JP7295654B2 - self-propelled robot - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is suitable for application to self-propelled robots capable of autonomous movement within facilities such as shopping malls and airports.

In recent years, autonomously mobile robots such as automatic cleaning robots have been equipped with SLAM (Simultaneous Localization and Analysis), which estimates its own position with respect to the external environment and simultaneously creates an environmental map.
Mapping) technology has been proposed.

As an autonomous mobile robot using this SLAM technology, an environment that expresses the three-dimensional position of an object existing in real space while estimating its own position with high accuracy using a range sensor such as a laser range sensor. By dynamically generating a map, it is common to specify its own movement route and move autonomously within the environment.

Self-propelled robots that move autonomously are controlled so that their speed is relatively slow to avoid crowds when traveling in the facility, but there are times when there are no users, such as when the facility is closed. Now, it's desirable to drive as fast as possible to get where you need to be.

Conventionally, as a device for maintaining the posture of a mobile body and preventing it from overturning, there has been known a device in which a driven wheel and a support member are provided at the periphery of the mobile body. For example, when the inclination and the direction of inclination with respect to the horizontal plane of the mobile body exceeds a reference value, the attitude of the mobile body is determined by extending the support member from the mobile body to the road surface and continuing to drive it downward until it falls below the reference value. A device capable of holding and preventing overturning is disclosed (see Patent Document 1).

In addition, the ZMP (Zero Moment Point), which is the intersection point where the resultant force of gravity and inertial force intersects with the ground surface, is measured before the start of overturning to evaluate overturning safety, thereby preventing overturning. A mobile robot has been proposed (see Patent Document 2).

In addition, the equipment main body is provided with anti-toppling legs that can protrude, and according to whether or not the equipment main body is tilted, the rotation of the weight amplified and transmitted via the transmission mechanism prevents the equipment main body from overturning. A fall prevention device is disclosed which is designed to project or retract the foot (Patent Document 3).

In addition, a pair of fall prevention legs are provided on the front and back of the two-wheeled inverted robot body to prevent it from overturning. Disclosed is a two-wheeled inverted robot capable of stably preventing overturning by making the anti-overturning legs contact the ground perpendicularly to the ground plane even when the inversion control cannot be performed (Patent Reference 4).

JP-A-2006-53731 JP-A-2008-12642 JP 2009-291487 A JP 2013-163457 A

By the way, in the above-mentioned Patent Documents 1, 3 and 4, the driven wheels and support members are projected from the peripheral portion of the main body in accordance with the inclination of the moving body to hold the attitude of the moving body and prevent the overturning. , there is a problem that a mechanism for preventing overturning is required, the number of parts increases, and the configuration becomes complicated.

Further, in the above-mentioned Patent Document 2, the mobile robot moves forward the fixed strut itself that supports the arm connecting portion, and lowers the arm connecting portion from the rotation axis of the fixed strut so that the position of the center of gravity is lowered. Although changed, the forward and backward movement of the fixed support and the vertical movement of the arm connecting portion are merely operations within the installation frame of the traveling portion that holds the pair of wheels.

For this reason, it cannot be applied to a mobile robot having a member that protrudes outward beyond the installation frame of the base portion that drives and holds a pair of wheels. However, there remains the difficulty of adjusting the position of the center of gravity in consideration of the movable state of the robot.

The present invention has been made in consideration of the above points, and proposes a self-propelled robot capable of ensuring dynamic stability during travel without providing a dedicated member.

