Drive Axle Motion Profile Control Without a Downstream Jerk Filter
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Solution Overview
Problem
Existing drive axle regulation methods face challenges in efficiently limiting jerk and eliminating the need for jerk filters, particularly in applications like long stator linear motors where computing power is limited.
Innovation Solution
The method involves creating a movement profile consisting of a starting and a target movement profile, where the target movement profile is derived using an acceleration profile with acceleration changes limited by a maximum jerk, ensuring a jerk-limited movement without the need for a jerk filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a jerk filter is used to limit acceleration changes, then the movement becomes smoother and mechanical loads are reduced, but computing power is consumed and dead time is introduced
Solution Approach 1:
The movement profile is pre-calculated with jerk-limited acceleration changes before execution. By planning the acceleration profile in advance with maximum jerk constraints, the system avoids the need for real-time jerk filtering during movement execution, thereby reducing computational load and eliminating dead time while ensuring smooth movement.
Solution Approach 2:
The jerk limitation function is extracted from the real-time control loop and integrated into the offline movement profile generation. This separates the jerk limiting computation from the real-time control execution, allowing the movement profile to be pre-computed with jerk constraints while the real-time controller only needs to follow the pre-established profile.
2Strength
If a jerk filter is applied to limit acceleration changes, then mechanical loads are reduced, but dead time is introduced in the control system
Solution Approach 1:
The acceleration profile is pre-calculated with jerk constraints applied before movement execution. This preliminary planning ensures that acceleration changes never exceed the maximum jerk limit, eliminating the need for real-time jerk filtering that would introduce dead time, while still achieving mechanical load reduction through smooth acceleration transitions.
3Measurement precision
If complex jerk filtering algorithms are used, then acceleration changes are precisely limited, but computing power is excessively consumed
Solution Approach 1:
The jerk-limited movement profile is generated in advance using simple iterative algorithms that calculate acceleration values step-by-step, ensuring maximum jerk constraints are met. This pre-computation approach achieves precise acceleration control without requiring complex real-time algorithms, significantly reducing computational power consumption during actual movement execution.
Solution Approach 2:
The movement profile is segmented into discrete regulation time steps with individually calculated acceleration values. Each acceleration value is computed based on simple iterative procedures that check jerk constraints, dividing the complex control problem into manageable segments that require minimal computational resources.
Data Source
AI summary
Disclosed is a method to determine a jerk-limited movement profile without the use of a downstream jerk filter. A movement profile consists of a starting movement profile and a target movement profile, wherein the starting movement profile starts at the starting movement phase and transitions into the target movement profile. The target movement profile is determined with an acceleration profile over a plurality of control time steps, wherein an acceleration change in each control time step maximally corresponds to a predefined maximum jerk, such that the acceleration profile of the target movement profile is provided as a step function. The step function is created while maintaining the predefined movement limits such that the area below the step function corresponds to a speed change between the beginning speed of the beginning movement phase and the target speed of the target movement phase.