JP2896074B2 - Induction cart - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide cart that automatically travels along a guide line and conveys luggage, people, and the like.

[0002]

2. Description of the Related Art Conventionally, such a guide cart is provided with a traveling device having an engine as a drive source on a vehicle body as shown in Japanese Patent Application Laid-Open No. 5-73144 (G05D 1/202), and is provided along a guide line. And a traveling device for steering the front wheels. A receiver that receives the start and stop operation signals from the transmitter is provided on the vehicle body side, and based on the signals, the vehicle body starts and stops, and an induction cart that can control the vehicle body by operation from a distant place Is generally known. And when driving automatically in such a guide cart,
The control is such that the vehicle runs at a constant speed. When the induction cart starts, the electromagnetic brake is kept in a braking state until the engine speed reaches the rotational speed at which the centrifugal clutch is connected, and the electromagnetic brake is released and started when the centrifugal clutch is connected. It has become.

[0003] However, in the above-described configuration, particularly when traveling downhill on a place such as a golf course where there are large undulations, the electromagnetic brake is released after the centrifugal clutch is engaged. is there.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide an induction cart that can safely travel downhill on a rugged golf course or the like.

[0005]

SUMMARY OF THE INVENTION The present invention comprises a main body that automatically travels along a guide line, a brake motor that operates a brake that brakes wheels, a speed sensor that detects a vehicle speed of the main body, A downhill detecting means for detecting that the traveling road is downhill, and setting a plurality of predetermined reference speeds and a plurality of predetermined brake motor operations having different braking amounts; When the means detects a downhill, the brake is operated intermittently, and when the vehicle reaches each of the reference speeds, the operation of the brake motor is controlled so that the braking amount increases as the vehicle speed increases. A main controller is provided.

Further, a main body that automatically travels along a guide line, a brake motor that operates a brake that brakes wheels, a speed sensor that detects a vehicle speed of the main body, and a running path of the main body is downhill. And a plurality of predetermined reference speeds and a plurality of predetermined brake operations with different braking times are set, and the downhill detection means is a downhill. A main controller that intermittently operates the brake when detected, and controls the operation of the brake motor such that the braking time increases as the vehicle speed increases when the reference speeds are reached. And

[0007]

[0008]

According to the present invention, when a downhill is detected by the downhill detecting means, the brake is operated intermittently to prevent wheels from slipping and to further reduce brake wear. Further, the brake is not heated and the braking force does not decrease, so that it is very safe.

Further, a plurality of reference speeds are set in advance, the brakes are intermittently operated when the speed gradually increases and reaches the first reference speed, and when the speed further increases and reaches the next reference speed, The brake is interrupted with a larger braking amount than at the initial reference speed. If the vehicle still does not decelerate, control is performed so as to interrupt the brake with a larger braking amount when the next reference speed is reached. At this time, the braking times are all the same. In other words, the faster the vehicle speed, the more the vehicle is decelerated with a greater amount of braking,
In addition to being able to reliably maintain vehicle speed, it also prevents wheels from slipping,
In addition, brake wear is reduced. Further, the brake is not heated and the braking force does not decrease, so that it is very safe.

Further, a plurality of reference speeds are set in advance, and the brakes are intermittently operated when the speed gradually increases and reaches the first reference speed, and when the speed further increases and reaches the next reference speed. Operate the brake for a longer time than at the initial reference speed. If the vehicle still does not decelerate, control is performed so that the brake is interrupted for a longer time when the next reference speed is reached. At this time, the braking amounts are all the same. That is, the faster the vehicle speed,
Since the braking time is prolonged and the vehicle is decelerated, the vehicle speed can be reliably maintained, the wheels are prevented from slipping, and the brake wear is further reduced. Further, the brake is not heated and the braking force does not decrease, so that it is very safe.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings, taking a guided golf cart as an example.

Reference numeral 1 denotes a golf cart main body for carrying a person and a load such as a golf bag.
And a front wheel 3 which is steered forward of the frame 2 and a rear wheel 4 which is driven rearward. This golf cart body 1
In the manual operation mode in which a person can drive freely by driving, and by operating a remote control transmitter (not shown), the vehicle can be operated and stopped from a remote location, and a guide line (not shown) buried in the ground can be operated. And an automatic driving mode in which the vehicle travels by detecting a magnetic field along the vehicle.

