Steering Device Auxiliary Control Unit Torque Transition
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Solution Overview
Problem
Existing steering systems with electric steering assistance face issues of high torque jumps and increased accident risk when switching to purely mechanical operation due to sudden shutdowns, leading to driver irritation and reduced flexibility and operational reliability.
Innovation Solution
A steering device with a main control unit for normal operation and an auxiliary control unit that takes over in error states, allowing independent operation and passive mode in normal conditions, minimizing computing effort and ensuring smooth transitions to emergency operation by controlling the electric motor's torque reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main control unit is switched off suddenly in a fault state to enable mechanical fallback operation, then steering safety is ensured through mechanical operation, but a large torque jump occurs on the steering handle causing driver irritation and increased accident risk
Solution Approach 1:
The auxiliary control unit is activated in advance before the main control unit is switched off. It gradually reduces the electric motor torque to zero over a predetermined time period, preparing the system for mechanical fallback operation while avoiding sudden torque changes that would cause driver irritation
Solution Approach 2:
The system implements a cushioning mechanism by using the auxiliary control unit to smoothly transition the torque from the electric motor to zero. This prevents the abrupt torque jump that would otherwise occur during the switch to mechanical operation, protecting the driver from irritation and potential accidents
2Reliability
If the auxiliary control unit is designed to monitor the main control unit and control the electric motor in fault states, then operational reliability is improved, but computational effort and system complexity significantly increase
Solution Approach 1:
The control functions are segmented into two independent control units: the main control unit for normal operation and the auxiliary control unit for fault states. Each unit has a specific, simplified responsibility, avoiding the need for a single complex control unit to handle all scenarios
Solution Approach 2:
The auxiliary control unit is extracted as a separate, independent component with dedicated fault-state handling capabilities. It contains only the essential functions needed for emergency operation, removing unnecessary complexity from the main control unit while ensuring operational reliability
3Productivity
If the auxiliary control unit operates in passive mode during normal operation, then computational effort is minimized and efficiency is optimized, but the system must ensure smooth transition to active mode in fault states
Solution Approach 1:
The auxiliary control unit is kept in a preliminarily activated state during normal operation, maintaining readiness to take over control functions. This preliminary preparation ensures that when a fault occurs, the transition to active mode is smooth and reliable without requiring complex activation sequences
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5
AI summary
The invention relates to a steering device, more particularly to the provision of electrical steering assistance, having at least one main control unit (10a-e), which is provided to control, in at least one normal operating state, operation of at least one electric motor (12a-e), and having at least one auxiliary control unit (14a-e), which is provided to control, in at least one faulty operating state in which a fault in and/or failure of the main control unit (10a-e) has occurred, operation of the electric motor (12a-e). According to the invention, the main control unit (10a-e) can be operated independently of the auxiliary control unit (14a-e) and the auxiliary control unit (14a-e) is set in the normal operating state to a passive operating mode.