Sidestick Grip Layout for Minimal Cross-Axis Yaw Coupling
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Solution Overview
Problem
Existing sidestick grips for aircraft with three or more axes suffer from cross-axis control coupling, where inputs on one axis unintentionally activate other axes, due to the mismatch between control force and displacement sensitivity and the ergonomic design limitations.
Innovation Solution
The sidestick grip design aligns the Grip Reference Point (GRP) with the yaw axis of rotation, minimizing unintentional yaw torque when controlling pitch and roll axes, and incorporates ergonomic cants and contoured surfaces to enhance pilot comfort and control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the Grip Reference Point is located far from the yaw axis of rotation to enable pitch and roll control, then pitch and roll control capability is improved, but cross-axis coupling to the yaw axis increases causing unintentional yaw movement
Solution Approach 1:
The patent extracts the harmful yaw moment component by repositioning the Grip Reference Point to coincide with the yaw axis of rotation. This removes the moment arm that previously caused unintentional yaw coupling when pitch and roll forces were applied, thereby eliminating the harmful cross-axis effect while preserving pitch and roll control capability
Solution Approach 2:
The patent changes the spatial dimension of the Grip Reference Point location from a position offset from the yaw axis to a position coincident with the yaw axis. This dimensional repositioning in the radial direction eliminates the moment arm length, thereby preventing the generation of unwanted yaw torque while maintaining control authority in pitch and roll axes
2Object-generated harmful factors
If spring pre-load or breakout force in the yaw axis is increased to minimize cross-axis control coupling, then cross-axis coupling is reduced, but control difficulty increases when small directional inputs are desired
Solution Approach 1:
The patent removes the source of cross-axis coupling by relocating the Grip Reference Point to the yaw axis, thereby eliminating the need for high spring pre-loads to compensate for moment arm-induced yaw torque. This extraction of the harmful moment arm allows for reduced breakout forces while maintaining control coupling minimization
Solution Approach 2:
The patent changes the critical parameter of Grip Reference Point location from an offset position to a coincident position with the yaw axis. This parameter change fundamentally alters the torque calculation by making the moment arm zero, thereby reducing the required breakout force for yaw control while preventing cross-axis coupling
3Object-generated harmful factors
If an almost vertical grip design is used to minimize cross-axis coupling, then cross-axis control problems are reduced, but ergonomic comfort deteriorates
Solution Approach 1:
The patent extracts the cross-axis coupling problem by repositioning the Grip Reference Point to the yaw axis, thereby decoupling the ergonomic grip angle from the cross-axis coupling issue. This allows the grip to be angled for ergonomic comfort while the coincident GRP position prevents unwanted yaw torque generation
Solution Approach 2:
The patent employs asymmetric positioning of the Grip Reference Point relative to the sidestick structure, placing it specifically at the yaw axis location. This asymmetric arrangement allows the grip to be oriented at ergonomic angles while the GRP position ensures that forces applied at various grip orientations do not generate unwanted yaw moments
Data Source
AI summary
Sidestick grips are disclosed which minimize cross-axis control coupling about three or more control axes, wherein one of the control axes provides directional (yaw) input by twisting the grip in clockwise/counterclockwise directions. Minimizing cross-axis control according to the embodiments disclosed herein is accomplished principally by having the Grip Reference Point (GRP) (i.e., the theoretical point of application of pitch and roll forces) of the sidestick grip to be substantially coincident with the yaw axis of rotation. By providing the GRP substantially coincident with the yaw axis of rotation, unintentional yaw torque is minimized when control input is exerted on the sidestick in the pitch and roll axes.