JP3547149B2 - Throttle valve opening control system for small automatic driving vehicles - Google Patents

Description

[0001]
[Industrial applications]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve opening control device for an automatic traveling vehicle that controls a vehicle speed to be equal to a set vehicle speed by opening and closing a throttle valve by a motor.
[0002]
[Prior art]
In golf cars and unmanned transport vehicles in factories, it is possible to detect guidance lines embedded along the traveling course with sensors such as induction coils provided on the vehicle body and to enable unmanned traveling while automatically controlling the vehicle speed to the set vehicle speed. A known vehicle, that is, a small automatic traveling vehicle, is known. For example, a coil (induction coil) for detecting an AC magnetic field formed by the AC current is provided on the vehicle side while an AC current is supplied to the induction line, and a deviation from the induction line of the vehicle due to a change in the detection output of the coil. That is, there is an apparatus that detects a deviation amount and steers the steered wheels of the vehicle such that the deviation amount falls within a predetermined range. In this type of small vehicle, an electric motor is often used as a driving power source to simplify vehicle speed control.
[0003]
[Problems of the prior art]
However, in this case, there are problems such as an insufficient traveling distance per charge, an increase in the weight of the motor and the battery, and damage to the lawn. Therefore, it is conceivable to use a gasoline engine as a driving power source instead of the motor. In this case, it is necessary to control the vehicle speed by opening and closing the throttle valve.
[0004]
However, since there is a time delay between the opening and closing of the throttle valve and the change in the vehicle speed, when the load increases suddenly at the time of starting or climbing a steep hill, an increase in the engine output may not be able to follow this sudden increase in the load. For this reason, there has been a problem that the vehicle speed decreases, speed control becomes unstable, and the engine may stop.
[0005]
[Object of the invention]
The present invention has been made in view of such circumstances, and when an engine is used as a driving power source, the output of the engine is rapidly increased even if the load is suddenly increased, the vehicle speed is quickly stabilized, and the vehicle speed is accurately controlled. It is an object of the present invention to provide a throttle valve opening control device for a small-sized automatic traveling vehicle that can be well controlled.
[0006]
Configuration of the Invention
According to the present invention, the object is to transmit the rotational output of the engine to the drive wheels via a V-belt type automatic transmission, and to control the throttle valve opening by a motor to thereby set the current vehicle speed (V) to the set vehicle speed (V). V ₀ ), a throttle valve control means for normal running that controls the throttle opening (θ) to the reference instruction opening (θ _s ), and a set vehicle speed (V _0). ) And the current vehicle speed (V) , a subtraction unit for obtaining a vehicle speed difference (ΔV = V ₀ −V ), a speed ratio calculation unit for obtaining a speed ratio (K) of the automatic transmission, and a vehicle speed obtained by the subtraction unit The difference (ΔV) is larger than the set vehicle speed difference (ΔV ₀ ) and / or the speed ratio (K) obtained by the speed ratio calculator is larger than the set speed ratio (K ₀ ) . Since the condition is met, a sudden increase in load is detected and the slot Throttle control means for controlling the throttle opening (θ) to an instruction opening (θ _sa ) greater than the reference instruction opening (θ _s ) by the valve control means. This is achieved by an opening control device.
[0007]
【Example】
FIG. 1 is a conceptual diagram of an engine-driven golf car used for explaining one embodiment of the present invention, FIG. 2 is a conceptual diagram of a vehicle speed control system thereof, FIG. 3 is a block diagram thereof, and FIG. FIG. 5 is a characteristic diagram, and FIG. 5 is a control characteristic diagram at the time of climbing. This golf car is capable of switching between an unmanned traveling mode in which unmanned guidance is performed and a manual traveling mode in which a driver rides and operates manually.
[0008]
In FIG. 1, reference numeral 10 denotes a vehicle body of a golf car as an automatic traveling vehicle according to the present invention. At the front of the vehicle body 10, front wheels 12, 12 as steering wheels are arranged, and at the rear, rear wheels 14, 14 as driving wheels are arranged. In addition, a step 16 is provided at the rearmost portion of the vehicle body 10 so that the driver can get on the vehicle during manual operation.
