Driving force control apparatus for moving vehicle by desired distance

A driving force control apparatus for moving a vehicle by a desired distance includes an input section for input a desired move distance, a throttle controller section for setting a throttle actuator of the vehicle at an opening degree, an actual moved distance detecting section for detecting an actual moved distance of the vehicle, and a braking section for stopping the vehicle by braking when the vehicle moved the desired distance. Therefore, a slight movement of the vehicle is simplified and therefore the load to a vehicle driver is decreased.

BACKGROUND OF THE INVENTION 
The present invention relates to an apparatus for moving a vehicle by a 
desired distance by controlling a throttle actuator and a braking system 
of the vehicle. 
A variety of methods for automatically driving an automotive vehicle have 
been developed and proposed in order to further improve a reliability of 
vehicles. Japanese Patent Provisional Publication No. 6-2576 discloses an 
electronic throttle control apparatus where a throttle actuator and an 
accelerator pedal are electrically connected for electronically changing 
the relationship between the opening degrees of the throttle and the 
accelerator pedal. That is, by changing the relationship between the 
opening degree of the throttle actuator and the depression degree of the 
accelerator pedal according to the driving condition of the vehicle so 
that a driver can easily drive the vehicle without noticing the change of 
the driving condition. 
However, such a throttle control system is not useful in a case that the 
vehicle is moving in a multi-level parking building so as to get over a 
vehicle stopper while being precisely stopped at a predetermined position. 
That is, percise acceleration-work and timely braking are required by a 
driver during such a vehicle position adjusting operation. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved apparatus 
for automatically moving a vehicle by a desired distance by means of a 
throttle actuator control and a brake control, which apparatus largely 
decreases a driver's load during a slight vehicle-move operation. 
According to an aspect of the present invention, there is provided a 
driving force apparatus for moving a vehicle by a desired distance. The 
vehicle is equipped with a throttle actuator. The driving force apparatus 
comprises an input section, a throttle control section, an actual moved 
distance detecting section, and a braking force generating section. A 
desired move distance is inputted through the input section. The throttle 
control section inputs a throttle opening degree to the throttle actuator. 
The actual moved distance detecting section detects an actual moved 
distance of the vehicle. The braking force generating section stops the 
vehicle when the actual moved distance becomes the desired move distance. 
According to another aspect of the present invention, there is provided a 
driving force control apparatus for moving a vehicle by a desired 
distance. The driving force control apparatus comprises a command 
inputting section, a move distance changing section, a throttle control 
section, an actual moved distance detecting section, and a braking force 
generating section. A driver inputs a move command for moving the vehicle 
through the command inputting section. The move distance changing section 
sets a target move distance when the move command is inputted to the 
command inputting section. The throttle control section inputs a throttle 
opening degree value to a throttle actuator of the vehicle. The actual 
moved distance detecting section detects an actual moved distance of the 
vehicle. The braking force generating section stops the vehicle when the 
actual moved distance becomes the desired move distance. 
According to a further aspect of the present invention, there is provided 
an apparatus for moving an automotive vehicle to a desired distance 
position. The apparatus is installed to the vehicle including an internal 
combustion engine and a braking system. The apparatus comprises a move 
distance command button, a vehicle condition detecting section, a vehicle 
condition detecting section, a throttle actuator, a brake actuator and a 
controller. An operator of the vehicle commands the execution of the 
vehicle moving operation through the move distance command button. The 
vehicle condition detecting section detects a vehicle condition and 
outputs a signal when the vehicle satisfies a predetermined condition. An 
output condition of the internal combustion engine is controlled through a 
throttle actuator of the vehicle. A braking for stopping the vehicle is 
executed through a brake actuator of the brake system. The controller 
starts to control the throttle actuator and the brake actuator while 
monitoring the actual moved distance from the wheel speed sensor when the 
controller receives the signal from the vehicle condition detecting 
section. The controller continues the control of the throttle actuator and 
the brake actuator until the vehicle moves a predetermined distance, and 
then stops the vehicle.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1 and 2, there is shown a first embodiment of a driving 
force control apparatus according to the present invention. 
