JP2005040919A - Motion base - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motion base which affects kinesthetic sense of a leg type moving robot in a wide movable scope. <P>SOLUTION: This motion base is composed of a base, a table, and a plurality of arms connecting them. The arm is a serial arm having a two link configuration. A lower part link is connected with the base through an actuator having a predetermined rotary shaft at its lower end and a passive joint crossing the actuator orthogonally and having degree of freedom in rotation. An upper end of the lower part link is connected with an upper part link through the actuator, and an upper end of the upper part link is connected with the table through a passive joint having three degrees of freedom. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motion base that operates in each direction of surge (front and rear) and heave (up and down), roll, and pitch, and affects the kinesthetic sense of the mounted object, in particular, the mounted leg type The present invention relates to a motion base that allows a mobile robot to have a simulated experience of receiving disturbance in an upright state or walking state.

  More specifically, the present invention relates to a motion base in which a pedestal and an upper structure are connected by a plurality of legs, and the upper structure is displaced in each direction by the operation of each leg. It is related to the motion base that affects the sense of movement to the legged mobile robot.

  A mechanical device that uses an electrical or magnetic action to perform a movement resembling human movement is called a “robot”. It is said that the word “robot” comes from the Slavic word “ROBOTA (slave machine)”.

  In Japan, robots started to spread from the end of the 1960s, but many of them are industrial robots such as manipulators and transfer robots for the purpose of automating and unmanned production operations in factories. Met. Recently, research and development on legged mobile robots has progressed, and expectations for practical use have also increased. A legged mobile robot modeled on human movement is particularly called a “humanoid” or “humanoid robot”.

  Leg type movement with two legs standing up is unstable and difficult to control posture and walking, compared to crawler type, four or six legs type, etc., but walking with irregularities on the work path such as rough terrain and obstacles It is excellent in that it can realize flexible movement work, such as being able to cope with discontinuous walking surfaces such as up and down of surfaces and stairs and ladders.

  Many techniques relating to posture control and stable walking related to a biped legged mobile robot have already been proposed. Stable “walking” as used herein is defined as “moving with legs without falling down”. The overturning of the airframe means that the robot is interrupting the work being executed, and considerable effort and time are spent to get up from the overturned state and resume the work. In addition, there is a risk that the robot body itself or the object on the other side colliding with the falling robot may be fatally damaged by the fall. For this reason, posture stability control for avoiding falls is positioned as one of the most important issues in the development of legged mobile robots.

  In a robot that performs upright walking, the normal upright posture as a basic posture is unstable in the first place. In many cases, ZMP (Zero Moment Point) is used as a norm for determining the stability of walking for posture stability control of a legged mobile robot. The standard for discriminating the stability by ZMP is the principle of d'Alembert that gravity and inertia force from the walking system to the road surface, and these moments balance with the floor reaction force and the floor reaction force moment as reaction from the road surface to the walking system. based on. As a result of dynamic reasoning, there is a point where the pitch axis and roll axis moments become zero, that is, ZMP, on or inside the side of the support polygon (that is, the ZMP stable region) formed by the sole contact point and the road surface (ie, ZMP) ( For example, see Non-Patent Document 1.)

  On the other hand, in the course of developing legged mobile robots, it is necessary to perform simulations to determine whether the aircraft can maintain posture stability even when it receives unexpected disturbances during walking or other legged work. In this simulation, it is necessary for the robot to perform a simulation experience by applying an actual disturbance such as a fluctuation of the floor surface in addition to the calculation.

  Motion base is known as a device for performing the latter simulated experience. A typical motion base is called the Stuart Platform type. The Stuart platform consists of a pedestal and an upper structure connected by a plurality of legs. The upper structure has six degrees of freedom with respect to the pedestal, that is, the floor, and includes surge (front and rear) and heave (up and down). ), Acting in each direction of roll and pitch, can affect the kinesthetic sense of the mounted object (see, for example, Patent Document 1 and Patent Document 2).

  A large motion base is a vehicle simulator (such as a flight or driving simulator), and a small one is for dynamic inspection of optical equipment. Large payloads are on the order of several hundred kgf to several t, and small payloads are on the order of several hundred gf.

  In the conventional motion base, the legs connecting the base and the table are composed of multiple (6 sets are standard) linear motion actuators (such as a combination of a ball screw and a motor), and the position and orientation of the table are driven by the actuator. Is to control. These mechanisms are called “parallel link mechanisms” because the outputs of the actuators are combined to produce an output on the table side.

  FIG. 7 illustrates a configuration example (conventional example) of the motion base. In the example shown in the figure, the leg can be configured by using an extendable linear actuator, and the posture can be determined by adjusting the distance between each joint of the base and the table.

