OSCILLATION SYSTEM

Description

BACKGROUND

[0001] There is sometimes a requirement to provide oscillation to a user-input device such as a control yoke or inceptor for an aircraft. The oscillation may be provided using an oscillation device. The oscillation of the user-input device may be triggered in response to an input from at least one sensor or warning system. The oscillation device, often known as a stick shaker, may be used as a backup or alternative to auditory or visual alerts and notify the user of the existence of the sensor input or provide a warning, potentially avoiding an accident.

[0002] Stick shakers commonly comprise an unbalanced flywheel mounted to a user-input device, the flywheel connected to a motor. The stick shaker may be used to warn a pilot of an impending stall of an aircraft. The stick shaker may induce shaking of the user-input device mimicking the frequency and amplitude of the stick shaking that can occur due to airflow separation in low-speed aircraft as they approach the stall.

[0003] US 6 000 662 A (TODESCHI MICHEL [FR] ET AL) 14 December 1999, discloses a flying aid device for a fly-by-wire aircraft which has at least two mechanically independent control columns.

[0004] GB 2 482 407 A (WOODWARD MPC INC [US]) 1 February 2012, discloses a position control system for cross coupled operation of fly-by-wire control columns.

[0005] EP 2 826 707 A1 (MCCULLOCH NORMAN L [GB]) 21 January 2015, discloses a feedback system for the flying control member in the cockpit of an aircraft having servo mechanism for adjusting the flying control surfaces in accordance with movement by a pilot of the flying control member.

[0006] US 2015 / 344128 A1 (SANDRI FLORENCE [FR]) 3 December 2015, discloses a device for warning a rotorcraft pilot by means of tactile signals and making use of a trim actuator connected to a flight control member.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 illustrates a cueing apparatus for incorporation into an aircraft control system. Figure 2 illustrates a modified cueing apparatus for incorporation into an aircraft control system, the modified active cueing apparatus comprising an oscillation system. DETAILED DESCRIPTION

[0008] Figure 1 illustrates an active cueing apparatus 100 for incorporation into an aircraft control system, the active cueing apparatus 100 comprising a user-input device 110, and a resistive force system 120. The cueing apparatus 100 is similar to the apparatus as described in US 20160004270 A1 "Inceptor Apparatus".

[0009] Active cueing apparatus 100 provides force feedback to the user-input device 110 in a predetermined relationship via the use of at least one set of motors. For simplicity the motors and other mechanisms of the cueing apparatus are not shown. The cueing apparatus 100 is able to pivot about axis 130 and axis 140, although it may also be able to pivot or rotate about other axes not shown in Figure 1.

[0010] The feedback is provided by a resistive force circuitry 120 in a manner similar to that disclosed in published application US 20160004270 A1. The resistive force circuitry 120 comprises at least one motor of a first set of motors. The resistive force circuitry 120 provides a resistive force to the user-input device 110 using the at least one motor of the first set of motors. The resistive force circuitry 120 may comprise a plurality of sets of motors, and each axis may have associated with it a particular set of motors. A set of motors may be associated with one of the axis 130 and / or 140, such that the feedback is provided substantially to axis 130 and / or axis 140.

[0011] When the cueing apparatus 100 and / or resistive force circuitry 120 is operable to provide such a resistive force feedback the cueing apparatus 100 and / or resistive force circuitry 120 may be deemed to be in an active mode. If the cueing apparatus 100 and / or resistive force circuitry 120 is not operable to provide such a resistive force, the cueing apparatus 100 and / or resistive force circuitry 120 may be deemed to be in a passive mode or an inactive mode.

[0012] At least due to the possibility of system or electrical failures, or merely user preference, there may be a requirement for a cueing apparatus 100 similar to the type described in US 20160004270 A1 to comprise an oscillation system capable of oscillating the user-input device even when the cueing apparatus 100 and / or resistive force circuitry 120 is in a passive or inactive mode. A possible solution would be to include a known style of stick shaker, such as an unbalanced flywheel, into the user-input device 110 along with separate circuitry to power the motor. However the space in the user-input device 110 may be limited and adding extra motors may increase the complexity and cost of the device. Extra motors may also increase the mass of the user-input device 110 or the cueing apparatus 100 as a whole, increasing the inertia of the user-input device 110 which may negatively affect performance.

[0013] Figure 2 illustrates a modified cueing apparatus 200 comprising an oscillation system 210, resistive force circuitry 120 and user-input device 110. Reference numerals for similar features are shared with Figure 1. The resistive force may be provided by the at least one motor of the at least one set of motors of the resistive force circuitry 120. The resistive force circuitry 120 of the modified cueing apparatus 200 may be substantially similar to the circuitry as described in US 20160004270 A1, and is configured to provide a resistive force in at least one of axis 130 and / or axis 140.

[0014] The oscillation system 210 allows for the user-input device 110 to be oscillated in response to an input from at least one sensor irrespective of the status of the resistive force circuitry 120, e.g. the oscillation system 210 allows for an oscillation to be applied to the user-input device 110 even when the resistive force circuitry 120 and / or the modified cueing apparatus 120 is operating in a passive mode or an inactive mode. The oscillation system 210 also allows for a stick shaker to be used in an active inceptor without the use of a offset cam or unbalanced flywheel.

[0015] The oscillation system 210 comprises oscillation circuitry configured to cause at least one motor of the first set of motors to provide an oscillation to a user-input device 110 in at least one axis of the user-input device 110. The at least one motor of the first set of motors is shared with the resistive force circuitry 120, such that the resistive force circuitry 120 and the oscillation system 210 provide a current to the same electrical windings. The oscillation is triggered in response to an input from at least one sensor or warning system.

