JPH07115602B2 - Constant-speed traveling device for automobiles - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant-speed traveling device for vehicles such as automobiles that adjusts the opening of a throttle valve by using, for example, a pneumatic actuator, and in particular, uses the amount of change in acceleration as one parameter. The present invention relates to a constant speed traveling device that determines a control output and intends control stability. (Prior Art) Recently, ASCD (Auto Speed Control Device) has been developed and put into practical use as a system that can be automatically set to the traveling speed of the vehicle. In such a system, stability of control is important, This leads to a sense of security for the driver. As a conventional constant-speed traveling device for an automobile of this type, there is, for example, one described in Japanese Patent Laid-Open No. 61-30430. In this device, when the vehicle is set for constant speed running, the air pressure in the pressure chamber of the actuator is controlled so as to reach the set vehicle speed according to the running conditions, and the diaphragm is operated, thereby adjusting the opening of the throttle valve. There is. Therefore, the negative pressure and the atmospheric pressure introduced into the pressure chamber are controlled to change the throttle valve opening, and as a result, the engine output is adjusted and the vehicle speed is controlled to be equal to the set vehicle speed. (Problems to be Solved by the Invention) However, in such a conventional vehicle constant-speed traveling device, a control amount is determined using the deviation of the vehicle speed and the acceleration of the vehicle as parameters, and the actuator is based on this control amount. Since the engine pressure is controlled by controlling the air pressure in the pressure chamber, there is a predetermined time lag between the parameter detection timing and the control target (engine output) response timing. In the feedback control system having such a time delay, the time delay can be complemented by setting the amplification degree of the system higher.
On the other hand, a high amplification degree causes a vibration phenomenon such as a damping vibration or a divergent vibration in the course of control, and makes the control operation extremely unstable.
For example, when a so-called disturbance occurs in which the road surface gradient resistance or the like changes under constant speed traveling, a predetermined control output is output from the control system in order to correct the decrease in vehicle speed due to this disturbance. At this time, if the amplification degree of the control system is low, the return to the target vehicle speed will be delayed, and if the amplification degree is too high, the recovery time will be short, but the above-described vibration phenomenon will occur and the stability will be deteriorated. Therefore, when selecting the amplification degree, there is no choice but to use a value that avoids the vibration phenomenon, and the response speed of the control system is not sufficiently improved. Further, since the amplification degree for avoiding the vibration phenomenon is closely related to the constituent elements of the control system, it is necessary to tune for each vehicle type, which causes a problem in cost. (Object of the Invention) Therefore, the present invention focuses on that the amount of change over time of the acceleration of the vehicle (hereinafter referred to as jerk) shows a large change tendency in the initial state at the time of divergence in the deviation state of the vehicle speed and at the end of the convergence. However, by adding this jerk to the control parameters, the purpose is to avoid the vibration phenomenon of the system, further speed up the response speed of the control system, and significantly improve the stability of constant speed traveling control. There is. (Means for Solving Problems) In order to achieve the above-mentioned object, the vehicle constant speed traveling device according to the present invention has a vehicle speed detecting means a for detecting the speed of the vehicle as shown in the basic conceptual diagram of FIG. , An acceleration detecting means b for detecting the acceleration of the vehicle, a command means c for instructing a shift to constant speed running control, and a deviation between the target vehicle speed and the current vehicle speed when shifting to the constant speed running control. Deviation calculation means d
And a jerk calculation means e that calculates the amount of change in acceleration when the vehicle is moving to constant speed running control, and a deviation in vehicle speed and an amount of change in acceleration and acceleration when the vehicle is moving to constant speed running control. Based on the control value calculation means f, which calculates a control value for controlling the engine output so that the current vehicle speed matches the target vehicle speed, and the output adjustment means g, which operates the engine output based on the output of the control value calculation means f. , Are provided. (Operation) In the present invention, the jerk which shows a large change tendency in the initial stage of divergence and the final stage of convergence in the deviation state of the vehicle speed is one of the control parameters. Therefore, when the actual vehicle speed is diverging from the target value in the direction of separation,
