JP2008029174A - Current control device and method for actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurate current control of an actuator at any temperature of the operation environment of the current control device for the actuator. <P>SOLUTION: The internal temperature of the current control device for the actuator is detected and a correction corresponding to the internal temperature is performed relative to the current value of the actuator detected by a current detection circuit. The output voltage value to the actuator is feedback controlled based on the difference between the corrected current detection value and the target current value to the actuator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an actuator current control apparatus and method for controlling an actuator such as a linear solenoid whose operating temperature environment is wide, such as a control apparatus installed inside an automatic transmission.

  Conventionally, current control that detects the current that flows through the linear solenoid that adjusts the hydraulic pressure supplied to the friction engagement element of the automatic transmission, and feedback-controls the energization current to the linear solenoid so that the detected current value matches the target value. The device is well known. In such a current control device, several improvement measures have been proposed in order to further improve the control performance.

  For example, in Patent Document 1, even if the resistance value changes depending on the operating environment temperature of the linear solenoid, the output value of the linear solenoid is calculated by calculating the resistance value and correcting the energization amount according to the result. It has been proposed to prevent the change from occurring.

  Further, in Patent Document 2, in addition to compensating for the temperature change of the linear solenoid resistance value in the same manner as in Patent Document 1, the detection error due to the variation of the resistor itself of the current detection circuit is corrected differently for each current detection circuit. A technique for canceling is disclosed.

Japanese Patent Laid-Open No. 9-280411 JP 2003-111487 A

  By the way, in the control apparatus of a vehicle, the example installed in the inside or vicinity of a control object has recently increased. For example, when a control device is installed in or near the automatic transmission, the control device is easily affected by heat from the automatic transmission. Since the transmission itself is extremely hot, the temperature of the control device itself is also extremely high. On the other hand, when the vehicle is started in a cold region, the temperature of the control device remains low because the automatic transmission itself is not in a heated state. As described above, the control device installed in or near the controlled object often has a wide operating temperature range.

  Changes in the operating temperature of the control device affect circuit elements within the control device. For example, in the feedback control system of the linear solenoid as disclosed in Patent Document 1 and Patent Document 2, not only the resistance value of the linear solenoid but also the resistance value in the current detection circuit varies depending on the temperature. For this reason, even if the current flowing through the linear solenoid is the same value, if the operating temperature of the control device is different, the detected current value by the current detection circuit is different, and the detected current value does not match the actual value. Therefore, if feedback control is performed based on the detected current value, a current different from the target current value continues to flow through the linear solenoid. As a result, the state in which the hydraulic pressure supplied to the frictional engagement element is different from the desired value continues, and adverse effects such as a shift shock and wear of the frictional engagement element are caused.

  The present invention provides a current control device capable of suitably controlling the current of an actuator such as a linear solenoid even when the resistance value in the current detection circuit changes with temperature in a current control device having a wide operating temperature range. For the purpose.

  According to the present invention, the current flowing through the actuator is detected by the current detecting means, and in the current control of the actuator that performs feedback control so that the detected current value approaches the target current, the temperature in the vicinity of the current detecting means is detected. The current detection value is corrected according to the detected temperature.

  Thus, even if the resistance value of the current detection means changes due to a temperature change in the current control system, the correction value of the current detection value for each temperature stored in advance is read, and the actuator is based on the corrected current detection value. The energizing current is controlled by feedback.

  In a preferred embodiment of the present invention, a plurality of correction values respectively corresponding to a plurality of different temperature detection values are stored, and correction values corresponding to other different actual temperature detection values are stored in the plurality of stored correction values. Calculate by interpolation based on.

  Thus, when the actual temperature of the current control system does not correspond to any of the plurality of temperature conditions, a correction value that should correspond to the actual temperature detection value is obtained by interpolation calculation.

  In another preferred embodiment of the present invention, a plurality of correction values are stored for each combination of a plurality of different temperature detection values and a plurality of different target current values, and an actual temperature detection value and an actual temperature detection value are stored. According to a combination of target current values, the plurality of correction values are read to correct the current detection values.

  As a result, even if the temperature of the current control system is the same value, if the target current is different, if the resistance value of the current detection means is different, a correction value that also considers the target current for the actuator is read, and based on this The energizing current is controlled by feedback.

  Also in this case, it is desirable to calculate a correction value corresponding to the actual temperature detection value and the actual target current value by interpolation based on a plurality of stored correction values.

