Vehicle Parking Control with Pre-Braking for Reliable Lock Engagement
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Solution Overview
Problem
Existing parking brake systems, such as described in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-530156 (JP 2009-530156 A), fail to reliably maintain a vehicle in a parked state when the driver leaves, potentially allowing the vehicle to move due to road inclinations, as the parking brake may not engage correctly.
Innovation Solution
A parking control device utilizing an electric motor as a driving power source, equipped with a controller that detects the driver's absence and vehicle speed, executing braking and parking mechanisms to ensure the vehicle remains stationary, even when the driver is away, by employing three-phase ON control and an electric brake mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the parking brake is operated automatically based on door locking detection, then the driver can leave the vehicle without manual intervention, but the vehicle may move before the door is locked and the parking brake engages
Solution Approach 1:
The system performs preliminary braking control before the parking brake engagement to reduce vehicle speed to a predetermined level. This preliminary action ensures that when the parking brake finally engages, the vehicle is moving slowly enough for reliable locking, thus resolving the timing issue between door locking and parking brake engagement.
Solution Approach 2:
The control device acts as an intermediary between the door locking detection and the parking brake operation. It introduces an intermediate step of speed reduction control, mediating the transition from vehicle movement to parked state, ensuring reliable parking brake engagement even when the driver is away from the vehicle.
2Reliability
If the vehicle speed is reduced by braking control before parking mechanism activation, then the parking mechanism can engage reliably, but the braking components experience excessive wear and load
Solution Approach 1:
The system applies braking control only partially - specifically when vehicle speed exceeds a predetermined threshold before parking brake engagement. This partial action is sufficient to reduce speed to a safe level for parking mechanism engagement, avoiding excessive or continuous braking that would cause unnecessary wear, thus balancing reliability with component durability.
3Reliability
If the parking brake is not operated during the time the driver leaves the seat, then the vehicle may move due to road inclination, but operating it immediately upon detection may cause the locking member to bounce back
Solution Approach 1:
The system performs preliminary speed reduction action before the parking brake engagement. By reducing vehicle speed in advance through braking control, the system ensures that when the parking brake finally engages, the rotation member is moving slowly enough to allow reliable locking without bouncing back, thus resolving the contradiction between timely engagement and reliable locking.
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 system effectively reduces vehicle speed and engages the parking mechanism to maintain the vehicle in a stopped state, preventing unintended movement and reducing wear on braking components by minimizing excessive loads.
Implementation Method 1
a vehicle equipped with an electric motor (2) as a driving power source
Implementation Method 2
an electric brake mechanism that is electrically controlled to generate a frictional force to stop rotation of a vehicle wheel
Implementation Method 3
a parking mechanism with a configuration that stops a rotation of the vehicle wheel by engaging a locking member with a rotation member
Data Source
AI summary
An unmanned detection unit detecting that the driver is away from the driver's seat, a vehicle speed detection unit detecting the vehicle speed of the vehicle, a vehicle speed determination unit determining whether the vehicle speed detected by the vehicle speed detection unit in a state where the driver is detected by the unmanned detection unit in a state where the driver is away from the driver's seat of the vehicle is equal to or lower than a predetermined vehicle speed, a braking control unit executing braking control for reducing the vehicle speed by determining that the vehicle speed exceeds the predetermined vehicle speed in a state where the driver is away from the driver's seat of the vehicle, and a parking control unit executing parking control for operating the parking mechanism when the vehicle speed becomes equal to or lower than the predetermined vehicle speed after executing braking control.