JPH05138555A - Control method for movable robot - Google Patents

Abstract

PURPOSE:To provide a control method for a movable robot so that the robot can surely move even if the condition of a contacting ground surface is unstable. CONSTITUTION:Using a movable robot 1 which has as a leg part 2 a cylindrical elastic body whose internal space is divided into plural pressure chambers by axially extended partition walls 5, 6 and 7, the pressure of fluid supplied to the pressure chambers is controlled so that the movable robot 1 is moved by the revolution of the tips of the leg part 2 around its center axis (x). Since the movable robot 1 keeps contact with a ground surface not with the ends of its leg part 2, but with the side area of the leg part 2 elastically deformed, the robot can be moved easily even when the condition of ground surface is not stable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile robot which moves by driving legs.

[0002]

2. Description of the Related Art Recently, a mobile robot having a plurality of legs and moving by controlling the movement of the legs has been actively researched. The mobile robot is characterized by being able to move without being affected by the unevenness of the road surface, and has the advantage of being much more stable than moving means using wheels. There is. Therefore, it is expected as a means of transporting people and goods in the future.

For such mobile robots, movement control according to the number of legs has been studied. In particular, in a movement control with a small number of legs such as two legs or four legs, there is a limit to the relationship between the position of the center of gravity of the robot and the driven legs, so advanced control such as moving the position of the center of gravity of the robot is also required. Has been done.

However, in any of the mobile robots, the movements of the legs are Tomovic 'and McGh.
It still uses the following form proposed by ee. That is, as shown in FIGS. 13 (a) to 13 (i), at least two joints are attached to the leg, and the movement operation is realized by cooperatively controlling the rotation angles of these joints.

In FIGS. 1A to 1C, the "kick leg" operation is performed by rotating only the first joint 51 in the clockwise direction while fixing the second joint 52. Next, the same figure (d) ~ (f)
Then, by rotating the first joint 51 in the counterclockwise direction and rotating the second joint 52 in the clockwise direction, the "raising leg" operation is performed. In FIGS. 9 (g) to 9 (i), the "lower leg" operation is performed by rotating the second joint 52 in the counterclockwise direction while fixing the first joint 51.

As described above, in the case of FIG. 13, the legs are driven and the robot moves by repeating "fixing", "clockwise rotation", and "counterclockwise rotation" for each joint 51, 52.

In other words, the leg of the mobile robot is required to have a drive stroke and a return stroke having both vertical and longitudinal movements of the leg, as schematically shown in FIG.

On the other hand, there has been proposed a mobile robot shown in FIG. 15 which uses, as a leg, a cylindrical elastic body whose inside is divided into a plurality of pressure chambers by a partition wall extending in the axial direction (Japanese Patent Application No. 2003-242242). See No. 2-177312). According to the mobile robot having such a configuration, only by adjusting the pressure to each pressure chamber,
A drive stroke and a return stroke required for movement are realized. Therefore, the robot can be easily moved without requiring complicated control such as cooperative control of two joints.

[0009]

However, the movement control of the mobile robot shown in FIG. 15 is based on the control of a rigid link. Therefore, as shown in FIG. 13, the legs cannot move unless the tips of the legs are surely brought into contact with the ground. Further, since the height difference between the legs during standing and free leg depends only on the axial expansion and contraction of the tubular elastic body forming the legs, a very large height difference cannot be obtained. In other words, it is difficult to move the robot when the state of the ground contact surface is not stable, such as when moving on a highly undulating ground or when moving a muddy area. Therefore, an object of the present invention is to provide a control method for a mobile robot that can reliably move even if the state of the ground contact surface is unstable.

[0010]

In order to achieve the above object, in the present invention, a moving means is a cylindrical elastic body whose inside is divided into a plurality of pressure chambers by a partition wall extending in the axial direction. In a method of controlling a mobile robot that uses a mobile robot to move the mobile robot by controlling the pressure of a fluid supplied to the pressure chamber, the pressure chamber is configured so that the distal end of the tubular elastic body revolves around an axis. It is characterized in that the pressure of the fluid supplied to is controlled.