  Further, in a preferred embodiment of the present invention, the oil temperature of the hydraulic oil of the vehicle automatic transmission is detected by an oil temperature sensor, and the automatic or automatic control in the vicinity of or inside the vehicle automatic transmission is based on the detected oil temperature. The temperature of the transmission control device is estimated and used as the temperature detection value.

  As a result, since the current control system is installed in the vicinity or inside of the vehicle automatic transmission, the oil temperature sensor assumes that the internal temperature of the current control device correlates with the oil temperature of the hydraulic oil of the automatic transmission. The internal temperature of the current control system is estimated from the temperature of the hydraulic oil detected from

  According to the present invention, when the temperature of the current control system affects the detection of the current flowing through the actuator, the detection current is corrected using the correction value under the temperature condition, so that the accuracy is not affected by the temperature change. The current control of the actuator can be realized.

  According to a preferred embodiment of the present invention, the current detection value can be corrected with higher accuracy by calculating the correction value of the detection current corresponding to the actual temperature of the current control system by interpolation calculation.

  According to another preferred embodiment of the present invention, by correcting the current detection value in accordance with the combination of the temperature of the current control system and the target current, a highly accurate actuator that is not affected by changes in temperature can be obtained. Current control can be realized.

  Furthermore, in the current control system of an actuator installed near or in the automatic transmission, the current detection value is corrected without providing a dedicated sensor by estimating the temperature of the current control system using an oil temperature sensor. can do.

  Other objects and features of the present invention will become apparent from the following description of the embodiments.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an automatic transmission for a vehicle including an actuator current control device according to an embodiment of the present invention. The actuator in this embodiment is a linear solenoid.

  In FIG. 1, the output torque of an engine (not shown) mounted on a vehicle is transmitted to drive wheels (not shown) via an automatic transmission 1. The automatic transmission 1 controls the supply of operating hydraulic pressure to frictional engagement elements such as a clutch and a brake by a linear solenoid unit 3 including a plurality of linear solenoids 31 to 3n via a hydraulic pressure supply circuit 2. The current of the linear solenoid unit 3 is controlled by the automatic transmission control device 4, and the hydraulic pressure supply circuit 2, the linear solenoid unit 3 and the automatic transmission control device 4 are incorporated in the automatic transmission 1. The automatic transmission control device 4 does not necessarily need to be incorporated in the automatic transmission 1 and can be installed in the vicinity of the automatic transmission 1.

  Next, the internal configuration of the automatic transmission control device 4 will be described with reference to FIG.

  FIG. 2 is an internal configuration diagram of an automatic transmission control apparatus including an actuator current control apparatus according to an embodiment of the present invention. The automatic transmission control device 4 includes an input circuit 11, a microcomputer 12, an internal temperature sensor 13, a linear solenoid drive circuit 14, and a linear solenoid current detection circuit 15.

  The input circuit 11 inputs signals from an accelerator opening sensor 16, a turbine rotation sensor 17, a vehicle speed sensor 18, an AT oil temperature sensor 19, an inhibitor switch 20, a main power switch 21, and the like. Then, the waveform is shaped by removing noise components from these signals and the like, and output to the input terminal of the microcomputer 12.

  The microcomputer 12 includes a ROM 22, a RAM 23, a CPU 24, and the like. The CPU 24 executes a control program stored in the ROM 22 in response to signal inputs from the sensors 16 to 19 and the switches 20 and 21. Do. Further, the signal input after waveform shaping of each of the sensors 16 to 19 and the switches 20 and 21 is input by performing processing such as A / D conversion. The calculation result and information such as the signal input are temporarily stored in the RAM 23, and the calculation result is passed as a signal to the linear solenoid unit 3 (n linear solenoids 31 to 3n) via the linear solenoid drive circuit 14. Is output. Depending on the mechanism of the automatic transmission 1, there may be an actuator other than the linear solenoids 31 to 3n, but even in that case, the application of the present invention is not hindered.

  The linear solenoid unit 3 (31 to 3n) applies a predetermined hydraulic pressure to the hydraulic circuit in the transmission 1. By applying a predetermined hydraulic pressure to the hydraulic circuit in the transmission 1, a friction engagement element and a lockup mechanism in the transmission gear mechanism are operated, and a predetermined gear stage and lockup are realized. The internal temperature sensor 13 is a sensor that measures the internal temperature of the automatic transmission control device 4, and is mounted on the substrate of the automatic transmission control device 4.

