MULTICOPTER WITH BOOM-MOUNTED ROTORS
1. An aircraft, comprising:
- a fuselage;
a port side wing coupled to the fuselage;
a starboard side wing coupled to the fuselage;
wherein each of said wings has mounted thereto one or more booms, each boom having a forward end extending forward of a corresponding wing to which the boom is mounted and an after end extending aft of said corresponding wing to which the boom is mounted;
wherein a first subset of said booms each is mounted to said port side wing or said starboard side wing at a non-zero angle relative to a substantially vertical axis of the aircraft such that the boom is tilted inboard towards the fuselage; and
wherein a second subset of said booms each is mounted to said port side wing or said starboard side wing at a non-zero angle relative to the substantially vertical axis of the aircraft such that the boom is tilted outboard away from the fuselage.
A multicopter aircraft with boom-mounted rotors is disclosed. In various embodiments, a multicopter as disclosed herein includes a fuselage; a port side wing coupled to the fuselage; and a starboard side wing coupled to the fuselage. Each of the wings has mounted thereto one or more booms, each boom having a forward end extending forward of a corresponding wing to which the boom is mounted and an after end extending aft of said corresponding wing to which the boom is mounted. The aircraft further includes a first plurality of lift rotors, each rotor in said first plurality being mounted on a forward end of a corresponding one or said booms; and a second plurality of lift rotors, each rotor in said second plurality being mounted on an after end of a corresponding one or said booms. Each rotor produces vertical thrust independent of the thrust produced by the other rotors.
- 1. An aircraft, comprising:
a fuselage; a port side wing coupled to the fuselage; a starboard side wing coupled to the fuselage; wherein each of said wings has mounted thereto one or more booms, each boom having a forward end extending forward of a corresponding wing to which the boom is mounted and an after end extending aft of said corresponding wing to which the boom is mounted; wherein a first subset of said booms each is mounted to said port side wing or said starboard side wing at a non-zero angle relative to a substantially vertical axis of the aircraft such that the boom is tilted inboard towards the fuselage; and wherein a second subset of said booms each is mounted to said port side wing or said starboard side wing at a non-zero angle relative to the substantially vertical axis of the aircraft such that the boom is tilted outboard away from the fuselage.
- View Dependent Claims (2, 3, 4, 5, 6)
This application is a continuation of co-pending U.S. patent application Ser. No. 15/297,035, entitled MULTICOPTER WITH BOOM-MOUNTED ROTORS filed Oct. 18, 2016 which is incorporated herein by reference for all purposes.
Multicopter aircraft typically include a plurality of horizontally oriented rotors, sometimes referred to as “lift fans,” to provide lift, stability, and control. A flight control system, sometimes referred to as a “flight controller” or “flight computer”, may be provided to translate pilot or other operator input, and/or corrections computed by an onboard computer, e.g., based on sensor data, into forces and moments and/or to further translate such forces and moments into a set of actuator (e.g., lift rotors; propellers; control surfaces, such as ailerons; etc.) and/or associated parameters (e.g., lift fan power, speed, or torque) to provide the required forces and moments.
For example, pilot or other operator inputs may indicate a desired change in the aircraft'"'"'s speed, direction, and/or orientation, and/or wind or other forces may act on the aircraft, requiring the lift fans and/or other actuators to be used to maintain a desired aircraft attitude (roll/pitch/yaw), speed, and/or altitude.
An aircraft typically is considered to have six degrees of freedom of movement, including forces in the forward/back, side/side, and up/down directions (e.g., Fx, Fy, and Fz) and moments about the longitudinal (roll) axis, the transverse (pitch) axis, and the vertical (yaw) axis (e.g., Mx, My, and Mz). If an aircraft has more actuators than degrees of freedom, it must be determined how the various actuators will be used to act on the aircraft in response to commands received via manual and/or automated controls. For a given set of one or more pilot commands under given circumstances, some combinations of actuators capable of acting on the aircraft to achieve the result indicated by the pilot command(s) may be more effective and/or efficient than others. For example, some may consume more or less power and/or fuel than others, provide a more smooth transition from a current state than others, etc.
Rotors may spin at a high rate and could pose a risk to an occupant of a manned multicopter and/or to equipment housed in a fuselage or other structure comprising the multicopter.
Various embodiments of the invention are disclosed in the following detailed description and the accompanying drawings.
The invention can be implemented in numerous ways, including as a process; an apparatus; a system; a composition of matter; a computer program product embodied on a computer readable storage medium; and/or a processor, such as a processor configured to execute instructions stored on and/or provided by a memory coupled to the processor. In this specification, these implementations, or any other form that the invention may take, may be referred to as techniques. In general, the order of the steps of disclosed processes may be altered within the scope of the invention. Unless stated otherwise, a component such as a processor or a memory described as being configured to perform a task may be implemented as a general component that is temporarily configured to perform the task at a given time or a specific component that is manufactured to perform the task. As used herein, the term ‘processor’ refers to one or more devices, circuits, and/or processing cores configured to process data, such as computer program instructions.
A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.
A multicopter aircraft with angled rotors is disclosed. In various embodiments, a multicopter aircraft as disclosed herein includes a plurality of lift fans or other rotors disposed in a configuration around a fuselage and/or other centrally-located structure of the aircraft. In some embodiments, a first subset of the rotors may be disposed on a one side of the aircraft and a second subset of the rotors may be disposed on an opposite side of the aircraft. In various embodiments, each of at least a subset of the rotors is mounted at a corresponding non-zero angle off of a horizontal plane of the aircraft. In some embodiments, the angle at which each rotor is mounted is determined at least in part by a location of the rotor relative to the fuselage and/or a human or other occupied portion thereof, the angle being determined at least in part to ensure that a plane in which the rotor primarily rotates does not intersect the fuselage and/or a human or other occupied portion thereof. In various embodiments, the respective angles at which at least a subset of the rotors are mounted may be determined at least in part to provide the ability to generate lateral force components in the horizontal plane of the aircraft at rotor mount locations that are offset in the horizontal plane from a center of gravity of the aircraft, so as to provide an ability to use the rotors to control yaw of the aircraft (i.e., rotation about a vertical axis of the aircraft) by applying moments about the vertical axis.