The driving force control apparatus is for moving an automotive vehicle, 
which is equipped with an internal combustion engine including a throttle 
system and a braking system, by a desired distance. The driving force 
control apparatus comprises a move distance command button 1, a vehicle 
speed sensor 6, an acceleration sensor 8, an acceleration pedal sensor 
pedal 7, a wheel speed sensor 3, a shift position sensor 14, a throttle 
actuator 4, a brake actuator 5, and an alarm 10, each of which is 
connected with a controller 2. The move distance command button 1 
functioning as a move distance inputting means outputs a pulse signal to 
the controller 2 in reply to a pushing of the button 1 by a driver. The 
move distance command button 1 is not a retrigger type, and therefore 
repushing of the button 1 during the moving never increases the move 
distance if the move control has already started. 
The vehicle speed sensor 6 corresponds to a vehicle speed detecting means 
and detects a vehicle speed. The acceleration sensor 8 is installed to a 
vehicle body of the vehicle and detects a fore-and-aft directional 
acceleration applied to the vehicle body. The accelerator pedal sensor 7 
of a mechanical type is connected to an accelerator pedal of the vehicle 
and outputs a pulse signal from a normal open contact or a normal close 
contact. The wheel speed sensor 3 is installed in the vicinity of a wheel 
of the vehicle to detect a wheel rotation speed. The shift position sensor 
14 is installed to an automatic transmission interconnected with the 
internal combustion engine of the vehicle, and detects a selected shift 
position of the automatic transmission. 
The throttle actuator 4 is an electronic control type actuator which 
executes an opening and closing of a throttle valve by means of a driving 
force of an electric motor. The throttle actuator 4 may be an actuator 
which executes the opening and closing of the throttle valve upon 
receiving a command value from the controller 2 even if a driver does not 
push an acceleration pedal. More particularly, a commonly used throttle 
actuator, which is used in a traction controller, is applied to this 
throttle actuator 4. The brake actuator 5 is a pressure-type actuator 
which executes a braking even if a driver does not push the brake pedal. 
More particularly, a commonly used brake actuator, which is used in a 
traction controller, is applied to this brake actuator 5. The alarm 10 is 
a speaker for outputting alarm sound or alarm message and/or a CRT display 
for displaying an alarm message. This alarm 10 is disposed near a driver's 
seat in the vehicle so that the driver can easily recognize such 
information. 
The controller 2 includes a CPU and a ROM, and they may be shared with 
those of an ECU (Engine Control Unit) installed in the vehicle or may be 
separate therefrom. This controller 2 activates a throttle control means, 
a braking force generating means and an actual travel distance detecting 
means by executing software stored in the ROM through the CPU. The 
controller 2 is arranged to execute a control for moving the vehicle by a 
predetermined distance, such as 10 cm, in reply to the input of a pulse 
signal from the move distance command button 1. 
The manner of operation of the first embodiment of the driving force 
control apparatus according to the present invention will be discussed 
hereinafter with reference to a flowchart of FIG. 2. 
At a step S201, the controller 2 decides as to whether the move distance 
command button 1 is pushed or not. When the answer of the step S201 is 
"YES", that is, when the driver pushes the move distance command button 1 
so as to input the pulse signal from the move distance command button 1 to 
the controller 2, the routine proceeds to a step S202. 
At the step S202, the controller 2 decides as to whether the vehicle is 
stopped or not by monitoring the signal from the vehicle speed sensor 6. 
When the answer of the step S202 is "YES", the routine proceeds to a step 
S203 wherein the controller 2 decides as to whether the accelerator pedal 
is not pressured by monitoring the detection signal of the accelerator 
pedal sensor 7. When the answer of the step S203 is "YES", the routine 
proceeds to a step S204 wherein the controller 2 decides according to a 
signal from the shift position sensor 14 as to whether the select lever of 
the automatic transmission is set at a drive range (D position) or not. 
When the answer of the step S204 is "YES", the routine proceeds to a step 
S205 wherein the throttle control means of the controller 2 inputs a 
signal indicative of a throttle opening-degree to the throttle actuator 4, 
and the actual moved distance detecting means of the controller 2 
calculates a rotation angle of the wheel from the rotation pulse obtained 
by the wheel speed sensor 3, that is, the controller 2 calculates an 
actual moved distance. The throttle control means monitors the detection 
value of the actual moved distance detecting means and calculates a 
throttle opening degree value .theta.(t) according to the following 
equation (1). 
EQU .theta.(t)=.alpha.(y(t)-y*)+.beta..DELTA.(y(t)-y*) (1) 
wherein .alpha. and .beta. are constants, y(t) is an actual move-distance 
after time t elapsed, y* is a target move distance, and .DELTA. is a 
difference during time interval .delta.t. 
At a step S206, the braking force generating means of the controller 2 
calculates a brake depression value B(t) by using the following equation 
(2). 
