JP6587814B2 - Autonomous robot - Google Patents

Description

  The present invention relates to an autonomous traveling robot, and relates to a technique for preventing a fall due to inertial force or external force when controlling movement and enabling stable traveling on a raised terrain or a depressed terrain.

  In recent years, various robots sharing an activity space with humans have been announced. In addition, many robots have been proposed that have the same height as humans when sharing an activity space with humans. In the case of such a robot having a height similar to that of a human, the robot is often designed to have a high center of gravity. As a result, the robot is likely to receive a strong moment of inertia because it acts on the center of gravity where the inertial force is high during sudden acceleration or sudden stop. Therefore, the risk of falling is high and stable running may be difficult.

  In view of this, there has been proposed a robot that is provided with a buffer mechanism that relaxes the inertial force that occurs during position control and that can stably run while reducing the risk of falling. Specifically, for example, an autonomous traveling robot disclosed in Patent Document 1 can be given.

  In the autonomous mobile robot 100 disclosed in Patent Document 1, as shown in FIG. 15, the upper structure portion is compared with the housing base plate 111 formed of a plane provided on the upper surface of the moving mechanism portion 110 that is a drive portion. A casing 120 is provided so as to be movable in a plane via the linear guide 101. When the autonomous mobile robot 100 suddenly starts or stops, the buffer member 121 or 121 absorbs the inertial force, thereby preventing the autonomous mobile robot 100 from falling.

JP 2006-150537 A (released on June 15, 2006)

  However, the autonomous traveling robot 100 disclosed in the above-described conventional Patent Document 1 has the following problems.

  That is, in the configuration of the autonomous traveling robot 100, a configuration in which the drive unit and the upper structure are divided is necessary for the overturn control. For this reason, many sensors are used in the autonomous traveling robot to recognize the surrounding environment. However, in the configuration of the autonomous traveling robot 100, the information sensed by the upper and lower divisions of the drive unit and the self-position information are not recognized. Such a problem may occur.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an autonomous traveling robot that can prevent overturning in at least one of the front and rear directions without dividing the upper structure and the drive unit. It is to provide.

  In order to solve the above problems, an autonomous mobile robot according to one aspect of the present invention is rotatably supported on the base by a rotary shaft on one side of the base and the front-rear direction on the lower side of the base, and On the other side in the front-rear direction on the lower side of the base body, a drive part support member supported by the base body so as to be vertically extendable, a rotatable drive wheel mounted on the drive part support member, and the drive part support member A drive unit including a power source that is mounted on the drive wheel and drives the drive wheel; and a rotatable other auxiliary wheel supported on a base body at least on the other side in the front-rear direction with respect to the drive wheel. The combined center of gravity of the drive unit support member is present at a position lower than the rotational axis of the drive unit support member.

  According to one aspect of the present invention, there is an effect of providing an autonomous traveling robot that can prevent a fall in at least one of the front and rear directions without dividing the superstructure and the drive unit.

It is a side view which shows the structure of the autonomous running robot in Embodiment 1 of this invention. It is a top view which shows the structure of the said autonomous traveling robot. It is a bottom view which shows the structure of the said autonomous running robot. It is a schematic diagram which shows the principle of the fall control of the said autonomous traveling robot. When the inclination of the trailing arm of the autonomous mobile robot (5 °, 10 °) in a graph showing the relationship between the displacement [Delta] X _u of the radius R and the drive wheel of the drive wheel. When the inclination of the trailing arm of the autonomous mobile robot (5 °, 10 °) in a graph showing the relationship between the displacement [Delta] X _u of radius r and the drive wheels of the rear driven wheels. When the inclination of the trailing arm of the autonomous mobile robot (5 °, 10 °) in a graph showing the relationship between the trailing arm and the height h _t and displacement [Delta] X _u of the drive wheels. When the trailing arm of the autonomous mobile robot is tilted (5 °, 10 °), the relationship between the horizontal distance L _c between the shaft that is the rotation center of the trailing arm and the drive wheel axis and the displacement ΔX _{u of the} drive wheel is It is a graph to show. When the inclination of the trailing arm of the autonomous mobile robot (5 °, 10 °) in a graph showing the relationship between the front-rear direction and the length L _f and the displacement [Delta] X _u of the driving wheels of the frame. It is a side view which shows the structure of the autonomous running robot 1 in Embodiment 2 of this invention. It is a side view which shows the structure of the autonomous running robot in Embodiment 3 of this invention. It is a side view which shows the structure of the autonomous running robot in Embodiment 4 of this invention. It is an autonomous traveling robot in Embodiment 5 of this invention, Comprising: It is a side view which shows the principle for aiming at the improvement of driving | running | working stability in depression terrain. It is an autonomous traveling robot in Embodiment 5 of this invention, Comprising: It is a side view which shows the principle for aiming at the improvement of driving | running | working stability in uplifting terrain. It is side surface sectional drawing which shows the structure of the conventional autonomous running robot.

[Embodiment 1]
One embodiment of the present invention is described below with reference to FIGS.

  The configuration of the autonomous mobile robot according to the present embodiment will be described with reference to FIGS. FIG. 1 is a side view showing the configuration of the autonomous mobile robot 1 of the present embodiment. FIG. 2 is a plan view showing the configuration of the autonomous mobile robot 1 of the present embodiment. FIG. 3 is a bottom view showing the configuration of the autonomous mobile robot 1 of the present embodiment. In FIGS. 1 to 3, the right side of each figure is described as the front.

  As shown in FIGS. 1 to 3, the autonomous mobile robot 1 of the present embodiment includes a welded frame 10 as a base body and a shaft holder 11 that hangs down from a front portion as one side of the frame 10 in the front-rear direction. The other end of a compression spring 21 is attached as an elastic member that is rotatably provided on a shaft 12 as a rotating shaft formed on the rear side and is fixed to the frame 10 at the rear side as the other side in the front-rear direction of the frame 10. Trailing arms 20 and 20 as a pair of driving unit support members, driving wheels 24 and 24 connected to the trailing arms 20 and 20, respectively, and auxiliary wheels connected to the frame 10 before and after the frame 10 A pair of front driven wheels 13 and a pair of rear driven wheels 14 are provided. In this description, when a pair of components are represented using symbols, the same symbols are placed side by side with “·” in between. As a result, the autonomous mobile robot 1 of the present embodiment has a total of six wheels.

  That is, the shaft holder 11 is suspended and coupled to the rear surface, that is, the lower side surface of the front portion of the frame 10. A shaft holder hole 11a is formed in the shaft holder 11. A shaft 12 that passes through a trailing arm hole (not shown) of the trailing arms 20 and 20 is provided through the shaft holder hole 11a. For this reason, the trailing arm hole (not shown) and the shaft holder hole 11a are arranged at coaxial positions. As a result, the shaft holder 11 holds the shaft 12, and the shaft 12 holds a trailing arm hole (not shown).

  Further, the shaft 12 is disposed so as to be perpendicular to a plane formed by the traveling direction of the autonomous mobile robot 1 and the vertical direction. With this configuration, the trailing arms 20 and 20 can rotate around the shaft 12 with the shaft 12 as a rotation axis.

  The trailing arms 20 and 20 extend rearward of the shaft 12 with respect to the traveling direction of the autonomous mobile robot 1.

  The rear portions of the trailing arms 20 and 20 are coupled to a rod 22 coupled to the frame 10. The rod 22 is coupled so that the lower end thereof is loosely fitted into a long hole 20a drilled in the trailing arms 20 and 20, and at the upper portion, the rod 22 is inserted into a rod hole 10a drilled in the frame 10. It is penetrated in the loose fit state. A clasp 22a is fixed to the upper end of the rod 22, and a stopper 22b is also fixed to the lower end.

  A compression spring 21 is provided between the frame 10 and the trailing arm 20 of the rod 22 so as to surround the outer periphery of the rod 22. The compression spring 21 applies an elastic force to the trailing end of the trailing arm 20 in a vertically downward direction. As a result, the left and right trailing arms 20 and 20 are configured to swing and rotate with the shaft 12 as a rotation axis and the rod 22 as a guide.

  Next, a driving wheel mounting portion 23 is attached to the trailing arm 20 at the center of the trailing arm 20, and a driving wheel mounting portion hole 23 a formed in the driving wheel mounting portion 23 is drilled. It is installed. A drive wheel shaft 24a fixed to the drive wheel 24 is loosely fitted in the drive wheel mounting portion hole 23a. The length of the drive wheel shaft 24 a is the same as the length of the shaft 12.

  A motor 25 is mounted on the upper side of the drive wheel mounting portion 23 as a power source for rotating the drive wheel 24. The drive shaft of the motor 25 is connected to the drive wheel shaft 24a.

