JPH08272441A - Radio control system for vehicle - Google Patents

Abstract

PURPOSE: To reduce failure of a steering control system due to an unreasonable operation after contact with an obstruction by reducing a load on a steering means when such a state that the load on the steering means exceeds a prescribed value is continued for prescribed time. CONSTITUTION: When the front wheel of a vehicle comes in to contact with the obstruction such as a stone, etc., a steering operation is blocked, which generates unmatching between a target steering position and an actual steering position, therefore, the steering control system increases the duty factor of a steering motor rotating speed signal to be outputted to a motor drive circuit 22 so as to increase a steering motor driving current by trying to match their positions with each other. When such motor current arrives at a prescribed value (overcurrent detection level) or over, an overcurrent sensor 8b outputs an overcurrent detection signal, and when such state is continued for abnormal current judging time, it is judged that the front wheel comes into contact with the obstruction such as the stone, etc., and the duty factor of the motor rotating speed signal is reduced so as to decrease the motor current to exclude the fault of the steering control system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for remotely controlling a vehicle using radio waves, and more particularly to a technique for preventing a failure of a steering control system of a vehicle and improving safety.

[0002]

2. Description of the Related Art Many types of vehicles are used in a factory yard, depending on the application and process, such as semi-finished product transportation, product transportation to a distribution base, or waste transportation. In recent years, it has been known that a vehicle for wirelessly controlled premises has been developed for the purpose of productivity improvement and work improvement due to labor saving (Pre-prints of Academic Lecture Meeting of the Society of Automotive Engineers 944 1994-).
10).

A radio control device (hereinafter, referred to as a transmitter) used in the operation of the radio control type private vehicle (hereinafter, referred to as a radio control vehicle) includes a steering control volume, a transmission position select during traveling, and a transmission position selection. A joystick for controlling the vehicle speed and controlling the engine rotation during cargo handling work, and a switch group for cargo handling operations are installed. By these operations, the signal from the transmitter is transmitted by radio waves and is controlled by the vehicle-mounted device.

[0004]

By the way, in the vehicle radio control system, since the radio control vehicle is remotely operated outside the vehicle by using a transmitter, for example, the front wheel of the vehicle comes into contact with a curb or the like and steering is impossible. Even then, the state cannot be recognized immediately, and an overload may be applied to the operating means by an unreasonable operation, which may cause a failure of the steering control system.

In view of the above problems, the present invention prevents the operating means from being overloaded when the front wheels of the vehicle come into contact with an obstacle such as a curb,
It is intended to prevent the failure of the steering control system and improve the safety.

[0006]

Therefore, according to the invention described in claim 1, in a system for remotely controlling a vehicle by radio, a wireless control vehicle controlled by a wireless control device for controlling the vehicle by radio controls the vehicle. Steering means for operating,
Overload detection means for detecting that the load of the steering means of the vehicle has exceeded a predetermined value, and overload determination for judging that the steering means is overloaded when the signal from the overload detection means continues for a predetermined time or longer. Means, and steering control means for controlling the steering means and for reducing the load on the steering means when it is determined that an overload has occurred.

According to a second aspect of the present invention, the radio-controlled vehicle reduces the load on the emergency stop means for stopping the vehicle and the steering means, but the overload judging means further causes an overload. When it is determined that the steering means is a failure, a failure determination means and an emergency stop control means that controls the vehicle by the emergency stop means when a failure is determined are included. .

[0008]

According to the first aspect of the present invention, during steering of the vehicle, for example, when the front wheels come into contact with an obstacle such as a curb, etc., the load of the steering means is prevented in order to prevent the operation means from being overloaded. Therefore, it is possible to reduce the failure of the steering control system due to the unreasonable operation after the contact.

