Patent Description:
A drone initially used for military purposes refers to an unmanned aerial vehicle or a helicopter-shaped flying vehicle that flies by induction of radio waves without a human pilot or operator being on board. Recently, drones are being widely used for military and commercial purposes, and research has been actively conducted on drones to be used for various purposes.

For example, the <CIT>, discloses a drone. <CIT> discloses an electrical remote-control and remote-power flying saucer. <CIT> discloses a quadrocopter. <CIT> discloses an unmanned aircraft (drone). <CIT> discloses an unmanned aerial vehicle. <CIT> discloses a gyro-stabilized air vehicle. <CIT> discloses a horizontal attitude stabilization device for disc air vehicle.

According to the present invention, there is provided a drone fall prevention system as defined in claim <NUM>.

When the drone fails, the controller may stabilize a posture of the main body by driving the first rotation stabilizing portion, to prevent an occurrence of a tumbling phenomenon.

Also, the controller may control the driving of the first rotation stabilizing portion so that an error between an angular velocity value for a preset yaw axis and an angular velocity value for an actual yaw axis may be minimized.

In addition, the drone fall prevention system may further include a second rotation stabilizing portion disposed on a bottom surface of the main body of the drone. The second rotation stabilizing portion may include a propeller, and a motor configured to provide a rotational force to the propeller, and may be configured to generate an angular velocity with respect to the yaw angle of the main body and a thrust force for the main body at the same time.

According to example embodiments, a drone and a drone fall prevention system may prevent a tumbling phenomenon from occurring when the drone falls due to a failure of the drone during flight, thereby stabilizing a posture of the falling drone.

According to example embodiments, a drone and a drone fall prevention system may delay the drone by delaying a falling speed when the drone falls due to a failure of the drone during flight.

According to example embodiments, a drone and a drone fall prevention system may secure a time required to deploy a parachute by delaying a falling speed when the drone falls due to a failure of the drone during flight.

According to example embodiments, a drone and a drone fall prevention system may maintain an altitude by additionally generating a thrust force for a translational motion when the drone falls due to a failure of the drone during flight.

Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings.

The following description is provided according to one of various aspects of the example embodiments, and may constitute a part of detailed description of the example embodiments.

However, in describing an example embodiment, detailed description of known functions or configurations will be omitted for the sake of clarity and conciseness.

In addition, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation.

<FIG> illustrates an example of a drone including a first rotation stabilizing portion according to an example embodiment, and <FIG> illustrates an operating principle of a first rotation stabilizing portion according to an example embodiment. <FIG> illustrates an example of a drone including a first rotation stabilizing portion according to a modified example embodiment, and <FIG> illustrates an operating principle of a first rotation stabilizing portion according to a modified example embodiment. <FIG> illustrates a drone including a second rotation stabilizing portion according to an example embodiment, and <FIG> illustrates an operation sequence of a drone according to an example embodiment. <FIG> and <FIG> illustrate effects of a drone according to an example embodiment.

Referring to <FIG>, a drone <NUM> according to an example embodiment includes a main body <NUM>, a propulsion portion <NUM> disposed outside the main body <NUM> to generate a thrust force, a first rotation stabilizing portion <NUM> disposed on a top surface of the main body <NUM> to generate an angular velocity with respect to a yaw axis Yaw of the main body, and a controller <NUM> configured to control driving of the first rotation stabilizing portion <NUM>. When the propulsion portion <NUM> fails, the controller <NUM> is configured to stabilize a posture of the main body <NUM> by driving the first rotation stabilizing portion <NUM>, to prevent an occurrence of a tumbling phenomenon.

For example, the controller <NUM> may be configured to drive the first rotation stabilizing portion <NUM> so that an error between an angular velocity value for a preset yaw axis and an angular velocity value for an actual yaw axis may be minimized. In this example, a PID control may be used as a control logic of the controller <NUM>.

