JPS6119456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cruise control device that maintains a constant running speed of an automobile, and particularly to a cruise control device that decelerates the automobile according to the centrifugal force that acts on the automobile when entering a curve during cruise control driving. Regarding.

First, when the cruise control device is set to the desired vehicle speed while driving, the accelerator is activated.
This system automatically controls the vehicle's speed to a constant level without pressing the pedal.When set, the vehicle's speed detected by the vehicle speed sensor is stored, and after that, the stored vehicle speed and the actual vehicle speed are automatically controlled. By comparison, the throttle mechanism is automatically controlled so that if the actual vehicle speed is faster, the throttle valve is slightly closed, and if the actual vehicle speed is slower, the throttle valve is opened.

Conventionally, with this type of cruise control device, once it is set, it always works to maintain a constant vehicle speed regardless of the road condition, so when entering a curve, you may experience the following strange sensations or It has become something that instills a sense of fear in drivers. In other words, on a curved part of the road, a centrifugal force proportional to the square of the entry speed is applied to the car, so it is common sense for an average, experienced driver to enter the curve at a slightly slower speed than when driving in a straight line. However, when driving on cruise control, the vehicle enters the curve at a constant speed. Additionally, when a car enters a curve, the vehicle speed temporarily decreases due to an increase in running resistance, but the cruise control system immediately tries to recover from the yaw caused by centrifugal force, which causes the car to be in an unstable running state. Accelerating, the driving condition of the car becomes increasingly unstable. This tendency becomes more pronounced as the curve becomes steeper.

The present invention has been made in consideration of the above points,
To provide a cruise control device that automatically decelerates a vehicle in response to centrifugal force acting on the vehicle when entering a curve during cruise control driving.

The cruise control device according to the present invention calculates the centrifugal force acting on the vehicle based on the vehicle speed detection signal and the steering angle detection signal, and applies a signal corresponding to the centrifugal force to the main control unit of the cruise control to decelerate the vehicle. This is given as a command.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the basic configuration for explaining the control principle of the cruise control device according to the present invention. It includes a vehicle speed sensor 1 that detects the traveling speed of a vehicle, a sensor that is set when the cruise switch SW is turned on (and reset when it is turned off). ), a sample hold circuit 2 that stores the speed detected by the vehicle speed sensor 1 at that time, and an output c corresponding to the deviation between the output a of this sample hold circuit 2 and the output b of the vehicle speed sensor 1.
A cruise control system consisting of an adder 3 that generates a change in target value, a PID controller 4 that performs optimal response adjustment based on a change in target value, and an output device 5 that adjusts the opening of a throttle valve of a throttle mechanism 6 according to the output of the PID controller 4. A main control unit A, a steering angle sensor 7 that detects the steering angle of the vehicle, a tangent function generator 8 that converts the output d of the steering angle sensor 7 into a tangent function,
a square function generator 9 that squares the output b of the vehicle speed sensor 1; a multiplier 10 that multiplies the output e of the tangent function generator 8 and the output f of the square function generator 9; a full-wave rectifier 11 that rectifies the output of the full-wave rectifier 11;
and an adder 13 that adds a signal g obtained by voltage-adjusting the output of ing.

For something configured like this, first,
When using normal cruise control, the driver turns the cruise switch on when the desired vehicle speed is reached.
When turned on, the sample and hold circuit 2 of the main control section A is set, so that the vehicle speed detected by the vehicle speed sensor 1 at that time is stored in this sample and hold circuit 2. When the cruise switch SW is turned on, the two inputs a and b of the adder 3 are
are equal, the output c is zero, and the output device 5 keeps the valve opening of the throttle mechanism 6 constant so as to maintain the vehicle speed. Thereafter, the actual vehicle speed changes due to changes in road conditions, for example, if it becomes faster than the set speed, b>a, and this causes the negative output c of the adder 3 (c=a
-b) is sent to the output device 5, which drives the throttle mechanism 6 in the direction of deceleration until the actual vehicle speed equals the setpoint. On the contrary, when b<a, the throttle mechanism 6 is driven in the direction of acceleration by the positive output c of the adder 3 corresponding to the difference.

Next, when the car enters a curve while driving on cruise control, the steering angle sensor 7 detects the steering angle θ at that time, and the detection output d is sent to the tangent function generator 8, where a signal corresponding to tanθ is sent. converted to e. At the same time, the vehicle speed detection signal b upon entering the curve is sent to the square function generator 9, where a signal f corresponding to the vehicle speed ^v2 is converted. The outputs e and f of each of these function generators 8 and 9 are multiplied by a multiplier 10, and the output becomes a signal according to v ² · tan θ, which acts on the car according to the curvature (radius r) of the curve. (If the proportional constant of centrifugal force is K, then K ₁・v ² /r=
(obtained by K ₂・v ²・tanθ). The output of the multiplier 10, which is proportional to the centrifugal force applied to the vehicle according to the steering angle θ and the vehicle speed v during this curve traveling, is rectified by the full-wave rectifier 11 (becomes the absolute value of the centrifugal force), and the rectified output is is converted into an appropriate voltage value through the variable resistor 12, and then a deceleration signal g is sent to the main control unit A via the adder 13, and the main control unit A uses the deceleration signal g to control the PID. Throttle mechanism 6 is driven in the deceleration direction via regulator 4 and output device 5.

