Side lever grip with minimum cross axis control coupling

Abstract

The invention relates to a side lever grip with minimum cross axis control coupling. Specifically, a side lever grip is disclosed that minimizes intersecting axis control coupling about three or more control axes, where one of the control axes provides a directional (yaw) input by twisting the grip in a clockwise / counterclockwise direction. Minimizing cross axis control in accordance with the embodiments disclosed herein is achieved primarily by substantially coincidence of a grip reference point (GRP) of the side lever grip (i.e., a theoretical point at which pitch and roll forces are applied) with the yaw axis of rotation. By providing the GRP substantially coincident with the yaw rotation axis, unexpected yaw torque is minimized when control inputs are applied on the side levers on a pitch axis and a roll axis.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority of U.S. Provisional Application Serial No. 63 / 597,408, filed on November 9, 2023, and is based on and claims the benefit of priority of U.S. Application Serial No. 18 / 937,761, filed on November 5, 2024, the entire contents of each of which are expressly incorporated herein by reference. Technical Field

[0003] Embodiments disclosed herein relate generally to the field of aircraft flight control systems. In a particularly preferred form, embodiments herein relate to a sidestick grip capable of commanding control of an aircraft relative to multiple (eg, 3 or 4) axes. Background Art

[0004] Technological advances in recent years, particularly in batteries with high power density, have created a need for vertical take-off and landing (VTOL) aircraft to serve passengers in urban environments. In order to reduce the weight of such VTOL aircraft, it has been proposed to use more compact pilot-operated controls than those proposed by the prior art.

[0005] Conventional aircraft typically use a yoke or 2-axis sidestick with longitudinal and lateral movement to control the aircraft attitude about the pitch axis and the roll axis, respectively. Rudder pedals are typically used for directional (yaw) control about the yaw axis. However, rudder pedals are not often employed on modern fly-by-wire (FBW) aircraft systems compared to previous aircraft that employed mechanical linkages because FBW systems are able to automatically perform tasks that would normally require separate pedal control inputs, such as coordinated turns. Therefore, there are advantages to using a more compact construction of pilot-controlled controls on aircraft for the emerging urban air mobility (UAM) market. In this regard, it has been proposed that the rudder pedals may be replaced by a 3-axis sidestick grip, in which yaw is controlled by twisting the sidestick grip, while pitch and roll are controlled by forward / backward movement and inboard / outboard movement of the sidestick grip, respectively.

[0006] One of the challenges associated with sidesticks with more than three axes is how to minimize cross-axis control coupling (i.e., allowing input to one of the control axes without activating control input to any of the remaining control axes). Minimizing cross-axis control coupling requires that the control forces and displacement sensitivities of each control axis be compatible so that normal inputs to one control axis do not cause significant unintended inputs to the other axes. Conventional sidesticks use independent preload springs to avoid cross-axis coupling between pitch and roll. However, the shape of the grip of a conventional 2-axis sidestick is not suitable to avoid cross-axis coupling when control needs to be applied about the yaw axis. The points at which roll and pitch forces are applied, also known as grip reference points (GRPs), are typically located away from the yaw axis of rotation, creating moment arms that in turn cause significant unintended yaw movement when forces are applied to those axes.

[0007] According to currently known technology, the problem of cross-axis control coupling has been minimized by adding spring preload forces or interruption forces on the yaw movement axis. According to these prior art proposals, when the pilot wishes to issue a directional yaw command, a high torque must be applied to the side stick. However, this conventional proposal is also undesirable because it presents control difficulties when only a small directional input is required. Other side sticks proposed in the art use an almost vertical grip design, but this arrangement is also inadequate for aircraft ergonomics. For reference, MIL-STD-1797A recommends that the side stick neutral position or tilt angle should be within the range of 10° to 17° forward from the vertical and within the range of 8° to 12° inside from the vertical. Therefore, any solution to the previously mentioned cross-axis control problem must take into account these ergonomic requirements.

[0008] As an example of the difficulty in finding an optimal solution in the prior art, the following factual considerations need to be noted:

[0009] (a) According to Title 14 of the Federal Aviation Regulations (FAR) § 23.143 (Amendment 62), which limits the forces applied to the stick for a long period of time: the normal sidestick force for the pitch axis is approximately 10 lbf and the normal sidestick force for the roll axis is approximately 5 lbf.

[0010] (b) For a typical sidestick with a neutral position of 17° forward from vertical and a GRP 6" above the pitch / roll pivot point, the GRP will be almost 2" forward of the yaw rotation axis. Multiplying this distance by the typical roll force of 5 lbf will produce a coupled torque on the yaw axis of greater than 9 in-lbf.

