Dual Stepper Positioning Drive Tensioning Control
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Solution Overview
Problem
Existing positioning drives face challenges in achieving precise positioning due to elasticity, production tolerances, friction, and play in the kinematic transfer chain, leading to inaccuracies and dynamic issues such as oscillations and overshooting, especially in highly dynamic applications.
Innovation Solution
A positioning drive system utilizing two stepper motor units with a central control unit that applies kinematic and tensioning reference values to eliminate play by ensuring synchronized movement of all coupling inputs, achieving a tensioning state through load angle manipulation without direct motor current control, using stepper motors with identical types and operation in micro-step mode for high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If elastic preload elements are used to eliminate play in the kinematic transfer chain, then positioning precision is improved, but device complexity increases and additional actuators are required
Solution Approach 1:
The patent changes the control parameter from simple position control to combined position and tensioning control. By manipulating the load angle parameter of the stepper motors, the system creates a tensioning state that eliminates play without requiring additional mechanical preload elements or actuators.
Solution Approach 2:
The existing stepper motors are made to perform dual functions: position control and tensioning control. The same motors that drive the power take-off element also create the tensioning state through load angle manipulation, eliminating the need for separate actuators or preload mechanisms.
2Manufacturing precision
If two servomotors with field-oriented current regulation are used to apply preload moments, then positioning precision is improved, but device complexity and control system complexity increase
Solution Approach 1:
The patent replaces expensive servomotors with field-oriented current regulation with simpler stepper motors. The stepper motors achieve the same tensioning effect through load angle manipulation without requiring complex current control systems, thereby reducing device complexity while maintaining positioning precision.
3Manufacturing precision
If mechanical preload elements are used to eliminate play, then positioning precision is improved, but energy efficiency deteriorates due to continuous preload force
Solution Approach 1:
Instead of continuous preload force from mechanical elements, the system uses periodic or as-needed tensioning control through load angle manipulation. The tensioning state is created only when necessary to eliminate play during positioning operations, reducing continuous energy consumption while maintaining positioning precision.
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 solution effectively eliminates play and achieves precise positioning with high resolution and accuracy, reducing dynamic errors and enhancing the positioning drive's efficiency by utilizing the load angle to maintain a tensioning state, allowing for sub-step position changes and improved control of the power take-off element.
Implementation Method 1
two stepper motor units (21, 24) with a first stepper motor (23) and a second stepper motor (26)... each with a stator (23 S, 26 S) and a rotor (23 R, 26 R)... a load angle occurs in the two stepper motors (23, 26), which bring about a tensioning moment
Data Source
AI summary
A positioning drive has a first stepper drive unit having a first stepper drive controller and a first stepper motor, and a second stepper drive unit having a second stepper drive controller and a second stepper drive. The two stepper drives and the power take-off element are force-coupled and drive-coupled by a mechanical coupling unit. A central unit controls the two stepper drive controllers by a control signal, in each instance. The control signals predetermine the stator reference field angle and the rotor reference field angle set by the stepper drive controller. The central unit has an overriding regulator for the position of the power take-off element, and a subordinate regulator for setting a tensioning moment for each stepper motor. The tensioning moments occur by setting a load actual angle at the stepper drive.