EQU B(t)=.gamma.(exp(-1.multidot.(.epsilon..vertline..vertline.y(t)-y*.vertline 
..vertline.))+.zeta.(exp(-1.multidot.(.DELTA..vertline..vertline.y(t)-y*.ve 
rtline..vertline.)) (2) 
wherein .gamma., .epsilon. and .zeta. are constants, and .DELTA. is a 
difference of time interval .delta.t. 
At a step S207, the controller 2 decides as to whether the actual moved 
distance is smaller than the target move distance or not by comparing the 
detection value of the actual moved distance detecting means with the 
target move distance. When the answer of the step S207 is "YES", the 
routine proceeds to a step S208 wherein the throttle control means of the 
controller 2 decides as to whether the throttle opening degree is greater 
than an upper limit opening-degree value (preset value). When the answer 
of the step S208 is "NO", the routine proceeds to a step S209 wherein the 
controller 2 decides as to whether the vehicle speed is greater than an 
upper limit vehicle speed or not. When the answer of the step S209 is 
"NO", the routine proceeds to a step S210 wherein the controller 2 decides 
as to whether the acceleration detected by the acceleration sensor 8 is 
greater than an upper limit acceleration value or not. When the answer of 
the step S210 is "NO", the routine returns to the step S205 for repeating 
the steps S205 to S210. If the detection value of the actual moved 
distance detecting means is zero at the step S205, the throttle control 
means increases the throttle opening degree value by .delta. at the step 
S206. Such a correction is repeated until the detection value of the 
actual moved distance detecting means takes a positive value. In this 
process, when the opening degree of the accelerator pedal reaches the 
upper limit opening-degree value, that is, when the answer at the step 
S208 becomes "YES", the routine jumps to a step S213 wherein the throttle 
control means outputs a command value for fully closing the acceleration 
throttle to the throttle actuator 4, and the braking force generating 
means promptly stops the vehicle by outputting the pressure command value 
to the brake actuator 5. Similarly, when the answer at any of the steps 
S209 and S210 becomes "YES", the routine jumps to the step S213. 
At a step S214, the controller 2 outputs an alarm signal to the alarm 10 to 
output an alarm sound or an alarm message. This processing is effective in 
case that the running resistance to the vehicle is large, for example, in 
a up-slope or against a step for stopping the vehicle, this function 
prevents the vehicle from being radically accelerated after the up-slope 
or the step. In a case that the vehicle traversed the step before the 
throttle opening degree becomes the upper limit, the vehicle is radically 
accelerated after the step. However, if in such a case the vehicle speed 
becomes greater than the upper limit value or the acceleration of the 
vehicle becomes greater than the upper limit value, the controller 2 
executes the process at the step S213 to stop the vehicle. Further, the 
controller 2 executes the step S213 to stop the vehicle in order to 
prevent the vehicle from moving a distance greater than a predetermined 
distance in a case that the vehicle travels a down-slope or in a case that 
the vehicle speed becomes greater than a predetermined speed due to the 
delay of the braking control or lack of the braking force even if the 
throttle is not opened. Therefore, in a case that the acceleration becomes 
greater than a predetermined value, the controller 2 executes the process 
for stopping the vehicle. 
On the other hand, as the step S207, when the detection value of the actual 
moved distance detecting means becomes the target move distance such as 10 
cm, the brake force generating means outputs the pressure command value to 
the brake actuator 5. The pressure command value is gradually increased 
according to the equation (2). During this operation, both the brake and 
the accelerator may be operated. 
More particularly, when the answer at the step S207 becomes "YES", that is, 
when the detection value of the actual moved distance detecting means 
becomes the target move distance, the routine proceeds to a step S211 
wherein the throttle control means of the controller 2 fully closes the 
throttle by outputting the command for fully closing the throttle to the 
throttle actuator 4, and simultaneously, the braking force generating 
means stops the vehicle by outputting a sufficient pressure command value 
to the brake actuator 5. After the vehicle is stopped, the routine 
proceeds to a step S212 wherein the brake force generating means keeps the 
hill-hold condition of the brake by outputting the pressure command to the 
brake actuator 5. 
On the other hand, when the answer of any of the steps S201 to S204 is 
"NO", the routine jumps to the step S214 wherein the controller 2 outputs 
an alarm signal to the alarm 10 to output alarm sound or an alarm message. 
