JP2000235416A - Autonomously traveling robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an autonomously traveling robot capable of preventing an obstacle which is already damaged by impact caused by collision from being further damaged by stopping a driving motor for traveling a device main body when the device main body is stopped by an obstacle with which the device main body collides. SOLUTION: A load torque detecting part 20 detects the size of a load torque imposed on a traveling motor 11, and judges whether or not the device main body is stopped by an obstacle from the size of the detected load torque. The control part 10 stops the motor 11 for traveling at the time of judging that the device main body is stopped by the obstacle. Thus, it is possible to prevent the device main body and the obstacle with which the device main body collides from being damaged by any factor other than the impact due to the collision without applying large load torque on the traveling motor 11 for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-contained traveling robot such as a cleaning robot, an automatic transfer robot or a guide robot having an independent traveling function.

[0002]

2. Description of the Related Art Conventionally, there have been various types of self-propelled robots, such as a cleaning robot for cleaning a room, a transport robot for transporting luggage, and a guide robot for guiding facilities such as department stores. The self-contained traveling robot is provided with driving wheels and the like that are rotationally driven by a driving motor as a self-contained traveling function, and controls traveling (movement) of the apparatus body by known optical guidance means or inertial navigation using a gyro. Was. It also has a function to detect the presence or absence of an obstacle and the distance to the obstacle using an ultrasonic sensor or the like arranged on the main body, and to control the running speed and the running direction to run the main body of the apparatus while avoiding the obstacle. Was.

[0003] For example, a cleaning robot is provided with a drive wheel that is driven to rotate by a drive motor, and drives the apparatus body by inertial navigation using an optical guiding means or a gyro.
Dust such as dust and dirt is sucked into the inside of the main body from the floor surface opposite to the suction port provided at the bottom of the main body to perform cleaning. In addition, the cleaning robot detects a front wall (obstacle) with an ultrasonic sensor or the like disposed on the main body, controls a traveling speed according to a distance to the detected wall, and makes a U-turn when the vehicle reaches the wall. At this time, the entire room is cleaned by repeating the reciprocating operation of moving the sideways by the same amount as the width of the suction port.)

[0004]

As described above, the conventional self-propelled robot detects the presence or absence of an obstacle and the distance to the obstacle by means of an ultrasonic sensor or the like disposed on the main body to avoid the obstacle. It had the function of running the device body while running.

However, when a person or an object approaches the robot body, even if the approaching person or object is detected as an obstacle by the robot body, a collision may occur without avoiding the obstacle. there were. In addition, an obstacle (particularly, a step or a thin rod-shaped object, etc.) may be located in a blind spot of an ultrasonic sensor or the like, and may collide without being able to detect the obstacle. The robot that has collided with the obstacle is stopped by the obstacle because the traveling path is blocked by the obstacle or the robot cannot get over the obstacle. At this time, the conventional self-propelled mobile robot travels through the apparatus main body even though the main body is stopped by colliding with an obstacle (it is not recognized that the main body is stopped by the obstacle). Therefore, there is a problem that an excessive load is applied to the self-sustained traveling function including the drive motor, and the main body of the apparatus is damaged (burn of the drive motor, damage of the drive wheels, and the like). Further, since the main body of the apparatus keeps pressing the colliding obstacle, there is another problem that the obstacle damaged by the impact of the collision is further damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to stop the drive motor for driving the apparatus main body when the apparatus main body is stopped by the colliding obstacle, so that the obstacle damaged by the impact due to the collision is not further damaged. An object of the present invention is to provide an independent traveling robot.

Another object of the present invention is to provide a self-propelled robot capable of reducing damage to the apparatus body and the colliding obstacle due to the collision by alleviating the impact at the time of collision with the obstacle.

It is a further object of the present invention to provide a self-contained traveling robot that can easily move a stopped apparatus body to a desired position.

