JP2019120349A - Control device of continuously variable transmission - Google Patents

Abstract

[Problem] To provide a control device for a continuously variable transmission that can suppress deterioration of gear shift tracking when feedback control is resumed after a feedback integral term is reset. [Solution] In a control device for a continuously variable transmission that does not have a primary hydraulic pressure detection sensor that detects the primary hydraulic pressure of a primary pulley, but has a secondary hydraulic pressure detection sensor that detects the secondary hydraulic pressure of a secondary pulley, and that performs feedforward control and feedback control of an actual gear ratio with respect to a target gear ratio, when the influence of thrust ratio error and estimated torque error on the feedback integral term is sufficiently small compared to the influence of primary pressure error on the feedback integral term, and the actual gear ratio has converged to the target gear ratio, the value of the feedback integral term is learned as a primary hydraulic pressure error value. [Selected Figure] Figure 5

Description

  The present invention relates to a control device for a continuously variable transmission.

  Patent Document 1 discloses feedback (FB) control of an actual gear ratio with respect to a target gear ratio in a control device for a continuously variable transmission provided with a secondary hydraulic pressure sensor only in a secondary pulley.

Patent No. 5403164

  However, when performing feed forward (FF) control and feedback control, the feedback integral term includes primary hydraulic error and feed forward control error (thrust ratio map error and estimated torque error), but the feed forward control error is Since it is an error of the ratio of the thrust of the secondary pulley and the thrust of the primary pulley, the feedback integral term is fluctuated with the change of the secondary hydraulic pressure. In addition, when feedback control can not be used, it is possible to reset the feedback integral term so as not to receive unnecessary influence, but when feedback control is restarted, the shift followability deteriorates until the feedback integral term converges. It will

  The present invention has been made in view of the above problems, and an object thereof is a continuously variable transmission capable of suppressing deterioration in shift followability at the time of resuming feedback control after resetting a feedback integral term. Providing a control device for

  In order to solve the problems described above and achieve the object, the controller for a continuously variable transmission according to the present invention does not include a primary hydraulic pressure detection sensor that detects primary hydraulic pressure of a primary pulley, and detects secondary hydraulic pressure of a secondary pulley. Control device for a continuously variable transmission that performs feedforward control and feedback control of an actual gear ratio with respect to a target gear ratio, in which a thrust ratio error and an estimated torque error affect the feedback integral term. Learning the value of the feedback integral term as a primary hydraulic pressure error value when the primary pressure error is sufficiently small compared to the influence exerted on the feedback integral term and the actual gear ratio converges to the target gear ratio. It is characterized by

  The controller of the continuously variable transmission according to the present invention learns the value of the feedback integral term as the primary hydraulic pressure error value in the case where the primary hydraulic pressure learning accuracy can be ensured, so the feedback integral term is changed even if the secondary hydraulic pressure changes. The primary hydraulic pressure error, which is an error that does not fluctuate, can be learned, and it is possible to suppress the deterioration in shift followability at the time of resuming feedback control after resetting the feedback integral term.

FIG. 1 is a view for explaining a schematic configuration of a power transmission path from an engine constituting a vehicle according to the embodiment to driving wheels. FIG. 2 is a diagram showing a portion for driving the continuously variable transmission in the hydraulic control circuit. FIG. 3 is a block diagram for explaining an essential part of a control system provided in a vehicle for controlling an engine, a continuously variable transmission, and the like. FIG. 4 is a block diagram showing an example of a primary pressure hydraulic control structure. FIG. 5 is a flowchart showing an example of learning control of the integral term of the primary feedback thrust performed by the electronic control device in block B5 of FIG.

  An embodiment of a control device for a continuously variable transmission according to the present invention will be described below. The present invention is not limited by the present embodiment.

  FIG. 1 is a view for explaining a schematic configuration of a power transmission path from an engine 12 to a drive wheel 24 constituting a vehicle 10 according to the embodiment. In FIG. 1, for example, the power generated by the engine 12 used as a driving power source for traveling is a torque converter 14, a forward / reverse switching device 16, a belt type continuously variable transmission 18, a reduction gear device 20, a differential It transmits to the drive wheel 24 on either side via gear apparatus 22 grade | etc., Sequentially.

