JP4068000B2 - Electromagnetic actuator control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electromagnetic actuator used in a torque transmission mechanism of an electronically controlled four-wheel drive vehicle or the like.
[0002]
[Prior art]
For example, a torque transmission mechanism of an electronically controlled four-wheel drive vehicle includes a pair of left and right planetary gear sets and a pair of brake mechanisms (clutch mechanisms) for variably controlling the torque of a sun gear coupled to each planetary gear set. . Each brake mechanism (clutch mechanism) includes a wet multi-plate brake (clutch) and an electromagnetic actuator that operates the multi-plate brake (clutch).
[0003]
The electromagnetic actuator includes a core (yoke) having an annular groove, a solenoid inserted in the annular groove of the core, an armature arranged to face the core with a predetermined gap, and a piston connected to the armature It consists of.
[0004]
When a current is applied to the solenoid, the armature is attracted to the core by the solenoid to generate thrust. Due to this thrust, the piston connected integrally with the armature presses the multi-plate brake (clutch), thereby generating brake torque (clutch torque).
[0005]
The output torque to the left and right rear axles can be variably controlled by controlling the current value flowing through the left and right solenoids based on the turning direction and the steering force or steering angle.
[0006]
As a conventional solenoid drive current control method, a combination of current feedback control using a PID controller and current control using a pulse width modulation (PWM) duty signal using a switching element and a current return diode is generally used. Has been done.
[0007]
By adjusting the proportional term constant, integral term constant, and derivative term constant of the PID controller to optimum values, the steady deviation of the drive current (actual current) with respect to the target current is eliminated, so that an appropriate overshoot occurs at the time of current rise. Operate.
[0008]
[Patent Document 1]
JP 2002-39231 A
[Patent Document 2]
Japanese Patent Laid-Open No. 2002-225581
[Patent Literature]
Japanese Patent Laid-Open No. 2002-227882
[Problems to be solved by the invention]
However, current feedback control using a conventional PID controller has a problem that an actual current with respect to a target current at the time of current rising is delayed, drive torque response is deteriorated, and a problem occurs in vehicle behavior.
[0012]
In addition, the brake (clutch) plate and the brake (clutch) disc of the wet multi-plate brake (clutch) deteriorate due to aging (wear), and the initial gap between the core and the armature when the solenoid is de-energized decreases accordingly. . When the initial gap decreases, there is a problem that the inductance component of the solenoid increases and the responsiveness at the start of current deteriorates.
[0013]
Therefore, an object of the present invention is to provide a control device for an electromagnetic actuator capable of improving a current rising characteristic in PWM duty drive of a solenoid.
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a core member having a groove, a solenoid housed in the groove of the core member, and an armature member arranged to face the core member with a gap. An electromagnetic actuator control device comprising: means for detecting a gap between the core member and the armature member; current detecting means for detecting an actual current flowing through the solenoid; and an actual current matching a target current. A feedback controller for feedback control, a feedforward controller for feedforward control of a target current, and a solenoid drive signal generation means for generating a solenoid drive signal based on outputs of the feedback controller and the feedforward controller. comprising the feedback controller when the gap is large Select deal of integral term constant, the control unit of the electromagnetic actuator, characterized by selecting a smaller integral term constant as the gap is reduced is provided.
[0015]
According to this configuration, since the smaller integral term constant is selected as the gap becomes smaller , the rising response of the actual current can be improved and the convergence to the steady state can be quickly achieved by feedback control.
[0022]
According to the second aspect of the present invention, the feedforward controller selects a small transfer function and / or a small gain when the gap is large, and controls an electromagnetic actuator that selects a larger transfer function and / or gain as the gap is small. An apparatus is provided.
[0023]
The inductance component of the solenoid is small when the gap is large and increases as the gap is small. Therefore, since the rising response of the actual current becomes worse as the gap becomes smaller, a larger transfer function and / or larger gain is selected as the gap becomes smaller, and the target current is controlled by feedforward control, so that Therefore, an appropriate overshoot can be generated at the rise of the actual current, and the rise response of the actual current can be improved.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, there is shown a schematic diagram of a power transmission device for a four-wheel drive vehicle based on a front engine / front drive (FF) vehicle to which the solenoid drive device of the present invention can be applied.