  With the above configuration, the trailing arm 20 supports the motor 25, and the motor 25 supports the drive wheel shaft 24a.

  In the present embodiment, the center of gravity G of the combined gravity W of the left and right trailing arms 20 and 20, the drive wheels 24 and the motor 25 as a whole is lower than the height of the shaft 12 which is the rotation center of the trailing arms 20 and 20. It is arranged at the position.

  On the other hand, the front driven wheels 13 and 13 as a pair of one side auxiliary wheels and the rear driven wheels 14 and 14 as the other side auxiliary wheels are supported by the frame 10 at the front and rear of the drive wheel 24, respectively. Is provided. That is, the front driven wheel 13 and the rear driven wheel 14 rotate freely about an axis parallel to the horizontal plane, and can freely come into contact with the ground as the autonomous mobile robot 1 moves. It comes to move.

  Further, as shown in FIG. 3, the front driven wheel 13 and the rear driven wheel 14 have their horizontal rotation centers driven by the left and right drive wheels 24 and 24 when the trailing arms 20 and 20 take the basic posture. It arrange | positions on the circle centering on the midpoint P of the ring axis 24a. With this configuration, stable running on raised terrain and depressed terrain is possible.

  In the autonomous traveling robot 1 of the present embodiment, it is possible to suppress the fall with a simple configuration by providing the above configuration, and in particular, when the autonomous traveling robot 1 is started, accelerated, and in the traveling direction. When an external force is applied backward, it is possible to suppress the fall.

  The principle of the overturning suppression of the autonomous traveling robot 1 having the above configuration will be described with reference to FIG. FIG. 4 is a schematic diagram showing the principle of the overturning suppression of the autonomous mobile robot 1.

  Here, as shown in FIG. 4, for example, when the autonomous mobile robot 1 starts, the front side of the frame 10 is lifted when the drive wheel 24 moves forward, that is, slightly moves rightward in FIG. It is assumed that the frame 10 rotates counterclockwise around the ground contact point 14b to the ground. That is, when the autonomous mobile robot 1 starts, the frame 10 tries to stop according to the law of inertia even if the drive wheel 24 moves forward, so the frame 10 is counterclockwise around the ground contact point 14b to the ground of the rear driven wheel 14. Rotate around.

  At this time, in this embodiment, it is assumed that the trailing arm 20 rotates counterclockwise by the inclination angle η (°) about the ground contact point 14 b of the rear driven wheel 14 as the frame 10 rotates.

Further, in this embodiment, as the state at this time, apparently, the drive wheel 24 is advanced by a horizontal distance [Delta] X _u, the position of the ground point 14b of the rear driven wheels 14 will be described as unchanged. Incidentally, as a result, the horizontal distance between the driven wheel shaft 14a after the drive wheel shaft 24a and the rear driven wheel 14 of the drive wheel 24 will be spread by [Delta] X _u.

Here, the radius of the driving wheel 24 is R (mm), the wheel radius of the rear driven wheel 14 is r (mm), the height of the shaft 12 of the trailing arm 20 is h _t (mm), and the trailing arm L _r (mm) is the distance between the shaft 12 that is the center of rotation 20 and the front of the frame 10, and L _c (mm) is the horizontal distance between the shaft 12 of the trailing arm 20 and the drive wheel shaft 24a. The length in the front-rear direction is L _f (mm).

  In this case, when the autonomous traveling robot 1 is viewed from the right side with respect to the traveling direction, the coordinates of the drive wheel axis 24a in the orthogonal coordinates (referred to as “orthogonal coordinates A”) with the contact point 24b of the drive wheel 24 as the origin is a = (0, R).

  Here, the trailing arm 20 rotates around the drive wheel shaft 24a. On the Cartesian coordinates with the driving wheel shaft 24a as the origin (referred to as "Cartesian coordinates B"), the elements fixedly coupled to the trailing arm 20 when the trailing arm 20 rotates at an inclination angle η (°). The coordinates after rotation can be expressed as (Equation 1) using the rotation matrix Ra.

Accordingly, the coordinate _b r ₌ the shaft 12 of the trailing arm 20 at the coordinates _{B (x r, y r)} = (L c, h t -R) is the inclination angle eta (°) coordinate _{b r} when the rotation 'is ,

It is.

Further, if the coordinates of the center of gravity G of the combined gravity W of the trailing arm 20, the motor 25, and the drive wheel 24 are b _m = (x _mb , y _mb ), the coordinates b _m = (x _mb , The coordinate b _m ′ when y _mb ) is rotated by the inclination angle η (°) is

It becomes.

  Next, the inclination of the frame 10 will be described.

  In the orthogonal coordinates (referred to as “orthogonal coordinates C”) having the shaft 12 that is the rotation center of the trailing arm 20 as the origin, the rotation matrix Rb is used as the coordinates after rotation of the elements fixedly coupled to the frame 10. And can be expressed as (Equation 4).

As a result, the center coordinates _c u of the rear driven wheel shaft _{14a = (x u, y u} ) = (- L f + L r, r-h t) is zeta (°) coordinates _{c u} when the rotation 'is

Thus, the coordinates c _m ′ when the center-of-gravity coordinates c _m = (x _mc , y _mc ) other than the driving wheel 24 rotate by the inclination angle ζ (°)

It becomes.

  Here, in the orthogonal coordinates (referred to as “orthogonal coordinates D”) with the contact point 14b of the rear driven wheel 14 as the origin, the coordinates of the rear driven wheel axis 14a of the rear driven wheel 14 are d = (0, r). .

  By the way, when the autonomous mobile robot 1 starts, when the trailing arm 20 swings, the height of the shaft 12 that is the center of the trailing arm 20 is lifted upward as compared with the basic posture. Further, the rear driven wheel 14 attached to the rear side of the frame 10 is shifted rearward relative to the ground point 24 b of the driving wheel 24. Furthermore, the height of the ground contact point 14b of the rear driven wheel 14 does not change on the horizontal ground.

  From these facts, it can be seen that the inclination angle ζ (°) of the frame 10 is uniformly determined with respect to the inclination angle η (°) of the trailing arm 20.

  The relationship between the inclination angle ζ (°) of the frame 10 and the inclination angle η (°) of the trailing arm 20 is obtained from the fact that the height of the ground contact point 14b of the rear driven wheel 14 is 0 at the orthogonal coordinate A. Can do.

  In order to represent an arbitrary coordinate on the orthogonal coordinate B on the orthogonal coordinate A, considering that the coordinate of the drive wheel axis 24a of the drive wheel 24 serving as the reference of the orthogonal coordinate B is a, it is as follows.

First, the coordinate a _r of the shaft 12 that is the center of the trailing arm 20 is:

The coordinates a _ml of the center of gravity G of the synthetic gravity W such as the drive wheel 24 are

It becomes.

Similarly, in order to represent an arbitrary coordinate on the Cartesian coordinate C on the Cartesian coordinate A, considering that the coordinate of the drive wheel axis 24a of the drive wheel 24 serving as a reference for the Cartesian coordinate B is a _r , It becomes like this.

First, the coordinate a _u of the rear driven wheel shaft 14a of the rear driven wheel 14 is

The coordinates a _m2 of the center of gravity G other than the drive wheels 24 are

It becomes.

Further, the ground contact point 14b of the rear driven wheel 14 can be expressed as the following coordinate a _u ′ in the orthogonal coordinate A.

  By calculating these equations, the following relationship is established.

  First, from the calculation of the X component,

  From the calculation of the Y component,

It becomes.

Further, when the rotation matrix R _c is used, the arbitrary coordinates on the frame 10 rotated before and after the rotation and the distance from the rotation center do not change. That is,

Because

It becomes.

That is, based on the drive wheels 24, the rear driven wheel 14 is shifted backward by the displacement [Delta] X _u min. As a result, the displacement ΔX _u ′ is

It becomes.

Here, since the driving wheel 24 is considered as the center, the frame 10 of the autonomous traveling robot 1 seems to move backward by the displacement Δx _u, but in reality, the driving wheel is displaced from the frame 10 of the autonomous traveling robot 1 by the displacement Δx _u during acceleration. 24 is moving forward.

  Considering the amount of movement of the center of gravity G of the driving wheel 24 and the like with respect to the driving wheel shaft 24a together with the advancement of the driving wheel 24, the center of gravity G of the combined gravity W of the driving wheel 24 and the like with respect to the frame 10 of the autonomous mobile robot 1 is considered. You can see the amount of movement.