The parameter acts as an active component and quickly returns the vehicle speed to the target value. On the other hand, at the time of convergence when the actual vehicle speed approaches the target value, the parameter acts as a negative component and relaxes the convergence curve. That is,
At the time of divergence, the response speed is increased by performing the same action as in the state where the amplification degree of the control system is set to a higher value, and when the vehicle speed is speeding up, the same action as in the state where the amplification degree is reduced is converged. The operation is made reliable, and these stabilize the control under constant speed running. (Example) Hereinafter, the present invention will be described with reference to the drawings. 2 to 10 are views showing an embodiment of a vehicle constant speed traveling device according to the present invention. First, the configuration will be described. FIG. 2 is a diagram showing the overall configuration of the present device. The present device is roughly divided into a control unit 1 for calculating a control value for constant speed traveling, a sensor group 2 for detecting various information, and an engine output adjusted. And a throttle operating mechanism 4 for operating 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. The vehicle speed sensor 11 has a function as vehicle speed detecting means, and rotates a magnet by a speedometer cable, for example, and outputs a pulse signal proportional to the vehicle speed in combination with a reed switch. The main switch 12 is a switch arbitrarily turned on / off by an occupant, and when turned on, supplies the voltage of the battery 17 to the control unit 1 via an ignition switch (not shown). The set switch 13 is a switch for instructing constant speed traveling operated by an occupant, and the resume switch 14 is a switch for returning to the original state after the constant speed traveling is canceled. The first cancel switch 15 and the second cancel switch 16 are switches for canceling the constant speed traveling set, and these are, for example, a stop lamp switch that is turned on when the brake pedal is depressed, and a control operation of the parking brake. A parking brake switch that is turned on and a clutch switch that is turned on when the clutch pedal is depressed are used alone or in combination. The switches 13 to 16 are command means 17
Make up. A signal from the sensor group 2 is input to the control unit 1, and the control unit 1 has a function as an acceleration detecting means, a deviation calculating means, a jerk calculating means and a control value calculating means. The control unit 1 is composed of a CPU 21, a ROM 22, a RAM 23, a clock 24, an input port 25, an output port 26, a constant voltage circuit 27 and buffer amplifiers 28-30. The CPU21 fetches external data required from the input port 25 according to the program written in the ROM22, and exchanges data with the RAM23, while processing values required for acceleration calculation and constant-speed running control. Is processed, and the processed data is output to the output port 26 as needed. The signal from the sensor group 2 is input to the input port 25, and the output port 26
Control signals for constant speed running control and fail-safe are sent from the throttle operation mechanism 4 via buffer amplifiers 28 to 30.
Is output to. The buffer 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 operate. 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. The throttle operating mechanism 4 is a vacuum pump 31, a motor 3
2, atmosphere introduction control valve 32, fail-safe control valve 3, filters 35, 36, control passage 37 and pneumatic actuator 3
It is composed of 8. The motor 32 starts / stops based on a control signal from the control unit 1, and the vacuum pump 31 receives the driving force of the motor 32 and rotates to generate a predetermined negative pressure. The atmosphere introduction control valve 33 is a 2-port 2-position solenoid valve, which is in the position (I) position (illustrated position) when the control signal (ON signal) is not supplied from the control unit 1 and passes through the filter 35 to control the passage. Atmosphere is introduced into 37. On the other hand, when the control signal is supplied, the position is switched to the position (II) and the communication of the access port is cut off. The filter 35 removes dust in the atmosphere, and the same applies to the filter 36. Also,
The fuel-safe control valve 34 is the same as the atmosphere introduction control valve 33.