  The torque converter 14 is a pump impeller 14p connected to the crankshaft 13 of the engine 12 and a turbine wheel connected to the forward / reverse switching device 16 via a turbine shaft 30 corresponding to an output side member of the torque converter 14 It is equipped with 14t and is designed to perform power transmission via fluid. Further, a lockup clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t, and the pump impeller 14p and the turbine impeller 14t are integrated by fully engaging the lockup clutch 26. It is rotated. In the pump impeller 14p, the transmission control of the continuously variable transmission 18 is performed, the belt clamping force in the continuously variable transmission 18 is generated, the torque capacity of the lockup clutch 26 is controlled, A mechanical oil pump 28 is connected to generate hydraulic pressure for switching the power transmission path and supplying lubricating oil to each part of the power transmission path of the vehicle 10 by being rotationally driven by the engine 12 There is.

  The forward / reverse switching device 16 mainly includes a forward clutch C1, a reverse brake B1, and a double pinion type planetary gear set 16p. The turbine shaft 30 of the torque converter 14 is integrally coupled to the sun gear 16s of the planetary gear set 16p. Further, the input shaft 32 of the continuously variable transmission 18 is integrally connected to the carrier 16c of the planetary gear set 16p. On the other hand, the carrier 16c and the sun gear 16s are selectively connected via the forward clutch C1, and the ring gear 16r of the planetary gear device 16p is selectively connected to the housing 34 as a non-rotational member via the reverse brake B1. It is supposed to be fixed. The forward clutch C <b> 1 and the reverse brake B <b> 1 correspond to an interrupting device, and are both hydraulic friction engagement devices frictionally engaged by a hydraulic cylinder.

  In the forward / reverse switching device 16 configured as described above, when the forward clutch C1 is engaged and the reverse brake B1 is released, the forward / reverse switching device 16 is brought into an integral rotation state, whereby the turbine shaft 30 is rotated. Is directly connected to the input shaft 32, and a forward power transmission path is established, whereby the driving force in the forward direction is transmitted to the continuously variable transmission 18 side. Further, when the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 16 establishes a reverse power transmission path, and the input shaft 32 is reverse to the turbine shaft 30. It is made to rotate in the direction, and the driving force in the reverse direction is transmitted to the continuously variable transmission 18 side. When the forward clutch C1 and the reverse brake B1 are both released, the forward / reverse switching device 16 is brought into the neutral state (power transmission interruption state) in which the power transmission is interrupted.

  The engine 12 is configured by an internal combustion engine such as, for example, a gasoline engine or a diesel engine. The intake pipe 36 of the engine 12 is provided with an electronic throttle valve 40 for electrically controlling the amount of intake air of the engine 12 using a throttle actuator 38.

  The continuously variable transmission 18 is an input-side member provided on the input shaft 32. The primary pulley 42 is an input-side variable pulley having a variable effective diameter, and an effective diameter is an output-side member provided on the output shaft 44. Is a variable output side variable pulley, and a transmission belt 48 wound around the primary pulley 42 and the secondary pulley 46. The primary pulley 42, the secondary pulley 46, and the transmission belt 48 Power transmission is performed via the frictional force between them.

  Primary pulley 42 has a fixed sheave 42a fixed to input shaft 32, a movable sheave 42b provided so as to be relatively non-rotatable and axially movable about an axis with respect to input shaft 32, and a V groove between them A primary-side hydraulic cylinder 42c is provided to apply a primary thrust Win (= primary pressure Pin × pressure receiving area), which is an input-side thrust in the primary pulley 42 for changing the width. Further, the secondary pulley 46 has a fixed sheave 46a fixed to the output shaft 44, a movable sheave 46b provided so as not to be relatively rotatable around the axis with respect to the output shaft 44 and axially movable. A secondary side hydraulic cylinder 46c is provided to apply a secondary thrust Wout (= secondary pressure Pout × pressure receiving area) which is an output side thrust of the secondary pulley 46 for changing the V groove width.