That is, when the coordinate b _m = (x _bm , y _bm ) of the center of gravity G of the synthetic gravity W of the driving wheel 24 or the like is rotated by the inclination angle η (°), the rotated coordinate b _m ′ is

Because

It becomes. Here, the displacement Δx _bm of the movement of the center of gravity G in the front-rear direction is

It is.

  Further, the displacement ΔX of the movement of the center of gravity G of the drive wheel 24 relative to the frame 10 can be expressed by the following equation.

  In the autonomous mobile robot 1 according to the present embodiment, when the position of the center of gravity G of the combined gravity W of the trailing arm 20, the motor 25, and the drive wheel 24 is not set appropriately, effective center of gravity movement cannot be obtained. There is a case.

  That is, the movement of the center of gravity that is advantageous for suppressing the overturn of the autonomous mobile robot 1 occurs when the displacement ΔX satisfies the following equation.

  At this time,

It is.

  Here, the condition of the radius R of the drive wheel 24 that satisfies the displacement ΔX> 0 shown in (Equation 23) will be described.

As the radius R (mm) of the drive wheel 24 increases, the coordinate b of the shaft 12 that is the center of rotation of the trailing arm 20 when the trailing arm 20 is inclined from the basic posture by the inclination angle η (°). affects _r .

Therefore, assuming two autonomous traveling robots 1A and 1B satisfying the relationship of radius Ra> radius Rb of the drive wheels 24, the coordinates of each of them are b _ra = (x _r , y _ra ), b _rb = (x _r , y _rb ). Further, the coordinates after the rotation are set to b _ra ′ = (x _r , y _ra ′), b _rb ′ = (x _r , y _rb ′).

The coordinates b _ra ′ and b _rb ′ of the shaft 12 which is the rotation center of the trailing arm 20 of the two autonomous traveling robots 1A and 1B can be expressed as follows.

  Here, regarding the autonomous traveling robot 1A and the autonomous traveling robot 1B, when the coordinates of the shaft 12 which is the rotation center of the trailing arm 20 at the rotation of the inclination angle η (°) are compared, the movement amount is small together with the x and y coordinates. Become.

  First, regarding the x coordinate,

It is. From this, it can be seen that the coordinate x _ra ′ is positioned ahead of the coordinate x _rb ′.

Here, in the range of 0 ≦ η ≦ 180 °, the coordinate x _r ′ moves to the negative side. Therefore, the coordinate x _ra ′ is positioned ahead of the coordinate x _rb ′. That is, _ra ′ has a smaller moving amount than the coordinate x _rb ′.

  Next, regarding the y coordinate,

It is. From this, it can be seen that y _ra '≦ y _rb ′, and the coordinate y _ra ′ has a smaller moving amount than the coordinate y _rb ′.

Movement amount in the height direction of the shaft 12 as the rotational axis of the trailing arm 20 is equal to the movement amount [Delta] y _r of the overall height of the frame 10. Therefore, the amount of movement Δy _r is,

It becomes.

Further, since the coordinates of the shaft 12 that is the rotation center of the trailing arm 20 are different between the autonomous traveling robot 1A and the autonomous traveling robot 1B, the coordinates c _ua and the coordinates c _ub of the rear driven wheel shaft 14a of the rear driven wheel 14 are also affected. coming out. here,
When c _ua = c _ub = (x _u , y _u ) and the rotation angle ζ _a (°) and the rotation angle ζ _b (°), the coordinates c _ua ′, the coordinates c _ub ′, and the displacement Δy _ua after the rotation are obtained. ', Δy _ub ' can be expressed as follows.

  From these facts, it can be seen that a smaller radius R of the drive wheel 24 is advantageous in increasing the distance between the drive wheel 24 and the rear driven wheel 14 when the trailing arm 20 is inclined.

Actually, when the driving wheel 24 had a radius of 50 mm, 75 mm, 100 mm, 125 mm, and 150 mm and was experimentally manufactured with a simulated robot, the displacement ΔX _u (mm) shown in FIG. 5 was obtained. FIG. 5 is a graph showing the relationship between the radius R of the drive wheel 24 and the displacement ΔX _u (mm) of the drive wheel 24 when the trailing arm 20 is tilted (5 °, 10 °).

  However, in the actual design of the autonomous traveling robot 1, the driving wheel 24 is an important element for determining the traveling speed and the like. For example, if the radius R of the drive wheel 24 is too small, the target speed may not be achieved. For this reason, it is necessary to consider the balance.

Therefore, the condition of the radius r of the rear driven wheel 14 that satisfies the displacement ΔX> 0 will be described with reference to FIG. FIG. 6 is a graph showing the relationship between the radius r of the rear driven wheel 14 and the displacement ΔX _u of the driving wheel 24 when the trailing arm 20 is inclined (5 °, 10 °).

  That is, FIG. 6 is an experiment in which a simulated robot having a radius r of the rear driven wheel 14 of 25 (mm), 50 (mm), 75 (mm), 100 (mm), and 125 (mm) is experimentally manufactured. .

  From the results shown in FIG. 6, it can be seen that a larger radius r of the rear driven wheel 14 is advantageous in increasing the distance between the drive wheel 24 and the rear driven wheel 14.

Next, the condition of the height h _t of the trailing arm 20 to meet the displacement [Delta] X _{u> 0} of the drive wheel 24 will be described with reference to FIG. FIG. 7 is a graph showing the relationship between the height ht of the trailing arm 20 and the displacement ΔX _u of the drive wheel 24 when the trailing arm 20 is inclined (5 °, 10 °).

  That is, FIG. 7 shows a simulation robot in which the height ht of the shaft 12 that is the rotation center of the trailing arm 20 is 180 (mm), 220 (mm), 260 (mm), 300 (mm), and 340 (mm). This is a prototype and an experiment.

  From the results shown in FIG. 7, it can be seen that the higher shaft 12 that is the center of rotation of the trailing arm 20 is advantageous in increasing the distance between the driving wheel 24 and the rear driven wheel 14.

Next, the condition of the horizontal distance L _c of the shaft 12 as the rotational axis of the trailing arm 20 to meet the displacement [Delta] X _{u> 0} and the drive wheel shaft 24a, it will be described with reference to FIG. FIG. 8 shows the horizontal distance L _c between the shaft 12 that is the rotation center of the trailing arm 20 and the driving wheel shaft 24a and the displacement ΔX _{u of the} driving wheel 24 when the trailing arm 20 is inclined (5 °, 10 °). It is a graph which shows the relationship.

  That is, FIG. 8 shows that the horizontal distance Lc between the shaft 12 that is the rotation center of the trailing arm 20 and the drive wheel shaft 24a is 70 (mm), 100 (mm), 130 (mm), 150 (mm), 180 (mm). ) And simulated and experimented.

  From the results shown in FIG. 8, a shorter horizontal distance between the shaft 12 that is the center of rotation of the trailing arm 20 and the drive wheel shaft 24 a is advantageous in increasing the distance between the drive wheel 24 and the rear driven wheel 14. I understand that.

Next, the condition of the longitudinal length L _f of the frame 10 that satisfies the displacement ΔX _u > 0 will be described with reference to FIG. FIG. 9 is a graph showing the relationship between the longitudinal length L _f of the frame 10 and the displacement ΔX _u of the drive wheel 24 when the trailing arm 20 is tilted (5 °, 10 °).

That is, in FIG. 9, an experiment was conducted by experimentally producing simulated robots having a longitudinal length L _f of the frame 10 of 100 (mm), 200 (mm), 300 (mm), 400 (mm), and 500 (mm). It is.

From the results shown in FIG. 9, it can be seen that a longer front-rear direction length L _f of the frame 10 is advantageous in increasing the distance between the driving wheel 24 and the rear driven wheel 14.

  As described above, the autonomous mobile robot 1 has the frame 10, two or more trailing arms 20, the motor 25 as a power source, and four or more wheels, and two of the wheels function as drive wheels 24. The wheels other than the drive wheel 24 function as the rear driven wheel 14 and the front driven wheel 13 which are driven wheels.

  The two trailing arms 20 are centered on the shaft 12, which is an axis perpendicular to the plane perpendicular to the traveling direction of the autonomous traveling robot 1, and the trailing arm 20 is more autonomous than the shaft 12. The drive wheels 24 and 24 are arranged one by one on the trailing arm 20 so that the lengths of the drive wheel shafts 24a of the shaft 12 and the drive wheel 24 are the same. Yes. The rotating shaft of the motor 25 coupled to each of the trailing arms 20 and 20 is joined to the rotating shaft of the drive wheel 24.