According to the second aspect of the present invention, even though the load reducing control of the steering means is performed, the failure of the steering means is detected by continuing the overload state, and the vehicle is brought to an emergency stop. Therefore, traveling in a state where steering is impossible is eliminated, and safety in traveling the vehicle can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows the overall system configuration of an embodiment of the present invention. The radio-controlled vehicle system is roughly classified into a radio-controlled device (hereinafter, referred to as a transmitter) 1 that gives a command to operate the vehicle by an operation of a driver, and a radio-controlled vehicle 6 that runs based on a command from the transmitter 1. And a control command from the transmitter 1 to the vehicle-mounted control device (hereinafter, referred to as a receiver) 7 that controls the radio-controlled vehicle 6 by using two waves in the VHF band having different frequencies. Bidirectional communication is performed with vehicle monitor information from the receiver 7 to the transmitter 1.

The vehicle is equipped with an engine (not shown) as a driving prime mover. In addition, the transmitter 1 includes a steering control volume (hereinafter referred to as volume) 2 for steering the vehicle, a joystick for transmission position selection and vehicle speed control during traveling, and an engine rotation control instruction during cargo handling work. (Hereinafter, referred to as a joystick) 3, a liquid crystal display monitor (hereinafter, referred to as a liquid crystal display monitor) 4 that displays a control state of the wirelessly controlled vehicle 6, an antenna 5a that issues a control command of the vehicle, and a cargo handling operation. Switch group (not shown).

On the other hand, the radio-controlled vehicle 6 receives the vehicle control command from the transmitter 1 through the antenna 5b and the receiver 7
And a steering motor 8 for steering operation according to a steering control command, and an accelerator controller 9 for controlling engine rotation based on an engine rotation control instruction.
And a brake pressure controller 10 that performs brake control based on a brake control command, and a T / M controller 11 that performs T / M control based on a transmission (hereinafter referred to as T / M) control command. . In addition to the above configuration, the sensors for detecting the control state of the vehicle include a steering position sensor 8a for detecting the steering operation state and an overcurrent signal when a driving current of the steering motor 8 is detected and a current of a predetermined value or more flows. And an overcurrent sensor 8b for outputting the engine speed and a rotation sensor 9a for detecting the engine speed.
And a vehicle speed sensor 9b for detecting the vehicle speed of the radio-controlled vehicle 6.
And a brake pressure sensor 10a for detecting the brake pressure,
A position sensor 11a for detecting the T / M gear position,
Is attached.

FIG. 2 shows a block diagram of a control system of the transmitter 1 and the receiver 7. The transmitter 1 is a transmitter control device (abbreviated as CPU in the drawing) 14 that controls the transmitter 1.
A wireless unit 16a that performs wireless transmission and reception, and a wireless / wired switching circuit (hereinafter referred to as a switching circuit) 15a that switches to wired control to enable wired control when the wireless unit 16a malfunctions or the radio wave environment deteriorates. It is composed of various switches and a nickel hydrogen battery (hereinafter referred to as a battery) 17 that supplies power to each element of the transmitter 1.

Volume 2, joystick 3, mode selector switch 1 for switching between vehicle running and cargo handling work
2 and the output of the emergency stop switch 13 for performing an emergency stop of the vehicle are input to the transmitter control device 14 and the switching circuit 15a.
And is transmitted from the antenna 5a via the wireless unit 16a. On the other hand, the radio-controlled vehicle 6 sent from the vehicle side
The content of the vehicle monitor information is displayed on the liquid crystal display monitor 4 by the transmitter control device 14. Further, the voltage of the battery 17 is input to the transmitter control device 14 via an A / D converter (not shown), and the voltage is monitored.

On the other hand, the receiver 7 is a vehicle control device (abbreviated as CPU in the drawing) 1 for controlling the receiver 7 and the vehicle 1.
8, a switching circuit 15b, and a wireless unit 16b that performs wireless transmission / reception. The vehicle control device 1
Reference numeral 8 has the functions of the overload determination means and the steering control means according to claim 1 or the failure determination means and the emergency stop control means according to claim 2.

