Gyro-less Autopilot Using Accelerometer State Estimates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional autopilots for air vehicles face challenges in withstanding high g-forces during launch, which can damage or destroy gyroscopes used for stabilization, making it difficult and expensive to harden these sensors.
Innovation Solution
A guidance and control system that uses state estimates generated by movement measurement devices, such as accelerometers, to execute guidance commands and control flight vehicles, even in the absence of reliable gyroscope data, by determining control surface commands and effector commands to manipulate control effectors like elevators, ailerons, or rudder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional autopilots use gyroscopes to control flight, then stabilization and control precision are improved, but the system becomes vulnerable to damage from high g-forces during launch
Solution Approach 1:
The patent extracts the vulnerable gyroscope component from the measurement system and replaces it with accelerometers, which are inherently more resistant to high g-forces. This extraction removes the weak link while preserving the essential function of measuring vehicle motion for control purposes.
Solution Approach 2:
The patent creates a computational model (state estimator) that replicates the function of gyroscopes by using accelerometer data combined with a dynamic model of the vehicle. This copying approach allows the system to infer angular rate information from linear acceleration measurements through mathematical processing, eliminating the need for physical gyroscopes.
2Reliability
If gyroscopes are hardened against high g-forces, then sensor reliability is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent replaces expensive, fragile gyroscopes with cheaper accelerometers that can withstand high g-forces without special hardening. While accelerometers may have shorter operational life in extreme conditions, their lower cost and resistance to launch g-forces make them a practical substitute for applications where ultimate longevity is secondary to surviving launch.
Solution Approach 2:
The patent substitutes mechanical gyroscopic sensors with a combination of accelerometer sensors and computational algorithms. This replacement eliminates the need for mechanically hardening gyroscopes, as the computational approach naturally handles the high-g environment through mathematical modeling rather than physical reinforcement.
3Ease of manufacture
If the system uses only accelerometers without gyroscopes, then sensor hardening cost is reduced, but measurement precision for rotational motion decreases
Solution Approach 1:
The patent uses a state estimator that computationally copies the functionality of gyroscopes by processing accelerometer data through a dynamic model of the vehicle. This mathematical copying allows the system to derive accurate angular rate estimates from linear acceleration measurements, achieving gyroscope-level precision without the cost and vulnerability of physical gyroscopes.
Solution Approach 2:
The patent changes the measurement parameters by using accelerometers (measuring linear acceleration) instead of gyroscopes (measuring angular velocity). Through the state estimator and dynamic model, the system transforms these different parameter measurements into accurate estimates of rotational motion, effectively converting linear acceleration data into angular rate information through mathematical relationships.
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
Enables stable flight control of vehicles subjected to high g-forces without relying on functional gyroscopes, providing a cost-effective and reliable backup system for navigation.
Implementation Method 1
receiving a movement measurement from a movement measurement device
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An autopilot for a flight vehicle is described herein. Various configurations of the autopilot may be used in a gyro-less guidance and control system, which can be designed based on translational acceleration measurements only. In other configurations, the one or more components of the autopilot may be used as a backup to primary components of a guidance and control system. The autopilot may use state estimates to determine effector commands to control a flight vehicle.