JPH02259902A - Data holding device for on-vehicle control equipment - Google Patents

Abstract

PURPOSE:To secure correct data even when they are unexpectedly reset by providing a pair of data holding means consisting of a memory to hold the data and a memory to convert and hold the data, and the other data holding means consisting of two types of memories, which convert and hold the latter data. CONSTITUTION:The data in a first memory are firstly rewritten, then the data in a second memory are rewritten to the converted form of the first data. Next the data in a third memory are rewritten to the converted form of a second data, and the data in a fourth memory are rewritten in the converted form of a third data. Before the data are fetched, whether or not the converted data in the first memory corresponds to the data in the second memory is decided, or whether or not the converted data in the third memory corresponds to the data in the fourth memory is decided, when either data corresponds, the corresponding value is taken out. Thus when the data are unexpectedly reset, the correct data can be secured in either one pair of the memories.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a data holding device for a vehicle-mounted control device in which data can be constantly rewritten depending on the driving state.

(Prior art) Vehicles are equipped with various control devices that control the engine and transmission, and many of these control devices are configured with data retention devices so that the data that serves as input information is constantly rewritten according to driving conditions. It has been done. For example, in order to drive a vehicle at a constant speed without operating the accelerator on a highway, etc., a constant speed traveling device for vehicles such as that described in Japanese Patent Application Laid-Open No. 60-255534 is installed. The memory that stores and holds the target vehicle speed for constant speed driving control can be rewritten at any time by a command. In addition, in constant speed driving control, when trying to automatically change the control gain while driving, in order to always perform appropriate control in response to changes in driving resistance and engine deterioration over time. In this case, a memory that can be constantly rewritten is used to store this control gain.

By the way, conventional data holding devices for on-vehicle control equipment are usually configured to store and hold one piece of data in an inverted form in a set of memories, and to retrieve this data as data when two pieces of data match. . In this case, each memory is, for example, 8 bits, and data is first rewritten in the first memory, and then rewritten in the second memory by inverting the bits.

When retrieving data, the data in both memories are compared, and if the data in the second memory is the inverted value of the data in the first memory, this is retrieved as data and the data is inverted. If not, it is assumed that the data is corrupted and the data is initialized.

However, in the case of in-vehicle control equipment, the computer power supply is unstable and suddenly shuts off, or there is an increase in load or disturbance while driving, which can cause a reset signal to be unexpectedly input to the data retention device. If such a reset signal is applied during data rewriting, the data in the two memories will no longer match, and the data will be determined to be corrupted and will be initialized.

Furthermore, in order to avoid data destruction due to such an unexpected input of a reset signal, there is a method of providing a memory hold circuit at the time of reset in the computer, but this would result in a complicated circuit configuration.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and is an in-vehicle control device that is capable of retaining accurate data even in the event of an unexpected reset, without providing a memory hold circuit for reset in the computer. The purpose of this invention is to obtain a data holding device.

(Structure of the Invention) The present invention provides a data holding device for an in-vehicle control device in which data can be rewritten at any time according to the driving state, and includes a first memory for holding data, and a data holding device for storing data held in the first memory. A set of data holding means consisting of a second memory that holds the data in a converted form by bit inversion or the like, a third memory that holds the data held in the second memory in a similarly converted form, and a third memory. This is constituted by another set of data holding means consisting of a fourth memory which holds data held in the same converted form.

(Operation) Data is first rewritten in the first memory,
Then, the data in the second memory is rewritten in the form converted by bit inversion or the like.

Then, the data in the third memory is rewritten in the form in which the data in the second memory is converted, and the fourth memory is further rewritten in the form in which the data in the third memory is converted.

Before extracting data, check whether the value obtained by converting the data in the first memory matches the data in the second memory, or the value obtained by converting the data in the third memory matches the data in the fourth memory. If there is a match in at least one of the sets, the matching value is extracted as data.

(Example) Examples will be described below based on the drawings.

FIG. 1 is an overall system diagram of a constant speed traveling device for a vehicle to which the present invention is applied. This constant speed traveling device for a vehicle includes an actuator 3 that opens and closes a throttle valve l of an engine via an accelerator wire 2, and a control unit 4 that controls the actuator 3. A vehicle speed sensor is installed in the speedometer 5 of the vehicle, and a vehicle speed signal is input to the control unit 4. The control unit 4 also receives command signals for various modes from a command switch (not shown), and also receives brake signals,
Inhibitor signals etc. are manually generated.

