JPH0431135A - Constant speed travel controller for vehicle - Google Patents

Abstract

PURPOSE:To make convergence on a target car speed constant at all times in spite of a travel load change, and conduct an excellent constant speed travel control, by giving a standard model showing a desired response, and renewing control gain parameters by one in order according to a travel load during travel. CONSTITUTION:An actual car speed is read by means of a car speed detection means 11, and also an actual car speed at the time of being set by means of a target value setting means 12, is set as a target car speed. And so as to reduce a variation between the actual car speed and the target car speed to zero, the quantity of control to an actuator 16 is calculated on the basis of the above variation by means of a control quantity operation means 13, and the opening of throttle valve 17 is operated. A control gain at this time is given in order by means of a gain renewal means 14 on th basis of the actual car speed and a throttle valve opening value detected by means of a travel load detection means 15, and a control quantity is calculated at all times. That is, a stable control gain is calculated and renewed in order at every travel load change by means of a travel load change quantity during a constant speed travel and the control rules of time/delay/control.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a constant speed cruise control device for a vehicle.

Conventional technology A conventional constant speed cruise control device for a vehicle detects the actual vehicle speed with a vehicle speed sensor, sets a target vehicle speed according to the will of the driver, and performs P I-PD control or I so that the actual vehicle speed converges to the target vehicle speed. - Performs feedback 11 such as PD control. At this time, changes in running load (L, that is, changes in slope,
Due to changes in air resistance, etc., the dynamic characteristics of the vehicle change, and the convergence to the target vehicle speed is not always constant but varies. Therefore, in order to achieve a constant convergence to the target vehicle speed regardless of changes in the running load, multiple control gains are applied in response to changes in the running load to calculate the amount of operation to the actuator that drives the throttle valve. This adjustment requires a great deal of effort. For example, as described in Japanese Patent Application Laid-Open No. 1153344, the amount of operation to the throttle valve is calculated using P+I-P+D control, and the running load is calculated based on the difference between the current throttle opening and the throttle opening required for steady driving on flat ground. According to this increase in running load, increase the proportional constant and integral constant of the forward-facing control system P+I, and decrease the proportional constant and differential constant of the negative feedback control system P+D to reach the target vehicle speed regardless of the difference in running load. Keeping the convergence of
We are trying to achieve good constant speed driving control.

Problems to be Solved by the Invention However, in conventional constant speed cruise control devices based on feedback control such as P+I-P+ control, as the control gain is changed according to the running load, The balance of the entire control system is lost and the system is likely to become unstable. For each control gain of the above control system,
Each of them is closely related, and if one of the gains, e.g.
As stated in the above-mentioned publication, if only the control gain in the negative feedback differential term is changed, it will be difficult to obtain the desired response waveform unless the gains of other proportional terms and the gain of the forward-looking control system are also changed. The K system as a whole may become unstable due to even the slightest disturbance, so as stated in the above-mentioned publication, all control gains are changed to account for all possible changes in running load during constant speed driving. for,
In order to obtain the optimum control gain that is always stable and provides the desired response, it is necessary to determine all gains in a well-balanced manner. It cannot be determined quantitatively, but only qualitatively. Therefore, this gain determination work is difficult in such a feedback control system, and it is possible to cut it through experimental work.・I had to decide by trial and error.
Moreover, it is very difficult to always obtain a control gain with good performance.The present invention was made by focusing on the above-mentioned conventional problems. Introducing the concept of adaptive control that estimates unknown terms, that is, time delay control, is used to detect changes in vehicle dynamic characteristics due to changes in running load. Therefore, by sequentially updating the calculated control gain in response to disturbances such as slopes, L It is an object of the present invention to provide a constant speed cruise control device for a vehicle that can realize constant speed cruise control with high precision. A vehicle speed detection means for detecting the actual vehicle speed, a target value setting means for setting the target vehicle speed according to the driver's will, and a control amount for the actuator that drives the throttle valve so that the actual vehicle speed matches the target vehicle speed. A control amount calculation means that calculates the vehicle speed detected by the detection means and the target vehicle speed according to the time delay control control law, a means for detecting a change in the running load during driving, and the running load detection means. and gain updating means for sequentially calculating the control gain of the time delay control according to the detected value of the running load detecting means and updating the control gain to that value.

The present invention uses the above-mentioned configuration to calculate a stable control gain every time the running load changes, based on the amount of change in the running load during constant speed driving and the control law of time delay control, and update it sequentially. , it is possible to calculate the control amount to the actuator so that the convergence to the target vehicle speed is always constant without being affected by fluctuations in the running load.
It is stable and has good convergence (＼Constant speed running control can be performed.Example: In the following, the vehicle target is an automobile.The embodiment of the present invention will be explained based on the drawings. The system configuration and control system configuration will be described below. Fig. 1 is a configuration diagram conceptually showing an embodiment of the present invention. The actual vehicle speed is read by the vehicle speed detection means 11 and the target value setting means 12. , the actual vehicle speed at the time of setting is set as the target vehicle speed.Then, the deviation is calculated by the control amount calculation means 13 so that the actual vehicle speed is equal to the target vehicle speed, that is, the deviation between the actual vehicle speed and the target vehicle speed is zero. Based on this, the control amount to the actuator 16 is calculated and the opening of the throttle valve 17 is operated.The control gain at this time is updated based on the throttle valve opening value detected by the running load detection means 15 and the actual vehicle speed. The control amount is sequentially given by the means 14, and an appropriate control amount is always calculated.