  The end of the trailing arm 20 opposite to the shaft 12, which is the center of rotation, is connected to a rod 22 coupled to the frame 10, and the trailing arm 20 swings with the rod 22 as a guide. Further, a compression spring 21 is disposed around the rod 22 to apply an elastic force to the drive wheel 24 in a vertically downward direction.

  Further, at least one or more front driven wheels 13 and rear driven wheels 14 are arranged in front and rear of the drive wheels 24, respectively, and the front driven wheels 13 and the rear driven wheels 14 are respectively coupled to the frame 10. Each of the front driven wheel 13 and the rear driven wheel 14 has a mechanism that rotates around a front driven wheel shaft 13a and a rear driven wheel shaft 14a that are perpendicular to the horizontal plane. The center of gravity G of the combined gravity W including the left and right trailing arms 20, the driving wheels 24, the motor 25, and the driving wheel mounting portion 23 is disposed at a position lower than the height of the shaft 12 that is the center of rotation of the trailing arm 20. Has been.

  Further, the autonomous mobile robot 1 has a driving wheel radius, a driven wheel radius, a rotational center height of the trailing arm 20, a horizontal distance between the rotational center of the trailing arm 20 and the driving wheel shaft 24a, and a length in the front-rear direction of the frame 10. It has come to be specified.

  As described above, the autonomous mobile robot 1 of the present embodiment rotates the frame 10 with the frame 10 as the base and the front side, which is one side in the front-rear direction on the lower side of the frame 10, with the shaft 12 as the rotation axis. A trailing arm 20 as a drive unit support member supported by the frame 10 so as to be vertically expandable and contractable on the rear side that is pivotally supported and that is the other side in the front-rear direction on the lower side of the frame 10, and the trailing arm 20 A drive unit DR including a rotatable drive wheel 24 attached to the motor, a motor 25 as a power source attached to the trailing arm 20 and driving the drive wheel 24, and at least the other side of the drive wheel 24 in the front-rear direction. And a rear driven wheel 14 as a rotatable other side auxiliary wheel supported by the frame 10, and a drive unit DR and a trailing arm 20. The center of gravity G of the combined center of gravity of the adult gravity W is present at a position lower than the shaft 12 of the trailing arm 20.

  According to the above configuration, for example, when the autonomous traveling robot 1 starts, accelerates, or when an external force is applied backward with respect to the traveling direction (hereinafter, referred to as “starting etc.”), the driving wheel 24 is moved. Go forward and move forward. On the other hand, the frame 10 tends to be stopped by the law of inertia. As a result, the frame 10 is lifted on the front side, and a force acts to rotate around the ground contact point 14 b of the rear driven wheel 14. As a result, if no countermeasure is taken, the autonomous mobile robot 1 rotates backward and falls.

  Here, in the present embodiment, the driving wheel 24 and the motor 25 that drives the driving wheel 24 are mounted on the trailing arm 20 that is separate from the frame 10. The trailing arm 20 is rotatably supported on the frame 10 by the shaft 12 on the front side below the frame 10, and is supported by the frame 10 so as to be vertically extendable on the rear side below the frame 10. ing.

  As a result, when the frame 10 is about to rotate around the ground contact point 14 b of the rear driven wheel 14 when the autonomous mobile robot 1 is started, the trailing arm 20 has the front shaft 12 supported by the frame 10. Because of this, they try to rotate together around the rear vertical stretchable part. However, the counter-rotation moment acts on the rotational moment in the opposite direction to the combined gravity W of the drive wheel 24, the motor 25, and the trailing arm 20 with the rear vertical expansion / contraction portion as the center. Then, due to the action of the rotational moment and the counter-rotational moment, the rear side vertical expansion / contraction portion contracts to cancel the rotation.

  As a result, the rotational moment of the frame 10 is weakened, so that the autonomous mobile robot 1 can be prevented from rotating and falling over.

  Here, in the present embodiment, the center of gravity G of the combined gravity W of the drive wheel 24, the motor 25, and the trailing arm 20 exists at a position lower than the shaft 12 that is the rotation center of the trailing arm 20. For this reason, when the autonomous mobile robot 1 starts, the distance between the drive wheel shaft 24a of the drive wheel 24 and the rear driven wheel shaft 14a of the rear driven wheel 14 is instantaneously increased, and accordingly, the center of gravity of the combined gravity W is increased. G moves forward in the direction of travel.

  As a result, the gravity center G of the combined gravity W of the driving wheel 24, the motor 25, and the trailing arm 20 is less likely to fall than when the center of gravity G is higher than the shaft 12 that is the rotation center of the trailing arm 20. .

  Here, in the present embodiment, the drive unit DR and the frame 10 that is the upper structure are not divided in order to prevent overturning. Specifically, the frame 10 includes a rotatable rear driven wheel 14 supported by the frame 10, and the driving wheel 24 is also supported by the frame 10 via the shaft 12 of the trailing arm 20.

  Accordingly, it is possible to provide the autonomous mobile robot 1 that can prevent the vehicle 10 from falling in at least one of the front and rear directions without dividing the upper structure frame 10 and the drive unit DR.

  In the present embodiment, by setting one side of the frame 10 in the front-rear direction as the front side and the other side of the front-rear direction as the rear side, it is possible to prevent the rotation from falling backward at the time of starting or the like. Yes. However, conversely, by setting one side of the frame 10 in the front-rear direction as the rear side and the other side of the front-rear direction as the front side, the autonomous mobile robot 1 can rotate forward and fall down when suddenly starting backward. It can be prevented. In other words, in the present embodiment, it is possible to prevent a fall in at least one of the front and rear directions.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. The configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and explanation thereof is omitted.

  In the autonomous traveling robot 2 of the present embodiment, in addition to the configuration of the autonomous traveling robot 1 of the first embodiment, the rear driven wheel 14 is suspended from the frame 10 by the compression spring 15, and the front driven wheel 13 is The difference is that the frame 10 is suspended by a compression spring 16.

  The configuration of the autonomous mobile robot 2 according to the present embodiment will be described with reference to FIG. FIG. 10 is a side view showing the configuration of the autonomous mobile robot 2 of the present embodiment. The right side of FIG. 10 is the front side of the autonomous mobile robot 2.

  In the autonomous traveling robot 2 of the present embodiment, as shown in FIG. 10, the rear driven wheel 14 is suspended by a compression spring 15 as an elastic body at the lower end of the frame 10. Thereby, for example, when the autonomous mobile robot 2 starts, accelerates, and when an external force is applied backward with respect to the traveling direction, the fall is suppressed.

  That is, when the autonomous traveling robot 2 starts, the gravity of the autonomous traveling robot 2 acts on the grounding point 14b of the rear driven wheel 14 due to inertial force, and the frame 10 moves around the grounding point 14b of the rear driven wheel 14. Rotates counterclockwise. At this time, in the present embodiment, since the rear driven wheel 14 is suspended by the compression spring 15 at the lower end of the frame 10, the force applied to the ground contact point 14b of the rear driven wheel 14 is suppressed, and the rotational force is weakened. It is possible to suppress the autonomous traveling robot 2 from falling.

  Here, in the present embodiment, as shown in FIG. 10, in order to suppress the fall when the autonomous traveling robot 2 starts, accelerates, and when an external force is applied backward with respect to the traveling direction. In addition, a stopper 22 c made of, for example, a cylindrical member can be provided on the lower end of the rod 22 and on the upper side of the trailing arm 20. Thereby, the compression spring is a compression spring 21 ′ shorter than the compression spring 21 of the first embodiment.

  When the stopper 22c is provided, the length of the compression spring 21 is reduced. As a result, when the autonomous traveling robot 2 starts, the rotational width of the trailing arm 20 is suppressed, and the autonomous traveling robot 2 that reaches the angle of the restriction region of the trailing arm 20 by the stopper 22c is Unlike this, the grounding point 14b of the rear driven wheel 14 is applied to the weight, not the grounding point 24b of the driving wheel 24.

  At this time, since the rear driven wheel 14 is suspended by the compression spring 15, the compression spring 15 absorbs the force that causes the fall, the rotational force of the frame 10 is weakened, and the autonomous traveling robot 2 falls. Can be suppressed.

  In the above description, the measures for preventing the autonomous traveling robot 2 from overturning when the autonomous traveling robot 2 starts, accelerates, and when an external force is applied backward with respect to the traveling direction have been described. On the other hand, when an inertial force at a sudden stop, an inertial force at a sudden deceleration, or a forward external force is applied, the above-described configuration cannot provide a fall prevention effect.