[0009]

Means for Solving the Problems (1) In a self-contained traveling robot provided with traveling means for causing the apparatus body to travel independently by a drive motor, load torque detection for detecting the magnitude of the load torque applied to the drive motor Means, and drive motor stopping means for stopping the drive motor when the magnitude of the load torque detected by the load torque detecting means exceeds a predetermined limit.
(Claim 1) In this configuration, when a load torque exceeding a predetermined limit is applied to the drive motor for running the apparatus body, the drive motor is stopped. As is well known, when the main body of a device climbs over a step or the like (cannot get over) or collides with another object, if the main body of the device is stopped, the driving motor causes the driving motor to be more intense than during normal traveling. Large load torque. Therefore, if the above-described limit is appropriately defined, the drive motor can be stopped when the apparatus main body is stopped by an obstacle.
Therefore, a very large load torque is not applied to the drive motor for a long time, and damage to the apparatus main body such as the drive motor and the drive wheels can be prevented. In addition, since the drive motor is stopped, the obstacle is not pressed against the apparatus main body for a long time, so that the damage can be prevented from spreading further.

(2) The drive motor stopping means is means for stopping the drive motor after moving the main body by a predetermined distance by the traveling means. (Claim 2) In this configuration, when the apparatus main body is stopped by colliding with an obstacle, the apparatus main body is moved by a predetermined distance and then the drive motor is stopped. Can be forgiven.

(3) In the invention of (2), the drive motor stopping means may be means for stopping the drive motor after the main body is moved back by a predetermined distance by the traveling means.

[0012] In this way, the apparatus main body is backed up when it collides with an obstacle, so that the impact due to the collision is reduced, and damage to the apparatus main body and the obstacle can be reduced.

(4) There is provided a limit changing means for changing the limit. (Claim 3) As is well known, the magnitude of the load torque applied to the drive motor varies depending on the floor surface (carpet, tile, etc.) on which the apparatus body is running. In this configuration, the magnitude of the load torque, which is a threshold value for determining that the apparatus main body has stopped due to collision with an obstacle, can be changed. Type).

(5) In the invention of (4), the limit amount changing means may be means having an operation unit for inputting the limit amount by operating a key or the like.

[0015] In this way, the user can set the limit value according to the environment in which the apparatus body is used.

(6) In the invention of (4), the limit amount changing means includes a sensor for detecting a state of the floor surface, and sets the limit amount in accordance with the state of the floor surface detected by the sensor. It may be a means for setting.

With this configuration, the limit value is automatically set in accordance with the state of the floor surface detected by the sensor, so that the user can set the limit value in accordance with the environment in which the apparatus body is used. It does not make you feel annoying.

(7) When the drive motor is stopped by the drive motor stopping means, a notifying means is provided for notifying the surroundings of a subsequent operation of the apparatus main body. (Claim 4) In this configuration, since the subsequent operation of the apparatus main body is notified at the time of stop, the surrounding body is informed of how the apparatus main body stopped after colliding with an obstacle will operate. Can do so without giving anxiety to the people around him.

(8) In the invention of (7), the notification means may have a display unit for displaying a message.

In this configuration, a message about the subsequent operation of the apparatus main body is displayed on the display unit to notify the surroundings.

(9) In the invention of (7), the notification means may have a voice output unit for outputting a message by voice.

In this configuration, a message about the subsequent operation of the apparatus main body is output from the audio output unit to notify the surroundings.

(10) In a self-contained traveling robot provided with a traveling means for causing the apparatus main body to travel independently by a drive motor, a load torque detecting means for detecting a magnitude of a load torque applied to the drive motor; When stopping, when the magnitude of the load torque detected by the load torque detection means exceeds a certain amount, movement control means for moving the apparatus main body by a predetermined distance in a direction in which the load torque is applied by the traveling means, It has. (Claim 5).

In this configuration, when a load torque of a predetermined amount or more is applied to the drive motor when the apparatus main body is stopped, the traveling means moves the apparatus main body by a predetermined distance in the direction in which the load torque is applied. Further, when the apparatus main body in which the drive motor is stopped is pressed in an arbitrary direction, a load torque is applied to the drive motor in the direction in which the apparatus main body is pressed. Therefore, when the user pushes the stopped apparatus body in the direction in which he / she wants to move, the apparatus moves the apparatus body by a predetermined distance in the direction in which the traveling apparatus is pushed, so that the stopped apparatus body can be easily moved to a desired position. Can be done.

