Vehicular run controlling apparatus and method for automotive vehicle

In a vehicular run controlling apparatus and method, a vehicular run controller is provided to perform a vehicular run control on the basis of a vehicular velocity of the vehicle and a vehicular running environment surrounding the vehicle, the vehicular run controller having at least two control modes of a control wait mode and a vehicular run mode, falling in a state of the vehicular run control when a start of the vehicular run control by means of the vehicular run controller is set through a vehicular run control setter, falling in a halt state of the vehicular run control when a release of the vehicular run control is set through the vehicular run control setter, carrying out a mode transition from one control mode to the other control mode when the mode transition from the one control mode to the other control mode is instructed through a mode transition instructor according to a vehicular driver's will and when a predetermined condition is established during the vehicular run control irrespective of the vehicular driver's will, and informing the vehicular driver through an informing device such as an alarm unit of an occurrence of the mode transition from the one control mode to the other control mode when the mode transition from the one control mode to the other control mode occurs.

BACKGROUND OF THE INVENTION
 1. Field of the invention
 The present invention relates to vehicular run controlling apparatus and
 method for an automotive vehicle which detect a vehicular running
 environment surrounding the vehicle, for example, detect a preceding
 vehicle which is running ahead of the vehicle or a white line on a road
 surface on which the vehicle is running to perform a vehicular run
 control.
 2. Description of the related art
 A Japanese Patent Application First Publication No. Heisei 7-47862
 published on Feb. 21, 1995 exemplifies a previously proposed vehicular run
 controlling apparatus.
 In the previously proposed vehicular run controlling apparatus, when a
 vehicular driver pushes a set switch during a vehicular run, even with an
 accelerator pedal released, the vehicle falls in a, so-called, following
 control state such that the vehicle is running, maintaining an appropriate
 inter-vehicle distance from the vehicle to such a preceding vehicle as
 described above if the preceding is present, and the vehicle is cruising
 maintaining a previously set vehicular velocity if no preceding vehicle is
 present.
 In addition, this following control state is released when the vehicular
 driver manipulates a brake pedal or the accelerator pedal or changes a
 present gear range position to another range of a vehicular automatic
 transmission.
 Furthermore, when the vehicular velocity of the vehicle falls out of a
 predetermined controllable range of the vehicular velocity within which
 the vehicular velocity can be controlled during the following control
 described above, the following control is automatically released without
 intervention of the vehicular driver's manipulation for the vehicle.
 SUMMARY OF THE INVENTION
 However, in the above-described previously proposed vehicular run
 controlling apparatus, for example, a wholly different function of
 releasing the control is provided in a brake which is, in nature, a
 deceleration function. Hence, although the following control is released
 in response to a vehicular driver's light depression of the brake pedal
 due to a narrowing of the inter-vehicle distance from the vehicle to the
 preceding vehicle during the following control of the vehicle, the
 vehicular driver does not often recognize (or often has no consciousness)
 that the following control has been released.
 In addition, although the following control is automatically released in a
 case where the vehicular velocity is remarkably decreased and exceeds a
 vehicular deceleration controllable vehicular velocity range due to a
 traffic congestion, the vehicular driver does not often recognize that
 this control is released automatically since no vehicular driver's
 manipulation for the vehicle is involved.
 As described above, such a state transition (hereinafter, also referred to
 as a mode transition) from one control state (mode) to another control
 state (mode) that the vehicular driver does not often recognize sometimes
 makes a mismatch to the vehicular driver's sense of vehicular driving.
 It is, therefore, an object of the present invention to provide vehicular
 run controlling apparatus and method for an automotive vehicle which can
 positively inform the vehicular driver of such a state transition from one
 control state to another control state that would be deemed not to be
 recognized by the vehicular driver when the above-described state
 transition occurs.
 According to one aspect of the present invention, there is provided a
 vehicular run controlling apparatus for an automotive vehicle, comprising:
 a vehicular velocity detector to detect a vehicular velocity of the
 vehicle; a vehicular running environment detector to detect a running
 environment surrounding the vehicle; an informing device; and a vehicular
 run controller to perform a vehicular run control on the basis of the
 vehicular velocity detected by the vehicular velocity detector and the
 running environment detected by the vehicular running environment
 detector, the vehicular run controller having at least two control modes
 of a control wait mode and a vehicular run mode and including: a vehicular
 run control setter to set whether the vehicular run control should be
 started; and a mode transition instructor to instruct a mode transition
 from one control mode to another control mode in the vehicular run
 controller according to a vehicular driver's will, the vehicular run
 controller falling in a state of the vehicular run control when a start of
 the vehicular run control by means of the vehicular run controller is set
 through the vehicular run control setter, falling in a halt state of the
 vehicular run control when a release of the vehicular run control is set
 through the vehicular run control setter, carrying out the mode transition
 from one control mode to the other control mode when the mode transition
 from the one control mode to the other control mode is instructed through
 the mode transition instructor and when a predetermined condition is
 established during the vehicular run control irrespective of the vehicular
 driver's will, and informing the vehicular driver through the informing
 device of an occurrence of the mode transition from the one control mode
 to the other control mode when the mode transition from the one control
 mode to the other control mode occurs.
 According to another aspect of the present invention, there is provided a
 vehicular run controlling method for an automotive vehicle comprising:
 detecting a vehicular velocity of the vehicle; detecting a running
 environment surrounding the vehicle; providing an informing device; and
 providing a vehicular run controller to perform a vehicular run control on
 the basis of the detected vehicular velocity and the detected running
 environment, the vehicular run controller having at least two control
 modes of a control wait mode and a vehicular run mode and including: a
 vehicular run control setter to set whether the vehicular run control
 should be started; and a mode transition instructor to instruct a mode
 transition from one control mode to another control mode in the vehicular
 run controller according to a vehicular driver's will, the vehicular run
 controller falling in a state of the vehicular run control when a start of
 the vehicular run control by means of the vehicular run controller is set
 through the vehicular run control setter, falling in a halt state of the
 vehicular run control when a release of the vehicular run control is set
 through the vehicular run control setter, carrying out the mode transition
 from one control mode to the other control mode when the mode transition
 from the one control mode to the other control mode is instructed through
 the mode transition instructor and when a predetermined condition is
 established during the vehicular run control irrespective of the vehicular
 driver's will, and informing the vehicular driver through the informing
 device of an occurrence of the mode transition from the one control mode
 to the other control mode when the mode transition from the one control
 mode to the other control mode occurs.
 This summary of the invention does not necessarily describe all necessary
 features so that the invention may also be a sub-combination of these
 described features.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Reference will hereinafter be made to the drawings in order to facilitate a
 better understanding of the present invention.
 (First Embodiment)
 FIG. 1A shows a rough configuration representing a rear-wheel driven
 vehicle to which a first preferred embodiment of a vehicular following
 controlling apparatus according to the present invention is applicable.
 In FIG. 1A, 1FL and 1FR denote front left and right road wheels as
 non-driven wheels and 1RL and 1RR denote rear left and right road wheels
 as driven wheels.
 Rear left and right road wheels 1RL and 1RR are rotationally driven to
 which a driving force (or prime mover) of an engine 2 is transmitted via
 an automatic transmission 3, a propeller shaft 4, a final speed-reduction
 unit 5, and a wheel axle 6.
 A disc brake 7 is installed on each of front and rear left and right road
 wheels 1FL, 1FR, 1RL, and 1RR to develop a braking force and a braking
 liquid pressure (a brake hydraulic) to each disc brake 7 is controlled by
 means of a brake controller 8.
 It is noted that brake controller 8 develops the braking liquid (oil)
 pressure in accordance with a depression depth of a brake pedal 16 (which
 corresponds to a brake manipulator, in a broad sense of term) as will be
 described later and in accordance with target braking pressure P.sub.B *
 from a following controller 30.
 An Engine output controller 9 is disposed on engine 2 to control an output
 of engine 2. Engine output controller 9 has adopted one of two engine
 output control methods, i.e., a method of adjusting opening angle TH of a
 throttle valve of engine 2 to control an engine speed and another method
 of adjusting an opening angle of an idle control valve of engine 2 to
 control an idling speed of engine 2. In the first embodiment, the method
 of adjusting the opening angle of the engine throttle valve is adopted.
 A transmission (A/T) controller 10 is disposed on automatic transmission 3
 to control a gear shift position of transmission 3. Transmission
 controller 10 is so arranged that when an up-shift/down-shift command
 value TS is received from following controller 30, the gear shift position
 of transmission 3 is controlled to be shifted up or shifted down, as will
 be described later.
 On the other hand, an inter-vehicle distance sensor 12 constituted by a
 radar unit is disposed on a front lower end portion of the vehicle which
 sweeps a laser light beam in a front width-wise direction (so-called,
 detection zone) of the vehicle and receives a reflected light beam from an
 object which is a preceding vehicle running ahead of the vehicle at the
 same traffic lane as the vehicle. Inter-vehicle distance sensor 12 detects
 an inter-vehicle distance from the vehicle to the preceding vehicle as
 inter-vehicle distance detecting means covered by vehicular running
 environment detecting means.