[0025]
As shown in FIG. 1, the power transmission system includes a front differential device 6 in which power from an engine 2 disposed in front of the vehicle is transmitted from an output shaft 4a of a transmission 4, and power from the front differential device 6 is propeller shaft. 8 mainly includes a speed increasing device (transmission device) 10 that is transmitted through a rear differential device 12 to which power from the speed increasing device 10 is transmitted.
[0026]
The front differential device 6 has a conventionally known structure, and the power from the output shaft 4a of the transmission 4 is transmitted to the left and right front wheel drive shafts 20 and 22 via the plurality of gears 14 and the output shafts 16 and 18 in the differential case 6a. By transmitting, each front wheel is driven.
[0027]
As will be described later, the rear differential device 12 includes a pair of planetary gear sets and a pair of electromagnetic actuators for controlling the engagement of a multi-plate brake mechanism (multi-plate clutch mechanism), and controls the electromagnetic actuator. Each rear wheel is driven by transmitting power to the left and right rear wheel drive shafts 24, 26.
[0028]
FIG. 2 is a cross-sectional view of the speed increasing device (transmission device) 10 and the rear differential device 12 disposed on the downstream side of the speed increasing device 10. The speed increasing device 10 includes an input shaft 30 rotatably mounted in a casing 28 and an output shaft (hypoid pinion shaft) 32.
[0029]
The speed increasing device 10 further includes an oil pump subassembly 34, a planetary carrier subassembly 38, a direct coupling clutch subassembly 40, and a speed change brake 42.
[0030]
The rear differential device 12 provided on the downstream side of the speed increasing device 10 has a hypoid pinion gear 44 formed at the tip of the hypoid pinion shaft 32.
[0031]
The hypoid pinion gear 44 meshes with the hypoid ring gear 48, and the power from the hypoid ring gear 48 is input to the ring gears of the planetary gear sets 50A and 50B provided on the left and right.
[0032]
The sun gears of the planetary gear sets 50A and 50B are rotatably mounted around the left rear axle 24 and the right rear axle 26. The planetary carriers of the planetary gear sets 50A and 50B are fixed to the left rear axle 24 and the right rear axle 26. A planet gear carried on the planetary carrier meshes with the sun gear and the ring gear.
[0033]
The left and right planetary gear sets 50A and 50B are connected to a brake mechanism 51 (clutch mechanism) provided for variably controlling the torque of the sun gear. The brake mechanism (clutch mechanism) 51 includes a wet multi-plate brake (clutch) 52 and an electromagnetic actuator 56 that operates the multi-plate brake (clutch) 52.
[0034]
The brake (clutch) plate of the wet multi-plate brake (clutch) 52 is fixed to the casing 54, and the brake (clutch) disk is fixed to the sun gears of the planetary gear sets 50A and 50B.
[0035]
The electromagnetic actuator 56 includes a ring-shaped core (yoke) 58 having an annular groove, an annular solenoid 60 inserted into the annular groove of the ring-shaped core 58, and a ring-shaped facing the ring-shaped core 58 with a predetermined gap. An armature 62 and an annular piston 64 connected to the armature 62 are included.
[0036]
When a current is applied to the solenoid 60, the armature 62 is attracted to the core 58 by the solenoid 60 and a thrust is generated. Due to this thrust, the piston 64 integrally connected to the armature 62 presses the multi-plate brake (clutch) 52, thereby generating a brake (clutch) torque.
[0037]
As a result, the sun gears of the planetary gear sets 50A and 50B are fixed to the casing 54, respectively, and the driving force of the hypoid pinion shaft 32 passes through the ring gear, planet gear, and planet carrier of the planetary gear sets 50A and 50B. 26.
[0038]
By controlling the current flowing through the annular solenoid 60, the driving force of the input shaft 30 can be distributed directly to the left and right rear axles 24, 26 in a directly connected state or with the speed increasing device 10 and is optimal. Turning control can be realized.
[0039]
A search coil 66 is attached adjacent to each solenoid 60. The magnetic flux intensity when the solenoid 60 is energized by the search coil 66 is detected, the gap is estimated based on the detected magnetic flux intensity, and feedback and feedforward control corresponding to the magnetic flux are performed on the solenoid 60.