Although the first embodiment has been shown and described such that the 
move distance command button 1 functions as a move distance inputting 
means, it will be understood that a ten key keyboard may be used as a 
moved distance inputting means such that the driver can freely set the 
move distance. Further, the alarm 10 may be arranged to display the actual 
moved distance of the vehicle during the control in order to inform the 
movement of the vehicle -to the driver. 
With the thus arranged driving force control apparatus, a driver can easily 
executes a delicate vehicle control for slightly moving the vehicle. 
[Second Embodiment] 
Referring to FIGS. 3 and 4, there is shown a second embodiment of the 
driving force control apparatus according to the present invention. The 
second embodiment is generally similar to the first embodiment except that 
a circumference sensor 9 and a corresponding program for utilizing this 
sensor 9 are installed in the apparatus of the second embodiment as shown 
in FIGS. 3 and 4. 
The circumference sensor 9 is constituted by a laser radar or ultrasonic 
sensor and functions as an obstacle detecting means for measuring a 
distance between the vehicle and an obstacle located around the vehicle. 
The logic for realizing a comparing means and a move distance changing 
means is added into the controller 2 in the form of the program. The 
explanation of the same elements as those in the first embodiment is 
omitted herein. 
The manner of operation of the second embodiment of the driving force 
controlling apparatus will be discussed hereinafter with reference to a 
flowchart of FIG. 4. The explanation of the same processing of this 
flowchart as the first embodiment are omitted herein. 
The processing at steps S401 to S404 is the same as that at the steps S201 
to S204 of FIG. 2. When the answer at the step S404 is "YES", the routine 
proceeds to a step S405. 
At the step S405, the controller 2 decides as to whether an obstacle is 
located within a target distance or not (exists around the vehicle and 
more particularly in the proceeding direction of the vehicle or not) on 
the basis of the signal from the circumference sensor 9. When the answer 
of the step S405 is "YES", the routine proceeds to a step S417 wherein the 
target distance is changed into the distance to the obstacle. 
Following this, the routing proceeds to a step S418 wherein the controller 
2 informs that the target move distance was changed by means of the 
display or alarm. This process enables the vehicle to be stopped ahead of 
the detected obstacle with a predetermined distance. Then, the routine 
proceeds to a step S406. When the answer at the step S405 is "NO", the 
routine directly proceeds to the step S406. 
The step S406 and steps S407 and S408 are the same as the steps S205 to 
S207 of FIG. 2. When the answer at the step S408 is "YES", the routine 
proceeds to the step S413. The step S413 and a step S414 are the same as 
the steps S211 and S212 of FIG. 2. When the answer at the step S408 is 
"NO, the routine proceeds to a step S409. 
At the step S409, the controller 2 again decides as to whether the obstacle 
is located within the target distance or not. When the answer at the step 
S409 is "NO", the routine proceeds to the step S410. The step S410 and 
steps S411 and S412 are the same as the steps S208 to S210. When the 
answer at the step S409 is "YES", the routine proceeds to a step S415. The 
step S415 and a step 416 are the same as the steps S213 and S214 of FIG. 
2. 
It will be understood that the second embodiment of the driving force 
control apparatus according to the present invention may be arranged to 
inform the change of the target move distance through the alarm 10 in a 
case that the target move distance is changed. 
With this arrangement, in a case that the vehicle is controlled in a narrow 
space such as a parking area, the moving control is executed while the 
detection of an obstacle is executed. This enables the vehicle to be 
securely moved without colliding with the obstacle. 
[Third Embodiment] 
Referring to FIGS. 5 and 6, there is shown a third embodiment of the 
driving force control apparatus according to the present invention. The 
third embodiment is generally similar to the first embodiment except that 
a wiper switch 11, an ambient temperature sensor 12 and corresponding 
program for utilizing these elements 11 and 12 are installed in the 
apparatus of the third embodiment as shown in FIGS. 5 and 6. The 
explanation of the same elements as those in the first embodiment is 
omitted herein. 
The wiper switch 11 for operating a wiper (not shown) of the vehicle is 
arranged to output a signal according the turning-on thereof. The ambient 
temperature sensor 12 for detecting the temperature outside of the vehicle 
is installed to the vehicle and outputs a signal indicative of the ambient 
temperature to the controller 2. The logic for realizing a friction 
coefficient detecting means is added into the controller 2 in the form of 
the program. 
The manner of operation of the third embodiment of the driving force 
control apparatus will be discussed hereinafter with reference to a 
flowchart of FIG. 6. The explanation of the same processes as those of the 
first embodiment are omitted herein. 
