Shift Range Control Apparatus Sensor Abnormality Handling
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Solution Overview
Problem
Existing shift range control systems face challenges in accurately controlling a motor's shift range when the rotation angle sensor becomes abnormal, leading to motor vibration and difficulty in achieving precise positioning.
Innovation Solution
A shift range control apparatus that includes an abnormality determination section and an abnormal-time controller, which allows for motor control without using the rotation angle sensor's detection value by switching the energization phase every energization phase switching period, with a current reduction period during which the duty is less than 100% in at least part of the energization duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotation angle sensor is used for motor control, then precise positioning can be achieved under normal conditions, but the system becomes unreliable when the sensor becomes abnormal
Solution Approach 1:
The system changes control parameters dynamically based on sensor status. When the rotation angle sensor is normal, the system uses sensor feedback for precise positioning control. When the sensor becomes abnormal, the system switches to open-loop control with predetermined energization patterns, changing the control mode parameter to maintain operational reliability
Solution Approach 2:
The system prepares alternative control strategies in advance for sensor failure scenarios. By pre-programming abnormal-time control patterns and energization sequences, the system cushions against the harmful effects of sensor failure, ensuring continuous operational reliability without requiring real-time diagnostic complexity
2Reliability
If open-loop control is used when the rotation angle sensor is abnormal, then the system can continue operating, but motor vibration occurs due to lack of feedback
Solution Approach 1:
The system applies periodic energization to the motor phases in a predetermined sequence when operating in abnormal mode. By systematically cycling through phase energization patterns, the motor generates sufficient vibration to overcome static friction and advance the rotor, maintaining operational continuity without requiring sensor feedback
Solution Approach 2:
The system skips the feedback control step that would normally prevent vibration and instead uses predetermined open-loop energization patterns to rush through the control cycle. This allows the motor to advance the rotor position through forced energization sequences, maintaining operational continuity despite the harmful vibration effect
3Measurement precision
If the energization phase is switched frequently to prevent vibration, then motor positioning can be maintained, but energy consumption increases
Solution Approach 1:
The system applies different energization strategies to different motor phases based on local requirements. When sensor feedback is unavailable, the system selectively energizes specific phases in predetermined patterns rather than continuously energizing all phases, achieving positioning accuracy while reducing overall energy consumption through localized phase-specific control
Data Source
AI summary
The present disclosure may provide a shift range control apparatus that controls on-off operations of switching elements in a driver circuit, drives a motor, and switches a shift range. The shift range control apparatus may be configured to determine an abnormality of a rotation angle sensor detecting a rotation angle of the motor, to control a drive of the motor using a detection value, and to execute a control which switches an energization phase every energization phase switching period without using the detection value of the rotation angle sensor in response to that the rotation angle sensor is abnormal.