Engine control unit

Abstract

A P-range limit position of a range of motion of a range-change mechanism (11) is learned by rotating a motor (13) to a corresponding rotational position that corresponds to the P-range limit position. A climb correction amount is set for a learned value of the P-range limit position to correct the learned value of the P-range limit position in view of a relatively small rotation angle of the motor (13) beyond the corresponding rotational position that corresponds to the P-range limit position. The climb correction amount is set according to motor temperature information, which is a value derived from the temperature of the motor (13) and a temperature relative to the temperature of the motor (13).

Description

[0001] The present invention relates to a motor control device that controls a rotational position of an electric motor that changes or changes an actuating position of a control object.

[0002] Recently, in the automotive industry, many mechanical drive systems have been replaced by electric drive systems, each of which uses an electric motor as its drive source to meet a requirement for improving system installation space savings, a requirement for improving system assembly ease, a requirement for improving system controllability, and / or the like. For example, a range-change mechanism of an automatic transmission of a vehicle has been modified to use an electric motor as its drive source (see, for example, JP 2002-323127 A). In this case, an output shaft is connected to a rotatable shaft of the electric motor via a speed reduction mechanism, and the range-change mechanism is driven by this output shaft to change the range of the automatic transmission.In this case, the motor is equipped with an encoder or value sensor that detects the angle of rotation. When the range is changed, the motor is rotated to a target position (to a target count value) that corresponds to a target range, based on a count of the encoder's output pulses.

[0003] The rotational amount (rotation angle) of the motor is converted into the rotational amount of the control object (the actuation amount of the range-change mechanism) by a rotational transmission system, such as the speed reduction mechanism. It should be noted here that there is a backlash (movability) between adjacent components of the rotational transmission system. For example, there is a backlash (backlash) between adjacent gears of the speed reduction mechanism.Furthermore, in a case where a connecting portion having a non-circular cross section (e.g., a polygonal cross section, a D-cut cross section) provided at a distal end portion of the rotatable shaft of the speed reduction mechanism is fitted into an engagement hole of a connecting shaft of the control object, a clearance is required to facilitate the fitting operation for fitting the connecting portion of the rotatable shaft into the engagement hole of the connecting shaft of the control object.Due to the presence of backlash (movability) in the rotation transmission system that converts the rotation amount of the motor into the operation amount of the control object, even if the rotation angle of the motor is correctly controlled based on a detected value from a rotation angle sensor, an error corresponding to the backlash (movability) of the rotation transmission system is generated in the rotation angle of the connecting shaft of the control object (the operation amount of the range change mechanism). As a result, the operation amount of the range change mechanism cannot be precisely controlled.

[0004] In view of the above drawback, as shown in JP 2004-23932 A (corresponding to US Pat. No. 7,221,116 B2), the amount of backlash in the rotation transmission system is learned by executing an abutment control operation in which the motor is rotated until abutment is caused against a limiting position (a wall) of a moving range of the range-change mechanism. Subsequently, a target position is set (corrected) in light of a learning value of the limiting position learned by the abutment control operation.

[0005] Furthermore, as in the case of JP 2004-23932 A (equivalent to US 7 221 116 B2), in which the motor is rotated slightly beyond the limit position following the motor's abutment at the limit position, an excessive rotation angle of the motor exceeding the limit position is increased as the motor torque is increased. Generally, the motor torque varies depending on the motor's power source voltage. Therefore, in the case of JP 2004-23932 A (equivalent to US 7 221 116 B2), a climb correction amount is provided to account for the excessive rotation angle of the motor exceeding the limit position after the motor's abutment at the limit position at the time of executing the abutment control operation. The climb correction amount is set based on the motor's power source voltage, and the target position is corrected by the climb correction amount.

[0006] The motor torque varies depending on the motor power source voltage and also varies depending on the motor winding temperature (hereinafter referred to as the winding temperature). As the motor winding temperature increases, the resistance of the winding increases. Therefore, even when the same motor power source voltage is applied, as the motor coil temperature increases, the motor torque decreases. Thus, the pitch correction amount changes depending on the motor temperature, and the learning accuracy of the backlash amount decreases, thereby causing a decrease in the position change accuracy of the control object.

[0007] The document DE 11 2006 001 037 T5 describes a storage media housing device comprising: a housing device for accommodating storage media; a position detection device for detecting a position of the housing device; a transfer device for transferring the housing device to a desired position upon a command; a control device for outputting, when the housing device is transferred to a desired position, a damping start position of the transfer device corresponding to the previously stored desired position as a transfer control signal to the transfer device; a comparison device for comparing, when the control device controlled the housing device, a detected position of the housing device detected by the position detection device with the desired position at that time;and a position changing device for changing the transfer control signal of the control device based on the comparison result of the comparison device and for changing the damping start position of the housing device. The transfer device is provided with a motor that rotates when the housing device is transferred; wherein the comparison result obtained by the comparison device by comparing the desired position of the housing device and the detected position of the housing device detected by the position detection device shows that a difference therebetween is within a predetermined range, the transfer control device outputs a transfer control signal to the control device to attenuate a rotational force of the motor, thereby transferring the housing device to the desired position.

[0008] The present invention was made in view of the foregoing disadvantages. Therefore, an object of the present invention is to provide a motor control device capable of limiting a reduction in position change accuracy of a control object resulting from a torque change caused by a temperature of an electric motor.

