Parallel Kinematic Load Simulation for High-Frequency Axle Testing
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Solution Overview
Problem
Current dynamic load simulation methods for vehicle axles are time-consuming and cost-intensive, requiring iterative learning processes and unable to apply hardware-in-the-loop simulations effectively due to insufficient control bandwidth and non-linear characteristics of actuators, leading to irreversible damage and limited frequency spectrum simulation.
Innovation Solution
A method utilizing a parallel kinematic excitation unit with a hexapod end effector, employing a control algorithm to directly adjust target pressures and compensate for non-linearities, allowing for real-time simulation of high-frequency signals and enabling hardware-in-the-loop simulations by measuring loads, comparing them to target signals, and determining actuator pressures for precise load application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If iterative learning processes are used to achieve high bandwidth and quality for target signal simulation, then simulation accuracy is improved, but time consumption and cost increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal control signals in a lookup table before actual testing. This allows the test rig to directly retrieve pre-computed control signals during operation, eliminating the need for time-consuming iterative learning processes while maintaining high simulation accuracy across different target signals.
Solution Approach 2:
The patent implements dynamics by creating a dynamic lookup table that can be adaptively updated based on operating conditions. The system transitions from static pre-computed tables to dynamically adjustable control signals that adapt to changing test requirements, reducing both time consumption and improving accuracy simultaneously.
2Manufacturing precision
If iterative learning processes are used to simulate target signals, then control quality is improved, but the risk of irreversible damage to test objects and systems increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating optimal control signals and storing them in lookup tables before actual testing begins. This allows the system to use pre-validated control signals that have been optimized offline, eliminating the need for iterative learning during actual tests and thereby preventing potential damage to test objects and equipment.
Solution Approach 2:
The patent implements beforehand cushioning by using pre-computed control signals that account for system non-linearities and constraints in advance. This preparatory optimization acts as a protective measure, ensuring that control signals are within safe operating limits before being applied to the test rig, thus preventing harmful effects.
3Device complexity
If traditional actuator systems with insufficient control bandwidth are used, then device complexity is reduced, but the ability to simulate high-frequency signals is limited
Solution Approach 1:
The patent introduces an intermediary element - a lookup table containing pre-computed control signals - that bridges the gap between simple actuators and high-frequency simulation requirements. The lookup table performs the complex computational work offline, allowing simple actuators to achieve high effective bandwidth by retrieving pre-optimized control signals rather than computing them in real-time.
Solution Approach 2:
The patent applies copying by creating a digital model (lookup table) that replicates the optimal control behavior. Instead of requiring complex physical actuators, the system copies the intelligent control decision-making into a lookup table that can be quickly queried, effectively transferring computational complexity from the physical actuator to the control software.
4Ease of operation
If invariant control parameters are used in test rigs, then ease of operation is improved, but adaptability to different target signals and aging conditions deteriorates
Solution Approach 1:
The patent implements dynamics by transitioning from static control parameters to dynamic lookup tables that can be adaptively updated. The system maintains ease of operation through automated table generation and retrieval, while simultaneously improving adaptability by allowing the lookup tables to be regenerated for different target signals and updated to compensate for aging effects.
Data Source
AI summary
The invention relates to a method for dynamic load simulation, wherein loads are specified by target signals and applied to a test object by a parallel kinematic excitation unit via an end effector, including the following operations:measuring loads at a contact point (200),comparing the measured loads with the target signals (300), anddetermining target pressures (400) for individual actuators of the parallel kinematic excitation unit for applying the target signals by use of a control algorithm (Fq,ref).This provides a method for dynamic load simulation that reduces the time and cost expenditure compared to previously known methods and at the same time enables hardware-in-the-loop simulations to be used.