Steering Motor Control for Automated Parking
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Solution Overview
Problem
Conventional automated parking systems require a steering motor with a large rating to perform stationary steering, which results in a heavy, power-hungry motor that consumes excessive electric power and has durability issues.
Innovation Solution
A vehicle control device that uses external environment sensors to generate a movement path allowing the vehicle to initiate traveling without full steering at the starting position, utilizing a steering motor with a small rating by applying a steering axial force less than the full steering force, thereby avoiding stationary steering and reducing the load on the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If stationary steering (full steering during vehicle stoppage) is performed at the starting position of parking, then the vehicle can be parked in a U-shaped parking space with minimum turning radius, but the steering motor requires a large rating resulting in increased weight and power consumption
Solution Approach 1:
The patent applies dynamics by making the steering axial force variable rather than constant. The steering axial force is dynamically adjusted based on vehicle speed: at low speeds (below threshold speed Vth) the steering axial force is limited to prevent excessive load, while at higher speeds the full steering capability is available. This dynamic adjustment allows the steering motor to have a smaller rating while still achieving the required parking maneuver.
Solution Approach 2:
The patent changes the parameter of steering axial force from a fixed full steering force to a variable force that depends on vehicle speed. By introducing a threshold speed Vth and adjusting the steering axial force Fs accordingly (Fs ≤ Fmax when Vs ≤ Vth, and Fs can reach Ffull when Vs > Vth), the system achieves automated parking with a smaller steering motor rating.
2Productivity
If stationary steering (full steering during vehicle stoppage) is performed at the starting position of parking, then the vehicle can complete garaging in one forward and one rearward movement, but the steering motor consumes a large amount of electric power
Solution Approach 1:
The patent applies dynamics by making the steering axial force variable rather than constant. The steering axial force is dynamically adjusted based on vehicle speed: at low speeds (below threshold speed Vth) the steering axial force is limited to prevent excessive load, while at higher speeds the full steering capability is available. This dynamic adjustment allows the steering motor to have a smaller rating while still achieving the required parking maneuver.
Solution Approach 2:
The patent changes the parameter of steering axial force from a fixed full steering force to a variable force that depends on vehicle speed. By introducing a threshold speed Vth and adjusting the steering axial force Fs accordingly (Fs ≤ Fmax when Vs ≤ Vth, and Fs can reach Ffull when Vs > Vth), the system achieves automated parking with a smaller steering motor rating.
3Ease of operation
If a steering motor with a large rating is used to enable full steering during vehicle stoppage, then stationary steering can be performed, but the motor becomes large and heavy
Solution Approach 1:
The patent applies dynamics by making the steering axial force variable rather than constant. The steering axial force is dynamically adjusted based on vehicle speed: at low speeds (below threshold speed Vth) the steering axial force is limited to prevent excessive load, while at higher speeds the full steering capability is available. This dynamic adjustment allows the steering motor to have a smaller rating while still achieving the required parking maneuver.
Solution Approach 2:
The patent changes the parameter of steering axial force from a fixed full steering force to a variable force that depends on vehicle speed. By introducing a threshold speed Vth and adjusting the steering axial force Fs accordingly (Fs ≤ Fmax when Vs ≤ Vth, and Fs can reach Ffull when Vs > Vth), the system achieves automated parking with a smaller steering motor rating.
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
Enables automated parking with a smaller, more efficient steering motor, reducing power consumption and preventing overheating, allowing for agile and rapid parking without deteriorating the motor.
Implementation Method 1
the steering motor generates a driving force based on a steering instruction from the travel control unit and applies a steering axial force to a rack shaft to thereby cause vehicle wheels to be steered
Data Source
AI summary
A steering motor generates a driving force based on a steering instruction from a travel control unit and applies a steering axial force to a rack shaft to thereby cause vehicle wheels to be steered. An action planning unit, through the travel control unit, initiates traveling at a starting position of parking on a movement path by suppressing the steering axial force to be less than a maximum driving force of the steering motor.