[0011] (c) A similar calculation for a neutral position 10° inboard from vertical and a typical pitch force of 10 lbf produces a coupled torque in excess of 10 in-lbf about the yaw axis.

[0012] (d) To counteract this coupled torque, the yaw breakaway would need to be above these values, which is undesirable because if so the normal directional command would already be at the limit, causing pilot fatigue when twisting the grip.

[0013] Therefore, there is a need in the art for a sidestick grip for aircraft control inputs in more than 3 axes that is ergonomically designed and minimizes, if not completely eliminates, cross-axis control coupling. Embodiments disclosed herein are directed to providing such a solution. Summary of the invention

[0014] In summary, embodiments disclosed herein relate to a functional sidestick grip that minimizes cross-axis control coupling about three or more control axes, wherein one of the control axes provides a directional (yaw) input by twisting the grip. Minimized cross-axis control according to embodiments disclosed herein is achieved by substantially coinciding the grip reference point (GRP) (i.e., the theoretical application point of pitch and roll forces) with the yaw rotation axis. In embodiments disclosed herein, whereby the GRP is substantially coincident with the yaw rotation axis, unintended yaw torques are minimized when control inputs are applied to the sidestick in the pitch and roll axes.

[0015] According to some embodiments, a side stick grip that allows for aircraft control about at least three axes is provided, the side stick grip having a lower grip section adapted to be grasped by a pilot's hand and defining a side stick center axis. A base is coupled to a lower end of the lower grip section and adapted to be mounted to an aircraft structure to allow the lower grip section to move in a forward / aft direction and an inboard / outboard direction to allow for aircraft control about a pitch axis and a roll axis, respectively, and to allow the lower grip section to twist in a clockwise / counterclockwise direction about a yaw axis to allow for aircraft control about the yaw axis. Importantly, the lower grip section defines a grip reference point (GRP) that establishes a theoretical point at which forces are applied to the side stick controller about the pitch axis and the roll axis, wherein the yaw axis is substantially coincident with the GRP and the side stick center axis. The lower grip section may include a contoured recess that allows corresponding fingers of the pilot's hand to rest against the contoured recess when the lower grip section is grasped.

[0016] To improve ergonomics, the base mounts the sidebar grips to define a forward and medial inclination relative to a vertical transverse plane and a vertical longitudinal plane, respectively. According to some embodiments, the forward inclination may be at an angle α of 10°-17° relative to the vertical transverse plane, typically 12°-15°, such as 13°±1°, while the medial inclination may be at an angle β of 2°-10° relative to the vertical longitudinal plane, typically 4°-6°, such as about 5°±1°.

[0017] The throttle stick-shaped head section may be joined to the upper end of the lower grip section. The throttle stick-shaped head section may include a laterally oriented (relative to the centerline of the side stick grip) semi-cylindrical first head portion and a frusto-conical second head portion protruding outwardly in a medial direction from the cylindrical first head portion. According to some embodiments, the first head portion may include a recessed arcuate guide, and an arcuate segment of a thumb wheel operatively mounted to the recessed arcuate guide for thumb-activated arcuate sliding movement in the forward and rearward directions.

[0018] These and other aspects and advantages of the present invention will become more apparent after careful consideration of the detailed description of the preferred exemplary embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Combined by reference Figures 1 to 7 The disclosed invention will be better understood from the following detailed description of exemplary non-limiting illustrative embodiments of the side stick grip of the accompanying drawings, in which:

[0020] Figure 1 and Figure 2 They are the top inner perspective view and the top outer perspective view;

[0021] Figure 3 and Figure 4 They are the inner and outer elevation views respectively.

[0022] Figure 5 and Figure 6 The rear elevation and front elevation are respectively; and

[0023] Figure 7 This is its top view. DETAILED DESCRIPTION

[0024] exist Figures 1 to 7 An exemplary side stick grip 10 for use with a pilot's right hand according to an embodiment of the present invention is depicted in several views of FIG. 1 , which substantially excludes cross-axis control coupling about more than three control axes. However, it should be understood that a side stick grip 10 may be provided. Figures 1 to 7The mirror image of the exemplary side stick grip shown in FIG. 1 is a left-hand embodiment and is used by the pilot's left hand. Therefore, the following discussion will similarly apply to the side stick grip 10 used by the right or left hand.