[0009] To achieve the object of the present invention, a motor control device is provided that controls a rotational position of an electric motor used as a drive source for changing an operating position of a control object to a target position of the electric motor corresponding to a target operating position of the control object. The motor control device includes limit position learning means, climb correction amount setting means, reference position learning means, target position setting means, and motor temperature information determining means. The limit position learning means is for learning one of first and second limit positions of a movement range of the control object corresponding to a first and second limit position, respectively.a second rotational position of the electric motor by rotating the electric motor to a corresponding one of the first and second rotational positions, which corresponds to one of the first and second limiting positions of the movement range of the control object. The climb correction amount setting means serves to set a climb correction amount as a learning value of the one of the first and second limiting positions learned by the limiting position learning means, in order to correct the learning value of the one of the first and second limiting positions following the rotation of the electric motor to the corresponding one of the first and second rotational positions in view of the presence of a relatively small rotation angle of the electric motor at the time of learning the one of the first and second limiting positions by the limiting position learning means beyond the corresponding one of the first and second rotational positions.The reference position learning means is for learning a reference position by correcting the learning value of one of the first and second limit positions by the climb correction amount. The target position setting means is for setting the target position of the electric motor based on the reference position at the time of changing the operating position of the control object. The motor temperature information determining means is for acquiring or estimating motor temperature information, which is one of a temperature of the electric motor and a temperature related to the temperature of the electric motor. The climb correction amount setting means sets the climb correction amount according to the motor temperature information.

[0010] To achieve the object of the present invention, a motor control device is further provided, which comprises a motor control device, a reference position learning device, a backlash amount learning device, a target position setting device, and a motor temperature information determining device. The motor control device serves to control a rotational position of an electric motor used as a drive source for changing an operating position of a control object to a target position of the electric motor, which corresponds to a target operating position of the control object. The reference position learning device serves to determine one of first and second limit positions of a movement range of the control object, which correspond to a first and second limit position, respectively.corresponding to a second rotational position of the electric motor, as a reference position by rotating the electric motor to a corresponding one of the first and second rotational positions corresponding to one of the first and second limiting positions of the movement range of the control object. The backlash amount learning means is for learning a backlash amount in a rotation transmission system located between the electric motor and the control object by rotating the electric motor to each of the first and second rotational positions. The target position setting means is for setting the target position of the electric motor in view of a learning value of the backlash amount based on a learning value of the reference position learned by the reference position learning means at the time of changing the operation position of the control object.The motor temperature information determining means is for detecting or estimating motor temperature information, which is one of a temperature of the electric motor and a temperature related to the temperature of the electric motor. The backlash amount learning means executes the backlash amount learning after at least one learning execution condition is met, which includes a temperature falling within a specific temperature range indicated by the motor temperature information.

[0011] The invention, together with its additional objects, features and advantages, will be best understood from the following description, the appended claims and the accompanying drawings in which: Fig. 1 is a perspective view of a range changing device according to a first embodiment of the present invention; Fig. 2 is a schematic diagram showing an entire control system structure of the area switching device according to the first embodiment; Fig. 3 is a schematic diagram for describing a relationship between holding recesses of a detent lever and an engaging portion of a detent spring; Fig. 4 is a diagram showing an example of a map used to calculate a climb correction amount based on an AT oil temperature and a power source voltage of a motor serving as parameters, according to the first embodiment; Fig. 5 is a flowchart showing a flow of a play amount learning routine according to the first embodiment; Fig. 6 is a flowchart showing a flow of a play amount learning routine according to a second embodiment of the present invention; Fig. 7 is a flowchart showing a flow of a reference position learning routine according to the second embodiment of the present invention; and Fig. 8 is a schematic diagram showing a range change control operation from a P range to an R range before executing backlash amount learning according to a third embodiment of the present invention.

[0012] Hereinafter, first to third embodiments of the present invention, which is embodied in a range shift control apparatus (including an engine control apparatus) of an automatic transmission, will be described with reference to the accompanying drawings. (FIRST EXAMPLE)

[0013] A first embodiment of the present invention is described in relation to Fig. 1 to 5 described.

[0014] First, a structure of a range switching mechanism (a control object) 11 is schematically shown below with respect to Fig. 1 and Fig. 2 described.

[0015] The range change mechanism 11 is used to change a range of an automatic transmission 12 between a parking range (P), a reverse range (R), a neutral range (N), and a drive range (D). An electric motor 13 serving as a drive source of the range change mechanism 11 may be, for example, a synchronous motor such as a switched reluctance (SR) motor. The motor 13 has a speed reduction mechanism 14 (see Fig. 2) that reduces a rotational speed of a rotor of the motor 13. Furthermore, the motor 13 is provided with an output shaft sensor 16 for detecting a rotation angle of an output shaft 15 that is engaged with and thereby connected to a rotation shaft of the speed reduction mechanism 14. The output shaft sensor 16 is a rotation angle sensor (e.g., a potentiometer) whose output voltage changes linearly in response to the rotation angle of the output shaft 15 of the speed reduction mechanism 14 of the motor 13. The current rotation angle of the output shaft 15 is determined based on this output voltage. Then, based on the current rotation angle of the output shaft 15, it is possible to determine which of the P range, the R range, the N range, and the D range is the current range.

[0016] A detent lever 18 is attached to the output shaft 15 for changing a manual valve 17 of a hydraulic circuit of the automatic transmission 12. An L-shaped parking rod 19 is attached to the detent lever 18. A conical body 20 provided at a distal end portion of the parking rod 19 contacts a lock lever 21. The lock lever 21 is pivoted upward or downward about a shaft 22 depending on a position of the conical body 20 to lock or release a parking gear 23. The parking gear 23 is provided on an output shaft of the automatic transmission 12. When the actuating gear 23 is locked by the lock lever 21, a drive wheel of the vehicle is held in a non-rotatable state (a parking state).