FIG. 2 is a control block diagram of the above-described embodiment. Based on this diagram, the control concept of time delay control (TDC), which is a type of adaptive control, will be explained. The actuator 16 operates the throttle valve 1 according to the target opening input U.
Adjust the opening degree of 7 to control the vehicle speed. This vehicle speed V
The target value setting means 12 sets the actual vehicle speed read and set by the vehicle speed detection means 11 as the target vehicle speed R.
Model 131 i-table Actual vehicle speed V (gives the desired response waveform when converging to the target vehicle speed R,
Outputs the target track vehicle speed Vm at that time 4 TDC so that the deviation e between the target track vehicle speed Vm and the actual vehicle speed V becomes zero.
The control amount U to the actuator 16 is calculated by the control formula 132, and by the above operations, it is possible to perform speed control that follows the actual vehicle speed v75<the target vehicle speed R with desired response characteristics.

Here, the control gain for calculating the control amount U is set using the following procedure. First, the running load is calculated by the running load calculation means 151 based on the throttle opening amount detected by the throttle opening detection 152 and the actual vehicle speed V in each control cycle.

Then, according to this value, a new control gain is calculated and automatically updated by the gain updating means 14 one after another. Then, using this updated control gain, a control input that is always stable and has constant convergence is calculated. next
Control system design for time delay control, and
We will explain how to derive a stable control gain according to the running load.

First, input the target opening degree to the throttle valve 17 by U (
S) and the actual vehicle speed is its output V(S), then the transfer function G(S) during this time is given by the following equation.

Next, time delay control (hereinafter referred to as TDC)
The control system design will be explained below. This is a controller that is effective for systems with unknown dynamic characteristics, and below we will explain how to obtain a control law that follows a reference model for a nonlinear plant.
L, Youcef-Toumi, and I
to, O1'On Model Reference
ControlUsing Time Delay f
or Non1inear Systems with
Unknown Dynamics'M, 1. T,Re
port LMP/RBT 86-06゜June,
1986. Even if the details are given in Equation (1), first converting equation (1) into the time domain gives V(t)−−a V(t)+bLI(t)
(2) Assume that a and b are unknown and the fluctuation range is known as follows.

0 < amin < a < amax
(3) 0 < bmin < b
< bmax (4) Also
The stable class normative model is given by the following equation.

Vm(t)=-amVm(t)+bmR(t>am
,brn>0 (5) Next, the standard error model is given by the following equation.

e (t) --(am1K)e (t)
am+K>O(6) just L e (t)-V
m(t)-V(t) (7) Here, K is an error feedback gain, and desired error dynamics can be obtained by appropriately selecting the error feedback gain K.

When the relationship in equation (6) is derived from equations (2), (5), and (7), the following equation is obtained.

e --am e -amV+bmR+a V-b
U (8)amV+bm
R+ a V-b U--K e
(9) Therefore, control human power U such that equation (9) holds true
By giving , it is possible to obtain a response that satisfies equation (6).

That is, the control input can be given using the following equation.

U= b −' (−amV+bmR+a V×K e
) (10) However
In the above equation, unknown variables a and b are included, and it is impossible to determine the control human power U as it is. Therefore, when thinking about estimating this unknown part, we first write equation (2) as follows. It is divided into unknown part aV and other parts as shown in FIG.

a v--v+ b U
(11) Here, L is a minute time delay and L
Assuming that aV-h is as follows.

h(t)+h(t-L) (
12) From equations (11) and (12), the unknown term is estimated using the following equation.

h(t)-V(t-L)+b U(t-L)
(13) By substituting this estimated value into equation (lO), the control law for time delay control regarding constant speed running control is given by the following equation.

U(t)-U(t-L)+b-+fJ/(t-L)
amV(t)+bmR+Ke]
(14) However, since the equation (14) for calculating the control human force U includes G1, the unknown term b, it is impossible to determine the control human force U(t) to the actuator II~ Therefore, the control By substituting the system force (estimated value b such that it becomes stable) into equation (14), the actual control input is obtained. That is, the control input is given by the following equation.

U(t)-U(t-L)+b-'(-V(t-L)
-amV(t)+bmR+Ke) b>O(
15) FIG. 3 is a block diagram showing in detail the control law given by equation (15). When a certain control human power U is given to the controlled object 31, a vehicle speed V is output. The model 33 inputs the target vehicle speed R and outputs the target track vehicle speed Vm. The time delay controller 32 is configured by the deviation e between Vm and V, the target vehicle speed R, the actual vehicle speed V, and each of the above parameters, and the control human power U to be applied to the controlled object o1 is calculated so that the deviation e becomes zero. Ru.

Cocote, -V(t-L), U(t-L) is the unknown part cancellation term of L furan h, -amp(t)+bm
R1& is the dynamic characteristic insertion term Kei of the reference model and the error feedback class.

