Method of assisted piloting of a rotary wing aircraft having at least one propulsion propeller, an assisted piloting device, and an aircraft

A method of assisted piloting for an aircraft having a rotary wing and a propulsion unit including at least one propulsion propeller, each propeller having a plurality of first blades, and the rotary wing including a rotor provided with a plurality of second blades, the method comprising:

• translating an order to an aircraft controller given by a pilot of the aircraft to request a movement in a direction into an acceleration setpoint along said direction;
• transforming, by a processor in communication with the aircraft controller, the acceleration setpoint by predetermined relationships into a required longitudinal attitude setpoint (θ*) and into a first required load factor setpoint (Nx*) in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft;
• transmitting the required longitudinal attitude setpoint (θ*) to a first automatic system for maintaining longitudinal attitude by controlling a longitudinal cyclic pitch of the second blades of the rotary wing in order to comply with said required longitudinal attitude setpoint (θ*);
• and
• transmitting the first required load factor setpoint (Nx*) to a second automatic system for maintaining load factor by controlling a collective pitch of the first blades of the propulsion unit in order to comply with said first load factor setpoint (Nx*);
• wherein when said order is an order to move in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft, said order to move in a longitudinal direction is translated into a longitudinal acceleration setpoint, and then the longitudinal acceleration setpoint is transformed by predetermined relationships solely into the required longitudinal attitude setpoint (θ*) transmitted to the first automatic system for maintaining longitudinal attitude and into the first required load factor setpoint (Nx*) transmitted to the second automatic system for maintaining load factor;
• wherein said required longitudinal attitude setpoint (θ*) is determined by the following first longitudinal control relationship:
• θ*=(180/Pi)×[(−a)×(γx*/g)−k]/(a+b)
• where “θ*” represents the required longitudinal attitude setpoint expressed in degrees, “Pi” represents the number π, “γx*” represents the longitudinal acceleration setpoint, “g” represents the acceleration due to gravity, “×” represents the multiplication sign, “/” represents the division sign, “a” represents a first longitudinal constant, “b” represents a second longitudinal constant, and “k” represents a third longitudinal constant.

A method of assisted piloting for an aircraft having a rotary wing and a propulsion unit including at least one propulsion propeller, each propeller having a plurality of first blades, and the rotary wing including a rotor provided with a plurality of second blades, the method comprising:

• translating an order given to an aircraft controller by a pilot of the aircraft to request a movement in a direction into an acceleration setpoint along said direction;
• transforming, by a processor in communication with the aircraft controller, the acceleration setpoint by predetermined relationships into a required longitudinal attitude setpoint (θ*) and into a first required load factor setpoint (Nx*) in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft;
• transmitting the required longitudinal attitude setpoint (θ*) to a first automatic system for maintaining longitudinal attitude by controlling a longitudinal cyclic pitch of the second blades of the rotary wing in order to comply with said required longitudinal attitude setpoint (θ*);
• and
• transmitting the first required load factor setpoint (Nx*) to a second automatic system for maintaining load factor by controlling a collective pitch of the first blades of the propulsion unit in order to comply with said load factor setpoint (Nx*);
• wherein when said order is an order to move in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft, said order to move in a longitudinal direction is translated into a longitudinal acceleration setpoint, and then the longitudinal acceleration setpoint is transformed by predetermined relationships solely into the required longitudinal attitude setpoint (θ*) transmitted to the first automatic system for maintaining longitudinal attitude and into the first required load factor setpoint (Nx*) transmitted to the second automatic system for maintaining load factor;
• wherein said first required load factor setpoint (Nx*) is determined by the following second longitudinal control relationship:
• Nx*=[b×(γx*/g)−k]/(a+b)
• where “Nx*” represents said first required load factor setpoint, “γx*” represents the longitudinal acceleration setpoint, “g” represents the acceleration due to gravity, “×” represents the multiplication sign, “/” represents the division sign, “a” represents a first longitudinal constant, “b” represents a second longitudinal constant, and “k” represents a third longitudinal constant.

