Steering Device Torque Distribution and Friction Detection
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Solution Overview
Problem
Existing steer-by-wire steering systems face challenges in effectively controlling steerable wheels, requiring coordinated operation of multiple motors and lacking efficient methods to detect and mitigate anomalous friction increases in ball screw mechanisms, which can lead to reduced motion accuracy and increased wear.
Innovation Solution
A steering device with two motors and corresponding controllers that calculate and distribute torque commands using a changeable distribution ratio, allowing individual control of each motor to optimize steering and detect anomalous friction through current monitoring, thereby improving steering precision and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two motors are used to steer the steerable wheels, then the steering capability is improved, but the control complexity increases
Solution Approach 1:
The control system is segmented into a master controller that calculates total torque requirements and individual motor controllers that execute specific torque distributions. This segmentation allows complex two-motor control to be broken down into manageable sub-tasks, reducing overall control complexity while maintaining enhanced steering capability
Solution Approach 2:
The distribution ratio between the two motors is made dynamically adjustable rather than fixed. The system can change the torque distribution ratio based on operating conditions, motor status, and steering requirements, providing adaptability while simplifying control through automated dynamic adjustment
2Ease of operation
If a fixed torque distribution ratio is used between two motors, then the control is simplified, but the motion accuracy deteriorates
Solution Approach 1:
The torque distribution ratio is transformed from a static fixed value to a dynamic variable that can be adjusted in real-time based on steering angle, vehicle speed, and motor performance characteristics. This dynamic adjustment maintains control simplicity through automated algorithms while significantly improving motion accuracy by optimizing torque distribution for each operating condition
Solution Approach 2:
The system changes the distribution ratio parameter dynamically based on operating conditions. By adjusting this key parameter according to steering requirements and motor status, the system achieves both simplified control (through automated parameter adjustment) and improved motion accuracy (through optimized torque distribution)
3Duration of action of moving object
If the ball screw mechanism operates continuously, then the steering function is maintained, but friction increases and wear accelerates
Solution Approach 1:
The system implements feedback monitoring of motor current to detect anomalous friction increases in the ball screw mechanism. By continuously monitoring current consumption and comparing it against expected values, the system can detect friction anomalies and respond by adjusting torque distribution or alerting operators, thereby managing wear while maintaining continuous operation
Solution Approach 2:
The control system automatically detects and responds to friction anomalies without external intervention. Through self-monitoring of motor current and automatic adjustment of torque distribution, the system serves itself by mitigating wear effects and maintaining optimal operation, reducing the need for manual maintenance while enabling continuous operation
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 solution enhances steering precision by optimizing motor control and detects anomalous friction, leading to improved motion accuracy and extended component lifespan.
Implementation Method 1
two motors each configured to generate a drive force that steers a steerable wheel
Implementation Method 2
Rotation of the two motors is converted into linear motion of the steering rod by ball screw mechanisms including the ball nuts
Data Source
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AI summary
A steering device includes two motors each configured to generate a drive force that steers a steerable wheel of a vehicle and two controllers respectively corresponding to the two motors, each of the two controllers being configured to individually control a corresponding one of the motors. One of the two controllers is a first controller, and the other one of the two controllers is a second controller. The first controller is configured to calculate a command value corresponding to a total torque that should be generated in the two motors. The command value is divided into individual command values using a changeable distribution ratio set for each of the motors, the individual command values respectively corresponding to the motors. The two controllers are configured to respectively supply the motors with current corresponding to the individual command values.