[0017] A spool valve 24 of the manual valve 17 is connected to the detent lever 18. When the detent lever 18 is rotated by the motor 13 integrally with the output shaft 15, an operation amount of the manual valve 17 (a position of the spool valve 24) is changed to change the range of the automatic transmission 12 to the corresponding one of the P range, the R range, the N range, and the D range. Four retaining recesses 25 (see Fig. 3), which correspond to the above-mentioned four areas, respectively, are formed in the locking lever 18 in order to hold the slide valve 24 in the respective position corresponding to one of the four areas.

[0018] A detent spring 26 is attached to the manual valve 17 to hold the detent lever 18 in the respective position corresponding to one of the four ranges. When an engaging portion 27 provided at a distal end of the detent spring 26 is received in the target range holding recess 25 in the detent lever 18, the detent lever 18 is held at the rotation angle of the target range. This maintains the position of the spool valve 24 of the manual valve 17 in the target range position. In the P range, the parking rod 19 is moved toward the lock lever 21, so that a large-diameter portion of the conical body 20 pushes the lock lever 21 upward. As a result, a projection 21a of the lock lever 21 is received in the parking gear 23 to lock the parking gear 23. Thus, the output shaft (drive gear) of the automatic transmission 12 is placed in the locked state (the parking state).

[0019] In any of the three ranges other than the P range, the parking rod 19 is moved in a direction away from the lock lever 21. This moves the large-diameter portion of the tapered body 20 away from the lock lever 21, so that the lock lever 21 is pivoted downward. Thus, the projection 21a of the lock lever 21 is released from the timing gear 23 to unlock the timing gear 23. Therefore, the output shaft of the automatic transmission 12 is maintained in the rotatable state (vehicle drivable state).

[0020] The motor 13 is provided with an encoder 31 for detecting the rotation angle of the rotor of the motor 13. The encoder 31 may be, for example, a magnetic rotary encoder. The encoder 31 outputs pulse signals of an A-phase, a B-phase, and a Z-phase in synchronization with the rotation of the rotor of the motor 13 to a range-change controller 32. An ECU 33 (a motor controller) of the range-change controller 32 counts the rising edges / falling edges of the A-phase and B-phase signals output from the encoder 31. Based on this encoder count, the ECU 33 sequentially changes the excitation phases of the motor 13 in a predetermined order through motor drivers 34, 35.

[0021] At this time, the rotation direction of the rotor of the motor 13 is determined based on the generation order of the A-phase and B-phase signals (i.e., based on which of the A-phase signal and the B-phase signal is generated first). In the case of normal rotation (i.e., rotation in the rotation direction from the P range to the D range), the encoder count is counted up. In contrast, in the case of reverse rotation (i.e., rotation in the rotation direction from the D range to the P range), the encoder count is counted down. In this way, when the motor 13 is rotated in either of the normal rotation direction and the reverse rotation direction, the appropriate relationship between the encoder count and the rotation angle of the motor 13 is maintained.Thereby, in each of the normal rotation direction and the reverse rotation direction, the rotation angle of the motor 13 is appropriately detected based on the encoder count value, and the winding of each corresponding phase corresponding to the detected rotation angle is appropriately energized to drive the motor 13. It should be noted here that the Z-phase signal (index signal) of the encoder 31 is used to detect a reference rotation angle of the rotor of the motor 13.

[0022] The rotation amount (angle of rotation) of the motor 13 is converted into the actuation amount of the range change mechanism 11 (the sliding amount of the actuator rod 19) by the rotation transmission system, which includes the speed reduction mechanism 14, the output shaft 15, and the detent lever 18. It should be noted that there is a play (movability) between the components of the rotation transmission system.For example, in a case where there is a backlash between the adjacent gears of the speed reduction mechanism 14, and where a connecting portion formed at a distal end portion of the rotatable shaft of the motor 13 and having a non-circular cross section is fitted into and connected to an engagement hole of the output shaft 15, a clearance must be provided therebetween in order to facilitate the engagement operation between the connecting portion of the rotatable shaft of the motor 13 and the engagement hole of the output shaft 15.

[0023] Furthermore, as in Fig. As shown in Fig. 3, when the engaging portion 27 of the detent spring 26 is received in the retaining recess 25 of, for example, the P range or the D range, a small gap (movability) exists between the engaging portion 27 and a side wall of the retaining recess 25. As described above, in the rotation transmission system that converts the rotation amount of the motor 13 into the operation amount of the range change mechanism 11 (the sliding amount of the parking rod 19), backlash (movability) exists between the respective components of the rotation transmission system. Therefore, even if the rotation amount (rotation angle) of the motor 13 is appropriately controlled based on the encoder count value, an error corresponding to the backlash (movability) of the rotation transmission system is generated in the operation amount of the range change mechanism 11.As a result, the amount of operation of the range change mechanism 11 cannot be properly controlled.

[0024] To address the aforementioned drawback, the ECU 33 of the first embodiment has a learning function for learning the amount of backlash (hereinafter referred to as the backlash amount) in the rotation transmission system. This learning function serves as backlash amount learning means. More specifically, at the time of learning the amount of backlash in the rotation transmission system, the motor 13 is rotated in the reverse direction until the engaging portion 27 of the detent spring 26 abuts against a side wall 30 of the P-range holding recess 25 (hereinafter referred to as a P-range wall 30), which is a P-range side limiting position of the moving range of the range switching mechanism 11, to learn an encoder count value (a corresponding rotational position of the motor 13) GNp of the P-range wall position (hereinafter referred to as a P-range wall position learning value).This control operation is hereinafter referred to as a P-range wall abutment control operation. Furthermore, the motor 13 is rotated in the normal direction until the engaging portion 27 of the detent spring 26 abuts against a side wall 40 of the D-range holding recess 25 (hereinafter referred to as a D-range wall 40), which is a D-range-side limit position of the moving range of the range switching mechanism 11, to learn an encoder count value (a corresponding rotational position of the motor 13) GNd of the D-range wall position (a D-range wall position learning value). This control operation is hereinafter referred to as a D-range wall abutment control operation. The P-range wall position learning function serves as a limit position learning means.

