WO2009128125A1

WO2009128125A1 - Leg mechanism of multiple leg walking transfer equipment

Info

Publication number: WO2009128125A1
Application number: PCT/JP2008/057247
Authority: WO
Inventors: 克弥金岡
Original assignee: 学校法人立命館
Priority date: 2008-04-14
Filing date: 2008-04-14
Publication date: 2009-10-22
Also published as: JPWO2009128125A1; JP5268119B2

Abstract

A leg mechanism of multiple leg walking transfer equipment which can fulfill a torque generating function and a frictional force generating function even on irregular terrain and can obtain information on the shape of a supporting polygon and on a positional relationship with respect to the leg mechanism and which is simple, inexpensive, and break-proof. The leg mechanism (1) comprises a base member (2) attached to the lower end of a leg unit, three ground contact pieces (3), each having a ground contact face (3a), which are not arranged on a straight line, and swing mechanisms (4) which are set up for the respective ground contact pieces (3) to connect the corresponding ground contact pieces (3) to the base member (2) in a free swingable manner. Each of the swing mechanisms (4) connects the corresponding ground contact piece (3) to the base member (2) in such a manner that the ground contact piece (3) can passively swing around the swinging center located near the ground contact face (3a) when the ground contact piece (3) receives reaction force from the floor via the ground contact face (3a). The base member (2) is so structured as to be regarded as rigid in other directions than a normal direction to a plane including the swinging center of each ground contact piece (3).

Description

Foot mechanism of multi-legged walking device

The present invention relates to a foot mechanism which is attached to a leg unit of a multi-leg walking type moving apparatus and grounded.

A conventional multi-legged walking type mobile device, for example, a biped walking type robot, generally has an upper body unit 110 and

leg units

13 and 13 attached to the lower part of the upper body unit 110 as shown in FIG. Yes. The leg unit 13 includes a hip joint part 5, a knee joint part 7 connected to the hip joint part 5 via a thigh link 6, an ankle joint part 9 connected to the knee joint part 7 via a lower leg link 8, and an ankle The foot part mechanism 101 is connected to the joint part 9.

The hip joint portion 5 includes a swing shaft 51 around the Z axis, a swing shaft 52 around the X axis, and a swing shaft 53 around the Y axis. The knee joint portion 7 includes a swing shaft 71 around the Y axis. The ankle joint portion 9 includes a swing shaft 91 around the X axis and a swing shaft 92 around the Y axis. That is, the leg unit 13 has 6 degrees of freedom.
Here, the X-axis direction, the Y-axis direction, and the Z-axis direction refer to the front-rear direction (forward +), the lateral direction (right side +), and the vertical direction (upward +) of the biped walking robot 112. (same as below).

Each of the swing shafts 51 to 53, 71, 91, 92 is constituted by a drive motor that rotates around the respective shaft. Each drive motor is driven and controlled by a control unit 111 stored in the upper body unit 110.

The control unit 111 drives a gait generator (not shown) that generates gait data in response to an externally requested operation, and the drive motors of the

joints

5, 7, and 9 based on the gait data. A walking control unit (not shown) for controlling.

The gait generator generates gait data including the target angles, target angular velocities, and the like of the drive motors in the

joints

5, 7, and 9. The walking control unit swings the leg unit 13 in a predetermined walking pattern by driving and controlling the drive motors of the

joints

5, 7, and 9 according to the gait data. Thereby, the bipedal walking robot 112 realizes bipedal walking.

The ZMP norm can be applied to maintain the standing balance of the biped robot as described above. Here, “ZMP (Zero Moment Point)” is the pressure center of the floor reaction force received by the bottom of the robot, and when the sole is flat, the moment that the sole receives from the floor (the horizontal component of ) Is zero. The ZMP norm is a norm that the robot can walk stably without falling if the ZMP is inside a support polygon formed by connecting three or more grounding points with lines.

Based on this ZMP norm, by controlling the state of the robot so that an actual ZMP during walking (hereinafter referred to as an actual ZMP) matches a target ZMP in a predetermined walking pattern, Standing balance can be maintained.

By the way, the foot mechanisms of conventional multi-legged walking robots often have a single flat bottom. If the sole is a single plane, as shown in FIG. 15 (quoting FIG. 2 of Non-Patent Document 2), the entire sole may not touch the ground, such as riding on the convex portion P when walking on rough terrain. In this case, the area of the support polygon SP is small, and it is difficult to maintain a standing balance.

