PROCEDURE FOR CALIBRATION OF A GEARBOX AND CALCULATION UNIT

Description

[0001] The present invention relates to a method for calibrating a gearbox, a computing unit and a computer program for carrying it out, and a computer-readable data carrier. Background of the invention

[0002] Two-speed gearboxes can be used in mobile machinery. Due to the high torques that need to be transmitted, precise adjustment is desirable for proper function with minimal wear. In particular, after an ignition reset, a switching actuator driven by an electric motor, or its control unit, should be informed of the actuator's current mechanical position, since generally, one rotor angle of the electric motor corresponds to several positions of the switching actuator.

[0003] A method for calibrating a manual transmission according to the state of the art is disclosed in document DE 10 2008 000 641 A1. Disclosure of the invention

[0004] According to the invention, a method for calibrating a manual transmission according to claim 1, a computing unit according to claim 7, a computer program according to claim 8 and a computer-readable data carrier according to claim 9 are proposed.

[0005] Advantageous embodiments are the subject of the dependent claims and the following description.

[0006] The invention relates to a transmission with at least two gears, in which an actuator (shift actuator or transmission actuator) is movable within an actuator range between two end stops, wherein sub-ranges of the actuator range correspond to the gears. The invention employs a method of determining which gear of the transmission is engaged and, depending on the engaged gear, modifying a control variable of the actuator's drive such that the actuator comes to rest against an end stop enclosed within the sub-range corresponding to the engaged gear. When the actuator is at the end stop, the corresponding end value of the control variable is detected, and based on this detected end value, a correspondence between the values ​​of the control variable and the actuator positions is adjusted. This can be considered a partial calibration or rapid calibration.This type of calibration is advantageous because it requires no gear change, thus preventing additional wear and allowing for a quick calibration process. Furthermore, partial calibration can be performed independently of other drivetrain components, meaning the transmission doesn't have to wait for all drivetrain components to be released. Overall, this results in a faster return to service for the transmission.

[0007] A computing unit according to the invention, e.g. a control unit of a manual transmission or of a machine in which the manual transmission is installed, is, in particular in terms of programming, equipped to carry out the method according to the invention.

[0008] Implementing the inventive method in the form of a computer program or computer program product with program code for carrying out all process steps is also advantageous, as this incurs particularly low costs, especially if an executing control unit is already available for other tasks. Suitable data carriers for providing the computer program are, in particular, magnetic, optical, and electrical storage media, such as hard drives, flash memory, EEPROMs, DVDs, etc. Downloading a program via computer networks (Internet, intranet, etc.) is also possible.

[0009] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0010] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified, but also in other combinations or on their own, without leaving the scope of the present invention, which is defined by the following claims.

[0011] The invention is schematically illustrated in the drawing using exemplary embodiments and is described in detail below with reference to the drawing. Figure description Figure 1 schematically shows an arrangement with end stops and an actuator of a manual transmission, which is used to explain the relationship between an actuator area, end stops and gears. Figure 2 shows a flowchart according to a preferred embodiment. Detailed description of the drawing

[0012] Figure 1This outlines the relationship between an actuator range 2, end stops 4 and 6, and the gears of a manual transmission. The actuator 1 is movable between a first end stop 4 and a second end stop 6, which are separated by a specific distance. The distance between the end stops can be determined, for example, during a complete calibration. If the actuator is in the first sub-range 8 of actuator range 2, first gear is engaged. The first sub-range 8 includes the position designated as the first end position, in which the actuator contacts or rests against the first end stop 4. If the actuator is in the second sub-range 10 of actuator range 2, second gear is engaged. The second sub-range 10 includes the position designated as the second end position, in which the actuator contacts or rests against the second end stop 6.The first sub-area 8 includes a first target position 12, where the actuator should ideally be located when first gear is engaged. The second sub-area 10 includes a second target position 14, where the actuator 1 should ideally be located when second gear is engaged. Contrary to what is shown, the two sub-areas 8 and 10 can also be adjacent to each other.

[0013] Actuator 1 is driven or actuated by an electric drive (not shown), in particular an electromagnetic drive or electric motor. To set a desired position of the actuator, the electric drive is activated to achieve the desired position. However, this requires knowledge of the starting position and the relationship between the actuator movement and the drive movement. These parameters can be determined during actuator calibration, for example, by moving the actuator to its end stops, so that the current position can then be determined from there.

[0014] Furthermore, a processing unit 20 is shown, which serves to control the transmission. The processing unit 20 is specifically designed to control the actuator's drive (e.g., via control lines not shown). It may also be provided that the processing unit 20 acquires position data from a position sensor for the actuator or position data (e.g., angular position data or drive speed).