[0025] Thereafter, the amount of change (the amount of increase / decrease) of the encoder count from the P-range wall position to the D-range wall position is obtained as an actual measured value ΔNact of the moving range of the range switching mechanism 11. Subsequently, the amount of difference between the actual measured value ΔNact of the moving range and a designed or given value ΔNs of the moving range is learned as the backlash amount ΔG in the rotation transmission system. ΔNact=GNd−GNp ΔG=ΔNact−ΔNs

[0026] Furthermore, at the time of executing the P-range wall abutment control operation, the engaging portion 27 of the detent spring 26 slightly ascends a flank of the side wall 30 of the retaining recess 25 through a relatively small angle, while the engaging portion 27 of the detent spring 26 maintains abutment against the side wall 30 of the P-range retaining recess 25 of the detent lever 18. In the first embodiment, in view of the presence of this slight ascending angle, a climb correction amount ΔNover is set for the P-range wall position encoder count value GNp (this function serves as climb correction amount setting means). The P-range wall position encoder count value GNp is corrected by the climb correction amount ΔNover so that the reference position learning value Np is obtained (this function serves as reference position learning means). Np=GNp−ΔNover

[0027] Thereafter, at the time of rotating the motor 13 to a target position (a target count value), the target position is set based on the learned value Np of the reference position in view of a learned value ΔG of the amount of backlash in the rotation transmission system (this function serves as a target position setting means). In this way, at the time of executing the P-range wall abutment control operation, even in the case where the engaging portion 27 of the detent spring 26 slightly ascends the flank of the side wall 30 of the P-range retaining recess 25 at the relatively small angle while maintaining abutment against the side wall 30 of the P-range retaining recess 25, and / or in the case where backlash (movability) exists in the rotation transmission system, the target position can be set in view of such a climbing angle and / or in view of the backlash in the rotation transmission system.Therefore, the operation amount of the range change mechanism 11 can be controlled more appropriately.

[0028] The climb angle of the engaging portion 27 of the detent spring 26 over the flank of the side wall 30 of the P-range holding recess 25 at the time of executing the P-range wall abutment control operation (at the time of learning the reference position) is increased as the torque of the motor 13 is increased. Therefore, it is desirable to increase the climb correction amount ΔNover as the torque of the motor 13 is increased, and vice versa.

[0029] In this case, the torque of the motor 13 varies depending on the power source voltage of the motor 13 and also depending on the winding temperature of the motor 13. This means that when the winding temperature of the motor 13 increases, the resistance value of the winding of the motor 13 increases. Therefore, even if the power source voltage of the motor 13 remains the same, the torque of the motor 13 decreases when the winding temperature of the motor 13 increases. In addition, the motor 13, which drives the range change mechanism 11, is installed in the automatic transmission. Therefore, the temperature of the automatic transmission has an influence to cause the temperature of the motor 13 to change. Furthermore, automatic transmissions recently have an oil temperature sensor 36 that detects the oil temperature to perform the gear change control operation.Therefore, it is possible to use the oil temperature detected by the oil temperature sensor 36 as the temperature information (temperature of the automatic transmission) related to the temperature of the engine 13.

[0030] In view of the foregoing, according to the first embodiment, the oil temperature of the automatic transmission (hereinafter referred to as an AT oil temperature) is detected with the oil temperature sensor 36 (an engine temperature information determining means) provided in the automatic transmission. The detected AT oil temperature is used as engine temperature information related to the temperature of the engine 13. Furthermore, an image of the climb correction amount ΔNover of Fig. 4 to calculate the climb correction amount ΔNover given the AT oil temperature and the power source voltage of the motor 13, which are used as parameters. By using the image of Fig. 4, the climb correction amount ΔNover corresponding to the AT oil temperature detected at the time of executing the P-range wall attachment control operation (at the time of learning the reference position) as well as the power source voltage (the battery voltage) of the motor 13 is calculated.

[0031] When the AT oil temperature (the temperature of the motor 13) increases, the resistance value of the winding of the motor 13 increases, causing the reduction of the torque of the motor 13. In view of this circumstance, the Fig. 4, the map of the climb correction amount ΔNover is set such that the climb correction amount ΔNover decreases as the AT oil temperature (the temperature of the motor 13) increases. In addition, as the power source voltage of the motor 13 decreases, the torque of the motor 13 decreases. Given this circumstance, the Fig. 4 is set such that the climb correction amount ΔNover decreases as the power source voltage of the motor 13 decreases.

[0032] The calculation of the learning value Np of the reference position corrected by the climb correction amount ΔNover is carried out as follows according to a reference position learning routine described in Fig. 5 is shown.

[0033] The reference position learning routine of Fig. 5 is repeatedly executed at predetermined intervals during the ON period of the ignition switch (during the ON period of the electric power source of the ECU 33) and serves as the climb correction amount setting means and the reference position learning means. When this routine begins, it is determined in step 101 whether a reference position learning completion flag Xbase is in an OFF state, indicating an incomplete state of the reference position learning. If it is determined in step 101 that the reference position learning completion flag Xbase is in an ON state (a learning completion state), the present routine is terminated without executing any further steps. In this way, the reference position learning is executed only once during the ON period of the ignition switch.The reference position learning completion flag Xbase is reset to the OFF state by an initialization routine (not shown) executed immediately after the ignition switch is turned on.

