DC Motor Control Apparatus with Dual Current Detection Systems
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Solution Overview
Problem
Existing control techniques for DC motors in 3D measuring devices face accuracy issues due to the limitations of current detection sensors, which struggle with both high and low current measurements, leading to deteriorated control performance, especially when the motor requires large currents and operates at low speeds or accelerations.
Innovation Solution
A control apparatus and method that employs two current detection systems: one without amplification for high-speed or high-acceleration conditions and another with amplification for low-speed or low-acceleration conditions, using a common current detection sensor to switch between them based on moving speed or acceleration thresholds, allowing for accurate control by combining signals from both systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a current detection sensor capable of measuring large current values is used, then the motor can operate at high power, but the detection accuracy for small current values deteriorates
Solution Approach 1:
The patent divides the current detection function into two separate detection systems: a first current detection system for detecting large current values and a second current detection system for detecting small current values. Each system is optimized for its specific range, with the second system including an amplifier to enhance sensitivity for low-current conditions. This segmentation allows the motor control to maintain both high power capability and precise low-current detection accuracy.
2Device complexity
If a single current detection sensor is used for both high and low current measurements, then the device complexity is reduced, but the control performance deteriorates in the small current range
Solution Approach 1:
The patent implements a dynamic switching mechanism that automatically selects which current detection system to use based on the motor's operating conditions. The control unit switches between the first and second current detection systems depending on whether the motor is operating in high-power or low-power modes. This dynamic adaptation ensures optimal control performance across the entire operating range without requiring a permanently complex dual-system configuration.
3Measurement precision
If feedback control is implemented for DC motor, then the control precision is improved, but the complexity of control system increases
Solution Approach 1:
The patent designs the dual current detection system where both detection paths ultimately feed into the same feedback control mechanism. The first and second current detection systems are not completely separate control loops but rather complementary detection paths that share the control unit and control objectives. This multi-functional design provides precise control across different operating conditions while avoiding the full complexity of two independent control systems.
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
This approach enhances the accuracy of motor control, particularly at low speeds or when the motor is stationary, preventing undulations and overflow issues, thereby improving the precision of 3D shape measurement by ensuring consistent and accurate probe movement.
Implementation Method 1
the second current detection system includes an amplifier
Data Source
AI summary
A control apparatus having high control performance is provided. A control apparatus according to an aspect of the present invention is a control apparatus that controls a DC motor, including a first current detection system that detects a current value of the DC motor, a second current detection system that detects a current value of the DC motor, and a control unit that controls the DC motor based on a signal indicating a current value input from the first or second current detection system, in which the second current detection system includes an amplifier.