Motor Control Device Using Segmented Bang-Bang and Feedback Control
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Solution Overview
Problem
Existing motor control devices face challenges in achieving high-speed and high-precision control of driving objects, particularly in stopping at target positions and accelerating to target speeds, due to limitations in bang-bang control and feedback control methods.
Innovation Solution
A motor control device that employs a dual-control approach, using a first control unit for initial high-speed driving based on estimated current upper limit values and a second control unit for precise positioning using a two-degree-of-freedom control system with feedback and feedforward control, to switch control inputs smoothly and maintain precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If bang-bang control is used to drive the motor at maximum capacity, then the driving speed is improved, but the stopping precision at the target position deteriorates
Solution Approach 1:
The control process is divided into two distinct phases: a first control phase using bang-bang control for high-speed driving, and a second control phase using feedback control for precise positioning. This segmentation allows each control method to operate in its optimal performance range without compromising the other.
Solution Approach 2:
The control method dynamically switches between bang-bang control and feedback control based on the driving phase. The system transitions from maximum capacity driving to precision control, adapting the control strategy to the current operational requirements to achieve both high speed and high precision.
2Manufacturing precision
If feedback control based on target profile is used to achieve high precision, then the positioning accuracy is improved, but the driving speed deteriorates
Solution Approach 1:
The control process is divided into two distinct phases: a first control phase using bang-bang control for high-speed driving, and a second control phase using feedback control for precise positioning. This segmentation allows each control method to operate in its optimal performance range without compromising the other.
Solution Approach 2:
The system performs preliminary high-speed driving using bang-bang control to cover most of the distance quickly, then transitions to feedback control only for the final positioning phase. This preliminary action approach allows the system to achieve high overall speed while maintaining high precision for the critical positioning task.
3Manufacturing precision
If the control method is switched from first control unit to second control unit, then the control precision is improved, but control discontinuity may occur
Solution Approach 1:
The second control unit employs feedback control that continuously monitors the actual motor position and adjusts the control input accordingly. This feedback mechanism ensures smooth transition and eliminates discontinuity when switching from the first control unit, maintaining control stability while achieving high precision.
Solution Approach 2:
The control switching mechanism acts as an intermediary that coordinates the transition between the first and second control units. It ensures that the switch occurs at the optimal moment and that the control parameters are smoothly adjusted, preventing any discontinuity in the control signal to the motor.
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
Enables driving objects to be positioned or accelerated with high precision and speed, reducing control discontinuity and stabilizing motor control, thereby improving the quality of operations such as sheet conveying in printers.
Implementation Method 1
a current upper limit value estimation section that estimates a current upper limit value, which is an upper limit value of a current to be input to the motor, on the basis of a rotation speed of the motor taking into consideration a current decrease caused by back electromotive force
Data Source
AI summary
A motor control device includes: a motor control unit; and a signal output unit, the motor control unit includes: a first control unit configured to estimate a current upper limit value on the basis of the rotation speed of the motor and a current decrease caused by back electromotive force, the first control unit configured to determine a control input corresponding to the estimated current upper limit value, and a second control unit configured to determine a control input to be applied to the motor on the basis of an operation amount of the motor and a target value of the operation amount to control the motor, and in the early period of driving of the motor, the motor is controlled by the first control unit, and in the late period of driving of the motor, the motor is controlled by the second control unit.