JP2005144582A - Tetrapodal traveling machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tetrapodal traveling machine for realizing a moving shape such as a gallop, a trot, a pace and a bound (a jump) with a further simple mechanism. <P>SOLUTION: A front leg thigh upper part 110, a front leg thigh lower part 111, a rear leg thigh upper part 112 and a rear leg thigh lower part 113 of this tetrapodal traveling machine, are respectively composed of a four-node link mechanism. A cut line is formed in a pedestal 121 of a body, and front and rear pedestals are connected by a flexible beam 120. The front leg thigh upper part is supported by the front pedestal, and the rear leg thigh upper part is supported by the rear pedestal so as to be respectively rotatable. A link mechanism being a thigh upper part of respective front legs and rear legs, is driven by a driving device 130. At this time, a walking shape can be varied by changing a phase of the front legs and the rear legs. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a four-leg running machine that performs four-leg running.

  Currently, most robots are for industrial use, and are specialized in certain parts of the human motor functions. For example, an arm robot that performs metal welding or attaches parts to a manufacturing machine is well known, and has become a very common robot in the industry.

  With the miniaturization of computers, the development of IC technology, and the emergence of various sensors, robots are becoming more humanized and animalized. Humanization and animalization are robots that mimic humans and animals rather than robots that have exactly the same form and function as humans and animals. For example, the robot is a biped robot that is the same as a human, or a robot that walks on four legs, such as a dog or a cat. Also, by giving emotions to robots (expressing emotions with anger when tapped and delighted when stroked), toys that appear to be like pets have also appeared.

  Some moving means use wheels. In all trains, cars, bicycles, etc., the rotational movement of the wheels is changed to the movement movement of the car body such as a straight line, curve, or circle. The movement of the vehicle body by wheels is not suitable for moving on uneven surfaces such as depressions and stairs or on the floor. In this respect, biped walking and quadruped walking of animals are highly adaptable to floors with steps such as stairs. It is human desire to make robots realize the same form as humans and animals (especially walking and running). Of course, it is also a desire to realize a robot that enables movement methods and actions that cannot be moved by wheels.

  When a person walks, put your right foot forward and at the same time swing your right hand back and your left hand forward. That is, the right foot and left hand, and the left foot and right hand move in the same direction. If you become crawl on all fours and move the limbs as they are, you will be walking a quadruped animal. The action of walking is an action of moving with either foot on the ground. Even when a quadruped animal runs, it is basically an extension of the movement of walking. In the case of a horse, the left and right of the front legs or the left and right legs of the rear legs may be temporarily aligned in the aerial posture during competition, but the right and left legs are separate when landing. This is the same during take-off and works separately on the left and right. It is not a movement to jump together with both feet, which is said to be jumping.

  As an invention that deals with a moving device by walking on four legs, there is a “four-legged traveling device” (Patent Document 1). In the present invention, the front left and right legs and the rear left and right legs are connected to the operation part of the approximately five-bar linkage mechanism, and each operation part is operated in series by one drive source (one actuator). A gait similar to a leg animal is possible. In addition, by making the left and right legs narrow, it has a structure that allows the same steering method as a bicycle or motorbike.

  As an invention of a legged mobile robot that performs a violent motion such as running or dynamism without using a large drive mechanism having a high operating speed and a large torque, there is a “legged mobile robot” (Patent Document 2). In addition to a normal drive mechanism such as an actuator that performs walking motion, it is equipped with a power storage mechanism composed of a mainspring, flywheel, etc., enabling instantaneous operation by releasing the stored power instantaneously Yes.

  As an invention of a legged mobile robot that performs various legged motions such as crawling, bounces, gallops, and trots, there is a “legged mobile robot and leg mounting structure” (Patent Document 3). By attaching a coil spring between the body part and the upper leg part, a force larger than the driving force of the actuator is obtained, and an operation requiring an instantaneous force such as a sway is possible. Moreover, the impact force at the time of landing is relieved by the spring. By mounting an upper link and a lower link that can rotate around the connection part of the body part in parallel to the body part and the base of the leg part, the rotational movement is changed to the vertical movement of the leg part, so that walking and running are possible. It is possible. At this time, a lateral blur occurs due to the rotation of the link, but by making the length of each link sufficiently longer than the width of the vertical movement, the lateral blur can be ignored.