The primary pressure Pin, which is the hydraulic pressure to the primary hydraulic cylinder 42c, and the secondary pressure Pout, which is the hydraulic pressure to the secondary hydraulic cylinder 46c, are independently controlled by the hydraulic control circuit 21 (see FIG. 3). , And the primary thrust Win and the secondary thrust Wout are controlled. Thereby, the V groove width of primary pulley 42 and secondary pulley 46 is changed to change the hooking diameter (effective diameter) of transmission belt 48, and gear ratio γ (= input shaft rotational speed Nin / output shaft rotational speed Nout) is The friction force (belt clamping force) between the primary pulley 42 and the secondary pulley 46 and the transmission belt 48 is controlled so that the transmission belt 48 is continuously changed and the transmission belt 48 does not slip. As described above, by controlling the primary thrust Win and the secondary thrust Wout, the actual transmission ratio γact, which is the actual transmission ratio γ, is made the target transmission ratio γ ^* while the slip of the transmission belt 48 is prevented. The input shaft rotational speed Nin is the rotational speed of the input shaft 32, and the output shaft rotational speed Nout is the rotational speed of the output shaft 44. Further, as can be seen from FIG. 1, the input shaft rotational speed Nin is the same as the rotational speed of the primary pulley 42, and the output shaft rotational speed Nout is the same as the rotational speed of the secondary pulley 46.

  In the continuously variable transmission 18, for example, when the primary pressure Pin is increased, the V groove width of the primary pulley 42 is narrowed and the speed ratio γ is decreased, that is, the continuously variable transmission 18 is upshifted. Further, when the primary pressure Pin is lowered, the V groove width of the primary pulley 42 is increased to increase the gear ratio γ, that is, the continuously variable transmission 18 is downshifted. Therefore, when the V groove width of the primary pulley 42 is minimized, the minimum gear ratio γmin (highest speed gear ratio, highest Hi) is formed as the gear ratio γ of the continuously variable transmission 18. Further, when the V groove width of the primary pulley 42 is maximized, the maximum transmission ratio γmax (the lowest speed transmission ratio, the lowest) is formed as the transmission ratio γ of the continuously variable transmission 18.

  FIG. 2 is a view showing a portion of the hydraulic control circuit 21 which drives the continuously variable transmission 18. In the hydraulic control circuit 21, the oil discharged from the oil pump 28 is supplied to the oil passage 71. The oil passage 71 supplies oil to the primary pulley 42 of the continuously variable transmission 18 to apply hydraulic pressure to the primary pulley 42 and also supplies oil to the secondary pulley 46 of the continuously variable transmission 18 to the secondary pulley 46. It is for acting hydraulic pressure.

  The hydraulic control circuit 21 is provided with a primary regulator valve 72 that regulates the oil discharge pressure of the oil pump 28 to a line pressure that is a hydraulic pressure used for hydraulic drive of the continuously variable transmission 18 or the like. Further, the hydraulic control circuit 21 includes a primary pulley control valve 75 that regulates the hydraulic pressure acting on the primary pulley 42 based on the line pressure, and a secondary that similarly regulates the hydraulic pressure acting on the secondary pulley 46 based on the line pressure. A pulley control valve 73 is provided. The primary pulley control valve 75 is driven and controlled by the linear solenoid valve 76 using hydraulic pressure, and the secondary pulley control valve 73 is driven and controlled by the linear solenoid valve 74 using hydraulic pressure.

With regard to adjustment of the hydraulic pressure acting on the secondary pulley 46, the secondary thrust Wout generated in the axial direction of the secondary pulley 46 (FIG. 1) based on the action of the hydraulic pressure through drive control of the linear solenoid valve 74 42 and the secondary pulley 46 so as not to cause a slip. Further, regarding adjustment of the hydraulic pressure acting on primary pulley 42, primary thrust Win generated in the axial direction of primary pulley 42 (FIG. 1) based on the action of the hydraulic pressure through drive control of linear solenoid valve 76 is target gear ratio γ ^* To be a feasible value. For example, when changing the gear ratio γ to the low side, the hydraulic pressure acting on the primary pulley 42 is made small so that the primary thrust Win becomes small, and when changing the gear ratio γ to the hi side The hydraulic pressure acting on the primary pulley 42 is made large so that the primary thrust Win becomes large.

  FIG. 3 is a block diagram for explaining the main parts of a control system provided in the vehicle 10 to control the engine 12, the continuously variable transmission 18, and the like. In FIG. 3, the vehicle 10 is provided with an electronic control unit 110 having a function as a control device for a transmission related to, for example, transmission control of the continuously variable transmission 18. The electronic control unit 110 is configured to include, for example, a so-called microcomputer provided with a CPU, a RAM, a ROM, an input / output interface and the like, and the CPU follows a program stored in advance in the ROM using a temporary storage function of the RAM. By performing signal processing, various controls of the vehicle 10 are executed. For example, the electronic control unit 110 is configured to execute output control of the engine 12, shift control of the continuously variable transmission 18, belt clamping pressure control, and the like.