(11) The movement control means includes means for controlling the movement speed of the apparatus body based on the magnitude of the load torque detected by the load torque detection means. (Claim 6) In this configuration, the apparatus main body is moved by a predetermined distance in the direction in which the user presses the apparatus main body at a stop at a speed corresponding to the magnitude of the pressing force. Therefore, the user can control the moving speed of the apparatus main body according to the magnitude of the pressing force on the apparatus main body, so that the apparatus main body can be more easily moved to a desired position.

[0026]

FIG. 1 is a sectional view of a cleaning robot main body according to an embodiment of the present invention, FIG. 2 is a view taken in the direction of arrows AA in FIG. 1, and FIG. FIG. 4 is a block diagram showing the function of (1). In the figure, 1 is a cleaning robot main body, 2 is two driving wheels arranged on the left and right of the main body bottom, 3 is a driven wheel rotatably mounted on the main body bottom, and 4 is operated by the cleaning robot 1 main body. It is a battery that supplies power. 5 is a blower having a fan, 6 is a dust collecting chamber for collecting dust and dirt sucked into the main body, 7 is a suction port provided at the bottom of the main body and sucks dust and dirt, and 8 is A pipe connecting the suction port 7 and the dust collection chamber 6, and 9 is a brush provided in the suction port 7.
The fan 5, the dust collection chamber 6, the suction port 7, the pipe 8 and the brush 9 are components for realizing the function of a vacuum cleaner.

In FIG. 3, reference numeral 10 denotes a control unit (control board) for controlling the operation of the main body. The cleaning robot 1 is provided with a traveling motor 11, a suction motor 12, and a brush motor 13, and the traveling motor 11 is
The suction motor 12 is a motor that rotates a fan provided in the blower 5, and the brush motor 13 is a motor that rotates the brush 9 provided in the suction port 7. It is a motor that rotates. Each motor (running motor 11, suction motor 12, and brush motor 13) is controlled by the control unit 10.

Further, a plurality of ultrasonic sensors 14 are disposed around the main body of the cleaning robot 1, and the control unit 10 determines whether there is an obstacle around the main body of the apparatus based on the detection results of the plurality of ultrasonic sensors 14. And the distance to obstacles. Reference numeral 15 denotes a display / operation unit for displaying an operation state of the cleaning robot 1 and performing an input operation. Reference numeral 20 denotes a load torque detecting unit that detects a torsion amount of a transmission shaft (not shown) between the traveling motor 11 and the driving wheels 2. The control unit 10 controls the amount of torsion of the transmission shaft detected by the load torque detecting unit 20. Thus, the magnitude of the load torque applied to the traveling motor 11 is detected.

Hereinafter, the operation of the cleaning robot 1 according to this embodiment will be described. The cleaning robot 1 of this embodiment operates in the following two operation modes. Normal mode This is a mode in which the suction motor 12 and the brush motor 13 are rotated at a high speed for cleaning, and the suction force of dust at the suction port 7 is relatively strong. Quiet mode This is a mode in which the suction motor 12 and the brush motor 13 are rotated at a low speed for cleaning, and the dust suction force at the suction port 7 is weaker than in the normal mode. However, by making the traveling speed (moving speed) of the vacuum cleaner 1 slower than in the normal mode, the time when the suction port 7 faces the same floor surface is made longer than in the normal mode, and dust is left unsucked due to a decrease in suction force. Has been prevented. In addition, the silent mode is used for the traveling motor 11,
Since the suction motor 12 and the brush motor 13 are rotated at a lower speed than in the normal mode, the noise generated from the main body during operation is small, and the operation mode is suitable for cleaning when the surroundings are quiet such as at night. is there. Display / operation unit 1
In No. 5, by performing a predetermined operation, the normal mode and the silent mode can be switched, and the currently set operation mode (the normal mode or the silent mode) is performed.
Is displayed, and the user can easily confirm the set operation mode.

When the operation of starting the cleaning operation is performed on the display / operation section 15, the cleaning robot 1 operates (performs cleaning) in the set operation mode (normal mode or silent mode).

