JPS63106144A - Constant speed drive unit for automobile - Google Patents

Abstract

PURPOSE:To make controlling undershoot and overshoot at time of setting of constant speed drive control restrainable, by operating an initial control value of the constant speed drive control on the basis of speed and acceleration of a vehicle. CONSTITUTION:An initial value operational device (e) operates an initial value control value of constant speed drive on the basis of speed and acceleration of a vehicle at time of the setting when constant speed drive control has been set. A controlling device (f) operates a control value controlling engine power so as to accord the existing car speed with the desired one when the constant speed drive control has been set, while at the time of setting the constant speed drive control, the control value is determined on the basis of the initial control value. An output adjusting device (g) operates the engine power on the basis of output of the controlling device (f).

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a constant speed running device for vehicles such as automobiles that uses a pneumatic actuator as an actuator for adjusting the opening degree of a throttle valve, and in particular, the present invention relates to a constant speed running device for vehicles such as automobiles, and in particular, initialization control in consideration of running resistance. This invention relates to a constant speed traveling device that determines output and aims for stable control. (Prior Art) Recently, A S CD (Auto 5peed Control) has been developed as a system that can automatically set the speed of a vehicle.
(rol dev-ice) has been developed and put into practical use, but in such a system, control stability is important, and this leads to a sense of security for the driver. An example of a conventional constant speed traveling device for automobiles of this type is the one described in Japanese Patent Application Laid-Open No. 61-30430. When set to drive at a constant speed, this device controls the air pressure in the pressure chamber of the actuator to reach the set vehicle speed according to the driving conditions, operates the diaphragm, and adjusts the opening of the throttle valve. There is. Therefore, the negative pressure and atmospheric pressure introduced into the pressure chamber are controlled, the throttle valve opening changes, and the engine output changes.
The vehicle speed is controlled to be equal to the set vehicle speed. In addition, by monitoring the acceleration of the vehicle and suppressing the amount of negative pressure introduced into the pressure chamber of the actuator when the acceleration is greater than a predetermined acceleration, the system is intended to prevent the actuator from rapidly increasing the vehicle speed. There is. (Problems to be Solved by the Invention) However, with such conventional constant speed driving devices for automobiles, there is a problem when the system starts operating and is set to constant speed driving, or when the function as a system operation switch is activated. The set initialize control output and accelerator set initialize output, which start operating when the accelerator is set, are configured to output individual fixed constants, for example, a predetermined constant or a correction value proportional to the vehicle speed. There is a problem in that the output becomes excessive on hills, resulting in large undershoots and overshoots, giving the driver a sense of insecurity in control. In order to drive the vehicle at a constant speed at the set speed, the engine output is output at a constant rate or in proportion to the vehicle speed within a certain period of time so that the engine torque (Te) = running resistance (R). It is from. To specifically describe the problem based on this situation, when there are running characteristics as shown in Fig. 7, the initialization constant output for running resistance at 0% slope is a linear approximation, assuming constant engine performance, gear ratio, etc. According to the idea of a function, it is given as a single pulse expressed by the following formula (■). Initialization constant output = K・V (tl...