  Therefore, in the autonomous traveling robot 2 of the present embodiment, as shown in FIG. 10, it is preferable that the front driven wheel 13 is also suspended by a compression spring 16 as an elastic body. Thereby, when the inertial force when the autonomous traveling robot 2 is suddenly stopped, the inertial force of rapid deceleration, or the forward external force is applied, the gravity of the autonomous traveling robot 2 acts on the ground contact point 13b of the front driven wheel 13. This force can be reduced by the compression spring 16.

  Therefore, even when the inertial force when the autonomous traveling robot 2 is suddenly stopped, the inertial force of sudden deceleration, or the forward external force is applied, the fall can be prevented.

  Note that the rear driven wheel 14 and the front driven wheel 13 are provided in pairs on the left and right in the autonomous traveling robot 2 of the present embodiment. Therefore, by adopting a configuration in which the pair of left and right rear driven wheels 14 and front driven wheels 13 are suspended by compression springs 15 and 16, the structure is strong against not only the front-rear direction but also the left-right direction falling. . In other words, for a left-right fall, the left and right rear driven wheels 14 and 14 and the left and right front driven wheels 13 and 13 are applied to the rear driven wheels 14 and 14 or the front driven wheels 13 and 13, respectively. The load can be relaxed.

  As described above, the autonomous mobile robot 2 according to the present embodiment has the front driven wheel 13 as a rotatable one-side auxiliary wheel supported by the frame 10 on the front side which is one side in the front-rear direction with respect to the driving wheel 24. Is further provided. The rear driven wheel 14 and the front driven wheel 13 are suspended from the frame 10 by compression springs 15 and 16 as elastic bodies.

  As a result, when the autonomous traveling robot 1 starts, etc., when the autonomous traveling robot 2 rotates backward and falls around the ground contact point 14b of the rear driven wheel 14, or when the autonomous traveling robot 2 suddenly stops, the front driven wheel 13 When the autonomous mobile robot 2 rotates and falls forward about the ground contact point 13b, the load applied to the ground contact points 14b and 13b is alleviated by the compression springs 15 and 16, respectively.

  As a result, it is possible to prevent the autonomous mobile robot 2 from rotating backward or falling forward.

  Here, in the autonomous traveling robot 2 of the present embodiment, regarding the stability, when the trailing arm 20 swings upward from the basic posture during sudden deceleration, the distance between the driving wheel 24 and the rear driven wheel 14 is narrowed. . In this case, assuming that the inertial force applied to the autonomous mobile robot 2 is applied forward, the distance between the driving wheel 24 and the front driven wheel 13 is also increased in this case, so that it is considered that there is no problem with respect to stability. . However, the range in which the distance between the driving wheel 24 and the front driven wheel 13 can be increased by the trailing arm 20 swinging upward from the basic posture is that the front driven wheel 13 and the rear driven wheel 14 are suspended. It is regulated by the stroke of the compression springs 15 and 16 which are elastic bodies. This is because the shaft 12 that is the rotation center of the trailing arm 20 is provided on the front side of the autonomous mobile robot 2. If the trailing arm 20 attempts to swing upward from the basic posture, the frame 10 is relatively forced to be pressed against the ground due to the structure. At this time, when the front driven wheel 13 and the rear driven wheel 14 are suspended by the compression springs 15 and 16, the frame 10 can sink by the stroke of the compression springs 15 and 16. However, when the stroke of the compression springs 15 and 16 is exceeded, the frame 10 is fixed at the distance between the driving wheel 24 and the front driven wheel 13 and the rear driven wheel 14 in the most depressed position. The stability improvement due to the change in distance is limited.

  In the autonomous mobile robot 2 according to the present embodiment, the structure is such that the compression springs 15 and 16 do not easily fall forward, so that it is difficult for the bicycle to fall during an emergency stop.

  For example, in the case of six wheels, even if the front driven wheel 13 and the rear driven wheel 14 are fixed to the frame 10, the position of the drive wheel 24 is variable, Similar effects can be obtained. However, when the front driven wheel 13 and the rear driven wheel 14 are not suspended, or when the front driven wheel 13 and the rear driven wheel 14 are suspended by the compression springs 15 and 16 of the same stroke, Since there is a possibility that the load is supported by the three wheels of the rearmost rear driven wheels 14 and 14 and the drive wheel 24, the rear driven wheels 14 and 14 close to the drive wheel 24 and the drive It is considered that a device such as setting a long distance to the wheel 24 is necessary.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to FIG. The configurations other than those described in the present embodiment are the same as those in the first embodiment and the second embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 1 and Embodiment 2 are given the same reference numerals, and explanation thereof is omitted.

  As shown in FIG. 11, the autonomous traveling robot 3 of the present embodiment has a position of the motor 25 in the frame compared to the configurations of the autonomous traveling robot 1 of the first embodiment and the autonomous traveling robot 2 of the second embodiment. The difference is that the motor 25 ′ has moved to the front side of 10.

  The configuration of the autonomous mobile robot 3 of the present embodiment will be described based on FIG. FIG. 11 is a side view showing the configuration of the autonomous mobile robot 3 of the present embodiment. The right side of FIG. 11 is the front side of the autonomous mobile robot 3.

  As shown in FIG. 11, in the autonomous traveling robot 3 of the present embodiment, the motor 25 ′ attached to the drive wheel mounting portion 23 is the same as that of the autonomous traveling robot 1 of the first embodiment and the second embodiment. The position of the motor 25 in the autonomous mobile robot 2 is attached to the position moved to the front side of the frame 10. As a result, in the present embodiment, the rotating shaft of the motor 25 ′ and the driving wheel shaft 24a of the driving wheel 24 are not coaxial, and the rotating shaft of the motor 25 ′ is connected to the driving wheel shaft 24a of the driving wheel 24 via a gear (not shown). It is connected.

  That is, in the autonomous traveling robot 1 of the first embodiment and the autonomous traveling robot 2 of the second embodiment, the stability is affected by the position of the center of gravity G of the combined gravity W of the trailing arm 20, the motor 25, and the driving wheel 24. Receive. For example, when the center of gravity G of the combined gravity W of the trailing arm 20, the motor 25, and the driving wheel 24 is above the driving wheel shaft 24 a of the driving wheel 24, when the trailing arm 20 is tilted, The horizontal distance between the drive wheel shaft 24a and the rear driven wheel shaft 14a of the rear driven wheel 14 is widened, whereas the horizontal distance between the center of gravity G of the combined gravity W and the rear driven wheel shaft 14a of the rear driven wheel 14 is narrowed.

  Therefore, in the present embodiment, when the autonomous traveling robot 3 starts, accelerates, and when an external force is applied backward with respect to the traveling direction, the fall prevention effect appears when the trailing arm 20 is inclined. The distance between the driving wheel shaft 24a of the driving wheel 24 and the rear driven wheel shaft 14a of the rear driven wheel 14 is such that the distance between the center of gravity G of the combined gravity W and the rear driven wheel shaft 14a of the rear driven wheel 14 is reduced. It was only when the center of gravity G was set so as to be in a larger range.

  However, in the present embodiment, the fall prevention effect can be further enhanced by moving the center of gravity of the motor 25 ′ connected to the drive wheel 24 in the direction away from the rear driven wheel shaft 14 a of the rear driven wheel 14. It has become a thing.

  That is, in this embodiment, when the autonomous traveling robot 3 is installed on a plane and the posture of the trailing arm 20 in a state where no external force is applied in the horizontal direction is defined as the basic posture of the trailing arm 20, The tray when the trailing arm 20 swings below the basic position with respect to the distance of the center of gravity of the motor 25 'when the shaft 12 which is the rotation center of the arm 20 and the trailing arm 20 takes the basic position. In this configuration, the distance between the shaft 12 that is the rotation center of the ring arm 20 and the center of the motor 25 ′ is reduced.

  As described above, in the autonomous traveling robot 3 of the present embodiment, the motor 25 ′ as a power source is positioned on the front side where the center of gravity of the motor 25 ′ is one side in the front-rear direction with respect to the center of gravity of the drive wheel 24. Is attached to the trailing arm 20.

  Thereby, the position of the center of gravity G of the combined gravity W of the driving wheel 24, the driving unit DR including the motor 25 ', and the trailing arm 20 can be brought to the front as much as possible.

  As a result, when the autonomous mobile robot 2 starts, for example, the anti-rotation moment due to the combined gravity W of the driving wheel 24, the drive unit DR including the motor 25 ′, and the trailing arm 20 against the rotational moment that rotates the frame 10 backward. Can be increased.

  Therefore, it is possible to prevent the autonomous traveling robot 2 from rotating backward and falling when the autonomous traveling robot 2 starts.

[Embodiment 4]
The following will describe still another embodiment of the present invention with reference to FIG. The configurations other than those described in the present embodiment are the same as those in the first to third embodiments. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 3 are given the same reference numerals, and descriptions thereof are omitted.

