Machine Tool Load Center-of-Gravity Estimation From Axis Torque
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Solution Overview
Problem
Current methods for determining the mass and center of gravity location of a load in a moving system, such as machine tools, are either manual, require additional measurement steps, or lack precision, especially for asymmetrical or anisotropic workpieces, leading to potential operator errors and imprecise positioning.
Innovation Solution
A method and system that utilize a support capable of rotation around multiple axes with electronically controlled drive units to determine total moments of inertia and holding torques, allowing for automated calculation of mass and center of gravity location without additional sensors, enabling precise adaptation in position control and compensation for eccentric or changing loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual determination of mass and center of gravity is used, then operator flexibility is maintained, but operator errors and imprecision occur
Solution Approach 1:
The system automatically determines mass and center of gravity using the existing multi-axis support and drive units already present in the machine tool. The control unit calculates these parameters from measured moments of inertia and holding torques without requiring manual measurement or external devices, making the system self-sufficient and eliminating operator error while maintaining simplicity.
Solution Approach 2:
The patent replaces manual mechanical measurement methods with an automated calculation system. The control unit computes mass and center of gravity from dynamically measured moments of inertia and holding torques obtained during normal operation, substituting human operators with automated computational methods that eliminate subjectivity and error.
2Measurement precision
If additional measurement steps are performed before clamping, then accurate mass and center of gravity data is obtained, but measurement time increases
Solution Approach 1:
The system performs mass and center of gravity determination as a preliminary automated step that integrates seamlessly into the existing workflow. By using the multi-axis support system already in place and calculating parameters from moments of inertia and holding torques during normal operation, the measurement occurs automatically before machining begins, eliminating the need for separate manual measurement steps while maintaining accuracy.
Solution Approach 2:
The patent combines the mass and center of gravity determination process with the existing multi-axis support system. The same support and drive units used for positioning workpieces are also utilized to measure moments of inertia and holding torques, merging the measurement function with the existing mechanical system rather than requiring separate dedicated measurement equipment.
3Ease of operation
If preset values are used for workpiece mass and position, then setup is simplified, but accuracy decreases for asymmetrical or anisotropic workpieces
Solution Approach 1:
The system dynamically determines actual mass and center of gravity parameters through measurement of moments of inertia and holding torques during operation, replacing static preset values with dynamically calculated parameters. This allows the system to adapt to the actual properties of each workpiece, whether symmetrical or asymmetrical, anisotropic or isotropic, ensuring high precision without complicating the setup process.
4Manufacturing precision
If costly adjusting procedures are performed in advance, then positioning precision is improved, but device complexity and cost increase
Solution Approach 1:
The control unit automatically compensates for positioning errors by calculating the actual center of gravity from measured moments of inertia and holding torques. This self-service approach eliminates the need for costly manual adjusting procedures or additional adjustment mechanisms, achieving high positioning precision through automated computational compensation rather than mechanical adjustment.
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 simplifies and enhances the determination of mass and center of gravity, reducing operator errors and achieving high manufacturing precision by automatically accounting for load characteristics during machining, allowing for real-time adjustments without re-measuring the workpiece.
Implementation Method 1
A total moment of inertia and a holding torque with regard to the first axis are determined in a loaded state. A total moment of inertia and a holding torque with regard to the second axis are also determined in the loaded state.
Implementation Method 2
The mass and the relative position of a workpiece in a holder or on a table of a moving system such as a swivel/rotation table of a machine tool have a decisive influence on the precision of a position control, particularly in the case of axes that are gravity-loaded.
Data Source
AI summary
The invention relates to a method for determining the mass and the center of gravity location of a load (10) of a moving system (12), particularly of a machine tool (14), which comprises a support (20) that is for accommodating the load (10) and is able to rotate around a first axis (16) and a second axis (18) as well as electronically controlled drive units (22, 24) for rotating the support (20) around the first axis (16) and around the second axis (18), whereina total moment of inertia and a holding torque with regard to the first axis (16) are determined in a loaded state;a total moment of inertia and a holding torque with regard to the second axis (18) are determined in the loaded state; andthe mass and the center of gravity location of the load (10) relative to the support (20) are determined based on the total moments of inertia and the holding torques with regard to the first axis (16) and second axis (18).The invention also relates to a moving system (12), which is equipped to determine the mass and the center of gravity location of a load (10) according to such a method.