Rotorcraft autopilot and methods

• US 10,351,231 B2
• Filed: 08/26/2017
• Issued: 07/16/2019
• Est. Priority Date: 02/10/2012
• Status: Active Grant

• Current Assignee: Merlin Technologies Incorporated
• Original Assignee: Merlin Technologies Incorporated
• Inventors: Mercer, John E., Albion, Nicholas, Bartel, Mark, Feifel, Marc, Marvin, Mark
• Primary Examiner(s): Marc-Coleman, Marthe Y
• Application Number:
  US15/687,454
• Publication Number:
  US 20180093763A1
• Time in Patent Office: 689 Days
• Field of Search: 701 3
• CPC Class Codes: B64C 13/0421 control sticks for primary flight controls
• CPC Class Codes: B64C 13/044 operated by feet, e.g. pedals
• CPC Class Codes: B64C 13/18 using automatic pilot
• CPC Class Codes: B64C 13/341 having duplication or stand-by provisions
• CPC Class Codes: B64C 27/56 characterised by the control initiating means, e.g. manually actuated
• CPC Class Codes: B64C 27/57 automatic or condition responsive, e.g. responsive to rotor speed, torque or thrust
• CPC Class Codes: B64C 27/58 Transmitting means, e.g. interrelated with initiating means or means acting on blades means acting on blades B64C27/72
• CPC Class Codes: B64C 27/59 mechanical
• CPC Class Codes: B64C 27/64 using fluid pressure, e.g. having fluid power amplification
• CPC Class Codes: B64C 27/68 using electrical energy, e.g. having electrical power amplification
• CPC Class Codes: G05D 1/0077 using redundant signals or controls
• CPC Class Codes: G05D 1/0816 to ensure stability
• CPC Class Codes: G05D 1/0858 specially adapted for vertical take-off of aircraft
• CPC Class Codes: G05D 1/102 specially adapted for vertical take-off of aircraft
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

A helicopter autopilot system includes an inner loop for attitude hold for the flight of the helicopter including a given level of redundancy applied to the inner loop. An outer loop is configured for providing a navigation function with respect to the flight of the helicopter including a different level of redundancy than the inner loop. An actuator provides a braking force on a linkage that serves to stabilize the flight of the helicopter during a power failure. The actuator is electromechanical and receives electrical drive signals to provide automatic flight control of the helicopter without requiring a hydraulic assistance system in the helicopter. The autopilot can operate the helicopter in a failed mode of the hydraulic assistance system. A number of flight modes are described with associated sensor inputs including rate based and true attitude modes.

Claims

1. A flight control system for selective automatic control of the forward flight of a helicopter which forward flight is characterized by a set of orientation parameters including a pitch orientation, a roll orientation and a yaw orientation, said system comprising:

a triaxial MEMS rate sensor supported by said helicopter for generating a roll rate signal, a pitch rate signal and a yaw rate signal that are responsive to changes in said roll orientation, pitch orientation and yaw orientation, respectively;

a MEMS triaxial accelerometer for generating accelerometer signals responsive to said forward flight;

a GPS receiver supported by said helicopter for generating a course signal, an altitude signal and a speed signal responsive to the forward flight of the helicopter;

a triaxial magnetometer to generate magnetometer signals;

a controller supported by said helicopter to receive a set of inputs including the pitch rate signal, the roll rate signal, the yaw rate signal, the accelerometer signals, the course signal, the magnetometer signals, the speed signal and the altitude signal to determine a true attitude of the helicopter and generate a set of control signals to maintain a stable forward flight orientation of the helicopter according to a selected course defined on the ground and a selected altitude; and

an actuator arrangement that receives the set of control signals to adjust the forward flight of the helicopter based on the set of control signals.

2. The system of claim 1 wherein said GPS receiver includes no more than one GPS antenna.

3. A flight control system for selective automatic control of the forward flight of a helicopter which forward flight is characterized by a set of orientation parameters including a pitch orientation, a roll orientation and a yaw orientation, said system comprising:

a triaxial MEMS rate sensor supported by said helicopter for generating a roll rate signal, a pitch rate signal and a yaw rate signal that are responsive to changes in said roll orientation, pitch orientation and yaw orientation, respectively;

a MEMS triaxial accelerometer for generating accelerometer signals responsive to said forward flight;

a GPS receiver supported by said helicopter for generating a course signal and a speed signal responsive to the forward flight of the helicopter;

a triaxial magnetometer to generate magnetometer signals;

a controller supported by said helicopter to receive a set of inputs including the pitch rate signal, the roll rate signal, the yaw rate signal, the acceleration signals, the course signal and the speed signal to determine a true attitude of the helicopter and to generate a set of control signals to maintain a stable forward flight orientation of the helicopter according to a selected course defined on the ground and a selected speed on the selected course; and

an actuator arrangement for receiving the set of control signals to adjust the forward flight of the helicopter based on the set of control signals.

4. A flight control system for selective automatic control of the flight of a helicopter that is capable of flying in a hover, which hover is characterized by a set of orientation parameters including a pitch orientation, a roll orientation, a yaw orientation and a position above the ground, said system comprising:

a MEMS sensor arrangement supported by said helicopter for generating a pitch rate signal that is responsive to changes in said pitch orientation and a roll rate signal that is responsive to changes in said roll orientation, a yaw rate signal that is responsive to said yaw orientation and acceleration signals responsive to said hover;

a MEMS triaxial accelerometer for generating accelerometer signals responsive to said forward flight;

a magnetometer for generating a magnetic heading signal;

a GPS receiver supported by said helicopter for generating a position signal, a course signal, and a speed signal responsive to the hover of the helicopter;

a processing arrangement supported by said helicopter for receiving a set of inputs including the pitch rate signal, the roll rate signal, the yaw rate signal, the acceleration signals, the position signal, the course signal, the speed signal, and the magnetic heading signal to determine a true attitude of the helicopter and to generate a set of control signals to maintain a stable hover of the helicopter according to a selected hovering position; and

an actuator arrangement for receiving the set of control signals to adjust the hover of the helicopter based on the set of control signals.