 In the vehicle shown in FIG. 1A, two wheel velocity sensors 13FL and 13FR
 which detect wheel velocities of, for example, front left and right road
 wheels 1FL and 1FR which are the non-driven wheels, accelerator switch 15
 which detects a depression of accelerator pedal 14 (which corresponds to
 an accelerator in a broad sense of term), a brake switch 17 which detects
 a depression of brake pedal 16, a braking pressure sensor 16 which detects
 a braking pressure outputted from brake controller 8, a main switch
 SW.sub.M which serves as a vehicular run setter to select whether a
 following control should be carried out or not, a set switch SW.sub.S
 which serves to set a set vehicular velocity, a cancel switch SW.sub.C
 which serves as release instructing means, and a Drive range detecting
 switch SW.sub.D which is turned on when a Drive ("D") range of automatic
 transmission 3 is selected through a select lever are disposed. It is
 noted that set switch SW.sub.S, cancel switch SW.sub.C, and Drive range
 detecting switch SW.sub.D constitute mode transition instructing means
 defined in the claims.
 Main switch SW.sub.M includes a momentary type exchange switch 20 which is
 operated in accordance with the vehicular driver's will and self-hold type
 relay circuit 21. One end of exchange switch 20 is connected to a battery
 B via ignition switch SWIG.
 Exchange switch 20 is arranged as follows:
 When exchange switch 20 is turned off, a junction between a first input
 terminal ti1 to which switch signal SIG is inputted and an output terminal
 t0 is in an interrupted state. When switch 20 is in a neutral position,
 the junction between a second input terminal ti2 to which a power supply
 from a relay circuit 21 is inputted and output terminal t0 is in a
 connection state. When switch 20 is turned on, first and second input
 terminals ti1 and ti2 and output terminal t0 are in the connection state.
 Relay circuit 21 includes a normally open contact s1 and relay coil RL. One
 end of normally open contact s1 is connected to ignition switch SW.sub.IG
 and the other end thereof is connected to following controller 30 as will
 be described later directly and via set switch SW.sub.S and to second
 input terminal ti2 of exchange switch 20. One end of relay coil RL is
 connected to the output terminal of exchange switch 20 and the other end
 thereof is grounded.
 Following controller 30 receives each detection signal from inter-vehicle
 distance sensor 12, wheel velocity sensors 13FL and 13FR, accelerator
 switch 15, brake switch 17, and braking pressure sensor 18, respective
 switch signals S.sub.M, S.sub.SET, and S.sub.CAN from main switch
 SW.sub.M, switch signal S.sub.M indicating the selection of whether the
 following control should be carried out, set switch SW.sub.S, and cancel
 switch SW.sub.C, and a switch signal S.sub.DR from Drive range detecting
 switch SW.sub.D. Following controller 30, in accordance with a state
 transition diagram representing transition states on the following control
 shown in FIG. 2, has three control states (modes), viz., a control wait
 mode WM; a following mode FM; and a control halt mode. It is noted that,
 in following mode FM, following controller 30 controls the vehicular
 velocity through brake controller 8, engine output controller 9, and
 transmission controller 10 in such a manner that detected vehicular
 velocity Vs is made substantially equal to set vehicular velocity
 V.sub.SET when the preceding vehicle is not trapped by means of
 inter-vehicle distance sensor 12 and an actual inter-vehicle distance L is
 made substantially equal to a target inter-vehicle distance L* when
 preceding vehicle is trapped by means of inter-vehicle distance sensor 12.
 In the control halt mode, following controller 30 takes a priority on the
 vehicular driver's manipulation higher than the following control mode
 with the control in following mode FM halted and a predetermined condition
 established. Following controller 30 is, thus, managed to fall into the
 three control modes described above in accordance with predetermined
 transition conditions.
 In details, when main switch SW.sub.M is turned on from a turned-off state,
 following controller 30 enters control wait mode WM from a following run
 control stop state external to FIG. 2.
 Then, in control wait mode WM, the mode transition of following controller
 30 occurs from control wait mode WM to following mode FM when a first
 condition is established. The first condition is such that, in control
 wait mode WM, the gear range position of automatic transmission 3 is in
 the Drive range, the vehicle is running with brake switch 17 turned off
 and set switch SW.sub.S is in the turn off state.
 In addition, when, in following mode FM, a second condition is established,
 the mode transition from following mode FM to control halt mode RM occurs.
 The second condition is such that an acceleration manipulation by the
 vehicular driver occurs, viz., accelerator switch 15 is turned on with
 accelerator pedal 14 depressed.
 In addition, when, in control halt mode RM, a third condition is
 established, the mode transition from control halt mode RM to following
 mode FM occurs. The third condition is such that, in control halt mode RM,
 with accelerator pedal 14 depressed by the vehicular driver to perform a
 vehicular acceleration, accelerator pedal 14 is released so that
 accelerator switch 15 is turned off from the turn-on state.
 In addition, when, in following mode FM, a fourth condition is established,
 the mode transition from following mode FM to control wait mode WM occurs.
 The fourth condition is such that, in following mode FM, cancel switch
 SW.sub.C is turned on, the vehicular driver selects any other range than
 the Drive range through the select lever so that Drive range detecting
 switch SW.sub.D is turned off from its turned on state, brake pedal 16 is
 further depressed mode deeply (this is detected by braking pressure sensor
 18 as will be described later), or vehicular velocity Vs is decreased and
 exceeds a predetermined velocity value.
 Furthermore, when, in control halt mode RM, a fifth condition is
 established, the mode transition from control halt mode RM to control wait
 mode WM occurs. The fifth condition is such that, in control halt mode RM,
 cancel switch SW.sub.C is turned on with accelerator pedal 14 depressed by
 the vehicular driver to accelerate the vehicle, the vehicular driver
 selects any other range than the Drive range through the select lever so
 that Drive range detecting switch SW.sub.D is turned off, or vehicular
 velocity Vs is increased and exceeds another predetermined velocity value.
 When such a mode transition from the one control mode to another control
 mode that it tends to become insufficient for the vehicular driver to
 recognize the mode transition occurs, following controller 30 outputs an
 alarm signal AS to an informing device such as an alarm unit 31 which
 produces an alarm sound.
 Next, an operation of the first preferred embodiment of the vehicular run
 controlling apparatus will be described with reference to a following
 control procedure executed in following controller 30 and shown in FIG. 3.
 The following control procedure shown in FIG. 3 is executed as a main
 program routine. It is noted that following controller 30 includes a
 microcomputer whose basic structure is shown in FIG. 1B. In FIG. 1B, the
 microcomputer has an MPU 30a (MircoProcesser Unit), an interrupt
 controller, a DMA (Direct Memory Access) controller, a RAM 30b (Random
 Access Memory), a ROM 30c (Read Only Memory), an I/O interface 30d having
 an input port, an output port, and an I/O controller, an address bus 30e,
 a data bus 30f, and a control bus 30g.
 Following controller 30 determines whether the present control mode is in
 control wait mode WM. If Yes at a step S1 (control wait mode), the routine
 goes to a step S2. At step S2, following controller 30 executes such a
 transition destination selection procedure as to select to which mode the
 mode transition from control wait mode WM occurs and the routine goes to a
 step S6. The transition destination selection procedure executed at step
 S2 will be described later (as a subroutine).
 In addition, if No at step S1, the routine goes to a step S3. At step S3,
 following controller 30 determines if the present control mode is
 following mode FM. If Yes at step S3, the routine goes to a step S4. At
 step S4, following controller 30 executes such another transition
 destination selection procedure as to select to which mode the mode
 transition from following mode FM occurs. The other transition destination
 selection procedure at step S4 will be described later (as a subroutine).
 Furthermore, if No at step S3, the routine goes to a step S5 since the
 present control mode is determined as remaining control halt mode RM. At
 step S5, following controller 30 executes such a still another transition
 destination selection procedure as to select to which mode the transition
 from control halt mode RM occurs. This transition selection destination
 procedure at step S5 will be described later (as a subroutine).
 Thus, after any one of the above-described transition destination selection
 procedures at respectively corresponding steps of S2, S4, and S5 is ended,
 the routine goes to a step S6.
 At step S6, following controller 30 determines if the present control mode
 is in control wait mode WM in the same manner as the case of step S1.
 If Yes at step S6 (control wait mode WM), the routine goes to a step S7. At
 step S7, following controller 30 executes a control wait mode procedure
 and, thereafter, this procedure is ended (the main routine is ended and
 returns to step S1). If No at step S6 (not in control wait mode WM), the
 routine goes to a step S8.