[0011]

As described above, if the distal end of the tubular elastic body is revolved around the axis, the mobile robot does not always contact the ground at the distal end of the tubular elastic body, but the tubular elastic body is elastically deformed and the side surface portion is deformed. It may be in a state of being grounded at. Therefore, there is no restriction that the tip of the cylindrical elastic body must be in contact with the ground when moving, and the robot can be easily moved even when the condition of the contact surface is not stable. is there. In addition, since the height difference between the legs when standing and when swinging depends not only on the axial expansion and contraction of the cylindrical elastic body but also on the amount of bending, the height difference can be made large, and the uneven surface It can also be used for moving rough terrain such as stairs and stairs. Further, by using the control method of the mobile robot of the present invention, not only the movement on the ground but also the swimming of the robot in water can be performed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view of a mobile robot showing a first embodiment of the present invention, FIG. 2 is a side view of the mobile robot, and FIG. 3 is a plan view of the mobile robot. The mobile robot 1 according to this embodiment has four legs (moving means) 2 (2a to 2d), which are arranged at the four corners of the base 3, respectively.

As shown in FIGS. 2 and 3, the base 3 is formed by bending four tips 3a of a substantially cross-shaped member at an angle α (here, 45 °) with respect to the center 3b thereof. ..
Each tip 3a is provided with a hole into which the leg 2 is fitted,
An outer portion of a sealing portion 10 (described later) formed on the upper portion of the leg portion 2 is clamped and fixed by screws. As a result, the tips of the four fixed leg portions 2 are set to be spread radially at equal intervals.

FIG. 3 shows the fixed state of the legs 2a to 2d with respect to the base 3. As shown by the broken lines in the figure, each of the legs 2a to 2d has three partition walls 5, 6, 7 inside thereof.
Is formed so as to extend in the axial direction. Further, the legs 2a to 2d are, as shown in FIG.
Are arranged so that the extension surfaces of the partition walls 5 of the leg portions 2a to 2d intersect at the central portion of the. The center of gravity of the mobile robot 1 is designed to match the center of the base 3, that is, the center of gravity. Next, the leg portions 2a to 2d will be described in detail.

As shown in the exploded perspective view of FIG. 4, the leg portion 2 has a cylindrical elastic body 8 forming an outer wall, a tip sealing portion 9, a root sealing portion 10, and a tube 11 (11a, 11b, 11c). And tip member 12
It consists of As can be seen from the figure, the tubular elastic body 8 is integrally formed by bonding three unit tubular elastic bodies 13 (13a, 13b, 13c) having the same shape in parallel in the axial direction. Is. Therefore, the elastic partition wall 5 is extended in the axial direction of the cylindrical elastic body 8 by the bonded portion, and the elastic partition wall 5 forms three pressure chambers 14, 15, and 16.

As shown in FIGS. 4 and 5, the unit cylindrical elastic bodies 13a, 13b, 13c are made of elastic material made of fibers 17 spirally wound at intervals close to each other in the direction perpendicular to the drawings. It is formed by coating with, for example, silicone rubber. Therefore, the tubular elastic body 8 is formed of an anisotropic elastic material made of a composite of fibers 17 and rubber, so that the direction in which the longitudinal elastic modulus is small substantially coincides with the axial direction 18 of the tubular elastic body 8. It tends to stretch in direction 18. Further, in the direction 19 which is orthogonal to the axial direction 18, the fibers 17 make it difficult to stretch because of a large longitudinal elastic modulus.

The tip sealing portion 9 is a fan-shaped upper lid 9a, 9b, for sealing the pressure chambers 14, 15, 16 formed in the unit cylindrical elastic bodies 13a, 13b, 13c made of metal or the like. One end of 9c is inserted into the unit cylindrical elastic bodies 13a, 13b, 13c and bonded.

The root sealing portion 10 includes fan-shaped lower lids 10a, 10b, 10c similar to the tip sealing portion 9 and the lower lids 10a, 10b, 10c.
It is constructed by inserting one end of c into the unit cylindrical elastic bodies 13a, 13b, 13c and adhesively sealing it.

Further, the lower lids 10a, 10b, 10c are provided with insertion holes 20a, 20b, 20c into which the tubes 11a, 11b, 11c are inserted and fixed, respectively. The tubes 11a, 11b, 11c are hermetically fixed to the insertion holes 20a, 20b, 20c with an adhesive. The other ends of the tubes 11a, 11b, 11c are connected to a pressure control device not shown here (for example, an air source, a pressure control valve, and a computer that controls them) so that the pressure of the working fluid can be freely adjusted. It is like this. Although not shown here, the three bonded unit cylindrical elastic bodies 13a, 13b, 13c are further covered with silicone rubber.