Referring further to
In the example shown, sensors 116 provide sensor data 118 to online optimizer/mixer 110. Examples of sensors 116 and/or sensor data 118 may include one or more of airspeed, temperature, or other environmental conditions; actuator availability, failure, and/or health information; aircraft attitude, altitude, and/or other position information; presence/absence of other aircraft, debris, or other obstacles in the vicinity of the aircraft; actuator position information; etc. In various embodiments, online optimizer/mixer 110 may be configured to take sensor data 118 into account in determining an optimal mix of actuators and associated parameters to achieve a requested set of forces and moments. For example, in some embodiments, six or more lift fans may be provided to lift an aircraft into the air, enable the aircraft to hover, control aircraft attitude relative to the horizontal, etc. In some embodiments, failure of a lift fan may be reflected in sensor data 118, resulting in a seamless response by online optimizer/mixer 110, which provides an optimal set of actuators and parameters 112 that omits (does not rely on) the failed lift fan. Likewise, in some embodiments, sensor data reflecting diminished power/performance, overheating, etc., may be taken into consideration, such as by adjusting a mapping of actuator parameter to expected effect on the aircraft for affected actuators.
In various embodiments, each boom 206 is positioned at an angle relative to a vertical axis of the aircraft such that the lift fans 208 are mounted thereon at an associated angle, as described more fully in connection with
In the example shown in
In the example shown, four ailerons 214 are included, e.g., to provide redundancy. In some embodiments, if a single aileron 214 is lost or fails the remaining three ailerons 214 are sufficient to control the aircraft. Likewise, in some embodiments, loss of one rudder 218 results in one remaining rudder to provide a degree of yaw control, along with the lift fans. Finally, in some embodiments four elevators 216 are provided for loss/failure tolerance.
In some embodiments, an aircraft 200 as shown in
In various embodiments, the respective angles at which lift fans 208 may be oriented may be determined based at least in part on safety considerations, such as to increase the likelihood that debris thrown centrifugally from a lift fan, e.g., should the lift fan break apart, would be propelled on a trajectory and/or in a plane that does not intersect a human-occupied portion of fuselage 202. In some embodiments, two side by side seats are provided for passengers in a forward part of fuselage 202. Batteries to power the lift fans 208 and/or push propeller 210 may be located in a central/over wing part of the fuselage 202, and in some embodiments both the human-occupied and battery occupied parts of the fuselage are protected at least in part by canting the booms/lift fans as disclosed herein.
In some embodiments, lift fan cant angles may be determined at least in part via a constrained optimization design process. The fan cants (e.g., roll and pitch fan angles) may be determined by an optimization process in which an object is to minimize the amount of torque required by any individual motor for a variety of trimmed or equilibrium conditions including: angular accelerations, any individual fan failure, crosswinds, and center of gravity variations. In some embodiments, the optimization is subject to constraints of preventing the plane of the fan blade from intersecting the crew in the event of catastrophic failure of a fan. Another example of a constraint that may be applied is ensuring that the fans are aligned to the local flow angle for forward flight with the fans stopped and aligned with the boom.
In various embodiments, the effective forces and moments capable of being provided by each respective lift fan may be stored onboard the aircraft 200 in a memory or other data storage device associated with the onboard flight control system. In various embodiments, a matrix, table, database, or other data structure may be used.
In some embodiments, effectiveness under different operating conditions may be stored. For example, effectiveness of a lift fan or control surface may be different depending on conditions such as airspeed, temperature, etc. In some embodiments, forces and moments expected to be generated by a lift fan or other actuator under given conditions may be discounted or otherwise reduced, e.g., by a factor determined based at least in part on an environmental or other variable, such as a measure of lift fan motor health.
In an aircraft having angled lift fans as in the example shown in
Similarly, in the example shown the middle lift fan and the inboard lift fan have been angled in towards the fuselage 202, resulting in their respective planes of rotation being rotated downward by corresponding angles, such that they do not intersect the fuselage 202.
In various embodiments, angling lift fans or other rotors towards or away from a fuselage or critical portion thereof, and/or other critical structures, may decrease the risk that debris thrown centrifugally from the rotor would hit the fuselage or other structure.
Similar to the rear lift fans, the forward lift fans (associated with lateral force components Fy7-Fy12, in this example) would contribute moment components proportional to the x-axis distance x2 at which they are mounted relative to the center of gravity 220.
In various embodiments, the respective lift fans 208 may be rotated in alternating clockwise or counterclockwise rotations, e.g., to balance side forces associated with rotation direction. In the example shown in
In some embodiments, the wing 204 may not sweep upward to the same extent as shown in
In various embodiments, a flight control system, such as flight control system 100 of
In various embodiments, techniques disclosed herein may be used to provide a multicopter aircraft having angled lift fans and/or rotors. Each rotor may be mounted at an angle such that debris thrown centrifugally from the lift fan, in a plane of rotation of the lift fan, would not intersect the fuselage or other critical structure of the aircraft. In various embodiments, angling rotors as disclosed herein may provide a degree of authority over (ability to control or influence) yaw of the aircraft, e.g., during hover or vertical takeoff (lift) or landing operations.
Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention. The disclosed embodiments are illustrative and not restrictive.