[0009]
Reference numeral 18 denotes a luggage mounting carrier fixed to a front portion of the vehicle body 10, and a golf bag is placed on the carrier 18.
[0010]
A steering shaft 20 extending obliquely upward toward the rear of the vehicle body is rotatably held at the center of the vehicle body 10 in the vehicle width direction. A steering handle 22 is attached to an upper end of the steering shaft 20. An accelerator lever 24 is attached to the right end of the handle 22, and a brake lever 26 is attached to the left end. These are used in a manual traveling mode where a person rides and steers manually.
[0011]
A steering arm 28 is fixed to a lower end of the steering shaft 20. The turning end of the steering arm 28 is connected to the knuckle arms 32 of the left and right front wheels 12 via the steering rods 30.
[0012]
Reference numeral 36 denotes an electric motor for automatic steering that operates in the unmanned traveling mode, and is fixed to the vehicle body 10 side. The rotation of the motor 36 is transmitted to the steering shaft 20 by a chain 38 (or a toothed belt). A pair of left and right guide line sensors 40 are provided below the carrier 18 to detect a guide line 42 laid on a road surface along a traveling route. Since the output of each sensor 40, 40 changes in accordance with the distance from the guide line 42, it is possible to determine the deviation of the vehicle body 10 from the guide line 40, that is, the guide deviation based on the difference between the outputs of the two sensors 40, 40. it can.
[0013]
The sensors 40, 40 may swing right and left within a predetermined angle range in synchronization with the rotation of the steering shaft 20. In this case, the direction deviation of the vehicle body 10 due to the steering of the front wheels 12 is predicted to determine the guidance deviation, and the steering accuracy by the unmanned guidance can be improved. The outputs of the sensors 40 and 40 also change depending on the inclination of the road surface or the vehicle body 10 in the left-right direction. Therefore, in order to prevent a decrease in accuracy due to this output change, three sensors 40 may be arranged at equal intervals to compare the outputs of the three sensors 40 to determine the induced deviation.
[0014]
The golf car 10 can select between an unmanned traveling automatic mode and a manual mode in which it is steered by the steering wheel 22. In the automatic mode, the motor 36 is controlled by a steering control device (not shown). That is, based on a steering angle command from another main controller, the motor 36 is rotated right or left by a predetermined rotation amount.
[0015]
Next, the power system will be described. Reference numeral 50 denotes an engine mounted near the center of the vehicle body 10, and 52 denotes a drive case disposed between the rear wheels 14, 14. The rotation of the crankshaft of the engine 50 is transmitted to the input shaft of the drive case 52 via a V-belt type automatic transmission 54. An electromagnetic brake 56 (FIG. 2) is interposed between the transmission 54 and the input shaft of the transmission case 52. The electromagnetic brake 56 is preferably a spring-closed type which is excited when the vehicle is running and the brake is released, and is de-energized and the brake is applied when the main power is turned off.
[0016]
The drive case 52 is provided with a disk brake 58 for restricting rotation of an input shaft and a shaft (not shown) interlocking with the axle of the rear wheel 14. The brake 58 is manually operated by the brake lever 26 of the handle 22. Therefore, the output of the engine 50 is transmitted to the input shaft of the drive case 52 via the transmission 54, and is transmitted to the rear wheel 14 via the reduction gear and a differential device (both not shown) in the drive case 52. . A mechanical governor 64 is mounted in the transmission case 52 of the engine 50, and controls the opening of the throttle valve 62 of the carburetor 60 so as to limit the traveling speed in the manual mode.
