JPH0210735B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant speed running system for a vehicle, and more particularly to a constant speed running system for a vehicle that determines an optimum control gain depending on the slope of the road surface and causes the vehicle to run at a set speed.

Conventionally, in constant-speed vehicle running systems that automatically maintain a constant running speed of a vehicle, the optimum control gain has been set relatively low to prevent hunting, especially when running downhill.

However, when the optimal control gain is set low in this manner, the current vehicle speed deviates relatively greatly from the set vehicle speed, especially when traveling uphill, making it difficult to maintain the desired constant speed.

The present invention aims to solve the above points,
The purpose is to determine the optimal control gain depending on the slope of the road surface, and to maintain good constant speed driving, especially on uphill slopes. Therefore, the constant speed traveling device for a vehicle according to the present invention includes a slope sensor that detects the slope of the road surface on which the vehicle is running and outputs slope information corresponding to the slope, and a slope sensor that detects the slope of the road surface on which the vehicle is running and outputs slope information corresponding to the slope, and When , reduce the control gain,
A calculation means that increases the control gain when traveling uphill to determine an optimum control gain, and calculates the value of the control signal to be supplied to the throttle actuator based on the optimum control gain, traveling speed information from the vehicle speed sensor, and set speed information. The present invention is characterized in that the throttle opening degree is adjusted based on the calculation result by the calculation means to cause the vehicle to travel at a set speed. The present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of a constant speed traveling device for a vehicle according to the present invention, FIGS. 2 and 3 are flowcharts for explaining its processing operation, and FIG. The electrical circuit diagrams of FIGS. 5 and 6 each show a schematic diagram of the slope sensor.

In FIG. 1, reference numeral 1 denotes a microcomputer which is an example of the calculating means according to the present invention, and the computer 1 outputs instruction signals a and b from the set switch 2 and cancel switch 3, traveling speed information c from the vehicle speed sensor 4, and slope sensor 5. The control valve control signal e and the control valve control signal f corresponding to the slope information d are outputted to the throttle actuator 6 based on the slope information d. Here, the control valve control signal e is for controlling the operation of a control valve (not shown) built into the actuator 6, while the release valve control signal f is for controlling the release valve (not shown). This is to control the operation of the 2 is a set switch, which is mainly operated when specifying constant speed driving;
3 is a cancel switch which is switched in response to brake pedal operation, etc. 4 is a reed switch type or photocoupler type vehicle speed sensor which outputs traveling speed information c corresponding to the traveling speed of the vehicle; 5 is a device that outputs traveling speed information c corresponding to the traveling speed of the vehicle. A sensor that outputs slope information d corresponding to the slope of the road surface, 6
is a throttle actuator (hereinafter simply referred to as actuator), which opens and closes the control valve and release valve based on the control valve control signal e and release valve control signal f from the microcomputer 1, and the throttle actuator opens and closes in response to changes in negative pressure in the diaphragm chamber. 7 represents a throttle valve, which controls the opening and closing of the throttle valve 7. An example of the processing operation will be described below with reference to the flowcharts of FIGS. 2 and 3.

When the main switch (not shown) is turned on while the vehicle is running, a constant voltage is applied from the battery (not shown) to the microcomputer 1, and the microcomputer 1 is put into a reset state, for example as will be described later. The set flag is reset to "0".

The microcomputer is equipped with a storage section and an arithmetic processing section, and after being initialized in step 101 as described above, the following processing is sequentially executed in the arithmetic processing section.

First, a vehicle speed calculation step 102 is executed to calculate corresponding vehicle speed data based on the traveling speed information c from the vehicle speed sensor 4.

Next, cancel ON determination step 103 is executed. At this point, the cancellation instruction signal from the cancel switch 3, that is, the instruction signal due to the brake operation, the instruction signal due to the parking brake operation, and the instruction signal due to the neutral operation, is not input, so the determination result is "NO", and then the set ON is applied. A decision step 104 is executed.

In the set ON determination step 104, the determination result is "NO" since the set switch 2 has not been turned on, and then the set flag=0 determination step 105 is executed.

In the set flag=0 determination step 105, since the set flag has been set to "0" by the initialization as described above, the determination result is "YES", and then the cancel processing step is performed.
106 is executed.

