JP2015001262A - Shift-by-wire control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shift-by-wire control device which can extremely suppress that an adverse effect is exerted to the control of an electric motor even if noise is superimposed on an output of an encoder.SOLUTION: A shift-by-wire control device determines whether or not noise is superimposed on an encoder signal from an encoder 31. Then, when it is determined that the noise is superimposed on the encoder signal, control processing such as positioning control and motor control for range switching based on the encoder signal which is performed by a microcomputer 21 of a range ECU 20 is stopped. Therefore, for example, when an electric motor 30 is driven to an erroneously rotation position different from a target position, and when performing the positioning control of the electric motor 30, a situation that the positioning control cannot be properly performed can be prevented.

Description

  The present invention relates to a shift-by-wire control device that electrically controls range switching of a range switching mechanism mounted on a vehicle.

  In recent years, in vehicles such as automobiles, there is an increasing tendency to change a mechanical drive system to an electric drive system in order to satisfy demands for space saving, improved assembly, and improved controllability. As an example, there is a shift-by-wire control device that electrically controls range switching of an automatic transmission using an electric motor.

  An example of such a shift-by-wire control device is disclosed in Patent Document 1. In the control device of Patent Document 1, a target rotational position of an electric motor for realizing a target range according to a shift command is set. Then, the electric motor is driven to rotate so that the count value of the output from the encoder that outputs the pulse signal in synchronization with the rotation of the electric motor is within a predetermined range with respect to the target count value corresponding to the target rotation position. By doing so, the range is switched electrically. When the electric motor is rotationally driven, the electric motor can be smoothly rotated by switching the energized phase of the electric motor in accordance with a signal from the encoder.

JP 2004-23890 A

  As described above, when the energized phase of the electric motor is switched based on the output from the encoder, or when the rotation position of the electric motor is controlled to the target position, noise is superimposed on the output from the encoder It is predicted that various problems will occur.

  For example, by erroneously recognizing the rotation position of the electric motor due to noise, it is erroneously determined that the target rotation position has been reached, or the timing for switching the energized phase of the electric motor is erroneously driven to drive the electric motor smoothly. There is a risk that it may become impossible.

  Moreover, in the control apparatus of patent document 1, the output from an encoder is taken in into a control apparatus by interruption processing, and the rotation position and rotation direction of an electric motor are calculated. Therefore, when noise is superimposed on the encoder output, the execution frequency of interrupt processing increases, and the execution frequency of other control processing decreases. As a result, there is a possibility of hindering smooth driving of the electric motor.

  Furthermore, in the control device described above, it is conceivable to execute electric motor positioning control in order to make the output count value of the encoder correspond to the rotational position of the electric motor. This positioning control can be executed as follows, for example. First, the electric motor is driven so as to rotate in a predetermined direction. Then, the output shaft of the electric motor (a member attached thereto) eventually comes into contact with the stopper wall set at the end of the movable range and stops. In this case, the output of the encoder does not occur despite the energization for driving the electric motor. Therefore, it can be considered that the output shaft of the electric motor is in contact with the stopper wall. In this way, since the rotational position of the electric motor can be determined, it is possible to correctly associate with the output count value of the encoder.

  However, when noise is superimposed on the output of the encoder during the positioning control described above, the output of the encoder continues to be generated even if the output shaft of the electric motor abuts against the stopper wall. In this case, for example, even if a predetermined time elapses, it may be erroneously determined that the output shaft of the electric motor does not contact the stopper wall, and it may be erroneously detected that some abnormality has occurred in the actuator including the electric motor.

  The present invention has been made in view of the above-described points, and provides a shift-by-wire control device that can suppress adverse effects on the control of an electric motor as much as possible even when noise is superimposed on the output of an encoder. The purpose is to do.

In order to achieve the above-described object, a shift-by-wire control device according to the present invention provides:
An electric motor (30) for switching the range by driving the range switching mechanism (40) of the vehicle by rotating the output shaft (32);
An encoder (31) that outputs a signal each time the electric motor rotates by a predetermined angle;
Drive control means (20) for driving the electric motor to a target rotational position based on the output of the encoder so that the range is switched in accordance with a shift command given from outside;
Noise determination means (S200, S220) for determining whether noise is superimposed on the output of the encoder,
The drive control means stops the control processing based on the output of the encoder when the noise determination means determines that noise is superimposed on the output of the encoder.