Here, the command switch is a resume switch to return to constant speed driving after cancellation.

Coast switch for decelerating while driving at constant speed.

It consists of a main switch as a power switch, a set switch for setting the speed for constant speed driving, and for instructing acceleration during constant speed driving. Further, the actuator 3 is composed of a motor and an electromagnetic clutch.

While driving with normal accelerator operation, the main switch is turned on and the vehicle speed is within a predetermined speed range (for example, 40 to 1100 km/h).
When the set switch is turned on, the vehicle speed at that time is stored in the control unit 4, and at the same time, predictive control is performed and the throttle valve I is driven in the opening direction.

Then, when the vehicle speed reaches the memorized target vehicle speed, the control shifts to PID control.

While driving at a constant speed, the control unit 4 performs a comparison calculation between the actual vehicle speed detected by the vehicle speed sensor and the target vehicle speed, and when the vehicle speed is lower than the target value, the actuator 3
actuator 3 in the forward direction to drive the throttle valve l to the opening side, and when the vehicle speed is high, actuator 3 is operated in the opposite direction to drive the throttle valve 1 to the closing side, and by repeating this, constant speed driving is achieved. maintain.

Additionally, when the set switch is turned on while driving at a constant speed, the throttle valve l is driven to the open side, increasing the vehicle speed, and the vehicle shifts to a constant speed driving state where the target value is the vehicle speed when the set switch was turned off. . Furthermore, when the coast switch is turned on, the throttle valve 1 is driven to the closing side to reduce the vehicle speed, and the vehicle enters a constant speed driving state in which the target value is the vehicle speed when the coast switch is turned off.

Further, when a brake signal or an inhibitor signal is input while the vehicle is traveling at a constant speed, the cancel mode is entered, the electromagnetic clutch in the actuator 3 is turned off, and the accelerator wire 2 is placed in a completely normal accelerator operation state. However, the vehicle speed before cancellation is memorized, and if the resume switch is turned on after the vehicle speed is maintained at approximately 40 km/h or higher by operating the accelerator, the vehicle will be driven at a constant speed again at the vehicle speed set before cancellation. return.

The control unit 4 also counts the sign changes of acceleration, and increases the control gain by a certain value when the number of acceleration sign changes within a certain period of time is less than a predetermined number of times, and increases the control gain by a certain value when the number of acceleration sign changes within a certain time exceeds a predetermined number. Learn by decreasing the value by a certain value.

Figure 2 shows data showing the change characteristics of vehicle speed when moving from a flat road to a steep slope, etc. while driving at a constant speed.
) shows the case of the conventional device, where the control gain has become smaller than the required value due to deterioration of engine performance over time, etc., and (b) shows the case of the above embodiment. In the case of the conventional device, when the vehicle reaches a steep slope, the vehicle speed decreases due to the increase in load, and then gradually returns to the target vehicle speed, but because the gain is small, it takes a long time to return to the target vehicle speed. On the other hand, in the case of the above embodiment, the control gain is gradually adjusted to an appropriate value through learning as shown in FIG. 2(b), so that the target vehicle speed can be quickly returned to.

Next, the above control will be specifically explained with reference to the flowchart shown in FIG. Note that S indicates each step.

Start and first check with Sl to see if the set switch is on. Then, if no, return to the original state, and if yes, go to S2.

In S2, the vehicle speed V is input, and in S3, the vehicle speed V is stored as a target vehicle speed.

Next, in S4, the actual vehicle speed is input. And S
5, and calculate the current vehicle speed deviation Δv n (Δv,=
Difference Δl between V −V−) and previous vehicle speed deviation ΔVn−+
o, then go to S6 and calculate the current vehicle speed deviation Δ
The difference ΔV″0 between Vn and the vehicle speed deviation ΔV n−2 from the time before the previous time is calculated. Then, in S7, Δvo, ΔV′□, ΔV″
7, the operation amount Δθ of the actuator is calculated by the following equation.

Δθ=K T (K pΔv 'n+K IΔvn
"KoΔv"n) where, ni, niko, Ko is a constant, K
T is the overall gain.