In the cancel processing step 106, processing is performed to set the intermittent ratio, that is, the duty, of the control valve control signal e for operating the control valve of the actuator 6 to a value that can be kept within the non-operating range of the actuator 6, and to set the release valve to the off state, that is, the duty. In order to open the valve, a process is performed in which the release valve control signal f is set to a low level value.

Next, execute the vehicle speed calculation step 102 again, and proceed to the vehicle speed calculation step 102 and the cancel ON judgment step.
103, set ON determination step 104, set flag=0 determination step 105, and cancel processing step
A closed loop consisting of 106 is repeatedly executed.

When the driver turns on the set switch 3 in order to drive at a constant speed during this closed loop execution, the determination result in the set ON determination step 104 is reversed to "YES", so the set flag=1 determination step 107 is performed. is executed.

In the set flag=1 determination step 107, since the set flag is still set to "0", the determination result is "NO", and then the set flag=1 step 108 is executed.

In the set flag=1 step 108, processing is performed to rewrite the set flag from "0" to "1".

Next, a coast step 109 is executed to invert the release valve control signal f to a high level value to switch the release valve to the on or closed state.

Next, a vehicle speed calculation step 102 is executed, followed by a cancel ON determination step 103, a set ON determination step 104, and a set flag=1 determination step 107.
are executed sequentially.

In the set flag=1 determination step 107, since the set flag has been rewritten to "1" as described above, the determination result is reversed to "YES", and then the coast step 109 is executed.

Next, execute vehicle speed calculation step 102, perform vehicle speed calculation step 102, cancel ON judgment step 103, set ON judgment step 104, and set flag = 1.
A closed loop consisting of determination step 107 and coast step 109 is repeatedly executed until the set switch 2 returns to the OFF state.

When the set switch 2 is turned off, the determination result in the set ON determination step 104 becomes "NO" again, and then the set flag=0 determination step 105 is executed.

In the set flag=0 determination step 105,
Since the set flag is set to "1", the judgment result is "NO", and then the set flag is set to 2.
A decision step 110 is executed.

In the set flag=2 determination step 110,
Similarly, the determination result becomes "NO", and then the set flag=2 step 111 is executed.

In the set flag=2 step 111, the set flag is rewritten from "1" to "2".

Next, the vehicle speed storage step 112 is executed, and the vehicle speed calculation step 102 immediately before the set switch 2 returns to OFF is executed.
The vehicle speed data calculated in is written into the storage section as set vehicle speed data.

Next, a set duty calculation step 113 is executed to calculate the set duty. Here, the set duty is D _s in the following equation D = D _s + G [V _s + (V _t + V _t - V _t-1 /△tk)] which determines the intermittent ratio of the control valve control signal e, that is, the duty D. Calculated based on vehicle speed data.

Next, a slope acquisition step 114 is executed, and slope information d from the slope sensor 5 is acquired. As shown in FIG. 5, when the vehicle is running on a flat road, the slope sensor 5 moves the pendulum 301 to the
02 and the spring 302 in opposite directions to maintain the balance as shown in the figure, and when the vehicle is traveling downhill, the pendulum 301 pulls the springs 302 and
The switch _S1 is closed by overcoming the drag force of the pendulum 301, and when the vehicle is traveling uphill, the pendulum 301 operates so that the other switch _S2 is closed.

Next, gain calculation step 115 is executed.

This step 115 performs processing as specifically illustrated in FIG. In FIG. 3, 201 represents a step for determining whether or not the downlink detection switch _S1 is turned on.

202 represents a step in which the contents of the counter M are incremented by "+1".

203 represents a step for determining whether the contents of the counter M exceed the reference value T or not.

204 represents a step for setting the control gain G, that is, G in the above-described duty calculation formula used when executing the next step, autodrive control step 116, to a predetermined low value.

205 represents a step of determining whether or not the upstream detection switch _S2 is turned on.

206 represents a step in which the contents of the counter N are incremented by "+1".

207 represents a step of determining whether the contents of the counter N exceed the reference value T or not.

208 represents a step of setting the control gain G to a predetermined high value.