Specifically, the first rotation stabilizing portion <NUM> is disposed on the top surface of the main body <NUM>, and includes a propeller <NUM>, a motor <NUM> disposed below the propeller <NUM> to provide a rotational force to the propeller, and a shielding element <NUM> disposed above the propeller to prevent a thrust force from being generated by a rotation of the propeller. Here, a rotation axis of the motor <NUM> needs to be aligned with the yaw axis of the body <NUM>.

Referring to <FIG>, the first rotation stabilizing portion <NUM> according to an example embodiment including the above configuration rotates the drone using a force of wind in a direction orthogonal to the yaw axis, the force of wind being generated when the propeller <NUM> rotates. For example, as shown in (a) of <FIG>, when the propeller <NUM> rotates in a clockwise direction, a rotational force may be generated in a positive direction with respect to the yaw axis of the main body by a force F of wind. In addition, as shown in (b) of <FIG>, when the propeller <NUM> rotates in a counterclockwise direction, a rotational force may be generated in a negative direction with respect to the yaw axis of the main body by a force F' of wind.

Referring to <FIG>, in an example not in accordance with the present invention, the drone may include a first rotation stabilizing portion <NUM>' according to a modified example embodiment. Here, a main body, a propulsion portion, and a controller may be all the same as the above-described configurations, and the first rotation stabilizing portion <NUM>' may be obtained by modification.

The first rotation stabilizing portion <NUM>' may be disposed inside the main body <NUM>, and may include a flywheel <NUM>', and a motor <NUM>' disposed below the flywheel to provide a rotational force to the flywheel.

Here, a rotation axis of the motor <NUM>' may be set to be parallel to a yaw axis of the main body. In other words, unlike the above-described first rotation stabilizing portion <NUM>, in the first rotation stabilizing portion <NUM>' according to the modified example embodiment, the rotation axis of the motor may not need to be aligned with the yaw axis of the main body and may be freely placed inside the main body such that the rotation shaft of the motor is parallel to the yaw axis of the main body.

Referring to <FIG>, in an example not in accordance with the present invention, the first rotation stabilizing portion <NUM>' may rotate the drone using a reaction force generated when the flywheel <NUM>' rotates.

In addition, referring to <FIG>, the drone <NUM> may further include a second rotation stabilizing portion <NUM> disposed on a bottom surface of the main body <NUM>. The second rotation stabilizing portion <NUM> may include a propeller <NUM>, and a motor <NUM> configured to provide a rotational force to the propeller. In other words, the second rotation stabilizing portion <NUM> does not include a shielding element, unlike the first rotation stabilizing portion <NUM>. Accordingly, the second rotation stabilizing portion <NUM> may generate an angular velocity with respect to the yaw axis Yaw of the main body and a thrust force for the main body at the same time.

Based on the above configuration of the second rotation stabilizing portion <NUM>, a rotational momentum and a thrust force for a translational motion may be generated at the same time, and thus it may be possible to utilize the thrust force added by the second rotation stabilizing portion <NUM> as a thrust force to maintain an altitude which is insufficient due to a failure.

In addition, the drone <NUM> may include a plurality of propulsion portions. For example, when one of the plurality of propulsion portions fails, the controller <NUM> may stop driving a propulsion portion that is disposed symmetrically with the failed propulsion portion based on the main body.

Also, the drone <NUM> may further include a parachute (not shown) or an airbag (not shown) accommodated in the main body.

An operation sequence of a drone with the above configuration is shown in <FIG>.

For example, when one of a plurality of propulsion portions fails, a failure of a propulsion portion may be detected based on a sensor value and posture information of the drone. When the failure is detected, power of the failed propulsion portion may be cut off, and power of a propulsion portion disposed symmetrically with the failed propulsion portion may be cut off. When the power is cut off, a controller may drive a rotation stabilizing portion to prevent a tumbling phenomenon from occurring in the drone. A constant angular velocity with respect to a yaw axis of a main body of the drone may be maintained by an operation of the rotation stabilizing portion, and accordingly the drone may maintain a horizontal posture. In addition, when whether the posture is stable with respect to a roll axis and a pitch axis of the drone is determined, a parachute or an airbag may be deployed before the drone lands on the ground. Alternatively, soft landing of the drone may be induced by slowly decreasing a command altitude.

