Electromagnetic Steering Damping for Fault-State Rack Oscillation
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Solution Overview
Problem
Rear wheel steering systems face uncontrollable oscillation during fault states such as microcontroller failure, battery power loss, or broken drive belts, necessitating a solution to maintain vehicle stability and control.
Innovation Solution
An electromagnetic damping system with a pinion gear, friction disk, and electromagnetic clutch that transitions between a spaced and contact position to control the steering rack's movement rate, providing calibrated friction during fault conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electromagnetic clutch is in the spaced position relative to the friction disk, then the steering rack can move freely for normal steering operation, but during fault states the system cannot provide damping control to prevent uncontrollable oscillation
Solution Approach 1:
The electromagnetic clutch acts as an intermediary device between the pinion shaft and friction disk. During normal operation, it maintains a spaced position allowing free movement. During fault states, it engages the friction disk to provide damping control, thus mediating between free motion and controlled damping without requiring permanent mechanical connection
Solution Approach 2:
The system changes the friction parameter dynamically by transitioning the electromagnetic clutch between spaced and contact positions. When spaced, friction is minimal allowing free steering. When contacted, friction increases to provide damping control during fault states, thus using parameter change to resolve the contradiction between free motion and controlled stability
2Reliability
If the electromagnetic clutch contacts the friction disk continuously, then damping control is always available, but normal steering operation is hindered by excessive friction
Solution Approach 1:
The electromagnetic clutch dynamically transitions between two states: spaced position during normal operation for free steering, and contact position during fault states for damping control. This dynamic switching resolves the contradiction by adapting the friction level to the operational state rather than maintaining a fixed configuration
Solution Approach 2:
The system employs periodic or conditional engagement of the electromagnetic clutch based on fault detection. The clutch engages only when needed (during fault states) and disengages during normal operation, using conditional periodic action to provide damping control without continuously hindering steering maneuverability
3Reliability
If a mechanical damping mechanism is added to the steering system, then fault state control is improved, but the device complexity and number of components increase
Solution Approach 1:
The electromagnetic clutch serves multiple functions: it acts as a damping control mechanism during fault states, while during normal operation it maintains a spaced position that does not interfere with steering. This multi-functionality resolves the contradiction by using a single component for both normal operation and fault state control rather than adding separate dedicated damping mechanisms
Solution Approach 2:
The patent replaces traditional mechanical damping mechanisms with an electromagnetic clutch that uses electromagnetic fields to control engagement with the friction disk. This substitution reduces mechanical complexity while achieving the same damping control function, as the electromagnetic actuation is more compact and controllable than purely mechanical spring-based or hydraulic damping systems
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
The system stabilizes the vehicle by dampening the steering rack's movement, allowing wheels to return to the center position and maintain stability during electrical and mechanical failures, enhancing safety in rear wheel steering applications.
Implementation Method 1
the coil generates an electromagnetic force that overcomes the spring force to attract the armature plate
Implementation Method 2
the friction disk is engaged by the armature plate to dampen a rotational speed of the pinion shaft
Data Source
AI summary
An electromagnetic damping system for a steering system includes a pinion gear having a pinion shaft and engaged with a steering rack. The electromagnetic damping system also includes a friction disk operatively coupled to the pinion shaft. The electromagnetic damping system further includes an electromagnetic clutch located adjacent the friction disk, the electromagnetic clutch disposed in a spaced position relative to the friction disk in a first condition of the electromagnetic clutch, the electromagnetic clutch disposed in a contact position relative to the friction disk in a second condition of the electromagnetic clutch to damp the rate of movement of the steering rack.