  FIG. 3 is a schematic process flowchart of current control executed by the automatic transmission control device 4 according to one embodiment of the present invention. The contents of the current control shown below are stored as programs in the ROM 22 in the microcomputer 12 of the automatic transmission control device 4, and are repeatedly executed at a predetermined cycle.

  In FIG. 3, first, in step 301, vehicle running conditions such as the accelerator opening, the turbine speed, the vehicle speed, the AT oil temperature, the range position, and the like are detected from signals input by the sensors and the switches. Based on the vehicle running state, the target gear stage is set, and the target hydraulic pressure is set in each hydraulic circuit for operating each friction engagement element in step 302. Next, in step 303, conversion from the target hydraulic pressure to the target current that flows to the solenoid is performed. Next, in step 304, current feedback control is performed based on the target current. Details of the current feedback control will be described later in the description of the current control system of the linear solenoid in FIG. Based on the duty ratio calculated by the current feedback control, a PWM signal is output to each solenoid in step 305.

  Next, the current control system of the linear solenoid will be described with reference to FIG.

  FIG. 4 is a control block diagram of the current control system of the linear solenoid according to one embodiment of the present invention. First, the target hydraulic pressure in each friction engagement element and the lockup mechanism is converted into a target current, and a deviation between the target current and a detection current described later is calculated. Based on this deviation, the PID control unit 31 calculates a feedback correction current, adds the feedback correction current and the target current, and passes this addition result to the current-duty conversion unit 32 as an instruction current.

  The current-duty conversion unit 32 calculates a duty ratio corresponding to the indicated current, and outputs a duty signal corresponding to the PWM cycle to the linear solenoid drive circuit 14 based on the calculated value. The current flowing through the linear solenoid unit 3 is output as a detection voltage from a linear solenoid current detection circuit 15 including a current detection resistor and a differential amplifier circuit, and is converted into digital data by an A / D converter 33. This digital data is converted into a detection current by the voltage-current conversion unit 34 and delivered to the detection current correction unit 35.

  On the other hand, the internal temperature of the automatic transmission control device 4 is detected as a sensor voltage by the internal temperature sensor 13 and converted into digital data by the A / D converter 36. This digital data is converted into an internal temperature by the voltage-temperature conversion unit 37 and delivered to the detected current correction unit 35.

  Next, details of the detected current correction unit 35 will be described with reference to FIGS.

  FIG. 5 is a process flowchart of the detection current correction unit 35 in the current control system of the linear solenoid according to one embodiment of the present invention. In FIG. 5, first, in step 501, a correction value is calculated. Here, the correction value of the detected current will be described with reference to FIGS.

  FIG. 6 is a graph showing the contents of the correction value calculation table according to the internal temperature according to one embodiment of the present invention. As a calculation method of the correction value, for example, as shown in FIG. 6, there is a method of calculating the correction value by table search according to the internal temperature. That is, a value is set for each of a plurality of internal temperature conditions, and a correction value is calculated by interpolation calculation according to the actual internal temperature. If there is no problem in the accuracy of the value, interpolation calculation may not be performed.

  FIG. 7 is a correction value calculation table for each of a plurality of combination conditions of the internal temperature and the target current according to another embodiment of the present invention. As shown, a value is set for each of a plurality of combination conditions of a plurality of internal temperatures and target currents, and a correction value is calculated by a two-dimensional map search according to the actual internal temperature and target current. Interpolation calculation may be performed depending on the necessity of value accuracy.

  Using the correction values calculated as described above, the corrected detection current value is calculated by adding the detection current and the correction value in step 502 of FIG.

  As another method for calculating the correction value, there is a method using a correlation between the internal temperature and the correction value or a characteristic equation that approximates the correlation between the internal temperature and the target current and the correction value in a linear form. Even in such a case, there is no problem in applying the present invention. In this embodiment, after the detection voltage by the current detection circuit is converted into the detection current, correction according to the internal temperature and the target current is performed. However, even when the internal temperature and the target current are used as parameters in the conversion from the detection voltage to the detection current, there is no problem in applying the present invention.

  In addition, when the internal temperature sensor is not mounted on the current control device or when the internal temperature sensor fails, the oil temperature of the hydraulic oil of the automatic transmission detected by the oil temperature sensor is used as an alternative to the internal temperature. Alternatively, the detected temperature may be corrected by estimating the internal temperature using the oil temperature. Since a current control device is installed near or inside the automatic transmission, it is desirable to use this. Further, although the automatic transmission control device is used as an example of the current control device, the current control device may be a motor drive device and the actuator may be an inverter.