In general, the following two dynamic functions are expected from the bottom of the robot by ensuring a good contact and fixation with the ground.
A) Allowing the leg actuator to generate torque around the grounding point (torque generation function)
B) To be able to generate the friction force with the floor that is required as a reaction to the propulsive force of walking (friction force generation function)
The torque generation function is indispensable for realizing the standing balance maintenance of the biped walking robot, and the frictional force generation function is indispensable for the robot to obtain a propulsive force without sliding on the floor surface.

Furthermore, in the case where the standing balance of the robot is maintained by automatic control, it is desirable that the following two pieces of information can be acquired.
C) The shape of the support polygon SP and the positional relationship with the foot mechanism d) The position of the ZMP in the support polygon SP

However, in the situation as shown in FIG. 15 where walking is performed on a rough terrain with a sole composed of a single plane as described above, the mechanical functions of a) and b) are not realized. D) It is also difficult to obtain information. As described above, since the four requirements are not satisfied, it is difficult for the robot to walk and maintain a standing balance in the situation shown in FIG.

For this problem, for example, Non-Patent Document 1 points out the advantage of using a three-point support structure for the sole instead of a single plane. That is, by providing a three-point support structure for the sole, the ground contact property is improved even on rough terrain, and the torque generation function (a) is satisfied. Furthermore, a triangle having three contact points as vertices can always be used as the support polygon SP without depending on the shape of the rough terrain, and the acquisition of the information of c) is facilitated.

From the advantage of such a three-point support structure, a foot mechanism described in Patent Document 1 has been proposed.
As shown in FIG. 17 (cited FIG. 2 of Patent Document 1), the foot mechanism 301 described in Patent Document 1 mainly includes a base portion 302, and a flange portion 331 fixedly disposed near the rear end of the base portion 302. The joint portions (drive motors) 332 and 332 provided at the lower end of the base portion 302 extend substantially side by side from the

joint portions

332 and 332 and can swing up and down with respect to the base portion 302. And a pair of

foot tip portions

333 and 333 arranged. A triaxial force sensor 334 for obtaining floor reaction force information is provided on the lower surfaces of the distal ends of the heel portion 331 and the

toe portions

333 and 333. The

joint portions

332 and 332 are appropriately driven and controlled based on the detection values from the respective triaxial force sensors 334 so that the heel portion 331 and the

toe portions

333 and 333 are always grounded at three points even on rough terrain. It has become.

Further, a foot mechanism described in Non-Patent Document 2 has been proposed as a similar mechanism that is a four-point support structure instead of three points.
The foot mechanism 201 described in Non-Patent Document 2 has support members 203 that passively move up and down at the four corners of the foot mechanism 201 as shown in FIG. 16 (quoting FIG. 3 of Non-Patent Document 2). Therefore, it follows the unevenness of the road surface. Each support member 203 is provided with a switch (not shown) that senses grounding. When the switch senses the grounding of all four support members 203, each support member 203 is locked. As a result, the support polygon is quickly formed and held.

However, since the foot mechanisms of Patent Document 1 and Non-Patent Document 2 can be grounded only at points, the function of generating a frictional force (b) is not necessarily realized sufficiently. Furthermore, a force sensor having more axes than necessary to obtain the information (d) was required, and the mechanism was complicated, expensive and fragile.

Therefore, the present inventor employs a three-point support structure and includes three uniaxial force sensors that detect a force only in the normal direction of the virtual sole plane defined as a plane passing through all three grounding points. Thus, a foot mechanism has been proposed that can obtain the information of d) with a force sensor having a minimum number of axes (see Patent Document 2). As a result, a simple, inexpensive and hard-to-break mechanism is realized, but it is still point grounding, and the function of generating a frictional force in the a) is not sufficient.