  In “Robot Device and Jump Control Method of Robot Device” (Patent Document 4), legs of a four-point link mechanism (four-bar link mechanism) are employed. The ends of the two connecting rods (link rods) constituting the four-point link mechanism in the body direction are connected by a rotation support shaft, and the other end is connected to a connecting member (a part that becomes a knee joint). The connecting member is connected to a rod having a coil spring and a leg (rod-like member) connected to the foot. A contact sensor is attached to the tip of the rod-like member that becomes the foot, and it can be determined whether the foot is floating or is landing by the signal of the contact sensor. In addition, sensory functions similar to those of humans are reproduced by analyzing signals from touch sensors, distance sensors, microphones, CCDs, etc. using integrated circuits. In particular, it is noted that the expression of emotions by learning function is also adopted as part of the robot motion. The rotational movement of the rotary spindle is converted into a linear movement of the rod-like member by a four-point link mechanism. In addition, by using a servo motor as the driving force, it is possible to rotate freely according to the command of the control unit, and various gaits and operations are drawn out. When the robot touches the ground, the joint bends and the coil spring contracts. Therefore, as the next operation, the rod is pushed down by the elastic force in the extending direction of the coil spring, the joint (connecting member portion) is extended, and a jumping operation can be performed. This reduces the load on the servo motor.

Although used in the above example, the four-bar linkage is applied in various forms in robotics. In the above, it is described as “4-point link mechanism”. FIG. 1 shows an example of a four-joint link mechanism, and at least one joint is often fixed to a base portion. In the example of FIG. 1, when the link AB is linked to the drive unit at the node A and rotates, the length of the link bar has a relation of AB <BC <CD <AD and the link bar AB is θ ₁ degree. If the link rod CD is rotated by θ ₂ degrees by rotating, the relationship θ ₁ > θ ₂ is established. That is, it can be used when moving a large object with a small force.

FIG. 2 is an example of a four-bar linkage mechanism having a Chebyshev first approximate linear motion mechanism. It is assumed that the points A and D are fixed, and the point B can rotate around the point A. Further, when the point E on the extension of the link bar BC is assumed, the following relational expression holds.
AD = 2AB
BC = CD = CE = 2.5AB
When the point B moves circularly under this condition, a part of the locus of the point E becomes an approximate straight line as shown in the figure. This is called Chebyshev's first approximate linear motion mechanism, and is used as a legged walking mechanism of the robot.

JP-A-9-132119 JP 2001-246585 A JP 2002-103253 A JP 2003-80477 A

  In the current quadruped traveling machine (robot), the movement form (gait) is basically uniform. This is because it is difficult to freely switch the link form of the mechanical structure and reflect it in the moving form. However, the robot apparatus mentioned in the prior art can move, stop and jump. This is realized by a control device, an energy storage mechanism (using elastic energy of the material <mainly spring>), a link mechanism, a servo motor, and the like.

  The problem to be solved by the present invention is to realize a four-leg traveling machine that realizes a movement form such as gallop, trot, pace, and bound (jump) with a simpler mechanism. In terms of horse racing, gallop means assault (how to run during competition), trot means fast walking, and pace means the flow of the race, but here it is used to mean running, walking, stride (or speed), etc. In particular, when all of the legs move away from the ground, a large amount of power is required to resist gravity. Therefore, a mechanism that requires as little energy as possible is adopted.

  In order to solve the above problems, the invention according to claim 1 is a four-leg running machine capable of various gaits, wherein each leg of the machine includes an upper thigh and a four-joint link mechanism each having a four-joint link mechanism. A four-leg traveling machine having a structure in which a lower thigh having a joint is coupled by a joint portion, and a base to which a front leg is attached and a base to which a rear leg is attached is connected by a flexible member having elasticity. It is.

