CN114939877B - A portable operation spherical robot for moon base is built - Google Patents

A portable operation spherical robot for moon base is built Download PDF

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Publication number
CN114939877B
CN114939877B CN202210547443.7A CN202210547443A CN114939877B CN 114939877 B CN114939877 B CN 114939877B CN 202210547443 A CN202210547443 A CN 202210547443A CN 114939877 B CN114939877 B CN 114939877B
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spherical
arm
robot
smart
rigid
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CN114939877A (en
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孙汉旭
李明刚
王展彤
马龙
孙萍
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Beijing Normal University
Beijing University of Posts and Telecommunications
CCTEG China Coal Research Institute
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Beijing Normal University
Beijing University of Posts and Telecommunications
CCTEG China Coal Research Institute
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25JMANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J11/00Manipulators not otherwise provided for

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  • Engineering & Computer Science (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
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Abstract

The invention discloses a movable operation spherical robot for moon base construction. The invention provides a movable operation spherical robot comprising: the flexible cable driving expandable spherical shell (1), a rigid-flexible coupling super-redundant operating arm base (2), a flexible tail end buffer joint (3), a rigid-flexible coupling telescopic joint (4), an internal spherical antenna (5), an internal spherical solar sail (6), an automatic release and locking mechanism (7), a smart arm (8) and a smart arm tail end (9). The configuration change of the rigid-flexible coupling super-redundant operation arms is used as a centroid change mechanism of a spherical moving state, so that the spherical robot can flexibly and stably roll, after the spherical robot reaches a designated position, the double smart arms can assist the spherical shell to be completely opened, the two large super-redundant operation arms and the smart arms cooperatively operate and complete external operation, the robot has the characteristic of multiple arms in the ball capable of operating externally, the combined cooperation obstacle surmounting of the multiple robots can be realized under the moving state, and the environment adaptation and multi-machine cooperation are realized.

