Clutch system

Abstract

A system for controlling a clutch for controlling transmission of torque around a shaft to a vehicle, the system being provided with: an action member capable of rotating around the shaft; a motor that engages with the action member in a drivable manner and provides the action member with a rotational motion around the shaft; a conversion mechanism that engages with the action member in a drivable manner and converts the rotational motion around the shaft into an axial motion; a clutch member that is for forming the clutch, engages with the conversion mechanism in a drivable manner to be driven by the axial motion, and is axially movable from a first position for disconnecting the clutch to a third position for connecting the clutch through a second position in a reciprocating manner; and a controller that reads the angle of rotation of the motor to compare the same with a reference value and thus determines which of the first position, second position, and third position the clutch member is located at.

Description

[Technical Field]

[0001] The following disclosure relates to a system for controlling a clutch, and more particularly to a clutch system that can determine the position of a clutch member by utilizing the fact that the rotation angle of a motor reflects the position of the clutch member. [Background technology]

[0002] Rotating machinery used in vehicles often utilizes clutches to control its function. For example, a so-called lock-up differential incorporates a dog clutch. Normally, the dog clutch is disengaged, allowing differential movement between the output shafts. When the dog clutch is engaged by an external actuator, the differential is locked.

[0003] Even when the actuator is activated, the clutch may fail to engage under rare conditions, such as when the clutch teeth are not in a suitable position for meshing. Furthermore, even when the actuator is reversed, the clutch teeth may temporarily stick together due to factors such as the viscosity or magnetization of the lubricating oil, hindering disengagement. In other words, switching the actuator on and off does not always correspond to clutch engagement or disengagement. To prevent unexpected movements in rotating machinery, an additional device is often needed to detect whether the clutch is engaged or not.

[0004] Patent documents 1 to 3 disclose related technologies. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Patent Application Publication WO2018 / 109874A1 [Patent Document 2] Japanese Patent Application Publication No. 2004-208460 [Patent Document 3] International Patent Application Publication WO2018 / 118912A1 [Overview of the Initiative]

[0006] Unlike friction clutches, meshing clutches, such as dog clutches, do not slip between clutch members, reliably transmit torque when engaged, and do not lose energy when disengaged. On the other hand, noise, vibration, and harshness (often referred to as NVH, or NVH) often occur during the transition between engaging and disengaging due to interference between the dog teeth. How to control NVH to improve vehicle comfort remains an ongoing challenge in automotive technology.

[0007] The apparatus disclosed below was created in view of providing a clutch system that can better handle transition states without the need for additional special equipment.

[0008] According to one perspective, vehicles Cars in axis Rotation axis The system for controlling the clutch that controls the transmission of surrounding torque is the aforementioned rotate An action member rotatable around an axis, and the action member is drivenly coupled to the action member. rotate A motor that provides rotational motion around an axis, and the action member which is driven by the rotate The system comprises: a conversion mechanism that converts rotational motion around an axis into axial motion; a clutch member constituting the clutch, which is driven by the axial motion and coupled to the conversion mechanism, and is movable bidirectionally in the axial direction from a first position where the clutch is disengaged, through a second position, to a third position where the clutch is engaged; and a controller that reads the rotation angle of the motor and compares it with a reference value to determine whether the clutch member is in the first, second, or third position. The clutch member is equipped with dog teeth that mesh with an opposing member, and the clutch constitutes a dog clutch, and the second position is the position in which the dog teeth interfere with the opposing member. . [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram of a vehicle including the clutch control system. [Figure 2] Figure 2 is a partially exploded perspective view of a differential equipped with a clutch system. [Figure 3] Figure 3 is a cross-sectional elevation view of a differential equipped with a clutch system, taken along line III-III of Figure 2. [Figure 4] Figure 4 is a cross-sectional elevation view of a clutch system equipped with a conversion mechanism using a thread or spiral orbit. [Figure 5A] Figure 5A is a cross-sectional view of a schematic clutch, showing a disengaged state. [Figure 5B] Figure 5B is a cross-sectional view of a schematic clutch, showing an engaged state. [Figure 5C] Figure 5C is a cross-sectional view of a schematic clutch, showing a transitional state where the clutch teeth cannot mesh with each other. [Figure 5D] Figure 5D is a cross-sectional view of a schematic clutch, showing a transitional state where the tip surfaces of the teeth are facing the bottom of the teeth and the clutch teeth can mesh with each other. [Figure 6] Figure 6 is a graph schematically showing the relationship between the rotation angle of the rotor and the position of the thrust member. [Figure 7] Figure 7 is a schematic waveform diagram explaining the phase difference between current and voltage, showing the influence of the position of the rotor relative to the stator on the phase difference. [Figure 8] Figure 8 is a flowchart for determining the position of the clutch member based on the rotation angle. [Figure 9] Figure 9 is a flowchart for controlling the current applied to the motor according to the determined position of the clutch member. [Figure 10] Figure 10 is a flowchart showing a control flow including additional functions.

