Shift Range Control Device with Sensor Abnormality Detection

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Solution Overview

Problem

Conventional shift range control devices face challenges in accurately switching shift ranges due to sensor abnormalities, which can lead to incorrect target angle settings and potential damage to the shift range switching mechanism.

Innovation Solution

A shift range control device comprising a motor angle calculation unit, output shaft signal acquisition unit, abnormality determination unit, and drive control unit, which acquires motor and output shaft signals, determines sensor abnormalities, and adjusts target angles to ensure safe and accurate shift range switching, even in the presence of sensor faults.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the output shaft sensor is used to detect rotational position for target angle setting, then shift range switching accuracy is improved, but sensor abnormality can cause incorrect target angle settings leading to mechanism damage

Engineering Contradiction:

Improverotational position detection accuracyVSAvoidsystem reliability under sensor abnormality

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The control device determines whether the output shaft sensor is abnormal before setting the target rotation angle. By performing this preliminary check and preparing alternative target angles in advance, the system prevents incorrect target angle settings that could damage the shift range switching mechanism when sensor abnormalities occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system sets different target rotation angles based on sensor status: a first target angle when the sensor is normal, and a second target angle when the sensor is abnormal. This beforehand preparation of alternative solutions cushions against the harmful effects of sensor failure and ensures continuous safe operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If the system operates with sensor abnormalities, then limp-home performance is improved, but incorrect target angle setting can cause collisions and mechanism damage

Engineering Contradiction:

Improvelimp-home performanceVSAvoidcollision risk to mechanism

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system converts the harmful effect of sensor abnormality into a beneficial condition by detecting the abnormality and automatically selecting an appropriate second target angle. This allows the vehicle to maintain limp-home performance while preventing collisions and mechanism damage that would otherwise occur.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The control device continuously monitors sensor status and uses this feedback to determine the appropriate target rotation angle. When sensor abnormality is detected, the feedback mechanism triggers a switch to the second target angle setting, ensuring safe operation throughout the limp-home mode.

Inventive Principle:

Principle #23Feedback

3Device complexity

If conventional target angle setting is used without sensor abnormality detection, then device complexity is reduced, but shift range switching safety deteriorates

Engineering Contradiction:

Improvecontrol system complexityVSAvoidshift range switching safety

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control device performs multiple functions: it detects sensor abnormalities, determines appropriate target angles based on sensor status, and controls motor driving accordingly. By integrating these functions into a single control device, the system maintains relatively simple device architecture while significantly improving shift range switching safety.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11624438B2Shift range control device

Publication Date: 2023.04.11 DENSO CORP

AI summary

A motor angle calculation unit acquires from a motor rotation angle sensor a motor rotation angle signal corresponding to a rotational position of the motor, and calculates a motor angle based on the motor rotation angle signal. An output shaft signal acquisition unit acquires, from an output shaft sensor that detects a rotational position of an output shaft, an output shaft signal corresponding to the rotational position of an output shaft. An abnormality determination unit determines abnormality in the output shaft sensor. A target angle setting unit sets a target rotation angle corresponding to a target shift range. A drive control unit controls driving of the motor so that the motor angle becomes a target rotation angle. The target angle setting unit sets the target rotation angle to different values when the output shaft sensor is normal and when the output shaft sensor is abnormal.