In order to solve such problems, the present invention provides a self-propelled robot that travels on a floor autonomously or in response to an external operation, in which a pair of drive wheels are driven to rotate simultaneously or independently to move the robot body in a desired direction. and an end of an arm having at least one or more joint mechanisms, and is rotatable integrally with the arm about the vertical direction as a center of rotation with respect to the travel drive. an arm support section connected to the upper stage of the travel drive section; and a center-of-gravity position calculation section that calculates the center-of-gravity position of the robot body based on the rotational position of the arm support section with respect to the travel drive section and the attitude state of the arm section. , an inclination angle sensor for detecting the inclination angle of the travel drive unit with respect to the floor surface, an acceleration sensor for detecting the two-axis combined acceleration of the arm support unit whose rotation center is the roll axis and the pitch axis with respect to the travel direction, and the travel drive unit. and a control unit for driving and controlling the arm support unit, respectively, wherein the control unit controls the rotation position of the arm support unit and the arm unit based on the detection results of the tilt angle sensor and the acceleration sensor when the traveling drive unit is driven. is changed and adjusted so as to correct the eccentricity between the position of the center of gravity of the robot body and the center of rotation of the arm support, while maintaining the dynamic stability of the robot body.

In this way, the self-propelled robot adjusts the rotational position of the arm support and the posture of the arm so as to change the position of the center of gravity of the robot body so that the dynamic stability of the robot body is always maintained during running. As a result, there is no need to provide a separate member for preventing overturning, and the arm portion always abuts against the floor surface, thereby facilitating recovery from overturning.

Further, in the present invention, the arm portion of the arm support portion is composed of a multi -joint mechanism having multiple degrees of freedom. is set as a default position for providing regularity to changes in the center of gravity position of the robot body, and the eccentricity about the vertical rotation axis is set to a predetermined eccentricity determined by the default position. made it

As a result, when the self-propelled robot rotates the arm support section with respect to the traveling drive section during normal traveling, the arm section is set to the default position, and the position of the center of gravity of the robot body is actively adjusted. By providing regularity to the change, it is possible to reduce the computational load for adjusting the change in the position of the center of gravity.

Further, in the present invention, the maximum length of the arm protruding from the arm support in the direction parallel to the floor is set so as to prevent the position of the center of gravity of the robot body from becoming extremely large. Each joint mechanism is bent or extended in a desired state so as to be within a predetermined length range. As a result, even when the self-propelled robot is in a state of gripping an article or the like with the end effector of the arm during normal travel, it is limited to within a predetermined length outward from the installation frame of the travel drive unit. As a result, it is possible to prevent an extremely large change in the position of the center of gravity of the robot main body, and to allow a specific joint portion of the arm to face the floor when tilted.

Further, in the present invention, the control section controls the arm movement so that the arm section comes into contact with the floor when the overturning moment acting on the robot main body exceeds a predetermined level based on the detection results of the tilt angle sensor and the acceleration sensor. The supporting part is made to rotate. As a result, when the self-propelled robot falls, the robot main body does not directly collide with the floor surface, and can be brought into contact with the floor surface from a specific joint portion of the arm.

Furthermore, in the present invention, the control unit moves a specific joint portion so as to cushion the collision when the arm contacts the floor surface. As a result, in the self-propelled robot, when a specific joint part of the arm contacts the floor surface, the robot body does not directly receive the impact, and each joint part including the base of the arm part absorbs the impact. It is possible to reduce the impact damage received by the robot body.

Further, in the present invention, the control section adjusts the rotational position of the arm support section for the robot main body that is in an overturned state, and moves the joints of the arm section in a state in which the tip of the arm section is in contact with the floor surface. The pair of drive wheels of the traveling drive unit are returned to the return state in which they contact the floor surface while being moved.

As a result, since the arm of the self-propelled robot is in contact with the floor when recovering from the overturned state, the arm support section is driven to extend the joints of the arm, thereby enabling comparison. It is possible to return to the original standing position as it is in a short period of time.

As described above, according to the present invention, it is possible to realize a self-propelled robot capable of maintaining stability during travel.