Reference numeral 5 denotes a roof that covers the main body 1. The roof 5 is formed of resin, and is supported by a rear stay 6 at the rear. Further, the front of the roof 5 is formed of a colorless and transparent resin with good visibility, and is attached to the front of the main body 1.

A front cowl 7 covers the front wheel 3 and the frame 2 in front of the main body 1. The front cowl 7 is formed of resin.

Reference numeral 8 denotes a rear cowl that covers the rear wheel 4 and the frame 2 at the rear of the main body 1. The rear cowl 8 is also made of resin, like the front cowl 7.

Reference numeral 9 denotes a bag stand provided on the rear cowl 8 behind the rear stay 6, and the bag stand 9 is capable of placing a plurality of golf bags (not shown) in parallel. .

Reference numeral 10 denotes a seat on which a person rides.
They are arranged side by side so that two people can sit side by side.

Reference numeral 11 denotes a handle for steering the front wheel 3 in the manual operation mode. The handle 11 operates a rack and pinion 14 via a handle stay 12 and an automatic manual switching device 13 so that the front wheel 3 moves. It has become.

Reference numeral 15 denotes an automatic / manual switching lever for connecting and disconnecting gears in the automatic / manual switching device 13.
The switching lever 15 connects the handle 11 with a gear in the manual operation mode, separates the gear in the automatic operation mode, and fixes the handle 11 so as not to rotate freely. The automatic manual switching lever 15 is
A switch (not shown) capable of switching control between an automatic operation mode and a manual operation mode is provided in the automatic manual switching device 13 together with the connection and disconnection of the handle 11.

Reference numeral 16 denotes a steering motor for moving the rack and pinion 14 in the automatic operation mode. The steering motor 16 is a left and right guidance signal sensor 17 provided in front of the main body 1 for detecting a magnetic field from the guidance wire. It operates based on the guidance signal from the. The guidance signal sensor 17
The steering wheel 16 is attached to the tip of the sensor stay 18 and operates the steering motor 16 to steer the front wheel 3 so that the guide line is always located at the center of the guide signal sensor 17.

Reference numeral 19 denotes a guide wire sensor attached to the sensor stay 18 for detecting a signal from the guide wire and detecting that the main body 1 is not derailed from the guide wire.

Reference numeral 20 denotes an engine serving as a driving source. The engine 20 uses a 250 cc OHV type engine. A centrifugal clutch 21 is connected to the output shaft of the engine 20, and a driven pulley is
23 is designed to rotate. The centrifugal clutch 21,
The driven pulley 23 has a mechanism in which the tension of the V-belt 22 changes in accordance with the rotation speed of the rotation shaft of the engine 20, and thereby the speed is changed.

Reference numeral 24 denotes a gear box for reducing the rotation speed of the driven pulley 23 to rotate the axle 25 and rotate the rear wheel 4.

Reference numeral 26 denotes a parking brake for fixing the axle 25 and stopping the main body 1. The parking brake 26 pulls one side of an arm 27 that rotates about a substantially central portion by a spring 28. The parking brake 26 is applied by pulling. When the parking brake 26 is released, the parking brake motor 29 that rotates the arm 27 in a direction opposite to the bias of the spring 28 is operated.

Reference numeral 30 denotes a starter motor for starting the engine 20. The starter motor 30 is connected to the centrifugal clutch 21 and the dynamo 32 by a belt 31.

Reference numeral 33 denotes an air cleaner.

Reference numeral 34 denotes a brake pedal for operating a brake provided on the rear wheel 4, that is, a drum brake 60 (described later), which is different from the parking brake 26. The drum brake 60 operates according to the operation amount via the wire 35. In the automatic operation mode, when a stop, deceleration, or the like is instructed, the brake rod 36 is pulled by operating the brake motor 36, and the brake wire 35 is pulled in accordance with the operation amount, and the drum brake 60 Is supposed to work. Apart from this embodiment, the drum brake 60 may be provided not only on the rear wheel but also on the front wheel.
Further, a disc brake may be used separately from the drum brake.

Numeral 38 denotes an accelerator pedal for adjusting the speed in the manual operation mode. A potentiometer 53 (described later) is attached to the accelerator pedal 38.
The rotation speed of the engine 20 is changed according to the movement of the potentiometer 53.