  The invention described in claim 2 is the four-leg traveling machine according to claim 1, wherein a mechanism for adjusting the rotation phase of each leg by changing the attachment angle of the leg link of the four-bar linkage structure. A four-legged running machine is provided.

  Each leg has a structure composed of two sets of a four-joint link mechanism in the upper thigh of the leg and a four-joint link mechanism in the lower thigh of the leg. By using a four-joint link mechanism for both the upper thigh and lower thigh legs, joint flexion and extension are realized. Along with the movement of the legs, deflection (bending) occurs in the member (beam) that connects the front legs and the rear legs. This deflection has an effect of energy storage, and when the deflection is released, a force more than the power of the actuator is generated and used as a repulsive force of the leg. In other words, this force enables operations such as bouncing.

  The rotational movement of the drive mechanism is transmitted to the four-bar link of the leg. If the four-bar linkage is the Chebyshev's first approximate linear motion mechanism, the rotational motion of the drive mechanism can be converted to approximate linear motion.

  In the present invention, various gaits are realized. For this reason, in the present invention, the rotation angles of the four-bar linkage mechanisms of the left and right legs and the front and rear legs can be changed.

  In normal animal walking, the phase difference between the paired left and right legs and the phase difference between the front and rear legs on the same side are both 180 degrees. Also, the phase difference between the left and right legs when jumping with both feet aligned is 0 degrees. These operations can also be adjusted by attaching the rotation angle of each link of the front, rear, left and right legs.

  It cannot be denied that the power from the one-actuator is insufficient for a small machine powered by a battery such as a toy. Therefore, an elastic flexible beam is installed at the top of the machine. The flexible beam is attached to the upper part of the thigh of the four-joint link mechanism, and deflection (bending) occurs with the movement of the thigh. This deflection has an effect of energy storage, and when the deflection is released, a force more than the power of the actuator is generated and used as a repulsive force of the leg. In other words, this force enables operations such as bouncing.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 3 is an assembly model of the four-leg traveling machine of the present invention. The white quadrilateral shown in the drawing forms the upper part of the four-node link mechanism thigh, and the thin white quadrilateral below it forms the lower part of the four-node link mechanism thigh.

  FIG. 4 is a schematic diagram showing an example of the machine of the present invention viewed from the left side. However, the white part (line added to the model) is the main line of the leg part used when analyzing Chebyshev's first approximate linear motion. In the quadruped running machine 1 of the present invention, the legs are configured by a front leg upper thigh 110, a front leg lower thigh 111, a rear leg upper thigh 112, and a rear leg lower thigh 113.

  As shown in FIG. 3, each part is constituted by a four-bar linkage mechanism. A pedestal 121 is installed on the legs, and a driving device 130 (usually a motor), a power source and a control device storage unit 140 are mounted thereon. In addition, a cut is made in the pedestal 121, and the front and rear pedestals are connected by a flexible beam 120. As a material of the flexible beam, a leaf spring or the like can be used. The front part 150 corresponds to the head of the animal and serves as a weight for balancing the whole. The foot part 114 (grounding part) is a part that touches the floor, and a material such as rubber is attached to prevent slipping. If you attach a pressure sensor to the bottom of this part, you can determine whether your foot is on the ground.

  FIG. 5 shows only the skeleton part extracted from the nodes of the front leg shown in FIG. The front leg is composed of a four-joint link mechanism ABCD constituting the upper thigh 110 and a four-joint link mechanism CEFG of the lower thigh 111. Nodes A and D are fixed to the pedestal, and node B rotates about node A. The nodes B, C, E and the nodes D, C, G are respectively mounted on the same link bar. As a result, when the node B passes through the lower half of the circle (the state of r1), the front legs (link ABCD, CEFG) contract, the foot 114 floats, and the foot moves in the l1 direction. On the other hand, when the node B passes the upper part of the node A (state of r2), the front legs (link ABCD, CEFG) are narrowed, the foot is released (floating), and the force in the l2 direction acts on the foot. As described above, the rotation of the node B causes the leg portion to advance by repeating the kick and the simple movement.

