Linear Motor Thrust Constant Derivation Using Multi-Condition Measurement
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Solution Overview
Problem
Existing linear motor technologies face challenges in deriving a thrust constant with sufficient precision due to friction resistance changes nonlinearly with velocity, affecting movement control accuracy.
Innovation Solution
A method and device that perform actual measurements under multiple conditions to derive both average and local thrust constants, quantifying friction resistance and interpolating precise thrust constants for each position, enhancing derivation precision and movement control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If actual measurement is performed at a fixed velocity to derive thrust constant, then the measurement process is simple, but the derivation precision is insufficient due to nonlinear friction resistance changes
Solution Approach 1:
The measurement process is segmented into multiple distinct measurement conditions (first measurement condition and second measurement condition). Each condition involves moving the moving body through the measurement zone at different velocities or acceleration patterns. By dividing the measurement into segments with different characteristics, the system captures friction resistance variations more comprehensively, thereby improving thrust constant derivation precision without requiring overly complex measurement setups.
Solution Approach 2:
The measurement approach transitions from a static fixed-velocity measurement to dynamic measurements where the moving body is accelerated and decelerated at different rates. The system varies the velocity profile and acceleration patterns across different measurement conditions to account for the nonlinear relationship between friction resistance and velocity. This dynamic measurement strategy enables more accurate thrust constant derivation by capturing friction characteristics under diverse operating conditions.
2Reliability
If friction resistance is not considered in thrust constant derivation, then the measurement process is simple, but the movement control accuracy deteriorates
Solution Approach 1:
The system incorporates friction resistance compensation through a feedback mechanism. During the thrust constant derivation process, the system measures the relationship between driving force and velocity under multiple conditions, identifies friction resistance characteristics, and uses this information to compensate for friction effects in the control algorithm. This feedback approach improves movement control accuracy by accounting for friction without requiring complex mechanical modifications to the linear motor system.
Solution Approach 2:
The system changes measurement parameters (velocity, acceleration, direction) to characterize friction resistance behavior. By performing measurements under different parameter conditions and analyzing how friction varies with these parameters, the system builds a friction model that can be applied during operation. This parameter-based approach enables accurate friction compensation through software algorithms rather than complex hardware solutions.
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 increases the precision of thrust constant derivation and movement control by accounting for friction resistance variations, leading to more accurate positional control and reduced errors in linear motor systems.
Implementation Method 1
a thrust which is generated between a coil with a current running therethrough and a magnet
Data Source
Figure 1~3
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Figure 6~7
AI summary
The present invention provides a method of deriving a thrust constant representing an occurrence rate of a thrust in relation to a current in a linear motor which is provided with a track member which includes a magnet extending in a movement direction, and a moving body which includes a coil mounted to the track member in a movable manner, the linear motor generating a thrust in the movement direction between the magnet and the coil by causing the current to flow in the coil, in which an average thrust constant which is an average thrust constant in a long movement zone on the track member is derived based on actual measurement, local thrust constants which are local thrust constants of a plurality of locations on the track member are derived based on each actual measurement, and the thrust constants of arbitrary positions on the track member are derived based on the average thrust constant and the local thrust constant of each location. Accordingly, it is possible to increase derivation precision of the thrust constant more than in the related art based on actual measurement under a plurality of actual measurement conditions.