The electronic control unit 110, the rotation angle _{(position) A CR} and a signal representative of the rotational speed (engine rotational speed) _{N E} of the engine 12 of the crankshaft 13 detected by the engine rotational speed sensor 120, a turbine speed sensor 121 A signal representing the detected rotational speed (turbine rotational speed) _NT of the input shaft 32 (turbine shaft), the input rotational speed N of the continuously variable transmission 18 detected by the input shaft rotational speed sensor 122 A signal representing _in , a signal representing an output shaft rotational speed N _out which is an output rotational speed of the continuously variable transmission 18 corresponding to the vehicle speed V detected by the output shaft rotational speed sensor 123, an electronic throttle detected by the throttle sensor 124 signal representing the throttle valve opening theta _TH of the valve, the detected driver's acceleration request by the accelerator opening sensor 125 Signal representing the accelerator opening A _CC is an operation amount of the accelerator pedal as a signal representing the brake on B _ON that indicates the state in which the foot brake is operated is a service brake, which is detected by a foot brake switch 126, a lever position sensor lever position of a shift lever which is detected by the 127 signal representing the (operating position) P _SH, such as a signal representative of the secondary pressure Pout is a hydraulic pressure supplied to the secondary pulley 46 detected by the secondary pressure sensor 128 is supplied . The electronic control unit 110 sequentially calculates the actual gear ratio γact (= N _in / N _out ) of the continuously variable transmission 18 based on, for example, the output shaft rotational speed N _out and the input shaft rotational speed N _in .

Further, the electronic control unit 110, and an engine output control command signal S _E for the output control of the engine 12, a hydraulic control command signal S _CVT for hydraulic control over the shift of the continuously variable transmission 18, respectively output Be done. Specifically, as the engine output control command signal S _E, to control the amount of fuel injected from the throttle signal and the fuel injection device 131 for controlling the opening and closing of the electronic throttle valve to the throttle actuator 130 And an ignition timing signal for controlling the ignition timing of the engine 12 by the ignition device 132, and the like. As the oil pressure control command signal S _CVT, and a command signal for driving a linear solenoid valve 76 which applies the primary pressure Pin tone, such a command signal for driving a linear solenoid valve 74 for pressurizing the secondary pressure Pout tone, It is output to the hydraulic control circuit 21.

FIG. 4 is a block diagram showing an example of the hydraulic control structure of the primary pressure Pin. In FIG. 4, the input torque Tin to the primary pulley 42 and the target gear ratio γ ^* are sequentially calculated by the electronic control unit 110.

The electronic control device 110 is expressed by the following equation (1), for example, from the thrust ratio τ obtained from a thrust ratio map set in advance based on the input torque Tin input to the primary pulley 42 and the target gear ratio γ ^*. The primary sheave balance thrust Winbl is calculated using the primary sheave balance thrust formula (block B1 in FIG. 4).

  Then, the electronic control unit 110 adds the primary shift differential thrust, which is a differential thrust on primary pulley side conversion when realizing the target shift on the primary pulley 42 side, to the calculated primary sheave balance thrust Winbl. The primary feed forward thrust Winff is calculated (block B2 in FIG. 4).

Further, the electronic control device 110 uses, for example, a feedback control equation as shown in the following equation (2) based on the gear ratio deviation (= γ ^* −γ) Δγ of the target gear ratio γ ^* and the actual gear ratio γact. Then, the primary feedback thrust Winfb for making the actual gear ratio γact coincide with the target gear ratio γ ^* is calculated (block B3 and block B4 in FIG. 4). In the following equation (2), KP in the proportional term (FB thrust proportional term) is a proportional gain (predetermined proportional constant), and KI in the integral term (FB thrust integral term) is an integral gain (predetermined integral constant) It is.

  Then, the electronic control unit 110 sets a value corrected by the primary feedback thrust Winfb as a target primary thrust with respect to the primary feed forward thrust Winff.