[0040]
Referring to FIG. 3, there is shown a principle diagram of the electromagnetic actuator control apparatus of the present invention. The electromagnetic actuator has a core member having a groove, a solenoid 60 accommodated in the groove of the core member, and an armature member arranged to face the core member with a gap.
[0041]
The control device for the electromagnetic actuator is composed of a feedforward type two-degree-of-freedom control system, and includes an initial gap detecting means 70 for detecting an initial gap between the core member and the armature member when the solenoid 60 starts to operate. . The initial gap detecting means 70 detects the gap when the solenoid operation is stopped or when the operation is started, or takes the average of these to obtain the initial gap.
[0042]
The actual current flowing through the solenoid 60 is detected by the current detection means 72. The target current (command current) is input to the subtractor 76 via the target filter 74.
[0043]
The target filter 74 is a primary filter obtained by dividing the actual current by the target current, and the response of the entire control device is determined by the characteristics of the target filter.
[0044]
The subtractor 76 subtracts the actual current detected by the current detector 72 from the target current that has passed through the target filter 74, and the difference is input to a PID controller (feedback controller) 78. The PID controller 78 performs feedback control so that the actual current matches the target current.
[0045]
The PID controller 78 changes the integral term constant according to the initial gap detected by the initial gap detector 70. For example, one of a plurality of integral term constants set in advance is selected according to the initial gap.
[0046]
The feedforward controller 80 performs feedforward control of the target current. That is, the feedforward controller 80 feedforward-controls the target current by changing the transfer function and gain according to the initial gap detected by the initial gap detecting means 70.
[0047]
For example, the feedforward controller 80 selects one of a plurality of preset transfer functions and a plurality of gains according to the initial gap.
[0048]
The output of the PID controller 78 and the output of the feedforward controller 80 are added by an adder 82, and the sum is input to a pulse width modulation (PWM) duty signal generation means (solenoid drive signal generation means) 84.
[0049]
The PWM duty signal generation means 84 generates a PWM duty signal (solenoid drive signal) based on the sum of the outputs of the PID controller 78 and the feedforward controller 80, and drives the solenoid 60 based on the PWM duty signal.
[0050]
When an actual current is passed through the solenoid 60, the armature 62 of the electromagnetic actuator 56 shown in FIG. 2 is attracted to the core 58 by the solenoid 60 to generate thrust. Due to this thrust, the piston 64 integrally connected to the armature 62 presses the multi-plate brake (clutch) 52, thereby generating a brake (clutch) torque.
[0051]
The configuration of the PID controller 78 according to the embodiment of the present invention will be described with reference to FIG. The PID controller 78 has a proportional term constant 86, five integral term constants 88 # 1 to 88 # 5, and a derivative term constant 100.
[0052]
The value of the proportional term constant 86 is 2, for example. The values of the integral term constants 88 # 1 and 88 # 2 are 0.6, the value of the integral term constant 88 # 3 is 0.5, and the values of the integral term constants 88 # 4 and 88 # 5 are 0.33. It is.
[0053]
The integral term constant 88 # 1 is applied when the initial gap is large, and the integral term constants 88 # 2 to 88 # 5 are applied as the initial gap becomes smaller. Of course, the values of the five integral term constants 88 # 1 to 88 # 5 may be set to different values.
[0054]
The PID controller 78 further has a derivative term constant 100. In this embodiment, since the value of the differential term constant 100 is 0, the differential term control is not actually performed.
[0055]
The magnetic flux intensity detected by the search coil 66 is converted into an initial gap by a map 90 in which the magnetic flux intensity and the initial gap are associated with each other, and any one of the integral term constants 88 # by the multipoint switch 92 corresponding to the initial gap. 1-88 # 5 is selected.
[0056]
The target current is input to the subtractor 76 via the target filter 74, the actual current is subtracted from the target current by the subtractor 76, and the difference is input to the PID controller 78.
[0057]
In the calculation of the proportional term of the PID controller 78, the output of the subtracter 76 is multiplied by the proportional term constant 2 and the product is input to the adder 106. In the calculation of the integral term, the output of the subtractor 76 is multiplied by an integral term constant selected according to the initial gap, for example, 0.6, and the product is input to the adder 94.