The vehicle control command sent from the transmitter 1 is transmitted to the antenna 5b, the radio unit 16b and the switching circuit 1.
It is input to the vehicle control device 18 via 5b. And
The vehicle control command is issued from the vehicle control device 18 by a steering motor 8 as steering means for steering the vehicle, an accelerator controller 9 for engine rotation control, and a brake pressure controller 10 as emergency stop means for brake control. And a T / M controller 11 that performs T / M control, and a PTO that controls various cargo handling operations.
(Power Take Off) control 19 and the output. Further, each of a steer position sensor 8a as various sensors for detecting the control state of the vehicle, an overcurrent sensor 8b as overload detection means, a rotation sensor 9a, a vehicle speed sensor 9b, a brake pressure sensor 10a and a position sensor 11a. The output is input to the vehicle control device 18, and the output contents of the steer position sensor 8a, the rotation sensor 9a, and the position sensor 11a are sent to the transmitter 1.

In addition to the above, the radio-controlled vehicle 6 has
When a vehicle control abnormality occurs, an alarm display 20 for displaying the content thereof is provided, and the vehicle control device 18
The display is controlled by. Furthermore, the wireless unit 16
A wired cable 21 is also provided for performing wired control between the transmitter and the receiver so that wired control can be performed when a and 16b are broken or the radio wave environment deteriorates.

FIG. 3 shows a block diagram of the steering control system according to the present invention. A vehicle control device (abbreviated as CPU in the drawing) 18 in the wirelessly controlled vehicle sends a signal for driving the steering motor 8 to a motor drive circuit 22 based on a steering control command as a target steering position sent from the transmitter 1. Output to. This signal is composed of a forward rotation signal, a reverse rotation signal and a rotation speed signal which also serve as an operation / stop signal of the steering motor 8.

Then, the motor drive circuit 22 drives the steering motor 8 for driving the steering column based on the drive signal from the vehicle control device 18 to perform the steering operation of the vehicle. On the other hand, the steering position sensor 8a provided on the steering column detects the actual steering position and outputs it to the vehicle control device 18. Upon receiving this signal, the vehicle control device 18 adjusts the drive signal output to the motor drive circuit 22 based on the target steering position and the actual steering position sent from the transmitter 1. The overcurrent sensor 8b provided in the motor drive circuit 22 detects the drive current of the steering motor 8 and outputs an overcurrent signal to the vehicle control device 18 when a current of a predetermined value or more flows.

FIG. 4 is a time chart showing the outline of steering control according to the present invention, in which the motor rotation speed signal with respect to time,
It represents changes in the motor current, the forward rotation switching signal, the reverse rotation switching signal, and the overcurrent detection signal. When the front wheels of the vehicle come into contact with an obstacle such as a curb, steering operation is hindered, and the target steering position and the actual steering position do not match. , And a duty ratio of a steering motor rotation speed signal (hereinafter, referred to as a motor rotation speed signal) output to the motor drive circuit 22 in order to increase the motor current. When this motor current exceeds a predetermined value (overcurrent detection level), the overcurrent sensor 8b outputs an overcurrent detection signal, and when this state continues for the motor abnormal current determination time 1 (t1) or longer, the front wheels are subject to curbs or the like. It is determined that the obstacle has been contacted, and the motor current is reduced in order to prevent the failure of the steering control system, so that the duty ratio of the motor rotation speed signal is reduced.

And, even though the duty ratio of the motor rotation signal is reduced and the motor current is reduced,
If the motor current exceeds a specified value (overcurrent detection level),
When the state in which the overcurrent sensor outputs the overcurrent detection signal continues for the motor abnormal current determination time 2 (t1 + t2) or more, it is determined that some failure has occurred in the steering control system,
Make an emergency stop of the vehicle to ensure safety while driving.

Here, the motor speed signal is a so-called digital signal output to the motor drive circuit 22, and when the speed is high, the ratio of the signal output time within a fixed time is increased and the duty ratio is increased. on the other hand,
When the speed is low, the ratio of the signal output time within a fixed time is reduced and the duty ratio is reduced. Figure 5
FIG. 6 shows a flowchart of steering control contents according to the present invention.