1 is an external view showing the overall configuration of a self-propelled robot according to this embodiment; FIG. 1 is an external view showing the overall configuration of a self-propelled robot according to this embodiment; FIG. FIG. 3 is a schematic diagram showing the configuration of the bottom side of the self-propelled robot according to the present embodiment; 4 is a schematic exploded view showing the configuration of an arm support; FIG. 1 is a block diagram showing the configuration of a control system of a self-propelled robot; FIG. FIG. 4 is a top view for explaining a rotating state of an arm support; FIG. 10 is a front view for explaining posture stabilization behavior of the self-propelled robot when it is tilted; FIG. 10 is a front view for explaining the shock absorbing and avoiding behavior of the self-propelled robot when it falls. FIG. 10 is a front view for explaining the operation of the arm portion when the self-propelled robot recovers from overturning;

An embodiment of the present invention will now be described in detail with reference to the drawings.

(1) Configuration of self-propelled robot according to the present embodiment FIGS. 1 to 3 show a self-propelled robot 1 according to the present embodiment as a whole. The self-propelled robot 1 is a two-wheel-drive mobile body that runs on the floor autonomously or in response to external operation, and rotates a pair of drive wheels 5a and 5b simultaneously or independently to rotate the robot body as desired. A traveling base portion (traveling drive portion) 2 for traveling in a direction, and an end portion of an arm portion 6 having at least one or more joint mechanisms, and are integrated with the arm portion 6 with the vertical direction as the center of rotation. An arm supporting portion 3 is connected to the upper stage of the traveling base portion 2 so as to be rotatable with respect to the traveling base portion 2 .

As shown in the bottom view of FIG. 3, the traveling base portion 2 is provided with a pair of omni wheels 7a and 7b as front wheels, and an auxiliary wheel at the center of the rear end between the pair of rear driving wheels 5a and 5b. A wheel 8 is provided. As a result, the self-propelled robot 1 can travel in the front-rear direction by rotating the pair of drive wheels 5a and 5b simultaneously while the travel base 2 rotates and moves the pair of drive wheels 5a and 5b independently. Then, the omniwheels 7a and 7b can follow and travel left and right.

That is, the pair of drive wheels 5a and 5b are independently rotationally driven by drive motors (for example, in-wheel motors) 9a and 9b (see FIG. 5, which will be described later). The vehicle moves backward and travels to the right or left while moving forward by giving a difference to the forward rotation angles of the drive wheels 5a and 5b. Further, by rotating the driving wheels 5a and 5b in mutually opposite directions, the self-propelled robot 1 spins, that is, changes direction at that position.

The arm support portion 3 supports the end portion of the arm portion 6 having at least one or more joint mechanisms, and rotates integrally with the arm portion 6 with respect to the traveling base portion 2 about the vertical direction as the center of rotation. It is freely connected to the upper stage of the traveling base portion 2 .

A tray 10 is fixed on the upper part of the traveling base 2 at a position close to the connection part of the arm support 3, and an article or the like is placed using the arm 6 of the arm support 3 as necessary. It is made possible.

A laser range sensor 11 and an RGB-D sensor 12 capable of three-dimensional scanning are provided on the front side (moving direction side) of the traveling base portion 2, and a plurality of sensors are provided at predetermined intervals so as to surround the upper side in all directions. A 3D distance image sensor 13 is arranged to detect obstacles obliquely forward and left and right.

Specifically, the laser range sensor 11 irradiates an object (obstacle) viewed from the installation position, receives the reflected light, and calculates the distance. By measuring the distance at regular angular intervals, it is possible to obtain fan-shaped distance information on a plane within a maximum range of 30 m and an angle of 240 degrees.

In addition to the RGB color camera function, the RGB-D sensor 12 has a depth sensor capable of measuring the distance to an object (obstacle) seen from the camera, and can perform three-dimensional scanning of the object. . The depth sensor consists of an infrared sensor that images an object with a single pattern of structured light projected onto it and uses the parameters to calculate the depth of each point on the image by triangulation.