  Thus, in the present invention, when it is determined that noise is superimposed on the output of the encoder, the control process based on the output of the encoder in the drive control unit is stopped. For this reason, for example, when the electric motor is driven to an erroneous rotational position different from the target rotational position, or when positioning control of the electric motor is performed, a situation in which the electric motor cannot be properly positioned may be caused. Can be prevented. Furthermore, when noise is superimposed on the encoder output, an increase in the processing load of the drive control unit can be suppressed by stopping the interrupt process for capturing the encoder output. Therefore, even if noise is superimposed on the output of the encoder, it is possible to suppress the adverse effect on the control of the electric motor as much as possible.

  Note that the reference numerals in the parentheses merely show an example of a correspondence relationship with a specific configuration in an embodiment described later in order to facilitate understanding of the present invention, and limit the scope of the present invention. It is not intended.

  Further, the features of the present invention other than the features described above will be apparent from the description of embodiments and the accompanying drawings described later.

It is a block diagram which shows the schematic structure of the shift-by-wire control apparatus by embodiment. It is a wave form diagram which shows the relationship between the two-phase pulse signal from an encoder, and the switching time of an energized phase. It is a wave form diagram for demonstrating the basic control by a shift-by-wire control apparatus. It is explanatory drawing for demonstrating the malfunction which arises when noise is superimposed on an encoder signal. It is a flowchart which shows the interruption process performed when an encoder signal is input into a microcomputer. It is a flowchart which shows the process which the microcomputer in 1st Embodiment performs. It is a flowchart which shows the process which the microcomputer in 2nd Embodiment performs. It is a flowchart which shows the process which the microcomputer in 3rd Embodiment performs. It is a flowchart which shows the process which the microcomputer in 4th Embodiment performs. It is a flowchart which shows the process which the microcomputer in 5th Embodiment performs. It is a flowchart which shows the process which the microcomputer in 6th Embodiment performs.

(First embodiment)
Hereinafter, a shift-by-wire control device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating a schematic configuration of the shift-by-wire control device according to the present embodiment.

  As shown in FIG. 1, the shift-by-wire control device mainly includes a range determination device 10, a range electronic control device (hereinafter referred to as range ECU) 20, an electric motor 30, an automatic transmission 40, and the like. In the present embodiment, the shift-by-wire control device drives the range switching mechanism provided in the automatic transmission 4 with the electric motor 30, and the parking range (hereinafter referred to as P range) and other ranges other than the parking range. An example of switching between (hereinafter, non-P range) will be described.

  The range determination device 10 obtains shift position information as a result of a shift operation by a vehicle driver from a detection signal of a shift position sensor (not shown), and determines a target range based on the shift position information. The range determination device 10 may consider vehicle speed information and brake operation information in addition to the detection result by the shift position sensor when determining the target range. Then, the range determination device 10 makes a request for switching to the P range or a request for releasing the P range (a request for switching to the non-P range) to the range ECU 20 according to the determined target range.

  The shift position sensor described above detects an operation state of a shift operation unit (such as a shift lever or a shift lever and a parking switch) provided in the vehicle interior of the vehicle, and outputs the operation state to the range determination device 10.

  Based on the range switching request from the range determination device 10, the range ECU 20 executes range switching control. When the range switching is completed, the range ECU 20 transmits a range switching response to the range determination device 10. When the range determination device 10 does not receive a range switching response within a predetermined time from transmission of the range switching request, some abnormality has occurred in the range ECU 20, the range switching mechanism for performing range switching, the electric motor 30, or the like. Consider it a thing. In this case, for example, the range determination device 10 displays a warning light provided on the instrument panel of the vehicle, and notifies the vehicle driver that an abnormality has occurred regarding the range switching.

  The range ECU 20 mainly includes a microcomputer 21, a driver 22, input circuits 23 and 24, and a timer 25. The microcomputer 21 takes in the encoder signal output from the encoder 31 in synchronization with the rotation of the electric motor 30 via the input circuit 23 and counts the encoder signal. Based on the count value of the encoder signal, the actual rotational position of the electric motor 30 (that is, the actual range position of the automatic transmission 40) is detected.

  Further, the microcomputer 21 takes in the detection signal from the position sensor 41 that detects the P range position and the non-P range position of the automatic transmission 40 via the input circuit 24. The position sensor 41 is a first position sensor that outputs an ON signal when the range of the automatic transmission 40 becomes the P range, for example, like a neutral switch, and outputs an ON signal when the range becomes the non-P range. It consists of a second position sensor. With such a position sensor 41, the microcomputer 21 can detect whether the range of the automatic transmission 40 is the P range or the non-P range. Alternatively, the position sensor 41 may be, for example, a potentiometer that outputs a voltage corresponding to the rotation angle of the output shaft 32 of the speed reduction mechanism of the electric motor 30. In this case, the range of the automatic transmission 40 can be confirmed from the output voltage of the potentiometer.