In step 1 (abbreviated as S1 in the figure; the same applies hereinafter), the target steering position based on the steering control command is compared with the actual steering position detected by the steer position sensor 8a. In step 2, the rotation direction for driving the steering motor 8 and the magnitude of the drive current are determined based on the comparison result. In step 3, the determined rotation direction and drive signal are output to the motor drive circuit 22 to drive the steering motor 8. The processing of steps 1 to 3 described above is the steering control of the vehicle that is normally performed.

In step 4, the output signal of the overcurrent sensor 8b is monitored. In step 5, it is judged whether or not an overcurrent detection signal is detected, and if it is detected, step 6
If it is not detected, the steering control process is ended. In step 6, the elapsed time is read from the timer that monitors the elapsed time after the overcurrent detection signal is generated. In step 7, it is determined whether or not the elapsed time is longer than or equal to a predetermined time. If it is longer than or equal to the predetermined time, the process proceeds to step 8, and if it is less than the predetermined time, the steering control process is ended.

In step 8, the steering control state (whether or not the steering motor drive current is reduced to protect the steering control system) is checked. In step 9, it is determined whether or not the steering control state is a state in which the drive current is reduced. If it is in the reduced state, the process proceeds to step 11, and if it is not in the reduced state, the process proceeds to step 10. Here, the processing of the above steps 4 to 9 corresponds to the overload determination means according to claim 1 and the failure determination means according to claim 2.

In step 10, the steering motor drive current is reduced to protect the steering control system, and the steering control process is terminated. In step 11, the vehicle is brought to an emergency stop in order to ensure the safety of the vehicle, and the steering control process is ended.

[0027]

As described above, according to the first aspect of the present invention, the load on the steering means is monitored during steering of the vehicle.
When the load exceeds a predetermined value for a predetermined time or longer, for example, it is determined that the front wheels have come into contact with an obstacle such as a curb, and the load on the steering means is set to prevent the steering means from being overloaded. As a result, the failure of the steering control system due to the unreasonable operation after the contact can be reduced.

According to the second aspect of the present invention, it is determined that a failure has occurred in the steering means when the overload state continues for a predetermined time or more even though the overload reduction control of the steering means is performed. However, since the vehicle is brought to an emergency stop, traveling in a state where steering is impossible is eliminated, and safety in traveling the vehicle can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall system configuration of an embodiment of the present invention, in which (a) shows a radio control device and (b) shows a radio control vehicle.

FIG. 2 is a control system block diagram showing the control contents of the above.

FIG. 3 is a block diagram showing a steering control system of the same.

FIG. 4 shows a time chart of an outline of steering control in the above.

FIG. 5 is a flowchart showing the steering control contents of the above.

[Explanation of symbols]

 7 In-vehicle control device (receiver) 8 Steering motor 8b Overcurrent sensor 10 Brake pressure controller 18 CPU

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Sonoda 1-chome, Ichome, Ageo City, Saitama Prefecture Nissan diesel industry Co., Ltd.

Claims (2)

[Claims] 1. In a system for remotely controlling a vehicle wirelessly, a wirelessly controlled vehicle controlled by a wireless controller for wirelessly controlling the vehicle has a steering means for steering the vehicle and a predetermined load on the steering means of the vehicle. Control means for controlling the steering means, an overload detection means for detecting that the value is equal to or more than a value, an overload determination means for judging that the steering means is overloaded when a signal from the overload detection means continues for a predetermined time or more. And a steering control means for performing control for reducing the load on the steering means when it is determined to be overloaded, and a wireless control system for a vehicle. 2. The wirelessly controlled vehicle reduces the load on the emergency stop means for stopping the vehicle and the steering means, and further when the overload determination means determines that the vehicle is overloaded. And an emergency stop control means for performing control to stop the vehicle by the emergency stop means when it is determined that the steering means has a failure. 1. The vehicle radio control system according to 1.