・■ However, K: constant V(t): vehicle speed at the time of setting In the case of such a method, the following problems occur. (I) As shown in the figure, in the range of vt = 6 o ~ 80 km/h, the load resistance changes by about +2 times with a slope resistance of ±3%, and as a result, undershoot and overshoot become large, resulting in poor control. Gives the driver a sense of anxiety. (II) Similar to the above item (1), if the engine performance and gear ratio differ, the driving force will change significantly, and undershoot and overshoot will also occur. As a result of intensive investigation into the cause of the above-mentioned problem, the inventor found that the conventional system ignores gradient resistance, which is a major factor in running resistance, resulting in insufficient output on uphill slopes and excessive output on downhill slopes. I understood the fact that it happens. This means that, since each vehicle has different engine characteristics, gear ratios, and inertial resistance, it is necessary to appropriately change the constant value of the initial set output for each vehicle type, for example. That is, it is thought that this type of control output should originally take in a function on the load side where the forces are balanced, and feed back this. To explain using a mathematical formula, running resistance (R) is expressed by the following formula (2). Running resistance (R) - rolling resistance + gradient resistance + air resistance
・・・・・・■ In this case, rolling resistance and gradient resistance are acceleration ('V
(tl /d t), and the air resistance is the speed V
(It is a function of Ll. Also, the engine characteristics, gear ratio, and inertia resistance of the vehicle are also functions of acceleration. Therefore, the parameter called running resistance (R) is reflected in the initialization control output, and its magnitude is determined according to the following formula 〇. It has been found that the above-mentioned problem can be solved by determining the initialization control output = (objective of the invention) Therefore, the present invention aims at determining the initialization control output as a function of the demands included in the running resistance and the vehicle output shaft torque. The purpose of this is to suppress undershoot and overshoot of the control when constant speed travel is set, thereby stabilizing constant speed travel control. (Means for solving the problem) In order to achieve the above object, the constant speed traveling device for automobiles according to the present invention has a basic conceptual diagram shown in FIG. Then, there is a commanding means C for commanding the setting of constant speed driving control, a deviation calculating means d for calculating the deviation between the target vehicle speed and the current vehicle speed when constant speed driving control is set, and a command means C for commanding the setting of constant speed driving control, When set, the initial value calculation means e calculates the initial control value for constant speed driving based on the speed and acceleration of the vehicle at the time of setting, and when the constant speed driving control is set, the current vehicle speed or target vehicle speed is set. A control means f which calculates a control value for controlling the engine output so as to match the engine output, and determines the control value based on the initial control value when constant speed driving control is set, and a control value based on the output of the control means r. (Operation) In the present invention, the initialization control output is determined based on the set speed and the set acceleration when the constant speed running is set. Since acceleration is a major factor in the running resistance and shaft torque, the initial set output is appropriate for the running conditions, suppressing undershoot and overshoot with respect to the target vehicle speed. ( Embodiment) Hereinafter, the present invention will be explained based on the drawings. Figures 2 to 5 are diagrams showing an embodiment of the constant speed traveling device for automobiles according to the present invention. First, the configuration will be explained. The figure shows the overall configuration of this device, which is roughly divided into a control unit 1 that processes control values for constant speed driving, a sensor group 2 that detects various information, and a throttle unit that adjusts engine output. It is composed of a valve 3 and a throttle operating mechanism 4 that operates the throttle valve 3. The sensor group 2 includes a vehicle speed sensor 11, a main switch 12, a set switch 13, a resume switch 14, a first cancel switch 15, and a second cancel switch 16.
Consisting of The vehicle speed sensor 11 has a function as a vehicle speed detection means, for example, rotates a magnet using a speedometer cable, and outputs a pulse signal proportional to the vehicle speed in combination with a reed switch. The main switch 12 is a switch that is turned on and off as desired by the occupant, and when turned on, supplies the voltage of the battery 17 to the control unit l via the ignition switch (path shown). The set switch 13 is a switch operated by a passenger to instruct constant speed driving, and the resume switch 14 is a switch to return to the original state after constant speed driving is canceled. The first cancel switch 15 and the second cancel switch 16 are switches for canceling the constant speed running set, and these are, for example, a stop lamp switch that is turned on when the brake pedal is depressed, and a stop lamp switch that is turned on when the parking brake is operated. It is configured by using either a parking brake switch that is turned on and a clutch switch that is turned on when the clutch pedal is depressed, either alone or in combination. Each of the switches 13 to 16 constitutes a command means 17. Signals from the sensor group 2 are input to the control unit 1, and the control unit 1 has functions as acceleration detection means, deviation calculation means, initial value calculation means, and control means. And the control unit 1 is C
PtJ21, ROM22, RAM23, clock 24
, an input port 25, an output port 26, a constant voltage circuit 27, and buffer amplifiers 28-30. C.P.
The U21 takes in necessary external data from the input boat 25 according to the program written in the ROM 22, and performs processing necessary for acceleration calculation and constant speed driving control while exchanging data with the RAM 23. The values are processed and the processed data is output to the output port 26 as necessary. The input boat 25 has a sensor group 2.