 At step S8, following controller 30 determines if the present control mode
 is following mode FM in the same manner as described at step S3. If Yes at
 step S8 (the following mode), the routine goes to a step S9. At step S9,
 following controller 30 executes a following mode procedure and,
 thereafter, this procedure is ended (the main routine is returned to step
 S1).
 If No at step S8 (not the following mode), the routine goes to a step S10.
 At step S10, following controller 30 executes a control halt mode
 procedure and, thereafter, this procedure is ended and main routine is
 returned to step S1.
 The transition destination selection procedure from control wait mode WM at
 step S2 (the subroutine at step S2) is shown in FIG. 4.
 That is to say, at a step S11, following controller 30 determines whether
 switch signal S.sub.DR of the Drive ("D ") range detecting switch SW.sub.D
 is turned on so as to determine whether the gear range position of
 automatic transmission 3 is in the Drive range.
 If following controller 30 determines that the state of switch signal
 S.sub.DR is in the turned-off state so that the range position of
 automatic transmission 3 is not in the Drive range (No) at step S11, the
 routine goes to a step S12. At step S12, following controller 30 maintains
 the control mode in control wait mode WM, the routine is returned to the
 main routine, and the main routine is ended.
 If Yes at step S11, viz., switch signal SW.sub.D is turned on to indicate
 that the gear range position is in the Drive range, the routine in FIG. 4
 goes to a step S13.
 At step S13, following controller 30 determines if vehicular velocity Vs
 calculated on the basis of wheel velocity signals from front left and
 right wheel velocity sensors 13FL and 13FR as will be described later is
 equal to or higher than lowest limit value V.sub.L of a following
 controllable vehicular velocity range.
 If Vs&lt;V.sub.L at step S13 (No), the routine goes to a step S12. If Yes
 at step S13 (Vs.gtoreq.V.sub.L), the routine goes to a step S14.
 At step S14, following controller 30 determines if vehicular velocity Vs is
 equal to or lower than an upper limit value V.sub.H of the following
 controllable vehicular velocity range. If Vs&gt;V.sub.H (No) at step S14,
 the routine goes to step S12. If Vs.ltoreq.V.sub.H (Yes) at step S14, the
 routine goes to a step S15.
 At step S15, following controller 30 determines if brake pedal 16 is
 depressed so that switch signal S.sub.B is in the turn on state. If switch
 signal S.sub.B is in the turned on state (Yes) at step S15, the routine
 goes to step S12.
 If No (S.sub.B is in the turn off state) at step S15, the routine goes to a
 step S16.
 At step S16, following controller 30 determines if set switch S.sub.SET is
 turned on.
 If SW.sub.S is turned on (Yes) at step S16, the routine goes to a step S17.
 If No (SW.sub.S is in the turned off state) at step S16, the routine goes
 to step S12.
 At step S17, following controller 30 changes the present control mode to
 following mode FM, the routine is returned to the main routine, and the
 main routine is ended.
 It is noted that steps S11 and S13 through S16 serve to determine whether
 the first condition is established.
 In addition, FIG. 5 shows the other transition destination selection
 procedure in following mode FM at step S4 in the following control
 procedure shown in FIG. 3 (as a subroutine).
 At step S21, following controller 30 determines whether switch signal
 S.sub.CAN of cancel switch S.sub.WC is turned on. If switch signal
 S.sub.CAN is turned on (Yes) at step S21 (SW.sub.C ON), the routine goes
 to a step S22.
 At step S22, following controller 30 changes the present control mode to
 control wait mode WM and, then, the routine is ended.
 If switch signal S.sub.CAN indicates the turned-off state of cancel switch
 SW.sub.C (No) at step S21, the routine goes to a step S23.
 At step S23, following controller 30 determines if the gear range position
 of automatic transmission 3 has changed from the Drive range to another
 range according to the state of switch signal S.sub.DR of Drive range
 detecting switch SW.sub.D. If switch signal S.sub.DR indicates the
 turned-off state (Yes) at step S23, following controller 30 determines
 that the range position of automatic transmission 3 has been changed from
 the Drive range to another range and the routine goes to a step S24.
 At step S24, follow-run controller 30 outputs alarm signal AS having a
 logical value of "1" to alarm unit 31 and the routine goes to step S22.
 If switch signal S.sub.DR remains in the turned-on state (No) at step S23,
 following controller 30 determines that the range position of automatic
 transmission 3 remains at the Drive range and the routine goes to a step
 S25.
 At step S25, following controller 30 reads a present braking pressure
 P.sub.B (n) detected by brake pressure sensor 18 and compares read braking
 pressure P.sub.B (n) with target braking pressure P.sub.B * to determine
 if a vehicular driver's deeper depression on brake pedal 16 occurs.
 If brake pedal 16 is depressed more deeply (Yes) at step S25, the routine
 goes to above-described step S24. If No at step S25, the routine goes to a
 step S26.
 At step S26, following controller 30 determines if vehicular velocity Vs is
 equal to or lower than lowest limit value V.sub.L of the following
 controllable vehicular velocity range.
 If Vs.ltoreq.V.sub.L (Yes) at step S26, the routine goes to step S24.
 If Vs&gt;V.sub.L (No) at step S26, the routine goes to step S27.
 At step S27, following controller 30 determines whether switch signal
 S.sub.A of accelerator switch 15 is in the on state to determine if the
 vehicular driver has depressed accelerator pedal 14.
 If switch signal S.sub.A is in the on state (yes), the routine goes to a
 step S28 in which the present control mode is changed to control halt mode
 RM and the present routine is ended. If switch signal S.sub.A is in the
 off state (No) at step S27, the routine goes to a step S29 in which the
 present following mode FM is maintained (remains unchanged) and the
 present routine is ended.
 In the other transition destination selection procedure shown in FIG. 5,
 the contents of steps S21 through S26 serve to determine if the second
 condition is established and the contents of steps S21 through S27 serve
 to determine if the fourth condition is established.
 Then, FIG. 6 shows the still other transition destination selection
 procedure from control halt mode RM at step S5 shown in FIG. 3 (as a
 subroutine).
 As shown in FIG. 6, at a step S31, following controller 30 determines
 whether the range position of automatic transmission 3 is at the Drive
 range according to whether switch signal S.sub.DR of Drive range detecting
 switch SW.sub.D is in the on state or changed to the off state. If switch
 signal S.sub.DR changed from the on state to the off state (No) at step
 S31, following controller 30 determines that the range position at
 automatic transmission 3 has changed from the Drive range and the routine
 goes to a step S32.
 At step S32, following controller 30 outputs alarm signal AS having the
 logical value of "1" to alarm unit 31 and the routine goes to a step S33
 in which the present control mode is changed to control wait mode WM and
 the present routine is ended. If switch signal S.sub.DR remains in the on
 state (yes) at step S31, the routine goes to a step S34.
 At step S34, following controller 30 determines whether the vehicular
 driver has depressed accelerator pedal 14 according to whether switch
 signal S.sub.A of accelerator switch 15 is in the on state. If accelerator
 switch S.sub.A is in the off state (No) at step S34, following controller
 30 determines that the accelerator manipulation is ended and the routine
 goes to a step S35. At step S35, following controller 30 changes the
 present control mode to following mode FM and the present routine is
 ended.
 If switch signal S.sub.A is in the on state (yes) at step S34, following
 controller 30 determines that the acceleration manipulation is continued
 and the routine goes to a step S36.
 At step S36, following controller 30 determines if vehicular velocity Vs is
 equal to or lower than upper limit value V.sub.H of the following
 controllable vehicular velocity range. If Vs&gt;V.sub.H (No), viz.,
 vehicular velocity Vs is in excess of upper limit value V.sub.H at a step
 S36, the routine goes to step S32. If Vs.ltoreq.V.sub.H (Yes) at step S36,
 the routine goes to a step S37.
 At step S37, following controller 30 determines if switch signal S.sub.CAN
 of cancel switch SW.sub.C is in the on state. If switch signal S.sub.CAN
 indicates the turned off state (No) at step S37, the routine goes to a
 step S38 in which present control halt mode RM is maintained and the
 present routine is ended.
 If switch signal S.sub.CAN indicates the turn-on state (Yes) at step S37,
 the routine goes to step S33.
 In the transition destination selection procedure shown in FIG. 6, the
 contents of steps S31, S35, and S36 serve to determine if the fifth
 condition is established and the contents of steps S31 and S34 serve to
 determine whether the third condition is established.
 Furthermore, FIG. 7 shows the control wait mode procedure at step S7 shown
 in the following control procedure shown in FIG. 3 (as a subroutine).
 As shown in FIG. 7, at a step S41, following controller 30 measures the
 number of pulses per unit time or an elapsed time between each pulse of a
 detection pulse train signal detected by means of wheel velocity sensors
 13FL and 13FR and retrieves a predetermined tire outer diameter from a
 memory to calculate wheel velocities V.sub.FL and V.sub.FR and to
 calculate an average value of V.sub.FL and V.sub.FR to derive vehicular
 velocity Vs.
