Adaptive Dual-Controller for Engine Disturbance Rejection
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Solution Overview
Problem
Existing feedback control systems in internal combustion engines, such as large diesel engines, struggle to account for non-measurable disturbances, leading to latency and inefficiency in process control due to reliance on assumptions that may become inaccurate over time.
Innovation Solution
Implementing a dual-control system with a primary feedback controller and a secondary feed-forward controller that adapts based on trends in the primary controller's output, using filtering to focus on long-term trends rather than transients, allowing the secondary controller to adjust its transfer function to maintain a neutral output from the primary controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feed-forward control is used to respond quickly to measurable disturbances, then responsiveness is improved, but accuracy deteriorates due to reliance on assumptions that become inaccurate over time
Solution Approach 1:
The patent applies feedback by using the output from the primary feedback controller as a training signal for the secondary feed-forward controller. The secondary controller learns from the errors and adjustments made by the primary controller, allowing it to adapt its transfer function over time to compensate for non-measurable disturbances while maintaining the speed advantages of feed-forward control.
Solution Approach 2:
The secondary feed-forward controller performs self-learning and self-adjustment by automatically adapting its transfer function based on trends in the primary controller's output. This self-service mechanism allows the system to improve its own accuracy over time without external intervention, capturing the essence of adaptive learning while maintaining responsiveness.
2Measurement precision
If feedback control is used to ensure accuracy, then control precision is improved, but latency increases due to the inherent reaction time to measured effects
Solution Approach 1:
The patent implements preliminary action through the secondary feed-forward controller, which proactively adjusts control signals based on learned patterns from the primary controller's output trends. By anticipating required adjustments before they are fully manifested in the feedback loop, the system reduces latency while maintaining accuracy through the adaptive learning mechanism.
3Device complexity
If a fixed transfer function is used in the feed-forward controller, then device complexity is reduced, but adaptability deteriorates due to inability to account for non-measurable disturbances over time
Solution Approach 1:
The patent applies dynamics by making the transfer function of the secondary feed-forward controller adaptive rather than fixed. The transfer function dynamically adjusts based on trends in the primary controller's output, allowing the system to adapt to changing engine conditions and non-measurable disturbances while maintaining reasonable complexity through focused adaptation on key parameters.
Data Source
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AI summary
A control system for an internal combustion engine comprises a primary controller (301), which compares a feedback value to a setpoint value and produces a primary output. The feedback value is an indicator of a measured dynamic quantity in a process (101) in said internal combustion engine. A secondary controller (302) receives an input value and produces a secondary output according to a transfer function. The input value is an indicator of a measurable disturbance affecting the process (101). A combiner (303) receives said primary and secondary outputs and delivers their combination as a control signal to an actuator (104). The secondary controller (302) receives said primary output or a derivative thereof, and adapts said transfer function based at least partly on an aim of maintaining said primary output at a fixed value.