At the same time, control signals for constant speed running control and fail-safe are inputted from the output port 26 via the bumper amplifiers 28 to 30 to the throttle operating mechanism 4.
is output to. The puffer amplifiers 28 to 30 excite and amplify the signal from the output port 26 to a level at which the throttle operating mechanism 4 can be operated. The clock 24 supplies a predetermined clock signal to each part of the control unit 1, and the constant voltage circuit 27 supplies a predetermined constant voltage to each part of the control unit 1. The throttle operation mechanism 4 includes a vacuum pump 31, a motor 32, an atmospheric air introduction control valve 33, and a failsafe control valve 34.
, filters 35, 36, control passage 37 and pneumatic actuator 38. The motor 32 is started/stopped based on a control signal from the control unit 1, and the vacuum pump 31 rotates under the driving force of the motor 32 to generate a predetermined negative pressure. Atmospheric introduction control valve 3
Reference numeral 3 designates a two-point, two-position solenoid valve, which is in the ff(1) position (position shown in the figure) when no control signal (ON signal) is supplied from the control unit 1, and is in the control passage 37 through the filter 35. Introduce the atmosphere into the On the other hand, when a control signal is supplied, it switches to position f (II) to cut off communication between incoming and outgoing boats. The filter 35 removes dust in the atmosphere, and the same applies to the filter 36. Furthermore, the fail-safe control valve 34 is also a 2-point, 2-position solenoid valve similar to the atmosphere introduction control valve 33, and the control unit 1
When the system holding signal (ON signal) is not supplied from the controller, the controller is in position (1), and air is introduced into the control passage 37 through the filter 36. On the other hand, when the system hold signal is supplied, it switches to the position (■) to cut off communication between the incoming and outgoing boats. In other words, the fail-safe control valve 34 has a fail-safe function for the constant speed driving system, and when the control unit 1 determines that some abnormality has occurred, the throttle operation by this system is stopped when the supply of the system holding signal is cut off. The operation of the mechanism 4 is stopped and the throttle valve 3 is left only to the operation of the accelerator pedal by the occupant. control passage 3
7 communicates with a pressure chamber 39 of a pneumatic actuator 38, and the pressure chamber 39 is connected to a casing 40 and a diaphragm 4.
1. A similar atmospheric chamber 42 is defined on the left side of the diaphragm 41 in the figure, and the atmospheric chamber 42 communicates with the atmosphere. A spring 43 is compressed in the pressure chamber 39, and the diaphragm 41 moves in the left and right directions in the figure due to the force relationship with the atmosphere in the atmospheric chamber 42, depending on the magnitude of the negative pressure supplied to the control passage 37. , the opening degree of the throttle valve 3 provided in the intake passage 45 is adjusted via a link or a wire cable 44. The throttle valve 3 is operated by the throttle operating mechanism 4 in addition to the operation of the accelerator pedal by the occupant, and changes the passage area of the intake passage 45 to adjust the output of the engine. The throttle valve 3 and the throttle operating mechanism 4 constitute an output adjusting means 46. Next, the effect will be explained. FIG. 3 is a flowchart showing a constant speed running control program written in the ROM 22, and this program is executed once every predetermined time (for example, every 100 m5). This program is started when the set switch 13 is turned on while the main switch 12 is on, and its execution is stopped when either of the cancel switches 15 and 16 is turned on. That is, the command means sets and cancels constant speed driving control based on this program. When the program starts, first P, sets the target set flag F.
, is set (Fl""1). Target set flags F and B are flags that indicate whether or not the target vehicle speed Vset is set under a constant speed driving control command. When F,=O, it is determined that the target vehicle speed Vset has not been set yet, and the current vehicle speed Vn is set as the target vehicle speed Vset at P2. The current vehicle speed Vn is calculated in a subroutine described later. Therefore, the vehicle speed Vn at the time when constant speed driving control is set is the target vehicle speed Vset.
becomes. Next, at P, the target set flag F+ is set, and at P4, an ON signal is output to the atmosphere introduction control valve 33 and the fail-safe control valve 34 to turn on each solenoid, and then the process proceeds to P. Hereinafter, for convenience of explanation, the output of the ON signal to the atmosphere introduction control valve 33 and the fail-safe control valve 34 will be expressed as 5OLI-ON and 5QL2-ON, respectively. Through each process of SQL 1-ON and 5QL2-ON, the atmosphere introduction control valve 33 and the fail-safe control valve 34 are both switched to the position (U), and communication between the control passage 37 and the atmosphere is cut off. 5OLI regarding atmospheric introduction control valve 33
The -ON process is for controlling the target vehicle speed to the target vehicle speed Vset at the start of the constant speed cruise control, by creating a negative pressure in the control passage 37 and causing the pneumatic actuator 38 to shift the throttle valve 3 in the opening direction. Further, the process 5OL2-ON regarding the fail-safe control valve 34 is for cutting off the communication between the control passage 37 and the atmosphere to cancel the fail-safe function. Although it is omitted in this program, in the event of a system error, 5OL2
-The above fail-safe function is activated by turning OFF.