  The present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

1 is a schematic configuration diagram of an automatic transmission for a vehicle including an actuator current control device according to an embodiment of the present invention. The internal block diagram of the automatic transmission control apparatus containing the electric current control apparatus of the actuator by one Example of this invention. 4 is a schematic process flowchart of current control executed by the automatic transmission control device 4 according to an embodiment of the present invention. The control block diagram of the current control system of the linear solenoid by one Example of this invention. The processing flowchart of the detection current correction | amendment part in the current control system of the linear solenoid by one Example of this invention. The graph showing the content of the correction value calculation table according to the internal temperature by one Example of this invention. The correction value calculation table for every some combination conditions of internal temperature and target current by the other Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Automatic transmission, 2 ... Hydraulic supply circuit, 3 ... Linear solenoid unit, 31, 32,-3n ... Linear solenoid, 4 ... Automatic transmission control apparatus, 11 ... Input circuit, 12 ... Microcomputer, 13 ... Internal temperature Sensor: 14 ... Linear solenoid drive circuit, 15 ... Linear solenoid current detection circuit, 16 ... Accelerator opening sensor, 17 ... Turbine rotation sensor, 18 ... Vehicle speed sensor, 19 ... AT oil temperature sensor, 20 ... Inhibitor switch, 21 ... Main Power switch, 22 ... ROM, 23 ... RAM, 24 ... CPU.

Claims (10)

  In a current control device for an actuator comprising a current detection means for detecting a current flowing through the actuator and a current control system for feedback control so that a current detection value by the current detection means approaches a target current, in the vicinity of the current detection means An actuator current control device comprising: temperature detection means for detecting the temperature of the current; and current detection value correction means for correcting the current detection value according to a temperature detection value by the temperature detection means.   2. The current detection value correction unit according to claim 1, wherein the current detection value correction unit stores a plurality of correction values respectively corresponding to a plurality of different temperature detection values, and a correction value corresponding to another different actual temperature detection value. An actuator current control apparatus comprising: an interpolation calculation means for calculating by interpolation based on the plurality of correction values.   The current detection value correction means according to claim 1, wherein the current detection value correction means stores a plurality of correction values corresponding to each combination of a plurality of different temperature detection values and a plurality of different target current values, and an actual temperature detection value. An actuator current control device comprising means for reading the stored correction value and correcting the detected current value in accordance with a combination of the actual target current value.   4. The interpolation according to claim 3, wherein the current detection value correction means calculates an actual temperature detection value and a correction value corresponding to the actual target current value by interpolation based on the plurality of correction values stored in the storage means. An actuator current control device comprising a calculation means.   5. The current control device according to claim 1, wherein the current control device is an automatic transmission control device installed in the vicinity of or inside the vehicle automatic transmission, and the oil temperature of the hydraulic oil of the vehicle automatic transmission is The temperature detection is performed by estimating the temperature in or near the vehicle automatic transmission based on the oil temperature of the hydraulic oil of the vehicle automatic transmission detected by the oil temperature sensor. An actuator current control device comprising temperature estimation means for obtaining a value.   In the current control method of the actuator that performs feedback control so that the current flowing through the actuator is detected by the current detection means and the current detection value approaches the target current, the temperature in the vicinity of the current detection means is detected, and the temperature detection value The current detection value is corrected in accordance with the actuator current control method.   7. A plurality of correction values respectively corresponding to a plurality of different temperature detection values are stored, and correction values corresponding to other different actual temperature detection values are calculated by interpolation based on the plurality of stored correction values. A method for controlling the current of an actuator.   In claim 6, a plurality of correction values are stored for each combination of a plurality of different temperature detection values and a plurality of different target current values, and according to a combination of the actual temperature detection value and the actual target current value. An actuator current control method comprising: reading out the plurality of correction values to correct the detected current value.   9. The actuator current control method according to claim 8, wherein a correction value corresponding to the actual temperature detection value and the actual target current value is calculated by interpolation based on the plurality of stored correction values.   The oil temperature of the hydraulic oil of the vehicle automatic transmission is detected by an oil temperature sensor according to any one of claims 6 to 9, and based on the detected oil temperature, the automatic transmission in the vicinity of or inside the vehicle automatic transmission is detected. An actuator current control method characterized in that a temperature of a transmission control device is estimated and used as the temperature detection value.

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