JPH0354032A - Constant speed running device - Google Patents

Abstract

PURPOSE:To avoid stepping phenomenon of a vehicle speed by providing a limit value changing means to change a limit value to a larger value than the value at usual control, at least, at either acceleration control or return control. CONSTITUTION:A constant speed running device adjusts opening of a throttle valve 12, by controlling a direct current motor 20 with a microcomputer 30 to which respective output are input from a vehicle speed sensor 34, a set/ deceleration switch 40, a return/acceleration switch 42, an a canceling switch 44. This adjustment of opening is performed following to respective control functions of usual control, acceleration control, or return control. While actual acceleration at each case of control is under a limit value, phase advance compensation control is performed based on the actual acceleration, while over a limit value, the acceleration is fixed on the limit value and phase advance compensation control is performed. In this case, the limit value can be changed to a larger value than that at usual control, at least, at either acceleration control or return control.

Description

[Detailed Description of the Invention] Industrial Application Field This invention is a method for automatically adjusting and maintaining the traveling speed (hereinafter referred to as vehicle speed) of a vehicle equipped with a prime mover, such as a car equipped with an internal combustion engine, at a set vehicle speed. This invention relates to a constant speed traveling device.

The main purpose of conventional technology constant speed traveling devices is to maintain the vehicle speed at a set target vehicle speed, and this control is referred to as normal control. Normally, it is possible to control the Acceleration control is a control that increases the vehicle speed in response to the operation of an operating member by the driver while driving at a constant speed. After the operation of the operating member is completed, the target vehicle speed is maintained at the value at the end of the operation and normal control is performed. be exposed. In addition, after the constant speed driving is temporarily canceled due to a brake operation while driving at a constant speed, normal control is performed based on the target vehicle speed when the constant speed driving is canceled according to the operation of the operating member by the driver. This is the control to return to.

Also during this return control, the target vehicle speed is increased at a predetermined gradient from the actual vehicle speed at the start of the return control to the target vehicle speed at the time when constant speed driving is canceled.

In this constant speed traveling system, in order to prevent a decrease in control accuracy due to delay in the operation of each component, it has been proposed in Japanese Patent Laid-Open No. 61-229621 to perform phase lead compensation control.

The control amount C of the actuator that drives the speed increaser/decelerator for increasing and decelerating the vehicle is determined by the following equation.

Vi-T(V.-V.I)/Δt 10V. ...- (1
)C=(vH-vi)/Vi+Cs...(2)
However, ■i = virtual vehicle speed T: Advance angle time (advance compensation time) ΔL2 vehicle speed sampling period V7: Current vehicle speed (vehicle speed sampled this time) Vl1
-1: Previous vehicle speed (vehicle speed sampled one cycle ago) VA2 Target vehicle speedC. 4: Target control amount V6 corresponding to Va: Control speed width (amount of change in vehicle speed corresponding to the total amount of change in control amount C)? Imaginary vehicle speed V. is assumed to compensate for the delay in the operation of the constant speed traveling device, and is based on the current vehicle speed ■7 and the previous vehicle speed ■. This is a vehicle speed that has the same gradient (V, -Vゎ-1)/ΔL as the straight line connecting V-1 and has a phase that is ahead of the actual vehicle speed by an advance time T. The virtual vehicle speed {circle around (2)} is obtained every ΔL, and the control amount C is determined by sequentially substituting it into equation (2). During normal control, the target vehicle speed VM and the corresponding target control 1c. is kept constant and the vehicle speed is maintained almost constant, and during acceleration control i211 and return control, the target vehicle speed vH is initially rapidly increased by a certain value, and then is increased at a predetermined gradient to increase the vehicle speed. It will be.

In this phase lead compensation control type constant speed traveling device, the above (
Acceleration (Vn-V 1.)/ΔL-ΔV in formula 1)
It is already known to set a limit on fi to reduce the influence of disturbances during vehicle speed detection. For example, when a vehicle speed sensor that detects vehicle speed outputs an output signal with a frequency proportional to the magnitude of the vehicle speed, if the frequency of the output signal increases due to disturbance, it is assumed that the vehicle speed has increased, and (1) and Since the control amount in (2) is calculated, the speed increaser/decelerator is operated and the vehicle speed is changed even though the vehicle speed is not actually changing. Therefore, (1)
By setting a relatively low limit value for the acceleration in the equation, even if the detected value of the vehicle speed fluctuates greatly due to disturbances, the virtual vehicle speed will not follow it as sensitively, and the influence of the disturbances will be kept to a small level. However, if the acceleration is limited to a relatively small value, a step phenomenon will occur in which the vehicle speed changes in a stepped manner during acceleration control (or return control), as shown in Figure 4, causing discomfort and anxiety to the driver. A problem arises that gives a sense of feeling.

