PID Controller With Look-Ahead Buffer for Heating Element
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Solution Overview
Problem
Inkjet printing devices face challenges in maintaining the temperature of heating elements within set point thresholds due to long control loop cycle times, leading to delayed system responses and fluctuations, especially in high-throughput printing, which affects the drying process and finishing of printed media.
Innovation Solution
An asymmetric hysteresis-based switching mechanism is introduced to selectively enable or disable power transmission to the heating element based on temperature thresholds, working in conjunction with a PID controller to maintain temperature stability and prevent overheating or underheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PID controller is used to maintain heating element temperature, then temperature control precision is improved, but system response time increases due to long control loop cycle times
Solution Approach 1:
The patent implements preliminary action by using a look-ahead buffer to pre-calculate and store PWM duty cycle values before they are needed. The controller pre-computes control signals based on predicted temperature trends and stores them in a buffer, allowing the heating element to respond immediately when needed without waiting for the standard PID control loop cycle to complete. This eliminates the delay inherent in conventional PID controllers while maintaining temperature precision.
2Loss of time
If control loop cycle time is reduced to improve response speed, then system response time is improved, but temperature control stability deteriorates due to increased fluctuations
Solution Approach 1:
The look-ahead buffer pre-calculates optimal PWM duty cycles based on predicted temperature trajectories, allowing the system to respond quickly without sacrificing stability. By preparing control signals in advance based on trend analysis, the system avoids the oscillations that occur when control parameters are adjusted too frequently.
Solution Approach 2:
The patent implements periodic action through the look-ahead buffer, which operates at a higher frequency than the main PID control loop. The buffer continuously generates and updates PWM duty cycle values at optimized intervals, creating a periodic control signal that maintains temperature stability while enabling faster response to temperature changes.
3Use of energy by moving object
If PWM signals are continuously transmitted to the heating element, then heating efficiency is improved, but temperature fluctuations increase due to delayed system response
Solution Approach 1:
The look-ahead buffer pre-calculates the optimal PWM duty cycle values before they are needed, allowing the system to transmit heating signals at the precise moments when they are most effective. This prevents both overheating and underheating by ensuring that PWM signals are sent proactively rather than reactively, maintaining heating efficiency while eliminating temperature fluctuations.
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 effectively reduces temperature fluctuations and maintains temperature stability within set point thresholds, improving the drying process and reducing the risk of component damage, even in high-throughput printing environments.
Implementation Method 1
receive pulse width modulation signals from a proportional-integral-derivative controller; selectively enable or disable power transmission to the heating element based on the pulse width modulation signals
Implementation Method 2
selectively enable or disable power transmission to the heating element based on temperature thresholds
Data Source
AI summary
In some examples, a system can include: a heating device, a Proportional Integral Derivative (PID) controller and a switching mechanism to selectively enable transmission of signals to the heating device based on a real time temperature in proximity to the heating device, wherein the PID controller is to continuously output pulse width modulation (PWM) signals independent of selective transmission of signals by the switching mechanism.