[0034] On the other hand, if it is determined in step 101 that the reference position learning completion flag Xbase is in the OFF state (learning incomplete state), control proceeds to step 102. In step 102, it is determined whether a P-area wall abutment completion flag Xp is in an ON state to determine whether the P-area wall abutment control operation is completed. If it is determined in step 102 that the P-area wall abutment completion flag Xp is in an OFF state (state before completion of the P-area wall abutment control operation), the present routine is terminated without executing any further steps.

[0035] On the other hand, if it is determined in step 102 that the P-range wall attachment termination flag Xp is in an ON state (a state after the termination of the P-range wall attachment control operation), control proceeds to step 103. In step 103, the AT oil temperature detected by the oil temperature sensor 36 at the time of executing the P-range wall attachment control operation and the power source voltage (the battery voltage) of the motor 13 are sensed. Thereafter, in step 104, the climb correction amount ΔNover corresponding to the AT oil temperature detected at the time of executing the P-range wall attachment control operation and the power source voltage of the motor 13 are calculated in view of the Fig. 4 shown image of the climb correction amount ΔNover.

[0036] Thereafter, control proceeds to step 105, where the P-range wall position encoder count value GNp learned by the P-range wall abutment control process is read. Next, in step 106, this P-range wall position encoder count value GNp is corrected by the climb correction amount ΔNover to obtain the reference position learning value Np, and this reference position learning value Np is stored in a memory of the ECU 33. Np=GNp−ΔNover

[0037] Next, in the subsequent step 107, the reference position learning completion flag Xbase is set to the ON state (the completed state of learning) and the present routine is ended.

[0038] Thereafter, at the time of rotating the motor 13 to the target position (the target count value Acnt), the target position (the target count value Acnt) is set based on the learning value Np of the reference position in view of the learning value ΔG of the backlash amount in the rotation transmission system.

[0039] For example, in the case of shifting from the P range to the D range, the target count value Acnt is set to the value obtained by adding the learning value ΔG of the backlash amount in the rotation transmission system to the target count value (Np + Nd) of the D range calculated at the time of design. Acnt=Np+Nd+ΔG

[0040] Similarly, in the case of switching from the P range to the R range, the target count value Acnt is set to the value obtained by adding the learning value ΔG of the backlash amount in the rotation transmission system to the target count value (Np + Nr) of the R range calculated at the time of design. Here, Nr represents the design value between the P range and the R range. Acnt=Np+Nr+ΔG

[0041] According to the first embodiment, as discussed above, at the time of executing the P-range wall abutment control operation, the engaging portion 27 of the detent spring 26 can slightly ascend the flank of the side wall 30 of the retaining notch 25 of the detent lever 18 through the relatively small angle, while the engaging portion 27 of the detent spring 26 maintains abutment against the side wall 30 of the P-range retaining notch 25 of the detent lever 18. Given this slight ascending angle, the ascending correction amount ΔNover is set for the P-range wall position encoder count value GNp. At this time, the ascending correction amount ΔNover is set according to the AT oil temperature detected by the oil temperature sensor 36 provided in the automatic transmission.Therefore, in response to the change in the actual pitch angle caused by the change in the torque of the motor 13 due to the temperature change of the motor 13, it is possible to set the appropriate pitch correction amount ΔNover in response to the temperature of the motor 13 detected at the time of executing the P-range wall abutment control operation. Thus, the correction accuracy of the reference position Np can be improved by using the pitch correction amount ΔNover. As a result, it is possible to limit the reduction in the range change accuracy caused by the torque change due to the temperature change of the motor 13.

[0042] Furthermore, in the first embodiment, the automatic transmission oil temperature detected by the given oil temperature sensor 36 installed in the automatic transmission is used as the engine temperature information. This allows the engine temperature information to be obtained without reinstalling an additional temperature sensor for detecting the temperature of the engine 13. As a result, it is possible to meet the requirement for reducing costs.

[0043] It should be noted, however, that the temperature of the motor 13 is actually measured on demand by providing a temperature sensor at the motor 13. (SECOND EXAMPLE)

[0044] In the first embodiment, the influence of the torque variation caused by the change in the temperature of the motor 13 is substantially eliminated or reduced by using the climb correction amount ΔNover. Alternatively, in a second embodiment, the influence of the torque variation caused by the change in the temperature of the motor 13 is substantially eliminated or reduced by performing a Fig. 6 is substantially eliminated. With this routine, the amount of play ΔG in the rotation transmission system is learned only at the time when the AT oil temperature, which relates to the temperature of the engine 13, is within a certain temperature range. Furthermore, according to the second embodiment, the Fig. 7 is executed to learn the P-range wall position as the reference position at the time of setting the target range to the P range for the first time immediately after the ignition switch is turned on (immediately after the power source of the ECU 33 is turned on). The procedure of each of these routines is described in detail below.

[0045] The game amount learning routine of Fig. 6 is repeatedly executed at predetermined intervals during the ON period of the ignition switch (during the ON period of the power source of the ECU 33) and serves as the backlash amount learning means. When this routine begins, it is determined in step 201 whether a backlash amount learning completion flag Xg is in an OFF state (a state before the completion of the backlash amount learning). If it is determined in step 201 that the backlash amount learning completion flag Xg is in an ON state (a state after the completion of the backlash amount learning), the present routine is terminated without executing any further steps. In this way, backlash amount learning is executed only once during the ON period of the ignition switch. The backlash amount learning completion flag Xg is reset to the OFF state by an initialization routine (not shown) executed immediately after the ignition switch is turned on.

