JPS61229621A - Constant speed travel control device for automobile - Google Patents

Abstract

PURPOSE:To moderate the speed change of a vehicle during an accelerating mode to prevent shocks, etc., by carrying out duty control such that the acceleration of the vehicle is made to be a control object during resuming or acceleration, and an advance compensation is made similar to the speed control of the vehicle to attain a desired acceleration. CONSTITUTION:A constant speed system is composed of a frequency-voltage converter 1 for converting the frequency of a vehicle speed signal into a voltage Vn, a memory 2 for a set vehicle speed VM, an advancing compensating type duty control circuit 3 having a function capable of determining a control duty D, a driver 4 and an actuator 5. In the above-mentioned arrangement, there is added an acceleration mode system composed of an acceleration detector 6, a desired acceleration memory 7 and an advancing compensating type duty control circuit 8. Further, the outputs D, D' of both systems are selected by a change-over switch 9. Further, the switch 9 is changed over from its constant speed side to its acceleration side by a manual acceleration switch 10 which is turned on upon resuming or acceleration.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a constant speed cruise control device for an automobile that automatically maintains a running vehicle speed at a set vehicle speed, and in particular is used to avoid sudden changes in vehicle speed during acceleration mode. It is something to do.

[Conventional technology]

Powered by engine negative pressure, by controlling the on/off duty of the solenoid valve, the negative pressure or atmospheric pressure is supplied to the actuator to adjust the force generated by the diaphragm, and the diaphragm automatically operates the throttle. Conventionally, a constant speed cruise control device (autodrive) for an automobile, which attempts to keep the traveling vehicle speed at a set vehicle speed at all times, determines the control duty D using the following formula.

B In the above equation, Vi is the virtual vehicle speed, T is the advance angle time (advance compensation time), Δt is the vehicle speed sampling period, Vn is the current vehicle speed (currently sampled running vehicle speed) -, V'7-1 is the previous vehicle speed ( (vehicle speed sampled one cycle ago), VM
is the set vehicle speed (set vehicle speed stored in memory), S
D is the set duty corresponding to VM, VB is the control speed width, FIG. 3 is an explanatory diagram of Equation 11, and FIG. 4 is an explanatory diagram of Equation (2).

The virtual vehicle speed Vi compensates for the operation delay of the mechanical system including the actuator, and has the same slope ΔVn/Δt as the straight line (solid line) connecting the current vehicle speed Vn and the previous vehicle speed ■n−+, and the advance angle time T. This is the value on the straight line (dashed line). This value Vi is obtained for each Δ, and is converted into the control duty D by sequentially substituting it into equation (2). Dn in FIG. 4 is the duty at each time point corresponding to Vi, and takes a value from 0 to 100% within the range of the control speed width vB. Qualitatively, when the vehicle speed decreases, the duty increases, and conversely, when the vehicle speed increases, the duty decreases and converges to the set duty.

By the way, in addition to the normal constant speed mode mentioned above, this first drive has resume (return control) and accelerator (
There are two acceleration modes (speed increase control). Resume is control when the constant speed control is temporarily interrupted by stepping on the brake while traveling at a constant speed, and then the vehicle speed is returned to the original set vehicle speed. On the other hand, the accelerator sets the vehicle speed while driving at a constant speed.
This is the control for raising the temperature by 1. Instructions are given by operating a switch.

[Problem that the invention seeks to solve]

However, conventionally, the above equation (1) is used even when resuming.

Since control is performed based on (2), the period during which the control duty D is 100% is long when returning from low-speed running outside the range of the speed control width VB.

Also, when accelerating, the control duty D is unconditionally 100.
%. For this reason, a car with high horsepower accelerates too strongly, giving the driver a sense of shock or anxiety. The present invention attempts to improve this point.

[Means for solving problems]

In the constant speed mode, the present invention compares the current vehicle speed at each point in time with the vehicle speed stored in the memory, and advances and compensates the throttle control actuator so that the current vehicle speed becomes equal to the vehicle speed. In a constant speed cruise control device for an automobile that performs duty control, in acceleration mode, the current acceleration at each point in time is detected, and according to the duty control characteristics for acceleration mode, the current acceleration is detected as the current acceleration increases until the reference duty is reached. The present invention is characterized in that the control duty for the actuator is progressively compensated for and reduced, and after the duty has been reduced to the reference duty, the control duty is maintained at that value and accelerated.

[Effect]

The control target when resuming or accelerating is acceleration,
If duty control is performed so that the target acceleration is achieved while proceeding and compensating in the same way as speed control, the speed change in the acceleration mode becomes gentle, and the driver does not feel shocked or anxious. This will be explained in detail below with reference to the illustrated embodiments.

〔Example〕

FIG. 1 is a block diagram of main parts of a constant speed cruise control device showing an embodiment of the present invention, in which 1 is a frequency-voltage converter that converts the frequency of a vehicle speed signal (proportional to the current vehicle speed) into a voltage Vn; 3 is a memory for the set vehicle speed VM, 3 is a lead compensation type duty control circuit having a function of determining the control duty D from the calculation of equation 11 (21), 4 is a driver, and 5 is an actuator.

The systems 1 to 5 (hereinafter referred to as constant speed mode system) are the main parts of a conventional constant speed traveling control device, and the driver 4 drives the actuator 5 with a pulsed current of control duty D.