  The microcomputer 21 is driven by the electric motor 30 via the driver 22 so that the range of the automatic transmission 40 is switched to the requested range based on the detection results from the encoder 31 and the position sensor 41 described above. Output a signal. The control executed for driving the motor by the microcomputer 21 of the range ECU 20 will be described in detail later.

  As will be described in detail later, the timer 25 is for counting a time that is expected to be required for the noise to disappear when it is determined that the noise is superimposed on the encoder signal from the encoder 31. is there.

  The electric motor 30 rotates in response to a drive signal from the range ECU 20, and for example, an SR (switched reluctance) motor can be adopted. This SR motor is also called a variable magnetoresistive motor, and does not require a permanent magnet or brush, and is a simple and inexpensive motor. In this electric motor 30, both the stator and the rotor have a salient pole structure (saliency pole portion). More specifically, the rotor of the electric motor 30 has a plurality of salient pole portions (for example, 8 pieces) protruding radially outward at equal intervals in the circumferential direction. On the other hand, the stator of the electric motor 13 has a plurality of salient pole portions (for example, 12 pieces) protruding radially inward at equal intervals in the circumferential direction. And with rotation of a rotor, each salient pole part of a rotor opposes each salient pole part of a stator in order via a micro gap. In addition, U-phase, V-phase, and W-phase windings forming energized phases are wound around the salient pole portion of the stator in order. The rotor is rotationally driven by appropriately switching the energized phase according to the rotation of the rotor. Needless to say, the number of salient pole structures of the stator and the rotor may be appropriately changed.

  An encoder 31 for detecting the rotational position is attached to the electric motor 30. The encoder 31 includes two rotors attached to the rotation shaft of the electric motor 30 and a pulse signal generation unit that generates a pulse signal according to the rotation of each rotor. The two rotors and the pulse signal generation unit are arranged such that the phases of the pulse signals generated by the rotation of the respective rotors are shifted by a predetermined phase. For example, if the pulse signal generated by the rotation of one rotor is the A phase and the pulse signal generated by the rotation of the other rotor is the B phase, the pulse signals of the A phase and the B phase as shown in FIG. Is shifted in phase by the switching time of the energized phase of the electric motor 30. Further, the A-phase and B-phase pulse signals have rising edges and falling edges at the timing of switching the energization phases of the electric motor 30 (U phase, V phase, W phase). Is set.

  Therefore, the electric motor 30 is rotated by counting both rising and falling edges of the A-phase pulse signal and the B-phase pulse signal and switching the energized phase of the electric motor 30 according to the count value. It can be driven.

At this time, according to the generation order of the A-phase pulse signal and the B-phase pulse signal, the microcomputer 21
The rotation direction of the electric motor 30 can be determined. The microcomputer 21 counts up the count value of the encoder signal in the normal rotation (P range → non-P range rotation direction), and counts the encoder signal in the reverse rotation (non-P range → P range rotation direction). Count down the value. Thereby, even if the electric motor 30 rotates in either the forward rotation direction or the reverse rotation direction, the correspondence between the count value of the encoder signal and the rotation position of the electric motor 30 can be maintained.

  In the example shown in FIG. 2, one-phase energization and two-phase energization are alternately switched when the energized phase is switched. That is, in the example of FIG. 2, the energized phases are switched in the order of W phase energization → UW phase energization → U phase energization → UV phase energization → V phase energization → VW phase energization. However, the energization method may be only one-phase energization or only two-phase energization.

  The rotating shaft of the electric motor 30 is connected to a speed reduction mechanism (not shown), and the output shaft 32 of the speed reduction mechanism is connected to a range switching mechanism provided in the automatic transmission 40. When the electric motor 30 rotates in one direction, the range switching mechanism is driven so that the range of the automatic transmission 40 is switched from the P range to the non-P range. Conversely, when the electric motor 30 rotates in the other direction, the range switching mechanism is driven so that the non-P range is switched to the P range.

  Thus, the output shaft 32 and the members of the range switching mechanism attached to the output shaft 32 move at least between a position corresponding to the P range and a position corresponding to the non-P range. Actually, the movable range is determined by the non-P-side stopper wall 33 provided at a position slightly beyond the non-P range position and the P-side stopper wall 34 provided at a position slightly beyond the P range position. It is prescribed.