Numeral 39 is a bumper provided in front of the front cowl 7, and the bumper 39 can be moved forward and backward. When the bumper 39 moves toward the main body 1, that is, when it hits something while traveling, The traveling is stopped, and the parking brake 26 is applied.

An obstacle sensor 40 detects an obstacle in front of the vehicle. The obstacle sensor 40 transmits an ultrasonic wave forward,
If there is an obstacle, the reflected ultrasonic wave is detected to detect the presence of the obstacle, and the main body 1 is controlled to stop.

Reference numeral 41 denotes a tracking receiver provided in front of the front cowl 7, and reference numeral 42 denotes a tracking transmitter provided behind the rear cowl 8. The tracking transmitter 42 outputs an electromagnetic wave. When the golf cart exists in front, the golf cart body 1 is stopped by receiving the electromagnetic wave output from the front by the golf cart behind. At this time, the receiving sensitivity is set so as to stop at a predetermined distance. The tracking transmitter 41 and the tracking receiver 42 are collectively referred to as a tracking sensor 43.

Reference numeral 66 denotes a forward / reverse switching lever provided on the side surface of the main body 1. By moving the forward / backward switching lever 66, a gear in the gear box 24 can be moved to switch the traveling direction.

Reference numeral 44 denotes a control box containing a control board for controlling the travel of the golf cart body 1 and the like.

Next, the control circuit will be described with reference to FIG.

Reference numeral 45 denotes a remote control transmitter for instructing traveling and stopping in the automatic operation mode.
The operation can be controlled by sending a signal to a remote control receiver 46 provided in the main body 1.

Reference numeral 47 denotes a start / stop switch for switching between a running state and a stopped state, and sends a signal for turning on / off the start / stop switch 47 to the main controller 48. The start / stop switch 47 and the remote control transmitter 45 are referred to as start / stop means.

Reference numeral 49 denotes an alarm display for notifying an abnormality of the main body 1, and the alarm display 49 displays the state of the engine 20 and the like.

Reference numeral 50 denotes a temperature sensor for detecting an ambient temperature. The temperature sensor 50 sends temperature information to the main controller 48, and operates a choke solenoid 51 based on the information. Adjust the amount of fuel sent to

Reference numeral 53 denotes an accelerator depression sensor which is attached to the accelerator pedal 38 and detects whether or not the accelerator pedal 38 is depressed. The accelerator depression sensor 53 uses a micro switch. Further, a potentiometer 65 for detecting a depression amount of the accelerator pedal 38 and transmitting a signal to the main controller 48 is provided near the accelerator pedal.

Reference numeral 54 denotes a battery serving as a power source for the parking brake motor 29, the steering motor 16, and the like, which is a 12-volt battery.

Reference numeral 55 denotes a switch for turning the power supply to the battery 54 on and off.

Reference numeral 56 denotes a throttle lever for adjusting the number of revolutions of the engine 20. The throttle lever 56 is operated by an accelerator motor 57 in response to a signal from the main controller 48.
Is driven and moved.

Reference numeral 58 denotes a foot brake depression sensor for detecting the operation of the brake pedal 34. The foot brake depression sensor 58 is turned on when depressed by a micro switch.

Reference numeral 59 denotes a brake position sensor for detecting the operating position of the brake motor 36 for operating the brake, in this embodiment, the drum brake 60, during traveling in the automatic driving mode. The amount of operation of the drum brake 60 can be determined by the amount of operation of the brake motor 36, and the elongation of the brake wire 35 can be detected by previously determining 0% and 100% of the amount of operation of the drum brake 60. Can be.

A speed sensor 61 detects the rotation of the rear wheel 4 to detect the vehicle speed.

Reference numeral 62 denotes a magnet sensor for detecting a magnetic field from a magnet (not shown) buried in the ground. The magnet sensor 62 can distinguish between the N pole and the S pole of the magnet. Utilizing this, the embedded magnets are embedded at 60 cm intervals in combination of NN, SN, etc., and commands for speed control and stop such as stopping, lowering the speed by one stage, medium speed operation, etc. It is carried out. Also, set the NS interval to 1 to indicate that the downhill is starting.
It is embedded at intervals of 20 cm, and runs downhill when the magnet sensor 62 detects it. The magnet sensor 62 for detecting the embedded magnet is also a so-called downhill detecting means.