Embodiments for Carrying Out the Invention

[0010] Several exemplary embodiments will be described below with reference to the accompanying drawings. In the following description and the appended claims, unless otherwise specified, the axis means the central axis of the clutch, which usually coincides with the rotation axis of the power transmission device. It should be particularly noted that the drawings are not necessarily shown to an exact scale, and thus the mutual dimensional relationships are not limited to those shown.

[0011] The clutch system disclosed below can preferably be combined with a rotating machine constituting a vehicle to form a power transmission device, and in particular, it can be used for the purpose of connecting and disconnecting the clutch from the outside of the rotating machine to control its function. When the clutch is connected, the torque for driving the vehicle is transmitted through the clutch and is cut off when disconnected.

[0012] Referring to FIG. 1, the vehicle 100 includes an engine or a motor 61, and the torque generated by the engine or the motor 61 is transmitted to the differential 3 through the transmission 63, the transfer 65, and the propeller shaft 67 and is distributed to the rear axle 43 (in the case of a FR vehicle). Alternatively, there are cases where the transfer 35 also distributes torque to the front axle 41 (4WD vehicle), or cases where torque is distributed only from the transmission 63 to the front axle 41 through the front differential (FF vehicle). The differential 3 often incorporates a dog clutch 10 to control its operation, and this is driven by an appropriate actuator 1 placed outside the case 15.

[0013] The clutch system can be used to control the dog clutch 10. Figures 2 to 4 show examples of combination with a so-called lock-up differential, but it can also be combined with a so-called free-running differential. Of course, the applications are not limited to these. Based on this disclosure, the clutch system can be used in a wide range of rotating machines that include dog clutches, such as transmissions, power transfer units (PTUs), or coupling devices. The clutch is, for example, a so-called dog clutch with dog teeth, but other types such as claw clutches, and more generally, clutches that transmit torque by meshing rather than friction, would generally be usable.

[0014] For example, referring mainly to Figure 1 along with Figure 2, the solenoid 31 is electrically connected to an external electrical circuit 81 via a cable 37. Alternatively, the electrical circuit 81 may be partially or entirely built into the actuator 1, or it may be built into one of the ECUs as described later. A vehicle typically has multiple programmable electronic control units (ECUs) to electronically control its various parts. Each ECU includes a storage device for storing commands and data, and a microcontroller that can read these from the storage device and execute commands. Multiple ECUs communicate or share information with each other, for example, via a so-called controller area network (CAN).

[0015] One of the ECUs, the ECU 85, is electrically connected to the electrical circuit 81 and controls its function. Alternatively, the electrical circuit 81 is built into the ECU 85 and operates under its control. The electrical circuit 81 is further connected to the power supply 83 and, under the control of the ECU 85, supplies and disconnects power to the solenoid 31. The power supplied to the solenoid 31 can be DC, AC, pulsating, or pulsed, depending on the driving principle of the actuator 1.

[0016] Referring mainly to Figure 3 in combination with Figure 2, the differential 3 is a rotating body with an internal clutch 10 that is capable of rotating T around axis X. The differential 3 has a differential gear assembly 21 coupled to its case 15, and the differential gear assembly 21 has side gears 23 and 25, which are each coupled to the axle. In other words, the differential gear assembly 21 acts as a mediator that distributes the torque received by the case 15 to the side gears 23 and 25 while allowing differential action. Figure 3 illustrates a bevel gear type, but of course other types such as face gear type or planetary gear type may also be used.

