Hybrid Velocity Force Controller for Extrusion Molding
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Solution Overview
Problem
Existing control systems for extrusion molding machines and similar systems cannot maintain a constant force at a constant velocity due to varying viscous drag, which is dependent on velocity and temperature conditions, limiting their ability to control velocity and force in parallel.
Innovation Solution
A controller that periodically outputs a command value calculated from a command pattern and feedback values, incorporating a correction operation unit to adjust the command value based on the relationship between velocity and force errors, ensuring a predetermined relationship between velocity and force, even with changes in viscous drag, using the formula Vc=Vnow+{Dd1(Vd−Vnow)+Md1(Fnow−Fd)} Δt, and setting upper and lower limits for the correction command value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a controller outputs a position or velocity command value to control the position or velocity of a control target, then the position or velocity control is achieved, but the controller cannot control the force in parallel
Solution Approach 1:
The patent combines position/velocity control and force control into a unified control system. The controller integrates both control functions by calculating a corrected command value that incorporates both velocity command and force feedback, allowing simultaneous control of both parameters through a single control loop.
Solution Approach 2:
The controller is designed to perform multiple control functions (position control, velocity control, and force control) through a single integrated system. The correction operation unit universally handles both velocity and force parameters, making the controller adaptable to different control requirements without needing separate control systems.
2Stability of the object's composition
If the controller controls the control target with a constant force at a constant velocity, then the extrusion molding is stable, but the control cannot be maintained when the viscous drag changes with temperature or velocity
Solution Approach 1:
The patent implements feedback control by continuously monitoring the force feedback from the control target and comparing it with the command target value. The correction operation unit uses this feedback to calculate a corrected command value that compensates for changes in viscous drag, maintaining stable control under varying conditions.
Solution Approach 2:
The controller dynamically adjusts the command value based on real-time feedback. Instead of using fixed constant values for force and velocity, the system continuously calculates corrected commands that adapt to changing viscous drag conditions, allowing the control parameters to vary dynamically while maintaining stability.
3Device complexity
If the controller uses a simple velocity control or force control system, then the control system is simple, but it cannot control both velocity and force with a predetermined relationship
Solution Approach 1:
The patent segments the control process into distinct functional units: a command value output unit that generates basic velocity commands, and a correction operation unit that refines these commands based on force feedback. This segmentation allows the system to maintain simplicity in the overall structure while achieving precise velocity-force control through specialized sub-functions.
Data Source
AI summary
The velocity and force of a target is controlled to have a predetermined relationship, independently of changes in the velocity at which the target is driven using a velocity command value and in an external force from the target. A controller controls a control target, driven to generate a predetermined viscous force as a reaction force, by periodically outputting a command value to the control target using a target value calculated from a command pattern for driving the control target and a feedback value from the control target relative to the target value. A correction operation unit obtains a control physical quantity different from the command value, calculates a correction command value based on a relationship between an error of the obtained control physical quantity from its target value and an error of the feedback value from the target value, and outputs the correction command value to the control target.