Power Steering Motor Closed-Loop Circuit Braking Force
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Solution Overview
Problem
Conventional power steering systems experience a deterioration in steering feeling during transitions from power steering to manual steering due to abrupt disturbances and sudden motor stoppage, which cannot be sufficiently mitigated.
Innovation Solution
A power steering apparatus with a permanent magnet field-type motor and an abnormality monitoring unit that forms a closed-loop circuit to generate a braking force, preventing abrupt changes in steering force and maintaining a smooth transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switch unit is opened to shut off the inverter and motor from each other when an ON-malfunction occurs, then the closed-loop circuit is opened to transition from power steering to manual steering, but abrupt disturbances are directly transmitted to the driver causing deterioration in steering feeling
Solution Approach 1:
The patent introduces a damping mechanism as an intermediary element between the motor and the steering system. This damping mechanism absorbs and attenuates abrupt disturbances and vibrations before they are transmitted to the driver, thereby resolving the contradiction between ensuring safety during malfunction and preventing deterioration in steering feeling.
2Reliability
If the motor suddenly stops supplementing the steering force during transition, then the closed-loop circuit is opened for manual steering, but the steering force changes abruptly causing deterioration in steering feeling
Solution Approach 1:
The patent implements a damping mechanism that is activated in advance or simultaneously with the motor stoppage to cushion and smooth out the transition. This beforehand cushioning prevents abrupt changes in steering force by continuously damping vibrations and disturbances during the transition period, thereby maintaining steering feeling quality while ensuring transition safety.
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 braking force generated by the closed-loop circuit effectively suppresses abrupt changes in steering force, thereby preventing a deterioration in steering feeling during transitions from power steering to manual steering.
Implementation Method 1
a motor of a permanent magnet field type for supplementing the steering force
Implementation Method 2
the closed-loop circuit including the motor generates a braking force
Data Source
AI summary
Provided is a power steering apparatus capable of suppressing an abrupt change in steering force and preventing a deterioration in steering feeling even in the event of a transition from power steering to manual steering. The power steering apparatus includes a torque sensor, a motor of a permanent magnet field type, and a controller having a motor driving unit and an abnormality monitoring unit, for controlling the driving of the motor. The motor driving unit includes an inverter for driving the motor, and a drive signal generating unit for calculating a target current caused to flow through the motor and outputting a drive signal of the inverter based on the target current. The abnormality monitoring unit includes an abnormality processing unit for constituting a closed-loop circuit including the motor in stopping the driving of the motor.