 At step S42, following controller 30 reads at least the state of switch
 signal S.sub.DR of Drive range detecting switch SW.sub.D installed on the
 Drive range position of the select lever of automatic transmission 3 to
 change over the range of automatic transmission 3.
 At step S43, following controller 30 reads the state of switch signal
 S.sub.B of brake switch 17. At a step S44, following controller 30 reads
 the state of switch signal S.sub.SET of set switch SW.sub.S.
 Then, the routine shown in FIG. 7 is ended.
 FIG. 8 shows the following mode procedure at step S9 in the following
 control procedure shown in FIG. 3 (as a subroutine).
 At a step S51, following controller 30 reads the state of switch signal
 S.sub.CAN of cancel switch SW.sub.C At a step S52, following controller 30
 reads inter-vehicle distance L detected by inter-vehicle distance sensor
 12. At a step S53, following controller 30 measures vehicular velocity Vs
 in the same way as described at step S41 shown in FIG. 7. At a step S54,
 following controller 30 reads the state of switch signal S.sub.DR of Drive
 range detecting switch SW.sub.D.
 At a step S55, following controller 30 reads the state of switch signal
 S.sub.B of brake switch 17.
 At a step S56, following controller 30 reads the state of switch signal
 S.sub.A of accelerator switch 15. At a step S57, following controller 30
 calculates target inter-vehicle distance L* using the following equation
 (1) on the basis of vehicular velocity Vs when inter-vehicle distance
 sensor 12 traps the preceding vehicle, calculates target vehicular
 velocity V* on the basis of a deviation between target inter-vehicle
 distance L* and inter-vehicle distance L, when inter-vehicle distance
 sensor 12 traps the preceding vehicle, sets set vehicular velocity
 V.sub.SET set by the vehicular driver as target vehicular velocity V* when
 no preceding vehicle has been trapped, performs a vehicular velocity
 control procedure on the basis of calculated or set target vehicular
 velocity V*, and performs controls over brake controller 8, engine output
 controller 9, and automatic transmission controller 10.
EQU L*=Vs.multidot.V.sub.CF +T.sub.OF (1)
 In the equation (1), V.sub.CF denotes time duration (so-called, an
 inter-vehicle time duration) it takes for the vehicle to reach to position
 L.sub.0 (meters) behind the present preceding vehicle and T.sub.OF denotes
 an offset time.
 It is noted that, in the vehicular velocity control procedure, vehicular
 velocity Vc as an object to be controlled is selected from a smaller one
 of calculated target vehicular velocity V* and set vehicular velocity
 V.sub.SET set by the vehicular driver [Vc=min(V*, V.sub.SET)].
 n, either a vehicular velocity servo system through a robust model matching
 control technique and constituted by a model matching compensator and a
 robust compensator as described in a U.S. Pat. No. 5,959,572 issued on
 Sep. 28, 1999 (the disclosure of which is herein incorporated by
 reference) or a generally available feedback control system is applied so
 that a driving force command value F.sub.OR and a disturbance estimated
 value dv to make vehicular velocity Vs substantially equal to vehicular
 velocity Vc of the object to be controlled, target driving force F* which
 is a deviation of command value F.sub.OR and estimated value dv are
 calculated, and the vehicular velocity is controlled through the control
 over brake controller 8, engine output controller 9, and/or automatic
 transmission (A/T) controller 10.
 Furthermore, FIG. 9 shows the control halt mode procedure at step S10 in
 the following control procedure in FIG. 3.
 As shown in FIG. 9, at a step S61, following controller 30 calculates
 vehicular velocity Vs. At a step S62, switch signal S.sub.DR of Drive
 range detecting switch S.sub.WD is read. At a step S63, switch signal
 S.sub.A of the accelerator switch 15 is read. At a step S64, switch signal
 S.sub.CAN of cancel switch S.sub.WC is read and the present routine is
 ended.
 The following control procedure in FIG. 3 corresponds to the following
 control means. The contents of step S53 in FIG. 8, the contents of step
 S61 in FIG. 9, and vehicular velocity sensors 13FL and 13FR correspond to
 wheel velocity detecting means.
 Hence, suppose now that ignition switch SW.sub.IG is turned off, the select
 lever is placed in a parking range ("P") range and a parking brake (not
 shown) is operated so that the vehicle is stopped together with the
 preceding vehicle. In this state, since the power to the following
 controller 30 falls in the control stop state.
 A vehicular occupant(s) gets on the vehicle under the control halt state,
 the power is supplied to following controller 30, and the control is
 started.
 At this time, since relay circuit 21 is in a non-bias state when ignition
 switch SW.sub.IG is turned off, main switch SW.sub.M is turned off.
 When the control is started by means of following controller 30, an
 initialization causes the control mode to be set in control wait mode WM
 and each switch and the sensor signals are read. However, the following
 control procedure shown in FIG. 3 is stopped.
 From the above-described state, exchange switch 20 of main switch SW.sub.M
 is placed from the neutral position to the ON position. Accordingly, relay
 circuit 21 is turned on so as to be in the self hold state. Even if
 exchange switch 20 is returned to the neutral (N) position, switch signal
 S.sub.M is continued to be on state.
 As described above, if main switch SW.sub.M is turned on, the following
 control procedure in FIG. 3 is started. At this time, control wait mode WM
 is initialized and the routine of FIG. 3 goes from a step S1 to a step S2.
 The transition destination selection procedure from control wait mode WM
 shown in FIG. 4 is executed. Since the range in automatic transmission 3
 is selected into parking range through the select lever, the routine goes
 from step S11 shown in FIG. 4 to step S12 in which the control wait mode
 is maintained.
 Thereafter, when the preceding vehicle is started, the depression of brake
 pedal 16 is released, and, then, the vehicle is started with accelerator
 pedal 15 depressed so that vehicular velocity Vs becomes equal to or
 higher than lowest limit value V.sub.L, the routine shown in FIG. 4 goes
 from step S13 to step S14. Since vehicular velocity Vs is equal to or
 lower than upper limit value V.sub.H, the routine goes further to step
 S15. Since brake pedal 16 is released, the routine goes to step S17 in
 which the present control mode is changed from the control wait mode to
 following mode FM. At this time, since set switch SW.sub.S is operated
 according to the vehicular driver's will, an alarm sound is not produced
 from alarm unit 31.
 In the following mode, since the preceding vehicle is trapped by means of
 inter-vehicle distance sensor 12, a target acceleration (/deceleration) is
 calculated in such a manner that inter-vehicle distance L is made
 substantially equal to target inter-vehicle distance L*. Therefore, target
 driving force F* (it is noted that the target driving force includes a
 target braking force since the target braking force is a negative value of
 the target driving force) indicates a positive value. When command value
 TH of the throttle valve of engine 2 as shown in FIG. 1A is outputted to
 engine output controller 9, the vehicle is started and is accelerated.
 In following mode FM, the preceding vehicle is decelerated or the preceding
 vehicle is interrupted from another traffic lane into the same traffic
 lane as the vehicle. Hence, since inter-vehicle distance L becomes
 narrower than target inter-vehicle distance L*, target driving force F*
 indicates a negative value.
 At this time, throttle opening angle command value TH indicates "0"
 representing a full closure state of the throttle valve opening angle of
 engine 2 and shift position signal TS which commands transmission
 controller 10 to issue, for example, a downshift command according to its
 necessity so that an engine braking force is increased and target braking
 pressure P.sub.B * which accords with target driving force F* is outputted
 so that the vehicular brake system becomes active and inter-vehicle
 distance L is made substantially equal to target inter-vehicle distance
 L*.
 If inter-vehicle distance L is placed in the vicinity to target
 inter-vehicle distance L*, shift position signal TS which commands an
 up-shift from the present gear position to transmission controller 10 and
 target braking pressure P.sub.B * is also decreased. If inter-vehicle
 distance L is made substantially equal to target inter-vehicle distance L*
 so that target driving force F* indicates a positive value, throttle
 opening angle command value TH is accordingly outputted to engine output
 controller 9 and the control is recovered to the driving force control
 state.
 In the inter-vehicle distance control state, if the inter-vehicle distance
 sensor 12 cannot trap the preceding vehicle, the vehicular velocity is
 controlled in such a manner that set vehicular velocity V.sub.SET set by
 the vehicular driver is made substantially equal to vehicular velocity Vs.
 In following mode FM, the preceding vehicle is decelerated due to a red
 light indication at a far-off intersection, target braking pressure
 P.sub.B * is outputted to maintain the vehicle at target inter-vehicle
 distance L* so that the vehicular deceleration control is carried out.
 Then, if vehicular velocity Vs is equal to or lower than lower limit value
 of V.sub.L in the transition destination selection procedure shown in FIG.
 5, the routine goes to step S24 in which alarm signal AS having the
 logical value of "1" is outputted to alarm unit 31 to produce the alarm
 sound. Then, the routine goes to step S22 shown in FIG. 5. At step S22,
 the control is recovered to control wait mode WM. Hence, the producing of
 the alarm sound can assure the vehicular driver to recognize that control
 is transferred to control wait mode WM without involvement of the
 vehicular driver's manipulation.