This is a solenoid valve at the position of port 2 and is in the position (I) position when the system holding signal (ON signal) is not supplied from the control unit 1 and the filter 36
Atmosphere is introduced into the control passage 37 through. On the other hand, when the system hold signal is supplied, the communication is switched to the position (II) and the communication of the in / out port is cut off. That is, the fail-safe control valve 34 has a fail-safe function for the constant speed traveling system, and when the control unit determines that some abnormality has occurred, if the supply of the system holding signal is cut off, the throttle operating mechanism by the present system. The operation of No. 4 is stopped and the throttle valve 3 is left only to the operation of the accelerator pedal by the occupant. The control passage 37 communicates with the pressure chamber 39 of the pneumatic actuator 38,
The pressure chamber 39 is defined by a sourcing 40 and a diaphragm 41. A similar atmosphere chamber 42 is on the left side of the diaphragm 41 in the figure.
And the atmosphere chamber 42 communicates with the atmosphere. A spring 43 is contracted in the pressure chamber 39, and the diaphragm 41 moves in the left-right direction in the figure due to the force relationship with the atmosphere in the atmosphere chamber 42 according to the magnitude of the negative pressure supplied to the control passage 37. The opening of the throttle valve 3 provided in the intake passage 45 is adjusted via the link 44. Throttle valve 3
Is operated not only by the operation of the accelerator pedal by the occupant but also by the throttle operating mechanism 4, and the passage area of the intake passage 45 is changed to adjust the output of the engine. The throttle valve 3 and the throttle operating mechanism 4 are output adjusting means 46.
Make up. Next, the operation will be described. FIG. 3 is a flow chart showing a program for constant speed traveling control written in the ROM 22, and this program is executed once every predetermined time (for example, every 100 ms). 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 any of the cancel switches 15 and 16 is turned on. That is, the command means sets or cancels the constant speed traveling control based on this program. When the program is started, first the target set if a flag F ₁ is set (F ₁ = 1 or) with P ₁ determines whether. This target set flag F ₁ is the target vehicle speed Vset under the constant speed running control command.
Is a flag indicating whether or not was set. F ₁ = 0
At this time, it is determined that the target vehicle speed Vset is not yet set, and the current vehicle speed Vn is set as the target vehicle speed Vset at P ₂ . The current vehicle speed Vn is calculated by a subroutine described later. Therefore, the vehicle speed Vn at the time when the constant speed traveling control is set becomes the target vehicle speed Vest. Then, set the target set flag F ₁ in P _3, the process proceeds to P ₅ after the air introduction control valve 33 and the fail-safe control valve 34 and outputs an ON signal to each solenoid ON when P _4. Hereinafter, for convenience of description, the output of the ON signal to the atmosphere introduction control valve 33 and the fail-safe control valve 34 will be referred to as SOL1-ON and SOL2-ON, respectively. Atmosphere introduction control valve 33, by each processing of SOL1-ON, SOL2-ON,
All the fail-safe control valves 34 are switched to the position (II), and the communication between the control passage 37 and the atmosphere is shut off. The process of SOL1-ON for the atmosphere introduction control valve 33 controls the target vehicle speed Vset at the start of the constant speed traveling control. This is for shifting.
Further, the process called SOL2-ON for the fail-safe control valve 34 is for disconnecting the communication between the control passage 37 and the atmosphere to release the fail-safe function. Although omitted in this program, SOL2-
When it is turned off, the fail-safe function described above is exerted and system runaway is prevented. On the other hand, if P ₁ is F ₁ = 1 then P ₂
~ Jump to P ₄ and go to P ₅ . Initial flag F ₂ in P _5, it is determined whether it is set. The initial flag F ₂ is a flag indicating whether or not the compulsory initial process of the throttle valve 3 by the output adjusting means 46 is completed at the start of the constant speed traveling control. F ₂
When = 0, the above-mentioned initial processing is executed, so the processing proceeds to steps after P ₆ , and when F ₂ = 1 is set for output correction processing.