In this example, an acceleration mode system consisting of an acceleration detector 6, a target acceleration register ↑, an a device 7, and a lead compensation duty control circuit 8 is added here, and the output duties D and D' of both systems are selected by a changeover switch 9. do. The switch 9 is switched from the constant speed side to the acceleration side by a manual acceleration switch 10 that is turned on when the vehicle is resumed or accelerator. The advance compensation type duty and duty control circuit 8 of the acceleration mode system determines the control duty D' by the following equation.

VB In the above formula, At is the virtual acceleration, T is the advance angle time, At is the sampling time, An is the current acceleration, A n-1 is the previous acceleration, AM is the target acceleration, AB is the control acceleration width, and Do is the reference duty. . The current acceleration An is obtained by dividing the difference Δ■ between the current vehicle speed Vn and the previous vehicle speed V n-1 by the sampling time Δt. The previous acceleration An-1 is the one at the time of the previous sampling of such acceleration. The target acceleration AM is preset to a value lower than the maximum acceleration of the vehicle, and the reference duty Do is set to match it. Therefore, this reference duty Do and the set duty SD in equation (2) are generally different. The virtual acceleration eccentric i is for compensating for the delay of the actuator 5, and the current acceleration An
It has an advance time T. This point is similar to equation (11). Also, the configuration of equation (4) is basically the same as equation (2).

FIG. 2 is a control characteristic diagram of the present invention. This characteristic diagram is for the time of resume, and the vehicle speed ■n is at time t.

After turning on the switch 10, the value decreases for a while, and then increases through the minimum value (An-0). During this period, the acceleration An changes as shown by the solid line toward the target value AM, and thereafter the vehicle speed Vn is returned to the set vehicle speed vM at the target acceleration AM. Accordingly, the control duty D' changes as follows. First, in a state where the virtual acceleration Ai has fallen outside the range of the control acceleration width AB, the control duty D' is set to 1.
Set it to 00%. However, this D' = 100% does not last as long as in the conventional case, and does not cause a large speed change. Then, the acceleration An increases and the virtual acceleration Ai becomes A
When it falls within the range of B, the control duty D' begins to decrease below 100%. This decrease in duty is A n-
Since this continues until A M, the control duty D' based on the virtual acceleration Ai temporarily enters a region below the reference duty Do.

When A n = AM is reached, the control duty D' is then set to the reference duty Do (approximately 70 to 80%), and the vehicle speed Vn is returned to the set vehicle speed VM at the target acceleration AM. Since this resume operation is started by activation by the switch 10, it is necessary to restore the switch 9 internally. For example, lead compensation type duty control circuit 3
An example of this would be to issue a signal to return the switch 9 from the acceleration side to the constant speed side when it is detected that the speed has reached ■n-■M-4K m/h. Also, even if the switch 10 is turned on, the switch 9 is not immediately changed, but if the vehicle speed Vn at that point is, for example, vM~8'm/h or less, the switch is switched to the acceleration side, otherwise it is left at the constant speed side. It is also possible to add control to keep the

On the other hand, when accelerating, the set vehicle speed VM in the memory 2 is updated with the current vehicle speed Vn at each point in time throughout the period when the switch 10 is on.

The change in acceleration in this case is so small that the region in which the vehicle speed Vn decreases in FIG. 2 is replaced by a constant speed traveling region, and quickly reaches the target value AM. Then, the vehicle speed Vn is increased with this target acceleration AM, and when the desired vehicle speed is reached, the switch 1 is turned on.
By turning off 0, the vehicle speed remains in the memory 2 and becomes the set vehicle speed vM from now on. At this time, the switch 9 returns from the acceleration side to the constant speed side in conjunction with the turning off of the switch 10.

It should be noted that whether the instruction given by the common switch 10 is resume or accelerator can be determined logically depending on whether or not the vehicle is currently under control.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to smoothly change speed when resuming or accelerating in constant speed driving control, so there is an advantage that the driver is not shocked or anxious due to sudden acceleration.

In addition, the acceleration mode system also advances and compensates for good responsiveness.

[Brief explanation of drawings]

FIG. 1 is a main part program diagram showing an embodiment of the present invention, FIG. 2 is a control characteristic diagram thereof, and FIGS. 3 and 4 are control characteristic diagrams of a conventional constant speed cruise control system. In the figure, 1 is a frequency-voltage converter, 2 is a set vehicle speed memory, 3 is a constant speed mode advance compensation type duty control circuit,
5 is an actuator, 6 is an acceleration detector, 7 is a target acceleration memory, 8 is a lead compensation type duty control circuit for an acceleration mode system, 9 is a system changeover switch, and 10 is a resume/accelerator switch. ;string) t'l-ltχ ○ Old (昶;bladder λ1 tl'l-1t"0 1 volume @ δ -8 → Zheng 3

Claims (1)

[Claims] In constant speed mode, constant speed driving control for automobiles compares the current vehicle speed at each point in time with the set vehicle speed in the memory, advances the throttle control actuator to compensate, and performs duty control so that the current vehicle speed becomes equal to the set vehicle speed. In the device, in the acceleration mode, the current acceleration at each point in time is detected, and according to the duty control characteristic for the acceleration mode, the control duty for the actuator is progressively compensated and decreased as the current acceleration increases until the reference duty is reached, Furthermore, after the duty is reduced to the reference duty, control is performed so that the value is maintained and acceleration is performed.