Drive Axle Smoothing Filter Initialization for Stable Motion Control
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Solution Overview
Problem
Existing control methods for drive axles in conveyor systems, such as long-stator linear motors, face challenges in efficiently managing movement profiles with jerk limitations, especially when activating smoothing filters during ongoing movements, which can cause undesirable jumps and instability due to inadequate initialization.
Innovation Solution
A method that initializes the smoothing filter by assuming a constant function for the highest time derivative of the desired value over a past time interval, allowing the filter to be activated during movement without disrupting the drive axis, using a ring buffer to update and store target values, thereby reducing computational effort and ensuring continuous output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a smoothing filter is activated during ongoing movement without proper initialization, then the filter can be applied to limit jerk, but the drive axis experiences undesirable jumps and instability
Solution Approach 1:
The patent applies preliminary action by initializing the smoothing filter with a setpoint profile generated from the current movement phase before activation. The initialization process creates a historical setpoint sequence that matches the ongoing movement, ensuring continuous and stable operation when the filter is activated during motion rather than only at startup.
2Stability of the object's composition
If the smoothing filter is initialized with past setpoints, then continuous movement is maintained, but the computational effort increases significantly
Solution Approach 1:
The patent applies dynamics by making the initialization approach adaptive based on the operational context. The system dynamically selects between full initialization with complete setpoint history and simplified initialization based on current movement phase, optimizing the balance between movement continuity and computational effort for different operating conditions.
Solution Approach 2:
The patent changes the parameter of initialization depth based on operational needs. Instead of always using the full setpoint history, the system adjusts the initialization scope according to the current movement phase and operational context, reducing computational burden while maintaining sufficient movement continuity.
3Use of energy by stationary object
If simple motion profiles are generated without inherent jerk limitation, then computational power is conserved, but the drive axis experiences high jerk and increased load
Solution Approach 1:
The patent introduces the smoothing filter as an intermediary component between the simple motion profile generator and the drive axis. The filter acts as a mediator that processes the simple motion profiles and limits jerk output, thereby protecting the drive axis from high jerk loads while maintaining computational efficiency of the motion profile generation.
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 enables smooth and continuous movement even after activating the smoothing filter, limiting repeated time derivatives like jerk, and reduces the computational burden, allowing for stable control without negative effects on the drive axis or its components.
Implementation Method 1
a smoothing filter in the form of a mean value filter calculates the new setpoint as the mean value from the past setpoints that are one filter time in the past
Implementation Method 2
A moving magnetic field is generated by the drive coils, which interacts with the excitation magnets on the transport units in order to move the transport units
Data Source
Figure 1
Figure 2~3
Figure 4~8
AI summary
In order to activate a smoothing filter for a setpoint, with which the movement of a drive axis (A, Ai) of a drive unit (AE) can be controlled even during movement without negatively influencing the movement, it is provided that the smoothing filter (10) is initialized with a setpoint profile (Sinit), so that a current movement phase ((S0, S0, ..., S0(x))) is continuously continued and the further time derivative (S(x+1)) of the highest time derivative (S(x)) of the setpoint (S(t), S(k)) is limited.