Steering System Averaging Redundant Control Paths
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Solution Overview
Problem
In electromechanical steering systems with a master/master concept, discrepancies in input variables lead to opposing correcting torques or forces, causing excessive energy consumption and reducing the availability and service life of components due to thermal loading and control deviations.
Innovation Solution
A method and device that average the correcting variables from multiple control paths to generate a unified set correcting variable, preventing opposing actions by processing discrepancies at the digital level, and incorporating feedback control with integrator components to reduce windup effects and optimize controller dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple redundant control paths with equal rights are used in a master/master concept, then reliability is improved through redundancy, but control deviations with differing algebraic signs accumulate causing opposing correcting torques
Solution Approach 1:
The patent implements feedback control in each control path that includes an integrator component. The integrator accumulates control deviations over time, but the feedback mechanism ensures that opposing deviations with differing algebraic signs do not accumulate indefinitely. Instead, the feedback loop continuously adjusts the control variables to minimize the difference between actual and desired steering positions, preventing the accumulation of harmful opposing torques while maintaining redundant control paths for reliability.
2Measurement precision
If feedback control with integrator components is implemented in each control path, then positioning precision is improved, but control deviations accumulate resulting in differently directed correcting torques
Solution Approach 1:
The feedback control with integrator components achieves precise positioning by continuously adjusting control variables based on the difference between desired and actual positions. However, the patent addresses the accumulation problem by implementing the integrator within a closed feedback loop that prevents unbounded accumulation. The feedback mechanism detects when opposing correcting torques are generated and adjusts the control variables accordingly, maintaining positioning precision while preventing harmful torque accumulation.
3Speed
If correcting variables from multiple control paths are directly applied without averaging, then response speed is improved, but energy consumption increases due to opposing actions
Solution Approach 1:
The patent merges the correcting variables from multiple redundant control paths by applying an averaging operation. Instead of directly applying correcting variables from each control path separately (which would cause opposing actions and energy waste), the system combines them through averaging to generate a unified correcting variable. This approach maintains the responsive nature of individual control paths while eliminating energy-consuming opposing actions, as the averaged value represents a consensus among all control paths.
Data Source
AI summary
A method for operating a steering system includes providing an electromechanical steering assistance having several redundant control paths. Each control path includes a control unit, a power unit and a winding circuit of a servomotor. A correcting-variable unit is provided in each control unit in order to make a correcting variable available, depending on input variables. The correcting variables of all of the correcting-variable units are averaged. A set correcting variable is made available by each control unit, depending on the averaged correcting variable. A device for operating a steering system and a steering system for steering wheels of a motor vehicle, are also provided.