[0017]
The throttle valve 62 of the carburetor 60 connected to the engine 50 is opened and closed by the accelerator lever 24 via a switching device 65 and a governor 64, and by a step motor 68 via a switching device 65 and an electromagnetic clutch 66. That is, in the manual mode, the electromagnetic clutch 66 is disengaged and the rotation of the accelerator lever 24 is transmitted to the throttle valve 62 via the governor 64 and the switching device 65. In the automatic mode, the electromagnetic clutch 66 is engaged, and the throttle valve 62 is opened and closed by the rotation of the step motor 68. At this time, the opening degree (current opening degree) θ of the throttle valve 62 is detected by the throttle sensor 70 and is fed back to the throttle valve opening degree control device 72, and this opening degree (current opening degree θ) is an instruction opening degree (described later). θ _s ).
[0018]
Next, the throttle valve opening control device 72 for controlling the throttle valve opening to set the vehicle speed to the set vehicle speed in the unmanned traveling mode will be described. The device 72 includes a microcomputer (CPU) 74, and the output of the throttle sensor 70 is input via an input interface (not shown). The throttle sensor 70 is constituted by, for example, a potentiometer whose output voltage changes according to the rotation angle, and its output is digitized by an interface and input to the CPU 74. The CPU 74 has various calculation functions constituted by software, and obtains the current opening degree θ of the throttle valve by calculation.
[0019]
The vehicle speed V is also input to the CPU 74. For example, a vehicle speed sensor 76 that outputs a pulse in synchronization with the rotation of the rear wheel 14 is attached to the drive case 52, and the output of the sensor 76 is input to the CPU 74 via an interface (not shown). The CPU 74 calculates the current vehicle speed V by counting the output pulses of the sensor 76.
[0020]
Furthermore the set speed V _o is the CPU74 are inputted via the interface (not shown). The set vehicle speed V _o are those set by the other control device based on the travel pattern of the automatic driving mode. In CPU74 These set speed V _o, the instruction opening theta _s computed by the throttle valve control means 78 for normal running with the current vehicle speed V and the current opening theta.
[0021]
Throttle valve control means for the normal running 78 is for calculating an indication opening of the throttle valve (referred to this time indication opening theta _s reference designating opening of) during travel in the normal load. Here? Load is increasing rapidly or the normal range, the vehicle speed difference ΔV between the current vehicle speed V and set vehicle speed V _o a (= V _o -V) determined in the subtraction portion 80 is set to the vehicle speed difference ΔV from the outside It is determined by comparing the set vehicle speed difference ΔV _o with the comparing unit 82.
[0022]
That is, the comparison unit 82 determines that the load is in the normal load change range when ΔV <ΔV ₀ , and obtains the throttle instruction opening (reference instruction opening) θ _s during normal running in the throttle opening calculation unit 84. It is. This calculation is performed according to a predetermined equation.
θ _s = f (V _s )
Ask for. Can be used primary function f (V _s) as V _s function _{f (V s) = k 1} V s 2 + k 2. Here, V _s is the vehicle speed, and k ₁ and k ₂ are positive constants.
[0023]
When ΔV ≧ ΔV ₀ , the comparing section 82 determines that the load has increased rapidly. For example, it is determined that the vehicle has suddenly started or entered a steep slope. At this time, the correction instruction section 86 of the CPU 74 sends a correction instruction signal a for the throttle valve opening to the throttle opening calculation section 84. According to the present invention, at least one of the conditions that the vehicle speed difference ΔV is larger than the set vehicle speed difference ΔV ₀ and that the speed ratio K of the transmission 54 is detected and becomes equal to or more than the set value K ₀ is satisfied. and it detects the sudden increase in load since the meet, but here is described the case of detecting a sudden increase of the load using the vehicle speed difference [Delta] V.
[0024]
When receiving the correction instruction signal a, the arithmetic section 84 outputs an instruction opening degree θ _sa larger than the throttle reference instruction opening degree θ _s during the normal running. For example arithmetic unit 84 receives the correction instruction signal a, by adding a constant correction amount [Delta] [theta] _s to the reference instruction opening theta _s,
θ _sa = θ _s + Δθ _s
And The larger fixed angle reference indication opening theta _s may theta _sa. In Figure 3 88 shows the increase correcting means for obtaining the detected and reference instruction opening theta _s larger instruction opening theta _sa a rapid increase of the load.