  Note that rt indicated by a dot in a circle in FIG. 4 represents a rotational position of a node (corresponding to B in FIG. 5), and the movement l of the foot 114 corresponding to rt is represented by a square x symbol (l1, FIG. 5). equivalent to l2). This analysis uses Chebyshev's first approximate linear motion mechanism.

FIG. 6 shows a basic way of walking for a quadruped walking animal. Solid lines Lfl and Lbl are the left leg (front side when viewed from the side) and broken lines Lfr and Lbr right leg (the back side when viewed from the side). The operation of walking is as follows.
(1) Still state. At this time, the four legs are in a grounded state (more precisely, the sole is in a grounded state).
(2) Start walking. Bend left front leg Lfl and right rear leg Lbr and move them forward. At this time, the right front leg Lfr and the left rear leg Lbl are in contact with each other and generate a force to push the body Bd forward.
(3) The state where the left front leg and the right rear leg are in contact with each other and the entire weight has moved.
(4) The left front leg and the right rear leg are in contact with the ground, and the right front leg and the left rear leg start to move.
(5) The right front leg and the left rear leg are in contact with the ground and the entire weight has moved.

  In this way, the basic motion of a four-legged walking animal is an operation in which a leg (leg) on a diagonal line is grounded to generate a propulsive force, and a leg on another diagonal line is floated and moved forward. The fact that the diagonal legs are in contact with the ground means that the body can be stabilized because the center of gravity of the body is on the diagonal line. Running is basically an extension of walking. The difference is that the movement of the four legs moving away from the ground at the same time is added. In the case of a quadruped machine, if the kicking power of the grounding leg (kicking leg) is increased, the whole body (four legs) will naturally float away from the ground.

  In order to realize the above operation, the movement of the front leg and the rear leg may be reversed. That is, the rotational phases of the front legs and rear legs (point B in FIG. 5) on the same body side surface are shifted by 180 degrees, and the rotational phases between the left and right front legs and between the left and right rear legs are also shifted by 180 degrees.

  FIG. 7 shows an example in which a front leg link and a rear leg link on the same side are attached to the same rotation shaft of the actuator. In this case, since the phase difference between the rotation angles of the front and rear leg links (the difference in rotation between B and B) is 0 degrees, the phase difference is set to 180 degrees (the front legs and the rear legs by making the link attachments line-symmetric). The movement of the leg is reversed). In this figure, ABCD is the four-node link mechanism of the upper front leg thigh, A'B'C'D 'is the four-node link mechanism of the upper rear leg thigh, and CEFG is the four-node link mechanism C'E'F'G of the lower front leg thigh. 'Is a four-joint link mechanism in the lower leg thigh. C and C ′ constitute a joint that connects two four-joint link mechanisms.

  A and A ′ and B and B ′ are nodes attached at the same position (hereinafter, A ′ and B ′ are represented by A and B, respectively). The four-node links of the upper and lower thighs of the front leg and the upper and lower thighs of the rear leg are attached symmetrically with each other (however, the link sizes are not necessarily the same). Thereby, the following operations can be realized.

  By the rotation r of the node B, the force f1 acts on the link bar BC, the nodes C and G are pulled in the direction of the arrow (rearward), the node F is pushed upward, the foot 114f floats, and the foot Move in the direction of l1 (forward). On the other hand, in the rear leg, the rotation r causes a force of f2 (= f1) to act on BC ′, the nodes C ′ and G ′ are pushed backward, and the node F ′ is pushed down (in the direction of the arrow) to the foot. 114b is grounded, and a force in the direction l2 (rear) is applied to the foot. As a result, the body Bd can move forward.