[0046] On the other hand, if it is determined that the backlash amount learning completion flag Xg is in the OFF state (the state before the backlash amount learning is completed), control proceeds to step 202. In step 202, it is determined whether the AT oil temperature is equal to or higher than a predetermined temperature (for example, equal to or higher than an engine warm-up completion temperature) to determine whether the AT oil temperature detected by the oil temperature sensor 36 is within the specified temperature range in which learning of the backlash amount ΔG is permitted.

[0047] Here, the specific temperature range in which the learning of the backlash amount ΔG is permitted is not limited to the temperature range equal to or higher than the predetermined temperature (for example, equal to or higher than the engine warm-up completion temperature), and may alternatively be a temperature range equal to or higher than the predetermined temperature or a predetermined temperature range (a range between a temperature A°C and a temperature B°C, where the temperature A°C and the temperature B°C may be any suitable temperatures, respectively). Importantly, the temperature range of the engine 13 (the AT oil temperature) for performing the learning of the backlash amount ΔG is limited, so that the learning of the backlash amount ΔG is performed under the condition where the variation in the torque of the engine 13 caused by the temperature of the engine 13 is relatively small.In the second embodiment, the temperature range equal to or higher than the predetermined temperature (ie, equal to or higher than the engine warm-up completion temperature) and the temperature range that can be easily satisfied is set as a learning execution condition for executing the learning of the backlash amount ΔG. Thereby, the learning of the backlash amount ΔG is executed at the earliest possible stage.

[0048] If it is determined in step 202 that the AT oil temperature is less than the predetermined temperature, then it is determined that the learning of the backlash amount ΔG is prohibited. Thus, control proceeds to step 211. In step 211, a standard value (e.g., a designed average value of the backlash amount specified in design data, an average value of the backlash amounts of selected actual products, an average value of the backlash amounts of selected actual products, or an actual measurement value of a standard product) is set as the backlash amount ΔG, and the present routine is terminated.

[0049] On the other hand, if it is determined in step 202 that the AT oil temperature is equal to or higher than the predetermined temperature, then it is determined that the AT oil temperature is in the temperature range in which the learning of the backlash amount ΔG is permitted. Therefore, control proceeds to step 203, in which it is determined whether the target range is the P range, and it is also determined whether a backlash amount learning time P-range wall application completion flag Xpg is in an OFF state (a state before completion of a backlash amount learning time P-range wall application). In step 203, if it is determined that the target range is the P range and the backlash amount learning time P-range wall application completion flag Xpg is in the OFF state, YES is returned, and thereby the execution condition for executing the P-range wall application control process is satisfied.Therefore, after YES is returned in step 203, control proceeds to step 204 in which the P-range wall position control routine is executed, and an encoder count value Npg of the P-range wall position (a play amount learning time P-range wall position learning value) is stored in the memory of the ECU 33, and control proceeds to step 205.

[0050] On the other hand, when NO is returned in step 203, that is, when the game amount learning time P-area wall installation completion flag Xpg is in the ON state (the state after the game amount learning time P-area wall installation is completed), control proceeds to step 205 without executing the P-area wall installation control process (step 204).

[0051] In step 205, it is determined whether the target range is the D range, and it is also determined whether a play amount learning time D-range wall attachment completion flag Xdg is in an OFF state (a state before completion of the play amount learning time D-range wall attachment). In step 205, if it is determined that the target range is the D range and the play amount learning time D-range wall attachment completion flag Xdg is in the OFF state, YES is returned, thereby satisfying the execution condition for executing the D-range wall attachment control process. Therefore, after returning YES in step 205, control proceeds to step 206 in which the D-range wall abutment control process is executed, and an encoder count value Ndg of the D-range wall position (a play amount learning time D-range wall position learning value) is stored in the memory of the ECU 33, and control proceeds to step 207.

[0052] On the other hand, when NO is returned in step 205, that is, when the game amount learning time D-area wall installation completion flag Xdg is in the ON state (the state after the game amount learning time D-area wall installation is completed), control proceeds to step 207 without executing the D-area wall installation control process (step 206).

[0053] In this step 207, it is determined whether both the P-range wall attachment control process and the D-range wall attachment control process have been completed (i.e., whether the current state is where the P-range wall attachment completion flag Xpg = ON and the D-range wall attachment completion flag Xdg = ON). If it is determined in step 207 that either the P-range wall attachment control process or the D-range wall attachment control process has not been completed, control proceeds to step 211. In step 211, the default value is set as the clearance amount ΔG, and the present routine is terminated.

[0054] On the other hand, if it is determined in step 207 that both the P-range wall abutment control process and the D-range wall abutment control process are completed, control proceeds to step 208. In step 208, an actual measurement value ΔNact of the moving range of the motor 13 (the moving range of the detent lever 18) from the P-range wall 30 to the D-range wall 40 is calculated using the following equation based on the play amount learning time-P-range wall position learning value Npg and the play amount learning time-D-range wall position learning value Ndg. ΔNact=Ndg−Npg

[0055] Thereafter, control proceeds to step 209. In step 209, the difference between the actual measured value ΔNact of the moving range of the motor 13 (the moving range of the detent lever 18) and the design value ΔNs of the moving range of the motor 13 is learned as the backlash amount ΔG in the rotation transmission system, which is then stored in the memory of the ECU 33. ΔG=ΔNact−Ns

[0056] Here, the given value ΔNs of the motion range may be calculated in advance based on the design data, or it may be an average value of the motion ranges of selected actual products that are mass-produced (for example, an average value of the measured motion ranges of the standard products).