  In the autonomous traveling robot 1 of the first embodiment to the autonomous traveling robot 3 of the third embodiment, the shaft 12 that is the rotation center of the trailing arm 20 is fixed to the frame 10 so as to be rotatable. On the other hand, the autonomous traveling robot 4 of the present embodiment differs in that the shaft 12 that is the rotation center of the trailing arm 20 is movable with respect to the frame 10 as shown in FIG. Yes.

  The configuration of the autonomous mobile robot 4 according to the present embodiment will be described with reference to FIG. FIG. 12 is a side view showing the configuration of the autonomous mobile robot 4 of the present embodiment. The right side of FIG. 12 is the front side of the autonomous mobile robot 4.

  In the autonomous traveling robot 1 of the first embodiment to the autonomous traveling robot 3 of the third embodiment, a sufficient effect may not be exhibited due to the setting of the center of gravity G synthesized by the trailing arm 20, the motor 25, and the drive wheel 24. It is as described in the third embodiment.

  Therefore, in the present embodiment, as shown in FIG. 12, the shaft 12 that is the rotation center of the trailing arm 20 is configured to be movable in the front-rear direction with respect to the frame 10. As a result, with respect to the distance D between the front frame 10c that hangs down from the frame 10 when the trailing arm 20 takes the basic posture and the shaft 12 that is the rotation center of the trailing arm 20, the trailing arm 20 moves from the basic posture. Also, the distance between the front frame 10c and the shaft 12 which is the center of rotation of the trailing arm 20 when the rear swings downward is shortened.

  Specifically, as shown in FIG. 12, the shaft holder 11 ′ that holds the shaft 12 that is the rotation center of the trailing arm 20 is autonomous so that it can move in the front-rear direction for each drive wheel 24. A mechanism for holding a linear motion shaft 17 provided along the front-rear direction of the traveling robot 4 is provided. With this mechanism, the trailing arm 20 itself can move in the front-rear direction.

  Further, the trailing arm 20 is provided with a plate cam 26 as a moving member at the time of contraction around the driving wheel shaft 24a of the driving wheel 24 as a rotation center. The plate cam 26 is installed so as to contact the frame structure 10 b fixedly joined to the frame 10. When the trailing arm 20 is in the basic posture, the distance between the frame structure 10b and the drive wheel shaft 24a is minimized, and as the trailing arm 20 is tilted backward from the basic posture, the frame structure 10b. And the drive wheel shaft 24a have a large structure. The trailing arm 20 is suspended from the front by a plurality of compression springs 18.

  With this structure, the trailing arm 20 is pushed forward by the plate cam 26 when the trailing arm 20 swings backward from the basic posture downward. As a result, the center of gravity G of the combined gravity W of the trailing arm 20, the motor 25, and the drive wheel 24 can be effectively moved forward.

  That is, the autonomous mobile robot 4 of the present embodiment has a configuration in which the shaft 12 that is the rotation center of the trailing arm 20 can move with respect to the frame 10. Further, the frame 10 and the trailing arm 20 when the trailing arm 20 swings below the basic posture with respect to the distance between the frame 10 and the trailing arm 20 when the trailing arm 20 takes the basic posture. This is a configuration in which the distance from the shaft 12 that is the center of rotation is shortened.

  As described above, in the autonomous traveling robot 4 of the present embodiment, the trailing arm 20 as the drive unit support member is supported by the frame 10 as the base body so as to be movable in the front-rear direction, and in the trailing arm 20. As the compression spring 18 contracts to the rear frame 10 that is the other side in the front-rear direction, a plate cam 26 is provided as a moving member during contraction that moves the trailing arm 20 to the front side that is one side in the front-rear direction. ing.

  As a result, when the autonomous mobile robot 4 starts, the trailing arm 20 equipped with the drive unit DR including the drive wheel 24 and the motor 25 moves to the front side. As a result, the position of the center of gravity G of the combined gravity W of the driving wheel 24, the driving unit DR including the motor 25, and the trailing arm 20 and the other side auxiliary wheel serving as a fulcrum when the autonomous traveling robot 4 rotates backward. The distance between the rear driven wheel 14 and the ground contact point 14b increases.

  As a result, when the autonomous mobile robot 4 starts, the counter-rotation moment due to the combined gravity W of the drive wheel 24, the drive unit DR including the motor 25, and the trailing arm 20 that resists the rotation moment that rotates the frame 10 backward is generated. Can be bigger.

  Therefore, the autonomous traveling robot 4 can be prevented from rotating backward and falling when the autonomous traveling robot 4 is started.

[Embodiment 5]
The following will describe still another embodiment of the present invention with reference to FIGS. Configurations other than those described in the present embodiment are the same as those in the first to fourth embodiments. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 4 are given the same reference numerals, and descriptions thereof are omitted.

  In the autonomous traveling robot 1 to the autonomous traveling robot 4 of the first embodiment, the fall prevention has been described.

  In the autonomous traveling robot 5 of the present embodiment, in addition to the structure for preventing the overturning of the autonomous traveling robot 1 of the first embodiment to the autonomous traveling robot 4 of the fourth embodiment, the traveling stability is improved on a depressed terrain or a raised terrain. A structure for achieving the above will be described.

  Since the configuration of the autonomous mobile robot 5 of the present embodiment is the same as the configuration of the autonomous mobile robot 1 in the first embodiment, the description thereof is omitted.

  The autonomous mobile robot 4 according to the fourth embodiment moves backward due to inertial force at the time of sudden start, inertial force at the time of sudden acceleration, or external force by movement of the center of gravity G synthesized by the trailing arm 20, the motor 25, and the drive wheel 24. As already mentioned, the structure is strong against falls.

  In the autonomous traveling robot 5 of the present embodiment, not only that, it is possible to improve the traveling stability on the depressed terrain and the raised terrain.

In conclusion, the autonomous traveling robot 5 according to the present embodiment has the total weight of the autonomous traveling robot 5 as M (kg), the gravitational acceleration as g (ms ⁻² ), and the climbing ability of the autonomous traveling robot 5 as the angle θ. (°), the friction coefficient is μ _k , the combined weight of the trailing arm 20, the drive wheel 24, and the motor 25 is W (N), and the displacement of the compression spring 21 when the trailing arm 20 is in the basic posture is Δy _p When the spring coefficient of the compression spring 21 is k (N / mm) and the distance from the shaft 12 that is the rotation center of the trailing arm 20 to the point of action of the compression spring 21 is d _k (mm),
Mgsin θ <μ _k (ΣW cos θ + Σ _k (Δy _p + d _k θ (π / 180))) <Mg cos θ
To meet the relationship.

  The principle for improving the running stability in the depressed terrain and the raised terrain by the autonomous running robot 5 having the above configuration will be described with reference to FIG. FIG. 13 is a side view showing the principle for improving the traveling stability of the autonomous traveling robot 5 in the depressed terrain.

First, when the radius of the front driven wheel 13 and the rear driven wheel 14 is r (mm) and the radius of the drive wheel 24 is R (mm), the compression spring 21 is moved from the shaft 12 which is the rotation center of the trailing arm 20. The horizontal distance to the center of is d _k (mm).

  At this time, when the autonomous traveling robot 5 falls into the dent having the angle θc (°) (<0), both the front and the rear, the frame 10 maintains the horizontal posture and the trailing arm 20 becomes a horizontal plane. The angle is substantially equal to θc (°). Strictly speaking, it is necessary to consider the difference in the amount of bending between the front driven wheel 13 and the rear driven wheel 14, but this is an error range.

The amount of spring displacement Δy _c (mm) is

It is.

When the autonomous vehicle is in a horizontal posture, the grounding point 13b of the front driven wheel 13, the grounding point 14b of the rear driven wheel 14, and the grounding point 24b of the driving wheel 24 are equal in height, so that the trailing arm 20 is substantially horizontal. Shall be maintained. At this time, in addition to the own weight w (N) per trailing arm 20, the force from the compression spring 21 acts on the ground, and the vertical drag _nk equal to this force is multiplied by the dynamic friction coefficient μ _k ′. The frictional force f _kp works.

The force applied to the ground E from the compression spring 21 is assumed to be bent by Δy _p (mm) when the compression spring 21 having a natural length y ₀ (mm) is horizontal. Assuming that the spring constant is k (N / mm) per one compression spring 21, the frictional force f _kp applied to the drive wheel 24 in the horizontal state can be expressed by the following (Equation 35).

As shown in FIG. 13, when the autonomous mobile robot 5 falls into the depression of the angle θc (°), the frictional force f _kp applied to the drive wheel 24 at the moment when the drive wheel 24 leaves the back slope is 36).

