Autothrottle Linear Actuator With Inherent Manual Override
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Solution Overview
Problem
Current aircraft autopilot systems with autothrottle capabilities are limited to large and technologically advanced aircraft due to the physical and mechanical requirements of robust motors and clutches, making it difficult to retrofit or install in existing aircraft, and there is a need for a system that allows easy manual override without disrupting engine control.
Innovation Solution
A compact, lightweight, and simplified autopilot/autothrottle operator arrangement using a linear actuator with a bidirectional stepper motor and bearing assembly that allows for remote activation, eliminating the need for clutches and gears, enabling installation in a wider range of aircraft and providing inherent override capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If robust motors and clutches are used for autothrottle control, then engine control reliability is improved, but system weight and device complexity increase
Solution Approach 1:
The patent replaces traditional mechanical clutch and gear systems with a linear actuator that uses electromagnetic or electrostatic fields to directly move the throttle lever. This substitution eliminates complex mechanical transmission components while maintaining reliable engine control through direct linear motion actuation.
Solution Approach 2:
The invention extracts and removes the clutch and gear mechanisms from the autothrottle system, retaining only the essential linear motion component. By taking out the unnecessary mechanical transmission elements, the system achieves reliable control with reduced complexity and weight.
2Reliability
If robust motors and clutches are installed in aircraft, then autothrottle functionality is achieved, but physical space requirements increase
Solution Approach 1:
The linear actuator replaces bulky mechanical motors and clutches with a compact electromagnetic or electrostatic device that produces linear motion directly. This substitution dramatically reduces the physical volume required for the autothrottle system, enabling installation in aircraft with limited cockpit space.
Solution Approach 2:
The invention transitions from rotational motion (traditional motors) to linear motion (linear actuator), changing the dimensional approach to actuation. This dimensional change allows for a more space-efficient design that can be mounted in compact configurations within the aircraft cockpit.
3Ease of operation
If manual override capability is added to autothrottle system, then pilot control flexibility is improved, but system complexity increases
Solution Approach 1:
The linear actuator system is designed to be inherently overridable by pilot force. The direct linear motion mechanism allows the pilot to manually move the throttle lever against the actuator's resistance without requiring a separate override mechanism. The system serves itself by allowing natural manual intervention while maintaining automated control during normal operation.
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 provides reliable, efficient, and safe autothrottle control with easy manual override, reducing pilot workload and increasing safety by allowing quick manual control of throttles, while also monitoring engine parameters to prevent engine performance deviations and provide haptic feedback.
Implementation Method 1
a linear actuator with a bidirectional stepper motor
Implementation Method 2
an actuator assembly operatively connected to the shaft and to an attachment end of a throttle lever... with a plurality of bearings arranged to apply a thrust force to a longitudinally elongated surface of the shaft
Data Source
AI summary
Aircraft autothrottle system, having a motor to impart rotational movement to a shaft extending from the motor. An actuator is connected to the shaft and to an attachment end of a throttle lever having a control end, opposite the attachment end. The actuator has bearings to apply thrust to a longitudinal surface of the shaft such that the actuator is translated longitudinally along the shaft surface in response to motor-imparted rotation of the shaft. The shaft surface being smoothly continuous and longitudinally unbroken along its elongation to allow the actuator to longitudinally slip along the shaft irrespective of any shaft rotation by the motor when the thrust force exceeds a linear force manually applied at the throttle lever. An electronic controller for the motor to move the throttle lever so the motor moves the actuator assembly along the shaft based on an engine parameter monitored by the controller.