For example, when kinect (registered trademark of Microsoft Corporation) is applied as the RGB-D sensor 12, it is possible to photograph a horizontal field of view of 57 degrees, a vertical field of view of 43 degrees, and a sensor range of 1.2 m to 3.5 m. , RGB images of 640×480 pixels and depth images of 320×240 pixels, both of which can be acquired at 30 frames/second.

The reason why the RGB-D sensor 12 is installed at the center of the upper part of the arm support part 3 is that the vertical field of view cannot be secured in the traveling base part 2 which is almost close to the floor surface, and a height of 0.6m to 1.8m from the floor surface is secured. Is required.

The 3D distance image sensor 13 irradiates an LED pulse, measures the arrival time of reflected light from the object on a pixel-by-pixel basis, and simultaneously superimposes the acquired image information to calculate the distance information to the object on a pixel-by-pixel basis. do. Since the 3D range image sensor 13 has higher detection accuracy than the RGB-D sensor 12 and has a wider viewing angle than the laser range sensor 11, it is necessary as a complementary sensor for outdoor use.

If, for example, Pixel Soleil (trade name of Nippon Signal Co., Ltd.) is applied as the 3D distance image sensor 13, it is possible to photograph a horizontal field of view of 72 degrees, a vertical field of view of 72 degrees, and a sensor range of 0.3 m to 4.0 m. is.

The self-propelled robot 1 of the present invention uses a laser range sensor 11, an RGB-D sensor 12, and a 3D range image sensor 13 to estimate its own position with respect to the external environment and at the same time create an environment map. Localization and Mapping) technology is being implemented.

The self-propelled robot 1 using this SLAM technology estimates its own position with high accuracy and dynamically generates an environment map representing the three-dimensional position of objects existing in real space. It is possible to specify the movement route of the robot and move autonomously in the environment.

At the upper end of the arm support section 3, an imaging camera 14 having a plurality of ultra-wide-angle lenses is provided so that the space of the self-propelled robot 1 in all directions (360 degrees) can be imaged. there is Furthermore, a sound collecting microphone and a speaker (both not shown) are mounted on the central upper portion of the arm support portion 3, and collects sounds in the surrounding environment, and emits utterances and warning sounds as necessary. ing.

(2) Structure of Arm Portion in Arm Support Portion As shown in FIG. A shoulder upper arm portion 21 rotatably connected in a direction perpendicular to the rotation direction, a forearm portion 22 rotatably connected in the same direction as the shoulder upper arm portion 21, and a rotation direction perpendicular to the forearm portion 22. and a hand portion (end effector) 24 rotatably connected with a rotation axis perpendicular to the turning direction of the wrist portion 23 .

That is, the arm support part 3 has a multi-joint arm part 6 (shoulder upper arm part, forearm part, wrist part, hand part) having four degrees of freedom with respect to the support body part 20. Each axis (A axis to D axis) are connected rotatably about the center of rotation.

Specifically, the supporting body 20 and the shoulder upper arm 21 are connected so as to be rotatable about the A axis, and the shoulder upper arm 21 and the forearm 22 are connected so as to be rotatable about the B axis. 22 and the wrist portion 23 are connected so as to be rotatable about the C axis, and the wrist portion 23 and the hand portion 24 are connected so as to be rotatable about the D axis.

The joints between the support main body 20 and the shoulder upper arm 21, the joints between the shoulder upper arm 21 and the forearm 22, the joints between the forearm 22 and the wrist 23, and the joints between the wrist 23 and the hand 24, respectively. For example, an actuator composed of a DC servomotor is provided and is rotationally driven via a transmission mechanism (not shown).

The hand portion 24 is, for example, an end effector having a gripping function with four fingers, and an actuator provided therein is driven and controlled in conjunction with the operation of the arm portion 6 (excluding the hand portion) to open or close. It is designed to act.

