METHOD FOR HYSTERESIS COMPENSATION IN AN ACTUATOR AND A SELECTOR FORK THAT IS ADJUSTABLY BY THIS ACTUATOR

Abstract

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.

Claims

1. 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.

2. The method according to claim 1, wherein the actuator, after the selector fork has been actuated into the particular shift position (xDgClu, xCoup, xDecoup), is mechanically released, namely controlled into the middle of the mechanical backlash (phiBL/2) under open-loop or closed-loop control.

3. The method according to claim 2, wherein the actuator is subject to open-loop or closed-loop control via a control unit which contains the state machine.

4. The method according to claim 2, wherein the shift position (xDgClu, xCoup, xDecoup) of the selector fork (1) and thus the position of the actuator (phiAtr, phiCoup, phiDecoup) is determined via at least one sensor, wherein a sensor signal from the sensor is processed in the state machine.

5. The method according to claim 1, wherein the selector fork is manufactured at least partially from plastic.

Description

DRAWINGS

[0023] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure.

[0024] FIG. 1 shows an isometric view of a selector fork and a sliding sleeve.

[0025] FIG. 2 shows a schematic illustration of a state machine.

[0026] FIG. 3 shows a table with target positions of a selector fork, the state correlations thereof and signs thereof stored in a state machine.

[0027] FIG. 4 shows a graph of the hysteresis of an actuator, wherein a position of an actuator is plotted on the x axis and the shift position of a selector fork or of a sliding sleeve is plotted on the y axis.

DETAILED DESCRIPTION OF THE INVENTION

[0028] The method according to the invention serves for hysteresis compensation in an actuator 3 and a selector fork 1 that guides a sliding sleeve 2 (FIG. 1) and is adjustable via the actuator 3. The selector fork 1 can be moved by means of the actuator 3 into two different shift positions, namely a first shift position xDecoup and a second shift position xCoup. The first shift position xDecoup of the selector fork 1 corresponds to a neutral position and the second shift position xCoup corresponds to a gear position. The actuator 3 can, to this end, be actuated into a first position phiDecoup, resulting in the selector fork 1 being moved into the first shift position xDecoup. Furthermore, the actuator 3 can be actuated into a second position phiCoup, resulting in the selector fork 1 being moved into the second shift position xCoup.

[0029] If the selector fork 1 is in a shift position xCoup, xDecoup, it is mechanically released via mechanical releasing of the actuator 3.

[0030] The actuator 3 is subject to open-loop or closed-loop control via a control unit (not illustrated in detail) which contains a state machine 4 (FIG. 2).

[0031] The particular state of the system, i.e. the particular shift position xCoup, xDecoup of the selector fork 1, is mapped by the state machine 4, which determines a correction of the position setting for the actuator 3 on account of its current and future state.

[0032] The starting point is a non-linear system in which the actuator 3 is intended to exactly position the selector fork 1 although it exhibits mechanical backlash phiBL (FIG. 3). In the graph in FIG. 4, a shift position of the selector fork xDgClu (y axis) is plotted versus a position of the actuator phiAtr (x axis).

[0033] The selector fork 1 is moved into the first shift position xDecoup via the actuation of the actuator 3 into the first position phiDecoup. The selector fork 1 is moved into the second shift position xCoup via the actuation of the actuator 3 into the second position phiCoup. The selector fork 1 has to be positioned exactly in the first shift position xDecoup, i.e. the neutral position, and in the second shift position xCoup, namely the gear position. Then, the actuator 3 is mechanically released, i.e. moved into the middle of the mechanical backlash phiBL. The particular position of the actuator 3 is described by the value phiAtr (FIG. 4; x axis). The target position phiAtrReq for the actuator can thus be formulated as follows (FIG. 3), phiAtrReq=phiTarget+signBL*phiBL/2 wherein phiTarget=phiDeCoup or phiCoup, as the first position phiDecoup or the second position phiCoup of the actuator 3, depending on the shifting request.

[0034] A sign signBL is generated by the state machine 4, and it can adopt the values +1, 0 and −1 (FIG. 3).

[0035] To describe the sequence of the method by way of example, the starting point is an uncoupled state, with the actuator 3 released (FIG. 2, “ForceFree Decoupled”). If a shifting request (FIG. 2, FIG. 3, step C1) is detected, the state machine 4 changes to the “Coupling” status and thus sets the desired position, namely phiTarget=phiCoup, and the associated sign, namely signBL=+1, (FIG. 3). Once the desired position of the actuator 3 has been set by closed-loop control, the actuator 3 and thus the selector fork 1 can start to be released (FIG. 2, FIG. 3, step C2) until phiTarget=phiCoup with the sign signBL=0 (FIG. 2, “ForceFree Coupled”). If a shifting request in the opening direction (FIG. 2, FIG. 3, step C3) is now detected, the state machine 4 changes to the “Decoupling” status and sets the desired position, namely phiTarget=phiDecoup, and the associated sign, namely signBL=−1. Once the target position has been reached, the actuator 3 and thus the selector fork 1 is released, namely until phiTarget=phiDecoup with the sign signBL=0 (FIG. 2, “ForceFree Decoupled”). It is possible to abort the shifting operation (FIG. 2, FIG. 3, steps C5 and C6) at any time. The backlash is always correctly passed through. If further system states are added, only the target position and the associated sing need to be added to the table. In this way, the hysteresis curve (FIG. 2) is always correctly passed through and the exact position of the selector fork 1 can be determined at any time.