  When the rotation r of the node B is reversed, that is, in the direction D in the figure, the front foot is grounded and a rearward force (kick force) is generated, and the rear foot is floated and moves forward (in this case) (The figure is omitted). The movement of the actual link is not as simple as described above, but the bottom line is that if the upper link narrows, the lower link also narrows and the leg length becomes longer, the foot touches down, and the upper link widens, the lower part The link also spreads, the leg length becomes shorter, and the legs float.

  In the case of slow motor rotation, walking is performed, but as the rotation speeds up, the kicking force increases and all four legs move away from the ground. It shifts to the so-called running state. Depending on the speed of rotation, the canter (slow running) and gallop (running) in horse racing can be reproduced.

  However, since a small four-legged traveling machine such as a toy has a limit in power, another device is required for the operation of floating the whole body such as bouncing. Also, some energy storage device is required to reduce the load on the power source. FIG. 8 is another example for explaining the operation of the front legs and the rear legs in the embodiment of the four-leg traveling machine of the present invention.

  FIG. 9 shows an example in which the link between the front leg and the rear leg on the same side is driven by another actuator. FIG. 10 shows an example of a structure in the case where the system of FIG. 9 is driven by one motor.

  FIG. 11 shows an example of attaching a flexible beam. (1) and (2) are examples in which the pedestal 121 is divided into front and rear and connected by a flexible beam 120. (1) is partially connected, and (2) is partially connected to the left and right. In normal walking and running, the left and right legs move in the opposite direction, so the left and right flexible beams move in the opposite direction. Accordingly, the separation as in (2) is superior in the function as a spring. However, in either case, since it is directly attached to the pedestal 121, it causes vibrations in the pedestal. Since an actuator, a control device, and the like are mounted on the pedestal, this vibration is not preferable. Therefore, in the example of (3), the base 121 and the flexible beam mounting bases 121l and 121r are separated, and the flexible beam 120 is attached to the flexible beam mounting base. In this way, the pedestal is not easily affected by the expansion and contraction of the flexible beam, and the left and right flexible beams can operate independently.

  FIG. 12 shows the function of the flexible beam. (1) is at rest. The flexible beam 120 is horizontal with the mounting base 121l. (2) is when the front and rear legs 114f and 114b are closed, and the flexible beam bends. At this time, force f acts on the mounting base 121l in the vertical direction by the elastic force (restoring force) of the flexible beam. When this horizontal force f ′ opens the leg, it is added to the driving force F of the driving measure, and a larger leg force can be generated as in (3) (in the figure, r is due to the elastic force of the flexible beam). Shows the direction of movement of the mounting base). The material of the flexible beam is preferably a strong material having a high elastic coefficient such as a leaf spring.

  Gait can be changed by changing the mounting angle of the front, rear, left and right legs. For example, in the case of the gait shown in FIG. 6, the phase difference between the left and right legs is 180 degrees. As shown in FIG. 13 (1), when the machine is viewed from the side, the positional relationship between the left leg node Bl and the right leg node Br is attached to a position opposite to the rotation circle. For this reason, the direction of movement of the front and rear legs is reversed with respect to the rotation r of the nodes Cl and Cr. (2) is a case where the phase difference is θ degrees (<180 degrees), and the displacement of the movement of the nodes Cl and Cr is small. If θ is 0 degree, there is no phase difference between the right leg and the left leg, the left and right legs move in the same direction, and a jump-like action is obtained.

  Table 1 below shows experimental results of examining changes in the average moving speed of a quadruped traveling machine due to the rotational speed and phase difference of the motor. If the rotational speed (angular speed) of the motor increases, the average moving speed also increases. This is easy to imagine. On the other hand, the average moving speed due to the phase difference is the fastest when the phase difference is 0 degrees and the slowest when it is 90 degrees when compared at the same rotational speed. This is because the phase difference is 0 degree, that is, the driving method that kicks with both feet at the same time produces the largest driving force. When the phase is 90 degrees, the stride of the left and right legs is narrower than normal (when the phase difference is 180 degrees), Since the timing of kicking the left and right legs is halfway, it can be estimated that the speed will be slow. In any case, the experimental results in Table 1 indicate that various ways of walking (or running) and speeds can be created by changing the phase difference.