  As the range switching mechanism provided in the automatic transmission 40, one disclosed in Japanese Patent Application Laid-Open No. 2004-23890 filed by the present applicant can be adopted. Therefore, the detailed description of the range switching mechanism is omitted.

  Further, the power source 50 in FIG. 1 is, for example, a gasoline engine, and the power generated by the gasoline engine is transmitted to the drive shaft of the vehicle via the automatic transmission 40.

  The basic control executed by the shift-by-wire control device configured as described above will be described with reference to the waveform diagram of FIG.

  For example, when the power is turned on from the power-off state, FIG. 3 shows how the motor is started. When the motor is started, since the rotational position of the electric motor 30 (shift position of the automatic transmission 40) is indefinite, the microcomputer 21 of the range ECU 20 first enters the positioning control mode and executes positioning control.

  In this positioning control, the electric motor 30 is driven in a direction in which the output shaft 32 of the electric motor 30 faces the P-side stopper wall 34. In addition, the drive of the electric motor 30 at this time is performed by switching an energized phase in order at predetermined time intervals from a predetermined energized phase. In this way, the electric motor 30 can be driven in the P range direction regardless of the rotational position of the electric motor 30. When the encoder signal is not output from the encoder 31 even though the electric motor 30 is driven, it is considered that the output shaft 32 of the electric motor 30 is in contact with the P-side stopper wall 34. Can do.

  Thus, when it can be confirmed that the output shaft 32 of the electric motor 30 has come into contact with the P-side stopper wall 34, the absolute position of the output shaft 32 of the electric motor 30 in the rotational direction is determined. Therefore, it is possible to associate the count value of the encoder signal with the rotational position of the electric motor 30 using the absolute position as a reference.

  When the above-described positioning control is completed, the microcomputer 21 once stops driving the electric motor 30 as shown in FIG. At the same time, the microcomputer 21 shifts to the normal control mode. In the normal control mode, the control of the electric motor 30 is kept off until a range switching request is issued from the range determination device 10, and a standby state is entered. However, an encoder signal is output from the encoder 31 when the electric motor 30 oscillates and rotates despite the fact that the drive is stopped due to vibration of the vehicle body, for example. Even in the standby state, when an encoder signal is output from the encoder 31, the encoder signal is counted. Thereby, the count position of the encoder signal is updated so as to indicate the actual rotational position of the electric motor 30.

  When a range switching request is issued from the range determination device 10, range switching control is executed. In this range switching control, the rotational position of the electric motor 30 corresponding to the requested range is determined as a target count value. Then, the electric motor 30 is driven in the direction of the required range so that the count value of the encoder signal is within a predetermined range with respect to the target count value. As described above, the electric motor 30 is driven by switching the energized phase each time an encoder signal is output.

  Here, as described above, when positioning control is performed based on the encoder signal from the encoder 31, the energized phase is switched, or the rotational position of the electric motor 30 is controlled to the target position. When noise is superimposed on the encoder signal, various problems are expected to occur.

  For example, as shown in FIG. 4, when noise is superimposed on the encoder signal in the normal control mode, the count value of the encoder signal changes even though the electric motor 30 is not actually rotating, The rotational position indicated by the count value deviates from the actual rotational position. As a result, when the electric motor 30 is driven in response to the range switching request, there is a possibility that it is erroneously determined that the target rotational position has been reached. Moreover, there is a possibility that the electric motor 30 cannot be smoothly driven by erroneously switching the energized phase of the electric motor 30 due to noise.

  Further, when noise is superimposed on the encoder signal during positioning control, the encoder signal continues to be generated even if the output shaft 32 of the electric motor 30 abuts against the P-side stopper wall 34. In this case, it is erroneously determined that the output shaft 32 of the electric motor 30 does not contact the P-side stopper wall 34 even after a predetermined time has elapsed. As a result, for example, the range determination device 10 may erroneously determine that some abnormality has occurred in the actuator including the electric motor 30 based on not receiving a positioning completion response within a predetermined time from the start.

  Therefore, the shift-by-wire control device according to the present embodiment determines whether noise is superimposed on the encoder signal from the encoder 31. If it is determined that noise is superimposed on the encoder signal, control processing such as positioning control and motor control for range switching based on the encoder signal executed by the microcomputer 21 of the range ECU 20 is stopped. I did it. For this reason, for example, when the electric motor 30 is driven to an incorrect rotational position different from the target position, or when positioning control of the electric motor 30 is performed, a situation in which the positioning cannot be performed properly is caused. This can be prevented.