[0058]
In the adder 94, the current value output from the multipoint switch 92 and the previous value 98 are added, and the sum is input to the adder 106 via the limiter 96.
[0059]
In the calculation of the differential term, the output of the subtractor 76 is multiplied by a differential term constant 0, the previous value 104 is subtracted from the product by the subtractor 102, and the difference is input to the adder 106. As described above, in this embodiment, since the value of the differential term constant 100 is 0, the differential term calculation is not performed.
[0060]
The adder 106 adds the value of the proportional term, the value of the integral term, and the value of the derivative term, and outputs the sum via the limiter 108.
[0061]
In the PID controller 78 of the present embodiment, a large integral term constant is set when the initial gap is large, and the integral term constant is set to decrease stepwise as the initial gap becomes small. Such a set value is based on a learned value learned in advance by experiments.
[0062]
As described above, since the optimum integral term constant is selected according to the detected initial gap, it is possible to improve the rise response of the actual current during PWM driving and to quickly achieve convergence to the target current. it can.
[0063]
FIG. 5 shows a configuration of the feedforward controller 80 according to the embodiment of the present invention. The feedforward controller 80 has five transfer functions 110 # 1 to 110 # 5 and five gains 116 # 1 to 116 # 5.
[0064]
The transfer functions 110 # 1 to 110 # 5 are arranged in ascending order of values. When the initial gap is large, the smallest transfer function 110 # 1 is selected, and as the initial gap decreases, the transfer functions 110 # 2 to 110 # 5 are selected. Is selected.
[0065]
Similarly, the gains 116 # 1 to 116 # 5 are arranged in ascending order of values, and the smallest gain 116 # 1 is applied when the initial gap is large, and gains 116 # 2 to 116 # 5 as the initial gap becomes smaller. Applies.
[0066]
The magnetic flux intensity detected by the search coil 66 is converted into an initial gap by a magnetic flux intensity-initial gap conversion map 112. Based on this initial gap, the multipoint switch 114 selects the optimal transfer function, eg, transfer function 110 # 2, and the multipoint switch 118 selects the gain 116 # 2 corresponding to the transfer function 110 # 2.
[0067]
The target current value is multiplied by the selected transfer function 110 # 2 and the product is supplied to the multiplier 120. Similarly, the target current value is multiplied by the selected gain 116 # 2, and the product is supplied to the multiplier 120. Multiplier 120 multiplies transfer function 110 # 2 and gain 116 # 2 and outputs the product via limiter 122.
[0068]
The output of the multiplier 120 and the output of the adder 106 shown in FIG. 4 are supplied to and added to the adder 82 of FIG. 3, and a PWM duty signal is generated by the PWM duty signal generation means 84 based on the sum.
[0069]
In the feedforward controller 80 of this embodiment, a small transfer function and a small gain are selected when the initial gap is large, and a larger transfer function and a gain are selected as the multi-plate brake 52 is worn and the initial gap becomes small. .
[0070]
The inductance component of the solenoid 60 is small when the initial gap is large, and the inductance component increases as the multi-plate brake 52 is worn and the initial gap becomes small.
[0071]
Therefore, since the rising response of the actual current becomes worse as the initial gap becomes smaller, in this embodiment, a larger transfer function and a larger gain are selected as the initial gap becomes smaller, and the target current is feedforward controlled.
[0072]
By controlling in this way, it is possible to improve the rising response of the actual current regardless of the size of the initial gap.
[0073]
In the embodiment described above, the PID controller 78 selects an optimum value corresponding to the initial gap from a plurality of integral term constants, and the feedforward controller 80 corresponds to the initial gap from a plurality of transfer functions and gains. The optimum transfer function and gain are selected.
[0074]
The electromagnetic actuator control apparatus of the present invention is not limited to the above-described embodiment. The transfer function and gain of the feedforward controller 80 are fixed to one set value, and the integral term constant of the PID controller 78 is fixed. May be changed according to the initial gap.
[0075]
Similarly, the integral term constant of the PID controller 78 may be fixed to one value, and the transfer function and gain of the feedforward controller 80 may be changed according to the initial gap.