[0017] In this example, the clutch member 11, which can transmit torque from the case 15, is movable in the axial direction, and the side gear 23 has clutch teeth and can be connected to the clutch member 11. The combination of the clutch member 11 and the clutch teeth constitutes the clutch 10. When the actuator 1 drives the clutch member 11 and the clutch 10 is engaged, the side gear 23 temporarily becomes one with the case 15 and transmits torque. At this time, the other side gear 25 can no longer differentially operate with respect to the side gear 23, so the differential 3 enters a so-called differential lock state where it has lost its differential action. When the actuator 1 disengages the clutch 10, the differential 3 differentially distributes the torque received by the case 15 to both axles.

[0018] The actuator 1 generally comprises a motor 5 that generates rotational motion R around axis X, and a conversion mechanism 7 that converts the rotational motion R into linear motion along axis X. The entire actuator 1 is coaxial with a rotating machine such as a differential 3, particularly its boss portion 19, and is also positioned, for example, in close proximity to or in contact with one end face of the rotating machine.

[0019] As illustrated in Figure 2, the motor 5, or as illustrated in Figure 3, the conversion mechanism 7, may be housed in the housing 14, and the housing 14 is prevented from rotating by engaging with the carrier on the vehicle body side. The rotation prevention can be achieved with a relatively simple structure; for example, as illustrated in Figure 2, it would be sufficient to engage a tab 55 fixed to the outer circumference of the housing 14 with the carrier. Of course, the housing 14 may also have some structure that engages directly without using a tab, and the object of engagement may be an element other than the carrier.

[0020] Referring to Figure 3 or Figure 4 in combination with Figure 2, the motor 5 generally comprises a solenoid 31 that generates magnetic flux in response to the application of power, a stator 33 that guides the magnetic flux, and a rotor 35 that generates rotational motion R around axis X due to the received magnetic flux. The stator 33, together with the solenoid 31, is fixed in place relative to the housing 14 around axis X and preferably also fixed in the axial direction.

[0021] The rotor 35 is made of a magnetic material to be driven by magnetic flux. To receive the magnetic flux guided from the stator 33, the rotor 35 is positioned slightly away from and opposite the stator 33 in the direction of axis X. As can be easily seen from the figures, the rotor 35 can be a hollow shaft, positioned coaxially with the case 15 and rotatable around its boss portion 19. In such an example, the rotor 35 can perform rotational motion R around axis X.

[0022] Alternatively, the rotor 35 may be on a different shaft from the case 15. In that case, the rotor 35 may not be hollow but have a solid gear shaft extending from it, and such gear shaft may mesh with the conversion mechanism 7 and drive it.

[0023] The examples shown in Figures 3 and 4 are all examples of axial gap motors, in which the rotor and stator are aligned axially and the magnetic flux is drawn out in a direction parallel to the axis. Of course, instead of an axial gap motor, a so-called radial gap motor can be used, in which the rotor is coaxial with the stator and is positioned radially inward or outward in close proximity. Furthermore, other suitable types of motors can be used.

[0024] As already explained, the solenoid 31 is connected to an external electrical circuit 81 via a cable 37. The electrical circuit 81 generates an alternating current or pulsed current with a phase difference and inputs it to each coil of the solenoid, thereby generating rotational motion R in the rotor 35. The direction of the rotational motion R can be controlled by the direction of the phase difference, meaning that the motor 5 can generate rotational motion R in both forward and reverse directions. A switching element can be used to generate the alternating current or pulsed current. For example, a semiconductor element such as an insulated-gate bipolar transistor (IGBT) can be used as the switching element, but it is not necessarily limited to this. Furthermore, although the above explanation relates to a so-called induction motor, various other forms such as synchronous, permanent magnet, commutator, and DC motors can be used instead.

[0025] The conversion mechanism 7 is driven by the rotor 35 and converts its rotational motion R into linear motion, which is then output to the thrust member 41. For this conversion, for example, a cam mechanism, a ball cam mechanism, a screw mechanism, or a roller screw mechanism can be used. Figure 2 shows an example using a cam mechanism, in which the thrust member 41 is ring-shaped and has a cam surface 41c that is inclined in the circumferential direction on the surface facing the rotor 35. Correspondingly, the rotor 35 has a suitable structure that slides on the cam surface 41c. When the rotor 35 rotates R, the anti-rotation thrust member 41 is pushed axially along the cam surface 41c.

