Vertical take-off and landing aircraft and vertical take-off and landing aircraft control method
A vertical take-off and landing aircraft that includes AC motors, which drive fans that propel the aircraft, and a control device for controlling the AC motors adaptively based on a thrust control amount from an attitude controller. In particular, the drive controller performs switching to convert DC from a power source to three-phase AC at a predetermined frequency to be supplied to the AC motors. The drive controller reduces the control frequency of the three-phase AC to be applied to the AC motor to reduce the control resolution when the flight mode is switched from a vertical flight control mode to a horizontal flight control mode, in which the control amount to correct the external forces is smaller. Therefore, it is possible to reduce the power loss in the controller and thus the power consumption compared to conventional vertical take-off and landing aircrafts, in which the control resolution is always constant.
1. A vertical take-off and landing aircraft comprising:
a fan for propelling the vertical take-off and landing aircraft;
a driving device for electrically driving the fan; and
a control device for controlling the driving device adaptively to an external force, wherein:
the control device reduces a control resolution of a control amount that is applied to the driving device as the control amount to correct the external force decreases;
the control device reduces the control resolution of the control amount that is applied to the driving device as a speed component perpendicular to a ground surface is small relative to a speed component parallel to the ground surface;
the control device is selectively operable in a horizontal flight control mode to be selected when the speed component parallel to the ground surface is larger than the speed component perpendicular to the ground surface, or a vertical flight control mode to be selected when the speed component parallel to the ground surface is equal to or smaller than the speed component perpendicular to the ground surface or to be selected when the aircraft is stationary in air;
when the flight control mode is switched from the vertical flight control mode to the horizontal flight control mode, the control device reduces the control resolution of the control amount to be applied to the driving device compared to that in the vertical flight control mode;
when the flight control mode is switched from the horizontal flight control mode to the vertical flight control mode, the control device increases the control resolution of the control amount to be applied to the driving device compared to that in the horizontal flight control mode; and
when it is unidentifiable to which of the horizontal flight control mode and the vertical flight control mode switching has been made, the control device assumes that switching has been made from the horizontal flight control mode to the vertical flight control mode to increase the control resolution of the control amount applied to the driving device compared to that in the horizontal flight control mode.
2. The vertical take-off and landing aircraft according to claim 1 , wherein:
when the speed component parallel to the ground surface is equal to or larger than the speed component perpendicular to the ground surface, the control device reduces the control resolution of the control amount to be applied to the driving device as an amount of air that comes from sides of the craft body is smaller.
3. The vertical take-off and landing aircraft according to claim 1 , wherein:
the control resolution of the control amount that is applied to the driving device by the control device is a control frequency of the control amount to be applied to the driving device.
4. A vertical take-off and landing aircraft comprising:
a fan for propelling the vertical take-off and landing aircraft;
a driving device for electrically driving the fan;
a control device for controlling the driving device adaptively to an external force, wherein:
the control device reduces a control resolution of a control amount that is applied to the driving device as the control amount to correct the external force decreases;
the control device reduces the control resolution of the control amount that is applied to the driving device as a speed component perpendicular to a ground surface is small relative to a speed component parallel to the ground surface;
the control device is selectively operable in a horizontal flight control mode to be selected when the speed component parallel to the ground surface is larger than the speed component perpendicular to the ground surface, or a vertical flight control mode to be selected when the speed component parallel to the ground surface is equal to or smaller than the speed component perpendicular to the ground surface or to be selected when the aircraft is stationary in air;
when the flight control mode is switched from the vertical flight control mode to the horizontal flight control mode, the control device reduces the control resolution of the control amount to be applied to the driving device compared to that in the vertical flight control mode;
when the flight control mode is switched from the horizontal flight control mode to the vertical flight control mode, the control device increases the control resolution of the control amount to be applied to the driving device compared to that in the horizontal flight control mode; and
when a device provided in a craft body malfunctions, the control device assumes that switching has been made from the horizontal flight control mode to the vertical flight control mode to increase the control resolution of the control amount applied to the driving device compared to that in the horizontal flight control mode.
5. A vertical take-off and landing aircraft control method comprising:
identifying an external force that acts on a vertical take-off and landing aircraft;
determining a control amount adaptively in response to the external force; and
controlling an electric fan for propelling the vertical take-off and landing aircraft based on the control amount, wherein:
as the control amount determined adaptively in response to the external force is reduced, a control resolution of the control amount is also reduced;
as a speed component perpendicular to a ground surface is small relative to a speed component parallel to the ground surface, the control resolution of the control amount is reduced;
when the speed component parallel to the ground surface is larger than the speed component perpendicular to the ground surface, a horizontal flight mode is selected;
when the speed component parallel to the ground surface is equal to or smaller than the speed component perpendicular to the ground surface or when the aircraft is stationary in air, a vertical flight control mode is selected;
when the flight control mode is switched from the vertical flight control mode to the horizontal flight control mode, the control resolution of the control amount is reduced compared to that in the vertical flight control mode;
when the flight control mode is switched from the horizontal flight control mode to the vertical flight control mode, the control resolution of the control amount is increased compared to that in the horizontal flight control mode; and
when it is unidentifiable to which of the horizontal flight control mode and the vertical flight control mode switching has been made, switching made from the horizontal flight control mode to the vertical flight control mode is assumed and the control resolution of the control amount is increased compared to that in the horizontal flight control mode.