If the acceleration limit value is set to a relatively large value, as shown in Figure 5, the step in vehicle speed during acceleration control will be reduced, but the hunting phenomenon will occur for a while after transitioning to normal control. appears.

Further, the effect of disturbance removal due to the limitation of acceleration cannot be sufficiently obtained.

In view of this fact, the present invention makes it possible to sufficiently avoid the influence of disturbances during normal control by making the acceleration limit value different between normal control and acceleration control. The object of this invention is to provide a constant speed traveling device that can reduce the step-up in vehicle speed in at least one of the following.

Means for Solving the Problems And the gist of the present invention is to provide various control functions such as normal control and acceleration control return control, and to control functions based on the actual acceleration while the actual acceleration during each control is below the limit value. In a constant-speed traveling device that performs phase lead compensation control, and when the limit value is exceeded, the acceleration is fixed at the limit value and performs phase lead compensation control, the acceleration limit value is set at least one of the acceleration control and the recovery control. The present invention is provided with a limit value changing means for changing the limit value to a value larger than that during normal control.

Effect: In the constant speed traveling device constructed as described above, the acceleration limit value is set to a small value during normal control;
The influence of disturbances is sufficiently removed, the occurrence of hunting during transition from acceleration control etc. to normal control is well prevented, and the vehicle speed is stably maintained at a constant value. Further, since the acceleration limit value is set to a large value during at least one of the acceleration control and the return control, the occurrence of vehicle speed grading phenomenon can be effectively avoided.

Effects of the Invention Therefore, it is possible to obtain a constant speed traveling device in which the control accuracy in at least one of acceleration control and return control is improved, and in which the influence of disturbances during normal control is small.

Furthermore, if the electric control section of the constant speed traveling device is based on a microcomputer, the limit value changing means can be realized by only slightly changing the control program, or by using a discrete circuit. Even if the
The above effects can be obtained.

EXAMPLE Hereinafter, an example will be described in detail in which the present invention is applied to a constant speed traveling device for an automobile using an internal combustion engine as the prime mover.

In Fig. 2, numeral 10 is an intake pipe, which increases the number of internal combustion engines.
Functions as an accelerator/decelerator to decelerate. The throttle valve l2 of this intake pipe 10 is rotated by a lever 14, and the lever l4 is connected by a link 16 to another lever 18. The lever 18 is attached to the output shaft of a DC motor 20 with a speed reducer, and is rotated approximately 50 degrees in both forward and reverse directions by the DC motor 20. In addition, it is desirable that the reduction ratio of the reduction gear of the DC motor 20 be considerably large, for example, 1/480. The drive circuit 22 of the DC motor 20 is connected to the input/output section 32 of the microcomputer 30.
It is connected to the.

A vehicle speed sensor 34 is connected to the input/output section 32 via a waveform shaper 36. The vehicle speed sensor 34 emits an output signal with a frequency proportional to the vehicle speed, and this output signal is converted into a pulse-like signal by the waveform shaper 36 and supplied to the microcomputer 30. Input/output section 3
2 is also connected to a control switch 38. The control switch 3 has a lever as an operating member, and when this lever is operated in three directions from the neutral position, any one of the set/deceleration switch 40, return/acceleration switch 42, and release switch 44 is closed. R, +Rz, Rl, R+, respectively
A signal corresponding to the combined resistance value of +Rt +R3 is supplied to the computer 30.

In addition to this, the input/output section 32 is connected to various switches for automatically canceling constant speed running, but as these are not directly related to the present invention, their explanations will be omitted.

The microcomputer 30 includes a CPU 50 and a RAM 52.
and ROM 54, and RAM 52 includes a third
As shown in the figure, a working memory is provided along with a memory for storing the current vehicle speed, previous vehicle speed, acceleration, acceleration limit value, target vehicle speed, and the like. In addition, the ROM 54 stores values such as acceleration limit value AB and advance angle time T, as well as control programs. It is. Only the portions of the control program that are closely related to the present invention are extracted and shown in FIG. This part sets the acceleration to different limit values A and B during acceleration control and return control, and during other controls such as normal control, and calculates the limiting amount D of the DC motor 20. , and the sampling time Δt (for example, 5
It is executed every 0msec).