In addition, when the weight of the autonomous mobile robot 5 is M (kg) and the gravitational acceleration g (mm / s ² ), the driving wheel 24 is required if the dynamic friction force f _k is not larger than the gravity Mgsin θc acting on the plane parallel to the slope. Can't slide and move forward. For this reason, the following inequality must be satisfied.

  Next, the principle for improving the running stability on the raised terrain by the autonomous running robot 5 of the present embodiment will be described with reference to FIG. FIG. 14 is a schematic diagram showing the principle for improving the running stability of the autonomous running robot 5 on the raised terrain.

First, when the autonomous traveling robot 5 travels on a raised terrain having an angle θc (°) (θ> 0) in both the front and rear, the displacement amount Δy _c (mm) of the compression spring 21 is the same as in (Equation 34). From the calculation

It is.

When the autonomous traveling robot 5 travels on the raised terrain, the compression spring 21 of the trailing arm 20 is further compressed as compared with the horizontal state, so that the force exerted on the ground from the driving wheel 24 becomes larger. However, since the force that the autonomous mobile robot 5 exerts on the ground E is uniformly determined as Mgcos θ _c by the gravity and the inclination angle, the front driven wheel 13 and the rear driven wheel are increased as the force applied to the ground E from the drive wheel 24 increases. The force exerted on the ground E from the driving wheel 14 is also reduced. When the force exerted on the ground E from the front driven wheel 13 and the rear driven wheel 14 becomes zero, the front driven wheel 13 and the rear driven wheel 14 float in the air, so that traveling becomes unstable. As a result, the following inequality must be satisfied.

Furthermore, since the force exerted by the front driven wheel 13 and the rear driven wheel 14 needs to be 0 or more, the vertical drag n _jf > 0 and the vertical drag n _jr > 0 must be satisfied.

From (Equation 39) and the normal force n _jf > 0 and the normal force n _jr > 0, the dynamic friction coefficient f _k of the drive wheel 24 may satisfy the following relational expression.

  Further, regarding the front driven wheel 13 and the rear driven wheel 14, when traveling forward, the horizontal distance between the front driven wheel shaft 13 a of the front driven wheel 13 and the driving wheel shaft 24 a of the driving wheel 24 and the driving wheel shaft 24 a of the driving wheel 24. And the horizontal distance between the rear driven wheel shaft 14a and the rear driven wheel shaft 14a is L (mm).

  At this time, when the front driven wheel 13 and the rear driven wheel 14 are free casters, in order for the front driven wheel 13 and the rear driven wheel 14 to follow the traveling direction, the ground contact point 13b and the rear driven wheel of each front driven wheel 13 are used. The 14 grounding points 14b need to be displaced q (mm) rearward with respect to the traveling direction from the front driven wheel shaft 13a and the rear driven wheel shaft 14a which are the respective horizontal rotation centers.

Therefore, the distance L _P = L−q (mm) between the ground point 13b of the front driven wheel 13 and the ground point 24b of the driving wheel 24, and the ground point 24b of the driving wheel 24 and the ground point 14b of the rear driven wheel 14 The distance L _B can be expressed as L + q (mm).

  In addition, when the center of gravity of the autonomous traveling robot 5 is behind the driving wheel 24 by a distance s (mm), the force applied to the front driven wheel 13 and the rear driven wheel 14 satisfies the following equation from the balance of moments.

Here, when the distance s ≧ 0, when the normal force n _jf > 0 is satisfied,

On the other hand, when the distance s <0, when the normal drag n _jr > 0 is satisfied,

Thus, stable running is possible even on raised terrain.

That is, when the center of gravity G is located on the driving wheel 24 or behind the driving wheel 24, the vertical drag n _jr > 0 must be satisfied. On the other hand, when the center of gravity G is located on the front side of the drive wheel 24, it is necessary to satisfy the vertical drag n _jf > 0.

As described above, in the autonomous traveling robot 5 of the present embodiment, the trailing arm 20 as the driving unit supporting member is vertically moved to the frame 10 on the rear side which is the other side in the front-rear direction on the lower side of the frame 10 as the base. It is supported by a compression spring 21 as an elastic member so that it can extend and contract in the direction, the total weight of the autonomous mobile robot 5 is M (kg), the acceleration of gravity is g (ms ⁻² ), the climbing ability is θ (°), The friction coefficient is μ _k , the combined weight of the driving unit DR and the trailing arm 20 is W (N), the displacement of the compression spring 21 in the basic posture in the trailing arm 20 is Δy _p , and the spring coefficient of the compression spring 21 Is k (N / mm), and the distance from the shaft 12 that is the rotation center of the trailing arm 20 to the point of action of the compression spring 21 is d _k (mm),
Mgsin θ <μ _k (ΣW cos θ + Σ _k (Δy _p + d _k θ (π / 180))) <Mg cos θ
Satisfy the relationship.

  Note that the basic posture of the trailing arm 20 refers to the posture of the trailing arm 20 in a state in which no horizontal external force is applied to the autonomous traveling robot 5 installed on a plane.

  As a result, when the autonomous traveling robot 5 moves to a raised terrain or a depressed terrain, it can be prevented from rotating and falling, and the traveling stability can be improved.

[Summary]
The autonomous mobile robot 1 according to the first aspect of the present invention has a base (frame 10) and a rotary shaft (shaft 12) on one side in the front-rear direction below the base (frame 10). A drive support member (trailing arm 20) that is rotatably supported and supported on the base body (frame 10) so as to be vertically extendable on the other side in the front-rear direction on the lower side of the base body (frame 10); , A rotatable drive wheel 24 mounted on the drive unit support member (trailing arm 20), and a power source (motor) mounted on the drive unit support member (trailing arm 20) and driving the drive wheel 24. 25) and a rotatable other auxiliary wheel (rear follower) supported by the base body (frame 10) at least on the other side in the front-rear direction than the driving wheel 24. A combined center of gravity (center of gravity G) of the drive unit DR and the drive unit support member (trailing arm 20) is a rotation axis (shaft 12) of the drive unit support member (trailing arm 20). It is characterized by existing in a lower position.

  According to the above invention, for example, when the autonomous traveling robot starts, accelerates, or when an external force is applied backward with respect to the traveling direction (hereinafter referred to as “starting or the like”), the driving is performed. The wheel moves forward and proceeds to one side in the front-rear direction. On the other hand, the base body tends to stop according to the law of inertia. As a result, the base body is lifted on the front side, and the force to rotate around the grounding point of the other side auxiliary wheel that is the rear side auxiliary wheel. Work. As a result, if no countermeasures are taken, the autonomous mobile robot rotates to the rear side and falls.

  Here, in the present invention, the driving wheel and the power source for driving the driving wheel are mounted on a driving unit support member separate from the base body. The drive unit support member is rotatably supported on the base by a rotating shaft on one side in the front-rear direction on the lower side of the base and on the other side in the front-back direction on the lower side of the base. It is supported to be stretchable.

  As a result, when the base body tries to rotate around the grounding point of the other auxiliary wheel on the rear side, such as when the autonomous traveling robot starts, the driving wheel support member has the front rotation shaft supported by the base body. So, it tries to rotate together around the rear vertical stretchable part. However, with respect to this rotational moment, the combined gravity of the drive wheel, the drive source, and the drive wheel support member acts in the opposite direction to this rotational moment, centering on the rear vertical expansion / contraction portion. Then, due to the action of the rotational moment and the counter-rotational moment, the rear side vertical expansion / contraction portion contracts to cancel the rotation.

  As a result, since the rotational moment of the base body is weakened, it is possible to prevent the autonomous traveling robot from rotating and falling over.

  In particular, in the present invention, the center of gravity of the combined gravity of the drive wheel, the drive source, and the drive wheel support member exists at a position lower than the rotation axis that is the rotation center of the drive wheel support member. For this reason, when the autonomous mobile robot starts, the distance between the wheel axis of the driving wheel and the wheel axis of the other auxiliary wheel is instantaneously widened, and the gravity center of the combined gravity moves forward in the traveling direction accordingly. To do.

  As a result, the gravity center of the combined gravity of the drive wheel, the drive source, and the drive wheel support member is less likely to fall than when the center of gravity exists at a position higher than the rotation axis that is the rotation center of the drive wheel support member.

  Here, in the present invention, the drive unit and the upper structure are not divided in order to prevent overturning. Specifically, the base is provided with the other side auxiliary wheel that is rotatable and supported by the base, and the driving wheel is also supported by the base via the rotation shaft of the driving wheel support member.