A tip member 12 made of silicone rubber is adhered to the tip of the tip sealing portion 9 of the cylindrical elastic body 8. The tip member 12 has a substantially spherical shape. The tip member 12 may be processed to have a relatively large surface friction coefficient.

The operation of the leg portion 2 having the above structure will be described with reference to FIG. For example, it is assumed that the working fluid is sent from the tube 11a to increase the pressure in the pressure chamber 14. In this way, the pressure chamber 14 extends in the axial direction, and the tubular elastic body 8 is curved in the A direction and is in the state shown by the chain line. Then, if the pressure of the pressure chamber 16 is further increased via the tube 11c in this state, the tubular elastic body 8 is curved in the B direction.

In this way, by combining the pressures applied to the three pressure chambers 14, 15 and 16, the tubular elastic body 8 can be bent in any direction. Also, the three pressure chambers 14,1
If the pressures of 5 and 16 are increased equally, the cylindrical elastic body 8 will move in the axial direction 18
It can be straightened out. In this way, by controlling the pressures of the three pressure chambers 14, 15, 16 by utilizing the characteristics of the anisotropic elastic material, the tubular elastic body 8 can be simultaneously bent and expanded.

As the cylindrical elastic body 8, the unit cylindrical elastic bodies 13a, 13b and 13c wound with fibers are adhered and covered with silicone rubber, but the fibers are wound. It is also possible to use a unit in which a unit cylindrical elastic body which has not been bonded is wound, fibers are entirely wound, and then coated with silicone rubber. In addition, the cylindrical elastic body 8 is provided without using the tip sealing portion 9.
Alternatively, the tip member 12 may be directly joined. Further, the root sealing portion 10 can be integrally molded with silicone rubber instead of metal.

Next, the movement control method of the mobile robot of the present invention configured as described above will be explained. The mobile robot of the present invention is characterized by driving the legs 2 in three dimensions. This point is significantly different from the conventional control of FIG. 13 in which the legs are driven two-dimensionally.

FIG. 7 is a diagram showing a deformed state of the leg portion 2 of the mobile robot 1. As shown in FIG. 3A, the leg portion 2 is curved and controlled so that its tip portion revolves around the central axis x. Then, the movement is realized in a state in which the four legs 2a to 2d are, for example, 90 degrees out of phase with the revolution.

FIG. 8 is a diagram showing the positional relationship of the tip ends of the legs when the legs 2 are in the orbiting motion.
Reference numeral 10 is a graph showing the state of pressure applied to the pressure chambers 14, 15, 16 of the leg portion 2. In FIG. 8, (g) is all pressure chambers 1
4, 15 and 16 are in a state where they are evenly pressed (or not pressed), which shows a state in which the leg 2 is stretched in the direction of the central axis x. The state (g) is the initial state.

First, as shown in the area A of FIG. 10, the two pressure chambers 15 and 16 are controlled to be uniformly pressurized. Then, the pressure chambers 15 and 16 extend more than the pressure chamber 14, and as a result, the leg 2 is curved as shown in (a). Next, as in the region B, the pressure in the pressure chamber 15 is stopped and only the pressure chamber 16 is pressurized. Then, the bending direction moves by about 60 °, and the deformed state as shown in (b) is obtained. In this way, when the pressure control according to the regions C to F in FIG. 10 is performed, the legs 2 are sequentially (c) to
The deformation state of (f) is realized.

That is, the pressure chambers 14, 15 and 16 of the leg 2 are shown in FIG.
If a pressure state such as
The rotary motion as shown in FIG. 8 is realized. Then, the robot 1 moves in the direction of the arrow.

In the state where the leg portion 2 is in the state (d), the leg portion 2 comes into contact with the ground to serve as a supporting leg, so that the weight of the robot acts as a load. In such a state, the leg portion 2 made of an elastic body is elastically deformed as shown in FIG. 7B due to its weight, and comes into contact with the ground on the side surface of the leg portion. That is, the support leg is shaped so that its side surface contacts the ground.