Description

A portable operation spherical robot for moon base is built
Technical Field
The invention relates to a movable operation spherical robot for moon base construction, in particular to a spherical robot with a super-redundant operation arm, which can realize the omnidirectional movement, spherical shell opening and closing, external operation and the like of the spherical robot through the action of an inner mechanical arm of a sphere, and can realize environment adaptation and multi-machine cooperation through the mutual communication with other robots, and belongs to the field of robots.
Background
The lunar surface transportation and operation facility is used as a core component of the international lunar surface scientific research station, provides object transportation and operation for a lunar surface long-term work support system and a lunar surface scientific research facility system, and provides mature conditions for the foreign star to and fro by the development and achievement of the aerospace technology in China, so that the research of building a robot by the foreign star base is focused and necessarily developed at home and abroad. The lunar environment is extremely harsh: rugged road surface, vacuum, large day and night temperature difference, moon dust pollution, long moon night, low gravity and the like, and provide great challenges for the design of robots. The spherical robot has the advantages of omnidirectional movement, sealing, anti-overturning and less driving, so that the spherical robot has rapid and flexible movement capability and self-protection capability in extreme environments. Aiming at the extreme environment of the lunar surface and the complex task constraint of the foundation construction, a pen user provides a movable operation spherical robot for the lunar foundation construction through the innovative fusion of the spherical robot and the mechanical arm, and provides technical reference for the lunar foundation construction in China.
The application number 202110540392.0 discloses a spherical robot, is provided with rolling drive arrangement and jump drive arrangement in this robot spherical shell, and rolling drive arrangement includes supporting mechanism, loading mechanism, servo motor group one and servo motor group two, and jump drive arrangement includes jump mechanism, locking mechanism and counter weight platform, provides a compact structure space utilization height's self-service spring spherical robot of saving oneself. The invention has good trafficability, but does not have external operation capability.
The application number 202110393069.5 discloses a spherical detection robot with an arm, the robot rolls under the action of steering engine driving force, a weight pendulum and the gravity of a mechanical arm, the spherical shell is adjusted to be unfolded or closed through a deformation assembly, and the external operation of the mechanical arm is realized under the condition that the spherical shell is unfolded. The mechanical arm additionally arranged in the ball body can only realize external operation when the ball shell is opened.
The application number 201621174315.9 discloses a spherical transfer robot, which is characterized in that two mechanical arms are arranged on two sides of the spherical robot in a non-opening and closing mode, so that objects can be clamped or placed, but the spherical transfer robot is limited by a sphere, the operable space is not large, the operability is not high, and the protection effect of a closed spherical shell on the mechanical arms in the moving process is abandoned.
The invention combines the design ideas of the spherical robot and the ultra-redundant large-scale space mechanical arm and provides a movable operation spherical robot for lunar base construction, which integrates the research ideas of the existing spherical robot and the large-scale space mechanical arm and the complex and extreme task demands on the surface of an extraterrestrial sphere: the spherical robot has the advantages that the robot arm has high and flexible movement capability and self-protection capability under extremely complex outer planet environments, meanwhile, the robot arm has strong external operation capability and cooperation capability among multiple robot units, so that the robot can realize efficient and reliable movement and external operation in a foundation construction task under the extreme environment of the lunar surface, and the robot has great potential advantages and profound research value.
Disclosure of Invention
The invention provides a movable operation spherical robot for moon base construction. The robot disclosed by the invention uses the configuration change of the rigid-flexible coupling super-redundant operation arm as a centroid change mechanism of a spherical moving state, so that the spherical robot can flexibly and stably roll; after reaching the appointed position, the double smart arms can assist the spherical shell to be completely opened; the two large super-redundant operation arms and the smart arm (8) cooperate to complete the construction operation. The robot has the characteristics of multiple arms in the ball which can be operated outwards, the combined cooperation obstacle surmounting of the multiple robots can be realized under the moving state, and meanwhile, the smart arm can extend out of the spherical shell to operate in motion. The cooperation of a plurality of super-redundant operation arms and smart arms can be realized under the external operation state, and the complex operation task is completed.
In order to achieve the above object, the present invention provides a solution that:
the spherical robot comprises a flexible rope driven expandable spherical shell (1), a rigid-flexible coupling super-redundant operating arm base (2), a soft tail end buffer joint (3), a rigid-flexible coupling telescopic joint (4), an intra-spherical antenna (5), an intra-spherical solar sail (6), an automatic release and locking mechanism (7), a smart arm (8) and a smart arm tail end (9).
The rigid-flexible coupling super-redundancy operating arm base (2) is connected with the flexible cable driven expandable spherical shell (1) through the automatic release and locking mechanism (7) in a spherical cruising mode, the spherical solar sail (6) is attached to the inner surface of the spherical shell, and the rigid-flexible coupling super-redundancy operating arm base (2), the soft tail end buffer joint (3) and the rigid-flexible coupling telescopic joint (4) are the components of the rigid-flexible coupling super-redundancy operating arm in the spherical robot. The rigid-flexible coupling super-redundant operating arm is connected with the flexible cable driven expandable spherical shell (1) through the base (2), the tail end of the operating arm is connected with the operating arm through the buffer joint (3), and the rigid connecting rod is replaced by the rigid-flexible coupling telescopic joint (4), so that the whole operating arm forms the super-redundant operating arm with 10 degrees of freedom. The soft tail end buffer joint (3) is a tail joint of the operation arm and comprises an external operation hand grip. The first section of the smart arm (8) is connected with the super-redundant operating arm base (2), and the tail end (9) of the smart arm can be used for supporting single-end unfolding.