An effect of preventing the drone from falling by the operation of the rotation stabilizing portion may be confirmed through experimental data of <FIG> and <FIG>.

Referring to <FIG>, when the controller performs control by inputting a soft landing command to the rotation stabilizing portion, an altitude of the drone that fails or breaks down may be gradually lowered to make a soft landing. On the other hand, referring to <FIG>, it may be confirmed that when the controller controls only the posture, instead of inputting a separate soft landing command to the rotation stabilizing portion, the altitude of the drone that fails or breaks down may be maintained at a predetermined level.

The drone with the above-described configuration may prevent a tumbling phenomenon from occurring when the drone falls due to a failure of the drone during flight, to stabilize the posture of the falling drone, and may be delayed by delaying the falling speed.

In addition, the drone may secure a time required to deploy a parachute by delaying the falling speed, and may maintain the altitude at a predetermined level by additionally generating a thrust force for a translational motion.

A drone fall prevention system according to an example embodiment may be selectively attached to or detached from the drone, and may control a movement of the drone when the drone falls due to a failure of the drone. The drone fall prevention system includes a first rotation stabilizing portion that is disposed on the upper surface of the main body to generate an angular velocity with respect to the yaw axis of the main body, and a controller configured to drive the first rotation stabilizing portion.

When the drone fails, the controller is configured to stabilize a posture of the main body by driving the first rotation stabilizing portion, to prevent an occurrence of a tumbling phenomenon.

In addition, the controller may control the driving of the first rotation stabilizing portion so that an error between an angular velocity value for a preset yaw axis and an angular velocity value for an actual yaw axis may be minimized.

Here, the first rotation stabilizing portion is disposed on the top surface of the main body, and includes a propeller, a motor disposed below the propeller to provide a rotational force to the propeller, and a shielding element disposed above the propeller to prevent a thrust force from being generated by a rotation of the propeller. Also, a rotation shaft of the motor is aligned with the yaw axis of the main body, and the first rotation stabilizing portion is configured to rotate the drone using a force of wind in a direction orthogonal to the yaw axis, the force of wind being generated when the propeller rotates.

In an illustrative example not covered by the scope of the appended claims, the first rotation stabilizing portion may disposed inside the main body, and may include a flywheel, and a motor disposed below the flywheel to provide a rotational force to the flywheel. Here, a rotation shaft of the motor may be set to be parallel to the yaw axis of the main body. The first rotation stabilizing portion may be configured to rotate the drone using a reaction force generated when the flywheel rotates.

Claim 1:
A drone fall prevention system for controlling a movement of a drone (<NUM>) when the drone falls due to a failure of the drone, and comprising:
a first rotation stabilizing portion (<NUM>) configured to be disposed on a top surface of a main body (<NUM>) of the drone to generate an angular velocity with respect to a yaw axis of the main body; and
a controller (<NUM>) configured to drive the first rotation stabilizing portion (<NUM>),
wherein when the drone fails, the controller is configured to stabilize a posture of the main body (<NUM>) by driving the first rotation stabilizing portion (<NUM>), to prevent an occurrence of a tumbling phenomenon,
wherein the first rotation stabilizing portion (<NUM>) comprises:
a propeller (<NUM>);
a motor (<NUM>) disposed below the propeller to provide a rotational force to the propeller (<NUM>), wherein a rotation shaft of the motor is configured to be aligned with the yaw axis of the main body; and
a shielding element (<NUM>) disposed above the propeller to prevent a thrust force from being generated by a rotation of the propeller, and
wherein the first rotation stabilizing portion (<NUM>) is configured to rotate the drone (<NUM>) using a force of wind in a direction orthogonal to the yaw axis, the force of wind being generated when the propeller (<NUM>) rotates.