At a step S601, the controller 2 decides as to whether the wiper switch 11 
is turned on or not after the move distance command button 1 is pushed. 
When the answer at the step S601 is "YES", the routine proceeds to a step 
S604 wherein the controller 2 outputs a massage indicative of the 
impossibility of the operation through the alarm 10. That is, if a road 
surface is wet due to rain which is detected by the signal from the wiper 
switch, the wheels of the vehicle may be excessively rotated. Therefore, 
since in such a condition it is difficult to precisely detect the 
moving-distance of the vehicle, the apparatus is arranged so as not to 
execute the present control. When the answer at the step S601 is "YES", 
the routine proceeds to a step S602 wherein the controller 2 decides as to 
whether the ambient temperature is smaller than or equal to a lower limit 
temperature or not by comparing the detection value of the ambient 
temperature sensor 12 with the lower limit value. That is, if a road 
surface is covered with snow or ice due to the cold weather condition, the 
wheels of the vehicle may be excessively rotated and the braking can not 
be effectively operated. Therefore, the apparatus is arranged so as not to 
execute the present control in such cold condition, such as when the 
ambient temperature is lower than -5.degree. C. When the answer at the 
step S602 is "NO", that is, when the ambient temperature is higher than 
the lower limit temperature such as -5.degree. C., the routine proceeds to 
a step S603 wherein the control of the flowchart of FIG. 2 is executed. 
With the thus-arranged embodiment, the control for the preset distance 
movement is not executed in the condition that the precise movement cannot 
be executed due to the weather condition. Therefore, a reliability of this 
control is further improved. 
[Fourth Embodiment] 
Referring to FIGS. 7 and 8, there is shown a fourth embodiment of the 
driving force control apparatus according to the present invention. 
The fourth embodiment is generally similar to the first embodiment except 
that a brake pedal sensor 13 and its corresponding program for utilizing 
this element 13 are installed in the apparatus of the fourth embodiment as 
shown in FIGS. 7 and 8. The explanation of the same elements as those in 
the first embodiment is omitted herein. 
The brake pedal sensor 13 is a sensor for detecting the depression degree 
of a brake pedal (not shown) and outputting a signal indicative of the 
depression degree to the controller 2, and its structure is basically 
similar to that of the accelerator. The program of the fourth embodiment 
includes a logic for stopping the control by stopping the vehicle when the 
depression of the brake pedal is detected during the preset-distance 
movement operation. 
The manner of operation of the second embodiment of the drive-force 
controlling means will be discussed hereinafter with reference to a 
flowchart of FIG. 8. The explanation of the same processes as those of the 
first embodiment are omitted herein. 
Steps S801 to S810 are the same as the steps S201 to S210 of FIG. 2. 
Following to the "YES" answer of the step S810, at a step S811, the 
controller 2 decides as to whether the brake pedal is depressed by the 
driver or not. When the answer at the step S810 is "YES", the routine 
proceeds to the step S814 wherein the throttle control means outputs a 
command value for fully closing the acceleration throttle to the throttle 
actuator 4, and the braking force generating means promptly stops the 
vehicle by outputting the pressure command value to the brake actuator 5. 
The step S814 and a step S815 corresponds to the steps S213 and S214 of 
FIG. 2. When the answer at the step S811 is "NO", the routine returns to 
the step S807 to repeat the steps S807 to S811. Steps S812 and S813 
corresponds to the step S211 and S212 of FIG. 2. 
With the fourth embodiment of the driving force control apparatus according 
to the present invention, even during this moving operation, the driver 
can freely and safely stop the vehicle. 
Although the preferred embodiments have been shown and described to start 
the driving force control for moving the vehicle by a desired distance by 
pushing the move distance command button 1, it will be understood that 
such a commanding means may be arranged to be installed in the select 
lever of the automatic transmission as shown in FIGS. 9A and 9B. That is, 
a special position such as a constant move position is provided in the 
select lever position, and when the select lever is set in the constant 
move position, the move distance command for starting the operation 
according to present invention is started by the depression of the 
accelerator pedal. Further, this type commanding means shown in FIGS. 9A 
and 9B may be arranged such that several times operations of this special 
shifting extends a predetermined move distance to the several times 
thereof. 
Although the invention has been described in its preferred forms with a 
certain degree of particularity, it is understood that the present 
disclosures of the preferred forms may be changed in the details of 
construction and the combination and arrangement of parts may be resorted 
to without departing from the sprit and the scope of the invention as 
hereinafter claimed.