Shift Range Control Apparatus Motor Angle Limiting
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Solution Overview
Problem
Conventional shift range control mechanisms are prone to erroneous target angle settings due to noise or abnormalities in output shaft sensor signals, leading to potential damage and improper shifting range switching.
Innovation Solution
A shift range control apparatus that includes a motor angle calculating unit, an output shaft signal acquiring unit, a target angle setting unit, and a driving control unit, which sets a target rotation angle based on a target shift range and output shaft signal, and adjusts it to a target limit value if the target angle is set further back in the rotation direction, thereby preventing damage and ensuring proper shifting range switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the target rotation angle is set based on the output shaft sensor signal, then the shifting range switching accuracy is improved, but the system becomes vulnerable to noise and sensor abnormalities causing erroneous angle settings
Solution Approach 1:
The control device applies preliminary anti-action by pre-establishing a limit value for the target rotation angle before actual switching occurs. When the calculated target angle exceeds this predetermined limit, the system proactively clamps it to the limit value, preventing erroneous large-angle movements caused by noise or sensor failures before they can cause damage.
Solution Approach 2:
The system implements feedback by continuously monitoring the target rotation angle calculation results and comparing them against the predetermined limit value. This closed-loop verification ensures that any abnormal target angles generated by sensor noise or failures are detected and corrected by being restricted to the safe limit value.
2Reliability
If the target rotation angle is restricted to a limit value, then the system reliability is improved by preventing damage, but the switching precision may be reduced when erroneous angles occur
Solution Approach 1:
The system applies partial action by selectively restricting the target rotation angle only when it exceeds the predetermined limit value. When the calculated angle is within normal ranges, the system maintains full switching precision without any restriction, thus avoiding unnecessary interference with accurate switching operations while still providing protection against abnormal conditions.
3Device complexity
If the target rotation angle is set without considering rotation direction, then the control simplicity is maintained, but the system cannot prevent backward rotation beyond the limit
Solution Approach 1:
The system applies dynamics by making the target rotation angle adaptive rather than fixed. The target angle dynamically adjusts based on the relationship between the calculated angle and the predetermined limit value, automatically clamping to the limit when exceeded. This dynamic adjustment mechanism provides robust protection against backward rotation while maintaining relatively simple control logic.
Data Source
AI summary
A shift range control apparatus controls a shift range switching system that switches shift ranges by controlling driving of a motor. This control apparatus calculates a motor angle based on a motor rotation angle signal, acquires an output shaft signal based on a rotation position of an output shaft from an output shaft sensor, sets a target rotation angle based on a target shift range and the output shaft signal, and controls driving of the motor such that the motor angle becomes the target rotation angle. The control apparatus sets the target rotation angle to a target limit value, in response to the target rotation angle that is set based on the output shaft signal being a value at which rotation occurs that is further toward a back side in a rotation direction than the target limit value that is set based on shift ranges before and after switching.