An accelerator rotation amount sensor 63 detects the amount of rotation of the accelerator motor 57. The amount of rotation of the accelerator motor 57 is determined by the accelerator rotation amount sensor 63.

Reference numeral 64 denotes a rotation speed sensor for detecting the cycle of the spark of the engine 20 to detect the rotation speed of the engine 20.

Reference numeral 67 denotes a downhill detecting means provided in the control box 44 for detecting the inclination when the main body 1 stops, that is, an inclination sensor. The inclination sensor 67 uses a magnetoresistive element. The resistance value changes according to the inclination, and detects whether the main body 1 is on an uphill or a downhill. Then, this value is input to the main controller 48, and a start operation is performed according to the inclination. The downhill detecting means performs detection by the magnet when the main body 1 is running, and performs detection by the inclination sensor 67 when the main body 1 is stopped.

Next, the operation will be described.

In the manual operation mode, the switch 55
, And the automatic manual switching lever 15 provided near the handle 11 is set to the manual position so that the vehicle can run. The start / stop switch 47 is set to a startable state, and when the accelerator pedal 38 is depressed, a signal is input from the potentiometer 65 to the main controller 48, and the accelerator motor 57 rotates in accordance with the depressed amount to rotate the engine 20. The number goes up. When the engine 20 starts, the centrifugal clutch 21, the V-belt 22, the driven pulley 2
3. The rear wheel 4 rotates through the gear box 24.

The front wheel 3 is steered by a steering wheel 11, and the traveling speed can be freely increased up to 19 km / h by an accelerator pedal.
Adjustable by 38.

When stopping or decelerating, the brake wire 35 is pulled by the brake pedal 34 and the drum brake 60
multiply.

Next, the automatic operation mode will be described. The running state is shown in the flowchart of FIG.

First, the automatic manual switching lever 15 is set to automatic, the handle 11 is fixed so as not to rotate, and the automatic operation mode is switched. Before this, it is confirmed that there is no stop signal, for example, a signal from the obstacle sensor 40 and the follower sensor 43 from the bumper 39.

When a traveling start signal is received from the remote control transmitter 45, the engine 20 is started and the operation shifts to a start operation.
This starting operation will be described in detail with reference to FIG. When the main body 1 starts,
The guide signal sensor 17 receives a magnetic field generated from the guide line, and the main body 1 runs along the guide line. The running speed is controlled by a magnet buried in the ground.

In the above-mentioned automatic operation mode, the traveling speed can be set to three stages of 10 km / h, 6 km / h, and 4 km. When the speed is reduced from 6 km to 4 km by the magnet, After driving 10 meters, it will return to 6 km / h. For example, if it is desired to continue running at a speed of 4 km / h, if the instruction of the magnet at 4 km / h is given once again from the first position indicated by the magnet to 10 meters, the vehicle will run for an additional 10 meters. . When the speed is increased from 6 km to 10 km, an instruction of 10 km is given by the magnet as in the case described above. In this case, 5
After traveling 0 meters, the speed returns to 6 km / h. In this case, as in the case described above, if the driver wants to travel 50 meters or more, it is necessary to move 5 meters from the position indicated by the first magnet.
If you give a 10km / h magnet command again by 0m, you will run at 10km.

If a stop command is issued during running, the engine 20 must be rotated at a speed such that the centrifugal clutch 21 cannot be disengaged. The motor 36 is operated, and the engine brake and the drum brake 60 are used together. Then, it is confirmed that the vehicle speed has reached 3 km / h, and the engine brake is released. When the vehicle speed is 0 km, that is, when the vehicle has stopped, the parking brake 26 is operated and stopped. Similarly, when the vehicle is approaching a steep slope, the speed is reduced by the brake motor 36 while maintaining the potentiometer 65 at 20%, and the speed is reduced while using the engine brake sufficiently.

At this time, a stop instruction is issued from a magnet buried in the ground, a follow-up sensor 43, a remote control transmitter 45, or the like.
This is performed by a signal from the device.

Next, the starting operation will be described with reference to the flowchart of FIG.