System runaway is prevented. On the other hand, when F1=1 at P, jump Pt''''Pa and proceed to P. At P, it is determined whether the initial flag F2 is set. The initial flag F2 is a flag indicating whether or not the forced initial processing of the throttle valve 3 by the output adjusting means 46 has been completed at the start of the constant speed running control. F! When it is -0, the process proceeds to steps after P6 to execute the above-mentioned initial processing, and when F2=1, it jumps to pus for output correction processing. These will be explained below. First, the value of the initial timer T1 is set at Ph.

Determine whether it is [0]. The initial timer T1 corresponds to the operating time of the motor 32 for supplying negative pressure to the pneumatic actuator 38 in order to forcibly operate the throttle valve 3 at the start of the constant speed running control B. That is, the initialization output of the control (see error E described later) is replaced with the operating time of the motor 32. When this routine is executed for the first time, T=O, so P, ~P1° are executed according to the YES command, and from the second time onwards, the NO command is followed until T1=0. When it becomes =0, it moves to P. At P, it is determined whether the current acceleration 9n is positive or negative. Note that the acceleration </n is also calculated in a subroutine described later. When Qn<O, it is determined that the vehicle is in a decelerating state at the start of constant speed driving control, and an initial error E is calculated using P according to the following equation (2). E=K・Vn-9n ・・・・・・■ However, K: constant initial error E is the target vehicle speed Vset and the current vehicle speed V
This corresponds to the deviation from n, and constant speed driving control is performed by adjusting the engine output so that E=O. When setting this initial error E, acceleration is also taken into consideration in addition to the vehicle speed at the time of setting, unlike in the past. The effects resulting from this will be explained in detail later in comparison with a conventional example. Then, P, sets the initial error E as the value of the initial timer T, and P,. Start the motor 32 with (
ON), thereby 5OLI-〇N, 5OL2-
In the ON state, the motor 32 rotates, and negative pressure is supplied to the pressure chamber 39 of the pneumatic actuator 38 through the control passage 37. In the next routine, T+ -E at P.
(T, ≠ 0), so after branching to P and decrementing the value of initial timer T1,
It is determined whether PIZ is T, -〇. TIf-O
When , this routine is repeated, and when 'r, = O, P
13, the motor 32 is turned off. Therefore, at the start of constant speed driving control, the motor 32 rotates in accordance with the initial error E at that time, negative pressure is supplied to the pneumatic actuator 38, and the throttle operation mechanism 4 adjusts the opening degree of the throttle valve 3 to the target vehicle speed. It is adjusted to approach Vset. Then, after the start of the set, the acceleration Qn of the heavy vehicle becomes positive (<7n
≧0), the process proceeds from P to PI4 according to the YES command, sets initial flag F2 in PI4, and ends the initial processing. Thereafter, the routine moves to output correction processing. In addition, the initial timer T is set 3 to 4 times/se.
The book opening routine is carried out at a cycle of approximately 100 m5.
Repeated every ec. ■Force correction processing First, the value of output correction timer T2 is set in PIS.

