Electromagnetic Valve Control With Startup Coefficient Learning
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Solution Overview
Problem
The work vehicle faces challenges in accurately controlling electromagnetic valves immediately after the engine starts, due to unsuitable environmental conditions that affect the feed-forward term, leading to inappropriate PI control.
Innovation Solution
An electromagnetic valve control device is implemented, which includes a control signal generator for feedback control using an environmental coefficient, a coefficient determiner to learn and update the coefficient during a learning period, and an operation limiter to manage valve operations during this period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control using an environmental coefficient is implemented for electromagnetic valve control, then control accuracy improves during normal operation, but control accuracy deteriorates immediately after engine startup due to unsuitable environmental conditions
Solution Approach 1:
The control device performs preliminary determination of the environmental coefficient during a learning period immediately after engine startup, before normal feedback control begins. This preliminary action ensures that the environmental coefficient is appropriate for the current operating conditions from the start, preventing control inaccuracies during the critical startup phase.
Solution Approach 2:
The control device dynamically adjusts the environmental coefficient based on the learning period status. During the learning period, the system determines the coefficient through preliminary action, while after the learning period ends, it transitions to normal feedback control with continuous coefficient adjustment, adapting to changing operating conditions.
2Speed
If the feed-forward term is used in PI control for electromagnetic valve operation, then response speed improves, but control precision deteriorates when environmental conditions are unsuitable
Solution Approach 1:
The environmental coefficient, which serves as the feed-forward term, is determined in advance during the learning period before normal control operations begin. This preliminary determination ensures that the feed-forward term is optimized for the current environmental conditions, allowing fast response without sacrificing precision.
Solution Approach 2:
The system combines feedback control with the pre-determined environmental coefficient as a feed-forward term. The feedback mechanism continuously monitors control accuracy and adjusts the coefficient accordingly during the learning period, while maintaining fast response through the feed-forward component during normal operation.
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
This solution enables accurate generation and application of control signals to the electromagnetic valves, ensuring precise control even at the initial stages of engine startup, by determining an appropriate environmental coefficient corresponding to the current state.
Implementation Method 1
electromagnetic valve control device configured to control an angle of a swash plate of a hydrostatic, continuously variable transmission device with use of at least one electromagnetic valve
Data Source
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AI summary
An electromagnetic valve control device includes: a control signal generator (88) configured to, through feedback control involving an environmental coefficient (95), generate a control signal intended for the at least one electromagnetic valve (52A, 52B) and corresponding to a target electric current value (92); a coefficient determiner (86) configured to determine the environmental coefficient (95) during a learning period extending from a start of the drive section (4) over a predetermined time length; and an operation limiter (89) configured to limit respective operations of the at least one electromagnetic valve (52A, 52B) and the gear transmission (31) during the learning period.