  Hereinafter, an example of a control process executed by the microcomputer 21 of the range ECU 20 will be described with reference to the flowcharts of FIGS. 5 and 6.

  First, FIG. 5 is a flowchart showing an interrupt process executed when an encoder signal is input from the encoder 31 to the microcomputer 21. As described above, the encoder signal is taken in by the microcomputer 21 by interruption in order to prevent input leakage.

  In Step S100, the type (whether A phase or B phase) and change (rising edge or falling edge) of the acquired encoder signal are determined. In the subsequent step S110, the rotation direction is calculated based on the type and change of the encoder signal acquired last time and the type and change of the encoder signal acquired this time. Further, the count value indicating the rotational position of the electric motor 30 is calculated by increasing or decreasing the count value of the encoder signal according to the calculated rotation direction.

  FIG. 6 is a flowchart showing processing for the microcomputer 21 to perform the above-described positioning control and range switching control. The process shown in this flowchart is started when the microcomputer 21 is activated.

  First, in step S200, it is determined whether noise is superimposed on the encoder signal. In this determination process, for example, when the rotation speed of the electric motor 30 is calculated from the encoder signal captured by the interrupt process, and a rotation speed that cannot occur in normal drive control is calculated, noise is superimposed on the encoder signal. judge. Alternatively, it may be determined whether or not noise is superimposed on the encoder signal under the condition that the encoder signal interval is shorter than the predetermined interval or the number of encoder signals within a certain period is equal to or greater than a predetermined value.

  If it is determined in step S200 that no noise is superimposed on the encoder signal, positioning control is executed in step S210. However, if it is determined that noise is superimposed on the encoder signal, the process of step S200 is continued. That is, the positioning control is not executed unless it is determined that noise is not superimposed. For this reason, it is possible to avoid a situation in which positioning control cannot be performed properly due to the influence of noise superimposed on the encoder signal.

  As described above, when the positioning control is completed, the process shifts to the normal control mode. In this normal control mode, the process waits until a range switching request is output from the range determination device 10. Since it is conceivable that noise is superimposed on the encoder signal during the standby, in step S220, whether or not noise is superimposed on the encoder signal is determined in the same manner as in step S200. At this time, if it is determined that noise is superimposed on the encoder signal, the process returns to step S200. When noise is superimposed on the encoder signal, the rotational position indicated by the count value of the encoder signal may deviate from the actual rotational position. Therefore, returning to the process of step S200, when the noise disappears, the positioning control is executed again in step S210.

  If it is determined in step S220 that no noise is superimposed on the encoder signal, it is determined in step S230 whether or not a range switching request has been issued from the range determination device 10. If it is determined that a range switching request has not been issued, the process returns to step S220. On the other hand, if it is determined that a range switching request has been issued, the process proceeds to step S240 to execute range switching control. In step S250, it is determined whether or not the ignition switch is turned off. If it is not turned off, the process returns to step S220. If it is turned off, the process shown in the flowchart of FIG. 6 is terminated.

(Second Embodiment)
Next, a shift-by-wire control device according to a second embodiment of the present invention will be described. Note that the shift-by-wire control device according to the present embodiment is configured in the same manner as the shift-by-wire control device according to the first embodiment described above, and thus description of the configuration is omitted.

  However, in this embodiment, the microcomputer 21 of the range ECU 20 is configured to hold the shift switching request output from the range determination device 10 in its own memory. In this way, for example, when a shift switching request is received when noise is superimposed on the encoder signal and the range switching control is stopped, the request can be held in the memory. For this reason, the range determination device 10 can immediately switch to the requested range when noise disappears without continuing to output the range switching request.

  The flowchart of FIG. 7 shows a control process executed by the microcomputer 21 of the range ECU 20 in the present embodiment. The process shown in this flowchart is started when the microcomputer 21 is activated.

  First, in step S300, as in step S200 in the flowchart of FIG. 6, it is determined whether noise is superimposed on the encoder signal. If it is determined that no noise is superimposed on the encoder signal, the process proceeds to step S310. In step S310, it is determined whether a range switching request is stored. If it is determined that the range switching request is stored, the process proceeds to step S320. If it is determined that the range switch request is not stored, the process proceeds to step S340.

  In step S320, the range switching direction according to the stored range switching request is determined. That is, when the range switching request requests switching to the non-P range, the direction of the non-P range is determined as the switching direction, and when switching to the P range is requested, the P range is determined. Is determined as the switching direction. If it is determined that the switching direction is the non-P range direction, the process proceeds to step S330. If the switching direction is determined to be the P range direction, the process proceeds to step S340.