  Further, the electronic control unit 110 learns the value of the integral term at the time of calculating the primary feedback thrust Winfb using the equation (2) as a Pin error value when a predetermined condition is satisfied (FIG. 4). Block B5).

Then, the electronic control unit 110 converts the target primary thrust into a target primary pressure based on the pressure receiving area of the primary side hydraulic cylinder 42c, and corrects the converted target primary pressure by the learned integral term to obtain a primary command pressure. Set Pintgt (eg, block B6 in FIG. 4). The electronic control unit 110 outputs a primary instruction pressure Pintgt to the hydraulic control circuit 21 as the hydraulic pressure control command signal _{S CVT.} The hydraulic control circuit 21 operates the linear solenoid valve 76 to adjust the primary pressure Pin in accordance with the hydraulic control command signal S _CVT .

  FIG. 5 is a flowchart showing an example of learning control of the integral term of the primary feedback thrust Winfb performed by the electronic control unit 110 in block B5 of FIG.

  First, the electronic control device 110 calculates a learnable region by estimating the amount of error between the first term and the second term on the right side based on the error propagation equation by the moment method shown in the following equation (3): It is determined whether the effect of the thrust ratio error and the estimated torque error on the integral term is sufficiently small (a region in which the Pin learning accuracy can be ensured) as compared to the influence of the Pin error on the integral term (step S1). In the following equation (3), T is the estimated belt input torque, R is the belt diameter, μ is the friction coefficient between the belt and the pulley, α is the sheave angle, Ain is the pressure receiving area of the primary hydraulic cylinder 42c, σWin is The primary sheave thrust error (= integral term), στ is a thrust ratio error, σT is an estimated torque error, and σPin is a variation of the primary pressure Pin.

If it is determined in step S1 that the area is not sufficiently small (the area is not enough to ensure Pin learning accuracy) (No in step S1), the electronic control unit 110 performs a series of control without learning the integral term. finish. On the other hand, when it is determined in step S1 that the value is sufficiently small (the area where the Pin learning accuracy can be secured) (Yes in step S1), the electronic control unit 110 determines that the target gear ratio γ ^* is constant (the target gear speed is It is determined whether it is 0) (step S2). If it is determined that the target gear ratio γ ^* is not constant (No in step S2), the electronic control unit 110 ends the series of control without learning the integral term. On the other hand, when it is determined that the target gear ratio γ ^* is constant (Yes in step S2), the electronic control unit 110 determines that the actual gear ratio γact converges to the target gear ratio γ ^* (the above integral term converges (Step S3). If it is determined that the actual gear ratio γact does not converge to the target gear ratio γ ^* (No in step S3), the electronic control unit 110 ends the series of control without learning the integral term. On the other hand, when it is determined that the actual gear ratio γact converges to the target gear ratio γ ^* (Yes in step S3), the electronic control unit 110 carries out learning with the integral term as the Pin error equivalent (Pin error value). (Step S4). Then, the electronic control unit 110 ends the series of control.

  When the influence of the thrust ratio error and the estimated torque error on the integral term is sufficiently smaller than the influence of the Pin error on the integral term (a region in which the Pin learning accuracy can be ensured), the integral term is primary Only the deviation amount of the actual primary pressure Pinact from the command pressure Pintgt is accumulated. Therefore, the electronic control device 110 learns the value of the integral term as the Pin error value in the area where the Pin learning accuracy can be ensured, and therefore the error does not change the integral term even if the secondary pressure Pout changes. The Pin error, which is Therefore, when feedback control is restarted after the integral term is reset, it is possible to suppress deterioration in shift followability immediately after the start of feedback control.

18 continuously variable transmission 42 primary pulley 46 secondary pulley 110 electronic control unit 128 secondary pressure sensor

Claims (1)

It does not have a primary oil pressure detection sensor for detecting the primary oil pressure of the primary pulley, but has a secondary oil pressure detection sensor for detecting the secondary oil pressure of the secondary pulley, and performs feedforward control and feedback control of the actual gear ratio to the target gear ratio. In the transmission control device,
The effect of the thrust ratio error and the estimated torque error on the feedback integral term is sufficiently small compared to the effect of the primary pressure error on the feedback integral term,
When the actual gear ratio converges to the target gear ratio,
A controller for a continuously variable transmission, comprising: learning a value of the feedback integral term as a primary hydraulic pressure error value.

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