Non-patent document 3 can be cited as an approach other than the three-point support structure. Here, there has been proposed a foot mechanism that secures high grounding property by using a remote center mechanism and a connecting differential mechanism in combination, and satisfies the functions of a) and b). However, the foot mechanism is a mechanism in which one remote center mechanism and a coupled differential mechanism having a large number of independent ground planes in one foot follow each other while deforming adaptively to uneven terrain. Since the center mechanism and the coupled differential mechanism do not have a fixing function in themselves, in order to satisfy the functions of a) and b) above, a free joint is used when adaptively following rough terrain, and a fixed structure is used after grounding. A brake mechanism that becomes a joint must be provided in the movable part of the remote center mechanism and the connecting differential mechanism.
In addition, in order to obtain the information of c), a large number of displacement sensors are arranged in a large number of movable parts of the remote center mechanism and the connecting differential mechanism, and the current posture of all the movable parts of the foot mechanism is measured. There must be. Furthermore, in order to acquire the information of (d), a force sensor with more axes than necessary is required, as in the case of a robot having a foot mechanism constituted by a single plane.
As described above, the foot mechanism of Non-Patent Document 3 can satisfy all of the conditions a), b), c), and d) by carefully designing the mechanism and sensor. It must be a complex structure.
JP 2004-90194 A Japanese Patent Application No. 2007-288103 Michihiko Shoji, Higashi Shishi, Takayuki Takahashi, Eiji Nakano: Foot structure for improving the standing ability of biped robots, Journal of Biomechanism Society, Vol.25, No.1, pp.36-42, 2001. Kenji Hashimoto, Yusuke Sugawara, Akihiro Hayashi, Masami Kawase, Akihiro Ota, Tomoaki Tanaka, Nobutsuka Endo, Nobumasa Sawado, Noritama Hayashi, Ikuo Takanishi: Development of a foot mechanism designed to improve the illegal land adaptability of biped robots (3rd report: Realization of rough terrain walking by developing a new holding mechanism), Proc. Of the 24th Annual Conference of the Robotics Society of Japan, 2F15, 2006. Masaru Ogata, Shigeo Hirose: Research on ankle mechanism of walking robot (basic consideration on function and form), Proc. Of 9th Robotics Symposia, pp. 1-7, 1A1, 2004.

The present invention has been made in view of the above circumstances. The object of the present invention is to be able to satisfy the conditions a), b) and c) on rough terrain at the same time, and to be simple, inexpensive and difficult to break. An object of the present invention is to provide a foot mechanism of a multi-leg walking type moving device.

In order to solve the above-described problems, the present invention provides (1) a foot mechanism that is attached to the lower end of a leg unit in a multi-leg walking type moving device and is grounded, and a base member that is attached to the lower end of the leg unit; There are three grounding pieces each having a grounding surface, each of which is not arranged in a straight line, and a swinging mechanism provided for each grounding piece and movably connected to the base member. And when the grounding piece receives a floor reaction force via the grounding surface, the grounding piece is connected so as to be able to passively swing around the swing center located near the grounding surface. And the base member is configured to be regarded as rigid with respect to a direction other than the normal direction of the plane including each of the swing centers. Is to provide.
Here, “foot” refers to a portion corresponding to an ankle to toe in humans, and “leg” refers to a portion corresponding to an ankle to pelvis in humans (hereinafter the same).

Further, the present invention is the above configuration, wherein (2) the swing mechanism is composed of three rigid rods each provided with a rotatable joint at each end, and each rod has one end connected to the rotatable joint. A triangular pyramid ridge line that is attached to the upper surface of the grounding piece and the other end is attached to the lower surface of the base member via the rotatable joint, and has the rocking center as a vertex in a reference posture. It is arrange | positioned so that it may comprise. The foot part mechanism of the multileg walking type moving apparatus characterized by the above-mentioned is provided.
Here, the “rotary joint” refers to a mechanical element that can rotate about three axes or two axes, such as a universal joint or a ball joint (hereinafter the same).

According to the present invention, in the configuration (1), (3) the swing mechanism includes three rigid rods each having an elastic member attached to both ends, and one end of each rod is interposed through the elastic member. Are attached to the upper surface of the grounding piece and the other end is attached to the lower surface of the base member via the elastic member to form a ridge line of a triangular pyramid having the rocking center as a vertex in a reference posture. The foot part mechanism of the multi-leg walking type moving device is provided.

According to the present invention, in the configuration (1), (4) the swing mechanism is composed of one rigid rod provided with a rotatable joint at one end, and the rod has one end of the grounding piece. Provided is a foot mechanism of a multi-legged walking type movement device, which is attached to the upper surface via the rotatable joint and the other end is fixed to the lower surface of the base member.

In addition, the present invention provides, in any one of the above-described configurations, (5) a translation / swivel mechanism that is provided for each grounding piece and that couples the swing mechanism to the base member so as to translate and / or pivot. When the grounding piece receives a floor reaction force through the grounding surface, the grounding piece is connected so as to be able to passively translate and / or swivel along a plane including the swing centers. The foot part mechanism of the multi-leg walking type moving device is further provided.

In addition, in any one of the above-described configurations, the present invention further includes (6) a biasing unit that biases the grounding piece in a direction to return to the predetermined posture when the grounding piece swings and / or translates from the predetermined posture. The foot part mechanism of the multi-leg walking type moving device is provided.

