Fluidic Flight Control Response Linearization Using Mass-Flow Control
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Solution Overview
Problem
Conventional fluidic control systems for vehicles, such as aircraft and underwater vehicles, face challenges due to non-linear relationships between control inputs and fluid mass-flow/pressure delivery, which complicates the control of fluidic control effectors and requires sophisticated control systems to account for flight conditions and engine throttle settings, making it difficult to achieve linear responses similar to conventional control surfaces.
Innovation Solution
A vehicle control system that includes a controller configured to receive vehicle control inputs and condition data, determining the required fluid mass-flow to achieve a demanded manoeuvre while providing a substantially linear relationship between the input and the manoeuvre effect, by processing data from sensors and using algorithms to adjust control valve positions and fluid pressures, effectively making fluidic control effectors behave like linearly responding devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional control surfaces are used, then linear control response is achieved, but device complexity and number of moving parts increase
Solution Approach 1:
The patent replaces conventional mechanical control surfaces (ailerons, elevators, rudders) with fluidic control effectors that use high-speed jets to manipulate airflow and generate aerodynamic forces. This substitution eliminates numerous moving parts, hinges, and actuation mechanisms while maintaining control authority through fluid dynamic interactions between the jets and external airflow.
Solution Approach 2:
The invention employs pneumatic systems by using high-pressure gas jets (typically from engine compressor bleed air) as the control mechanism. The fluidic control effectors utilize compressed gas to create coherent jets that interact with the external airflow over the aircraft, generating lift, drag, and moment forces without any moving mechanical parts.
2Device complexity
If fluidic control effectors are used, then device complexity is reduced, but control linearity deteriorates due to non-linear mass-flow relationships
Solution Approach 1:
The patent incorporates feedback control systems that continuously monitor flight conditions (airspeed, altitude, angle of attack, throttle setting) and adjust the mass-flow rates to the fluidic control effectors accordingly. This feedback mechanism compensates for the non-linear relationships between control inputs and aerodynamic responses, maintaining linear control characteristics across varying flight conditions.
Solution Approach 2:
The invention dynamically adjusts operating parameters (mass-flow rate, jet pressure, injection timing) of the fluidic control effectors based on real-time flight conditions. By changing these parameters in response to varying airspeed, altitude, and throttle settings, the system maintains optimal control linearity and effectiveness throughout the aircraft's operating envelope.
3Measurement precision
If sophisticated control systems are used to account for flight conditions, then control accuracy is improved, but system complexity and weight increase
Solution Approach 1:
The patent integrates the control system with existing aircraft systems, particularly the engine control and flight management systems. The fluidic control effector control logic is incorporated into the existing flight control computer, allowing a single control system to manage both conventional flight control and fluidic control functions, thereby avoiding duplication and reducing overall system complexity.
Solution Approach 2:
The control system utilizes data already available from the aircraft's sensor suite and existing flight management systems to regulate the fluidic control effectors. By self-servicing with existing flight condition data (airspeed, altitude, throttle position) without requiring additional dedicated sensors or complex independent control systems, the invention maintains control accuracy while minimizing system complexity and weight.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution simplifies the control of fluidic control systems by providing a linear response to control inputs, reducing system complexity and allowing existing autopilot systems to function without modification, while reducing weight, volume, and maintenance requirements.
Implementation Method 1
determine a fluid mass-flow for the at least one fluid control effector based on the received vehicle control input and the condition data, wherein the relationship between the fluid mass-flow and the vehicle control input is substantially non-linear
Implementation Method 2
The high-pressure fluid the passes via a control valve to the fluidic control effector, such as a flight control nozzles (slots/orifices) where it is ejected from the surface of the aircraft into the airflow it is intended to influence
Implementation Method 3
In the case of 'circulation control' air is blown through slots over a curved surface located in the trailing edge of a lifting surface (usually a wing, but it is equally applicable to tails and fins) to change the local flow characteristics in that region
Implementation Method 4
In the case of fluidic thrust vectoring the injection of gas (usually compressor bleed air or bypass air) takes place through slots or holes within the exhaust nozzle of the jet engine. Combined with appropriate shaping of the nozzle geometry this fluid injection causes an asymmetry in the jet flow causing it to be deflected (vectored)
Data Source
AI summary
A vehicle control system (110) for use with at least one fluidic control effector (102) for a vehicle, the vehicle control system (110) comprising a controller (110), wherein the controller is configured to: receive a vehicle control input indicating a demanded vehicle manoeuvre, wherein the input is further configured to receive condition data; determine a fluid mass-flow for the at least one fluid control effector based on the received vehicle control input and the condition data, wherein the relationship between the fluid mass-flow and the vehicle control input is substantially non-linear; and output data relating to the determined fluid mass-flow to effect the demanded vehicle manoeuvre, wherein the fluid mass-flow is determined to provide a substantially linear relationship between the vehicle control input and the effected demanded vehicle manoeuvre.