 In the same manner, in a case where the braking force is increased with
 brake pedal 16 depressed deeply, in following mode FM, the vehicular
 driver has carried out for the vehicle to be decelerated. Since the
 vehicular driver has not recognized that the brake pedal depression has
 its other function to release following mode FM, the routine goes to step
 S24. At step S24, the alarm sound is produced by means of alarm unit 31 so
 as to be enabled to assure the recognition by the vehicular driver that
 the mode transition to control wait mode WM occurs.
 Thereafter, if the preceding vehicle has started with the red light turned
 to a green light, the present control mode is recovered into following
 mode FM when the vehicular driver has depressed accelerator pedal 14 and
 set switch SW.sub.S is turned to ON, vehicular velocity Vs being
 accelerated and being equal to or higher than lower limit value V.sub.L,
 the vehicular driver's will causes the control mode to be recovered to
 following run mode FM.
 In addition, if the vehicular driver uses the select lever to select the
 range into a second ("2") speed range to effect the engine braking on the
 vehicle, switch signal SD of Drive range detecting switch SW.sub.D is
 turned off.
 In the transition destination selection procedure of FIG. 5, the routine
 goes from step S23 to step S24 so that the alarm sound is produced by
 means of alarm unit 31. Then, the routine goes to step S22 in which the
 control mode is changed to control wait mode WM. In this case, since the
 vehicular velocity driver's selection of the range to the "2" range means
 the vehicular deceleration manipulation, the vehicular driver may not
 recognize this deceleration manipulation has the other function to release
 following mode FM. Hence, the producing of the alarm sound through alarm
 unit 31 assures the vehicular driver to recognize that the mode transition
 to control wait mode WM has been carried out. In this case, the producing
 of the alarm sound through alarm unit 31 can assure the vehicular driver
 to recognize that the transition to control wait mode WM has occurred.
 On the other hand, the present following mode is transferred to control
 halt mode RM if the vehicular driver depresses accelerator pedal 14 so
 that accelerator switch 15 is turned on.
 Then, control halt mode RM is continued when the depression of accelerator
 pedal 14 is continued and vehicular velocity Vs is lower than upper limit
 value V.sub.H. However, if switch signal S.sub.A is turned off with
 accelerator pedal 14 released, the present routine shown in FIG. 6 goes
 from step S34 to step S35 in which the present mode is transferred to the
 following mode without the alarm sound produced by alarm unit 31.
 In addition, when, in control halt mode RM, the vehicular driver selects
 the range by the select lever other than the Drive range or depresses
 accelerator pedal 14 so that vehicular velocity Vs is equal to or higher
 than upper limit value V.sub.H, the vehicular driver does not often
 recognize that the accelerator pedal depression and the vehicular velocity
 which is equal to or higher than upper limit value V.sub.H. Hence, the
 alarm sound is produced through alarm unit 31 so that it is assured that
 the vehicular driver can recognize that the mode transition from the
 present mode to control wait mode WM occurs.
 On the other hand, since, in control halt mode RM, cancel switch SW.sub.C
 is turned on, the vehicular driver recognizes that the mode transition
 from control halt mode RM to control wait mode WM has occurred. Hence, the
 routine of FIG. 6 goes from step S26 to step S33 directly so that the mode
 transition to control wait mode WM occurs without the producing of the
 alarm sound through alarm unit 31.
 As described above, in a case where such a mode transition that the
 vehicular driver's recognition becomes insufficient (for example, the mode
 transition such that the driver's manipulation is not involved, the
 function to transfer the one mode to the other mode is provided in a
 normal function with the vehicular driver's manipulation involved, in the
 first embodiment, the alarm sound is produced through alarm unit 31.
 Hence, it can be assured that the occurrence of the mode transition is
 recognized by the vehicular driver.
 In addition, if the mode transition occurs according to the vehicular
 driver's will, the alarm sound is not produced by means of alarm unit 31.
 Hence, it can be suppressed that the vehicular driver is troubled by the
 alarm sound.
 It is noted that, in the first embodiment, target inter-vehicle distance L*
 is calculated on the basis of vehicular velocity Vs. However, in
 inter-vehicle distance L may be differentiated through a band-pass
 filtering or a high-pass filtering to calculate a relative velocity
 .DELTA.V, relative velocity .DELTA.V may be added to vehicular velocity Vs
 to calculate a vehicular velocity of preceding vehicle Vt, and, then,
 target inter-vehicle distance L* may be calculated on the basis of
 vehicular velocity Vt of the preceding vehicle.
 It is also noted that, in the first embodiment, the laser radar is applied
 to the inter-vehicle distance detecting means (inter-vehicle distance
 sensor 12). However, the inter-vehicle distance may be calculated using a
 millimeter wave radar, or alternatively using an image processing of an
 image photographed by a stereoscopic camera.
 It is also noted that although, in the first embodiment, the vehicular
 velocity is calculated from the wheel velocities of the front road wheels,
 viz., the non-driven wheels, a vehicular body velocity may be estimated
 from four wheel velocities including the driven wheels (rear road wheels
 1RR and 1RL). Furthermore, a revolution velocity on an output axle of
 automatic transmission 3 may be used to measure the vehicular velocity.
 (Second Embodiment)
 A second preferred embodiment of the vehicular run controlling apparatus
 according to the present invention will be described with reference to
 FIGS. 10 through 15.
 In the second embodiment, such an automatic stop mode that the vehicle is
 held in the stop state with a predetermined braking force held is added to
 the following control procedure in the above-described first embodiment,
 as shown in FIG. 10.
 That is to say, when, in following mode FM such sixth condition that
 inter-vehicle distance L is equal to or shorter than predetermined
 distance value L.sub.0 and vehicular velocity Vs is equal to or lower than
 lower limit value V.sub.L is established, the present mode viz., FM is
 transferred to automatic stop mode SM. When, in control wait mode WM, such
 a seventh condition that the gear range position of automatic transmission
 3 is in the Drive range, the vehicle is stopped, and set switch SW.sub.S
 is turned on with brake pedal 16 depressed is established, the control
 wait mode is changed to automatic stop mode SM. When, in automatic stop
 mode SM, such an eighth condition that control switch SW.sub.C is turned
 on, the range of automatic transmission 3 is selected from the Drive range
 ("D") to any other range, brake pedal 16 is depressed mode deeply, or
 accelerator switch 15 is in the turn on state is established, automatic
 stop mode SM is changed to control wait mode WM.
 FIGS. 11 through 15 shows processing routines executed in following
 controller 30 in the case of the second embodiment. The hardware structure
 in the second embodiment is the same as described in the first embodiment
 shown in FIGS. 1A and 1B.
 FIG. 11 shows the main routine in the case of the second embodiment. The
 same-numbered steps (S1 through S10) as described in the first embodiment
 shown in FIG. 3 are carried out in the same way as shown in FIG. 3.
 The determination result in step S3 indicates that the mode is not in
 following mode FM (No), the routine in FIG. 11 goes to a step S71.
 At step S71, following controller 30 determines if the present mode falls
 in control halt mode RM.
 If the present mode is the control halt mode (Yes) a step S71, the routine
 goes to step S5.
 If the present mode is not in the control halt mode (No) at step S71, the
 routine goes to a step S72.
 At step S72, following controller 30 executes the transition destination
 selection procedure from automatic stop mode SM as shown in FIG. 14.
 Thereafter, the routine goes to step S6.
 In addition, if the result of the determination at step S8 indicates that
 the present mode is not following mode (FM) (No), the routine goes to step
 S73.
 At step S73, following controller 30 determines if the present mode is
 control halt mode RM.
 If the present mode is the control halt mode (Yes) at step S73, the routine
 goes to step S10.
 If the present mode is not control halt mode (No) at step S73, the routine
 goes to a step S74.
 At step S74, following controller 30 executes the automatic stop mode
 procedure shown in FIG. 15.
 Since, at the steps other than those described above, following controller
 30 executes the same processes as those described with reference to FIG.
 3, the detailed description thereof will herein be omitted.
 FIG. 12 shows the transition destination selection procedure from control
 wait mode WM at step S2 in FIG. 11.
 As shown in FIG. 12, at step S81, following controller 30 determines if the
 gear range of automatic transmission 3 is selected to the Drive ("D")
 range according to whether switch signal S.sub.DR of Drive range detecting
 switch SW.sub.D is turned on.
 If switch signal S.sub.DR is in the off state (No) at step S81, the routine
 goes to a step S82.
 At step S82, following controller 30 maintains control wait mode WM and the
 present routine is ended.
 If switch signal S.sub.DR is turned on (yes) at step S81, the routine goes
 to a step S83.
