Motor Control Apparatus for High-Speed Precision Positioning
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Solution Overview
Problem
Existing motor control systems face challenges in achieving high-speed and high-precision control, particularly in stopping a driven object at a target position due to limitations in controlling current degradation by counter-electromotive force and accuracy in feedback controls.
Innovation Solution
A motor control apparatus that includes a first control unit for estimating a current upper limit based on counter-electromotive force, a second control unit for precise positioning, and a switching unit that determines the appropriate control strategy based on calculated necessary and remaining displacement amounts, allowing for high-speed operation with precise stopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If feed-back control based on target profile is used to stop the driven object at a target position with high accuracy, then positioning precision is improved, but control speed is limited
Solution Approach 1:
The control process is divided into two distinct phases: a first control phase using bang-bang control for high-speed movement, and a second control phase using feed-back control for precise positioning. The switching unit transitions between these phases based on calculated displacement amounts, allowing the system to achieve both high speed and high precision by applying the appropriate control method at the appropriate time.
2Speed
If bang-bang control is used to drive the driven object at high speed, then control speed is improved, but positioning precision deteriorates
Solution Approach 1:
The control process is divided into two distinct phases: a first control phase using bang-bang control for high-speed movement, and a second control phase using feed-back control for precise positioning. The switching unit transitions between these phases based on calculated displacement amounts, allowing the system to achieve both high speed and high precision by applying the appropriate control method at the appropriate time.
3Manufacturing precision
If the limit value of control input is set based on saturation current adjusted by counter-electromotive force, then control accuracy is improved, but control complexity increases
Solution Approach 1:
The necessary amount for stop is calculated in advance based on the current speed and a predetermined control pattern before the stopping phase begins. This preliminary calculation allows the switching unit to determine the optimal transition point between control phases, enabling accurate positioning without requiring complex real-time adjustments during the stopping process.
Solution Approach 2:
The switching unit acts as an intermediary that coordinates between the first control unit (bang-bang control) and the second control unit (feed-back control). It uses the calculated necessary amount for stop and remaining displacement amount to determine when to switch between control modes, simplifying the overall control architecture by centralizing the switching logic.
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 the driven object to be stopped at the target position with high precision and speed by optimizing motor control through the combination of first and second control units, effectively managing current limits and displacement calculations.
Implementation Method 1
a motor 20 having a stator 21 and a rotor 22
Implementation Method 2
current degradation by counter-electromotive force
Data Source
AI summary
A motor control apparatus including a motor control unit and a signal output unit that outputs a signal corresponding to rotation of the motor to displace an object to be driven to a target stop position, the motor control unit includes: a first control unit that estimates a current upper limit and determines a first control input; a second control unit that determines a second control input and controls the motor to stop the object to be driven at the target stop position; a first calculation unit calculates a necessary amount for stop, a second calculation unit that calculates a remaining displacement amount, a switching unit, enable the first control unit or the second control unit to control the motor with switching; based on the necessary amount for stop and the remaining displacement amount.