First, step St (hereinafter simply referred to as Sl).

The same applies to other steps), the current vehicle speed Vn is read based on the output signal of the vehicle speed sensor 34, and the acceleration Δvo is calculated in S2. Current vehicle speed V. Using the previous vehicle speed V■1 read last time, ΔV, = (V. Vll-+)/Δt... (3)
The following calculations are performed.

Then, in S3 and S4, it is determined whether acceleration control or return control is in progress.

By executing a program (not shown), the microcomputer 30 determines that an acceleration command has been issued when the return/acceleration switch 42 is turned on during constant speed driving, and resumes/accelerates when the constant speed driving is canceled. When the switch 42 is turned on, it is determined that a return command has been issued, and an acceleration flag and a return flag are set respectively, and in S3 and S4, it is determined whether or not these flags are set. A judgment is made.

If the determinations in S3 and S4 are both No, S5 and S6 are executed, and the absolute value of acceleration is 1ΔV. l
If the value is less than or equal to the limit value A, the value remains unchanged, and if it is greater than the limit value A, it is changed to the limit value A.

In addition, if the acceleration control or return control is in progress, the absolute value of the acceleration is 1ΔV by executing S7 and S8.
If l is larger than limit value B, it is changed to limit value B. The limit value B is selected to be larger than the above limit value A.

S5, 36 or S7, . After executing S8, the virtual vehicle speed Vi is calculated in S9 using the following equation.

V. =T・ΔV. +V, ・ ・ ・ ・ (4) Furthermore, in SIO, control? llI m D is calculated by the following equation.

D=G(V.-V,)= ...- (5) In the equation (5), G is the gain, and when the control amount D is positive, the opening degree of the throttle valve l2 is on the open side, When D is negative, it is controlled to the closed side. The rotation of the DC motor 20 with a speed reducer is controlled based on the control amount D determined by the calculation, and the throttle valve 12 is rotated by an amount commensurate with the control ID, thereby controlling the rotational speed of the internal combustion engine. So, the current vehicle speed ■.

is controlled to approximately the target vehicle speed Vs.

In this embodiment, the vehicle speed is controlled to approximately the target vehicle speed by phase advance compensation control during acceleration control, return control, and other controls such as normal control, but during normal control, acceleration is limited. Since the value is selected to be small, if the output signal of the vehicle speed sensor 34 contains large noise, the acceleration used in the phase lead compensation control is limited, thereby effectively eliminating the influence of the noise. Moreover, since the acceleration limit value is selected to be large during acceleration control in which the vehicle is accelerated and during return control, a stepped phenomenon of vehicle speed as shown in FIG. 4 occurs during acceleration control and return control. Never.

Furthermore, hunting as shown in FIG. 5 does not occur during transition to normal control. S3, S4 of the microcomputer 30. The portion that executes S7 and S8 constitutes a limit value changing means.

In this embodiment, the acceleration limit value is the same during acceleration control and return control, but it is also possible to select different values, and various other modifications may be made. The invention can be practiced in modified forms.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a control amount calculation program in an embodiment of the present invention. FIG. 2 is a diagram schematically showing the structure of the above embodiment, and FIG. 3 is a diagram conceptually showing the structure of the RAM in FIG. 2. FIGS. 4 and 5 are graphs showing the results of experiments conducted prior to the completion of the present invention. l2: Throttle valve 20: DC motor 30: Microcomputer 34: Vehicle speed sensor 38: Control switch 42: Return/acceleration switch

Claims (1)

[Scope of Claims] Normal control that maintains the actual vehicle speed at a set target vehicle speed, and increasing the actual vehicle speed by operating an operating means during constant speed driving and setting the vehicle speed at the end of the operation as the target vehicle speed. Equipped with each control function of acceleration control and return control that returns to the target vehicle speed before cancellation after constant speed driving is canceled, and as long as the actual acceleration during each control is below the limit value, the phase advances based on the actual acceleration. In a constant speed traveling device that performs compensation control and performs phase advance compensation control by fixing acceleration at a limit value when the limit value is exceeded, the limit value of acceleration is set to normal during at least one of acceleration control and recovery control. A constant speed cruise control device comprising a limit value changing means for changing the limit value to a larger value than during control.