During operation in the normal mode or the silent mode, the control unit 10 detects obstacle information (existence or absence of an obstacle such as a wall surface, etc.) from detection results (outputs) of a plurality of ultrasonic sensors 14 provided around the main body. In addition to detecting the distance to the obstacle, the main body of the cleaning robot 1 is detected by using the detected obstacle information and a pre-stored map information file of a room or the like to be cleaned (a file indicating a moving route of the main body of the cleaning robot 1). Is controlled (such as avoiding obstacles). In the cleaning robot 1 of this embodiment, the direction of the apparatus main body is changed by making the rotation of the two drive wheels 2 by the traveling motor 11 different. Further, the control unit 10 rotates the fan provided in the blower 5 by the suction motor 12 while rotating the brush 9 arranged in the suction port 7 by the brush motor 13, and the floor facing the suction port 7. Dirt such as dust and dirt is sucked into the body from the surface.

As described above, in the cleaning robot 1 of this embodiment, the traveling of the apparatus body is controlled using the detected obstacle information. However, a step on the floor surface or a thin rod-shaped object is detected as an obstacle. There are times when you can't. At this time, if the cleaning robot 1 rides on this step or a rod-shaped object (if it cannot get over it), the drive wheel 2 is locked or spins, and the apparatus main body cannot run (a state stopped by an obstacle). Become. At this time, a very large load torque is applied to the traveling motor 11 as compared with the normal traveling.

FIG. 4 is a diagram showing the magnitude of the load torque applied to the traveling motor. In the figure, T0 is the timing when the rotation of the traveling motor 11 starts, T1 and T2 are normal running times, T2 and T3 are steps, the apparatus main body is stopped and the driving wheels 2 are locked, and T3 and T4 are driving wheels. When 2 is idling, T4 is the timing when the traveling motor 11 is stopped. As shown in FIG. 4, when the driving wheel 3 is locked or idling, the traveling motor 1
1 has a much larger load torque than during normal running.

The controller 10 detects the magnitude of the load torque applied to the traveling motor 11 from the amount of twist of the transmission shaft between the traveling motor 11 and the drive wheel 2 detected by the load torque detector 20. And the traveling motor 1 detected
If the first load torque exceeds a predetermined limit (the amount indicated by a broken line in FIG. 4), the traveling motor 11 is stopped. That is, by appropriately setting the above-mentioned limit amount,
The control unit 10 stops the traveling motor 11 when the main body is stopped by an obstacle to prevent a very large load torque from being applied to the traveling motor 11 for a long time. The drive wheel 2 can be prevented from being damaged.

When a moving object such as a person approaching the main body of the cleaning robot 1 collides with the cleaning robot 1 and the main body of the apparatus is stopped, a very large load torque exceeding the limit is applied to the traveling motor 11. It takes. Therefore, since the control unit 10 stops the traveling motor 11, it is possible to prevent the traveling motor 11 and the driving wheel 2 from being damaged, and the moving object that has collided after the collision is not pressed for a long time. It is possible to prevent the further damage of the moving object and the cleaning robot 1 from being further expanded (the obstacles damaged by the impact due to the collision are not further damaged).

Further, in the above embodiment, when the cleaning robot 1 recognizes that the cleaning robot 1 has been stopped by an obstacle (when the load torque of the traveling motor 11 exceeds the limit amount), the traveling motor 11 is immediately stopped. However, the traveling motor 11 may be stopped after the traveling motor 11 is rotated in the reverse direction and the main body of the cleaning robot 1 is moved back by a predetermined amount. By doing so, the cleaning robot 1
When the moving object approaching the main body collides, the cleaning robot 1 moves back by a predetermined distance,
The impact at the time of collision is reduced. Therefore, the possibility that the cleaning robot 1 and the colliding moving object are damaged by the impact at the time of the collision can be reduced. In addition, the path of the colliding moving object is shifted, and the traveling (moving) of the colliding moving object is not hindered.

As shown in FIG. 5, the display / operation unit 1
5 may be provided with a limit amount setting unit 21 for changing the setting of the limit amount for recognizing that the main body of the cleaning robot 1 is stopped by an obstacle. This allows the user to freely change the limit amount in the above embodiment. Here, it is known that the magnitude of the load torque applied to the traveling motor 11 varies depending on the state of the floor on which the cleaning robot 1 travels. FIG. 6 is a diagram showing the magnitude of the load torque applied to the traveling motor when the floor is a carpet and when the floor is a tile. As shown in the figure, if the floor is a carpet, the normal running state (T1
-T2), the load torque applied to the traveling motor 11 is relatively large, and if the floor is a tile, the apparatus main body is stopped by an obstacle (T2 to T2).
3, T3 to T4), the load torque applied to the traveling motor 11 is relatively small. This is because the smaller the friction between the drive wheel 2 and the floor surface, the more easily the drive wheel 2 idles.