  In the present invention, by setting one side of the base in the front-rear direction as the front side and the other side of the front-rear direction as the rear side, it is possible to prevent the rotation from falling backward at the time of starting. However, conversely, by setting one side of the base in the front-rear direction as the rear side and the other side in the front-rear direction as the front side, it is possible to prevent the autonomous traveling robot from rotating and falling forward when suddenly starting backward. become. In other words, according to the present invention, it is possible to prevent a fall in at least one of the front and rear directions.

  Therefore, it is possible to provide an autonomous traveling robot that can prevent the vehicle from falling in at least one of the front and rear directions without dividing the upper structure and the drive unit.

  The autonomous traveling robot 2 according to aspect 2 of the present invention is the autonomous traveling robot according to aspect 1, wherein the autonomous traveling robot 2 is supported on the one side in the front-rear direction with respect to the driving wheel 24 and is rotatable on one side supported by the base body (frame 10). A wheel (front driven wheel 13) is further provided, and the other side auxiliary wheel (rear driven wheel 14) and the one side auxiliary wheel (front driven wheel 13) are provided with an elastic body (frame 10) on the base body (frame 10). It is preferably suspended by compression springs 15 and 16).

  As a result, when the autonomous traveling robot starts, etc., when the autonomous traveling robot falls backward and rotates around the grounding point of the other side auxiliary wheel, or when the autonomous traveling robot suddenly stops, the grounding point of the one side auxiliary wheel is centered. When the autonomous traveling robot falls forward and falls, the load applied to each contact point is alleviated by each elastic body.

  As a result, it is possible to prevent the autonomous mobile robot from rotating backward and falling or rotating forward.

  The autonomous traveling robot 3 according to aspect 3 of the present invention is the autonomous traveling robot according to aspect 1 or 2, wherein the power source (motor 25 ′) has a center of gravity of the power source (motor 25 ′) greater than the center of gravity of the drive wheel 24. It is preferable that the drive unit support member (trailing arm 20) is mounted on the drive unit support member so as to be positioned on one side in the front-rear direction.

  Thereby, the position of the center of gravity of the combined gravity of the drive wheel, the drive unit including the power source, and the drive wheel support member can be brought to the front as much as possible.

  As a result, when the autonomous traveling robot is started, the counter-rotation moment due to the combined gravity of the drive wheel, the drive unit including the power source, and the drive wheel support member that resists the rotation moment that rotates the base body backward can be increased. .

  Accordingly, it is possible to prevent the autonomous traveling robot from rotating backward and falling when the autonomous traveling robot starts.

  The autonomous traveling robot 4 according to aspect 4 of the present invention is the autonomous traveling robot according to aspect 1, 2, or 3, wherein the drive unit support member (trailing arm 20) is supported by the base body (frame 10) so as to be movable in the front-rear direction. As the drive unit support member (trailing arm 20) contracts to the base body (frame 10) on the other side in the front-rear direction, the drive unit support member (trailing arm 20) is moved back and forth. It is preferable that a contracting movement member (plate cam 26) to be moved to one side is provided.

  Thereby, when the autonomous traveling robot starts, the driving wheel support member equipped with the driving unit including the driving wheel and the power source moves to the front side. As a result, between the position of the center of gravity of the combined gravity of the drive wheel, the drive unit including the power source, and the drive wheel support member, and the grounding point of the other auxiliary wheel that becomes a fulcrum when the autonomous traveling robot rotates backward The distance increases.

  As a result, when the autonomous traveling robot is started, the counter-rotation moment due to the combined gravity of the drive wheel, the drive unit including the power source, and the drive wheel support member that resists the rotation moment that rotates the base body backward can be increased. .

  Accordingly, it is possible to prevent the autonomous traveling robot from rotating backward and falling when the autonomous traveling robot starts.

The autonomous mobile robot 5 according to the fifth aspect of the present invention is the autonomous mobile robot according to any one of the first to fourth aspects, wherein the drive unit support member (trailing arm 20) is located below the base body (frame 10). Is supported by an elastic member (compression spring 21) so as to be vertically expandable and contractible on the base (frame 10), and the total weight of the autonomous mobile robot is M (kg) and the gravitational acceleration is g. (Ms ⁻² ), the climbing ability is θ (°), the friction coefficient is μ _k , the combined weight of the drive unit DR and the drive unit support member (trailing arm 20) is W (N), and the drive unit support member the displacement of the elastic member (compression spring 21) in the basic position in the (trailing arm 20) [Delta] y _p, the elastic coefficient of the elastic member and k (N / mm), the drive unit supporting member (trailing When over arm 20) rotation is the center rotation axis of (the distance from the shaft 12) to the point of application of the elastic member (compression spring 21) set to d _{k (mm),}
Mgsin θ <μ _k (ΣW cos θ + Σ _k (Δy _p + d _k θ (π / 180))) <Mg cos θ
It is preferable to satisfy the relationship.

  Note that the basic posture of the drive unit support member refers to the posture of the drive unit support member in a state where an external force in the horizontal direction is not applied to the autonomous traveling robot installed on the plane.

  As a result, when the autonomous traveling robot moves to a raised terrain or a depressed terrain, it can be prevented from rotating and overturning, and traveling stability can be improved.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an autonomous traveling robot that prevents a fall due to an inertial force or an external force when controlling movement and enables stable traveling on a raised terrain or a depressed terrain.

1 autonomous traveling robot 2 autonomous traveling robot 3 autonomous traveling robot 4 autonomous traveling robot 5 autonomous traveling robot 10 frame (base)
10a Rod hole 10b Frame structure 10c Front frame 11 Shaft holder 11 'Shaft holder 11a Shaft holder hole 12 Shaft (rotating shaft)
13 Front driven wheel (one side auxiliary wheel)
13a Front driven axle (wheel axle)
13b Grounding point 14 Rear driven wheel (the other side auxiliary wheel)
14a Rear driven axle (wheel axle)
14b Grounding point 15 Compression spring (elastic body)
16 Compression spring (elastic body)
17 Linear Shaft 18 Compression Spring 20 Trailing Arm (Driver Support Member)
20a long hole 21 compression spring (elastic member)
21 'compression spring (elastic member)
22 Rod 22a Clasp 22b Stopper 22c Stopper 23 Drive wheel mounting part (drive part)
23a Drive wheel mounting part hole 24 Drive wheel (drive part)
24a Drive wheel axle (wheel axle)
24b Ground point 25 Motor (power source, drive unit)
25 'motor (power source, drive)
26 Plate cam (moving member when contracted)
DR drive unit G Center of gravity (combined center of gravity)
W Synthetic gravity

Claims (4)

A substrate;
On one side in the front-rear direction on the lower side of the base, it is pivotally supported on the base by a rotary shaft, and on the other side in the front-rear direction on the lower side of the base, it is supported by the base so as to be vertically extendable. A drive support member;
A drive unit including a rotatable drive wheel mounted on the drive unit support member, and a power source mounted on the drive unit support member to drive the drive wheel;
A rotatable auxiliary wheel supported by the base body at least on the other side in the front-rear direction than the driving wheel,
The combined center of gravity of the drive unit and the drive unit support member exists at a position lower than the rotation axis of the drive unit support member ,
The drive unit support member is supported by the base body so as to be movable in the front-rear direction,
An autonomy moving member is provided that moves the driving unit support member to one side in the front-rear direction in accordance with contraction of the driving unit support member on the other side in the front-rear direction. A traveling robot. On the one side in the front-rear direction than the drive wheel is further provided with a rotatable one-side auxiliary wheel supported by the base body,
The autonomous traveling robot according to claim 1, wherein the other side auxiliary wheel and the one side auxiliary wheel are suspended from the base by an elastic body.   The power source is mounted on the drive unit support member so that the center of gravity of the power source is located on one side in the front-rear direction with respect to the center of gravity of the drive wheel. Autonomous traveling robot. The drive unit support member is supported by an elastic member on the other side in the front-rear direction on the lower side of the base body so as to be vertically stretchable on the base body,
The total weight of the autonomous mobile robot is M (kg), the acceleration of gravity is g (ms-2), the climbing ability is θ (°), the friction coefficient is μk, and the combined weight of the drive unit and the drive unit support member is W ( N), where the displacement of the elastic member in the basic posture of the drive unit support member is Δyp, the elastic coefficient of the elastic member is k (N / mm), and the rotation axis that is the rotation center of the drive unit support member is When the distance to the action point of the elastic member is dk (mm),
Mgsinθ <μk (ΣWcosθ + Σk (Δyp + dkθ (π / 180))) <Mgcosθ
The autonomous mobile robot according to any one of claims 1 to 3, characterized in that satisfies the relationship.

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