  FIG. 8 illustrates another configuration example (conventional example) of the motion base. In the example shown in the figure, the table posture can be changed by moving the arm lower part (base side) up and down.

  In both the examples shown in FIGS. 7 and 8, the position and orientation of the table are determined by determining the positions in space of the three portions of the table. The following features can be cited for this Stuart platform:

(1) The gear ratio in the Z-axis direction (vertical direction) is low and suitable for supporting an object.
(2) The mechanism has high rigidity and excellent positioning accuracy.

  Instead, there are the following problems.

(1) Due to the denseness of the mechanism elements, the movable range is limited.
(2) It is difficult to obtain a speed in the Z-axis direction.

  Because of these features, the conventional Stuart platform type motion base is suitable for general purposes such as flight simulators and optical instrument calibration, and is generally used.

  However, there is currently no product of the order of several kgf to several tens of kgf. Further, since the parallel link mechanism is applied to the arm that realizes the displacement of the table with respect to the base, the movable range is restricted.

JP-A-9-217730 JP 2000-140444 A "Migir Vokobratovic" "LEGGED LOCATION ROBOTS" (Ichiro Kato's "Walking Robot and Artificial Feet" (Nikkan Kogyo Shimbun))

  An object of the present invention is to provide an excellent motion base in which a pedestal and an upper structure are connected by a plurality of legs, and the displacement of the upper structure can be suitably performed by the operation of each leg. There is to do.

  It is a further object of the present invention to provide an excellent motion base capable of suitably performing a simulated experience of receiving a disturbance in an upright state or a walking state with respect to a mounted legged mobile robot.

  It is a further object of the present invention to provide an excellent motion base that can affect the kinematics of a legged mobile robot with a wider range of motion.

The present invention has been made in consideration of the above problems, and is a motion base that affects the kinesthetic sense of a mobile robot,
Base and
A table carrying a mobile robot;
A plurality of arms connecting the base and the table;
Each of the arms has a two-link configuration including an upper link connected to the table and a lower link connected to the base.
At a substantially lower end of the lower link, a connecting portion between an actuator having an active degree of freedom with respect to the base and a base having a passive joint having a degree of freedom of rotation perpendicular to the rotation axis of the actuator;
An inter-link connecting portion made of an actuator that gives an active degree of freedom at a substantially upper end of the lower link and a substantially lower end of the upper link; With a connecting part with
It is a motion base characterized by this.

  The motion base according to the present invention takes the form of a parallel arm and is equipped with a total of 18 joints. Since the table needs to be supported at a minimum of three places, three sets of arms are used as described above. Moreover, the distance and direction can be determined by setting the arm to a two-link type. In order to arbitrarily determine the position and orientation of the table with respect to the base, six degrees of freedom are required with respect to the center of the base. In order to realize this degree of freedom with three pairs of arms, two active joints, that is, actuators may be arranged equally on each arm. On the other hand, in order to determine the position of the tip of each arm, three degrees of freedom are required, for a total of nine degrees of freedom. However, as described above, six active degrees of freedom are sufficient for controlling the position and posture of the table, so the remaining three degrees of freedom may be passive degrees of freedom. Therefore, the degree of freedom on the base side can be configured with a passive joint.

  Here, six degrees of freedom are required per arm. A passive rotary joint perpendicular to the arm drive actuator is arranged at the lower end of the lower link, and a passive rotary joint intersecting three orthogonal axes is arranged at the tip of the upper link. . In order to arbitrarily determine the position and position of the table, these passive rotary joints should theoretically be sufficient, but if the strength of the gimbal mechanism (joint) is ensured, the mechanism will easily interfere. Depending on the position of the table, it is not possible to obtain a movable angle. For this reason, a rotation support portion having a degree of freedom of rotation around the yaw axis (or around the longitudinal axis of the joint portion) is provided at each of the upper and lower ends of the joint portion. A wide movable range can be obtained by giving such an extra degree of freedom.

  According to the present invention, an excellent motion base is provided in which the base and the upper structure are connected by a plurality of legs, and the upper structure can be suitably displaced in each direction by the operation of each leg. can do.

  In addition, according to the present invention, it is possible to provide an excellent motion base that can favorably perform a simulated experience of receiving a disturbance in an upright state or a walking state with respect to a mounted legged mobile robot.

  Furthermore, according to the present invention, it is possible to provide an excellent motion base that can affect the motion sensation of a legged mobile robot in a wider range of motion.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

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

  The inventors propose a motion base comprising a hybrid mechanism of a serial link and a parallel link, after thoroughly examining the features of the conventional parallel link mechanism and the Stuart platform.

  FIG. 1 shows an external configuration of a motion base 10 according to an embodiment of the present invention.

