Transmission Controller Rotation Direction Detection
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Solution Overview
Problem
Current transmission controllers face challenges in detecting changes in the direction of rotation of rotatable components using non-direction sensitive rotational speed sensors, leading to longer shifting times and increased wear, as they cannot discern the direction of rotation, which is crucial for efficient gear shifting and preventing damage during engagement.
Innovation Solution
A method that determines the change in direction of rotation by analyzing the duration of a continuous time interval where the rotational speed is below a predetermined value, detecting a change if the interval is shorter than a set duration, allowing for cost-effective detection using non-direction sensitive speed data from sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If unidirectional speed sensors are used to reduce cost, then device complexity and cost are reduced, but the ability to detect direction of rotation is lost
Solution Approach 1:
The patent uses the transmission controller as an intermediary that processes speed data from unidirectional sensors and infers rotation direction changes by analyzing speed transitions and gear state information. The controller mediates between the limited sensor data and the required directional information for shift control.
Solution Approach 2:
The patent replaces the need for bidirectional mechanical sensors with a computational approach using unidirectional sensor data combined with gear state logic. The system substitutes direct mechanical direction detection with algorithmic inference based on speed changes and known gear relationships.
2Reliability
If the transmission shifts through a neutral state to ensure known initial conditions, then reliability of shift engagement is improved, but shifting time increases
Solution Approach 1:
The system performs preliminary detection of rotation direction changes using the inferred directional information from speed data analysis. This allows the controller to prepare for direct shifts in advance, knowing the current rotation state, rather than always returning to neutral first.
Solution Approach 2:
The patent implements dynamic shift strategy that adapts based on detected rotation direction. When direction changes are detected, the system can execute direct shifts appropriate to the new direction without rigidly following the neutral-state protocol, making the shifting process more flexible and efficient.
3Reliability
If engagement is slowed down to prevent damage during shifts, then reliability is improved, but productivity decreases
Solution Approach 1:
The system uses feedback from continuous speed monitoring and direction change detection to dynamically adjust engagement timing. The controller receives feedback on rotation state and uses this information to optimize engagement speed and timing, preventing damage while maintaining efficient shifting rates.
Data Source
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AI summary
The invention relates to a method of detecting a change in the direction of rotation of a rotatable shaft (5) based on non-direction sensitive rotational speed data, the method comprising the steps: • determining a speed (17) of a rotatable shaft (5) of a vehicle transmission (3) based on non-direction sensitive speed data received from a non-direction sensitive rotational speed sensor (7), wherein the speed (17) of the rotatable shaft (5) is the absolute value of the rotational speed of the rotatable shaft (5); • determining, based on the speed (17) of the rotatable shaft (5), if the duration of a first continuous time interval (20) during which the speed (17) of the rotatable shaft (5) is continually smaller than a first predetermined speed value (18) is shorter than a predetermined duration (24); and • detecting that a change in the direction of rotation of the rotatable shaft (5) has occurred during the first continuous time interval (20) if the duration of the first continuous time interval (20) is shorter than the predetermined duration (24). The invention further relates to a controller (8) for carrying out the method and to a driveline (100; 200) including the controller (8). The invention allows to determine a change in direction although the sensor as such is not direction sensitive. This is based on the insight that decelerating to a speed value below a threshold and subsequently accelerating again to a value which is above this threshold corresponds to a change in direction if this process occurs within a short time period.