[0026] In the example described above, the rotor 35 also acts as an action member and directly drives the thrust member 41. However, as shown in Figure 4, the rotor 35 may be coupled to an independent action member 45 in a driving manner, and this action member 45 may generate rotational motion R to drive the thrust member 41. Furthermore, the cam surface 41c does not have to be on the thrust member 41, but may be provided by the rotor 35 or the action member 45. Alternatively, other intervening members may also be provided.

[0027] The connection between the rotor 35 and the action member 45 may be fixed by an interference fit as shown in Figure 4, but it may also be by a spline or key coupling, or rotation may be transmitted by gear meshing. As already explained, if the rotor 35 is on a different shaft from the conversion mechanism 7, gear meshing would be the simplest method.

[0028] A rotatable roller 53 may be interposed between the rotor 35 or action member 45 and the cam surface 41c to ensure smooth sliding. In the example shown in Figure 2, the rotor 35 is provided with a pocket 35c for holding the roller 53, and as the rotor 35 rotates, the roller 53 rolls on the cam surface 41c, thereby driving the thrust member 41 in the axial direction. The roller 53 can be, for example, cylindrical or truncated cone-shaped. Alternatively, if a spherical shape is adopted, the conversion mechanism 7 takes the form of a ball cam mechanism.

[0029] The legs of the clutch member 11 are extended outward, for example, through the end wall 15E of the case 15, and the thrust member 41 abuts against them and drives them. Alternatively, as illustrated in Figure 4, the thrust member 41 and the clutch member 11 may move together axially by an appropriate engagement structure. Alternatively, instead of engagement, they may be joined by bolts or the like. The legs of the clutch member 11 do not have to be extended outward from the case 15, and may be joined to the thrust member 41 through an opening in the side wall of the case 15, for example. Also, as already mentioned, the thrust member 41 may be driven by a helical track or screw structure 47 as illustrated in Figure 4, instead of by a cam surface.

[0030] As can be understood from the above explanation, when the rotor 35 rotates R, the conversion mechanism 7 drives the clutch member 11 axially via the thrust member 41. As illustrated in Figure 5A, when the thrust member 41 is in its initial position x1, the clutch teeth 13 of the clutch member 11 are separated from the clutch teeth 17 of the side gear 23, meaning the clutch 10 is disengaged. As illustrated in Figure 5B, when the thrust member 41 moves to its terminal position x3, the clutch member 11 also moves, and the clutch teeth 13 and 17 mesh with each other, meaning the clutch 10 is engaged. Conversely, with rotational motion in the opposite direction, the conversion mechanism 7 moves the clutch member 11 from the position where the clutch 10 is engaged to the position where it is disengaged. An elastic body such as a spring may be used to facilitate the disengagement of the clutch 10. Alternatively, an elastic body can be used in the direction that facilitates engagement. Of course, elastic bodies are neither essential nor unique to these embodiments. In any case, the rotation angle of the rotor 35 around the axis X reflects the position of the thrust member 41. Note that the distinction between the initial position x1 and the terminal position x3 is for convenience only and does not mean that either is a steady-state position.

[0031] Referring to Figures 5C and 5D, a problem arises when the thrust member 41 is at the transition position x2, which is midway between the initial position x1 and the terminal position x3. As illustrated in Figure 5C, when the clutch teeth 13 are in a position to interfere with the clutch teeth 17, the engagement of the clutch 10 is hindered, and if the side gear 23 rotates relative to the clutch member 11 in this state, NVH occurs. As illustrated in Figure 5D, if control can be implemented to wait for the clutch teeth 13 to come to a position where they can mesh with the clutch teeth 17, the occurrence of NVH can be suppressed. That is, when the clutch member 11 is at the initial position x 1、 transition position x 2、 The ability of the clutch system to determine which of the three end positions it is in offers various advantages.

[0032] Referring to Figure 6, by utilizing the fact that the rotation angle θ of the rotor 35 reflects the position of the thrust member 41, and thus the position of the clutch member 11, the position of the clutch member 11 can be detected by measuring the rotation angle θ without directly detecting these positions. For example, when rotation angles θ1, θ2, and θ3 correspond to positions x1, x2, and x3 respectively, the rotation angle θ is set to an appropriate reference value θ. a ,θ b By comparing with the following, the clutch system can determine the state of clutch 10. Reference value θ a ,θ b These can be predetermined, taking into account the mechanical play of the conversion mechanism 7 and other elements, and can also be stored in the memory of the ECU 85.