According to the present invention, in the configuration (1), (7) the swing mechanism is composed of three laminated rubbers in which a plurality of rubber plates and metal plates are alternately laminated, and each laminated rubber has one end Is attached to the upper surface of the grounding piece, and the other end is attached to the lower surface of the base member, and is arranged so as to constitute a triangular pyramid ridge line having the rocking center as a vertex in a reference posture. The foot part mechanism of the multi-leg walking type moving device is provided.

The foot mechanism of the present invention has a structure in which the soles are grounded at the grounding surfaces of the three grounding pieces that are dispersedly arranged so that the soles are not arranged in a straight line. Furthermore, each grounding piece can passively swing around the center of swinging located near the grounding surface in response to the floor reaction force, and can naturally follow the floor surface.

At this time, all of the three swing centers corresponding to the three grounding pieces can be regarded as grounding points fixed to the base member. That is, the foot mechanism of the present invention is substantially equivalent to the foot mechanism having the three-point support structure. Accordingly, the ground contact property is improved even on rough terrain, and the torque generation function of a) is satisfied. Furthermore, a triangle that has three swing centers fixed to the base member as vertices is always used as a support polygon without depending on the shape of the rough terrain and the swinging state of the grounding piece. This makes it easy to obtain the information of c).
This is an advantage not found in the foot mechanism of Non-Patent Document 3. In the foot mechanism of Non-Patent Document 3, a brake mechanism is required to satisfy the torque generation function of a), and a large number of displacement sensors are required to acquire the information of c). According to the above, the above a) and c) are realized without any necessity.

In addition, according to the foot mechanism of the present invention, even if there are undulations or protrusions on the floor surface, the three grounding surfaces are independently in contact with the floor surface in the vicinity of each swing center. Can be imitated. In other words, the foot mechanism of the present invention is substantially equivalent to the three-point support structure, but is grounded to the floor surface by three-surface contact instead of three-point contact. As a result, according to the present invention, there is provided a foot mechanism of a multi-legged walking type moving device that satisfies the functions (a) and (c) and the frictional force generation function of (a) and is simple, inexpensive, and difficult to break. The

According to the foot mechanism of the present invention, the swinging center of the grounding piece is positioned in the vicinity of the grounding surface, so that the standing leg (the foot is grounded) from the free leg (the foot is not grounded). It is possible to make a passive transition without turning the swinging mechanism and without causing a slip with the floor surface at the already grounded point.

Further, the foot mechanism of the present invention can be adapted to the foot mechanism of Patent Document 2. That is, the “grounding point” in the foot mechanism of the three-point support structure of Patent Document 2 is made to coincide with the “swing center” in the foot mechanism of the present invention, and the “virtual sole plane” of Patent Document 2 is It can coincide with the “plane including all three swing centers” in the foot mechanism of the invention.
As a result, as described above, the effect of obtaining the information (d) by the force sensor having the minimum number of axes, which is an advantage of the foot mechanism of Patent Document 2, can be introduced. Further, only the foot mechanism of Patent Document 2 can be introduced. The function of generating a frictional force (b), which could not be realized sufficiently, can be realized as an advantage of the foot mechanism of the present invention.
That is, when the foot mechanism of the present invention is adapted to the foot mechanism of Patent Document 2, it can satisfy all of the above a), a), c), and d) even on rough terrain, Necessary and sufficient information for maintaining the balance of position by automatic control can be acquired with a minimum number of sensors.

Further, according to the foot mechanism according to the configuration (6), the swinging mechanism and the translation / turning mechanism can be naturally returned to the equilibrium state at the time of transition from the standing leg to the free leg.

It is a perspective view which shows an example of the foot | leg part mechanism concerning this invention. It is a two-dimensional conceptual diagram for demonstrating the operating principle of the principal part of the foot | leg part mechanism of FIG. It is the schematic which shows an example of the bipedal walking robot to which the foot | leg part mechanism of FIG. 1 is applied. It is a block diagram which shows the structure of the control unit in the bipedal walking robot of FIG. It is a two-dimensional conceptual diagram for demonstrating the earthing | grounding aspect of the foot | leg part mechanism of FIG. It is a schematic diagram for demonstrating the copying operation | movement of the foot | leg part mechanism of FIG. It is a mimetic diagram for explaining copying operation of a foot mechanism of composition different from the present invention. It is a mimetic diagram for explaining copying operation of a foot mechanism of composition different from the present invention. It is a bottom view which shows the modification of the grounding piece in a foot | leg part mechanism. It is a perspective view which shows the modification of the base member in a foot | leg part mechanism. It is a side view which shows the modification of the rocking | fluctuation mechanism in a foot | leg part mechanism. It is a two-dimensional conceptual diagram for demonstrating another modification of the rocking | fluctuation mechanism in a foot | leg part mechanism. It is a two-dimensional conceptual diagram for explaining another modification of the swing mechanism in the foot mechanism. It is a two-dimensional conceptual diagram for demonstrating another modification of the base member in a foot | leg part mechanism. It is a two-dimensional conceptual diagram for demonstrating another modification of the base member in a foot | leg part mechanism. It is a two-dimensional conceptual diagram for explaining another modification of the swing mechanism in the foot mechanism. It is the schematic which shows an example of the biped walking type robot concerning a prior art example. It is a figure which shows the state at the time of the foot mechanism concerning a prior art example walking on rough terrain. It is a figure for demonstrating the foot part mechanism concerning another prior art example. It is a figure for demonstrating the foot part mechanism concerning another prior art example.