  In the machine of the present invention, the leg is composed of the upper thigh and lower thigh of the four-bar linkage mechanism, and the joint of the animal's leg can be reproduced at the joint part of the upper thigh and lower thigh. Can be expressed. Moreover, since the phase difference can be adjusted depending on the mounting positions of the front, rear, left and right legs, there is an advantage that the gait can be easily changed. As a result, operations such as normal walking, jumping, jumping, running, and running can be easily realized.

  When the quadruped traveling machine of the present invention is applied to a toy, the motor is small in terms of power, so there is a limit in power with one motor. Therefore, in the present invention, by attaching a flexible beam, a force obtained by adding the elastic force of the flexible beam to the force obtained from the power source can be extracted. As a result, it is possible to perform an exercise that requires an impulsive force such as bouncing. It also plays a role in reducing the load on the power source.

  In the present invention, the sensor and the control device have not been described, but by adding these functions, a full-fledged animal robot can be realized. For example, by sending a command such as a gallop or a trot to the control device, the driving force of the actuator can be changed or the phase difference can be changed mechanically. In addition, a force sensor (ground pressure sensor) is attached to the sole of the foot, and the control device automatically determines the running state of the machine based on the signal of the force sensor to determine whether it is walking or running. it can. In combination with a visual sensor, a speed sensor, etc., it is also possible to correct the operation by feeding back the signal of each sensor to the control device and correcting the difference from the command. As described above, the present invention can be applied to a wide range of machines ranging from simple toys (toys without a control device) to large-scale robots.

It is explanatory drawing of a four-bar linkage mechanism. It is explanatory drawing of Chebyshev's 1st approximate linear motion mechanism in a four-bar linkage mechanism. It is explanatory drawing of the assembly model and link mechanism of the quadruped running machine of this invention. It is explanatory drawing (side view) of the four-leg traveling machine of this invention. It is explanatory drawing of the 4-joint link mechanism in the leg part of the four-leg traveling machine of this invention. It is a figure for demonstrating the basic way of walking of a quadruped walking animal. It is a figure for demonstrating operation | movement of the front leg and the rear leg in the Example of the quadruped running machine of this invention. It is a figure for demonstrating operation | movement of the front leg and the rear leg in the Example of the quadruped running machine of this invention. It is a figure explaining the drive by the actuator in the Example of the quadruped running machine of this invention. It is a figure explaining the drive by the actuator in the Example of the quadruped running machine of this invention. It is explanatory drawing of the flexible beam in the Example of the quadruped running machine of this invention. It is explanatory drawing of the flexible beam in the Example of the quadruped running machine of this invention. It is a figure explaining the phase difference of the leg on either side in the Example of the quadruped running machine of this invention.

Explanation of symbols

1 Four-leg running machine 110 Front leg upper thigh 111 Front leg lower thigh 112 Rear leg upper thigh 113 Rear leg lower thigh 114 Foot (grounding part)
114f front leg foot portion 114b rear leg foot portion 120 flexible beam 121 pedestal 121f, b, l, r front, rear, left, right portion 130 in drive base 140 drive unit 140 power supply and control unit storage unit 150 front (head, For balance)

Claims (2)

In various gait quadruped running machines, each leg of the machine has a structure in which an upper part of a thigh provided with a four-joint link mechanism and a lower part of a thigh provided with a four-joint link mechanism are connected by a joint part. A four-leg traveling machine, characterized in that a pedestal for attaching the base and a pedestal for attaching the rear leg are connected by a flexible member having elasticity. The four-leg running machine according to claim 1, further comprising a mechanism for adjusting a phase of rotation of each leg by changing an attachment angle of a leg link of the four-bar linkage structure. Machine.