  As shown in the figure, the motion base 10 is composed of a base 20 integrated with the floor surface, a table 30 and a plurality of arms 40 connecting them. Has freedom. In the example shown in the figure, two motors, that is, three arms having active joints are combined in parallel, and a table 30 is attached to the tip thereof to operate. That is, by placing the legged mobile robot on the table 30, it is possible to affect the kinesthetic sense in each direction of surge (front and back), heave (up and down), roll, and pitch.

  FIG. 2 schematically shows the mechanism configuration of the arm 40 that connects the base 20 and the table 30.

  The illustrated arm 40 is a serial arm having a two-link configuration including a lower link 41 and an upper link 46.

  The lower link 41 connected to the base 20 is connected to the base 20 via an actuator 42 as an active joint having a predetermined rotation axis at a lower end thereof, and a passive joint 45 having a degree of freedom of rotation orthogonal to the actuator 42. ing. The upper end of the lower link 41 is connected to the upper link 46 via an actuator 43 as an active joint. The upper end of the upper link 46 is connected to the table 30 through a passive joint (joint) 44 having three degrees of freedom. The configuration of the three-degree-of-freedom joint 44 will be described later.

  Now, in order to arbitrarily determine the position and orientation of the table 30 with respect to the base 20, six degrees of freedom are required with respect to the center of the base 20. In order to realize this degree of freedom with the three sets of arms 40, it is only necessary to arrange two active joints, that is, actuators, equally on each arm 40.

  That is, in the example shown in FIG. 2, when three serial arms 40 are combined, there are a total of 6 links and 6 joints, so all 6 degrees of freedom may be configured by active joints, that is, actuators 42 and 43. .

  On the other hand, in order to determine the tip position of each arm 40, three degrees of freedom are required, and a total of nine degrees of freedom is obtained. However, as described above, six active degrees of freedom are sufficient for the position and posture control of the table 30, so that the remaining three degrees of freedom may be passive degrees of freedom. Therefore, the degree of freedom on the base 20 side is configured by the passive joint 45.

  In this embodiment, since the form of a parallel arm is taken, it is necessary to equip a total of 18 joints. The table 30 needs to be supported in at least three places. For this reason, as described above, three sets of arms 40 are used. Moreover, the distance and direction can be determined by setting the arm 40 to a two-link type. Here, 6 degrees of freedom are required per arm. As shown in FIG. 2, a passive rotary joint 45 that is orthogonal to the arm drive actuator 42 is disposed on the lower link 41, and a passive rotary joint 44 that intersects three orthogonal axes is disposed on the tip of the upper link 45.

  In the present embodiment, a gimbal mechanism is introduced at a portion of the passive rotary joint 44 where the three orthogonal axes intersect. FIG. 3 schematically shows a mechanism configuration of the passive rotary joint 44 in which three orthogonal axes intersect. In the example shown in the figure, a rotation support portion that gives a degree of freedom of rotation about the yaw axis is connected to an upper end of the center of the gimbal mechanism that gives a degree of freedom of rotation about the roll axis and the pitch axis. However, the yaw axis here means the yaw axis in a state where the gimbal mechanism is extended. Therefore, when the joint portion is bent, the degree of freedom of rotation about the yaw axis corresponds to the degree of rotation with respect to the longitudinal direction of the joint.

  Theoretically, in order to arbitrarily determine the position and posture of the table 30, the arm 40 should be sufficient with the passive joints 44 and 45 in addition to the two actuators 42 and 43. However, if the strength of the gimbal mechanism (joint) is ensured, there is a problem that the mechanism is liable to interfere, and depending on the posture of the table 30, it is difficult to obtain a movable angle. By the way, a general universal joint has a large movable range of about ± 45 ° (± 90 ° if the direction is correct).

  FIG. 4 shows another configuration of the mechanism of the passive rotary joint 44 in which three orthogonal axes intersect. In the example shown in the figure, a rotation support portion that gives a degree of freedom of rotation about the yaw axis is connected to both the upper end and the lower end of the center of the gimbal mechanism that gives the degree of freedom of rotation about the roll axis and the pitch axis.

  By adding one extra degree of freedom in this way, even if the frames of the joint part (gimbals) that are the cores interfere with each other, the extra degree of freedom avoids this, so it is virtually nearly ± 90 °. The effective movable angle can be realized.

  According to the motion-based mechanism configuration method according to the present embodiment, the following features can be imparted to the conventional Stuart platform type.

(1) Realization of a lightweight system tailored to the purpose The feature of the conventional motion base is that it can withstand a very large load or can be used for precision instrument measurement utilizing high rigidity. There was nothing to endure use. That is, the scale of the device itself and the system (control / drive system) is large for the payload, and it cannot be used easily. On the other hand, in the motion base according to the present embodiment, the drive system and the mechanism system can be designed according to the scale of the test object, and the components can be reduced in weight.