  In step S330, positioning control is executed using the non-P-side stopper wall 33. On the other hand, in step S340, positioning control is executed using the P-side stopper wall 34. For example, when noise is superimposed on the encoder signal during the normal control mode, it is necessary to associate the count value of the encoder signal with the actual rotational position, so that positioning control is executed again. At that time, when the range switching request issued from the range determination device 10 is stored and held by the above-described processing, positioning control is performed using a stopper wall close to the requested range. . Thereby, it becomes possible to drive the electric motor 30 earlier to the position corresponding to the required range after the positioning control.

  In addition, when the range switching request from the range determination device 10 is not stored and held, for example, at the time of activation, for example, since the process of step S340 is performed, the P-side stopper wall 34 is set as in the first embodiment. Positioning control is performed using this.

  When the positioning control is completed, the process shifts to the normal control mode, and in step S350, it is determined whether noise is superimposed on the encoder signal as in step S220 of the flowchart of FIG. At this time, if it is determined that noise is superimposed on the encoder signal, the process returns to step S300. On the other hand, if it is determined that no noise is superimposed on the encoder signal, it is determined in step S360 whether a range switching request is stored. If it is determined that the range switching request is stored, the process proceeds to step S370, and range switching control is executed. In the subsequent step S380, since the range switching control based on the stored range switching request is completed, the stored switching request is cleared.

  In step S390, it is determined whether or not the ignition switch is turned off. If it is not turned off, the process returns to step S350. If it is turned off, the process shown in the flowchart of FIG. 7 is terminated.

(Third embodiment)
Next, a shift-by-wire control device according to a third embodiment of the present invention will be described. Note that the shift-by-wire control device according to the present embodiment is configured in the same manner as the shift-by-wire control device according to the first embodiment described above, and thus description of the configuration is omitted.

  However, in the present embodiment, the microcomputer 21 of the range ECU 20 is configured to hold the reset history in its own memory when the range ECU 20 is reset.

  As described in the first embodiment, the encoder signal is taken into the microcomputer 21 of the range ECU 20 by interrupt processing, and the count value indicating the rotation direction and the rotation position of the electric motor 30 is calculated. For this reason, when noise is superimposed on the encoder signal, the execution frequency of interrupt processing increases, and the execution frequency of other control processing decreases. In particular, when the frequency of execution of interrupt processing is high, the processing capability of the microcomputer 21 cannot catch up with the interrupt processing request, and it seems as if the microcomputer 21 has been frozen. In this case, since the microcomputer 21 does not operate normally, the range ECU 20 is reset.

  However, when the range ECU 20 is restarted by resetting, if noise in the encoder signal still remains, the operation of the microcomputer 21 is not performed normally, and there is a high possibility that it will be reset again. The purpose of this embodiment is to prevent such a continuous reset.

  The flowchart of FIG. 8 shows a control process executed by the microcomputer 21 of the range ECU 20 in the present embodiment. The process shown in this flowchart is started when the microcomputer 21 is activated.

  First, in step S400, it is determined whether or not the range ECU 20 has been reset with reference to the reset history held in its own memory. If it is determined that the reset has been performed, the reset history is cleared in step S410, and then the interrupt process of the encoder signal is prohibited in step S420. In step S410, the reason for clearing the reset history is that the prohibition of the interrupt process of the encoder signal is limited to the first activation from the reset. Then, by prohibiting encoder signal interruption processing in this way, it is possible to prevent the range ECU 20 from being continuously reset.

  In the subsequent step S430, the process waits for a predetermined time when noise is expected to disappear. This predetermined time is determined experimentally. In step S440, the encoder signal interrupt process is permitted, and the process returns to step S400.

  Note that the processing from step S450 to S500 is basically the same as the processing from step S200 to S250 in the flowchart of FIG. However, the difference is that when it is determined in step S450 or S470 that noise is superimposed on the encoder signal, interrupt processing of the encoder signal is prohibited for a predetermined time. By doing so, it is possible to prevent the microcomputer 21 from operating normally or the range ECU 20 from being reset when noise is superimposed on the encoder signal.

(Fourth embodiment)
Next, a shift-by-wire control device according to a fourth embodiment of the present invention will be described. Note that the shift-by-wire control device according to the present embodiment is configured in the same manner as the shift-by-wire control device according to the first embodiment described above, and thus description of the configuration is omitted.