[0025]
The indicated opening degree θ _s or θ _sa thus obtained is input to the output unit 90 via an output interface (not shown). The output unit 90 is currently opening theta throttle valve 62 controls the stepping motor 68 so that the instruction opening theta _s or theta _sa. The above operation is repeated until a stop signal is input.
[0026]
Next, the operation at the time of starting will be described with reference to FIG. First, starting in time t _o, and press the switch, CPU74 is to start the engine, after confirming the ignition of the engine, to automatically start at time t _1. The period from t _{o to} t ₁ is a period for confirming the start of the engine, the set vehicle speed V _o becomes 0, and the throttle opening calculating section 84 outputs the idling opening θ _so as the instruction opening θ _s .
[0027]
At time t ₁ when the CPU74 increase the set vehicle speed V _0, for example, in 10 km / h. Then, since the vehicle speed difference ΔV becomes larger than the set vehicle speed difference ΔV ₀ , the increase correction means 88 outputs a correction instruction signal a. For this reason, the throttle opening calculating section 84 outputs, for example, a fixed command opening θ _sa (where θ _sa is larger than the reference command opening θ _s at this time) .
[0028]
Therefore, since the throttle opening θ is controlled to the command opening _θsa , the engine output increases rapidly and the vehicle speed V also increases rapidly. When it goes [Delta] V = [Delta] V _o at time t _2, the correction instruction signal a is no longer, the throttle opening is controlled to stop the increase correction by the reference instruction opening theta _s.
[0029]
FIG. 5 shows the operation when the load suddenly increases while approaching a steep hill while traveling on a flat road. The vehicle speed V decreases rapidly enters the steep slope at time t _3. Speed difference [Delta] V is between times t ₄ when becomes [Delta] V _o is the throttle valve opening is controlled to the reference instruction opening theta _s by normal running. [Delta] V = [Delta] V _o to an increase correction signal a is output and opening control to the instruction opening theta _sa. And ΔV <ΔV _o too much time t ₅ which is to again increase correction signal a return to the normal running disappear. That is controlled to the reference instruction opening theta _s.
[0030]
In the above embodiment , the increase correction means 88 determines whether or not to perform the opening degree increase correction by comparing the vehicle speed difference ΔV between the vehicle speed V and the set vehicle speed V ₀ with the set vehicle speed difference ΔV ₀ . . However, this invention is intended to detect a sudden increase of the load using the gear ratio K with the vehicle speed difference [Delta] V, along with the vehicle speed difference [Delta] V and the gear ratio K, the vehicle speed difference [Delta] V, deceleration D, the gear ratio of the change rate [Delta] K, engine The sudden increase in the load may be determined using the speed N and the increase rate ΔN of the engine rotation speed together.
[0031]
FIG. 6 is a diagram showing a configuration example of the increase correction means 88A in the case of determining a sudden load increase based on the gear ratio K. In this figure, reference numeral 92 denotes a gear ratio calculation unit, which calculates the gear ratio K of the automatic transmission 54 using the current vehicle speed V and the engine rotation speed N.
[0032]
That is, in the automatic transmission 54, the speed ratio K automatically increases when the load suddenly increases, so that a sudden increase in the load can be detected from the speed ratio K. The determined transmission ratio K are compared by comparator 94 with the set speed ratio K _o, the correction instruction unit 96 when K ≧ K _o is intended to increase correct instruction opening theta _s outputs a correction instruction signal a is there.
[0033]
FIG. 7 is a diagram showing an example of the configuration of the correction means 88B for determining a sudden increase in the load based on the deceleration D, particularly when climbing a steep slope. In this figure, reference numeral 98 denotes a deceleration calculating unit which obtains the deceleration D from the time change ΔV of the current vehicle speed V. The deceleration D are compared by comparator 100 with the set deceleration D _o, it is determined to have entered the steep slope when D ≧ D _o. At this time, the correction instruction unit 102 outputs a correction instruction signal a.