[0025] The sidestick grip 10 includes a lower grip section 12 extending upwardly from a lower wrist support platform 14, the lower grip section 12 being sized and configured so that it accommodates hand size anatomy ranging from the 5th percentile female to the 95th percentile male (i.e., configured to comfortably fit approximately 90% of the hand size anatomy of the population). A base section 16 is disposed below the wrist support platform 14 to connect the sidestick grip 10 to a support structure within a cockpit of an aircraft (not shown) to allow movement of the sidestick grip 10 in at least three axes, i.e., in a forward and aft direction (arrows A and B, respectively). f and A a ) to control the pitch of the vehicle about the x-axis, in the inboard and outboard directions (arrow A i and A o ) to control the vehicle's roll about the y-axis, and twisting about the centerline CL of the sidestick grip 10 to control the vehicle's roll about the yaw or z-axis (arrow A y ) of the aircraft yaw (see Figures 1 to 3 The lower grip section 12 is generally cylindrical (e.g., between about 1 and 2 inches in diameter) and is adapted to substantially allow the pilot's palm to rest on the outer circumferential surface, such as Figure 1 The inside portion of the lower grip section includes a profile with recesses 12a-12c that allow the lower three fingers of the pilot's hand (i.e., the fifth finger (little finger), the fourth finger (ring finger), and the third finger (middle finger)) to rest against the recesses when the fingers are wrapped around the front of the lower grip section 12.

[0026] The upper end of the lower grip section is joined to a transition section 18 that transitions the outer surface of the lower grip section 12 to a throttle stick-shaped head section 20. The throttle stick-shaped head section 20 generally includes a transversely oriented semi-cylindrical first head portion 22 and a frusto-conical second head portion 24 that protrudes outwardly from the cylindrical first head portion 22 in an inboard direction. The first head portion 22 includes a concave arcuate guide 26 in which an arcuate segment of a thumb wheel 28 is operatively mounted for arcuate thumb-activated sliding movement in the forward and rearward directions. In this regard, the transition section 18 can be used as a thumb rest when the pilot is not manipulating the thumb wheel 28. Thus, the arcuate segment of the thumb wheel 28 can be slidably moved by the thumb of the pilot when the lower grip section 12 is grasped to control the acceleration / deceleration of the aircraft.

[0027] The lower grip section 12 includes a touch control steering (TCS) button 30 which projects outwardly in an inboard direction and is adapted to be depressed and held by the pilot with the pilot's third finger (middle finger) when required to temporarily disengage the autopilot servo and allow the pilot to manually steer the aircraft. Releasing the TCS button 30 will thereby reengage the autopilot servo in the attitude manually achieved by the pilot during the autopilot servo disengagement. A push-to-talk (PTT) button 32 is provided which projects outwardly in a forward and upwardly inclined direction from the transition section 18 and is adapted to be depressed by the pilot's second finger (index finger) when required to allow radio transmission. When the PTT button 32 is not in use, the pilot may place the second finger (index finger) against a recess 20d contoured on the forward surface of the throttle stick-shaped head section 20 (see Figure 3 ). The quick disconnect button 34 is located outboard of the throttle stick-shaped head section 20 and tilted outwardly at a height lower than the height of the arcuate section of the thumb wheel 28. The thumb of the pilot can thus be moved between the thumb wheel 28 and the quick disconnect button 34 in order to disconnect the autopilot servo system and allow the pilot to have continuous manual flight control via the side stick grip 10.

[0028] Importantly for the sidebar grip 10 of the embodiment described and illustrated herein, the lower grip section 12 is inclined at an angle α in a forward direction relative to a transverse plane P1 defined by the x-axis and the z-axis, and is also inclined at an angle β in a medial direction relative to a longitudinal plane P2 defined by the y-axis and the z-axis (see FIG. Figure 1 , Figure 3 and Figure 5 ). Merely by way of example, the angle α may be 10°-17°, typically 12°-15°, such as 13°±1°, relative to the transverse plane P1, while the angle β may be 2°-10°, typically 4°-6°, such as about 5°±1°, relative to the longitudinal plane P2. Thus gripping the inclined side stick grip 10 will be ergonomically comfortable for the pilot. Furthermore, the centerline CL of the side stick grip 10 intersects the yaw axis (axis z) of the aircraft substantially at the grip reference point (GRP) (see Figure 3 and Figure 5 This substantially coincident alignment of the GRP with the yaw axis (axis z) thereby provides a substantially coincident alignment of the GRP of the side stick grip 10 with the yaw axis of rotation (arrow A). y ) provides a zero moment arm between the GRP and the yaw axis (axis z). This substantially coincident alignment of the GRP with the yaw axis (axis z) in turn prevents sidestick movement in the fore / aft and lateral / medial directions (arrow A f / A a and A o / A i) are coupled between the cross axes, thereby allowing the side handle 10 to be rotated in a clockwise / counterclockwise direction (arrow A) independently of the side handle 10. y ) to control the aircraft's pitch and roll axes (x-axis and y-axis, respectively). In this way, the sidestick handle 10 can be manually manipulated to control the aircraft in the pitch and roll axes (x-axis and y-axis, respectively) without causing an unintended yaw torque to be applied to the sidestick handle 10 about the yaw axis (z-axis) in the clockwise / counterclockwise direction.