The motion principle of the invention is as follows:
under the spherical cruising mode, the robot flexible rope drives the expandable spherical shell (1) to be in a closed state, the spherical robot is used as a mass center change mechanism in a spherical moving state through a super-redundancy operation arm, mass center deviation is generated through rotation of a rigid-flexible coupling telescopic joint (4) based on the principle of gravity moment generated by mass center deviation, and flexible and stable rolling of the robot is realized.
The smart arms (8) on the spherical robot can respectively extend out of the smart arm tail ends (9) at the left end and the right end of the spherical shell to be used as supports in a spherical cruising mode, so that the whole spherical shell is lifted, the robot smart arm operation mode has the characteristics of a ball and legs, the obstacle crossing height is further improved, short-distance gait walking is realized, and the obstacle crossing trafficability is improved; for the obstacle that the vertical height exceeds the radius of the spherical robot and the maximum supportable height of the smart arms, the combination of a plurality of robots is realized through the butt joint function among the smart arms to form an open-chain serial topological structure, so that multi-machine cooperation obstacle surmounting is realized.
The robot can be unfolded through the spherical shell to enter a double-operation-arm operation mode, at the moment, the inner side of the spherical shell is unfolded, so that the solar sail (6) in the spherical shell starts to work to provide energy for the robot, the double-operation arm is supported by the super-redundancy operation arm base (2) and the tail end (9) of the smart arm, the left super-redundancy operation arm and the right super-redundancy operation arm can be operated in a large range in space.
The robot can realize mutual communication with the environment and other robots, the single spherical robot can acquire the positions of other robots through the in-ball antenna (5), the single spherical robot moves to a preset task fixed point respectively through the preset task requirement, the spherical shell is unfolded to enter a double-operation-arm operation mode, and a plurality of robots are mutually matched to realize cooperative operation so as to jointly complete the construction of a complex task of a base under the extreme environment of the moon.
The invention has the advantages and benefits that:
the utility model provides a portable operation spherical robot for moon base is built, replace the function of pendulum with the arm and promote spherical robot's external operation ability, satisfy the internal mechanism function demand through the cooperation between the inside redundant arm of spherical shell, combine the spherical shell that possesses large deformation expansion ability, can make spherical robot can both obtain the promotion by a wide margin in the aspect of obstacle ability and external operation ability when playing self advantage, can realize the mutual cooperation of a plurality of super redundant operation arms under external operating condition, make the robot possess powerful self-protection, obstacle ability and external operation ability, can effectively be to complex tasks such as maintenance on moon surface, inspection. Has great potential advantages and profound research value.
Drawings
In order to more clearly illustrate the technical solution of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described.
FIG. 1 is an internal schematic view of the overall structure of the spherical robot;
FIG. 2 is a schematic view of the spherical robot in a spherical cruise mode;
FIG. 3 is a schematic view of the spherical robot in a smart arm mode of operation;
FIG. 4 is a schematic view of the spherical robot in a dual-arm mode of operation;
the reference numerals in the figures are:
1-flexible rope driven expandable spherical shell 2-rigid-flexible coupling super-redundant operating arm base
4-rigid-flexible coupled telescopic joint of 3-soft tail end buffer joint
5-in-ball antenna 6-in-ball solar sail
7-automatic release and locking mechanism 8-smart arm
9- -smart arm tip
Detailed Description
For a better understanding of the technical solution of the present invention, the following detailed description of the embodiments of the present invention refers to the accompanying drawings. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
As shown in fig. 1, which is an internal schematic view of the overall structure of the robot, the internal schematic view of the robot is better shown, and the deformation process is schematic, and it should be noted that the robot is in an unstable state in this state.
As shown in fig. 2, the robot is in a closed state at this time, so as to ensure that the interior of the robot is isolated from the outside in the state, when the robot needs to be stationary in the state, a gyroscope and an acceleration sensor in the robot can drive a motor of the rigid-flexible coupling telescopic joint (4), so that the robot keeps dynamic balance, and when the robot needs to move in the state, the spherical robot serves as a centroid changing mechanism in the spherical movement state through a super-redundancy operating arm, and flexible and stable rolling of the robot is realized through the homodromous rotation of the rigid-flexible coupling telescopic joint (4).
As shown in fig. 3, the smart arm (8) on the spherical robot is shown in a schematic view of the spherical robot in a smart arm operation mode, and the smart arm ends (9) at the left and right ends of the spherical shell can be respectively extended to serve as supports in a spherical cruising mode to lift the whole sphere, so that the whole robot can be regarded as a two-leg robot, and a gyroscope and an acceleration sensor in the robot can drive a motor of a rigid-flexible coupling telescopic joint (4) to keep dynamic balance of the robot, realize short-distance gait walking through the smart arm (8) and realize step obstacle surmounting of the robot.
As shown in FIG. 4, the spherical robot is shown in a double-operation-arm operation mode, the change process is that the robot reaches a designated position according to the positions of other spherical robots in a spherical cruising mode, based on a pre-input task, an operation base point is determined, the tail ends (9) of the smart arms (8) at two ends extend out and are supported on the ground, then the spherical shell is unfolded through an automatic release and locking mechanism (7) to enable the solar sail (6) in the ball to start to work, at the moment, two super-redundancy operation arms can rely on the super-redundancy operation arm base (2) and the tail ends (9) of the smart arms to serve as supports, so that the left super-redundancy operation arm and the right super-redundancy operation arm can operate in a large range in space.