When the engine 20 is started, the inclination sensor 67 detects at what inclination the main body 1 is stopped.
If not, the main controller 48 determines that the vehicle is on an uphill, and the brake motor 36 operates with 50% force to operate the drum brake 60. Then, the parking brake 65 is released, the engine speed is increased by the accelerator motor 57, the driving force is applied to the main body 1, the brake motor 36 is loosened, and the drum brake 65 is gradually released. In the case of an uphill, the release of the brake motor 36 gradually returns from the 50% operating state to the release direction. At the same time, the engine speed is gradually increased by the accelerator motor 57.

When the vehicle is started at an inclination angle of less than 5 degrees, -1
If it is 0 degree or more, it is determined that the vehicle is stopped on a flat ground, and the brake motor 36 operates with 25% of the force, and the drum brake 60 operates. Then, the parking brake 65 is released, the engine speed is increased by the accelerator motor 57, the driving force is increased, and the brake motor 36 is loosened.
65 is gradually released. For flat ground, brake motor
The release of 36 returns from the 25% operating state to the release direction at the same rate of change as when climbing uphill. At the same time, the engine speed is gradually increased by the accelerator motor 57. In this way, the drum brake 60 is released at the same rate of change as when climbing a hill, so that the drum brake 60 is released earlier than when climbing a hill, and the vehicle can move to a running state earlier. Also, since the operation of the accelerator motor 57 is made smaller than the rate of change when climbing a hill, the vehicle does not start suddenly and is safe.

Next, when the inclination angle is less than -10 degrees at the time of starting, it is detected that the vehicle is stopped on a downhill, and the brake motor 36 is operated with a 25% force to release the parking brake 65. Then, the accelerator motor 57 is operated to increase the engine speed, and the brake motor 36 is gradually operated in the direction in which the drum brake 60 is released. At this time, when the angle of the downhill is large, the operation of the brake motor 36 is set to 25%. However, during stoppage, the parking brake 65 is working, so that the brake is surely stopped by the double brake. In the case of a downhill, the release of the brake motor 36 gradually returns from the 25% operating state to the release direction.
At the same time, the engine speed is gradually increased by the accelerator motor 57. In this way, the drum brake 60 is released at the same rate of change as when traveling on level ground, so that the drum brake 60 is released earlier than when traveling on an uphill, as in the case of traveling on level ground, and the vehicle can move to the traveling state earlier. Further, since the operation of the accelerator motor 57 is made smaller than the rate of change at the time of uphill as in the case of the flat ground, it is safe without sudden start.

Further, in the case of a downhill, if the drum brake 60 is gradually released, the traveling speed may increase. Therefore, a plurality of reference speeds, in this embodiment, 3 per hour
The speed is set to 3 km / h, 4 km / km, and the drum brake 60 is operated intermittently at the speed of 3 km / h, that is, the pumping brake is operated to prevent the rear wheel 4 from slipping on rough roads. . The braking action at this time is 3
As shown in FIG. 6, the drum brake 1 at the time of kilometer,
Operates with a brake motor 36 operation amount of 30% for 0.8 seconds,
Subsequently, the operation is repeated until the vehicle is decelerated by repeating the release for 0.2 seconds. When the vehicle is further accelerated on a downhill or the like, the brake operation at a speed of 4 km / h, as shown in FIG.
36 operation amount is operated for 0.8 seconds and released for 0.2 seconds continuously. Then, when the speed reaches 5 km / h, as shown in FIG. 6, the operation of the drum brake 3 at 50% of the brake operation amount is operated for 0.8 seconds and release for 0.2 seconds is continued. Then, if a downhill release signal is detected during the intermittent operation of the drum brake, for example, if a downhill release instruction is detected by a magnet or the like, downhill traveling is released,
Return to normal driving. Further, if the vehicle speed has not reached the set speed, that is, if the vehicle speed has not reached 4 km or 5 km, a determination is made at the reference speed that is one speed lower, and the vehicle always travels at a speed of 3 km or less. It is set as follows. In the determination of the reference speed of 3 km / h, if the speed is 3 km / h or less, the drum brake is not interrupted, and the vehicle travels after the release signal is input.

As another embodiment, when a downhill is detected, as shown in FIG.
The judgment is made based on the two reference speeds. This is the same as the above-described embodiment, and a description thereof will be omitted.