Jump to P ₁₅ . These will be described below in some cases. Initial process First, the value of the initial timer T ₁ in P ₆

It is determined whether it is [0]. The initial timer T ₁ corresponds to the operating time of the motor 32 for supplying a negative pressure to the pneumatic actuator 38 for forcibly operating the throttle valve 3 at the start of the constant speed traveling control. 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 first executed, T ₁ = 0.
Perform ₇ to P _10, the second and subsequent accordance NO instruction until T ₁ = 0, proceeds to P ₇ becomes to T ₁ = 0. Positive In P ₇ This acceleration n, determines negative. The acceleration n is also calculated in a subroutine described later. When n <0, it is determined that the vehicle speed is in a decelerating state at the start of the constant speed traveling control, and the initial error E is calculated in P ₈ according to the following equation. E = K ・ Vn ・ n ・ ・ ・ However, K: constant initial error E corresponds to the deviation between the target vehicle speed Vset and the current vehicle speed Vn, and the engine output is adjusted so that E = 0 and the constant speed is adjusted. Travel control is performed. Next, the initial error E is set as the value of the initial timer T ₁ at P ₉ , and the motor 32 is started (ON) at P ₁₀ . This allows the motor 32 to be turned on with SOL1-ON and SOL2-ON.
The pneumatic actuator through the control passage 37
Negative pressure is supplied to the pressure chamber 39 of 38. In the next routine
In P ₆ , the situation is that T ₁ = E (T ₁ ≠ 0), so P
_After branching to ₁₁ , the value of the initial timer T ₁ is decremented, and then it is determined at P ₁₂ whether T ₁ = 0. When T ₁ ≠ 0, this routine is repeated. When T ₁ = 0, the motor 32 is turned off at P ₁₃ . Therefore, at the start of the constant speed traveling control, the motor 32 rotates according to the initial error E at that time, the negative pressure is supplied to the pneumatic actuator 38, and the opening degree of the throttle valve 3 is set by the throttle operating mechanism 4 to the target vehicle speed. Adjusted to approach Vset. If the vehicle acceleration n becomes positive (n ≧ 0) at the time when the vehicle speed decelerated once after the start of the setting matches the target vehicle speed, from P ₇
Follow the YES command to proceed to P ₁₄ , and at P ₁₄ the initial flag F ₂
To complete the initial processing. After that, the routine proceeds to output correction processing. The initial timer T ₁ is set at a cycle of about 3 to 4 times / sec, during which this routine is repeated every 100 msec. The output correction process, first, the value of the output correction timer T ₂ at P ₁₅

It is determined whether it is [0]. The output correction timer T ₂ corresponds to the operating time of the motor 32 for the constant speed traveling control after the end of the initial process. Since when first branches to P ₁₅ from P ₅ is T ₂ = 0, executes the P ₁₆ to P ₂₄ according YES instruction, in accordance with NO instructions until the T ₂ = 0 from the next time, T ₂ = 0 Again when
Move to P ₁₆ . At P ₁₆ , the vehicle speed deviation ΔV between the target vehicle speed Vset and the current vehicle speed Vn is calculated according to the following equation. ΔV = Vn-Vset ...... Further, aging of the acceleration n of the vehicle in accordance with the following equation in P ₁₇ (hereinafter, referred to as jerk) is calculated. = N- _n-1 ...... However, _n-1: previous value then calculates a corrected error E according to the following equation at P _18. E = K ₀ ΔV + K ₁ n + K ₂・ ・ ・ However, K ₀ , K ₁ , K ₂ : constant When setting the correction error E in this way, the vehicle speed deviation Δ
In addition to V and acceleration n, jerk, which is the point of the present invention, is used as a parameter. The effect of this jerk will be described later in detail in comparison with the conventional example. Next, at P ₁₉ , the absolute value | E | of the correction error E is compared with the allowable value A (for example, A = 0.5 km / h). | E | <returns it is determined that there is no need for output correction because it is within the allowable range when the A, | E | when the ≧ A positive E at P ₂₀ for output correction,
Distinguish negative. When E> 0, output correction timer T ₂ at P ₂₁
Set the correction error E as the value, the ambient air intake control valve 33 and OFF (SOL1-OFF) at P _22. On the other hand, when the E <0 was treated in the same manner as P ₂₁ in P _23, the motor 32 ON when P _24. In this way, depending on whether the correction error E is positive or negative,
The processing time of SOL1-OFF or motor 32 ON is set alternatively. Then, from the next routine, the setting processing time (value of the output correction timer T ₂ ) is decremented until the supply negative pressure to the pneumatic actuator 38 is controlled, and the pneumatic actuator 38 controls the throttle valve 3. The opening is adjusted to match the target vehicle speed Vset. That is, when the value of the output correction timer T ₂ is set to the correction error E, T ₂ ≠ 0 at P ₁₅ , so the timer value T ₂ is decremented at P ₂₅ , and T ₂ = 0 at P _26.
