UAV Flight Control Switching Between Sensed and Commanded Speed

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Solution Overview

Problem

Unmanned aerial vehicles (UAVs) face challenges in accurately measuring airspeed due to misalignment between their forward aerodynamic axis and flight vector, particularly during transitions between hover and cruise modes, leading to loss of control authority and inefficient flight.

Innovation Solution

The system uses a 'commanded speed' as a reference point for flight control decisions instead of sensed airspeed, ensuring appropriate thrust and torque allocation, even when airspeed measurements are unreliable, by calculating a commanded speed based on the vehicle's intended velocity and lateral components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensed airspeed is used to inform flight control decisions, then flight control accuracy is improved under normal conditions, but control authority is lost when airspeed sensor measurements are unreliable due to misalignment between forward aerodynamic axis and flight vector

Engineering Contradiction:

Improveairspeed measurement accuracyVSAvoidcontrol authority during misaligned flight states

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary system that combines commanded speed information with sensed airspeed data. When the airspeed sensor becomes unreliable due to misalignment, the commanded speed serves as a mediator to maintain control authority. The flight control system uses the commanded speed as a substitute reference, allowing continuous control decisions without complete loss of authority during misaligned flight states.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system prepares for potential sensor failure by having commanded speed information ready as a backup reference. Before the airspeed sensor fails or becomes unreliable, the control system already has an alternative reference (commanded speed) prepared. This beforehand preparation ensures that control authority is maintained without interruption when misalignment occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If commanded speed is used instead of sensed airspeed, then control authority is maintained during misaligned flight states, but control precision may be reduced when airspeed measurements are reliable

Engineering Contradiction:

Improvecontrol authority during misaligned flight statesVSAvoidflight control precision under normal conditions

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic switching mechanism that adapts the control reference based on flight conditions. When the vehicle is properly aligned and airspeed measurements are reliable, the system uses sensed airspeed for precise control. When misalignment occurs and sensor reliability deteriorates, the system dynamically switches to using commanded speed. This dynamic adaptation allows the system to optimize between precision and reliability based on real-time flight conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the reference parameter used for control decisions based on flight state. Under normal conditions, sensed airspeed is the reference parameter. When misalignment is detected or suspected, the system switches to using commanded speed as the reference parameter. This parameter change allows the system to maintain control authority across different flight states while minimizing the impact on control precision during reliable operation.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If airspeed sensor is used for flight control decisions, then thrust and torque allocation is optimized under normal flight conditions, but inefficient flight and loss of control authority occurs during transitions between hover and cruise modes

Engineering Contradiction:

Improveflight efficiency under normal conditionsVSAvoidcontrol authority during mode transitions

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system dynamically adapts its control reference based on the flight mode and alignment status. During transitions between hover and cruise modes, when misalignment is likely, the system switches to using commanded speed. During stable normal flight conditions, it uses sensed airspeed for optimized thrust and torque allocation. This dynamic adaptation ensures reliable control authority throughout all flight phases while maintaining flight efficiency during normal operation.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11507115B2Contingent use of commanded speed in lieu of sensed airspeed to inform flight control decisions

Publication Date: 2022.11.22 WING AVIATION LLC

AI summary

A technique for controlling an unmanned aerial vehicle (UAV) includes monitoring a sensed airspeed of the UAV, obtaining a commanded speed for the UAV, wherein the commanded speed representing a command to fly the UAV at a given speed relative to an airmass or to Earth, and when the commanded speed is greater than the sensed airspeed, using the commanded speed in lieu of the sensed airspeed to inform flight control decisions of the UAV.