In the present embodiment, the above-described drum brake 1,
The operation contents of the drum brake 2 and the drum brake 3 are different, and the brake operation in the present embodiment is as follows. As shown in FIG. It operates with 36 motion quantities, then
It repeats until it decelerates by repeating release for 2 seconds. When the vehicle is further accelerated, the brake operation at a speed of 4 km / h, as shown in FIG. 7, operates the brake motor 36 of 40% as the drum brake 2 for 1.0 second and releases it for 0.2 seconds. Things to continue. Then, when the speed reaches 5 km / h, as shown in FIG. 7, as the drum brake 3, a brake operation amount of 40% is operated for 1.2 seconds, and releasing for 0.2 seconds is continued. Then, when a downhill release signal, for example, an instruction to release the downhill by a magnet or the like is detected during the intermittent operation of the drum brake, the downhill traveling is released and the vehicle returns to the normal traveling. As described above, the operation amount of the brake motor 36 is constant at 40%, and by changing the operation time according to the speed, the same effect as described above can be obtained.
That is, the higher the vehicle speed, the more the vehicle is decelerated with a greater amount of braking, so that the vehicle speed can be reliably maintained, the wheels 4 are prevented from slipping, and the wear of the drum brake 60 is further reduced. Then, the drum brake 60 is not heated and the braking force does not decrease, so that it is very safe.

In this embodiment, the brake is used as the drum brake 60.
However, anything that applies a braking force such as a disc brake may be used.

[0068]

According to the present invention, when the downhill detecting means detects a downhill, the brake is operated intermittently, so that the wheels are prevented from slipping and the wear of the brake is further reduced. Further, the brake is not heated and the braking force does not decrease, so that it is very safe.

Further, in the downhill traveling, when the respective reference speeds are reached, the brake motor is operated so that the braking amount is increased as the vehicle speed is increased. As a result, the vehicle speed can be reliably maintained, the wheels are prevented from slipping, and the wear of the brakes is further reduced. Further, the brake is not heated and the braking force does not decrease, so that it is very safe.

Further, in the downhill traveling, when the respective reference speeds are reached, the brake motor is operated to increase the braking time as the vehicle speed increases. Therefore, the higher the vehicle speed, the longer the braking time and deceleration. As a result, the vehicle speed can be reliably maintained, the wheels are prevented from slipping, and the wear of the brakes is further reduced. Further, the brake is not heated and the braking force does not decrease, so that it is very safe.

[Brief description of the drawings]

FIG. 1 is a component arrangement view of a guide cart according to an embodiment of the present invention as viewed from a side.

FIG. 2 is a component layout view as viewed from above.

FIG. 3 is a block diagram of the control circuit.

FIG. 4 is a flowchart showing a traveling state in the automatic driving mode.

FIG. 5 is a flowchart showing a start operation in the automatic mode.

FIG. 6 is a diagram showing a state of an intermittent brake operation during the downhill traveling.

FIG. 7 is a diagram illustrating a state of an intermittent brake operation during downhill traveling in another embodiment.

[Explanation of symbols]

 1 Body 4 Driving wheel 60 Drum brake (brake) 36 Brake motor 62 Magnet sensor (Downhill detecting means) 67 Incline sensor (Downhill detecting means) 48 Main controller 61 Speed sensor

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A63B 5/08 G05D 1/02

Claims (2)

(57) [Claims] 1. A main body that automatically travels along a guide line, a brake motor that operates a brake that brakes wheels, a speed sensor that detects a vehicle speed of the main body, and a running path of the main body is downhill. A plurality of predetermined reference speeds, and a plurality of predetermined brake motor operations having different braking amounts.The downhill detecting means detects that the downhill detecting means is a downhill. A main controller that intermittently operates the brake when detected and controls the operation of the brake motor so that the braking amount increases as the vehicle speed increases when the reference speeds are reached. And induction cart. 2. A main body that automatically travels along a guide line, a brake motor that operates a brake that brakes wheels, a speed sensor that detects a vehicle speed of the main body, and a running path of the main body is downhill. And a plurality of predetermined reference speeds, and a plurality of predetermined braking operations with different braking times are set, and the downhill detecting means is a downhill. A main controller that intermittently operates the brake when detected, and controls the operation of the brake motor such that the braking time increases as the vehicle speed increases when the reference speeds are reached. And induction cart.