209 represents a step for resetting the contents of counters M and N to "0".

210 represents a step of setting the control gain G to a predetermined intermediate value.

In this gain calculation step, when the car is running on a flat road, normally both the switch _S1 and the switch _S2 of the slope sensor 5 are turned off, so the judgment result in step 201 is "NO". The determination result in step 205 is "NO", and step 210 is executed via step 209, and the control gain G is set to an intermediate value, that is, G. On the other hand, while driving on this flat road, the vehicle body moves due to road surface conditions, etc., causing switch _S1 and/or switch
If S ₂ repeatedly turns on and off, step
202 or step 206 is executed and the switch _S1 on period or switch _S2 on period is counted by counter M or counter N, but step
Since the reference value T of steps 203 and 207 is set in advance to a relatively large value so that steps 204 or 208 will not be executed due to such fluctuations, the value of counter M or counter N will never exceed the reference value T. Therefore, the determination result in step 203 or step 207 is "NO", and accordingly, an intermediate value, ie, mid-G, is selected as the control gain G, as in the case of normal flat road driving described above. Based on the control gain G in this intermediate value G, the duty D in the subsequent auto drive control step 116 is calculated.

Furthermore, when the car starts traveling downhill with a slope greater than a predetermined slope and the switch S1 of the slope sensor 5 is turned on, before a predetermined period of time, that is, a period corresponding to the reference value T, has elapsed from the point of turning on the switch _S1 . Step 210 is executed in the same way as in the case of flat road driving described above, and the control gain G is set to the intermediate value G. However, if the switch _S1 is still turned on and this on period exceeds the predetermined period, Step 204 is newly executed and the control gain G is changed from the intermediate value G medium to the low value G small. Then, in the subsequent autodrive control step 116, the duty D is calculated based on the control gain G of the low value G.

Furthermore, when the vehicle changes from traveling on a flat road to traveling uphill with a predetermined inclination or higher and the switch _S2 of the slope sensor 5 is turned on, a predetermined period from the time when the switch S2 is turned on, that is, a period corresponding to the reference value T. Before the time elapses, step 210 is executed in the same way as in the case of flat road driving described above, and the control gain G is set to the intermediate value G.
However, if the switch _S2 continues to be turned on and the on period exceeds the predetermined period, step 208 is newly executed and the control gain G is changed from the intermediate value G to the high value G large. . and subsequent autodrive control steps
At step 116, the duty D is calculated based on the control gain G having the high value G.

Next, autodrive control step 116 in FIG. 2 is executed. That is, the vehicle speed data calculated in the vehicle speed calculation step 102 immediately before the set switch 2 returns to OFF (corresponding to V _t in the above formula) and the previous vehicle speed calculation step a predetermined number of times N ago are used.
The previous vehicle speed data calculated in step 102 (corresponding to V _t-1 in the above formula), the time between the two vehicle speed calculation steps 102 (corresponding to Δt in the above formula), and the time stored in step 112 The set vehicle speed data written in the section, that is, the set speed information (corresponding to V _s in the above formula) and the step
Based on the set duty D _s calculated in step 113 and the optimum control gain G calculated in step 115, the above equation is calculated to calculate the duty D. The control valve control signal e with the calculated duty D is then supplied to the control valve, the negative pressure in the diaphragm chamber is regulated, the opening degree of the throttle valve 7 is adjusted, and the vehicle runs at the set speed. be made into

That is, when driving on a flat road, the duty D is calculated based on the control gain G in the intermediate value G, so the duty value is at an intermediate level, and the opening degree of the throttle valve 7 is changed via the actuator 6 accordingly. becomes an intermediate value, and the car runs at the set speed. In addition, in the downhill running state, the duty D is calculated based on the control gain G with the low value G small, so the duty value is at a low level.
In response to this, the opening degree of the throttle valve 7 is reduced to a low value via the actuator 6, and the traveling speed can similarly be maintained at the set vehicle speed. Furthermore, in an uphill running state, the duty D is calculated based on the control gain G with a large high value G, so the duty value becomes a high level duty value, and the opening degree of the throttle valve 7 is changed via the actuator 6 accordingly. high price,
Similarly, the traveling speed can be maintained at the set vehicle speed.

