Working Machine Cooling Control System PID Threshold Integral
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Solution Overview
Problem
Existing working machine cooling control systems face instability and noise issues due to excessive integral component accumulation in PID control, leading to oscillations and prolonged convergence times when adjusting fan rotation speeds.
Innovation Solution
A cooling control system that employs a PID control mechanism with a threshold-based integral control activation, where integral control is only executed when the difference between actual and target rotation speeds is below a threshold, and a gain change processing to adjust control gains based on actual engine speed, preventing excessive integral component accumulation and improving responsiveness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If integral control is continuously executed in PID control to eliminate steady-state error, then the fan rotation speed converges to the target value, but excessive integral component accumulation causes instability and oscillations
Solution Approach 1:
The patent dynamically adjusts the integral control execution based on the current state of the system. When the fan rotation speed is far from the target value, integral control is suspended to prevent excessive accumulation. When the speed approaches the target value (within threshold), integral control is activated to eliminate steady-state error. This dynamic switching resolves the contradiction between achieving precision and maintaining stability.
Solution Approach 2:
The patent changes the control parameter (integral control activation status) based on the error magnitude. By comparing the difference between actual and target rotation speeds against a threshold, the system switches between different control modes. This parameter change strategy allows the system to achieve both precision (through integral control when needed) and stability (by suspending integral control when error is large).
2Measurement precision
If integral control is activated to improve convergence accuracy, then the fan rotation speed reaches the target value more precisely, but the convergence time is prolonged due to oscillations
Solution Approach 1:
The patent implements periodic monitoring of the rotation speed error and switches integral control on and off periodically based on whether the error is within the threshold. This periodic adjustment prevents continuous integral accumulation that causes oscillations, thereby reducing convergence time while still achieving precise control when the system is near the target value.
Solution Approach 2:
The system dynamically transitions between different control states (integral control active/inactive) based on real-time error conditions. This dynamic approach allows the system to quickly respond when far from target (avoiding oscillations) and achieve precise convergence when near target, optimizing both convergence time and precision.
3Productivity
If the cooling fan rotation speed is increased to improve cooling efficiency, then the heat dissipation performance is enhanced, but the noise level and energy consumption increase
Solution Approach 1:
The patent uses feedback control (PID control) to continuously monitor the rotation speed error and adjust the fan speed accordingly. By providing precise control, the system can achieve the required cooling efficiency without excessive speed increases, thereby reducing noise. The feedback mechanism ensures the fan operates at the minimum necessary speed to meet cooling demands.
Solution Approach 2:
The system changes the fan rotation speed parameter dynamically based on cooling demands and control errors. Rather than operating at fixed high speed, the fan speed is adjusted to match actual cooling requirements, improving efficiency while minimizing noise and energy consumption through optimal parameter selection.
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
The solution stabilizes fan rotation speed adjustments, reduces noise, and enhances responsiveness by preventing overshoot and oscillations, ensuring efficient heat management in working machines.
Implementation Method 1
a rotor (22) to be rotated under rotational power of the output shaft, the rotor and the housing, under the agency of a viscous fluid introduced into a gap formed between the rotor and the housing, rotating together
Implementation Method 2
a fan (25) to be rotated under rotational power of the output shaft, a housing (23) on which the fan (25) is attached
Data Source
AI summary
A cooling control system includes a prime mover, a fan to be rotated under rotational power of an output shaft of the prime mover, a housing to which the fan is attached, a rotor to be rotated under rotational power of the prime mover, the rotor and the housing, under the agency of a fluid, rotating together, a fluid setting circuit to determine an injection quantity of the fluid to be introduced into the gap, a fan rotation detection device to detect a fan actual rotation speed, a target rotation obtaining circuit to obtain a fan target rotation speed. The integral controlling circuit does not execute the integral control with a difference between the fan actual rotation speed and a fan target rotation speed being greater than or equal to a threshold, and executes the integral control with the difference being less than the threshold.