Split UAV Autopilot Control for Latency-Tolerant Stability
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Solution Overview
Problem
Conventional UAV autopilot systems face limitations in processing computationally intensive algorithms, leading to reduced accuracy and increased power consumption, with single microcontrollers being insufficient, dual processors increasing power usage, and non-real-time processing introducing latency.
Innovation Solution
A split control system configuration utilizing a real-time low-level microcontroller and a non-real-time high-level microprocessor, where the high-level processor computes complex algorithms and desired body rate values, and the low-level processor generates motor control signals, with a dedicated bus for communication, ensuring stability through a rate damping loop algorithm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single microcontroller is used for UAV autopilot system, then device complexity is reduced, but processing capability for computationally intensive algorithms is insufficient
Solution Approach 1:
The control system is segmented into two distinct processors: a microcontroller handling real-time control tasks and a microprocessor handling computationally intensive navigation algorithms. This segmentation allows each processor to be optimized for its specific function, resolving the contradiction between simplicity and processing capability.
2Productivity
If a combination of microcontroller and microprocessor is used, then processing capability is improved, but ability to handle complexity of estimation and control logics remains limited
Solution Approach 1:
Control logic is segmented by assigning estimation and control algorithms to the microcontroller while navigation algorithms are assigned to the microprocessor. This functional segmentation enables the system to handle complex control logics effectively by distributing computational tasks according to processor strengths.
3Device complexity
If a single microprocessor is used, then device complexity is reduced, but latency is introduced which compromises flight control
Solution Approach 1:
The system segments control tasks by time-criticality: the microcontroller executes real-time control loops with deterministic timing, while the microprocessor handles less time-critical navigation computations. This temporal segmentation eliminates latency in flight control while maintaining system simplicity.
4Productivity
If dual processors are used, then processing capability and real-time performance are improved, but power consumption increases and flight time is affected
Solution Approach 1:
Each processor is assigned specific functions matching its capabilities: the microcontroller handles low-power real-time control, while the microprocessor handles computationally intensive tasks only when needed. This localized functional assignment optimizes power consumption by keeping each processor in low-power states during idle periods.
Data Source
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AI summary
A split control system for UAV incorporating auto pilot is disclosed. Control system comprises a real-time low-level main processor, and a non-real-time high-level co-processor. The co-processor computes desired body rate values and feeds them to the main processor which may be with latency. Main processor computes one or more motor control signals based on the desired body rate values. The main processor also executes a rate damping loop algorithm based on instantaneous body rate values to generate one or more motor control signals to maintain stability of the UAV even in events of latency in desired body rate values from the co-processor. Instantaneous body rate values are either obtained directly from sensors without any latency or obtained by main processor indirectly with negligible latency. Main processor acts as an intermediate between sensors and co-processor by collecting raw sensor data and feeding the data to co-processor.