[0033] To measure the rotation angle θ of the rotor 35, the inductance of the electrical circuit 81 can be used. For example, the solenoid 31 has its own inductance, and by superimposing an alternating current on the drive current applied to it, the change in inductance due to the rotation of the rotor 35 can be read, and thus the rotation angle θ can be read. In this example, the electrical circuit 81 is equipped with an oscillator that generates an alternating current of a specific frequency and superimposes this on the current for driving the actuator 1. The superimposed power can be made sufficiently small compared to the power for driving so as not to affect the behavior of the rotor 35. The frequency can also be appropriately selected considering the need to avoid affecting the behavior of the rotor 35 and to separate it from the power for driving.

[0034] Referring to Figure 7, in superimposed AC power, the current I1 has a phase difference Δφ relative to the voltage V. refThis occurs. When the rotor 35 moves from the first position to the second position relative to the stator 33, the inductance of the solenoid 31 changes according to the change in position, and as a result, the phase difference Δφ between the current I2 and the voltage V also changes. On the other hand, if an appropriate band-pass filter (or in some cases, a high-pass filter or a low-pass filter) is used, the superimposed AC power can be easily separated from the power for driving, so it is also easy to detect the phase difference Δφ from there. The ECU 85 can read the phase difference Δφ via the electric circuit 81 and calculate the rotation angle θ.

[0035] Of course, instead of the rotor 35, the change in inductance due to the movement of other members may be read. Alternatively, the clutch system may include a separate electromagnetic coil independent of the solenoid 31, and the change in inductance of such an electromagnetic coil may be read. Also, instead of the change in inductance, the change in capacitance may be utilized.

[0036] Alternatively, the clutch system can be provided with means for reading the rotation angle θ of the rotor 35. An example of such means is an encoder attached to the rotor 35, the action member 45 or elements rotating together with these, and a proximity sensor installed in relation to such an encoder. For example, each time a notch provided in the encoder passes in front of the proximity sensor, the proximity sensor outputs a corresponding pulse, and by counting this by the ECU 85 or other ECUs, the rotation angle θ can be read.

[0037] Based on the measured rotation angle θ, the ECU 85 determines whether the clutch 10 is disengaged or engaged according to an algorithm such as the flowchart illustrated in FIG. 8.

[0038] The ECU 85 first checks whether the means and system for detecting the rotation angle operate normally. Next, the ECU 85 reads the rotation angle θ using the means for detecting the rotation angle, and also reads appropriate reference values θ a , θ b from the storage device.

[0039] Next, the ECU85 takes the rotation angle θ as a reference value θ. a ,θ b Compare with θ1 (initial position). For example, if the rotation angle θ is θ a During this time, it is determined that the clutch 10 is disengaged, and the rotation angle θ is θ a From θ b During this time, the clutch 10 is determined to be in a transition state, and the rotation angle θ is θ b When the distance is between θ3 (end position), it can be determined that the clutch 10 is engaged.

[0040] The ECU85 can store the judgment result in a memory device and use it for other control purposes, and it can also transmit the judgment result to other ECUs via CAN communication.

[0041] The ECU 85 can also use the determination result to control the actuator 1. Referring to Figure 9, the ECU 85 determines whether the conditions for continuing control are met, and if it should continue, it drives the electrical circuit 81 to engage (or disengage) the clutch 10 and applies the necessary current to the solenoid 31. Next, the ECU 85 determines whether the clutch member 11 is in the required position (engaged position or disengaged position) according to the algorithm already described. When it determines that the clutch member 11 has reached the required position, it changes the current applied to the solenoid 31 to the extent necessary to maintain the state (usually to power-saving mode). If the position of the clutch member 11 is different from the required position, it causes the electrical circuit 81 to output the current necessary to transition it to the required position. The ECU 85 also causes the electrical circuit 81 to output the current necessary to transition the clutch member 11 to the disengaged position and terminates control when the conditions for terminating control are met or when an abnormality is detected. At this time, for example, the detection of an abnormality may be transmitted to another ECU via CAN communication.

