Force application device for a control stick, control stick, method, program and aircraft

A force application device for an aircraft control stick, the force application device comprising:

• a mechanical joint configured to receive an aircraft control stick lever, the mechanical joint being rotationally movable about at least one axis from among a roll axis and a pitch axis,
• at least one force motor comprising at least one motor shaft extending along at least one direction of actuation, a rotation of the at least one motor shaft about the at least one direction of actuation being linked to a rotation of the mechanical joint about the at least one axis, the at least one force motor being configured to exert a resistive torque on the at least one motor shaft,
• at least one rheological brake configured to apply a resistive force to the at least one motor shaft,
• at least one sensor that measures at least one angular position and at least one sign of a velocity about the at least one axis and/or about the at least one motor shaft, and
• a calculator that controls the at least one rheological brake and the at least one force motor,
• wherein the calculator is configured to control the at least one rheological brake and the at least one force motor as a function of the at least one angular position and of the at least one sign of the velocity having been measured by the at least one sensor, to:
• when the at least one angular position corresponds to an angle of the aircraft control stick lever with respect to a prescribed neutral position, less than or equal in absolute value to a prescribed virtual stop threshold, control the at least one force motor to apply to the aircraft control stick lever a first resistive force as a function of the angle of the aircraft control stick lever and deactivate the at least one rheological brake, the first resistive force having a first determined value, which is non-zero at the prescribed virtual stop threshold,
• when the at least one angular position corresponds to an angle of the aircraft control stick lever with respect to the prescribed neutral position, which increases in absolute value beyond the prescribed virtual stop threshold, control the at least one force motor and activate the at least one rheological brake to apply to the aircraft control stick lever a second resistive force greater than the first value, and
• when the at least one angular position corresponds to an angle of the aircraft control stick lever with respect to the prescribed neutral position, which in absolute value decreases and is greater than the prescribed virtual stop threshold, control the at least one force motor to apply to the aircraft control stick lever a third return force as a function of the angle of the aircraft control stick lever and deactivate the at least one rheological brake.