Electrical Actuator Friction Control in Nested Contact Systems
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Solution Overview
Problem
Existing control methods for electrical actuators in mechanical systems with multiple contacting surfaces struggle to accurately and stably compensate for friction, especially in complex architectures where nested friction zones complicate the determination of individual surface contributions.
Innovation Solution
A method involving the use of multiple LuGre models in parallel, combined with a stochastic optimization algorithm, to acquire data, determine model parameters, and create a compensation structure for effective friction modeling and stabilization, which is then integrated into the actuator's control relationship.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex friction models (de Leuven, GMS) are used to model nested friction zones, then modeling accuracy is improved, but control stability deteriorates
Solution Approach 1:
The patent segments the nested friction zones into multiple independent LuGre models, each modeling a specific contact interface (e.g., shaft-bushing, bushing-bearing). This segmentation allows accurate representation of each zone's friction characteristics while maintaining overall control stability through modular structure.
Solution Approach 2:
The patent changes the modeling parameters by using simplified LuGre model parameters for each nested zone rather than the complex parameters of de Leuven or GMS models. This parameter simplification maintains adequate modeling accuracy while ensuring control stability through the well-established LuGre framework.
2Measurement precision
If complex friction models are used to account for multiple contacting surfaces, then friction compensation accuracy is improved, but system complexity increases
Solution Approach 1:
The patent divides the complex friction system into multiple independent LuGre models, one for each nested contact zone. This segmentation provides accurate friction compensation for each interface while keeping the overall model structure manageable through modular organization.
Solution Approach 2:
The patent combines multiple simplified LuGre models to represent the overall nested friction system. This merging approach achieves comprehensive friction compensation accuracy equivalent to complex models while maintaining the simplicity and computational efficiency of individual LuGre models.
3Measurement precision
If individual friction contributions of nested surfaces are determined, then friction modeling precision is improved, but measurement and detection difficulty increases
Solution Approach 1:
The patent segments the total friction measurement into individual contributions from each nested contact zone by assigning separate LuGre models to each interface. This segmentation enables precise determination of individual friction contributions through the distinct parameters of each model without requiring direct measurement of each surface.
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 precise and stable control of electrical actuators by accurately modeling and compensating multiple friction zones, resulting in smooth and effective movement of movable elements.
Implementation Method 1
When two parts having friction surfaces in contact that rub against each other when the movable element moves
Implementation Method 2
the roughnesses are modeled in the form of spring blades in such a manner that the spring blades of one of the contacting surfaces interact with rigid blades of the other contacting surface
Data Source
AI summary
A method of controlling an electrical actuator of a mechanical system having a plurality of nested zones of contact, the method comprising the steps of:acquiring data about the mechanical system, which system includes a number of nested zones of contact;preparing a model of the system on the basis of said data and of a number of LuGre models put in parallel equal to the number of nested zones of contact, and determining parameters of the model and also a compensation structure for compensating friction in the nested zones of contact;including the compensation structure in a control relationship for the actuator A; andcontrolling the actuator by means of the control relationship.