[0057] Thereafter, control proceeds to step 210, in which the game amount learning completion flag Xg is set to the ON state indicating completion of the game amount learning, and the present routine is terminated.

[0058] The reference position learning routine of Fig. 7 is repeatedly executed at predetermined intervals during the ON period of the ignition switch (during the ON period of the power source of the ECU 33) and serves as the reference position learning means. When this routine begins, it is determined in step 301 whether the reference position learning completion flag Xbase is in the OFF state, which indicates the incomplete state of the reference position learning. If it is determined in step 301 that the If the reference position learning completion flag Xbase is in the ON state (learning completion state), this routine is terminated without executing any further steps. Thus, the reference position learning is executed only once during the ON period of the ignition switch. The reference position learning completion flag Xbase is reset to the OFF state by an initialization routine (not shown) executed immediately after the ignition switch is turned on.

[0059] On the other hand, if it is determined in step 301 that the reference position learning completion flag Xbase is in the OFF state (learning incomplete state), control proceeds to step 302. In step 302, it is determined whether the target range is the P range. If it is determined in step 302 that the target range is not the P range, the present routine is terminated without executing the subsequent steps.

[0060] If it is determined in step 302 that the target range is the P range, the execution condition for executing the P range wall abutment control process is satisfied. Therefore, control proceeds to step 303, where the P range wall abutment control routine is executed. Next, in step 304, the P range wall position encoder count value GNp is stored as the reference position learning value Np in the memory of the ECU 33. At this time, the P range wall position encoder count value GNp may be possibly corrected by the slope correction amount ΔNover corresponding to the power source voltage of the motor 13 to obtain the reference position learning value Np (at this time, it is not necessary to consider the temperature of the motor 13). Then, at the subsequent step 305, the reference position learning completion flag Xbase is set to the ON state (the completed state of learning) and the present routine is terminated.

[0061] Also in the second embodiment, at the time the motor 13 rotates to the target position (the target count value Acnt), the target position (the target count value Acnt) is set based on the learning value Np of the reference position in view of the backlash amount ΔG. If the learning of the backlash amount ΔG has not been performed, at this time the standard value of the backlash amount ΔG (for example, the design average value of the backlash amount, the average value of the backlash amounts of mass-produced products, the average value of the backlash amounts of mass-produced products, or the actual measurement value of the standard product) is set as the backlash amount ΔG. Further, if the learning of the backlash amount ΔG has been completed, the learning value of the backlash amount ΔG is used.

[0062] According to the second embodiment, the backlash amount ΔG in the rotation transmission system is learned while the AT oil temperature, which is the temperature information related to the temperature of the engine 13, is within the specified temperature range. Thus, the learning of the backlash amount ΔG can be performed in the state where the variability of the torque of the engine 13 caused by the temperature of the engine 13 is relatively small. In this way, the learning accuracy of the backlash amount ΔG can be improved to limit the reduction in range switching accuracy caused by the torque variation caused by the change in the temperature of the engine 13.

[0063] Furthermore, in the second embodiment, when the P range is set as the target range for the first time immediately after the ignition switch is turned on (immediately after the power source of the ECU 33 is turned on), the P range wall position is learned as the reference position. The target position is set based on the learned value Np of the reference position in view of the standard value of the backlash amount ΔG, instead of the learned value of the backlash amount ΔG in the case where the learning of the backlash amount ΔG has not yet been completed. Therefore, even in the case where the learning of the backlash amount ΔG has not been completed, the target position can be set with assured accuracy. (THIRD EXAMPLE)

[0064] In the second embodiment, the target position is set based on the learning value Np of the reference position in view of the standard value of the play amount ΔG instead of the learning value of the play amount ΔG in the case where the learning of the play amount ΔG has not been completed. Alternatively, according to a third embodiment shown in Fig. As shown in Fig. 8, when the P range is set as the target range for the first time immediately after the ignition switch is turned on (immediately after the power source of the ECU 33 is turned on), the P range wall position is learned as the reference position. Furthermore, in the case where the learning of the backlash amount ΔG has not been completed, an overrun control operation is executed at the time of range switching, so that the motor 13 is rotated beyond the target range position (overrun) and thereafter reversed. At this time, the overrun amount of the motor 13 and the reverse amount of the motor 13 are set to the same value. Furthermore, a given maximum value ΔGmax of the backlash amount in the rotation transmission system is set as the overrun amount.

[0065] As it is in Fig.For example, as shown in Fig. 8, in the case where the range is switched from the P range to the R range before learning the backlash amount ΔG, a value (Np + Nr + ΔGmax) obtained by adding the excess amount ΔGmax to the given target count value (Np + Nr) of the R range is set as the target count value. In this way, the motor 13 is rotated in the direction (the normal rotation direction) from the P range to the R range, and the operating position of the detent lever 18 reaches the original target position of the R range, and the rotation position of the motor 13 goes beyond the original target position of the R range.

[0066] After this overshoot is resolved, the target count value is reset to the original target count value (Np + Nr) of the R range. In this way, the rotational position of the motor 13 is reversed by the overshoot amount ΔGmax (the design maximum value of the backlash amount). At this time, the detent lever 18 is not reset, and only the motor 13 is rotated by the amount corresponding to the backlash (movability) in the rotation transmission system.

[0067] In this case, when the overshoot amount ΔGmax of the motor 13 becomes larger than the actual backlash amount in the rotation transmission system, the detent lever 18 is moved beyond the target position by the amount corresponding to a difference between the overshoot amount ΔGmax and the backlash amount. However, even in such a case, if the overshoot amount ΔGmax and the backlash amount are set to the same value, the operating position of the detent lever 18 can be reliably returned to the target position by the backlash amount of the motor 13. In this way, even before the backlash amount ΔG is learned, the range can be appropriately switched to the target range without being affected by the backlash amount ΔG.