A method of assisted piloting for an aircraft having a rotary wing and a propulsion unit including at least one propulsion propeller, each propeller having a plurality of first blades, and the rotary wing including a rotor provided with a plurality of second blades, the method comprising:

• translating an order given to an aircraft controller by a pilot of the aircraft to request a movement in a direction into an acceleration setpoint along said direction;
• transforming, by a processor in communication with the aircraft controller, the acceleration setpoint by predetermined relationships into a required longitudinal attitude setpoint (θ*) and into a first required load factor setpoint (Nx*) in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft;
• transmitting the required longitudinal attitude setpoint (θ*) to a first automatic system for maintaining longitudinal attitude by controlling a longitudinal cyclic pitch of the second blades of the rotary wing in order to comply with said required longitudinal attitude setpoint (θ*);
• and
• transmitting the first required load factor setpoint (Nx*) to a second automatic system for maintaining load factor by controlling a collective pitch of the first blades of the propulsion unit in order to comply with said first load factor setpoint (Nx*);
• wherein, when said order (O) is an order to move in a vertical direction parallel to the gravity direction, this movement order is translated along an elevation direction into a vertical acceleration setpoint, and then this vertical acceleration setpoint is transformed into the required longitudinal attitude setpoint (θ*) that is transmitted to the first automatic system for maintaining longitudinal attitude, into the first load factor setpoint (Nx*) that is transmitted to the second automatic system for maintaining load factor, and into a second load factor setpoint (NZcoll*) that is transmitted to a third automatic system for maintaining load factor by controlling collective pitch variation of the second blades of the rotary wing;
• wherein said required longitudinal attitude setpoint is determined by the following first vertical control relationship:
• θ*=∫q*dt
• with:
• q*=(g/u)×[−a″×(Nz*+cos θ×cos φ)−k″]/(a″+b″)
• and:
• Nz*=(1/(a′×cos θ×cos φ+b′×sin θ))×(−a′×(Γz*/g+1)−k′×sin θ)
• where “θ*” represents the required longitudinal attitude setpoint expressed in radians, “Γz*” represents the vertical acceleration setpoint, “g” represents the acceleration due to gravity, “u” represents the current longitudinal speed of the aircraft, “θ” represents the current longitudinal attitude, “φ” represents the current roll angle of the aircraft, “×” represents the multiplication sign, “/” represents the division sign, “a′” represents a first vertical constant, “b′” represents a second vertical constant, “k′” represents a third vertical constant, “a″” represents a fourth vertical constant, “b″” represents a fifth vertical constant, and “k″” represents a sixth vertical constant, the required longitudinal attitude setpoint θ* being frozen when the vertical acceleration setpoint is equal to 1.

A method of assisted piloting for an aircraft having a rotary wing and a propulsion unit including at least one propulsion propeller, each propeller having a plurality of first blades, and the rotary wing including a rotor provided with a plurality of second blades, the method comprising:

• translating an order given to an aircraft controller by a pilot of the aircraft to request a movement in a direction into an acceleration setpoint along said direction;
• transforming, by a processor in communication with the aircraft controller, the acceleration setpoint by predetermined relationships into a required longitudinal attitude setpoint (θ*) and into a first required load factor setpoint (Nx*) in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft;
• transmitting the required longitudinal attitude setpoint (θ*) to a first automatic system for maintaining longitudinal attitude by controlling a longitudinal cyclic pitch of the second blades of the rotary wing in order to comply with said required longitudinal attitude setpoint (θ*);
• and
• transmitting the first required load factor setpoint (Nx*) to a second automatic system for maintaining load factor by controlling a collective pitch of the first blades of the propulsion unit in order to comply with said first load factor setpoint (Nx*);
• wherein, when said order (O) is an order to move in a vertical direction parallel to the gravity direction, this movement order is translated along an elevation direction into a vertical acceleration setpoint, and then this vertical acceleration setpoint is transformed into the required longitudinal attitude setpoint (θ*) that is transmitted to the first automatic system for maintaining longitudinal attitude, into the first load factor setpoint (Nx*) that is transmitted to the second automatic system for maintaining load factor, and into a second load factor setpoint (NZcoll*) that is transmitted to a third automatic system for maintaining load factor by controlling collective pitch variation of the second blades of the rotary wing;
• wherein said first load factor setpoint (Nx*) is determined by the following second vertical control relationship:
• Nx*=(1/(a′×cos θ×cos φ+b′×sin θ))×(b′×(Γz*/g+1)−k′×cos θ×cos φ)
• where “Nx*” represents the first required load factor setpoint, “Γz*” represents the vertical acceleration setpoint, “g” represents the acceleration due to gravity, “×” represents the multiplication sign, “/” represents the division sign, “θ” represents the current longitudinal attitude, “φ” represents the current roll angle of the aircraft, “a′” represents a first vertical constant, “b′” represents a second vertical constant, “k′” represents a third vertical constant, in the absence of said order to move in a vertical direction, said first setpoint Nx* being equal to the sine of the current longitudinal attitude (θ).

