Nonlinear Fly-By-Wire Control Using Multi-Dimensional Lookup Tables
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Solution Overview
Problem
Traditional fly-by-wire systems for rotorcrafts are less than optimal due to their linear translation of control inputs, which can lead to overcorrection and system failure, especially in dynamic flight conditions, as they do not adequately account for multiple variables such as airspeed, yaw, pitch, roll, and aircraft loading.
Innovation Solution
A nonlinear fly-by-wire system that uses a flight computer with a multi-dimensional lookup table and virtual hardstop to translate control inputs into control surface outputs, considering various factors like airspeed, acceleration, and aircraft loading, to prevent overcorrection and ensure safe operational parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear translation of control inputs is used in traditional fly-by-wire systems, then the system structure is simple, but the system reliability deteriorates due to overcorrection and failure in dynamic flight conditions
Solution Approach 1:
The patent implements dynamic control translation where the relationship between control inputs and control surface outputs changes based on real-time flight conditions. The system adjusts control translations dynamically using multiple variables including airspeed, acceleration, and flight geometry, allowing the control system to adapt its behavior to different operating regimes rather than using fixed linear translation
Solution Approach 2:
The system incorporates feedback mechanisms by continuously monitoring flight conditions (airspeed, acceleration, flight geometry) and using this information to adjust control translations. The control computer queries multiple data sources and uses this feedback to modify control surface outputs appropriately, preventing overcorrection and improving reliability
2Adaptability or versatility
If a linear control translation is used, then the ease of operation is maintained, but the adaptability to different flight conditions deteriorates
Solution Approach 1:
The system changes control parameters dynamically based on flight conditions. It queries data sources for current airspeed, acceleration, and flight geometry, then uses these parameters to adjust control translations through multi-dimensional lookup tables. This allows the system to adapt to different flight regimes (high speed, low speed, high angle of attack, etc.) while maintaining consistent pilot interface
Solution Approach 2:
The control computer serves multiple functions: it processes pilot inputs, queries multiple data sources for flight conditions, performs complex multi-variable calculations, and outputs control commands. The single control computer handles all these diverse functions, making the system universal and adaptable to various flight conditions without requiring separate control systems for different operating modes
3Stability of the object's composition
If control inputs are translated without considering multiple variables, then the device complexity is low, but the stability in dynamic flight conditions deteriorates
Solution Approach 1:
The system transitions from one-dimensional linear control translation to multi-dimensional control translation. It uses multi-dimensional lookup tables that consider multiple variables simultaneously (control input, airspeed, acceleration, flight geometry) to determine appropriate control surface outputs. This dimensional expansion enables stable control across diverse flight conditions by accounting for interactions between multiple parameters
Data Source
AI summary
There is disclosed in one example a flight control computer for a rotary aircraft, including: a first interface to communicatively couple to a flight control input; a second interface to communicatively couple to flight geometry actuators; a data source; a multi-dimensional lookup table including a data structure to correlate flight control inputs to flight geometry actuator outputs according to a third-factor; and circuitry and logic instructions to: receive an input via the first interface; query the data source for the third-factor; query the multi-dimensional lookup table for a control input modifier according to the flight control input and the third-factor; and compute and send via a third interface a flight geometry output according to the control input modifier.