Selector Fork Position Control With Hysteresis Compensation
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Solution Overview
Problem
Existing methods for positioning a selector fork via an actuator face challenges due to hysteresis, which complicates precise positioning and leads to wear over the component's service life, especially when using materials like plastic for the sliding shoes to achieve self-lubricating properties.
Innovation Solution
A method utilizing a state machine for hysteresis compensation in the actuator, allowing for precise positioning of the selector fork by correcting mechanical backlash between the actuator and the selector fork, using a position-controlled actuator and sensors like Hall sensors, and enabling open-loop or closed-loop control to maintain accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position-controlled actuator is used to move the selector fork, then positioning capability is provided, but hysteresis and mechanical backlash prevent precise positioning
Solution Approach 1:
The patent implements feedback control by continuously monitoring the actuator position and comparing it with the target position. The control unit processes this feedback information and adjusts the actuator commands to compensate for hysteresis and mechanical backlash, ensuring the selector fork reaches the precise target position despite these inherent system imperfections.
Solution Approach 2:
The patent changes the control parameters by introducing compensation values for hysteresis and backlash. The control unit dynamically adjusts these parameters based on the current state and direction of movement, modifying the actuator commands to account for the non-linear behavior and mechanical clearances in the system.
2Duration of action of stationary object
If sliding shoes are made from plastic or brass for self-lubricating properties, then wear resistance is improved, but positioning precision deteriorates due to compliance
Solution Approach 1:
The feedback control system monitors the actual position of the selector fork and compensates for positioning errors caused by the compliance of plastic or brass sliding shoes. The control unit adjusts the actuator commands based on this feedback, maintaining positioning precision despite the material compliance.
3Ease of manufacture
If mechanical backlash between actuator and selector fork is present, then ease of assembly is improved, but positioning accuracy worsens
Solution Approach 1:
The patent applies preliminary action by pre-compensating for mechanical backlash in the control algorithm. Before commanding the actuator to move to a target position, the control unit calculates and applies a compensation value that accounts for the mechanical clearances, ensuring the selector fork reaches the correct position despite the backlash.
Solution Approach 2:
The feedback control system detects positioning errors caused by mechanical backlash and continuously adjusts the actuator commands to compensate for these clearances, maintaining positioning accuracy while allowing for easy assembly with mechanical tolerances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for precise and flexible positioning of the selector fork, reducing wear and maintaining positioning accuracy while accommodating component tolerances, thus providing a robust solution for systems with backlash.
Implementation Method 1
Actuators generally exhibit hysteresis during their sequence of movements. This means that the actuator moves from a first state into a second state for example when a control signal is applied. If the control signal is set back to 'zero ', the actuator no longer returns fully into the first state, however.
Implementation Method 2
the position of the actuator, in the event of a shift request into the neutral position or into the gear position, is corrected on the basis of stored mechanical backlash between the actuator and the selector fork
Implementation Method 3
sensors like Hall sensors
Data Source
AI summary
A method for hysteresis compensation in an actuator and a selector fork that is adjustable by this actuator and guides a sliding sleeve, by means of a state machine, wherein the selector fork is moved by means of the actuator from a first shift position (xDecoup), namely a neutral position, into at least one second shift position (xCoup), namely a gear position, and vice versa, wherein the position of the actuator (phiAtr, phiCoup, phiDecoup), in the event of a shift request into the neutral position (xDecoup) or into the gear position (xCoup), is corrected on the basis of stored mechanical backlash (phiBL) between the actuator and the selector fork and of a sign (+1, 0, −1) generated by the state machine and associated with the particular shift request.