Rotary Shifter Sensor Assembly for Reliable Angular Position Detection
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Solution Overview
Problem
Shifters with rotatable actuation elements face unreliable detection of angular positions, leading to potentially dangerous situations due to misinterpretation, and adding fault detection mechanisms makes them complex and expensive.
Innovation Solution
A shifter with a sensor assembly comprising at least three binary sensors and a trigger device, where trigger elements are distributed to allow each angular position to be reliably detected, using a detent track and plunger for discrete positions, and a control unit for software-implemented automated return to park with reassignment of states, and fault detection to ensure accurate operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a shifter uses a rotatable actuation element without end positions (360° rotation), then the shifter allows software-implemented automatic return to park and flexible reassignment of angular positions to transmission states, but the detection of angular position becomes unreliable and may lead to misinterpretation
Solution Approach 1:
The trigger device is segmented into multiple trigger lines (at least three) with distributed trigger elements, where each binary sensor corresponds to one trigger line. This segmentation allows the system to detect angular position through multiple independent channels, improving reliability while maintaining the 360° rotation capability and flexible reassignment of positions to transmission states.
Solution Approach 2:
The control unit receives detection signals from multiple binary sensors and uses feedback logic to determine the current angular position of the actuation element. The control unit processes the combined information from all sensors to reliably identify the angular position even without mechanical end positions, enabling both reliable detection and flexible software-based position assignment.
2Reliability
If a shifter adds fault detection and reliable checks to ensure accurate transmission state selection, then the reliability of transmission control improves, but the device becomes increasingly complicated and expensive
Solution Approach 1:
The sensor assembly is segmented into multiple independent binary sensors that can be distributed on simple circuit boards or integrated into the actuation element. This segmentation allows for reliable fault detection through multiple sensors while keeping each individual sensor simple and cost-effective, avoiding the need for a single complex detection system.
Solution Approach 2:
The multiple binary sensors serve dual purposes: they provide redundant detection for reliability and fault detection, while also enabling the software-implemented automatic return to park feature and flexible reassignment of angular positions. This multi-functionality reduces the need for separate dedicated fault detection mechanisms, thereby limiting the increase in device complexity.
3Reliability
If a shifter uses multiple binary sensors with distributed trigger elements, then the reliability of angular position detection improves, but the manufacturing complexity and cost increase
Solution Approach 1:
The multiple binary sensors and their corresponding trigger lines are merged into an integrated sensor assembly where the sensors can be arranged on a common substrate or circuit board. The trigger elements are distributed on the actuation element in a pattern that corresponds to the sensor arrangement, allowing for standardized manufacturing processes and reducing assembly complexity despite the increased number of components.
Solution Approach 2:
The system uses binary sensors that detect the presence or absence of trigger elements through parameter changes (such as optical, magnetic, or capacitive fields) rather than requiring complex mechanical connections. This allows for easier manufacturing and integration of multiple sensors while maintaining reliability, as the detection mechanism remains simple and standardized across all sensor-trigger line pairs.
Data Source
AI summary
A shifter for controlling a transmission of a motor vehicle includes a rotatably mounted actuation element, a sensor assembly including a first element having a plurality of binary sensors and a second element having a trigger device. A control unit determines an angular position of the actuation element based on an input signal from the sensor assembly. The binary sensors and the trigger device are arranged such that each binary sensor corresponds to one trigger line comprising a plurality of trigger elements. The trigger elements are distributed along the trigger line such that at least one the binary sensors is able to detect a presence of a trigger element for each angular position of the actuation element. At least one trigger element from each trigger line together form a trigger pattern, and the trigger pattern is repeated at least twice on the trigger device to initiate a shift command.