A method of assisted piloting for an aircraft having a rotary wing and a propulsion unit including at least one propulsion propeller, each propeller having a plurality of first blades, and the rotary wing including a rotor provided with a plurality of second blades, the method comprising:

• translating an order given to an aircraft controller by a pilot of the aircraft to request a movement in a direction into an acceleration setpoint along said direction;
• transforming, by a processor in communication with the aircraft controller, the acceleration setpoint by predetermined relationships into a required longitudinal attitude setpoint (θ*) and into a first required load factor setpoint (Nx*) in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft;
• transmitting the required longitudinal attitude setpoint (θ*) to a first automatic system for maintaining longitudinal attitude by controlling a longitudinal cyclic pitch of the second blades of the rotary wing in order to comply with said required longitudinal attitude setpoint (θ*);
• and
• transmitting the first required load factor setpoint (Nx*) to a second automatic system for maintaining load factor by controlling a collective pitch of the first blades of the propulsion unit in order to comply with said first load factor setpoint (Nx*);
• wherein, when said order (O) is an order to move in a vertical direction parallel to the gravity direction, this movement order is translated along an elevation direction into a vertical acceleration setpoint, and then this vertical acceleration setpoint is transformed into the required longitudinal attitude setpoint (θ*) that is transmitted to the first automatic system for maintaining longitudinal attitude, into the first load factor setpoint (Nx*) that is transmitted to the second automatic system for maintaining load factor, and into a second load factor setpoint (NZcoll*) that is transmitted to a third automatic system for maintaining load factor by controlling collective pitch variation of the second blades of the rotary wing;
• wherein said second load factor setpoint (NZcoll*) is determined by the following third vertical control relationship:
• NZcoll*=(b″×(Nz*+cos θ×cos φ)−k″)/(a″+b″) and
• Nz*=1/(a′×cos θ×cos φ+b′×sin θ))×(−a′×(Γz*/g+1)−k′×sin θ)
• where “NZcoll” represents the second required load factor setpoint, “Γz*” represents the vertical acceleration setpoint, “g” represents the acceleration due to gravity, “θ” represents the current longitudinal attitude, “φ” represents the current roll angle of the aircraft, “×” represents the multiplication sign, “/” represents the division sign, “a′” represents a first vertical constant, “b′” represents a second vertical constant, “k′” represents a third vertical constant, “a″” represents a fourth vertical constant, “b″” represents a fifth vertical constant, and “k″” represents a sixth vertical constant.

A device for assisted piloting of an aircraft having a rotary wing and a propulsion unit having at least one propulsion propeller, each propeller having a plurality of first blades and the rotary wing having a rotor having a plurality of second blades, the device comprising:

• control means suitable for being controlled by a pilot to deliver a movement order for movement in a direction;
• a processor unit connected to the control means, the processor unit executing instructions to transform said order into an acceleration setpoint in said direction, and then to transform said acceleration setpoint, by predetermined relationships, into a required longitudinal attitude setpoint (θ*) and into a first required load factor setpoint (Nx*) in a longitudinal direction of the aircraft parallel to a roll axis of said aircraft;
• a first automatic system for maintaining longitudinal attitude by controlling a longitudinal cyclic pitch of the second blades of the rotary wing in order to comply with the required longitudinal attitude setpoint (θ*);
• and
• a second automatic system for maintaining load factor by controlling a collective pitch of the first blades of the propulsion unit in order to comply with said first load factor setpoint (Nx*).