UAV Engine Timing Redundancy via Alternator Signal Processing
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Solution Overview
Problem
Unmanned aerial vehicles (UAVs) face challenges in achieving redundancy in engine timing position systems without significantly increasing weight and cost, as duplicating components for redundancy can compromise performance and range, and existing solutions either require additional components or add weight and cost.
Innovation Solution
A method that generates a secondary timing position signal from an alternator-derived electrical signal to provide redundancy in the engine timing system, eliminating the need for a second crankshaft or camshaft position sensor, thereby maintaining engine operation in case of primary sensor failure without adding weight or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second crankshaft or camshaft position sensor is added to provide redundancy, then reliability is improved, but weight and device complexity increase
Solution Approach 1:
The patent creates a virtual copy of the primary timing position signal by processing the alternator signal through a microcontroller. Instead of physically duplicating the sensor, the system generates a secondary timing signal that mirrors the functionality of the primary sensor, thereby providing redundancy without the weight penalty of additional physical sensors.
Solution Approach 2:
The patent replaces the mechanical/sensor-based redundancy approach with an electronic signal processing solution. The alternator signal, which is already present in the system for electrical power generation, is electronically processed to create a timing position signal, substituting the need for a second physical position sensor with an electronic derivation method.
2Reliability
If a second crankshaft or camshaft position sensor is added to provide redundancy, then reliability is improved, but device complexity increases
Solution Approach 1:
The alternator serves multiple functions: it generates electrical power for the UAV and simultaneously provides a signal source for the secondary timing position signal. This multi-functionality reduces the need for dedicated redundancy components, as the same alternator signal is used for both power generation and timing redundancy.
Solution Approach 2:
The microcontroller creates a virtual copy of the primary timing signal by processing the alternator signal. This software-based signal copying approach is less complex than hardware-based sensor duplication, as it leverages existing electronic components and processing capabilities already present in the UAV's engine control system.
3Reliability
If additional robust components are used to withstand harsh environmental conditions, then reliability is improved, but weight and cost increase
Solution Approach 1:
The system uses the alternator's own output signal to generate the secondary timing position signal. The alternator, which is already a robust component designed to withstand harsh environmental conditions during flight, serves its own redundancy purpose by providing a signal that can be processed into a backup timing signal, eliminating the need for additional robust components.
Solution Approach 2:
The patent changes the parameter domain from physical sensor redundancy to signal domain redundancy. By processing the alternator's electrical signal parameters through the microcontroller, the system creates a timing position signal that is as reliable as physical sensors would be, but without the weight and cost of additional robust physical components.
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 approach allows for lightweight redundancy in the engine timing system, enabling UAVs to maintain operation and safely return to base in case of primary sensor failure, while avoiding the weight and cost penalties associated with duplicating sensors or adding additional components.
Implementation Method 1
the secondary timing position determining means generating the secondary timing position signal from an alternator derived electrical signal
Data Source
AI summary
Redundancy in engine timing position sensing maintains a UAV operational in the event of failure of a primary engine timing position sub-system. The redundancy avoids duplication of the primary crankshaft timing position sensing components, and avoids adding weight, cost and component complexity. Conditioned (square) waveform(s) (102) is/are created from respective sinusoidal waveform(s). Each consecutive leading edge (103a) and trailing edge (103b) of the pulses of the square waveform (102) is derived from the crossing of the zero voltage value by consecutive sinusoidal waveforms A,B,C (e.g. Voltage (V) vs Time (t) or angular degrees). The square pulse waveform (102) is output (104) to a microcontroller (106) to create and output a pseudo crankshaft timing position signal (108) to be used by an ECU to determine ignition and fuel injection events in the event that the primary timing signal from the crankshaft position sensor (CPS) has failed. The signal (108) output to the ECU can have a missing pulse (116) (i.e. indicative of a TDC position of the engine crankshaft) as well as multiple square pulses (114) corresponding to the pulses of the initial square pulse waveform (102). The waveform signal (108) is therefore derived from the alternator waveform signal(s) and provides a pseudo crankshaft timing position signal in the event of failure of the primary or initial CPS signal.