Control Device Filter Gain Adjustment for Engine Operating Limits
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Solution Overview
Problem
Complex systems, such as engines, face conflicts between adhering to operating limits and responding to setpoints due to poor design knowledge and parameter drift over time, with existing solutions failing to guarantee that critical subsystem parameters remain within their limits.
Innovation Solution
A control device that filters setpoints using a first-order integrator, adjusts the filter gain based on system parameters and operating limits, and applies a gain control factor to prioritize compliance with operating limits, incorporating a Predictive Internal Model for multivariable command generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a saturator is used to limit the rate of change of setpoint, then the rate of change of operating points is slowed down, but critical parameters of subsystems are not guaranteed to remain within operating limits
Solution Approach 1:
The invention implements a feedback mechanism where the actual value of the critical parameter is continuously monitored and compared against its operating limit. The filtered setpoint is then adjusted based on this comparison to ensure the parameter remains within its limit while still progressing toward the desired setpoint. This closed-loop feedback approach guarantees reliability by making real-time adjustments rather than relying on open-loop rate limiting.
Solution Approach 2:
The invention dynamically adjusts the filtered setpoint based on the real-time state of the critical parameter. When the parameter approaches its operating limit, the filtered setpoint is modified to slow down the approach rate. This dynamic adaptation allows the system to optimize between reaching the setpoint quickly and maintaining parameter safety, resolving the contradiction between speed and reliability.
2Productivity
If the filter gain is increased to respond faster to setpoint changes, then the system responds more quickly, but critical parameters may exceed their operating limits
Solution Approach 1:
The system uses dynamic adjustment of the filtered setpoint based on the critical parameter's current value and its operating limit. When the parameter is far from its limit, the filter can operate with higher gain for faster response. When the parameter approaches the limit, the filtered setpoint is automatically adjusted to reduce the drive toward the setpoint, preventing exceedance. This dynamic behavior resolves the contradiction between productivity and reliability.
Solution Approach 2:
The filtered setpoint acts as an intermediary between the desired setpoint and the actual system response. By adjusting this intermediate variable based on the critical parameter's state, the system can achieve fast response when safe and slow down when necessary, without directly limiting the controller's ability to respond. This intermediary approach maintains productivity while ensuring reliability.
3Reliability
If the filter gain is decreased to prevent parameter exceedance, then operating limits are protected, but the system response to setpoint changes becomes slower
Solution Approach 1:
The invention applies local quality by making the filter response characteristic variable rather than uniform. The effective filter gain is adjusted locally based on the critical parameter's proximity to its operating limit. When the parameter is safely within limits, the system responds quickly with higher effective gain. When approaching the limit, the response is locally slowed down. This spatially-variable response characteristic resolves the contradiction between reliability and productivity.
Data Source
AI summary
This device for controlling at least one operating variable of a regulated system comprising: a filter module for filtering at least one setpoint input to the control device, the module using a first order integrator; and a correction module for correcting the variable by servo-control, the module taking account of a measurement of the variable and of the setpoint as filtered by the filter module in order to generate at least one command for the system; a control module suitable for generating a gain control factor α on the basis of at least one parameter of the system and of an operating limit value associated with the parameter; and weighting means for weighting the gain of the filter module as a function of the factor and of the residue between the setpoint and its filtered value.