[0042] When the ECU 85 determines that the clutch member 11 is in the transition position, it may perform additional processing (indicated by symbol a in Figure 9). For example, as illustrated in Figure 10, when the clutch member 11 is in the transition position, the ECU 85 can determine whether or not the clutch member 11 will transition further. This determination may, of course, be made based on whether or not the rotation angle θ changes, or whether or not the change in rotation angle θ is commensurate with the applied current. When it is determined that the clutch member 11 will transition, the ECU 85 can perform appropriate control to engage the dog teeth. When it is determined that the clutch member 11 will not transition, the ECU 85 can further determine whether or not conditions for NVH (noise, vibration, and harshness) will be generated. When it is determined that NVH will be generated, the ECU 85 can perform processing to reduce NVH. Such processing may, for example, temporarily stop the clutch member 11 or decelerate its movement. When it is determined that NVH will not be generated, the control shown in Figure 9 may be continued.

[0043] Furthermore, any additional processing performed by ECU85 may be carried out using other ECUs. For example, ECU85 can transmit to other ECUs via CAN communication that the clutch member 11 is still in the transition position. Upon receiving such communication, the other ECU can take necessary measures, such as controlling the output of the engine or motor 61 to a certain extent, thereby reducing NVH.

[0044] Furthermore, by precisely determining the position of the clutch member, further reduction of NVH is possible. Referring again to Figure 6, if the clutch member 11 retracts beyond its initial position x1 and its back surface contacts the end wall 15E as shown in Figures 3 and 4 (contact position x0), the differential 3 may also produce abnormal noise. Also, as can be understood by referring to Figure 5B, if the clutch member 11 advances beyond its terminal position x3 and the tooth tip surface of the clutch tooth 13 contacts the tooth bottom surface of the clutch tooth 17, or if the tooth tip surface of the clutch tooth 17 contacts the tooth bottom surface of the clutch tooth 13 (contact position x4), the differential 3 may also produce abnormal noise. According to this embodiment, it is possible to determine whether or not abnormal noise may occur, or to predict whether or not abnormal noise will occur, depending on whether or not the rotation angle θ of the rotor 35 reaches angles θ0 and θ4 corresponding to the contact positions x0 and x4, respectively. Therefore, by setting an appropriate threshold to control the motor 61, these situations can be avoided, or by slowing down the rotation of the motor 61 in advance, NVH can be reduced.

[0045] As can be understood from the above explanation, according to this embodiment, the clutch system can determine the position of the clutch member without adding any special equipment, and in particular, it can determine whether or not it is in a transition state. Using this determination, the clutch system itself, or in cooperation with other systems, can perform control to reduce NVH.

[0046] Although several embodiments have been described, it is possible to modify or alter these embodiments based on the above disclosure.

Claims

1. A system for controlling a clutch that controls the transmission of torque around the rotation axis of an axle in a vehicle, An action member rotatable around the aforementioned rotation axis, A motor that is drivenly coupled to the action member and imparts rotational motion to the action member around the rotation axis, A conversion mechanism that is drivenly coupled to the action member and converts rotational motion around the rotation axis into axial motion, A clutch member constituting the clutch, which is driven by the axial motion and coupled to the conversion mechanism, and is movable bidirectionally in the axial direction from a first position where the clutch is disengaged, through a second position, to a third position where the clutch is engaged. A controller that reads the rotation angle of the motor and compares it with a reference value to determine whether the clutch member is in the first position, the second position, or the third position, A system equipped with, The clutch member is provided with dog teeth that mesh with an opposing member, thereby constituting a dog clutch, and the second position is the position in which the dog teeth interfere with the opposing member, in this system.

2. The conversion mechanism comprises a thrust member that contacts or connects to the clutch member in order to drive the clutch member, and a cam surface, screw thread, or helical track that extends along the rotation axis and is inclined in the axial direction in order to push the thrust member in the axial direction in accordance with the rotational motion, thereby positioning the clutch member to reflect the rotation angle, according to claim 1.

3. The system according to claim 1, wherein one or more of the action member, the motor, and the controller are provided with means for reading the rotation angle.

4. The system according to claim 1, wherein the controller is configured to determine whether the determined position of the clutch member matches the requested position, and if it determines that they match, it applies a current to the motor to maintain the position of the clutch member.

5. The system according to claim 1, wherein the controller is configured to determine whether the determined position of the clutch member matches the requested position, and if it determines that they do not match, it applies current to the motor to move the position of the clutch member to the requested position.

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