Therefore, when moving, the tip of the cylindrical elastic body does not come into contact with the ground unlike the conventional case, so that the robot can be easily moved even in an environment in which the state of the contact surface is not stable. .. This makes leg 2
A drive stroke and a return stroke are realized, and propulsion force for movement can be obtained.

In this embodiment, (a), (c) and (e) are two chamber pressurization, and (b), (d) and (f) are one chamber pressurization. The amount of bending (and total leg length) is (b), (d), rather than (a), (c), (e)
(f) is larger. (See FIG. 9.) Therefore, it cannot be said that the drive stroke and return stroke realized in the leg 2 change smoothly, but for example, the method of changing the pressure state in an analog manner as shown in FIG. 10 is adopted. Then, it is possible to easily change the drive stroke and the return stroke smoothly. In order to change the pressure state in an analog manner, a pressure proportional valve may be used instead of the electromagnetic switching valve (on-off valve).

Further, the pressures of the pressure chambers 14, 15 and 16 are controlled so that such a series of operations are continuously performed so that the center of gravity of the mobile robot 1 comes inside the grounded leg. If the four legs 2 are driven in a proper order with a proper phase difference, a stable movement operation is realized.

As described above, in the present invention, the pressure is controlled so that the tips of the leg portions 2 revolve around the central axis x. Therefore, when the leg portion 2 becomes the supporting leg, the leg portion 2 is elastically deformed and comes into contact with the ground on its side surface. Therefore, when moving, the tip of the tubular elastic body does not come into contact with the ground unlike the conventional case, so that the robot can be easily moved even in an environment in which the state of the contact surface is not stable.

Further, since the predetermined angle α is provided between the leg portion 2 and the base 3, the area of the side surface of the leg portion where the leg portion 2 comes in contact with the ground is increased, and more stable movement is possible. Becomes Next, a second embodiment of the present invention will be described with reference to FIG. The difference of this embodiment from the above embodiments is that not all the pressure chambers are pressurized but only a specific pressure chamber is pressurized.

First, as shown in the area A of FIG. 11, the two pressure chambers 15 and 16 are controlled to be uniformly pressurized. next,
As in the region B, the pressure in the pressure chamber 15 is stopped and only the pressure chamber 16 is pressurized. The process up to this point is the same as in the above embodiment.
Here, in this embodiment, the state of FIG. 8 (g) is realized by stopping the pressurization of all the pressure chambers 15, 16 and 17. (g)
11 is set to be three times as long as the state of A or B is maintained in FIG. 11 (this is the same as (c), (d), (e) in the first embodiment). However, it may be arbitrarily set as long as it is within a range in which a stable walking motion can be obtained. Finally, pressurize only the pressure chamber 15 (f)
It transforms like.

Even if such a control method is adopted, the robot 1 can still be moved. Further in FIG.
Since the states of (c), (d), and (e) are omitted, the robot 1
When the robot moves, the tip of the leg 2 does not enter toward the center of the robot 1 (Fig. 7 (c)). As a result, the vertical movement of the mobile robot 1 is alleviated, and the stability when the robot 1 moves is significantly improved.

Next, a concrete example for realizing the pressure control of the leg portion 2 shown in FIGS. 10 and 11 in an analog manner will be described. When analog control is performed using a pressure proportional valve, etc., when the deformation of the leg portion 2 is small, follow the equation below, which is approximately determined by the balance of the bending moment and the position of the tip of the leg 2 in the positive cross section. Thus, pressure control can be easily performed.

[0038]

[Equation 1] That is, the movement of the tip portion (tip member 12) of the leg portion 2 is determined by the bending direction θi of the leg portion 2, the axial length Zi, and the parameter Ki indicating the amount of bending. For example, when Ki is 0, the leg 2 does not bend but only expands and contracts in the axial direction 18.
The larger the Ki, the larger (deeply) the leg 2 bends.

FIG. 12 shows an example of the pattern of Ki, θi, Zi for obtaining the pressure Pi applied to each pressure chamber 14, 15, 16 in order to realize the deformed state shown in FIG. 8 for the mobile robot 1. And the horizontal axis represents time.

A feature of the present invention is that the moving direction of the tip portion of the leg portion 2 does not face a fixed direction when viewed from the traveling direction of the robot 1. That is, when controlling a conventional mobile robot, only Ki and Zi need be controlled, but in the present invention, .theta.i must be newly added as a variable.