[0015] During full calibration, actuator 1 is moved so that it first reaches one of its end stops and then the other. The known distance between these stops (actuator movement) can be correlated with the drive movement (e.g., motor revolutions) so that the current actuator position can be determined. A full calibration thus also establishes a correlation between a change in the actuator's position and a change in the drive's position.

[0016] This full calibration includes shifting through both gears. However, it is advantageous here to perform only a partial calibration, in which only one of the end stops is reached and shifting is avoided. This procedure is demonstrated using the Figure 2 , which shows a flowchart according to a preferred embodiment, explains.

[0017] In preferred step 100, an (initial) complete calibration is performed as described above. This complete calibration is carried out, for example, immediately after completion of the transmission. The recorded end values ​​of the manipulated variable are stored, e.g., in a control unit configured to perform the procedure. Thus, an end value for the first end position and an end value for the second end position, as well as an (initial) correspondence between the actuator's position change and the drive's position change, are known or stored. During each subsequent complete calibration (see below), these stored values ​​are expediently replaced with current values.

[0018] The further process steps preferably take place during normal operation (e.g. at certain times or in certain time intervals) and / or when a machine in which the gearbox is installed is started.

[0019] Step 110 determines which gear is engaged. This can be done by evaluating a gear signal from a transmission sensor or a position signal from a position sensor that detects the position of the actuator or a component moved by it.

[0020] When first gear is engaged (e.g., the gear signal indicates that first gear is engaged, or the position signal indicates that the actuator is in the first sub-area 8), the drive is activated in step 120 until the actuator reaches the first end stop 4, and the corresponding value is set as the actuator's position. The direction in which the drive must move to move the actuator to the first end stop 4 is known, as the fundamental functional relationship between drive movement and actuator position is known. Therefore, no gear change occurs. Starting from this end stop 4, all further positions can be approached using the stored correspondence between the actuator's position change and the drive's position change.

[0021] In a preferred step 130, the first target position 12 is then approached. This occurs immediately after approaching the first stop, i.e., specifically without approaching the second end stop in the meantime.

[0022] Preferably, a partial calibration check (preferred steps 140 to 170) is performed at a later time, after shifting into the other gear, i.e., second gear, during normal operation (e.g., detectable via the gear signal and / or the position sensor). For this purpose, in step 140, the drive is activated until the actuator reaches the second end stop 6, and the corresponding position is determined from the position of the first end stop 4, the drive movement, and the stored correspondence. In step 150, it is checked whether there is an initial deviation (more precisely, the magnitude of the initial deviation) of the determined position from an expected position (i.e.,the position expected when the actuator moves from the first end stop over the known distance to the second end stop) is above a first threshold (the first threshold, as well as the second threshold mentioned below, can be specified as an absolute value or as a relative deviation).

[0023] If this is the case, a complete calibration is performed in step 160 (e.g., as described above). Preferably, the actuator is then moved to the second target position in step 170. If the first deviation does not exceed the first threshold, step 170 can be performed immediately after step 150.

[0024] Steps 140 to 170 are preferably only carried out when the gearbox is torque-free, i.e., when no torque is being transmitted by the gearbox, e.g., when the machine in which the gearbox is used is stationary.

[0025] If, in step 110, it is determined that second gear is engaged (e.g., the gear signal indicates that second gear is engaged, or the position signal indicates that the actuator is in the second sub-area 10), in step 180 the drive is activated until actuator 1 reaches the second end stop 6, and the corresponding value is set as the actuator's position. The direction in which the drive must move to move actuator 1 to the second end stop 6 is known, since the fundamental functional relationship between drive movement and actuator position is known. Therefore, no gear change occurs. Starting from this end stop 6, all further positions can be approached using the stored correspondence between the actuator's position change and the drive's position change.

[0026] In a preferred step 190, the second target position 14 is approached. This occurs immediately after approaching the second end stop, i.e., specifically without approaching the first end stop in the meantime.

[0027] Preferably, a partial calibration check (preferred steps 200 to 230) is performed later, after the system has shifted into the other gear, i.e., first gear, during normal operation (e.g., detectable via the gear signal and / or the position sensor). In step 200, the drive is activated until the actuator reaches the first end stop 4, and the corresponding position is determined from the position of the second end stop 6, the drive movement, and the stored correspondence. In step 210, it is checked whether a second deviation (more precisely, the magnitude of the second deviation) of the determined position from an expected position (i.e., the position expected when the actuator moves from the second end stop over the known distance to the first end stop) exceeds a second threshold (which may be equal to the first threshold).

[0028] If this is the case, a complete calibration is performed in step 220 (e.g., as described above). Preferably, the actuator is then moved to the first target position in step 230. If the second deviation does not exceed the second threshold, step 230 can be performed immediately after step 210.