Next, we will explain how to derive the estimated value that makes the entire control system stable.

First, when formula (15) is rearranged using Laplace variable ML, the following formula is obtained.

b (1-e −”)U(S)J-(Se −Ls+a
m)V(S)+bmR(S)+Ke(S)]
(16) Well? = Equations (2), (5), and (7) are also Laplace transform U(S)−b −′ (S+ a
)V(S) (17)bmR(S
)−(S+am)Vm(S) (
18)e (S)-VIII(S)-V(S)
(19) From formulas (16) to (19),
We obtain the following formula (b b −' (S+a) (1−e −
Ls)+S e −”+am+K)V(S)−(S+a
m+K)Vm(S) (20
) Here, Paddy approximation is used in equation (20). That is, substitute the following equation.

e −”−(2−LS)/(2+LS)
(21) Vm(S) 2 b b -' (S+a)LS+5(2-L
S) + (2 + LS) (am + K) Therefore, the conditions under which the above equation is stable (obtained from Table Routh's stability determination).

First, the denominator of equation (22) is rearranged in terms of F(S) and LS.

F(S)-(2b b2'-1)LS2+
(23) [(2a b b −
'+am+K)L+21S+2(am+K)-A@S2
+A+S+A2 Here, from the parameter ranges of equations (3) to (6) and equation (15), it can be seen that AI and A2 are positive, so the following equation becomes a necessary and sufficient condition for stability.

As''(2b bhe'-1)L>O(24) Therefore,
The condition for b is given by the following equation.

b>b/2
(25) From this, b must be taken to be 1/2 or more of the true value (t) Therefore, when the parameter range of equation (4) is taken into consideration, equation (25) becomes the following equation.

b > b max/2
(26) From the above, this estimated value and (1
By using the control human power U obtained from equation 5), (6
) It is possible to obtain a response that satisfies the standard error model of the equation.

Therefore, if the parameter variation b max is known during driving, it is possible to successively obtain the optimal estimated value using equation (26).Here, the variation in running load and the parameter variation in equation (4) are: It can be considered as equivalent. In other words, a large running load is equivalent to a small gain of the controlled object expressed by equation (1). Buried plate: A large running load means that max is small, and conversely, a small running load means that max is large.

Specifically, when considering the road slope as a running load, when going up, the running load is large (bmax is small), and when going down, the running load is small, and bmax is a dog. If bdownmaX is flat and bomax is flat, then the following inequality holds true.

b dcwnmax> b Omax> b upma
Therefore, from equation (26), b max and b dow
If nmax is used, stable constant speed driving control can be achieved in all cases. Since bmax varies due to various factors, it cannot be uniquely determined.
If b is estimated by setting ax to a value that is very large compared to the actual value, stability is always guaranteed. By understanding the range of fluctuation, it is possible to update the estimated value one by one using equation (26) and calculate the optimal control gain.Here, this fluctuation in running load can be found from the actual vehicle speed and throttle opening. As can be seen from equation (1), the value obtained by dividing the amount of change in vehicle speed by the amount of change in throttle opening is considered to be proportional to the running load.

Therefore, the parameter variation corresponding to equation (4) can be calculated by detecting the running load.
). Then, the control human power U that always satisfies the standard error model of equation (6) and that the convergence to the target vehicle speed is always constant regardless of fluctuations in the running load is determined by (15).
It can be given by the formula.

Sui: Both the plant and the reference model are designed with the primary force (
The same thing can be said for the second order, and even for higher orders.
Alternatively, the throttle opening amount may be determined without using a throttle opening sensor by connecting the actuator to a stepping motor and counting the number of driving pulses.
X.

In addition, a road slope detection sensor may be used to detect the traveling load. Effects of the Invention As described above, the present invention provides a reference model that shows a desired response, and adjusts the control gain parameter to 1 according to the traveling load. By updating the number of times, the convergence to the target vehicle speed is always constant regardless of the fluctuations in the running load, resulting in stable and good follow-up performance, and a comfortable ride (i.e., a constant speed with a small amount of change in the throttle valve opening). It has the effect of realizing high-speed running control.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a constant speed cruise control device for a vehicle according to the present invention. FIG. 2 is a control block diagram. FIG. 3 is a diagram of a control law of a time delay controller.

Claims (2)

[Claims] (1) A vehicle speed detection means for detecting the actual vehicle speed, an actuator for adjusting the vehicle speed, a target value setting means for setting the target vehicle speed, and an adaptive control for the actuator so that the output of the vehicle speed detection means becomes the target vehicle speed. One type of time delay control is a control amount calculating means that provides a control input, a running load detecting means that sequentially detects the running load during constant speed running, and a running load detecting means that detects the running load according to the detected value of the running load detecting means. and gain updating means for automatically updating the control gain of the time delay control, and the updated value of the control gain is sequentially calculated based on the fluctuation value of the running load and the time delay control. A constant speed cruise control device for vehicles. (2) The constant speed cruise control device for a vehicle according to claim 1, wherein the traveling load detection is obtained by detecting the actual vehicle speed and the throttle valve opening.