[0068] After learning the backlash amount ΔG at the time of range switching, the target count value (target position) is set based on the learned value of the backlash amount ΔG. This stops the motor 13 at the position consistent with the target count value without overrunning the motor 13.

[0069] In the range switching device of each of the first and third embodiments, the range is switched among four ranges, namely, the P range, the R range, the N range, and the D range. In addition to the four ranges, another range or ranges such as a second range (2) and / or a lower range (L) may be added. Here, it should be understood that the first and second embodiments can be applied to the range switching device that switches the range between two or more ranges. Furthermore, the fourth embodiment can be applied to the range switching device that switches the range between three or more ranges.

[0070] Furthermore, the present invention is not limited to the range changing device and can be applied to any other type of position changing device that uses the motor as its drive source.

[0071] In each of the first to third embodiments, the range shift controller 32 may constitute the engine control unit of the present invention. Furthermore, the encoder 31, the output shaft sensor 16, and / or the oil temperature sensor 36 may also constitute part of the engine control unit.

[0072] Additional advantages and modifications will be apparent to those skilled in the art. The invention, in its broader sense, is therefore not limited to the specific details, representative devices, and illustrated examples shown and described.

[0073] A P-range-side limit position of a moving range of a range change mechanism is learned by rotating a motor to a corresponding rotational position corresponding to the P-range-side limit position. A climb correction amount is set for a learned value of the P-range-side limit position to correct the learned value of the P-range-side limit position in view of a relatively small rotation angle of the motor beyond the corresponding rotational position corresponding to the P-range-side limit position. The climb correction amount is set according to motor temperature information, which is one of a temperature of the motor and a temperature related to the temperature of the motor.

Claims

[1] An engine control device that controls a rotational position of an electric motor (13) used as a drive source for changing an operating position of a control object (11) to a target position of the electric motor (13) corresponding to a target operating position of the control object (11), the engine control device comprising: a limit position learning device for learning one of first and second limit positions of a movement range of the control object (11) corresponding to first and second rotational positions of the electric motor (13), respectively, by rotating the electric motor (13) to a corresponding one of the first and second rotational positions corresponding to one of the first and second limit positions of the movement range of the control object (11); a climb correction amount setting means for setting a climb correction amount for a learning value of one of the first and second limit positions learned by the limit position learning means, in order to correct the learning value of one of the first and second limit positions at the time of learning one of the first and second limit positions by the limit position learning means in view of a relatively small rotation angle of the electric motor (13) beyond the corresponding one of the first and second rotation positions following the rotation of the electric motor (13) to the corresponding one of the first and second rotation positions; a reference position learning means for learning a reference position by correcting the learning value of one of the first and second limit positions by the climb correction amount; a target position setting device for setting the target position of the electric motor (13) based on the reference position at the time of changing the operating position of the control object (11); and a motor temperature information determining means (36) for detecting or estimating motor temperature information which is one of a temperature of the electric motor (13) and a temperature related to the temperature of the electric motor (13), wherein the climb correction amount setting means sets the climb correction amount according to the motor temperature information. [2] The engine control apparatus according to claim 1, wherein the climb correction amount setting means sets the climb correction amount based on the engine temperature information and a power source voltage of the electric motor (13). [3] Engine control unit according to claim 1 or 2, wherein: the control object (11) is a range change mechanism (11) that changes a range of an automatic transmission (12) of a vehicle; and the engine temperature information determining means (36) detects an oil temperature of the automatic transmission (12) with an oil temperature sensor (36) and uses the detected oil temperature of the automatic transmission (12) as the engine temperature information. [4] Engine control unit with: a motor control device for controlling a rotational position of an electric motor (13) used as a drive source for changing an operating position of a control object (11) to a target position of the electric motor (13) corresponding to a target operating position of the control object (11); a reference position learning device for learning one of a first and a second limiting position of a movement range of the control object (11), which correspond to a first and a second rotational position of the electric motor (13), respectively, as a reference position by rotating the electric motor (13) to a corresponding one of the first and the second rotational position, which corresponds to the one of the first and the second limiting position of the movement range of the control object (11); a play amount learning device for learning a play amount in a rotation transmission system located between the electric motor (13) and the control object (11) by rotating the electric motor (13) to each of the first and second rotation positions; a target position setting means for setting the target position of the electric motor (13) with respect to a learning value of the play amount based on a learning value of the reference position learned by the reference position learning means at the time of changing the operating position of the control object (11); and a motor temperature information determining means (36) for detecting or estimating motor temperature information which is one of a temperature of the electric motor (13) and a temperature related to the temperature of the electric motor (13), wherein the backlash amount learning means executes the learning of the backlash amount when at least one learning execution condition is satisfied, which includes a falling of the temperature indicated by the motor temperature information within a predetermined temperature range. [5] Engine control unit according to claim 4, wherein: the reference position learning device learns the reference position immediately after switching on a power source of the engine control unit; and the target position setting means sets the target position of the electric motor (13) based on the learning value of the reference position by using a standard value of the play amount instead of the learning value of the play amount before completion of the learning of the play amount by the play amount learning means. [6] Engine control unit according to claim 4, wherein: the reference position learning device learns the reference position immediately after switching on a power source of the engine control unit; the target position setting means sets the target position of the electric motor (13) based on the learning value of the reference position without using the learning value of the play amount before completion of the learning of the play amount by the play amount learning means; and the motor control device executes an overshoot control operation at the time of changing the operating position of the control object (11) so that the electric motor (13) is rotated beyond the target position and is then rotated back.

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