EGR Valve Motor Control via Feedforward and PID Terms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing EGR valve control systems face challenges in maintaining stable response characteristics when the target opening is frequently changed, leading to insufficient follow-up capability and delays in response.
Innovation Solution
The EGR valve control system employs a motor control apparatus that computes an integral term based on the deviation between the target and actual positions, a proportional term based on the actual position change, a derivative term based on the actual position, and a feedforward term based on the target position change, and calculates the drive duty by adding and subtracting these terms to achieve stable control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If usual PID control is used when deviation is small to prioritize stability, then control stability is improved, but response time increases causing delay
Solution Approach 1:
The control system dynamically adjusts the control strategy based on the magnitude of deviation. When deviation is large, feedforward control is applied for fast response; when deviation is small, PID control is applied for stability. This dynamic switching resolves the contradiction between stability and response speed.
Solution Approach 2:
Feedforward control computes the required motor output in advance based on the target opening position, allowing the system to anticipate and prepare for the required action before the deviation becomes significant. This preliminary action reduces the overall response time while maintaining stability through subsequent PID control.
2Speed
If feedforward control is increased to improve response, then response speed is improved, but stability deteriorates causing overshooting
Solution Approach 1:
The system applies feedforward control partially - only when the deviation is large. When deviation is small, the system switches to PID control which provides sufficient action for stability. This partial application of feedforward control avoids overshooting while maintaining fast response when needed.
Solution Approach 2:
The control system dynamically adjusts the control strategy based on the magnitude of deviation. When deviation is large, feedforward control is applied for fast response; when deviation is small, PID control is applied for stability. This dynamic switching resolves the contradiction between stability and response speed.
3Speed
If PID control parameters are adjusted for fast response, then response time is reduced, but control stability deteriorates
Solution Approach 1:
The control system dynamically adjusts the control strategy based on the magnitude of deviation. When deviation is large, feedforward control is applied for fast response; when deviation is small, PID control is applied for stability. This dynamic switching resolves the contradiction between stability and response speed.
Data Source
AI summary
An EGR valve control system includes a motor 5 exercising the opening and closing control of an EGR valve; a sensor 6 detecting the actual opening position of the EGR valve; and a motor control apparatus (control arithmetic section 1) computing a drive duty of the motor 5 based on a target opening position of the EGR valve and the actual opening position thereof detected by the sensor 6; and the control apparatus is arranged such that the control arithmetic section 1, when a target opening position of the EGR valve is set, computes an integral term based on the deviation between the target opening position and the actual opening position of the EGR valve, a proportional term and a differential term based on the change of the actual opening position of the EGR valve, and a feedforward term based on the change of the target opening position, respectively, and the control arithmetic section further exercises the opening and closing control of the EGR valve by computing the drive duty of the motor 5 by performing addition and subtraction on the computed integral term, proportional term, differential term, and feedforward term.