Brake Actuator Ball Screw Positioning
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Solution Overview
Problem
Aircraft brake systems face challenges in accurately determining the position of the ram within the brake stack, leading to potential delays in brake actuation and safety risks due to insufficient compression or excessive wear, especially when the ram is not in the optimal zero torque or running clearance positions.
Innovation Solution
A brake actuator system comprising a ball screw, ball nut, and position sensor, controlled by a processor that commands the ball nut to translate in specific directions to determine the furthest forward, zero torque, and running clearance positions, ensuring accurate positioning and minimizing delays or wear by detecting malfunctions in position detection systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ram rests on or near the brake disc without engagement, then the brake system is ready for quick actuation, but the position detection becomes inaccurate leading to delays and safety risks
Solution Approach 1:
The system performs preliminary actions by commanding the ball nut to translate in specific directions to establish known reference positions (furthest forward, zero torque, running clearance) before normal operation. This preliminary positioning ensures that when the brake needs to be actuated, the system knows the exact starting position, eliminating detection delays while maintaining readiness for quick response.
Solution Approach 2:
The position sensor continuously provides feedback on the ball nut position, and the processor uses this feedback to determine when reference positions are reached during the preliminary action phase. This feedback mechanism ensures accurate position detection throughout the range of motion, including the resting position, by comparing actual position against commanded position and reference positions.
2Reliability
If the ram is not positioned accurately at zero torque or running clearance positions, then brake actuation may be delayed or cause excessive wear, but implementing precise positioning increases system complexity
Solution Approach 1:
The system uses its own existing components (ball nut, position sensor, processor) to perform the positioning function without requiring external specialized equipment. The processor commands the ball nut to move to specific positions and uses the position sensor feedback to confirm arrival, allowing the system to self-establish accurate reference positions using already-available hardware, thereby minimizing added complexity while improving reliability.
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 system ensures rapid and safe brake actuation by accurately determining and maintaining the ram's position, reducing delays and wear on the brake stack, thereby enhancing safety and operational efficiency.
Implementation Method 1
a brake actuator comprising a ball screw, a ball nut coupled to the ball screw
Implementation Method 2
The position sensor may be a resolver
Data Source
AI summary
A brake actuator system may comprise a brake actuator comprising a ball screw, a ball nut coupled to the ball screw, and a ram coupled to a ram end of the ball nut; a position sensor coupled to the brake actuator; a processor in electronic communication with the brake actuator and the position sensor; and/or a tangible, non-transitory memory configured to communicate with the processor, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the processor, cause the processor to perform operations. The operations may comprise commanding the brake actuator to translate the ball nut in a first direction toward a brake stack; detecting the ram reaching a furthest forward position; and commanding the brake actuator to translate the ball nut in a second direction opposite the first direction for a total retraction distance.