However, with such a cruise control device, a deceleration command based on the centrifugal force acting on the car depending on the curvature of the curve can be continuously given to the main control section of the cruise control, thereby making it possible to avoid sharp curves. Even when approaching the curve, the vehicle speed will automatically decrease accordingly, allowing the vehicle to safely pass through the curve.

The present invention is directed to such a basic cruise control device, which is capable of performing deceleration control particularly suitable for actual curve driving of an automobile.

FIG. 2 shows an embodiment of the present invention, in which, instead of the full-wave rectifier 11 shown in FIG.
A differentiator 14 consisting of a capacitor and a resistor, and a diode 15 that rectifies the output of this differentiator 14.
and a second sample-and-hold circuit 17 that holds the output of the diode 15 for a set time of a timer 16 consisting of a resistor and a capacitor.

In the cruise control device according to the present invention configured in this way, the output h (signal proportional to centrifugal force) of the multiplier 10 is differentiated by the differentiator 14, and the differentiated output is further rectified by the diode 15. The rectified output i is sent to the sample and hold circuit 17 at the next stage. Since this sample hold circuit 17 discharges at a time determined by the time constant of the timer 16, its output i generates a relatively large voltage when it enters a curve, and then the car makes a steady circular turn following the curvature of the curve. If this is done, the output voltage will become a signal with characteristics such that it gradually attenuates. Therefore, the deceleration signal k corresponding to the output of the sample and hold circuit 17 is sent to the adder 1.
3 to the main control unit A of the cruise control, a relatively large deceleration is performed when the vehicle enters the curve, and thereafter speed control is automatically performed to gradually accelerate and return to a constant speed running state. It can be done. Incidentally, a time chart of the output characteristics of each part at this time is shown in FIG.

Normally, the centrifugal force that acts on a car when it enters a curve is largely due to subsequent steering wheel operations, and even if the car is decelerated greatly when entering the curve and then gradually accelerated, as in this example, the car will not be able to drive around the curve. This can be done stably, and therefore, with the present embodiment, unnecessary deceleration can be suppressed and the curve can be passed efficiently. In this case, in the embodiment shown in FIG. 1, if the curvature of the curve is constant, constant deceleration will be performed until the vehicle exits the curve.

Note that in the above explanation, the centrifugal force acting on the car at the curved portion is indirectly determined by calculation according to the respective detection signals of the vehicle speed v and steering angle θ at that time. However, the present invention is not limited to this in any way; for example, centrifugal force, yaw rate (degree of yaw), etc. may be directly detected using an accelerometer, centrifuge, or gyroscope. Needless to say.

As described above, the cruise control device according to the present invention detects the centrifugal force or yaw rate that acts on the vehicle at a curved portion of the road when driving at a constant speed using the cruise control, and issues a deceleration instruction according to the detection signal as the main control device of the cruise control. This system eliminates the discomfort and fear that drivers experience when entering curves at high speeds, unlike conventional cruise control devices, and provides safety and efficiency even for beginners. It has the excellent advantage of being able to negotiate curves easily and allowing cruise control driving not only on expressways but also on ordinary roads with particularly sharp curves.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a cruise control device according to the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a time chart of signals of various parts in the same embodiment. . A...Main control section, B...Deceleration control section, SW...
Cruise switch, 1... Vehicle speed sensor, 2... Sample hold circuit, 3... Adder, 4... PID
Adjuster, 5... Output device, 6... Throttle mechanism, 7... Rudder angle sensor, 8... Tangent function generator,
9... Square function generator, 10... Multiplier, 11... Full wave rectifier, 14... Differentiator, 16
...Timer, 17...Sample and hold circuit.

Claims (1)

[Claims] 1 The vehicle speed detected by the vehicle speed sensor when the cruise switch is operated is stored in a storage device to set the speed, and the opening degree of the engine throttle valve is adjusted according to the control deviation between the set vehicle speed and the subsequently detected vehicle speed. In those that perform adjustment, the centrifugal force acting on the vehicle body can be calculated by multiplying a signal obtained by squaring the speed detection signal from the vehicle speed sensor and a signal obtained by converting the steering angle detection signal from the steering angle sensor into a tangential signal. There is a means for calculating the magnitude of the centrifugal force, a means for differentiating an output signal proportional to the magnitude of the centrifugal force thus determined, and a means for making the differentiated signal a discharge time constant using a timer consisting of a resistor and a capacitor. 1. A cruise control device comprising: means for sample-holding the sampled and held signal; and means for adding the sample-and-held signal to the control deviation as a deceleration signal.