  In this embodiment, since noise is superimposed on the encoder signal, the above-described positioning control and range switching control are not executed, and when the noise is waiting to disappear, the range determination device 10 cannot currently perform range switching. Is to be notified. As a result, in the range determination device 10, it is erroneously assumed that some abnormality has occurred in the range ECU 20, the range switching mechanism for performing range switching, or the electric motor 30 based on the fact that the range switching response cannot be received within a predetermined time from the range switching request. Can be prevented.

  Therefore, the microcomputer 21 of the range ECU 20 in the present embodiment executes the processing shown in the flowchart of FIG. The processing in steps S600 to S650 in the flowchart in FIG. 9 is the same as the processing in steps S200 to S250 in the flowchart in FIG. However, if it is determined in step S600 or S620 that noise is superimposed on the encoder signal, the process of step S660 is executed. In the process of step S660, the range determination apparatus 10 is notified that the range cannot be switched due to the influence of noise.

(Fifth embodiment)
Next, a shift-by-wire control device according to a fifth embodiment of the present invention will be described. Note that the shift-by-wire control device according to the present embodiment is configured in the same manner as the shift-by-wire control device according to the first embodiment described above, and thus description of the configuration is omitted.

  In the first embodiment described above, if it is determined that noise is superimposed on the encoder signal, the positioning control and the range switching control are not executed, and the electric motor 30 is prevented from being driven to an incorrect position. In the present embodiment, in order to more reliably prevent the electric motor 30 from being erroneously operated, when it is determined that noise is superimposed on the encoder signal, the electric motor 30 generates a driving force for rotating. It was banned.

  Therefore, the microcomputer 21 of the range ECU 20 in the present embodiment executes the process shown in the flowchart of FIG. The processes of steps S700 and S720 to S760 in the flowchart of FIG. 10 are the same as the processes of steps S200 to S250 in the flowchart of FIG. However, if it is determined in step S700 or S730 that noise is superimposed on the encoder signal, the process of step S770 is executed. In the process of step S770, generation of the driving force of the electric motor 30 is prohibited. For example, the microcomputer 21 prohibits the generation of the driving force of the electric motor 30 by prohibiting the output of the driving signal to the electric motor 30 or turning off the relay inserted in the power supply line of the electric motor 30. be able to.

  If it is determined in step S700 that noise is not superimposed on the encoder signal, generation of the driving force of the electric motor 30 is permitted in step S710. As a result, thereafter, positioning control and range switching control can be executed using the electric motor 30.

(Sixth embodiment)
Next, a shift-by-wire control device according to a sixth embodiment of the present invention will be described. Note that the shift-by-wire control device according to the present embodiment is configured in the same manner as the shift-by-wire control device according to the first embodiment described above, and thus description of the configuration is omitted.

  The shift-by-wire control device according to the present embodiment does not stop the range switching control at that time when noise is superimposed on the encoder signal from the encoder 31, but does not stop the range switching control based on the detection signal of the position sensor 41. Is to be executed.

  The flowchart of FIG. 11 shows processing executed by the microcomputer 21 of the range ECU 20 in the present embodiment. First, in step S800, it is determined whether noise is superimposed on the encoder signal. If it is determined that noise is not superimposed, the process proceeds to step S810, and the rotational position of the electric motor 30 is feedback-controlled based on the count value of the encoder signal. Specifically, in step S810, the target count value determined according to the requested range is compared with the count value of the encoder signal indicating the actual rotational position, and it is determined whether or not both values match. Is done. If it is determined that they do not match, the electric motor 30 is energized in step S820 so that the count value of the encoder signal approaches the target count value.

  On the other hand, if it is determined in step S800 that noise is superimposed on the encoder signal, the process proceeds to step S830, and the range position is detected from the detection signal of the position sensor 41. In subsequent step S840, it is determined whether or not the detected range position matches the target range position. If it is determined that they do not match, the electric motor 30 is energized in step S850. However, in this case, the electric motor 30 is rotationally driven by outputting a drive signal of a predetermined pattern determined in advance according to the range position detected by the position sensor 41 and the target range position to the electric motor 30. . That is, when the electric motor 30 is rotationally driven based on the detection signal of the position sensor 41, open loop control is performed with a predetermined pattern of drive signals. This is because the position sensor 41 does not have the resolution and accuracy as high as those of the encoder 31.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, the above-described shift-by-wire control devices from the first embodiment to the fifth embodiment may be implemented independently, but may be implemented in any combination.

