Antiskid Controller Initialization Using Adaptive Rate Switching
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Solution Overview
Problem
Aircraft braking systems experience a significant delay in transitioning from pressure control to antiskid control, leading to deep initial skids due to the time required for the antiskid controller to converge on an appropriate solution, which affects the efficiency of wheel speed control and increases stop distances.
Innovation Solution
A brake control system that includes a differential reference controller with a delay toggle and switch logic to switch between an initial and running rate, allowing for quicker convergence of the antiskid correction signal by using a higher initial rate initially and transitioning to a lower running rate after a predetermined duration or upon error reduction, thereby improving antiskid control efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the antiskid controller uses a conservative running rate for calculating the antiskid correction signal, then the control stability is improved, but the convergence time increases causing deep initial skids
Solution Approach 1:
The patent applies dynamics by making the rate parameter adaptive rather than fixed. The system transitions from an initial high rate (for fast convergence) to a running low rate (for stability) based on the convergence state of the antiskid correction signal. This dynamic adjustment resolves the contradiction between fast convergence and stable control.
Solution Approach 2:
The patent uses preliminary action by implementing an initial high rate phase before switching to the conservative running rate. This preliminary high-rate phase allows the system to quickly converge during the critical initialization period, preventing deep initial skids, while the subsequent low-rate phase maintains stability during normal operation.
2Productivity
If the brake controller transitions quickly from pressure control to antiskid control, then the stop distance is shortened, but the wheel speed control accuracy decreases causing excessive skidding
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the rate parameter used in antiskid correction signal calculation. The system switches from an initial high rate that enables fast convergence and short stop distance to a running low rate that provides accurate wheel speed control and prevents excessive skidding.
Data Source
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AI summary
An antiskid controller for controlling braking operation of a wheel of a vehicle based on an output signal provided by a wheel speed sensor (32) coupled to the wheel may comprise a delay toggle (310), a switch logic (320) for switching between an initial rate and a running rate, and a linear control (330) used for calculating an antiskid correction signal, wherein the linear control (330) receives one of the initial rate and the running rate, depending on a state of the switch logic (320). The linear control (330) receives the initial rate upon initialization of the antiskid controller. The linear control (330) receives the running rate after a predetermined duration or after the linear control (330) has converged on a desired solution.