Explanation of symbols

C Oscillation center R Floor reaction force 1 Foot mechanism 2 Base member 3 Grounding piece 3a Grounding surface 4 Oscillation mechanism 13 Leg unit 26 Detector (Floor reaction force detector)

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the foot mechanism 1 according to the present embodiment includes a base member 2 attached to a lower end of a leg unit 13, which will be described later, and

grounding pieces

3, 3, 3 each having a flat grounding surface 3a. And a rocking mechanism 4 that is provided for each grounding piece 3 and that pivotably connects the grounding piece 3 to the base member 2.

The base member 2 includes a columnar main body 21 connected to the lower end of the leg unit 13,

intermediate portions

22, 22, 22 extending from the main body 21, and a columnar tip provided at the tip of each intermediate portion 22. And a compression spring 25 that urges the slide piece 24 in the sliding direction and against the floor reaction force.

Each intermediate part 22 is formed in a rod shape and extends from the main body part 21 downward in different directions.

As shown in FIG. 2, the distal end portion 23 has an accommodation hole 23 a for accommodating the shaft portion 24 a of the slide piece 24. A detector 26 for detecting the slide amount of the slide piece is disposed in the accommodation hole 23a. The detector 26 is a potentiometer, a laser displacement meter, a gap sensor, or the like. In addition, the said structure in the front-end | tip part 23 is compatible with the foot | foot part mechanism as described in patent document 2. FIG.

The slide piece 24 includes a shaft portion 24a and a plate portion 24b provided so as to be orthogonal to the tip of the shaft portion 24a. The shaft portion 24 a is accommodated and guided in the accommodation hole 23 a of the distal end portion 23. The slide direction of each slide piece 24 coincides with the normal direction of a plane including all the swing centers C described later.

The compression spring 25 is disposed between the lower surface of the tip portion 23 and the upper surface of the plate portion 24 b of the slide piece 24.

Based on the slide amount of the slide piece 24 detected by the detector 26, that is, the contraction amount of the compression spring 25 and the Hooke's law, it acts in the slide direction, that is, the normal direction of the plane including all the swing centers C described later. Only the floor reaction force is calculated.

The swing mechanism 4 is composed of three rigid rods 42 each having a ball joint portion 41a at one end and a ball joint portion 41b at the other end.

Each rod 42 is attached to the lower surface 24c of the plate portion 24b of the slide piece 24 via the ball joint portion 41a. At the same time, each rod 42 is attached to the upper surface 3b of the grounding piece 3 via the ball joint portion 41b. Here, there are three places where the ball joint portion 41a is attached to the slide piece 24 which are not aligned on a straight line. Similarly, there are also three places where the ball joint portion 41b is attached to the grounding piece 3 that are not aligned in a straight line. Each rod 42 forms a ridge line of a triangular pyramid that is sharpened toward the grounding piece 3 side. As shown in FIG. 2A, each rod 42 has the triangular pyramid apex T in the vicinity of the grounding surface 3a of the grounding piece 3 when the upper surface 3b of the grounding piece 3 and the lower surface 24c of the slide piece 24 are parallel to each other. It is arranged to be located.

When the grounding piece 3 connected to the base member 2 by the rocking mechanism 4 receives the floor reaction force R through the grounding surface 3a, as shown in FIG. 2B, the grounding piece 3 moves around the rocking center C located in the vicinity of the grounding surface 3a. Swing passively.

As shown in FIG. 3, the foot mechanism 1 configured as described above is a bipedal walking robot 12 having an upper body unit 10 and

leg units

13, 13. The main body 21 is connected and attached.