[0029] Steps 200 to 230 are preferably only carried out when the gearbox is torque-free, i.e., when no torque is being transmitted by the gearbox, e.g., when the machine in which the gearbox is used is stationary.

Claims

1. A method for calibrating a gearbox with an electrically driven actuator (1), which has a first and a second gear, wherein the gearbox has a first and a second end stop (4, 6), between which an actuator area (2) extends, in which the actuator is movable, wherein the first gear is engaged when the actuator is in a first partial area (8), which includes the first end stop, of the actuator area, and the second gear is engaged when the actuator is in a second partial area (10), which includes the second end stop, of the actuator area, wherein an electric drive of the actuator is controlled to move the actuator in the actuator area (2); wherein the method comprises a partial calibration which includes the following steps: determining (110) which gear is engaged; if it has been determined that the first gear is engaged, controlling (120) the drive until the actuator is at the first end stop (4), and moving the actuator starting from the first end stop using a stored correspondence between a change in position of the actuator and a change in position of the drive; and if it has been determined that the second gear is engaged, controlling (160) the drive until the actuator is at the second end stop (6), and moving the actuator starting from the second end stop using the stored correspondence between a change in position of the actuator and a change in position of the drive; characterized in that if it has been determined in the partial calibration that the first gear is engaged, after the partial calibration, after the second gear has been engaged at a later point in time, the method further comprises the following steps: controlling (140) the drive until the actuator is at the second end stop (6) and determining a position of the second end stop (6); checking (150) whether a first deviation of the determined position of the second end stop (6) from a position of the second end stop (6) expected on the basis of the correspondence between a change in position of the actuator and a change in position of the drive is above a first threshold; if the first deviation is above the first threshold, performing a full calibration (160); wherein after the full calibration, the actuator is preferably moved to a second target position (14) in the second partial area (10) (170) or that if it has been determined in the partial calibration that the second gear is engaged, after the partial calibration, after the first gear has been engaged at a later point in time, the method further comprises the following steps: controlling (200) the drive until the actuator is at the first end stop (4) and detecting a corresponding value of the drive; checking (210) whether a second deviation of the detected value of the drive from a value of the drive expected on the basis of the correspondence between a change in position of the actuator and a change in position of the drive is above a second threshold; if the second deviation is above the second threshold, performing a full calibration (220); wherein after the full calibration, the actuator is preferably moved to a first target position (12) in the first partial area (8) (230).

2. The method according to claim 1, wherein an initial full calibration (100) is performed, in particular upon completion of the gearbox or installation of the gearbox in a machine.

3. The method according to any one of claims 1 or 2, wherein in the full calibration (100, 160, 220) the drive is controlled to move the actuator until it abuts one of the end stops (4, 6), and to detect a corresponding first value of the drive when the actuator abuts the one of the end stops, and subsequently to move it until it abuts the other of the end stops (4, 6), and to detect a corresponding first value of the drive; and wherein the stored correspondence between a change in position of the actuator and a change in position of the drive is redetermined or initially determined based on the first and the second value.

4. The method according to any one of the preceding claims, wherein the partial calibration further comprises the following steps: if it has been determined that the first gear is engaged, moving (130) the actuator to a first target position (12) in the first partial area (8), wherein the movement (130) of the actuator to the first target position (12) takes place immediately after approaching the first stop; or if it has been determined that the second gear is engaged, moving (190) the actuator to a second target position (14) in the second partial area (10), wherein the movement (190) of the actuator to the second target position (14) takes place immediately after approaching the second stop.

5. The method according to any one of the preceding claims, wherein, when determining (110) which gear is engaged, a signal from a position sensor or gear sensor is detected and evaluated.

6. The method according to any one of the preceding claims, wherein the steps of the method are carried out with the start of a machine in which the gearbox is installed, and / or wherein the steps of the method are carried out after the start during operation of the machine at specific times, in particular at regular times.

7. A control unit (20) for controlling a gearbox with an electrically driven actuator (1), which has a first and a second gear, wherein the gearbox has a first and a second end stop (4, 6), between which an actuator area (2) extends, in which the actuator is movable, wherein the first gear is engaged when the actuator is in a first partial area (8), which includes the first end stop, of the actuator area, and the second gear is engaged when the actuator is in a second partial area (10), which includes the second end stop, of the actuator area, wherein an electric drive of the actuator is controlled to move the actuator in the actuator area (2); wherein the control unit comprises a processor which is configured to carry out the steps of the method according to any one of the preceding claims.

8. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method according to any one of claims 1 to 6.

9. A computer-readable data carrier on which the computer program according to claim 8 is stored.