehicle100has taken place (step S301).

For example, the failure processing circuit130can determine whether the actuator110(e.g., power source) of the unmanned aerial vehicle100has begun to operate. If the actuator110does not start to operate, it is determined that the flight behavior of the unmanned aerial vehicle100has not taken place; otherwise, it is determined that the flight behavior of the unmanned aerial vehicle100has taken place.

If the failure processing circuit130determines that the flight behavior of the unmanned aerial vehicle100has not taken place, it is detected whether there is a current failure state, and the flight behavior will be prohibited if any current failure state is detected.

For example, the failure processing circuit130determines whether the current attitude of the unmanned aerial vehicle100is normal (step S302), determines whether the actuator110and the positioning module150are both normal (step S303), and determines whether the communication module140is normal (step S304). If the failure processing circuit130determines that the current attitude of the unmanned aerial vehicle100, the actuator110, the positioning module150, and the communication module140are all normal, the flight behavior is allowed (step S305), that is, the notification of prohibiting the flight behavior is not issued to the flight controller120. On the other hand, if the failure processing circuit130determines that one of the current attitude of the unmanned aerial vehicle100, the actuator110, the positioning module150, and the communication module140is abnormal, the flight behavior is prohibited (step S306), for example, the notification of prohibiting the flight behavior is sent to the flight controller120to prevent the flight controller120from instructing the actuator110to operate. No matter whether the unmanned aerial vehicle100executes troubleshooting, the failure processing circuit130returns to step S301to continuously determine whether the flight behavior of the unmanned aerial vehicle100has taken place.

If the failure processing circuit130determines that the flight behavior of the unmanned aerial vehicle100has taken place, the protection measure with the highest priority level corresponding to the current failure state is taken when a current failure state is detected.

For example, the failure processing circuit130sequentially detects whether the failure state occurs according to the priority level of the corresponding protection measures, and directly takes a corresponding protection measure when detecting the failure state (i.e., the current failure state).

Referring toFIG. 3and Table 1 at the same time, since the protection measure corresponding to the current attitude anomaly has the highest priority, the failure processing circuit130first determines whether the current attitude of the unmanned aerial vehicle100is normal (step S307), and when it is determined that the current failure state is abnormality of the current attitude according to the corresponding relationship between the failure state and the protection measure, notify the flight controller120to turn off the actuator110(step S311).

Since protection measures corresponding to malfunction of the actuator110and malfunction of the positioning module150have high priority level, after the failure processing circuit130determines that the current attitude of the unmanned aerial vehicle100is normal, it is then determined whether the actuator110and the positioning module150are both normal (step S308). Moreover, when it is determined that the current failure state is that at least one of the actuator110and the positioning module150is malfunctioned according to the corresponding relationship between the failure state and the protection measure, the flight controller120is notified to control the unmanned aerial vehicle100to land in situ (step S312).

Since the priority level of the protection measure corresponding to the malfunction of the communication module140is the lowest, after the failure processing circuit130determines that current attitude of the unmanned aerial vehicle100, the actuator110, and the positioning module150are all normal. And then the failure processing circuit130determines whether the communication module140is normal (step S309). Moreover, when it is determined that the current failure state is malfunction of the communication module140according to the corresponding relationship between the failure state and the protection measure, the flight controller120is notified to control the unmanned aerial vehicle100to return, that is, to fly to the return position (step S313). After the unmanned aerial vehicle100turns off the actuator110(step S311), is landed in situ (step S312) or flies to the return position (step S313), no matter whether the unmanned aerial vehicle100executes troubleshooting, the failure processing circuit130returns to step S301to continuously determine whether the flight behavior of the unmanned aerial vehicle100has taken place.

If the failure processing circuit130does not detect any current failure state when the flight behavior takes place, the flight controller120is not notified, and the flight controller120controls the actuator110to continue the flight behavior of the unmanned aerial vehicle100(step S310).

Specifically, the failure processing circuit130may, for example, perform the flow of the embodiment ofFIG. 3at a particular frequency (for example, but not limited to, 3 times per second). As such, similar to the embodiment ofFIG. 2, no matter whether multiple current failure states occur simultaneously or alternately, the failure processing circuit130is able to take the most appropriate current protection measures based on priority level to minimize damage and loss.

In summary, the unmanned aerial vehicle and the fail-safe method thereof in the embodiment of the present disclosure define a corresponding relationship between a plurality of failure states and a plurality of protection measures, and set one priority for each of the protection measures. When multiple failure states occur at the same time, the protection measure with the highest priority level is selected among the multiple protection measures corresponding to the multiple failure states occurring at the moment. Accordingly, no matter whether multiple failure states occur simultaneously or alternately, the most appropriate protection measures can be taken according to the defined priority levels to minimize damage and loss.