The leg unit 13 of the biped walking robot 12 includes a hip joint part 5, a knee joint part 7, an ankle joint part 9, a thigh link 6 connecting the hip joint part 5 and the knee joint part 7, and the knee joint part 7 and the ankle joint. The lower leg link 8 is connected to the portion 9.

The hip joint portion 5 includes a swing shaft 51 around the Z axis, a swing shaft 52 around the X axis, and a swing shaft 53 around the Y axis. The knee joint portion 7 includes a swing shaft 71 around the Y axis. The ankle joint portion 9 includes a swing shaft 91 around the X axis and a swing shaft 92 around the Y axis. Thereby, the leg unit 13 has 6 degrees of freedom.

Each of the swing shafts 51 to 53, 71, 91, 92 is constituted by a drive motor that rotates around the respective shaft. Each drive motor includes a rotary encoder that detects the amount of rotation. Each drive motor is driven and controlled by a control unit 11 stored in the upper body unit 10.

As shown in FIG. 4, the control unit 11 includes a gait generator 11a, a calculator 11b, a corrector 11c, and a drive motor controller 11d.

The gait generator 11a includes target angles, target angular velocities, target ZMPs, and the like of the swing shafts 51 to 53, 71, 91, and 92 in the leg unit 13 in response to a request operation signal input from the outside. Gait data is generated and output to the correction unit 11c.

The calculation unit 11b receives an angle signal of each drive motor from a rotary encoder provided in the drive motor of each

joint portion

5, 7, 9 in the leg unit 13. Based on the angle signal, the calculation unit 11b calculates joint state data related to the angles, angular velocities, etc. of the drive motors of the

joints

5, 7, 9 and outputs them to the drive motor control unit 11d.

Further, the floor reaction force detection value is input from the floor reaction force detector 26 in the foot mechanism 1 to the calculation unit 11b. The calculation unit 11b calculates an actual ZMP based on the floor reaction force detection value from each floor reaction force detector 26 and outputs it to the correction unit 11c.

The correction unit 11c includes the swing shafts 51 to 53 such that the actual ZMP input from the calculation unit 11b matches the target ZMP input from the gait generation unit 11a or is within the support polygon. , 71, 91, 92, gait data such as target angles and target speeds are corrected. The corrected gait data is input to the drive motor control unit 11d.

Based on the difference between the corrected gait data from the correction unit 11c and the joint state data from the calculation unit 11b, the drive motor control unit 11d generates control signals for the drive motors of the

joint units

5, 7, and 9. Generate. The drive motor control unit 11d controls the drive of each drive motor by outputting the control signal to each drive motor.

The foot mechanism 1 configured as described above is configured such that the soles are grounded by the grounding surfaces 3a of the three grounding pieces 3 that are dispersedly arranged so that the soles are not arranged in a straight line. Yes. Furthermore, each grounding piece can passively swing around the swinging center C located in the vicinity of the grounding surface in response to the floor reaction force, and can naturally follow the floor surface.

At this time, all the swing centers C corresponding to the respective grounding pieces 3 can be regarded as grounding points fixed to the base member 2. That is, the foot mechanism 1 of the present invention is substantially equivalent to the foot mechanism having the three-point support structure. Accordingly, the ground contact property is improved even on rough terrain, and the torque generation function (a) is satisfied. Further, it does not depend on the shape of the rough terrain and does not depend on the state of rocking of the grounding piece 3, and always supports a triangle having three rocking centers C fixed to the base member 2 as vertices. It is possible to obtain a square shape, and it becomes easy to acquire the information of c).

In addition, the foot mechanism 1 includes the detector 26 that is compatible with the foot mechanism described in Patent Document 2, so that only the floor reaction force acting in the normal direction of the plane including each swing center C is obtained. Each can be acquired. As a result, information on the actual ZMP based on the local coordinate axis fixed to the plane including each oscillation center C, that is, the information on the above (d) can be easily obtained.

Further, according to the foot mechanism 1, even if the floor has an undulation as shown in FIG. 5A and the floor has a protrusion P as shown in FIG. The floor surface can be imitated so as to be in contact with the floor surface in the vicinity of the moving center C. That is, the foot mechanism 1 is substantially equivalent to the three-point support structure, but is grounded to the floor surface by three-surface contact instead of three-point contact. As a result, according to the foot mechanism 1, the frictional force generation function of the above a) is satisfied simultaneously with the above a), c) and d).

