Power Steering Controller Dead Zone Compensation
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Solution Overview
Problem
Existing vehicle power steering systems experience awkward steering feel due to dead zones between the steering wheel angle and actual wheel angle, particularly at curve entrances, which existing steering support devices fail to adequately address without introducing complex mechanisms or controls.
Innovation Solution
A power steering controller that includes a basic assist torque setting unit, a driving road shape recognizing unit, and an assist torque correction unit to offset steering torque characteristics based on the curvature radius and steering speed, reducing the assist torque's impact on the steering direction, thereby improving steering feel without additional complex mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the rigidity of the joint is improved and gear meshing backlash is reduced to eliminate dead zone effects, then steering precision is improved, but vibration and noise performance deteriorates
Solution Approach 1:
The patent replaces mechanical solutions (increasing joint rigidity, reducing backlash) with a control system solution. The power steering control device uses a controller to detect steering wheel angle and curvature radius, then dynamically adjusts assist torque to compensate for dead zone effects, achieving steering precision without mechanical modifications that would increase vibration and noise
Solution Approach 2:
The patent changes the parameter of assist torque dynamically based on steering conditions. By detecting steering wheel angle and curvature radius, the system adjusts assist torque magnitude and direction to compensate for dead zone effects, achieving precise steering control without altering mechanical parameters like joint rigidity or backlash
2Speed
If steering support control is added to suppress delay of additionally turning the steering wheel at curve entrances, then steering response is improved, but the dead zone effect causing awkward steering feel remains unresolved
Solution Approach 1:
The patent implements feedback control by detecting the steering wheel angle with a steering angle sensor and curvature radius with a curvature radius sensor, then using this information to dynamically adjust assist torque. This closed-loop feedback system simultaneously improves steering response and eliminates dead zone effects, resolving both steering response and steering feel issues
Solution Approach 2:
The patent performs preliminary action by detecting curvature radius in advance and pre-adjusting assist torque before the driver needs to correct steering. The controller calculates required assist torque based on predicted steering conditions, enabling smooth steering transitions without the awkward dead zone effect
3Ease of operation
If additional mechanisms or controls are introduced to address dead zone effects, then steering feel is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing power steering control device multi-functional by adding dead zone compensation capability to its standard assist torque function. The controller uses the same steering angle sensor and curvature radius sensor for both lane keep control and dead zone compensation, eliminating the need for additional dedicated mechanisms while improving steering feel
Solution Approach 2:
The patent merges dead zone compensation control with the existing power steering assist control into a unified control system. The controller simultaneously performs lane keep control and dead zone compensation by integrating the control algorithms, reducing overall system complexity compared to separate dedicated systems
Data Source
AI summary
A basic assist torque is set on the basis of the vehicle speed and the steering torque, and when the vehicle changes from a straight driving state to a curve driving state, a correction amount for the basic assist torque is calculated, which is to offset steering torque characteristic values which has been predetermined depending on a steering angle, in a direction opposite to the steering direction by correcting an absolute value of the basic assist torque to reduce its action on the steering direction depending at least upon the curvature radius of the driving road in front of the vehicle, and the basic assist torque is corrected with the basic assist torque correction amount and the controlled/corrected torque (assist torque) is output to a motor drive unit.