Vehicle Motor Control Device for Accurate Entrapment Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor control devices struggle to accurately detect positional displacement interference, such as entrapment of occupants' bodies or objects, especially during motor speed control changes like acceleration, deceleration, and constant speed operations, due to erroneous frictional resistance detection and reduced precision in speed control.
Innovation Solution
A motor control device with a main control portion that actuates the motor in acceleration, deceleration, and constant speed modes, and a displacement interference detection portion using actual and ideal rotation speeds to differentiate between frictional resistance and entrapment, employing pulse width modulation and reference differences to enhance detection precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the motor rotation speed is gradually increased or decreased during operation, then the seat movement becomes smoother and impact noise is reduced, but the precision of entrapment detection decreases due to pulse cycle variations
Solution Approach 1:
The patent applies dynamics by making the detection threshold dynamic rather than fixed. The threshold is adjusted based on the motor's operation phase (acceleration, constant speed, deceleration) and the direction of rotation. This allows the system to accommodate natural pulse cycle variations during speed transitions while still detecting actual entrapment events, thereby resolving the contradiction between smooth operation and detection precision.
Solution Approach 2:
The patent changes the parameter of detection threshold based on operating conditions. By setting different thresholds for acceleration, constant speed, and deceleration phases, and for forward/reverse directions, the system adapts to the varying pulse cycle characteristics during speed control, maintaining high detection precision without sacrificing smooth operation.
2Loss of time
If the motor starts with steady rotation speed, then the response time is reduced, but the seat may be suddenly moved or excessive load is applied to the motor
Solution Approach 1:
The patent implements periodic action through staged acceleration where the motor goes through multiple speed phases (initial acceleration, constant speed, second acceleration) rather than a single continuous acceleration. This periodic approach allows the system to balance quick response with controlled load application, preventing excessive force while maintaining acceptable start time.
3Ease of operation
If the motor is controlled to gradually increase or decrease rotation speed, then smooth operation is achieved, but it becomes difficult to distinguish between speed reduction due to control and entrapment of objects
Solution Approach 1:
The system dynamically adjusts detection thresholds based on the current operation phase (acceleration, constant speed, deceleration) and rotation direction. During acceleration and deceleration phases, higher thresholds are used to accommodate natural speed variations, while during constant speed phases, lower thresholds enable sensitive entrapment detection. This dynamic adaptation resolves the difficulty of distinguishing between controlled speed changes and entrapment events.
Solution Approach 2:
The system performs preliminary classification of the motor's operation phase before conducting entrapment detection. By determining whether the motor is in acceleration, constant speed, or deceleration phase, and whether it is rotating forward or in reverse, the system can pre-set appropriate detection thresholds, enabling accurate differentiation between normal speed control and actual entrapment conditions.
Data Source
Figure 1
Figure 2A~2B
Figure 3~5
AI summary
A motor control device, which includes a main control portion (1) configured to actuate a motor (30), which displaces a driven object (20, 61, 62) between a first position and a second position in an acceleration control mode in which a rotation speed of the motor (30) gradually increases, in a deceleration control mode in which the rotation speed of the motor (30) gradually decreases, and in a constant speed control mode in which the rotation speed of the motor (30) is maintained at a constant level, and a displacement interference detection portion (2) detecting that the displacement of the driven object (20, 61, 62) is interfered using an actual rotation speed (V), which is the actual rotation speed of the motor (30), and an ideal rotation speed (A) of the motor (30), on which a control result by the main control portion (1) including a feedback control is reflected.