Therefore, in the case of the cleaning robot 1 used at a plurality of places, the magnitude (limit amount) of the load torque for judging that the apparatus main body is stopped by an obstacle according to the floor surface of the place to be used. Should be changed, and in the configuration shown in FIG.
Since the number 1 is provided, the limit amount can be changed to an appropriate value according to the floor on which the user travels the apparatus main body (depending on the place where the cleaning robot 1 is used). Therefore, even if the use environment of the cleaning robot 1 changes, it is possible to make the apparatus main body surely recognize that the cleaning robot 1 is stopped by the obstacle, and stop the traveling motor 11.
Thereby, the cleaning robot 1 is provided in the same manner as in the above-described embodiment.
Further, it is possible to prevent further damage to the colliding obstacle.

In the above description, the display / operation unit 15 is provided with the limit amount setting unit 21. However, as shown in FIG. 7, the state of the floor surface (for example, the frictional force between the driving wheel 2 and the floor surface) is determined. A floor sensor 22 for detection may be provided, and the control unit 10 may automatically set the limit amount based on the detection result of the floor sensor 22. In this way, the user does not feel troublesome to set the limit amount, and it is also possible to prevent a malfunction of the apparatus main body due to a mistake in setting the limit amount.

Further, the main body of the cleaning robot 1 may be provided with a structure for notifying the surrounding operation of a subsequent operation of the main body of the apparatus after the running motor 11 is stopped due to a collision or the like. For example, after stopping the traveling motor 11 on the display / operation unit 15, “Are you OK? Back once and turn right. Is displayed, the surrounding people can be notified of the subsequent operation of the apparatus main body. Thus, it is possible to notify the surrounding people of the future operation of the cleaning robot 1, without giving an anxiety to the surrounding people, and to allow the surrounding people to take a smooth action. In addition, after stopping on the display / operation unit 15, "Are you OK? Do you want to restart? May be displayed and waiting for an input as to whether or not to restart. In this case, it is possible to make the surrounding people select the future operation of the cleaning robot 1.

In the above description, a message is displayed on the display / operation unit 15 to notify the surroundings of the operation after the stoppage of the traveling motor 11 due to a collision of the apparatus main body.
As shown in FIG. 8, a voice output unit 23 may be provided in the cleaning robot 1 to notify the surroundings by voice.

When the running motor 11 is stopped and the load torque is applied to the running motor 11, the control unit 10 moves the main body by a predetermined distance in the direction in which the load torque is applied. The magnitude of the load torque applied to the traveling motor 11 is detected by the load torque detector 20.
Thus, the cleaning robot 1 in which the traveling motor 11 is stopped can be easily moved to a desired position as described below.

When the user pushes the main body forward or backward to move the cleaning robot 1 in which the main body (running motor 11) is stopped, a load torque is applied to the running motor 11 in the direction pressed by the user. When the control unit 10 detects that a load torque of a certain amount or more is applied when the traveling motor 11 is stopped, the control unit 10 moves the apparatus body by a predetermined distance. In other words, when the user pushes the cleaning robot 1 in the direction in which it is desired to move (at this time, with a force that generates a load torque of a certain amount or more), the control unit 10 moves the apparatus main body by a predetermined distance in the direction in which it is pushed. .

Further, when the control unit 10 moves the main body by a predetermined distance to stop the traveling motor 11, if the user presses the apparatus main body, the load torque is applied to the traveling motor 11 again. 10 again moves the body by a predetermined distance. Therefore, the user can easily move the apparatus main body to a desired position by keeping the cleaning robot 1 pressed.

When a moving object collides with the apparatus main body while the traveling motor 11 is stopped, a load torque is generated in the traveling motor 11, so that the control unit 10 moves the apparatus main body by a predetermined distance. Thereby, the impact due to the collision with the moving object can be reduced, and the damage to the cleaning robot 1 and the colliding moving object can be reduced.

