Motor Control Device for Inkjet Printer Carriage Velocity Stabilization
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Solution Overview
Problem
DC motors in inkjet printers experience cyclic torque changes, leading to pulsated rotational velocity, causing unstable carriage driving and alternating thick and thin color regions during printing due to excessive overlap of cyclic signals in existing motor control methods.
Innovation Solution
A motor control device and method that generates a driving signal by multiplying or dividing an initial signal with a cyclic signal, synchronized with the motor's velocity to counteract cogging cycles, ensuring stable operation by minimizing the influence of torque changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a cyclic signal is overlapped with the driving signal to suppress cogging cycle, then the driving velocity becomes constant, but the ratio of cyclic signal occupying the output becomes excessive causing instability
Solution Approach 1:
The patent changes the parameter of signal combination from addition (overlap) to multiplication. By multiplying the driving signal by the cyclic signal, the system achieves velocity stabilization while controlling the cyclic signal's influence through the driving signal's magnitude, preventing excessive occupation ratio and maintaining control stability.
Solution Approach 2:
The patent introduces a multiplication operation as an intermediary between the driving signal and cyclic signal. This intermediary operation allows the cyclic signal to modulate the driving signal in a controlled manner, stabilizing velocity while preventing the cyclic signal from dominating the output.
2Speed
If the driving signal is lowered near the end of driving range to decrease velocity, then the carriage velocity is reduced, but the cyclic signal ratio becomes excessive causing large pulsation
Solution Approach 1:
The patent changes the signal combination method from addition to multiplication. When the driving signal is lowered near the end of the driving range, the multiplication operation ensures that the cyclic signal's absolute value remains proportional to the driving signal's magnitude, preventing excessive cyclic signal ratio and large pulsation while still achieving velocity reduction.
Data Source
AI summary
A motor control device includes: an operation amount setting unit that sets an operation amount of a motor for driving a driving target according to a predetermined driving signal; and a control unit that generates the driving signal. The control unit generates an initial driving signal such that a velocity of the driving target follows an external velocity command, generates a cyclic signal having a cycle according to an angular velocity of a motor shaft of the motor, and generates the driving signal by multiplying the initial driving signal and the cyclic signal, based on at least one of a position and a velocity of the driving target.