 At step S83, following controller 30 determines if the vehicle is stopped
 according to whether the vehicular velocity Vs indicates "0". If Vs=0
 (Yes) at step S83, the routine goes to a step S84.
 At step S84, following controller 30 determines whether the vehicular
 driver has depressed brake pedal 16 according to whether switch signal
 S.sub.R of brake switch 17 is turned on.
 If switch signal S.sub.B is turned on (Yes) at step S84, the routine goes
 to a step S85.
 At step S85, following controller 30 determines whether set switch SW.sub.S
 is turned on.
 If set switch SW.sub.S is turned on (Yes) at step S85, the routine goes to
 a step 586. If set switch SW.sub.S is turned off (No) at step S85, the
 routine goes to step S82.
 At step S86, following controller 30 changes the control mode from control
 wait mode WM to automatic stop mode SM. Then, the routine is ended.
 On the other hand, if the result of determination at step S83 indicates
 that Vs&gt;0, viz., the vehicle is running, the routine goes to a step
 S87.
 At step S87, following controller 30 has depressed brake pedal 16 in the
 same manner as described at step S84.
 If switch signal S.sub.B of brake switch SW.sub.B is turned on (Yes) at
 step S87, the routine goes to step S82.
 If switch signal S.sub.B is turned off (No) at step S87, the routine goes
 to a step S88.
 At step S88, following controller 30 determines if set switch SW.sub.S is
 turned on in the same way as described at step S85.
 If switch signal S.sub.SET of set switch SW.sub.S is turned off (No) at
 step S88, the routine goes to step S82.
 If switch signal S.sub.SET is turned on (Yes) at step S88, the routine goes
 to a step S89.
 At step S89, following controller 30 changes the present mode from control
 wait mode WM to following mode FM and the routine is ended.
 Furthermore, FIG. 13 shows the transition destination selection procedure
 from following mode FM at step S2 shown in FIG. 11.
 As shown in FIG. 13, step S26 described with reference to FIG. 5 in the
 first embodiment has been eliminated. In addition, if the result of
 determination at step S27 indicates that the vehicular driver has not
 manipulated accelerator pedal 14 and switch signal S.sub.A is turned off
 (No) at step S27, the routine goes to step S91.
 At step S91, following controller 30 determines whether inter-vehicle
 distance L is equal to or shorter than predetermined inter-vehicle
 distance value L.sub.0.
 If L.ltoreq.L.sub.0 (yes) at step S91, the routine goes to a step S92.
 If L&gt;L.sub.0 (No) at step S91, the routine goes to step S29.
 At step S92, following controller 30 determines if vehicular velocity Vs is
 equal to or lower than predetermined value V.sub.0 which is further lower
 than lower limit value V.sub.L of the following controllable vehicular
 velocity range.
 At step S93, following controller 30 changes the present mode to automatic
 stop mode SM.
 The contents of the other steps than those described above are the same as
 those described with reference to FIG. 5 and the detailed description of
 the same numbered steps as those in FIG. 5 will herein be omitted.
 Next, FIG. 14 shows the transition destination selection procedure from
 automatic stop mode SM at step S72 in FIG. 11.
 As shown in FIG. 14, following controller 30 determines whether switch
 signal S.sub.CAN of cancel switch SW.sub.C is turned on. If switch signal
 S.sub.CAN is turned on (Yes) at a step S101, the routine goes to a step
 S102. At step S102, following controller 30 changes the present control
 mode to control wait mode WM and the present routine is ended.
 If switch signal S.sub.CAN is turned off (No) at step S101, the routine
 goes to a step S103.
 At step S103, following controller 30 determines whether the gear range
 position has been changed according to whether switch signal S.sub.DR of
 Drive range detecting Switch SW.sub.D is turned off. If switch signal
 S.sub.DR is turned off (No) at step S103, following controller 30
 determines that the range position of automatic transmission 3 has been
 changed and present routine goes to a step S104. At step S104, following
 controller 30 outputs alarm signal AS having the logical value of "1" to
 alarm unit 31 and the routine goes to step S102. If switch signal S.sub.DR
 remains on (No) at step S103, the routine goes to a step S105.
 At step S105, following controller 30 reads braking pressure P.sub.B (n)
 detected by means of braking pressure sensor 18, following controller 30
 determines if read braking pressure P.sub.B (n) is higher than target
 braking pressure P.sub.BS * when the vehicle is stopped so as to determine
 whether the vehicular driver has depressed brake pedal 16 more deeply.
 If the brake pedal is depressed more deeply (Yes) at step S105, the routine
 goes to a step S104. If brake pedal 16 is not depressed more deeply (No)
 at step S105, the routine goes to a step S106.
 At step S106, following controller 30 determines whether switch signal
 S.sub.A of accelerator switch 15 is turned on so as to determine whether
 the vehicular driver has depressed accelerator pedal 14. Then, the routine
 goes to step S107 if not depressed (switch signal S.sub.A is off (No)) at
 step S106. If depressed (yes) at step S106, the routine goes to step S104.
 At step S107, following controller 30 maintains the present mode at the
 automatic stop mode SM.
 In the transition destination selection procedure shown in FIG. 14, the
 contents of step S101, steps S103 through S106 serve to determine whether
 the above-described eighth conditions are established.
 FIG. 15 shows the detailed automatic stop mode procedure at step S74 in
 FIG. 11.
 As shown in FIG. 15, at step S111, following controller 30 reads
 inter-vehicle distance L detected by inter-vehicle distance sensor 12.
 At step S111, following controller 30 measures vehicular velocity Vs in the
 same manner as steps S47 shown in FIG. 7.
 At step S112, following controller 30 measures vehicular velocity Vs in the
 same manner as step S41 shown in FIG. 7.
 At step S113, switch signal S.sub.CAN of cancel switch SW.sub.C is read.
 At step S114, following controller 30 reads switch signal S.sub.DR of Drive
 range detecting switch SW.sub.D.
 At step S115, following controller 30 reads switch signal S.sub.B of brake
 switch S.sub.B.
 At step S116, following controller 30 reads switch signal S.sub.A of
 accelerator switch 15.
 At step S117, following controller 30 reads braking pressure P.sub.B
 detected by braking pressure sensor 18, outputs read braking pressure
 P.sub.B as target braking pressure P.sub.BS * to brake controller 8, sets
 opening angle .theta. of the throttle valve of engine 2 to "0", and
 outputs zero throttle valve command value to engine output controller 9.
 In the second embodiment, in the same way as the first embodiment, when the
 present control mode is transferred from automatic stop mode SM to control
 wait mode WM, its transition triggered causes are several factors.
 However, in a case where the vehicular driver turns on cancel switch
 SW.sub.C so that the mode is transferred to control wait mode WM, the
 information of the occurrence of the mode transition according to this
 case to the vehicular driver through alarm unit 31 is not carried out.
 On the contrary, the mode transition from automatic stop mode SM to control
 wait mode WM due to the range position change by the vehicular driver, the
 deeper depression of brake pedal 16, and the depression of accelerator
 pedal 14 is informed to the vehicular driver through alarm unit 31.
 Especially, in a case where accelerator pedal 14 is depressed so that the
 mode is transferred from automatic stop mode SM to control wait mode WM,
 the vehicular driver tends to forget that such an accelerator pedal
 depression as described above is the function peculiar to automatic stop
 mode SM (in the following mode, the control is not released even if
 accelerator pedal 14 is depressed and a vehicular start manipulation
 involves, for example, a double action (the control is, once, released and
 is reset). With these manipulations in mind, it may be considered that
 there are several cases of erroneous recognition by the vehicular driver.
 For example, suppose that, during automatic stop mode SM, the vehicular
 driver tries to make the vehicle start and depresses accelerator pedal 14
 and the vehicle is, then, running with the vehicular driver continued to
 depress accelerator pedal 14, for a while. At this time, in spite of the
 fact that the present mode is actually control wait mode WM, the vehicular
 driver mistakes that the present mode must be control halt mode RM (the
 vehicular pedal depression from following mode FM) and accelerator pedal
 14 is released. The vehicular driver has imagined that the control mode is
 returned to following mode FM so that the corresponding control is
 started. However, in this state, the information of the mode transition
 from automatic stop mode SM to control wait mode WM through alarm unit 31
 is carried out. Hence, the vehicular driver can be recognized without
 failure that the present mode is in control wait mode WM.
 Furthermore, when the vehicular driver tries to start the vehicle during
 automatic stop mode SM, lightly depressing and releasing accelerator pedal
 14, the vehicle is started to forward due to a creep phenomenon. At this
 time, in spite of the fact that the control mode is still in control wait
 mode WM, the vehicular driver often mistakes that the vehicle is started
 to forward so that the control is resumed and does not operate set switch
 SW.sub.S to turn it on. In this case, the information through alarm unit
 31 can prevent such a mistake as described above. Or, the vehicular driver
 often mistakes that the control must be resumed since the vehicle is
 started to be forwarded and mistakes that the vehicle must be stopped
 together with the preceding vehicle when the preceding vehicle is again
 decelerated and is about to be stopped. In this case, the information
 through alarm unit 31 can prevent the occurrence of the driver's mistakes.