  Further, in the above-described embodiment, the example in which the shift-by-wire control device switches the range between the P range and the non-P range by driving the range switching mechanism provided in the automatic transmission 40 has been described. However, the present invention can also be applied to a range switching device that switches each range of P 1, R 2, N 2, D 3,... Of the automatic transmission in conjunction with the rotation operation of the output shaft 32 of the electric motor 30. .

  Furthermore, in the case of a hybrid vehicle in which a generator, an engine, and an electric motor (output shaft) are connected via a planetary gear mechanism, the automatic transmission as in the above-described embodiment is not provided, but the P range and A range switching mechanism for switching to the non-P range is provided. In other words, the range switching mechanism includes a lock pin, and when the lock pin is engaged with the output shaft, the output shaft is in a P range where rotation of the output shaft is prohibited. When the engagement is released, the output shaft rotates. Allowed non-P range. The shift-by-wire control device of the present invention may be applied to driving such a range switching mechanism.

10 Range determination device 20 Range ECU
30 Electric motor 31 Encoder 40 Automatic transmission 41 Position sensor

Claims (10)

An electric motor (30) for switching the range by driving the range switching mechanism (40) of the vehicle by rotating the output shaft (32);
An encoder (31) that outputs a signal each time the electric motor rotates by a predetermined angle;
Drive control means (20) for driving the electric motor to a target rotational position based on the output of the encoder so that the range is switched according to a shift command given from the outside;
Noise determination means (S200S220) for determining whether noise is superimposed on the output of the encoder;
The drive control unit stops a control process based on the output of the encoder when the noise determination unit determines that noise is superimposed on the output of the encoder.   As a control process based on the output of the encoder, the drive control means rotationally drives the electric motor in a predetermined direction at startup, and the output shaft of the electric motor comes into contact with a stopper wall existing in the predetermined direction. 2. The shift-by-wire control device according to claim 1, wherein the rotation control of the electric motor is continued until the electric motor stops rotating and no signal is output from the encoder. .   The drive control means executes, as the control process based on the output of the encoder, range switching control for driving the motor to a target rotational position based on the output of the encoder after the positioning control. The shift-by-wire control device according to claim 2.   The drive control means, as a control process based on the output of the encoder, when a signal is output from the encoder, performs a process of calculating the rotational position of the electric motor by capturing the signal by interruption. A shift-by-wire control device according to any one of claims 1 to 3. The drive control means is constituted by an electronic control device,
The electronic control device is to be reset and restarted when an abnormality occurs, and has a storage means for storing that when the reset is applied,
When the electronic control device is activated, if the storage means stores that the reset has been applied, the drive control means assigns a signal from the encoder without waiting for the determination by the noise determination means. The shift-by-wire control device according to claim 4, wherein the capturing process is stopped by loading. The electric motor is driven to one of a first rotational position for switching to the parking range and a second rotational position for switching to a range other than the parking range as the range switching. Yes,
A first stopper wall is provided corresponding to the first rotational position, and a second stopper wall is provided corresponding to the second rotational position;
Holding means for holding the shift command;
The drive control means outputs the output of the encoder by the noise determination means when driving the electric motor toward either the first rotational position or the second rotational position or during the driving. If it is determined that noise is superimposed, the electric motor is stopped, and after the noise has disappeared, the electric motor is used using a stopper wall corresponding to a rotational position corresponding to a shift command held in the holding means. 6. The range switching control for driving the electric motor is executed with the rotation position corresponding to the shift command as a target position, and positioning control for positioning the rotation position is executed. The shift-by-wire control device according to any one of the above.   When the control process based on the output of the encoder is stopped by the stop means, the shift command output unit that outputs the shift command indicates that the electric motor cannot be driven to a target rotational position. The shift-by-wire control device according to claim 1, further comprising notification means for notifying the device.   8. The apparatus according to claim 1, further comprising: a stop unit that stops generation of a rotational driving force by the electric motor when the control unit based on the output of the encoder is stopped by the stop unit. Shift-by-wire control device. A position sensor that detects which range the rotational position of the electric motor belongs to;
The drive control means is based on the detection result of the position sensor from the rotational position control of the electric motor based on the output of the encoder when the noise determination means determines that noise is superimposed on the output of the encoder. The shift-by-wire control device according to claim 1, wherein the shift-by-wire control device is switched to rotational position control of the electric motor.   The rotational position control of the electric motor based on the detection result of the position sensor is based on the detection result of the range to which the rotational position of the electric motor belongs by the position sensor. The shift-by-wire control device according to claim 9, wherein the shift-by-wire control device is executed by outputting a drive signal to the electric motor.

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