Further, according to the foot mechanism 1, the swinging center C of the grounding piece 3 is positioned in the vicinity of the grounding surface 3a, so that when the transition is made from the free leg to the standing leg, as shown schematically in FIG. The amount of movement of the piece 3 in the direction along the floor surface is small, and it can follow the floor surface smoothly.
If the swing center C is far from the ground surface 3a, the amount of movement of the ground piece 103 in the direction along the floor surface increases as shown in FIG. become. Depending on the arrangement of the ground pieces 103, the ground pieces 103 interfere with each other as shown in FIG. 6B. Alternatively, as shown in FIG. 6C, there is a case where the swing mechanism is scratched and the copying operation cannot be performed.

Further, since the grounding piece 3 is passively oscillated, no driving means is required and the structure is simple.

Further, as described above, the foot mechanism 1 is configured to be compatible with the foot mechanism described in Patent Document 2. That is, the foot mechanism 1 matches the “grounding point” in the foot mechanism of the three-point support structure of Patent Document 2 with the “swing center C” in the foot mechanism of the present invention. The “plantar plane” is configured to coincide with the “plane including all three swing centers C” in the foot mechanism of the present invention.
As a result, the effect of obtaining the above information (d) by the force sensor having the minimum number of axes, which is an advantage of the foot mechanism of Patent Document 2, can be introduced. Further, only the foot mechanism of Patent Document 2 can be sufficiently realized. The frictional force generating function of a) that has not been achieved is realized.
That is, the foot mechanism 1 can satisfy all of the above a), b), c), and d) even on rough terrain, and to maintain the standing balance of the biped robot 12 by automatic control. The foot mechanism of the multi-legged walking type mobile device that can acquire necessary and sufficient information with only the minimum number of detectors 26 and is simple, inexpensive, and difficult to break.

Further, according to the foot mechanism 1, since the compression spring 25 relieves the impact when touching the ground, it is possible to protect each drive part and each joint part of the multi-leg walking type moving device.

[Modification]
Although the embodiments of the present invention have been specifically described above, the present invention can be implemented with the following modifications.

The area and shape of the three ground planes 3a can be appropriately selected as long as they do not interfere with each other at the time of swinging. As shown in FIG. 7A, the area of each ground plane 3a may be different. As shown in FIGS. 7B and 7C, the shape of each ground plane 3a may be different.

The shape of the base member 2 may be any shape as long as it does not contact the floor and does not interfere with the swing of the grounding piece 3.
Furthermore, the base member 2 may not include the slide piece 24 as shown in FIG. In this case, one end of the swing mechanism 4 is attached to the lower surface of the tip portion 23a of the base member 2a. In this case, a known floor reaction force detector 26 a such as a pressure sensor may be provided between each tip 23 a and the swing mechanism 4, for example.

For example, as shown in FIG. 9, the swing mechanism 4 has one end of one rigid rod 42 attached to the lower surface 24c of the slide piece 24 and the other end attached to the upper surface 3b of the ground piece 3 via a ball joint or universal joint 41c. The swing mechanism 4a attached to can also be used. In this case, it is necessary to arrange the ball joint or universal joint 41c so that the swing center C of the grounding piece 3 is located as close to the grounding surface 3a as possible.

For example, as shown in FIG. 10A, the swing mechanism 4 has one end of three rods 42 attached to the lower surface 24c of the slide piece 24 via an elastic member 41d such as a spring and the other end connected to an elastic member 41e such as a spring. The swinging mechanism 4b attached to the upper surface 3b of the grounding piece 3 may be used.
Further, as shown in FIG. 10B, a spring 43 can be provided between the

surfaces

24c and 3b to which the swing mechanism 4 is attached.
When the grounding piece 3 is released from the floor reaction force by the elastic member such as a spring, the grounding piece 3 is brought into a reference posture (in this case, the upper surface 3b of the grounding piece is parallel to the lower surface 24c of the slide piece 24). It can be restored naturally.

11, the base member 2 may be provided with a translation / turning mechanism 27 that can passively translate and / or turn the surface to which the swing mechanism 4 is attached along the surface. The translation / swivel mechanism 27 is, for example, a circular box 24d connected to the lower end of the shaft 24a of the slide piece 24 and having an opening 24e at the bottom, a translation plate 28 accommodated in the circular box 24d, The three rigid rods 29 attached to the lower surface 28a of the translation plate 28 and the bottom surface 24f of the circular box 24d via ball joints or

universal joints

29a and 29b, respectively. The grounding piece 3 is attached to the lower surface 28 a of the translation plate 28 via the swing mechanism 4.