(2) Driving force (no torque interference) and few failures As shown in Fig. 2, each arm has a two-link configuration in which active joints (actuators) are arranged only at the connection between links. It is possible to produce. In this case, however, the force (torque) generated by the motor may interfere with the orientation of the table. In such a mechanism control system, the interference of servo forces can lead to a decrease in energy efficiency and failure due to overload. On the other hand, in the motion base according to the present embodiment, the motor torque does not interfere, and the mechanism and control system (actuator, drive circuit, etc.) can be damaged even if there is an abnormality due to some servo error. It is thought that there are few.

(3) Dramatically expand the movable angle and expand the range of use As described above, in the present embodiment, the passive joint 44 connecting the tip of the arm 40 and the table 30 is not theoretically necessary. 3 degrees of freedom are provided. That is, the passive joint 44 is connected to both the upper end and the lower end of the center of the gimbal mechanism that gives the degree of freedom of rotation about the roll axis and the pitch axis, respectively, with rotation support portions that give the degree of freedom of rotation about the yaw axis. . (See FIG. 4). As a result, the motion base can take a free posture and can also translate, so that the joint mechanism of the passive joint 44 is largely twisted in the vicinity of the support joint of the table 30. . (However, the yaw axis here means the yaw axis when the gimbal mechanism is extended. Therefore, when the joint portion is bent, the degree of freedom of rotation around the yaw axis is the degree of freedom of rotation of the joint. (This corresponds to the degree of rotation in the longitudinal direction.)

  In the case of a general configuration as shown in FIG. 6, when the joint is inclined in an axial direction that forms 45 ° with respect to a plane including two joint axes, the components interfere with each other and a sufficient movable angle cannot be obtained. There is a case.

(4) Realization of Control System with Anisotropic Compliance The motion base according to the present embodiment has a wide range of selection of actuators used in the drive unit, and therefore has an advantage that compliance can be freely set. However, since the three arms 40 are parallel in the upward direction, the force in the Z-axis direction is easily generated. Since the rigidity is high in the Z-axis direction and a large force can be generated, it is considered that there is an excellent characteristic of a device for moving an experimental object such as a legged mobile robot on the table 30.

[Supplement]
The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the gist of the present invention.

  The gist of the present invention is not necessarily limited to a product called a “robot”. That is, if it is a mechanical device or other general mobile device that performs a movement resembling human movement using electrical or magnetic action, it is a product belonging to another industrial field such as a toy. Even if it exists, this invention can be applied similarly.

  In short, the present invention has been disclosed in the form of exemplification, and the description of the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims section described at the beginning should be considered.

It is the figure which showed the external appearance structure of the motion base 10 which concerns on one Embodiment of this invention. It is the figure which showed typically the mechanism structure of the arm 40 which connects the base 20 and the table 30. FIG. It is the figure which showed typically the structural example of the gimbal mechanism introduce | transduced into the passive rotary joint 44 which 3 orthogonal axes cross | intersect. It is the figure which showed typically the example of another structure of the gimbal mechanism introduce | transduced into the passive rotary joint 44 which 3 orthogonal axes cross | intersect. It is the figure which showed the external appearance of the motion base which consists of 2 link structure which has arrange | positioned the active joint (actuator) only to the connection part between each arm. It is a figure for demonstrating the movable range of a general joint mechanism. It is the figure which showed one structural example (conventional example) of the motion base. It is the figure which showed one structural example (conventional example) of the motion base.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Motion base 20 ... Base 30 ... Table 40 ... Arm 41 ... Lower link 42 ... Actuator 43 ... Actuator 44 ... Passive joint 45 ... Passive joint 46 ... Upper link

Claims (2)

A motion base that affects the kinesthetic sense of a mobile robot,
Base and
A table carrying a mobile robot;
A plurality of arms connecting the base and the table;
Each of the arms has a two-link configuration including an upper link connected to the table and a lower link connected to the base.
At a substantially lower end of the lower link, a connecting portion between an actuator having an active degree of freedom with respect to the base and a base having a passive joint having a degree of freedom of rotation orthogonal to the rotation axis of the actuator;
An inter-link connecting portion made of an actuator that gives an active degree of freedom at a substantially upper end of the lower link and a substantially lower end of the upper link; With a connecting part with
A motion base characterized by that. The passive joint at the connection with the table is:
A joint having a degree of freedom of rotation about the roll axis and the pitch axis;
A rotation support portion having a degree of freedom of rotation around the longitudinal axis of the joint portion, which is disposed at both upper and lower ends of the joint portion;
The motion base of claim 1, comprising:

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