Determine whether it is [0]. The output correction timer T2 corresponds to the operating time of the motor 32 for constant speed running control after the initial processing is completed. When branching from P to PIS for the first time, T=O, so follow the YES instruction and execute PI6"
``PI4'' is executed, and from the next time onwards, follow the No command until T2-0 is reached, and when Tt'' becomes 0, the process moves to PI again. pea
Then, the vehicle speed deviation Δ between the target vehicle speed Vset and the current vehicle speed Vn is
(2) is calculated according to the following formula (2). ΔV = V n −VseL −■Also, Pl? Now, the current acceleration deviation 9 is calculated according to the following formula 〇. V=Vn V-t・・・・・・■Then, pH
With +, the correction error E is calculated according to the following formula (■). E=to, Δ■to, 9ntoto29 ......■ However, Ko, ni+, Kt: constants When setting the correction error E in this way, vehicle speed deviation ΔV, acceleration 9n, acceleration deviation 9 is used as a parameter. Then, P
At l'l, the overall value IEI of the correction error E is compared with the allowable value A (for example, A=0°5 km/h). When IEI<A, it is within the allowable range, so it is determined that there is no need for output correction, and the process returns; when IEI≧A, P is set for output correction.
Determine whether E is positive or negative at 2°. When E>0, use pzt to set the correction error E as the value of output correction timer T2, and use Pt□ to turn the air introduction control valve 33 to 0FF (SQL 1-
OFF). On the other hand, when E<O, the same process as pzt is performed at Po, and the motor 32 is turned on at P24. In this way, depending on whether the correction error E is positive or negative, SQL 1
- The processing time of OFF or ON of the motor 32 is set alternatively. Then, from the next routine, this set processing time (value of output correction timer T2) is decremented until it becomes zero, and the negative pressure supplied to the pneumatic actuator 38 is controlled.
Throttle valve 3 with pneumatic actuator 38
The opening degree is adjusted to match the target vehicle speed Vset. That is, when the output correction timer TtO value is set to E, since T≠0 in PIS, the timer value T2 is then decremented in pzs, and it is determined in Po whether T2=0. When T2≠0, repeat the routine and T! = 0, turn on the atmospheric introduction control valve 33 with pzt.
At the same time, the motor 32 is turned off. FIG. 4 is a flowchart showing a subroutine for vehicle speed processing. First, the current vehicle speed detected by the vehicle speed sensor 11 is sent to the accumulator of the CPU 21 using Pal.
The previous vehicle speed 7-2 stored in the RAM 23 is rewritten to the previous vehicle speed V7-2 using PffZ. Thereafter, similarly, in P31, the current vehicle speed Vn is replaced with the previous vehicle speed ■, 1-I, and in PI4, the accumulator value ■ is stored as the current vehicle speed Vn at a predetermined address in the RAM 23. As a result, the current vehicle speed ■ is determined as the current data Vn. Then, use the Push button to access RAM23.
The current acceleration 9n stored in the previous acceleration 97
-1, calculate Vn-■, 1-I with Pj&,
This is determined as the current new acceleration 9n and stored in the RAM 23. By executing the above subroutine, vehicle speed Vn and acceleration Qn are calculated. Next, the effects of this embodiment will be compared with the conventional example. First, this embodiment is a method for obtaining an optimum throttle opening proportional to the load torque required when setting constant speed cruise control, and the initialization control output is calculated by the above equation 0. This formula was used because the rolling resistance and air resistance of the vehicle are k.・It is expressed as a speed relationship called V (t), and the differences in gradient resistance, engine output characteristics, and gear ratio are vehicle speed■. This is because it appears as a change (=acceleration) in , so it is expressed as a function of acceleration. Therefore, if we express the driving force F using a functional equation that includes rolling and air gradient, which are the main resistances of vehicle motion, and engine output, gear ratio, etc., which are the main differences in the driving force on the vehicle drive side, the driving force F can be expressed as follows: This will be used as the initial control output. "K V tL) -α(1)...■ Also, the running torque Te in a steady state during constant speed running control is actually equal to the running load T, (Road Load), and is expressed by the following equation (2). However, i: Gear ratio R: Tire radius e: Road Load series K: Road Load offset value
Shown as a table. Figure 5 of Table 1 is a timing chart during initial processing, where Figure 5 (a) shows a flat surface, Figure 5 (b) shows an uphill slope, and Figure 5 (c) shows a downhill slope. There is. When the constant speed running control is set at time t=Q, the initial control output is calculated based on the above formula 0, and the output signal is as shown in the figure and initially corresponds to the reference (opening direction) of the throttle valve 3. It is finely and quickly adjusted, and then adjusted to the return side (closed direction). Therefore, the throttle opening θ is the fifth
