Tiltrotor Flight Control Computer Sidestick Input Conversion
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Solution Overview
Problem
Conventional flight control systems for eVTOL aircraft lack efficient mechanisms to transition seamlessly between hover and cruise modes, and to manage aircraft position and velocity effectively using sidestick controls, leading to increased pilot workload and potential unsafe mode transitions.
Innovation Solution
A flight control computer system that converts sidestick inputs into specific commands for translational and yaw rate controls, with adaptive threshold settings and modes to manage transitions between hover and cruise modes, utilizing a dual sidestick configuration with soft and hard stops for intuitive and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional flight control systems use mechanical linkages or basic fly-by-wire systems, then the aircraft can be controlled, but the transition between hover and cruise modes becomes complex and increases pilot workload
Solution Approach 1:
The flight control computer continuously monitors aircraft state (hover vs. cruise mode) and automatically adjusts the interpretation of sidestick inputs. During hover mode, longitudinal sidestick input controls fore-aft translational rate; during cruise mode, the same input controls acceleration. This dynamic feedback mechanism eliminates the need for manual mode switching and reduces pilot workload while managing system complexity through automated control logic.
Solution Approach 2:
The control system dynamically adapts its characteristics based on flight phase. The flight control computer detects the current mode (hover or cruise) and automatically reconfigures the control law mapping between sidestick inputs and aircraft responses. This dynamic adaptation allows a single unified control interface to serve multiple flight regimes without increasing pilot workload or requiring complex manual intervention.
2Reliability
If the flight control system allows full range of sidestick motion, then the aircraft responds to all pilot inputs, but unsafe mode transitions may occur
Solution Approach 1:
The system preemptively prevents unsafe mode transitions by implementing soft stops that limit sidestick motion to a restricted range during transition phases. Before an unsafe transition can occur, the control system detects the approaching boundary and applies a counteracting force through the sidestick mechanism, pushing the control input back within safe limits. This preliminary anti-action ensures reliability by blocking potentially dangerous transitions before they can execute.
Solution Approach 2:
The flight control computer dynamically adjusts the effective control range parameter based on flight phase. During hover-to-cruise transitions, the system modifies the maximum allowable sidestick deflection angle or force threshold, effectively changing the adaptability parameter. This allows full control versatility when safe, while automatically reducing the control range when transitioning through unsafe zones, thereby maintaining reliability without permanently sacrificing adaptability.
3Reliability
If hard stops are used to limit inceptor movement, then unsafe positions are prevented, but the control system becomes less flexible
Solution Approach 1:
The system replaces static hard stops with dynamic soft stops that adapt their characteristics based on flight phase. During hover mode, the soft stop allows full lateral sidestick motion for yaw control. During cruise mode, the same soft stop mechanism dynamically restricts lateral motion to prevent unsafe bank angle transitions. This dynamic behavior maintains reliability by preventing unsafe positions while preserving control flexibility when appropriate, avoiding the permanent rigidity of hard stops.
4Ease of operation
If the flight control system automatically manages mode transitions, then pilot workload is reduced, but the system complexity increases
Solution Approach 1:
The flight control computer employs continuous feedback from aircraft state sensors (accelerometers, gyroscopes, airspeed indicators) to automatically detect when transitions between hover and cruise modes are occurring. Based on this feedback, the system autonomously adjusts control laws and parameters without pilot intervention. This feedback-driven automation reduces pilot workload significantly while managing system complexity through well-defined transition detection algorithms and control law switching logic.
Data Source
AI summary
Embodiments are directed to systems and methods for controlling a tiltrotor aircraft using a flight control system. A flight control computer is configured to control aircraft effectors in response to inputs from inceptors. The flight control computer stores instructions for controlling aircraft effectors. The instructions cause the flight control computer to perform the steps of converting a signal representing longitudinal motion of a first inceptor into a fore-and-aft translational rate command for the tiltrotor aircraft; converting a signal representing lateral motion of the first inceptor into a side-to-side translational rate command for the tiltrotor aircraft; converting a signal representing longitudinal motion of a second inceptor into a height rate command for the tiltrotor aircraft; and converting a signal representing lateral motion of the second inceptor to a yaw rate command for the tiltrotor aircraft.