Next, a vehicle speed calculation step 102 is executed, followed by a cancel ON determination step 103, a set ON determination step 104, a set flag=0 determination step 105, and a set flag=2 determination step 110.

In the set flag=2 determination step 110, since the set flag was set to "2" in step 111, the determination result is reversed to "YES", and then the slope signal acquisition step 114 is executed.

Next, a gain calculation step 115 is executed to calculate the optimal control gain G as described above based on the slope information d.

Next, auto drive control step 116 is executed. This autodrive control step 116 is similar to the process described above. However, in this auto drive control step 116, the parameters D _s , V s , and Δt are the same among the parameters D _s , G, V _s , _and Δt for duty D calculation in the previous auto drive control step 116. are used, but other parameters G, V _t ,
For V _t-1 , the latest optimal control gain G calculated in step 115 above, and step 102 above, respectively.
The latest vehicle speed data V _t calculated in step 102, and the vehicle speed data V _t-1 calculated in vehicle speed calculation step 102 a predetermined number of times N before the vehicle speed calculation in step 102 above.
is used. The control valve control signal e having the calculated duty D is then supplied to the control valve, and the opening degree of the throttle valve 7 is adjusted in accordance with the duty D.

Next, vehicle speed calculation step 102 is executed.

Then, from this vehicle speed calculation step 102, the cancel ON determination step 103 and the set ON determination step are performed.
104, set flag = 0 determination step 105, set flag = 2 determination step 110, slope signal acquisition step 114, gain calculation step 115, and auto drive control step 116, and the closed loop leading to vehicle speed calculation step 102 is repeatedly executed until a cancel operation is performed. Each time the closed loop is executed, the opening degree of the throttle valve 7 is adjusted in accordance with the duty D based on the optimum control gain G calculated in the gain calculation step 115.

In this manner, during autodrive driving, the optimal control gain G is calculated according to the slope of the road surface, the duty D is calculated based on this gain G, and the opening degree of the throttle valve 7 is adjusted.

Then, when a brake operation, neutral operation, parking brake operation, etc. is performed and a cancel signal is input, the determination result in the cancel ON determination step 103 during the closed loop is reversed to "YES", and the closed loop is canceled. Then, cancel processing step 106 is executed.

In the cancel processing step 106, a duty setting process for inactivating the actuator 6 and a process for turning off the release valve are performed, and a process for setting the set flag to "0" is also performed.

Next, vehicle speed calculation step 102 is executed, and from vehicle speed calculation step 102, cancel ON judgment step is executed.
103 and cancel processing step 106 to vehicle speed calculation step 102, which is executed until the cancel signal b is inverted to a low level value.

When the cancel operation is released, the judgment result in the cancel ON judgment step 103 is reversed to "NO", and the vehicle speed calculation step is started.
Cancel ON judgment step 103 from 102, set
A closed loop is formed through ON determination step 104, set flag=0 determination step 105, and cancel processing step 106 to vehicle speed calculation step 102, and this closed loop is executed until the set switch 2 is turned on.

In this way, in this embodiment, the optimum control gain G is determined according to the slope of the road surface, and the duty D is determined. Therefore, the optimum duty D corresponding to the slope of the road surface can be obtained, and stable running on uphill and downhill slopes can be maintained.

FIG. 4 shows another embodiment of the present invention, in which the calculation means is constructed from an analog electric circuit.

In Fig. 4, 8 is a battery power supply mounted on the vehicle; 9
10 is a main switch, 10 is a power supply transistor that switches and controls the power supply to a control valve drive solenoid 11 in the actuator 6, 11 is a control valve drive solenoid, and 12 is a frequency/voltage conversion circuit that changes the speed of the vehicle. 13 is a vehicle speed change component extraction circuit which outputs a voltage having a level value proportional to the switching frequency of the corresponding vehicle speed sensor 4, and outputs the voltage between the terminals of the storage capacitor 14 at the time when the set switch 2 is closed and then opened. is a set voltage, and outputs a voltage corresponding to this reference voltage and the output voltage fluctuation of the frequency/voltage conversion circuit 12 corresponding to changes in vehicle speed. 15 is a filter circuit that prevents response delays of the actuator 6, etc. 16 is a modulation circuit that outputs a pulse signal with an intermittent ratio corresponding to the output voltage from the filter circuit 15; 17 is a power amplification circuit and a modulation circuit 1
6 amplify the pulse signal and supply it to the control valve drive solenoid 11, respectively.

