Tilt Rotor Control Using Swash-Angle Feedback to Prevent Motor Stalling
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Solution Overview
Problem
Conventional tilt rotor systems face challenges in efficiently controlling the pre-load mechanism due to high stiffness end stops, leading to difficulties in achieving controlled end stop loads during transitions between vertical and horizontal modes, requiring oversized motors to handle varying loads and risking motor stalling.
Innovation Solution
A drive mechanism using variable displacement hydraulic motors (VDHM) with an intelligent algorithm that monitors and controls swash angle to manage torque and speed, ensuring smooth transitions by limiting swash angle changes, thereby reducing peak loads and avoiding motor stalling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional high-stiffness end stops are used to secure the rotor system in place, then reliability is improved, but control difficulty increases due to difficulty in achieving controlled end stop loads through highly dynamic control
Solution Approach 1:
The patent applies dynamics by making the end stop stiffness variable rather than fixed. The active compliance control system dynamically adjusts the stiffness of the end stop during operation, allowing high stiffness when security is needed and low stiffness when control is needed. This resolves the contradiction by making the system adaptive to different operational requirements.
Solution Approach 2:
The patent changes the parameter of end stop stiffness from a fixed high value to a variable parameter that can be adjusted in real-time. The active compliance control system modifies the stiffness parameter dynamically based on operational phase, enabling both secure positioning and controlled loading without the trade-off present in traditional systems.
2Power
If motors are designed for high dynamic performance against maximum loads during transitions, then power is improved, but device complexity increases and motor stalling risk remains
Solution Approach 1:
The active compliance control system provides beforehand cushioning by actively managing loads during transitions. The controller anticipates peak loads and modulates motor commands to prevent excessive force application, cushioning against the maximum loads that would otherwise require oversized motors. This allows smaller motors to handle transition loads safely.
Solution Approach 2:
The patent implements feedback through the active compliance control system that continuously monitors system state and adjusts motor commands accordingly. This closed-loop control enables precise power management during transitions, allowing smaller motors to deliver high dynamic performance without stalling by responding to real-time feedback rather than relying on oversized design margins.
Data Source
AI summary
A method for driving a tilt rotor between vertical and horizontal using a variable displacement motor controlled in response to a swash angle of the motor measured in a feedback loop. The loop includes an algorithm configured to monitor change in swash angle as the motor speed reduces and the actual tilt position of the rotor pylon approaches the second position and, based on the change and actual tilt position, to limit change in swash angle to be within a predetermined range as a percentage of the operating load.