According to this control method, the tips of the legs 2 can be completely moved circularly. However, since the robot 1 moves even if the complete circular movement is not realized, control may be performed according to the change in this graph. For example, Figure 12 (a), (b),
Instead of controlling (c), (a), (b), (d), that is, Zi
Alternatively, Zi 'may be adopted. In this case leg 2
Although the tip end of the movement becomes a movement close to an elliptic movement, the proportion of the stance phase in one stroke increases, and a more stable movement movement is realized. Further, by reversing the rotation direction of the legs 2, the robot 1 can be easily moved backward.

Further, when the robot is viewed from the traveling direction of the robot, if the leg portion attached to the right side of the base and the leg portion attached to the left side of the base are rotated in opposite directions, the robot rotates around its center of gravity. .. Using this principle, the robot can be easily turned in any direction. The present invention has been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, the bending angle α of the tip portion 3a of the base 3 is not limited to 45 °, but it is preferable to arbitrarily set it according to the length and rigidity of the leg portion 2. Similarly, the tips of the four legs 2 are equally spaced (the quadrangles formed by the tips are square).
However, the shape may be any rectangle such as a rectangle. Also,
The present invention is not limited to a four-legged mobile robot, but has two legs or five.
The present invention can be applied to a mobile robot having more than legs and has the same operational effect.

Further, according to the control method of the mobile robot of the present invention, it is possible not only to simply move the mobile robot on the ground but also to make the robot swim underwater. For example, if the plane that extends in the direction perpendicular to the plane of the paper including the central axis x in FIG. 9 is the waterline, the legs 2 act as oars of the boat and move while performing the operation of webbing. The leg 2 does not rust like metal,
Since it is driven by fluid pressure and electricity is not used, it is suitable for movement in water.

[0045]

As described above, according to the present invention, the tip of the tubular elastic body revolves around the axis. Therefore, in the mobile robot, the cylindrical elastic body is not elastically grounded at the tip end thereof, but the cylindrical elastic body is elastically deformed and grounded at the side surface portion. Therefore, it is not necessary to contact the tip of the cylindrical elastic body with the ground when moving, and the robot can be easily moved even when the state of the ground contact surface is not stable.

[Brief description of drawings]

FIG. 1 is a perspective view of a mobile robot according to a first embodiment of the present invention.

FIG. 2 is a side view of the mobile robot according to the first embodiment of the present invention.

FIG. 3 is a plan view of the mobile robot according to the first embodiment of the present invention.

FIG. 4 is an exploded perspective view of legs of the mobile robot according to the first embodiment of the present invention.

5 is a cross-sectional view of the leg portion shown in FIG.

FIG. 6 is an overall perspective view of the leg portion shown in FIG.

FIG. 7 is a view showing a deformed state of legs.

FIG. 8 is a view showing a positional relationship between the tip ends of the legs when the legs are revolving.

FIG. 9 is a diagram comparing the deformed states of the legs when the number of pressure chambers to be pressurized is different.

FIG. 10 is a graph showing a state of pressure applied to each pressure chamber of the leg portion.

FIG. 11 is a graph showing a state of pressure applied to each pressure chamber of the leg portion.

FIG. 12 is a graph showing an example of patterns of K _i , θ _i , and Z _i .

FIG. 13 is a diagram showing a moving form of a general mobile robot.

FIG. 14 is a diagram showing a movement cycle required for a mobile robot.

FIG. 15 is a perspective view showing a conventional mobile robot.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mobile robot 2 ... Leg part (moving means) 3 ... Base 5, 6, 7 ... Partition wall 8 ... Cylindrical elastic body 11 ... Tube 13 ... Unit cylindrical elastic body 14, 15, 16 ... Pressure chamber

Claims (1)

[Claims] 1. A mobile robot having a cylindrical elastic body whose inside is divided into a plurality of pressure chambers by a partition wall extending in the axial direction as a moving means, to control the pressure of a fluid supplied to the pressure chambers. In the control method of the mobile robot for moving the mobile robot according to, the control of the mobile robot is characterized in that the pressure of the fluid supplied to the pressure chamber is controlled so that the tip of the cylindrical elastic body revolves around the axis. Method.