The speed at which the apparatus main body is moved may be changed according to the magnitude of the load torque applied to the traveling motor 11. With this configuration, the user can control the moving speed of the apparatus main body by changing the magnitude of the pressing force on the apparatus main body, so that the apparatus main body can be more easily moved to a desired position.

In the above embodiment, the traveling motor 1
The traveling motor 1 is determined based on the amount of twist of the transmission shaft between
Although the magnitude of the load torque acting on the traveling motor 11 is detected, the magnitude of the load torque acting on the traveling motor 11 may be detected from the magnitude of the current flowing through the traveling motor 11 (load). The current increases as the torque increases.)

The present invention can be applied not only to the cleaning robot 1 but also to other types of self-propelled robots such as a guide robot for guiding facilities and a transport robot for transporting luggage.

[0049]

As described above, according to the present invention, whether the apparatus main body is stopped by an obstacle is recognized based on the magnitude of the load torque applied to the drive motor for running the apparatus main body. When the vehicle is stopped by an obstacle, the drive motor is stopped, so that a large load torque is not continuously applied to the drive motor for a long time. Thus, it is possible to prevent the drive motor and the drive wheels from being damaged.

When the vehicle collides with an obstacle, it moves by a predetermined distance to stop the drive motor.
The movement of the colliding object is not hindered, and the impact due to the collision is reduced, so that the damage to the apparatus body and the colliding obstacle can be reduced.

Since the magnitude of the load torque for judging that the main body has been stopped by an obstacle can be changed, the environment in which the apparatus main body is used (running) according to the state of the floor on which the main body runs. (The type of floor surface to be operated).

When the main body is stopped by an obstacle, the operation of the main body of the apparatus is notified so that the surrounding persons are not anxious.

When a load torque is applied when the drive motor is stopped, the apparatus main body is moved by a predetermined distance in the direction in which the load torque is applied, so that the apparatus main body can be easily moved to a desired position. it can.

Further, since the moving speed of the main body is changed according to the magnitude of the load torque applied at this time, the main body can be more easily moved to a desired position.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cleaning robot according to an embodiment of the present invention.

FIG. 2 is a view in the direction of arrows AA in FIG. 1;

FIG. 3 is a block diagram illustrating functions of a cleaning robot according to an embodiment of the present invention.

FIG. 4 is a graph showing a magnitude of a load torque applied to a traveling motor.

FIG. 5 is a block diagram showing functions of a cleaning robot according to another embodiment of the present invention.

FIG. 6 is a graph showing a magnitude of a load torque applied to a traveling motor when a floor is a carpet and a tile.

FIG. 7 is a block diagram showing functions of a cleaning robot according to another embodiment of the present invention.

FIG. 8 is a block diagram showing functions of a cleaning robot according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1-cleaning robot 10-control unit 11-running motor 14-ultrasonic sensor 15-display / operation unit 20-load torque detection unit 21-limit amount setting unit 22-floor surface sensor 23-voice output unit

Claims (6)

[Claims] 1. A self-contained traveling robot provided with traveling means for causing an apparatus body to travel independently by a drive motor, wherein: a load torque detection means for detecting a magnitude of a load torque applied to the drive motor; A drive motor stopping means for stopping the drive motor when the magnitude of the load torque detected by the means exceeds a predetermined limit. 2. The self-propelled traveling robot according to claim 1, wherein the drive motor stopping means stops the drive motor after moving the main body by a predetermined distance by the traveling means. 3. The self-propelled robot according to claim 1, further comprising limit amount changing means for changing the limit amount. 4. The self-contained traveling type according to claim 1, further comprising an informing means for informing surroundings of a subsequent operation of the apparatus main body when the driving motor is stopped by the driving motor stopping means. robot. 5. A self-contained traveling robot provided with a traveling means for causing an apparatus body to travel independently by a drive motor, wherein a load torque detecting means for detecting a magnitude of a load torque applied to the drive motor, and a stop of the apparatus body. And when the magnitude of the load torque detected by the load torque detection means exceeds a certain amount, movement control means for moving the apparatus body by a predetermined distance in a direction in which the load torque is applied by the traveling means. Self-contained traveling robot equipped with. 6. The self-propelled robot according to claim 5, wherein the movement control means includes means for controlling a movement speed of the apparatus body based on a magnitude of the load torque detected by the load torque detection means.