Or not. When T ₂ ≠ 0, the routine is repeated. When T ₂ = 0, the atmosphere introduction control valve 33 is turned on and the motor 32 is turned off at P ₂₇ . FIG. 4 is a flowchart showing a subroutine of vehicle speed processing. First, at P ₃₁ , the current vehicle speed detected by the vehicle speed sensor 11 is taken into the accumulator of the CPU 21 as V _A , and at P ₃₂ , the previous vehicle speed V _n-1 stored in the RAM ₂₃ is set to the vehicle speed V _{n-2 two} times before. rewrite. Hereinafter, similarly replace the current vehicle speed Vn to the last vehicle speed V _n-1 by P _33, and is stored at a prescribed address of RAM23 vehicle speed V _A as the current vehicle speed Vn at P _34. As a result, the current vehicle speed V _A is obtained as the current data V n. Then, replace the current acceleration n stored in the RAM23 in P ₃₅ to the previous acceleration _{n-1, Vn-V n} -1 by P ₃₆
Is calculated, and this is calculated as the new acceleration n this time, RA
Store in M23. The vehicle speed Vn and the acceleration n are calculated by executing the above subroutine. Next, the effect of this embodiment will be compared with the conventional example. First, the problems in the conventional example will be considered based on FIGS. Generally, in a feedback control system, the time delay of the system is an important factor in determining the response speed of the system. That is, in the loop from the detection of the constant speed traveling control to the operation, there is a delay in the operation of the actuator and a predetermined time delay from the fuel supply to the generation of the engine output. This time delay is recognized as a time from the output of the control output until the actual vehicle speed changes, that is, a so-called time lag. On the other hand, for the purpose of constant speed running control,
It is desirable to match the actual vehicle speed to the target value as quickly as possible. For that purpose, it is conceivable to set the amplification degree of the control system to a high value to increase the control output and accelerate the changing speed of the engine output. That is, as shown in FIG. 5 (b), when a disturbance represented by a variation in road surface gradient resistance, air resistance, or wheel rolling resistance is applied to the control target, the engine output becomes insufficient, and the engine output becomes insufficient. As shown in a), the actual vehicle speed deviates from the target value and tends to decrease (so-called divergence). Since FIGS. 5 (a) to 5 (d) are examples in which the amplification degree of the control system is set high, the control output rapidly rises to operate the actuator as shown in FIG. 5 (d). As shown in FIG. 7C, the throttle opening is opened widely. As a result, the amount of fuel is increased, the engine output is increased, and the actual vehicle speed quickly rises toward the target value. However, since there is a time lag as described above between the control output and the change in the actual vehicle speed, the engine output continues to increase even after the actual vehicle speed reaches the target value, and then falls after the time lag has passed. Move to. Therefore, as shown in FIG. 7A, damping vibrations oscillated up and down around the target value or, in the worst case, divergence vibrations occur and the stability deteriorates significantly. Further, in such a control system in which the amplification degree is set to be high, the stability is similarly deteriorated even when the vehicle speed is increasing and the vehicle speed is directed toward the target value. That is, as shown in FIGS. 6A to 6C, when the actual vehicle speed is directed to the target value (set vehicle speed), the control signal is output in the direction to deactivate the actuator, and the throttle opening is delayed by the time lag. The degree changes. As a result, the control signal is inverted when the actual vehicle speed has not reached the target value,