The arm support portion 3 is bent so that the hand portion 24 of the arm portion 6 is housed in the support body portion 20 during normal running, and the joint portion between the shoulder upper arm portion 21 and the forearm portion 22 protrudes outward. , the default position is set such that the wrist axis (D axis) intersects the extension of the shoulder joint axis (A axis).

(3) Internal Configuration of Self-propelled Robot FIG. The integrated control unit 30 is mainly composed of a microcomputer, and includes a travel control unit 31 that controls the entire vehicle, a target travel route control unit 32 that stores travel route information, and an operation control unit 33 that controls the drive system.

The travel control unit 31 stores travel route information set in advance from the target travel route control unit 32, and each detection signal from the laser range sensor 11, the RGB-D sensor 12, and the 3D range image sensor 13. While simultaneously estimating the self-position and constructing the environment map based on the information, it judges whether the travel route is suitable or not, and whether there are any obstacles.

For example, when the self-propelled robot 1 on the office floor travels along the taught travel route, it is determined whether or not it will come into contact with a travel obstacle such as a wall surface or just in front of a staircase. Change the driving route in the direction along the route.

The travel control unit 31 sends the determined travel route information to the operation control unit 33, and the operation control unit 33 controls the left and right motor drivers 34a and 34b according to the travel route information to rotate the drive motors 5a and 5b. to control.

Actually, the self-propelled robot 1 uses the SLAM technology described above to automatically create an environmental map of the target area desired by the user.

Specifically, the self-propelled robot 1 sets a local map on a grid divided by a two-dimensional grid as an area indicating the movement environment based on distance information and angle information from the object obtained from the laser range sensor 11. As you do so, create an environmental map that represents the entire desired target area.

At the same time, based on the rotation angle read from the encoders (not shown) corresponding to the pair of driving wheels 5a and 5b of the self-propelled robot 1, the travel distance of the self-propelled robot 1 is calculated, and the next whereabouts map and the current time are calculated. The position is estimated from the matching with the environment map created up to this point and the distance traveled by the aircraft.

The travel control unit 31 drives and controls the travel base unit 2 and the arm support unit 3, respectively, and controls the movement of the robot main body based on the rotational position of the arm support unit 3 with respect to the travel base unit 2 and the attitude state of the arm unit 6. Calculate the center of gravity position.

In the present embodiment, the traveling base 2 includes an inclination angle sensor 35 for detecting an inclination angle with respect to the floor surface, and a two-axis synthetic acceleration of the arm support 3 whose rotation center is the roll axis and the pitch axis with respect to the traveling direction. and an acceleration sensor 36 for detecting

When the traveling base portion 2 is driven, the traveling control portion 31 adjusts the rotational position of the arm support portion 3 and the attitude state of the arm portion 6 to the center of gravity of the robot main body based on the detection results of the tilt angle sensor 35 and the acceleration sensor 36 . The dynamic stability of the robot body can be maintained by adjusting the changing position.

The self-propelled robot 1 also includes a communication unit 37 that wirelessly communicates with an external information input device (not shown). Receives data indicating the content of the operation instruction from.

Further, the self-propelled robot 1 incorporates a relatively large-capacity drive battery 38 consisting of a secondary battery or a capacitor. By conductively connecting the charging terminal of 38, it becomes possible to supply power supplied from a commercial power supply to the drive battery 38 via the power supply terminal to charge the battery.

(4) Operation of Self-Propelled Robot When Overturned and Returned In self-propelled robot 1 of the present embodiment, during normal travel, travel controller 31 controls tilt angle sensor 35 when travel base 2 is driven. And based on the detection result of the acceleration sensor 36, the dynamic stability of the robot body is adjusted while adjusting the rotational position of the arm support part 3 and the attitude state of the arm part 6 so as to change the position of the center of gravity of the robot body. maintain.

In this manner, the self-propelled robot 1 changes the rotation position of the arm support 3 and the posture of the arm 6 so as to change the center of gravity of the robot main body so as to maintain the dynamic stability of the robot main body during running. , it is not necessary to provide a separate member for preventing overturning, and since the arm portion 6 always abuts against the floor surface, it is possible to facilitate overturn recovery.