 In addition, the following erroneous recognition situation can be supposed
 in a case where brake pedal 16 is depressed so that the mode is changed
 from automatic stop mode SM to control wait mode WM.
 That is to say, in spite of the fact that the vehicle is stopped in
 automatic stop mode SM, the vehicular driver himself has depressed brake
 pedal 16 to effect a manual brake due to the vehicular driver's customary
 action during the vehicular stop. This action causes the control to be
 released so that automatic stop mode SM is transferred to control wait
 mode WM. Hence, the automatic brake becomes ineffective. However, the
 vehicular driver does not notice this ineffective automatic brake but,
 expecting that the automatic stop would be continued, releases brake pedal
 16. At this time, the vehicle is started to forward due to the creep
 phenomenon.
 However, this case can positively be prevented from occurring according to
 the information of the occurrence of the mode transition from automatic
 stop mode SM to control wait mode WM to the vehicular driver through alarm
 unit 31.
 As described above, the occurrence of the mode transition from the one
 control mode to the other control mode can positively be informed to the
 vehicular driver in such cases that the vehicular driver mistakes the
 control states (modes).
 It is noted that, in the second embodiment, the mode transition from
 following mode FM to automatic stop mode SM is possible but the mode
 transition from automatic stop mode SM to following mode FM is inhibited.
 However, the mode transition from automatic stop mode SM to following mode
 FM may be enabled on such a transition condition that, in automatic stop
 mode SM, the preceding vehicle is started and the turn on of either the
 accelerator switch 15 or set switch SW.sub.S.
 It is also noted that, in each of the first and second embodiments, in a
 case where the mode transition occurs from following mode FM to control
 wait mode WM due to the occurrence of the range position from the Drive
 range to any other range or deeper depression on brake pedal 16, the alarm
 sound is always produced through alarm unit 31. However, it is not limited
 to this.
 In details, as shown in FIG. 16, if the result of the determination at step
 S23 indicates the occurrence of the range position change from the Drive
 range to another range and if the result of determination at step S25
 indicates the occurrence of the deeper depression of brake pedal 16, the
 routine may go to step S121 in which control flag FS is set to "1" and may
 go to step S22 without information through alarm unit 31.
 In this alternative case, in FIG. 17 which is the control wait mode
 maintaining procedure at step S82 in FIG. 12, at step S122 in FIG. 17,
 following controller 30 may determine if control flag FS is set to "1".
 If FS="1" (yes) at step S122, the routine shown in FIG. 17 may go to step
 S123.
 At step S123, following controller 30 may determine if neither accelerator
 switch 15 nor brake switch 17 is operated within a predetermined time
 duration. If neither accelerator switch 15 nor the brake switch is
 operated within the predetermined duration of time (Yes) at step S123,
 following controller 30 may determine that the transition to control wait
 mode WM is not recognized by the vehicular driver and the routine may go
 to step S124.
 At step S124, following controller 30 may output alarm signal AS to alarm
 unit 31 to produce the alarm sound. Then, the routine may go to step S125.
 At step S125, control flag FS may be reset to "0".
 At step S126, following controller 30 may maintain control wait mode WM and
 the routine shown in FIG. 17 may be ended.
 If control flag FS is reset to "0" at step S122 (No), the routine may jump
 to step S126.
 If either accelerator switch 15 or brake switch 17 is turned on within the
 predetermined duration of time (No) at step S123, the routine may jump to
 step S125 since following controller 30 may determine that the vehicular
 driver recognizes the present control mode.
 Furthermore, if control flag FS is reset to "0" when the routine shown in
 FIG. 12 may go to step S86 and to step S89, the alarm sound may be stopped
 if the vehicular driver recognizes that the mode transition from the
 following mode to the control wait mode occurs due to the added function
 although the driver's manipulation is involved. Hence, the vehicular
 driver can be prevented from feeling troublesome in the alarm sound.
 In each of the first and second embodiments, each disc brake 7 is applied
 to the vehicular brake system and its braking pressure is controlled.
 If a regenerative braking is carried out as in an electric motor, its
 regenerative braking force may be controlled.
 If en electric motor is used as a brake actuator, an electric control may
 be carried out.
 In summary, the braking force developed in the brake system may be
 controlled.
 In each of the first and second embodiments, automatic transmission 3 is
 installed on an output side of engine 2. However, the present invention is
 applicable to a continuously variable transmission (CVT) mounted vehicle.
 In each of the embodiments, the present invention is applicable to the
 rear-wheel driven vehicle. The present invention is also applicable to a
 front-wheel driven vehicle or to a four-wheel driven vehicle. Furthermore,
 the present invention is applicable to the electric vehicle in which an
 electric motor is mounted as the prime mover in place of engine 2 or to a
 hybrid vehicle in which both of engine 2 and the electric motor are used
 as the prime movers of the vehicle.
 In the application of the hybrid vehicle or the electric vehicle, an
 electric motor control may be added to or used in place of engine output
 controller 9.
 (Third Embodiment)
 Next, FIGS. 18 through 23 show a third preferred embodiment of the
 vehicular run controlling apparatus according to the present invention.
 In the third embodiment, the present invention is applicable to an
 automatic steering (maneuver) controlling apparatus which performs an
 automatic steering control, trapping a traffic lane, in place of the
 vehicular run controlling apparatus in each of the first and second
 embodiments.
 In the third embodiment, steering controller 50 as the vehicular run
 controlling means constituted by the microcomputer is installed as shown
 in FIG. 18.
 Steering controller 50 receives each detection signal of: white line
 detector 51 as the vehicular running environment detecting means;
 vehicular velocity sensor 52 as vehicular velocity detecting means; main
 switch SW.sub.M as the vehicular run control setting means; set switch
 SW.sub.S constituting mode transition instructing means; cancel switch
 SW.sub.C ; steering torque sensor 53 to detect a steering torque developed
 by steering a steering wheel by the vehicular driver; and steering angle
 sensor 54 that detects a steering angular displacement of a steering
 actuator to perform an arithmetic/logic operations on the basis of the
 detection signals. Then, steering controller 50 drivingly controls
 electric motor 55 as a steering actuator to perform an automatic steering
 operation for a vehicular steering system. During the occurrence of the
 mode change, steering controller 50 outputs alarm signal AS having the
 logical value of "1" to alarm unit 56 to inform the vehicular driver of
 the occurrence of the mode transition.
 White line detector 51 is constituted, for example, by a CCD (Charge
 Coupled Device) camera mounted in the vehicle.
 White line detector 51 recognizes a white line on a road surface which is
 photographed and calculates and outputs lateral deviation Y1 of an
 extension line of a center line perpendicular to a vehicular body width
 direction which is ahead of the vehicle by a predetermined spatial
 distance.
 In addition, steering controller 50 has been managed to divide the control
 mode into three modes of, as shown in FIG. 19, control wait mode WM,
 steering control mode FM in which controller 50 calculates target steering
 angle .theta.s* from lateral deviation yl received from white line
 detector 51 and vehicular velocity V of vehicular velocity sensor 52 and
 controls electric motor 55 so that target steering wheel .theta.s* is made
 substantially equal to actual steering angle .theta. detected by steering
 angle sensor 54, and control halt mode RM in which a higher priority is
 taken over the vehicular manipulation with the control in steering control
 mode FM halted under the predetermined transition conditions.
 That is to say, if main switch SW.sub.M is turned on from its turn-off
 state, steering controller 50 enters from a steering stop state (not shown
 in FIG. 19) into control wait mode WM. In control wait mode WM, when such
 an 11-th (eleventh) condition is established that set switch SW.sub.S is
 turned on under the state where, in control wait mode WM, the vehicle is
 running at vehicular velocity V equal to or lower than a predetermined
 velocity value of Vk and the white line is detected by white line detector
 51.
 If, in control halt mode RM, such a 12-th (twelfth) condition is
 established that the vehicle is running at vehicular velocity V equal to
 or lower than predetermined velocity value Vk, the white line not detected
 by means of white line detector 51, and set switch SW.sub.S becomes on
 state, steering controller 50 transfers its mode to control halt mode RM.
 When, in steering control mode FM, such a 13-th (thirteenth) condition is
 established that white line detector 51 cannot detect the white line any
 more, there is an intervention of the vehicular driver's steering
 operation, or a winker is operated, the mode transition from steering
 control mode FM to control halt mode RM occurs as shown in FIG. 19.
 When, in the steering control mode, such a 14-th (fourteenth) condition is
 established that cancel switch SW.sub.C is turned on or vehicular velocity
 V exceeds predetermined velocity value of Vk is established, the mode
 transition from steering control mode FM to control wait mode WM occurs.