[0034]
FIG. 8 is an operation flowchart of another embodiment. In this embodiment, the vehicle speed difference ΔV, the gear ratio K, the deceleration D and the engine speed N shown in FIGS. That is, when the vehicle speed control is started (step 200), first, the vehicle speed difference ΔV and the deceleration D are calculated (step 202), and further the engine speed N is obtained (step 204), and then the gear ratio K is calculated (step 206). .
[0035]
The vehicle speed difference [Delta] V is compared with the set vehicle speed difference [Delta] V _o (step 208), and outputs a correction instruction signal a if ΔV ≧ ΔV _o (step 210). Similarly _{D ≧ D o, K ≧ K} o, and outputs the N ≧ N _o If the correction instruction signal a (step 212, 214, 216). Here N _o is set engine rotational speed.
[0036]
That is, when any one of the conditions of steps 208, 212, 214, and 216 is satisfied, the correction instruction signal a is output. And controlling the throttle opening theta large instruction opening theta _sa than the reference instruction opening theta _s when the corresponding instructions opening theta _sa normal traveling (step 218).
[0037]
Also if the condition of step 208,212,214,216 is satisfied none is controlled from the correction instruction signal a is not output to the reference instruction opening theta _s for normal running (step 218). As described above, when the load suddenly increases, the throttle opening θ is opened to an opening θ _sa that is larger than the reference instruction opening θ _s during normal driving, so that the engine output increases rapidly, and the vehicle speed suddenly decreases or the vehicle speed control. Will not become unstable.
[0038]
【The invention's effect】
As described above, according to the present invention , the vehicle speed difference (ΔV = V ₀ −V) between the set vehicle speed (V ₀ ) and the current vehicle speed (V) sharply increases, and the speed ratio K of the automatic transmission sharply increases. Since it is provided with an increase correction means for determining a sudden increase in the load from satisfying at least one of the conditions and opening the throttle valve opening to an opening θ _sa larger than the reference instruction opening θ _s in normal traveling, The set vehicle speed difference ΔV ₀ and the set speed ratio K ₀ can be set separately, and the degree of freedom in design increases. By setting these separately appropriately for this purpose can be stabilized promptly set vehicle speed V ₀ rapidly engine output increases vehicle speed when approaching the starting or steep.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of an engine-driven golf car for explaining an embodiment of the present invention. FIG. 2 is a conceptual diagram of a vehicle speed control system. FIG. 3 is a block diagram thereof. FIG. FIG. 5 is a control characteristic diagram when climbing a hill. FIG. 6 is a diagram showing another embodiment of the increase correction means. FIG. 7 is a diagram showing another embodiment of the increase correction means. Operation flow chart [Explanation of reference numerals]
72 Throttle valve opening control device 74 CPU
78 Throttle valve control means 88, 88A, 88B Increase correction means θ _s Reference command opening θ _sa Command opening corrected by increase

Claims (1)

By transmitting the rotation output of the engine to the driving wheels via a V-belt type automatic transmission and controlling the throttle valve opening by a motor, the speed is adjusted so that the current vehicle speed (V) matches the set vehicle speed (V ₀ ). In a controlled small autonomous vehicle, a throttle valve control means for normal running for controlling the throttle opening (θ) to a reference instruction opening (θ _s ), and a control of a set vehicle speed (V ₀ ) and a current vehicle speed (V). A subtraction unit for calculating the vehicle speed difference (ΔV = V ₀ −V), a speed ratio calculation unit for calculating the speed ratio (K) of the automatic transmission, and a vehicle speed difference (ΔV) determined by the subtraction unit are set vehicle speed differences ( ΔV ₀ ), and the speed ratio (K) obtained by the speed ratio calculation unit satisfies at least one of the conditions of the set speed ratio (K ₀ ). Detected and reference indication by the throttle valve control means A throttle valve opening control device for a small automatic traveling vehicle, comprising: an increase correction means for controlling a throttle opening (θ) at an instruction opening (θ _sa ) larger than the opening (θ _s ).

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