Hydraulic Actuator Pressure Control via Speed-Adaptive Amplifier
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Solution Overview
Problem
Existing control methods for hydraulic actuators in plastic injection molding machines experience a decline in control quality when the speed of the electric motor is reduced, leading to increased control deviations and worse damping, making it difficult to maintain consistent performance across different speeds.
Innovation Solution
A method and control device that adjusts the properties of the control amplifier, including gain and differentiating coefficients, based on the speed signal to maintain constant control quality and stability, ensuring that loop gain and damping remain consistent even at reduced speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the speed of the electric motor is reduced to adapt to different work steps, then energy efficiency is improved, but control quality deteriorates
Solution Approach 1:
The control amplifier's properties are made dynamically adjustable based on motor speed. The controller adapts the amplifier characteristics in real-time according to the current speed signal, enabling the system to maintain optimal control quality across different operating speeds while preserving energy efficiency benefits.
Solution Approach 2:
The invention changes the parameters of the control amplifier based on the motor speed. By adjusting the amplifier characteristics as a function of speed, the system compensates for speed-related control quality degradation while maintaining the energy efficiency gains from variable speed operation.
2Loss of energy
If the speed of the electric motor is reduced, then energy consumption is decreased, but loop gain decreases leading to increased control deviation
Solution Approach 1:
The control amplifier's parameters are changed as a function of motor speed. When speed decreases, the amplifier parameters are adjusted to compensate for the resulting loop gain reduction, thereby maintaining control precision and minimizing control deviation while preserving energy consumption benefits.
3Use of energy by moving object
If the speed of the electric motor is reduced, then energy efficiency is improved, but damping becomes worse making disturbances more noticeable
Solution Approach 1:
The damping characteristics of the control system are made dynamically adjustable through the speed-dependent control amplifier. As motor speed changes, the amplifier adapts its properties to maintain consistent damping performance, ensuring disturbances are effectively suppressed while preserving energy efficiency.
Solution Approach 2:
The control amplifier parameters are changed based on motor speed to compensate for damping degradation at reduced speeds. This dynamic parameter adjustment maintains stable damping characteristics across the full speed range while allowing energy-efficient variable speed operation.
4Device complexity
If a fixed control amplifier is used, then device complexity is reduced, but control quality varies with speed
Solution Approach 1:
Rather than using multiple fixed amplifiers for different speed ranges, the invention employs a single dynamic control amplifier whose properties automatically adapt to the current operating speed. This approach maintains control quality consistency without significantly increasing device complexity.
Solution Approach 2:
The control amplifier is designed to perform multiple functions across different speed ranges by dynamically adjusting its properties. This universal amplifier replaces what would otherwise require multiple specialized amplifiers, maintaining control quality consistency while avoiding excessive complexity multiplication.
Data Source
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AI summary
The method involves supplying a hydraulic actuator (11) with an amount of pressure fluid by a variable displacement pump (13) that is operated by a speed-controlled motor (14) e.g. electro motor. A signal, which represents pressure of a pressure fluid, is fed back to a pressure controller (10) for controlling the variable displacement pump. The motor is operated based on a speed signal, and characteristics of a control amplifier of a pressure regulator are varied according to the speed signal. Amplification of the control amplifier is adjusted based on the speed signal. An independent claim is also included for a control device for controlling a pressure fluid supply for a hydraulic actuator of a machine.