When the main switch 9 is closed, a closed circuit consisting of the vehicle-mounted battery 8, the resistor 19, and the constant voltage diode 20 is formed, and the frequency/voltage conversion circuit 12, the vehicle speed change component extraction circuit 13, and the filter circuit are formed. 15 and the modulation circuit 16 with a constant voltage diode 2
A constant voltage of 0 is now commonly applied.

In the frequency/voltage conversion circuit 12, a vehicle speed sensor 4 that switches at a frequency proportional to the vehicle speed is used.
Transistor 21 synchronizes with the switching operation of
performs a switching operation, and a voltage proportional to the switching frequency of this transistor 21 is applied to an integrating circuit 2 including an operational amplifier 22 and a feedback capacitor 23.
Output from 4. That is, frequency/voltage conversion circuit 1
The output voltage of No. 2 is made to have a level value proportional to the vehicle speed.

In the vehicle speed change component extraction circuit 13, when the set switch 2 is turned on or closed and then automatically reset and turned off or opened, the frequency/voltage conversion circuit 1 at that time is connected between the terminals of the storage capacitor 14.
The difference voltage (V _{W −V W} ) between the output voltage of the battery 25 (V W in the figure) and the reference voltage (V _M in the figure ₎ of the battery ₂₅ is stored as the set voltage, that is, the set speed information. At the set switch 2 side terminal of the storage capacitor 14, a voltage is generated which is increased or decreased from the reference voltage V _M by a voltage variation ΔV _W corresponding to the change in vehicle speed. Therefore, the source load resistance 27 of the field effect transistor 26
There is a variable output voltage (V _s shown in the figure) that has a value approximately equal to the reference voltage V immediately after the set switch 2 is opened, and thereafter has a value approximately equal to the sum of the vehicle speed change component ΔV _W and the reference voltage _VM . ) occurs.

The filter circuit 15 includes a voltage follower type operational amplifier 28, a phase lead/lag circuit 33 consisting of a series connection circuit of a resistor 29 and a capacitor 30, and a parallel connection circuit of a resistor 31 and a capacitor 32, and the output voltage with respect to the input voltage _Vs. The response of V _d is set to have predetermined bandpass filter characteristics. In this bandpass filter characteristic, the pass gain gradually increases from a frequency (approximately 0.1 Hz) that is approximately the same as the gain attenuation frequency in the response characteristics of the actuator 6 to a gain attenuation frequency (approximately 1 Hz) of the frequency/voltage conversion circuit 12. It is also set to reduce the pass gain in a high frequency region to prevent the downstream circuit from malfunctioning due to electrical noise.

The modulation circuit 16 is a triangular wave oscillation circuit 34 that generates a triangular wave signal voltage with a constant frequency, for example, about 30 [Hz].
, the slope sensor 5 that controls the amplitude of the triangular wave oscillation circuit 34, and the output voltage V _d from the filter circuit 15.
The comparator circuit 35 detects when V d crosses the triangular wave signal voltage from the triangular wave oscillation circuit 34 and outputs a pulse train signal with an interruption ratio corresponding to the magnitude of the output voltage V _d . The intermittent ratio of this pulse train signal corresponds to the magnitude of the output voltage V _d and also corresponds to the amplitude of the triangular wave oscillation circuit 34 determined based on the slope information from the slope sensor 5. here,
In the slope sensor 5, the switches 36, 37, and 38 are closed while driving uphill, on a flat road, and downhill, respectively, and each switch 36, switch 37, and switch 38 have a pair of switches. The resistance value of the resistor 40, resistor 41, and resistor 42 corresponding to resistor 40>
It is set in advance so that resistance 41>resistance 42. The amplitude of the triangular wave oscillation circuit 34 is set to a low value while traveling uphill, an intermediate value while traveling on a flat road, and a high value while traveling downhill. In other words, the optimal control gain G is set to a high value while traveling uphill, an intermediate value while traveling on a flat road, and a low value while traveling downhill.