Then, the process goes to S8, and the actuator is actuated by the amount of Δθ.

Next, in S9, the differential value ΔVn-1 of the previous vehicle speed deviation and the differential value ΔV' of the current vehicle speed deviation. It is determined in 810 whether there is a sign change between the previous time and this time.

Then, if there is a sign change, Sll
Add 1 to To, which is the count value of the number of times, and S1
2 and subtract 1 from the timer value T.

Further, if the answer is NO in S10, the process directly proceeds to S12.

Next, in S13, it is determined whether the timer value T has become zero. Then, if it is r-0, go to S14,
The count value T0 of S11 is input as the number of sign changes.

Next, in S15, it is determined whether To is larger than the first specified value Kl. Then, if T o > K +, go to S16 and set the gain to 7 to a constant value Δ
Reduce only KT.

If To>Kt, it is checked in S17 whether To is smaller than the second specified value Km (Kt<Kl), and T
O＜K! If so, go to 81B and increase the gain KT by ΔKT.

After that, in S19, the count value T0 is returned to zero, and in S20
The timer value T is returned to the initial value IO, and the process returns to S4.

Also, if S13 is NO, that is, T=0, then S
If the answer to No. 17 is NO, that is, T0=00, the process directly returns to S4.

In the above control, the data holding device in the control unit 4 controls the control gains A, B and C shown in FIG.
, D, and two sets of memories.

Each memory has 8 bits, and B is a bit-inverted version of A, C is a bit-inverted version of B, and D is a bit-inverted version of C. In other words, the data is rewritten as shown by diagonal lines in Figure 4.
First, it is performed on A, and then on B, C, and D in the order of bit inversion of the previous one.

FIG. 5 shows the flow of the data rewriting described above. When starting, first, an inverted value Y of new data X is set. Then, let A be X, then let B be Y, then,
Let C be X, and finally, let D be Y.

By holding data in two sets of memories in this way, even if a reset signal is input during data rewriting, the two memories in one set will remain intact.

When data held in these two sets of memories is retrieved, A and B are first compared, and if B is the inverted value of A, A is used as the data. If not, then C and D are compared, and if D is the inverted value of C, C is extracted as data. If neither value is inverted, it is determined that the data is corrupted, and the data is initialized.

FIG. 6 shows the flow of the above data check.

When starting, first compare A and B. And O
If K, that is, the inverted value of A, and B match, A is taken out as data X.

Furthermore, if B does not match the inverted value of A by N'G, then C and D are compared in the same way. Then, if OK, C is extracted as data X.

If the result is NG, the data is initialized.

In the above embodiment, an 8-bit memory is used and the data in each memory is converted in the form of bit inversion, but various other types of memory can be used. The conversion of the data is not limited to bit inversion, and in short, any form may be used as long as it can be compared before and after conversion.

In addition to maintaining control gains, the present invention can also be applied to record keeping of target vehicle speeds, and can also be applied to various data holding devices for vehicle-mounted control devices other than constant speed traveling devices.

(Effects of the Invention) Since the present invention is configured as described above, it is possible to leave accurate data in any one set of memories even at the time of an unexpected reset, without providing a memory hold circuit at the time of reset in the computer. I can do it.

[Brief explanation of drawings]

FIG. 1 is an overall system diagram of a constant speed traveling device for a vehicle according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing the control characteristics of the constant speed traveling device in comparison with that of a conventional device, and FIG. The figure is a flowchart for executing the basic control of the specific speed traveling device, Figure 4 is an explanatory diagram of data rewriting in the same embodiment, Figure 5 is a flowchart for executing the same data rewriting, and Figure 6 is the data in the same embodiment. 3 is a flowchart for executing a check. 1: Throttle valve, 3: Actuator, 4: Control unit, 5 Speed meter (vehicle speed sensor).

Claims (1)

[Claims] (1) In a data holding device for an in-vehicle control device in which data can be rewritten at any time according to driving conditions, a first memory that holds the data and a converted form of the data held in the first memory are provided. a set of data holding means consisting of a second memory for holding data, a third memory for holding the data held in the second memory in a converted form, and a third memory for holding data held in the second memory;
A fourth method that stores the data stored in memory in a converted form.
1. A data retention device for a vehicle-mounted control device, characterized in that it is provided with another set of data retention means consisting of a memory.