After several vibrations, speed collection is completed. On the other hand, if the amplification degree of the control system is set low in consideration of such a problem, the occurrence of vibration is avoided as shown in FIGS. 7 and 8, but this time the response speed becomes slow and the stability becomes unstable. Getting worse. Therefore, looking at the time-dependent change amount (acceleration speed) of acceleration, which is the point of interest of the present invention, with reference to FIG. 9 (c), the jerk speed is a large change amount between the eros immediately after the occurrence of the disturbance. In addition, a large amount of change is similarly exhibited between the vehicle speed at which the vehicle speed is approaching the speed control, and the polarity is reversed. That is, by using this jerk as a part of the control parameter, a composite waveform as shown in FIG. 7D is obtained, which rapidly increases the engine output in the initial stage of the disturbance and, at the time of collecting speed, The actual vehicle speed can be smoothly matched to the target value. That is, according to this embodiment,
As shown in FIG. 10, the decrease in the actual vehicle speed due to the disturbance is promptly recovered, the vehicle speed is smoothly collected, and the stability of the constant speed traveling control is significantly improved. (Effect) According to the present invention, since the jerk that shows a large change tendency at the end of divergence and at the end of convergence in the deviation state of the vehicle speed is added to the control parameter, it is possible to avoid the vibration phenomenon of the control system. In addition, the response speed of the system can be accelerated to significantly improve the stability of the constant speed traveling control.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of the present invention, FIGS. 2 to 10 are diagrams showing one embodiment of a vehicle constant speed traveling device according to the present invention, FIG. 2 is an overall configuration diagram thereof, and FIG. FIG. 4 is a flow chart showing a program for the constant speed traveling control, FIG. 4 is a flow chart showing a subroutine program for the vehicle speed processing, and FIG.
FIGS. 6 (a) to 6 (d) are timing charts showing the action at the time of divergence in the conventional control system with increased amplification in order to explain the action, and FIGS. 6 (a) to 6 (c) explain the action. FIG. 7A to FIG. 7A are timing charts showing the action at the time of convergence in the conventional control system with increased amplification degree.
(D) is a timing chart showing the action at the time of divergence in the conventional control system in which the amplification degree is reduced to explain the action, and FIGS. 8 (a) to (c) are conventional timing charts to explain the action. 9A to 9D are timing charts showing the action at the time of convergence in the control system in which the amplification degree of FIG.
Is a timing chart for explaining its action, No. 10
(A)-(d) is a timing chart for clarifying the effect. 1 ... Control unit (acceleration detection means, deviation calculation means, jerk calculation means, control value calculation means), 3 ... Throttle valve, 11 ... Vehicle speed sensor (vehicle speed detection means), 17 ... Command means, 46 ...... Output adjustment means.

Claims (1)

[Claims] 1. A) vehicle speed detection means for detecting the speed of the vehicle; b) acceleration detection means for detecting the acceleration of the vehicle; c) command means for instructing a shift to constant speed running control; and d) constant. Deviation calculation means for calculating the deviation between the target vehicle speed and the current vehicle speed when shifting to high speed traveling control; and e) jerk that calculates the amount of change in acceleration when shifting to constant speed traveling control. And f) calculating a control value for controlling the engine output so that the current vehicle speed matches the target vehicle speed on the basis of the deviation of the vehicle speed and the acceleration and the amount of change in the acceleration when the vehicle is shifting to the constant speed running control. A constant-speed traveling device for an automobile, comprising: a control value calculating means for performing: g) an output adjusting means for operating an engine output based on an output of the control value calculating means.