In the power amplifier circuit 17, the power supply transistor 10 performs a switching operation in synchronization with the output pulse train signal from the modulation circuit 16, and power from the vehicle-mounted battery 8 is intermittently supplied to the control valve drive solenoid 11.

Other symbols 44 and 45 in the figure are operational amplifiers, 46 and 47 are diodes, respectively.
48 to 51 are capacitors, 52 to 6, respectively.
7 is a resistor, 68 is a reference voltage source, and 69 is a switch that operates in conjunction with the set switch 2.

Since the amplitude of the triangular wave oscillation circuit 34 is selected in accordance with the slope of the road surface and the optimum control gain is determined, the control valve control signal with the optimum duty is applied to the control valve drive solenoid 1.
1. Therefore, the opening degree of the throttle valve 7 can be adjusted optimally, and it is possible to achieve sufficiently stable running and to expect an improvement in fuel efficiency.

FIG. 6 shows a slope sensor 5 used in the embodiment shown in FIG.
FIG. 3 is a diagram schematically showing another example. When the vehicle is running on a flat road, the sensor 5 is held in the state shown in the figure by the magnetic attraction force of the magnet 304 placed below the pendulum 301, and is connected between terminals A and B. A parallel resistor consisting of two resistors, a resistor 305 and a resistor 306, is interposed, and when the vehicle is traveling downhill, the pendulum 301 overcomes the magnetic attraction force of the magnet 304 and moves to the left in the drawing, Resistor 305 and resistor 306 between terminals A and B
and resistor 307, and when the vehicle is traveling uphill,
The structure is such that the pendulum 301 moves to the right in the drawing, and only the resistor 305 is interposed between terminals A and B. Even when this slope sensor 5 is used, the same operation as described above is performed, and the throttle valve 7 is optimally controlled according to the slope of the road surface.

As explained above, the present invention includes a slope sensor that detects the slope of the road surface on which the vehicle is running and outputs slope information corresponding to the slope, and controls when the vehicle is traveling downhill according to the slope detected by the slope sensor. Determine the optimum control gain by setting a small gain and increasing the control gain when going uphill, and calculate the value of the control signal to be supplied to the throttle actuator based on the optimum control gain, the traveling speed information from the vehicle speed sensor, and the set speed information. The throttle opening is adjusted based on the calculation result of the calculation means to cause the vehicle to travel at a set speed.

For this reason, the duty is determined in accordance with the optimum control gain according to the slope of the road surface, and the opening of the throttle valve is adjusted optimally, making it possible to maintain constant speed driving on uphill and downhill slopes, while reducing fuel consumption. can be expected to improve.

In the above-described embodiment, a pendulum type sensor is used as the slope sensor 5, but it is free to use a sensor having a damping effect that prevents excessive response to vibrations of the vehicle body.

Further, in the above embodiment, a setting type sensor for detecting uphill, downhill, and flat roads is used as the slope sensor 5, and the control gain is set in three stages, but the present invention is not limited to this. First, we also use a sensor that detects the slope of the road in an analog way.
In addition, the control gain may be configured to be set in multiple stages or continuously in the calculation means 1 accordingly.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an embodiment of a constant speed traveling device for a vehicle according to the present invention, FIGS. 2 and 3 are flowcharts for explaining its processing operation, and FIG. The electrical circuit diagrams of FIGS. 5 and 6 each show a schematic diagram of the slope sensor. 1... Calculation means, 4... Vehicle speed sensor, 5... Slope sensor, 6... Throttle actuator,
7... Throttle valve.

Claims (1)

[Claims] 1. A slope sensor that detects the slope of the road surface the vehicle is traveling on and outputs slope information corresponding to the slope; In this case, the control gain is increased to determine an optimum control gain, and a calculation means is provided for calculating the value of the control signal to be supplied to the throttle actuator based on the optimum control gain, the traveling speed information from the vehicle speed sensor, and the set speed information. A constant speed traveling device for a vehicle, characterized in that the throttle opening degree is adjusted based on the calculation result by the calculation means to cause the vehicle to travel at a set speed.