Active Headrest Position Control for Predicted Rear Collisions
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Solution Overview
Problem
Conventional headrest control systems fail to effectively manage the position of the headrest during multiple predicted collisions, leading to insufficient protection and interference with the driver when collisions are avoided or when the headrest is moved unnecessarily.
Innovation Solution
A headrest control apparatus that includes a rear state detection device, collision determination device, headrest drive mechanism, motor, and head position detection device, which controls the headrest's longitudinal position by activating the motor in response to collision predictions, holding it in a forward position for a predetermined time, and then retracting it, with adaptive timing adjustments based on new collision predictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the headrest is moved forward to protect the occupant during a predicted collision, then the occupant protection function is improved, but the headrest interferes with the driver when the collision is avoided
Solution Approach 1:
The headrest is moved forward in advance before a collision occurs based on prediction from the rear state detection device and collision determination device. This preliminary action ensures protection is ready when needed while allowing time to reverse if the collision is avoided.
Solution Approach 2:
The headrest control portion dynamically adjusts the headrest position based on real-time collision risk assessment. The system continuously monitors rear vehicle state and modifies the headrest position accordingly - moving forward when collision is predicted, holding when collision is imminent, and reversing when collision is avoided.
2Device complexity
If the headrest is held in the forward position for a fixed hold time, then the control is simplified, but the headrest may fail to protect the occupant during consecutively predicted collisions
Solution Approach 1:
The collision determination device continuously monitors rear vehicle state and provides feedback to the headrest control portion. When a new collision is predicted during the hold period, the system receives feedback signaling renewed collision risk and immediately extends the hold time or reverses the headrest to maintain protection.
Solution Approach 2:
The system prepares for potential consecutive collisions by extending the hold time in advance when new collision risks are detected. This preliminary extension ensures the headrest remains in the protective forward position throughout multiple collision scenarios without requiring complex real-time adjustments.
3Object-affected harmful factors
If the headrest returns to the initial position immediately after moving forward, then the driver interference is minimized, but the occupant protection function is insufficient during the return motion
Solution Approach 1:
The headrest control portion initiates the backward drive in advance when the collision determination device determines that collision risk has sufficiently decreased. This timing ensures the headrest returns to the initial position before a potential collision occurs, eliminating driver interference while maintaining protection during the return motion.
Data Source
AI summary
A headrest control apparatus has a rear radar sensor, a PCS-ECU, a headrest drive mechanism that supports a headrest and drives the headrest relative to the vehicle in its longitudinal direction, a motor, a capacitance sensor, and a headrest control portion that controls the motor. The headrest control portion executes a forward drive control in which the headrest starts to be driven forward in response to a start-up signal from the PCS-ECU and the motor is stopped in response to the positional relation between the occupant's head and the headrest reaching a predetermined positional relation. After the forward drive control, the headrest control portion executes a hold control in which the motor is held in a stopped state for a predetermined hold time. After the hold control, the headrest control portion executes a backward drive control in which the headrest is driven backward.