At that time, in the self-propelled robot 1 , the travel control unit 31 controls the rotation of the arm support unit 3 so as to achieve a predetermined eccentricity around the vertical rotation axis when the arm support unit 3 rotates with respect to the travel base unit 2 . Then, each joint mechanism of the arm portion 6 is set to the default position.

In addition, when the self-propelled robot 1 rotates the arm support part 3 with respect to the travel base part 2 during normal travel, the arm part 6 is set to the default position, and the robot main body is actively moved. By providing regularity to the change in the position of the center of gravity, it is possible to reduce the computational load for adjusting the change in the position of the center of gravity.

For example, as shown in FIGS. 6(A) to 6(C), the self-propelled robot 1 positions the arm support part 3 with respect to the traveling base part 2 in the traveling direction (FIG. 6(A)). , based on the position of the center of gravity at this time. Subsequently, when the arm supporting portion 3 is rotated to the right (FIG. 6B) with respect to the traveling base portion 2, the center of gravity moves to the right from the reference. On the other hand, when the arm supporting portion 3 is rotated in the left turning direction (FIG. 6(C)) with respect to the traveling base portion 2, the center of gravity moves leftward from the reference.

Further, in the self-propelled robot 1, each joint mechanism (joint part) of the arm part 6 is arranged in a desired state so that the maximum length of the arm part 6 protruding from the arm support part 3 in the direction parallel to the floor is within a predetermined length range. flexion or extension.

As a result, even when the self-propelled robot 1 is in a state of gripping an article or the like with the hand portion (end effector) 24 of the arm portion 6 during normal travel, the self-propelled robot 1 can move a predetermined distance outward from the installation frame of the travel base portion 2 . By limiting the length within the length, the change in the center of gravity position of the robot main body is prevented from becoming extremely large, and the joint portion between the shoulder upper arm 21 and the forearm 22 is opposed to the floor surface when tilted. It is possible to

Further, in the self-propelled robot 1 shown in FIG. 7(A), the travel control unit 31 controls the time point when the overturning moment acting on the robot main body exceeds a predetermined level based on the detection results of the tilt angle sensor 35 and the acceleration sensor 36. Then, the arm supporting portion 3 is rotated so that the joint portion between the shoulder upper arm portion 21 and the forearm portion 22 of the arm portion 6 contacts the floor (FIG. 7(B)).

As a result, when the self-propelled robot 1 falls, the robot main body does not directly collide with the floor surface, and the joint portion between the shoulder upper arm portion 21 and the forearm portion 22 of the arm portion 6 can be brought into contact with the floor surface. becomes.

Furthermore, in the self-propelled robot 1 shown in FIG. 8(A), the travel control unit 31 controls a specific joint mechanism to cushion the collision when the arm unit 6 contacts the floor surface (FIG. 8(B)). is movable (Fig. 8(C)). As a result, the self-propelled robot 1 does not directly receive an impact when the joint portion of the arm portion 6 between the shoulder upper arm portion 21 and the forearm portion 22 abuts on the floor surface, and the arm portion 6 does not directly receive the impact. It can be absorbed by the joint parts including the root, and it is possible to reduce the impact damage received by the robot body.

Further, in the self-propelled robot 1 , the travel control unit 31 adjusts the rotational position of the arm support unit 3 with respect to the travel base unit 2 and moves the tip of the arm unit 6 with respect to the robot main body in the overturned state ( FIG. 9A ). are in contact with the floor surface, the pair of drive wheels 5a and 5b of the traveling base portion 2 are returned to the return state in contact with the floor surface while moving each joint of the arm portion 6 (Fig. 9 (B) and (C)).