[0076]
FIG. 6 shows current rising characteristics of the embodiment of the present invention when the indicated torque is 0 to 120 kgf · m and the conventional example of only feedback control. Curve A shows the current rise characteristic of the present invention when the initial gap is 1.4 mm, and curve B shows the current rise characteristic when the initial gap is 0.4 mm. On the other hand, the curve C shows the current rise characteristic of the conventional method when the initial gap is 1.4 mm, and the curve D shows the current rise characteristic when the initial gap is 0.4 mm.
[0077]
As is apparent from FIG. 6, the time until the current rises to 80% of the target current, that is, 0.8 A is about 50 msec for both the curves A and B, which is compared with the curves C and D of the current rise characteristic of the conventional method. It is clearly excellent in rising response.
[0078]
Furthermore, by giving a large feed-forward control amount as the initial gap becomes smaller and controlling so as to generate a large overshoot, it is possible to obtain the same real current rising response regardless of the initial gap. Can do. After the actual current is quickly raised, the target current can be quickly approached by feedback control.
[0079]
【The invention's effect】
According to the first aspect of the present invention, since the feedback controller changes the integral term constant according to the gap detected by the gap detecting means, it is possible to improve the rise characteristic of the actual current and to return to the steady state by feedback control. Convergence can be achieved quickly.
[0080]
According to the invention of claim 2, since the transfer function and / or gain of the feedforward controller is changed according to the gap, an appropriate overshoot can be generated at the rise of the actual current, and the actual current according to the gap. The rise characteristic can be improved. Therefore, in the invention of claim 2, in combination with the effect of the invention of claim 1, the rising response of the actual current can be improved more finely.
[0081]
According to the invention of claim 3, since the optimum integral term constant is selected according to the detected gap, the rise response of the actual current can be improved and the convergence to the target current can be achieved quickly. .
[0082]
According to the invention of claim 4, since the transfer function and / or gain of the feedforward controller is changed according to the gap, an appropriate overshoot can be generated at the rise of the actual current, and the actual current Rise response can be improved.
[0083]
The inductance component of the solenoid is small when the gap is large and increases as the gap is small. Therefore, since the rising response of the actual current becomes worse as the gap becomes smaller, in the invention of claim 5, a larger transfer function and / or larger gain is selected as the gap becomes smaller. Appropriate overshoot can be generated, and the rising response of the actual current can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a power transmission system of a four-wheel drive vehicle.
FIG. 2 is a cross-sectional view of a speed increasing device (transmission device) and a rear differential device.
FIG. 3 is a block diagram showing the principle configuration of the electromagnetic actuator control device of the present invention.
FIG. 4 is a diagram showing a configuration of a PID controller according to an embodiment of the present invention.
FIG. 5 is a diagram showing a configuration of a feedforward controller according to an embodiment of the present invention.
FIG. 6 is a diagram showing current rising characteristics of the present invention and a conventional example when the indicated torque is 0 to 120 kgf · m.
[Explanation of symbols]
10 Speed increaser (transmission)
12 Rear differential devices 24, 26 Rear axle 30 Input shaft 32 Output shaft (hypoid pinion shaft)
50A, 50B Planetary gear set 51 Brake mechanism 52 Wet multi-plate brake 56 Electromagnetic actuator 58 Core (yoke)
60 annular solenoid 62 armature 66 search coil 70 initial gap detecting means 72 current detecting means 74 target filter 78 PID controller 80 feedforward controller 84 PWM duty signal generating means

Claims (2)

A control device for an electromagnetic actuator, comprising: a core member having a groove; a solenoid housed in the groove of the core member; and an armature member disposed to face the core member with a gap therebetween.
Means for detecting a gap between the core member and the armature member;
Current detecting means for detecting an actual current flowing through the solenoid;
A feedback controller that performs feedback control so that the actual current matches the target current;
A feedforward controller for feedforward control of the target current;
Solenoid drive signal generating means for generating a solenoid drive signal based on the outputs of the feedback controller and the feedforward controller;
The feedback controller selects a large integral term constant when the gap is large, and selects a smaller integral term constant as the gap becomes small . Small transfer function and / or to select a smaller gain control device of an electromagnetic actuator according to claim 1, wherein selecting a larger transfer function and / or gain as the gap decreases when the feedforward controller has a large gap.

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