Imaging System Media Positioning via Feedforward Control
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Solution Overview
Problem
Existing imaging systems face challenges in achieving high-quality image positioning due to inaccuracies in media positioning, particularly as the media is unspooled, leading to reduced print quality and increased complexity in mechanical and electrical systems.
Innovation Solution
An imaging system with a controller assembly that uses a combination of feedback and feedforward control loops, where the feedforward component is derived from a time-dependent status parameter representing the current state of the media on the roller, including its radius and inertia, to accurately adjust the actuation command and maintain precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is used to correct positioning errors, then positioning accuracy is improved, but long-term gradual changes in system parameters are not corrected
Solution Approach 1:
The feedforward controller pre-calculates and applies compensation for anticipated positioning errors based on system parameters (media radius, inertia, tension) before the actual positioning operation occurs. This allows the system to proactively counteract long-term gradual changes rather than merely reacting to them after they occur.
2Manufacturing precision
If mechanical construction complexity is increased to satisfy positioning tolerances, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical positioning solutions with a control-based approach. Instead of using more precise mechanical components, the system uses controllers that calculate and apply actuation commands based on media status parameters, substituting mechanical complexity with computational control.
3Measurement precision
If electrical drive specifications are increased to meet positioning requirements, then positioning accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The system dynamically adjusts actuation parameters based on changing media status (radius, inertia, tension) rather than relying on fixed high-specification drive components. The controller modifies actuation commands in real-time to compensate for parameter changes, replacing the need for overly specified electrical drives with adaptive control.
4Reliability
If feedforward control based on status parameters is implemented, then long-term positioning stability is improved, but control system complexity increases
Solution Approach 1:
The system uses the position signal from the feedback loop to update status parameters (media radius, inertia, tension) that are then used by the feedforward controller. This creates an integrated control system where feedback information continuously refines feedforward compensation, managing complexity through information reuse.
Data Source
AI summary
An imaging system includes an imaging station, an actuator for driving a medium roller for controllably displacing the medium along a media transport path, and a controller assembly. The controller assembly includes a sensor device for generating a position signal and a processor for processing the position signal. The actuator is actuated in response to an actuation command from the controller assembly, which actuation command is derivable from a feedback component and a feedforward component. The feedback component is based on a position error. The processor is further arranged for determining a time dependent status parameter, which status parameter represents a status of the medium on the medium roller. The processor is further arranged for deriving an actuation command estimate based on the status parameter, and wherein the feedforward component includes the actuation command estimate.