In such a configuration, as shown in FIG. 11B, the translation plate 28 can passively translate and / or swivel along the lower surface 28a. Therefore, the grounding piece 3 attached to the translation plate 28 can likewise translate and / or pivot in a passive manner. As described above, the foot mechanism 1 has a small amount of movement in the direction along the floor surface of the grounding piece 3 and can smoothly follow the floor surface. However, by providing the translation / turning mechanism 27 further, This slight slip on the floor surface is also absorbed, and it is possible to imitate without slipping at all.

For example, as shown in FIG. 12, the translation / revolution mechanism 27 uses three rigid rods 29 attached to the lower surface 28a of the translation plate 28 and the bottom surface 24f of the circular box 24d via

springs

29c and 29d, respectively. The translation / swivel mechanism 27a may be configured.

Further, as shown in FIG. 13, the swing mechanism 4 is composed of three laminated rubbers 44 formed by alternately laminating a plurality of rubber plates and metal plates, one end of which is attached to the lower surface 24 c of the slide piece 24. Alternatively, the swing mechanism 4d may include a plate 45 to which the other end of the laminated rubber 44 is attached, and a spacer 46 disposed between the plate 45 and the grounding piece 3. Here, the laminated rubber 44 is arranged so as to form a triangular pyramid ridge line having the swing center C as a vertex T in a state where the upper surface 3b of the ground piece 3 and the lower surface 24c of the slide piece 24 are parallel to each other. Yes.

According to the swing mechanism 4d, the grounding piece 3 can swing around the swing center C as shown in FIG. 13B, and as shown in FIG. 13C, it translates in a plane parallel to the lower surface 24c of the slide piece 24. Can exercise.

Further, the three ground planes 3a may be sealed by being connected to each other with a flexible material such as a waterproof cloth or rubber in order to prevent dust and water. Further, not only the ground contact surface 3a but also the swing mechanism 4, the translation / swivel mechanism 27, and the base member may be sealed.

Claims

A foot mechanism that is attached to the lower end of a leg unit in a multi-legged walking device and is grounded,
A base member attached to the lower end of the leg unit;
Three grounding pieces each having a grounding surface, each not aligned in a straight line,
A rocking mechanism provided for each grounding piece and movably connecting the grounding piece to the base member when the grounding piece receives a floor reaction force via the grounding surface. Are connected so as to be capable of passively swinging around a swing center located in the vicinity of the ground plane,
The foot mechanism of the multi-legged walking type moving device, wherein the base member is configured to be considered to be rigid with respect to a direction other than a normal direction of a plane including the swing centers.
The swing mechanism is composed of three rigid rods provided with rotatable joints at both ends,
Each rod has one end attached to the upper surface of the grounding piece via the rotatable joint and the other end attached to the lower surface of the base member via the rotatable joint. 2. The foot mechanism of the multi-legged walking type moving device according to claim 1, wherein the foot mechanism is arranged so as to form a ridge line of a triangular pyramid having the swing center as a vertex.
The swing mechanism is composed of three rigid rods each having an elastic member attached to both ends. Each rod has one end attached to the upper surface of the grounding piece via the elastic member and the other end. 2. The ridge line of the triangular pyramid, which is attached to the lower surface of the base member via the elastic member and has a vertex at the swing center in a reference posture. The foot mechanism of the described multi-legged walking type moving device.
The swing mechanism is composed of one rigid rod provided with a rotatable joint at one end,
2. The rod according to claim 1, wherein the one end of the rod is attached to the upper surface of the grounding piece via the rotatable joint portion, and the other end is fixed to the lower surface of the base member. Foot mechanism of a multi-legged walking device.
A translation / swivel mechanism provided for each grounding piece to connect the swing mechanism to the base member so as to be able to translate and / or pivot. The grounding piece receives a floor reaction force via the grounding surface. In this case, the grounding piece further includes a connecting member that can passively translate and / or pivot along a plane including the swing centers. The foot part mechanism of the multileg walking type moving apparatus of any one of these.
The urging means for urging the grounding piece in a direction to return to the predetermined posture when the grounding piece swings and / or translates from the predetermined posture. A foot mechanism of the multi-legged walking type moving device according to claim 1.
The swing mechanism is composed of three laminated rubbers formed by alternately laminating a plurality of rubber plates and metal plates,
Each of the laminated rubbers has one end attached to the upper surface of the grounding piece and the other end attached to the lower surface of the base member to form a triangular pyramid ridge line having the swing center as a vertex in a reference posture The foot part mechanism of the multi-leg walking type moving apparatus according to claim 1, wherein the foot part mechanism is arranged so as to do so.