The vehicle speed changes as shown in the middle row of the figure, and although the vehicle speed ■ decreases slightly as shown in the upper row, it approaches the target value smoothly. Similarly, initial processing based on equation 0 is performed for uphill and downhill, resulting in less undershoot for uphill and less overshoot for downhill compared to the conventional case. On the other hand, the conventional example corresponding to similar driving conditions is the sixth
Figure 6(a) is flat, Figure 6(b)
is for an uphill slope, and FIG. 6(c) is for a downhill slope. As is clear from each figure, in the past, in order to prevent a drop in vehicle speed when setting, the optimal setting output was determined by tuning according to the accelerator link load and power performance of each vehicle only at the time of setting, and this was fixed. Since it is used as a value, there is not much difference from this example when it is flat, but there is a large undershoot on an uphill slope, and a large overshoot on a downhill slope. This is because even if tuning is performed for each vehicle, and even if the vehicle is of the same grade, the actual vehicle speed executed by the set output will be directly affected by variations in accelerator link load and variations in actuator operation. Conventionally, the output when set is a value that is appropriate on a flat road (l in the figure indicates the initial throttle operation position), so overshooting occurs on downhill slopes and a large drop in vehicle speed occurs on uphill slopes. are doing. On the other hand, in this embodiment, the set output is not a constant value indicated by β as in the conventional case, but is appropriately variable depending on the driving conditions. In this case, running conditions such as running resistance and gradient resistance are fed back to the acceleration 9, and the functions thereof are proportionally approximated. Therefore, if the acceleration 9 is used as the main feedback element, an appropriate initial control output can be obtained for any vehicle. In addition, when performing constant speed driving control, in vehicles with an accelerator set function, the value obtained by multiplying the speed at the time of setting, the acceleration at the time of setting, and a predetermined constant is continuously used as the initial control output. It suffices to use it as a signal, and by doing so, the same effects as in this embodiment can be obtained. (Effects) According to the present invention, since the initial control value for constant speed driving control is calculated based on the speed and acceleration of the vehicle, undershoot and overshoot of the control when constant speed driving control is set can be suppressed. This allows stable constant speed driving control.

[Brief explanation of the drawing]

FIG. 1 is a basic conceptual diagram of the present invention, FIGS. 2 to 5 are diagrams showing an embodiment of a constant speed traveling device for an automobile according to the present invention, FIG. 2 is an overall configuration diagram thereof, and FIG. FIG. 4 is a flowchart showing a subroutine for vehicle speed processing, FIG. 5 is a graph for explaining its operation, and FIG. 6 is a flowchart showing a program for constant speed driving control. Graph for explaining the action, No. 7
The figure is a graph showing the driving characteristics of the vehicle. 1... Control unit (acceleration detection means, deviation calculation means, initial value calculation means, control means), 3... Throttle valve, 11... Vehicle speed sensor (vehicle speed detection means) ), 17・
... Command means, 46 ... Output adjustment means.

Claims (3)

[Claims] (1) a) Vehicle speed detection means for detecting the speed of the vehicle; b)
an acceleration detection means for detecting the acceleration of the vehicle; c) a command means for instructing the setting of the constant speed driving control; and d) calculating a deviation between the target vehicle speed and the current vehicle speed when the constant speed driving control is set. deviation calculating means; e) initial value calculating means for calculating an initial control value for constant speed driving based on the speed and acceleration of the vehicle at the time of setting when constant speed driving control is set; and f) constant speed driving control. When set, a control value for controlling engine output is calculated so that the current vehicle speed matches the target vehicle speed, and when constant speed driving control is set, the control value is determined based on the initial control value. A constant speed traveling device for a motor vehicle, comprising: a control means; and g) an output adjustment means for manipulating the output of the engine based on the output of the control means. (2) A patent characterized in that the control means calculates the control value for constant speed driving based on the control value from the initial value calculating means from immediately after the constant speed driving control is set until the sign of the vehicle acceleration is reversed. A constant speed traveling device for a motor vehicle according to claim 1. (3) The control means uses, as a continuous signal, a calculated value based on the speed and acceleration of the vehicle at the time of setting the accelerator, as the initial control value for the accelerator that offsets the acceleration at the time of setting the accelerator. The constant speed traveling device for automobiles according to item 1.