As a result, when the self-propelled robot 1 recovers from a fallen state, since the arm portion 6 is in contact with the floor surface, the arm support portion 3 is driven to extend each joint portion of the arm portion 6. As a result, it is possible to restore the original standing position in a relatively short period of time.

(5) Other Embodiments In the above-described embodiments, the self-propelled robot 1 has been described as a two-wheel-drive mobile body that can travel autonomously or in response to an external operation. The present invention is not limited to this, and may be a four-wheel drive type, and as long as it can move while supporting the arm portion 6, various types of drive methods, number of wheels, etc. may be applied. Also, although the pair of front wheels are each made of omni-holes, other than that, various running mechanisms such as casters and caterpillars may be applied.

Further, in the above-described embodiment, the arm portion 6 (shoulder upper arm portion 21, forearm portion 22, wrist portion 23, hand portion 24) having a multi-joint structure having four degrees of freedom has each axis (A axis to D-axis) has been described above, but the present invention is not limited to this. structure may be applied.

DESCRIPTION OF SYMBOLS 1... Self-propelled robot, 2... Travel base part (travel drive part), 3... Arm support part, 5a, 5b... Drive wheel, 6... Arm part, 7a, 7b... Omni wheel, 8... Auxiliary wheel, 9a, 9b... drive motor, 10... tray, 11... laser range sensor, 12... RGB-D sensor, 13... 3D range image sensor, 14... imaging camera, 20... support body, 21... shoulder upper arm, 22... forearm , 23... wrist part, 24... hand part, 30... integrated control part, 31... travel control part, 32... target travel route storage part, 33... operation control part, 34a, 34b... motor driver, 35... inclination angle sensor, 36... acceleration sensor, 37... communication unit, 38... drive battery.

Claims (4)

In a self-propelled robot that runs on the floor autonomously or in response to an external operation,
a travel drive unit that drives a pair of drive wheels to rotate simultaneously or independently to travel the robot body in a desired direction;
Supporting the end portion of an arm portion having at least one or more joint mechanisms, and rotating freely with respect to the travel drive portion integrally with the arm portion with the vertical direction as the center of rotation. an arm support connected to the upper stage;
a center-of-gravity position calculation unit that calculates the center-of-gravity position of the robot main body based on the rotational position of the arm support unit with respect to the traveling drive unit and the posture state of the arm unit;
an inclination angle sensor that detects an inclination angle of the traveling drive unit with respect to the floor surface;
an acceleration sensor for detecting a combined two-axis acceleration of the arm supporting portion whose rotation centers are the roll axis and the pitch axis with respect to the running direction;
a control unit that drives and controls the travel drive unit and the arm support unit, wherein the control unit moves the arm unit to the robot main body when the arm support unit rotates with respect to the travel drive unit. Set it to the default position to provide regularity in the change of the center of gravity position,
When the travel drive unit is driven, the position of the center of gravity of the robot body and the arm support are determined based on the relationship between the tilt angle detected by the tilt angle sensor and the two-axis synthetic acceleration detected by the acceleration sensor. dynamic stability of the robot main body is maintained while changing and adjusting the rotation position of the arm support so as to correct the eccentricity of the arm support from the center of the vertical rotation axis of the arm. self-propelled robot. Based on the detection results of the tilt angle sensor and the acceleration sensor, the control unit controls the arm so that the arm contacts the floor when a tipping moment acting on the robot main body exceeds a predetermined level. 2. The self-propelled robot according to claim 1 , wherein the arm support portion is rotated. The self-propelled robot according to claim 1 or 2, wherein the control section moves a specific joint mechanism so as to cushion a collision when the arm section contacts the floor surface. The control unit adjusts the rotational position of the arm support unit to move each joint of the arm unit in a state in which the tip of the arm unit is in contact with the floor surface, with respect to the robot main body that is in an overturned state. 4. The self-propelled robot according to claim 3 , wherein the pair of drive wheels of the travel drive unit are returned to a return state in which the pair of drive wheels contact the floor surface.

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