[0016] Due to the requirements of the oscillation circuitry, the oscillation circuitry may be significantly less complex than the resistive force circuitry 120. The oscillation circuitry is used merely to provide an oscillation to the user-input device 110 in response to an input from at least one sensor or warning system. Therefore significantly less processing power may be required for the oscillation circuitry compared to the resistive force circuitry 120. This may allow the oscillation circuitry to be conveniently installed in a cueing apparatus without increasing the inertia of the user-input device 110. Furthermore the amplitude and frequency of the oscillation may be independent from any user input to the user-input device 110 and / or the position of the user-input device 110 relative to the aircraft. This is in contrast to the resistive force circuity where the feedback force may be directly related to the user input to the user-input device 110 and / or the position of the user-input device 110 relative to the aircraft.

[0017] In the current invention, the oscillation circuitry is operable to provide an oscillation to the user-input device 110 when the modified cueing apparatus 200 is in a passive or inactive mode.

[0018] In the current invention, the input from the at least one sensor indicates that the risk of impeding stall of the aircraft is over a threshold value. In some examples the at least one sensor may comprise a stall warning system of an aircraft. A stall warning system may use signals received from various sensors associated with the aircraft to indicate when the risk of impending stall is above a predefined threshold. In some examples the oscillation provided to the user-input device 110 may mimic an oscillation of the user-input device 110 felt if the user-input device 110 was mechanically linked to the flight control systems and the aircraft was in a stall. Hence, in some examples the magnitude of the oscillation may be directly related to the magnitude of the risk of impending stall and / or the severity of the warning.

[0019] In some examples the oscillation is at a single frequency. In some examples the oscillation is provided at multiple frequencies. In some examples the one or more frequencies are selected from a range of 0.1 Hz to 50 Hz, or preferably from 10 Hz to 25 Hz, or most preferably from 15 to 20 Hz. The at least one motor may comprise a brushless DC motor, a limited angle torque motors, direct drives or voice coil actuators however it is not limited to the aforementioned types of motors, and any suitable type of motor may be used.

[0020] In some examples the modified cueing apparatus 200 may also comprise a second resistive force circuitry to provide a resistive force to the user-input device 110 in a pre-determined relationship. The second resistive force circuitry is operable to use at least one motor of a second set of motors, and the second set of motors are separate to the first set of motors. The oscillation system 210 is configured to provide an oscillation using at least one motor of the first set of motors and / or the at least one motor of the second set of motors. The first resistive force circuitry 120 is to provide the resistive force substantially in a first axis 130 of the user-input device 110, and the second resistive force circuitry is to provide the resistive force substantially in a second axis 140 of the user-input device 110, the first axis 130 and the second axis 140 substantially orthogonal to each other. The first and second resistive force circuitry may share control units, or may have separate control units.

[0021] In some examples the oscillation is configured to be provided to at least one of a roll axis, pitch axis, and yaw axis of the user-input device 110. It is believed that a user is not able to distinguish, for example, a pitch axis stall warning being given by an oscillation in the roll axis of the user-input device 110. This may be advantageous as it at least doubles the probability of the availability of the stick shaker as the stick may be shaken by either the roll, pitch or yaw axis of the user-input device 110. This means that there is further redundancy compared to a conventional stick shaker as the oscillation may be available if at least one of the electrical windings in each axis is available, whereas in traditional stick shakers if the electrical windings or motor driving the unbalanced flywheel are not available then the conventional stick shaker would not function.

[0022] In some examples the oscillation circuitry may comprise machine readable storage media and processing means, the machine readable media containing instructions, that when executed cause the processing means to cause the at least one motor of the first set of motors to provide an oscillation of the user-input device in at least one axis of the user-input device, the oscillation triggered in response to an input from at least one sensor.

Claims

1. A cueing apparatus (200) for incorporation into an aircraft control system, the apparatus comprising: a user-input device (110) for operating the aircraft control system, and pivotable about a first axis (140); a resistive force circuitry (120); at least one motor of a first set of motors; the resistive force circuitry being configured to provide a resistive force substantially in the first axis (140) of the user-input device to the user-input device (110), using the at least one motor of the first set of motors, in a predetermined relationship; and wherein the cueing apparatus (200) further comprises: an oscillation system (210) comprising: oscillation circuitry configured to cause the at least one motor of a first set of motors to provide an oscillation of the user-input device (110) in the first axis (140) of the user-input device, the oscillation triggered in response to an input from at least one sensor, wherein the oscillation circuitry is configured to operate independently from the resistive force circuitry (120) such that the oscillation circuitry may provide an oscillation to the user-input device (110), using the at least one motor of the first set of motors, when the resistive force circuitry (120) is inactive and / or in a low-power state, and wherein the input from the at least one sensor is indicative of a risk of a stall of the aircraft being over a threshold value.

2. The cueing apparatus according to any preceding claim, wherein the at least one motor comprises at least one brushless DC motor.

3. The cueing apparatus according to any preceding claim, wherein the oscillation is provided at approximately 10-25 Hz.

4. The cueing apparatus according to any preceding claim, wherein the oscillation is configured to be provided to at least one of a roll axis, pitch axis, and yaw axis of the user-input device.

5. The cueing apparatus according to any preceding claim, wherein the cueing apparatus further comprises: at least one motor of a second set of motors; a second resistive force circuitry to provide a resistive force to the user-input device (110), using the at least one motor of the second set of motors, in a pre-determined relationship, the second set of motors separate to the first set of motors; and the oscillation system is configured to provide an oscillation using at least one motor of the first set of motors and / or the at least one motor of the second set of motors, wherein the second resistive force circuitry is to provide the resistive force substantially in a second axis (130) of the user-input device, the first axis and the second axis substantially orthogonal to each other.