[0029] Although reference is made to specific embodiments of the invention herein, various modifications are contemplated by those skilled in the art. Therefore, it should be understood that the invention is not limited to the disclosed embodiments, but rather, the invention is intended to cover various modifications and equivalent arrangements included within its concept and scope.

Claims

1. A side stick grip allowing control of an aircraft about at least three axes, the side stick grip comprising: a lower grip section adapted to be grasped by a pilot's hand and defining a sidestick central axis; a base adapted to be mounted to an aircraft structure to allow the lower grip section to move in a fore / aft direction and an inboard / outboard direction to allow control of the aircraft about a pitch axis and a roll axis, respectively, and to allow the lower grip section to twist in a clockwise / counterclockwise direction about a yaw axis to allow control of the aircraft about the yaw axis, and wherein The lower grip section defines a grip reference point (GRP) that establishes a theoretical point for applying forces to a sidestick controller about the pitch and roll axes, wherein the yaw axis is substantially coincident with the GRP and the sidestick center axis.

2. The sidebar grip according to claim 1, wherein: The base mounts the sidebar grip to define a forward incline and a medial incline.

3. The sidebar grip according to claim 2, wherein: Forward tilt and backward tilt are relative to the transverse plane and longitudinal plane.

4. The sidebar grip according to claim 3, wherein: The forward inclination is an angle α of 10°-17°, and the rearward inclination is an angle β of 2°-10°.

5. The side stick grip of claim 1, further comprising a throttle stick-shaped head section joined to an upper end of the lower grip section.

6. The sidebar grip according to claim 5, wherein: The throttle lever-shaped head section comprises: a transversely oriented semi-cylindrical first head portion, and A frustoconical second head portion projects outwardly from the cylindrical first head portion in an inboard direction.

7. The sidebar grip according to claim 6, wherein: The first header portion comprises: a concave arcuate guide, and An arcuate segment of the thumb wheel is operatively mounted to the recessed arcuate guide for thumb-activated arcuate sliding movement in forward and rearward directions.

8. The sidebar grip according to claim 5, wherein: The lower grip section includes a contoured recess that allows corresponding fingers of a pilot's hand to rest thereon when grasping the lower grip section.

9. The side stick grip of claim 5, further comprising a transition section joining an upper end of the lower grip section to the throttle stick-shaped head section.

10. The side stick grip of claim 7, further comprising a touch control steering (TCS) button protruding outwardly in an inboard direction and adapted to be pressed by a third finger of the pilot's hand when grasping the lower grip section.

11. The sidestick grip of claim 5, further comprising a push-to-talk (PTT) button projecting outwardly from the transition section in a forward direction and adapted to be pressed by a second finger of the pilot's hand when grasping the lower grip section.

12. The sidebar grip according to claim 11, wherein: The forward surface of the throttle lever-shaped head section includes a contoured recess to allow a second finger of the pilot's hand to rest on the contoured recess.

13. The side stick grip of claim 7, further comprising a quick disconnect button positioned at an outer side of the throttle stick-shaped upper section and inclined outwardly in an outer side direction at a height lower than a height of the arcuate section of the thumb wheel.

14. The sidebar grip according to claim 13, wherein: The lower grip section includes a contoured recess that allows a respective one of a third finger, a fourth finger, and a fifth finger of a pilot's hand to rest on the contoured recess when grasping the lower grip section.

15. The side stick grip of claim 14, further comprising a transition section joining an upper end of the lower grip section to the throttle stick-shaped head section.

16. The sidestick grip of claim 15, further comprising a touch control steering (TCS) button protruding outwardly in an inboard direction and adapted to be pressed by a third finger of the pilot's hand when grasping the lower grip section.

17. The sidestick grip of claim 16, further comprising a push-to-talk (PTT) button projecting outwardly from the transition section in a forward direction and adapted to be pressed by a second finger of the pilot's hand when grasping the lower grip section.

18. The sidebar grip according to claim 17, wherein: The forward surface of the throttle lever-shaped head section includes a contoured recess to allow a second finger of the pilot's hand to rest on the contoured recess.

19. The sidebar grip according to claim 18, wherein: The base mounts the sidebar grip to define a forward incline and a medial incline.

20. The sidebar grip of claim 19, wherein: The forward inclination is at an angle α of 10°-17° relative to the transverse plane, and wherein the medial inclination is at an angle β of 2°-10° relative to the longitudinal plane.

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