UAV Gimbal High Bandwidth Control for Vibration Isolation
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Solution Overview
Problem
Existing mechanical rotary stabilization systems for image sensors in UAVs face challenges in minimizing natural frequency to isolate high-frequency disturbances while maintaining stability, as brushless motor gimbals lack sufficient power and are prone to noise, especially when dealing with small amplitude and high-frequency movements, and adding mass to reduce natural frequency is undesirable due to weight and size constraints.
Innovation Solution
A gimbal system actuated by brushless motors driven by a high bandwidth operational amplifier or linear drive circuit, which minimizes stiffness and maintains passive isolation of high-frequency disturbances, using a network of bi-polar junction transistors or a high bandwidth linear drive circuit to stabilize image sensors across multiple axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mass is added to the stabilized platform to lower the natural frequency, then passive isolation of high frequency disturbances is improved, but weight and size increase which deteriorates flight performance and endurance
Solution Approach 1:
The patent changes the control parameters of the brushless motor gimbal by implementing a high bandwidth control loop with updated motor control algorithms. This transforms the system's dynamic characteristics, effectively lowering the natural frequency without adding physical mass, thereby resolving the contradiction between isolation performance and weight.
2Reliability
If stiffness of the system is minimized to achieve low natural frequency, then passive isolation of high frequency disturbances is improved, but stability and power to drive the system deteriorates
Solution Approach 1:
The patent replaces the traditional mechanical stiffness-based isolation approach with an active control system. The high bandwidth operational amplifier circuit and updated motor control algorithms provide the necessary stabilization power electronically, eliminating the need to minimize mechanical stiffness and resolving the contradiction between isolation and driving power.
3Productivity
If brushless motors are used to actuate the gimbal, then performance is improved compared to servo motors, but noise in the sensor increases making it challenging to sense small amplitude and high frequency movements
Solution Approach 1:
The patent implements a high bandwidth feedback control loop that continuously monitors the gimbal's position and movements. The updated motor control algorithms process this feedback signal with enhanced noise filtering and signal processing capabilities, enabling the system to detect and respond to small amplitude and high frequency movements despite the presence of brushless motor noise.
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
The solution effectively stabilizes image sensors by reducing noise and maintaining stability across various frequencies, enhancing the quality of captured images by minimizing the natural frequency and avoiding the need for additional mass, thus improving flight performance and endurance.
Implementation Method 1
brushless motors driven by a high bandwidth operational amplifier or linear drive circuit
Implementation Method 2
using a network of bi-polar junction transistors or a high bandwidth linear drive circuit
Data Source
AI summary
Embodiments discussed herein provide improved control of an unmanned aerial vehicle camera gimbal. In some embodiments, a linear control circuit is described that uses an operational amplifier that allows the system to retain its passive isolation of high frequency disturbances.