 Furthermore, when, in control halt mode RM, such a 15-th (fifteenth)
 condition is established that white line detector 51 can detect the white
 line and the intervention of the vehicular driver's steering operation and
 the winker operation is ended or becomes eliminated, the mode transition
 from control halt mode RM to steering control mode FM occurs.
 When, in control halt mode RM, such a 16-th (sixteenth) condition that
 cancel switch SW.sub.C is turned on or that vehicular velocity V exceeds
 the predetermined velocity value is established, the mode transition from
 control halt mode RM to control wait mode WM occurs.
 Then, steering controller 50 executes a steering control procedures as
 shown in FIGS. 20 through 23.
 FIG. 20 shows the steering control selection procedure in the third
 embodiment (FIG. 20 shows the main routine in the case of the third
 embodiment).
 At a step S201, controller 50 determines if the present mode is in control
 wait mode WM. If Yes at step S201, the routine goes to a step S202 in
 which the transition destination selection procedure is executed as shown
 in FIG. 21.
 If No at step S201, the routine goes to a step 202 in which the transition
 destination selection procedure is executed as shown in FIG. 21.
 If No at step S201, the routine goes to a step S203.
 At step S203, controller 50 determines if the present mode is in a steering
 control mode FM.
 If Yes at step S203, the routine goes to a step S204.
 At step S204, the transition destination selection procedure from steering
 control mode FM shown in FIG. 22 is executed.
 If No at step S203, the routine goes to a step S205.
 At step S205, the transition destination selection procedure from control
 halt mode RM shown in FIG. 23 is executed.
 Then, controller 50 determines if the present mode is in the control wait
 mode at a step S206.
 If yes at step S206, the routine goes to a step S207 in which the control
 wait mode processing WM is executed.
 If No at step S206, the routine goes to a step S208.
 At step S208, controller 50 executes the steering control.
 In details, controller 50 calculates target steering angle .theta.s* from
 lateral deviation Y1 received from white line detector 51 and vehicular
 velocity V detected by vehicular velocity sensor 52 and executes the
 steering control such that electric motor 56 is controlled to make actual
 steering angle .theta. detected by steering angle sensor 54 substantially
 equal to target steering angle .theta.s* and the routine is ended.
 If not in steering control mode FM (No) at step S208, the routine goes to a
 step S210.
 At step S210, control halt mode RM is executed.
 It is noted that except steering control mode FM, the contents of steps
 S201 through S210 generally correspond to step S1 through S10 shown in
 FIG. 3.
 FIG. 21 shows the transition destination selection procedure from the
 control wait mode at step S202 in FIG. 20.
 At step S131, controller 50 determines if set switch SW.sub.S is turned on.
 If set switch SW.sub.S is turned on (Yes), the routine goes to step S133.
 If set switch SW.sub.S is turned off (No) at step S133, the routine goes
 to a step S132.
 At step S132, control wait mode WM is maintained.
 At step S133, controller 50 determines if vehicular velocity V is equal to
 or lower than predetermined velocity value Vk. It is noted that the value
 of Vk corresponds to upper limit value V.sub.H described in the first
 embodiment.
 If V.ltoreq.Vk at step S133 (Yes), the routine goes to a step S134.
 If V&gt;Vk (No) at step S133, the routine goes to a step S132.
 At step S134, controller 50 determines if white line detector 51 detects
 the white line.
 If the white line is detected (Yes) at step S134, the routine goes to a
 step S135.
 If No at step S134, the routine goes to a step S136.
 At step S136, the present mode is changed to control halt mode RM.
 At step S135, the present mode is changed to steering control mode FM.
 After each of steps S132, S135, and S136, the routine is ended.
 It is noted that the phrase that white line detector 51 cannot be detect
 the white line any more does not have the meaning that white line detector
 51 cannot detect the white line due to its failure (physical trouble).
 FIG. 22 shows the transition destination selection procedure from the
 steering control mode at step S204 shown in FIG. 20.
 At step S141, controller 50 determines if cancel switch SW.sub.C is turned
 on. If cancel switch SW.sub.C is turned on (Yes) at step S141, the routine
 goes to a step S142.
 If cancel switch SW.sub.C is turned off (No) at step S141, the routine goes
 to a step S143.
 At step S142, controller 50 changes the present control mode to control
 wait mode WM and the present routine is ended.
 At step S143, controller 50 determines if vehicular velocity V is equal to
 or lower than predetermined velocity value Vk. If V&gt;Vk (No) at step
 S143, the routine goes to a step S144. If V.gtoreq.Vk (Yes) at step S143,
 the routine goes to step S145.
 At step S144, controller 50 outputs alarm signal AS having the logical
 value of "1" to produce the alarm sound and the routine goes to step S142.
 At step S145, controller 50 determines whether a winker manipulation is
 carried out. If the winker manipulation is carried out, the routine goes
 to step S146. With the present control mode maintained at control halt
 mode RM, the routine is ended. If no winker is manipulated (No) at step
 S145, the routine goes to a step S147.
 At step S147, controller 50 determines whether the intervention of the
 vehicular driver's manipulation to steer the vehicle through the steering
 wheel is carried out. If carried out (Yes) at step S147, the routine goes
 to a step S146.
 If not carried out (No) at step S145, the routine goes to a step S147.
 At step S148, controller 50 determines whether a white line image has been
 lost. If the white line image is lost (Yes) at step S148, the routine goes
 to a step S150. At step S150, controller 50 outputs alarm signal AS having
 the logical value of "1" to alarm unit 56 to produce the alarm sound and
 the routine goes to a step S146.
 Furthermore, FIG. 23 shows the detailed procedure in the transition
 destination selection procedure from control halt mode RM at step S205
 shown in FIG. 20.
 The series of processes from step S151 to step S157 carry out the same
 processing as steps S141 through S147 in the transition destination
 selection procedure from steering control mode FM in FIG. 22.
 However, at a step S158, controller 50 determines whether white line
 detector 51 is received from a state in which the white line image is lost
 to its normal state.
 If not received to its normal state (No) at step S158, the routine goes to
 a step S156 in which control halt mode RM is maintained.
 If recovered to its normal state (Yes) at step S158, the routine goes to a
 step S159.
 At step S159, controller 50 outputs alarm signal AS having the logical
 value of "1" to alarm unit 56 to produce the alarm sound. Then, the
 routine goes to a step S160 in which the present control mode is changed
 to steering control mode FM and the routine is ended.
 According to the third embodiment, even in the automatic steering control
 apparatus, the occurrence of the mode transition such that the recognition
 of the mode transition by the vehicular driver tends to be insufficient is
 informed to the vehicular driver in the same way as the vehicular
 following controlling apparatus in the first embodiment. For example, the
 occurrence of such the mode transition to control halt mode RM due to the
 loss of the white line image or the resume of the steering control mode
 due to the recovery of the white line image is the transition such that
 the vehicular driver is difficult to be noticed due to the fact that the
 torque developed by the electric motor is not acted upon the steering even
 during the control in a case where the vehicle is running on a straight
 road.
 In this situation, the steering controlling apparatus can positively inform
 the vehicular driver of the occurrence of the mode transition described
 above.
 In addition, when the mode transition occurs from steering control mode FM
 to control wait mode WM due to the fact that the vehicular velocity is
 increased and exceeded the upper limit vehicular velocity within which the
 controllable range is set, the information that control wait mode WM is
 not changed to steering control mode FM unless the vehicular driver turns
 on set switch SWS can positively be recognized by the vehicular driver.
 In addition, convenience in usage can be improved. Furthermore,
 irrespective of already uncontrollable state, such a mistake by the
 vehicular driver that the control mode must be steering control mode FM
 and an excessive expectation that the steering control would be carried
 out can be prevented from occurring.
 It is noted that, in each of the first, second, and third embodiments, the
 alarm sound is produced when the mode transition recognition by the
 vehicular driver tends to be insufficient.
 However, the occurrence of such a mode transition as is difficult to be
 recognized by the vehicular driver may be informed to the vehicular driver
 through a display device constituted by a liquid crystal panel or a light
 emitting diode.
 Hence, an informing device defined in the claims corresponds to the alarm
 unit described in each of the embodiments or the display device described
 above.
 It is also noted that, in each of the first, second, and third embodiment,
 the same alarm sound is produced when such a mode transition that the
 recognition by the vehicular driver tends to be insufficient occurs.
 However, according to kinds of the mode transitions, timbre (tone color),
 a pitch of sound, or a sound duration of time may be set so that the alarm
 sound can cause an identification of the kinds of mode transition to be
 recognized by the vehicular driver.
 The entire contents of a Japanese Patent Application No. Heisei 11-186498
 (filed in Japan on Jun. 30, 1999) are herein incorporated by reference.
 Although the invention has been described above by reference to certain
 embodiment of the invention, the invention is not limited to the
 embodiments described above. Modifications and variations of the
 embodiments described above will occur to those skilled in the art in the
 light of the above teachings. The scope of the invention is defined with
 reference to the following claims.