Claims (5)

1. A mobile, manoeuvrable spherical robot for lunar base construction, characterized by: the flexible cable-driven expandable spherical shell comprises a flexible cable-driven expandable spherical shell (1), a rigid-flexible coupling super-redundant operating arm base (2), a flexible tail end buffer joint (3), a rigid-flexible coupling telescopic joint (4), an intra-spherical antenna (5), an intra-spherical solar sail (6), an automatic release and locking mechanism (7), a smart arm (8) and a smart arm tail end (9); the flexible rope driven expandable spherical shell (1) adopts a armadillo bionic structure, the spherical shell is of a complete spherical structure when rolled up, and an inner spherical solar sail (6) covered on the inner surface of the spherical shell can play a role in absorbing solar energy when expanded; the automatic release and locking mechanism (7) is arranged at the joint of the flexible cable driven expandable spherical shell (1) and is used for locking and releasing the expandable spherical shell; the rigid-flexible coupling super-redundant operating arm base (2), the soft tail end buffer joint (3) and the rigid-flexible coupling telescopic joint (4) are the forming units of the rigid-flexible coupling super-redundant operating arm in the spherical robot; the rigid-flexible coupling super-redundant operating arm is connected with two sides of the flexible cable driven expandable spherical shell (1) through the base (2), the tail end of the operating arm is connected with the operating arm through the buffer joint (3), and the rigid connecting rod is replaced by the rigid-flexible coupling telescopic joint (4), so that the whole operating arm forms the super-redundant operating arm with 10 degrees of freedom; the tail end (9) of the smart arm is a unfolding supporting mechanism and is connected with the spherical shell through the smart arm (8); the ball antenna (5) is connected with the inner side of the rigid-flexible coupling super redundant operation arm base (2) and can be used for expanding communication signals when the base (2) is unfolded.
2. A mobile, manoeuvrable spherical robot for lunar base construction as claimed in claim 1 wherein: the robot has three modes of operation: the robot comprises a spherical cruising mode, a smart arm operation mode and a double-operation-arm operation mode, wherein in the spherical cruising mode, a spherical shell of the robot is in a closed state, and the robot rolls on the basis of the principle of gravity moment generated by centroid offset through a first-stage rigid-flexible coupling telescopic joint (4) on a super-redundancy operation arm.
3. A mobile, manoeuvrable spherical robot for lunar base construction as claimed in claim 1 wherein: in the smart arm operation mode, the device has the ball-leg characteristics so as to improve the obstacle crossing height, and the obstacle crossing of the smart arm with smaller vertical height can be completed through rolling of the spherical cruising mode or cooperation of the smart arm in the smart arm operation mode; for the obstacle that the vertical height exceeds the radius of the spherical robot and the maximum supportable height of the smart arms, the combination of a plurality of robots is realized through the butt joint function among the smart arms to form an open-chain serial topological structure, so that multi-machine cooperation obstacle surmounting is realized.
4. A mobile, manoeuvrable spherical robot for lunar base construction as claimed in claim 1 wherein: under the double-operation-arm operation mode, the spherical shell of the robot is unfolded, so that the solar sail (6) in the spherical shell starts to work to provide energy for the robot, and the double-operation-arm is supported by the super-redundancy operation-arm base (2) and the tail end (9) of the smart arm, so that the left super-redundancy operation arm and the right super-redundancy operation arm can realize external large-range operation in space.
5. A mobile, manoeuvrable spherical robot for lunar base construction as claimed in claim 4 wherein: the robots can communicate with other robots, and in a double-operation-arm operation mode, multiple robots can cooperate with each other to realize cooperative operation, so that complex tasks of building a base under the extreme environment of the moon are completed together.
CN202210547443.7A 2022-05-18 2022-05-18 A portable operation spherical robot for moon base is built Active CN114939877B (en)

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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101314222A (en) * 2008-05-12 2008-12-03 北京邮电大学 Spherical robot having visual sensation and arms on both sides
CN106627007A (en) * 2016-10-31 2017-05-10 苏州大学 Amphibious spherical robot of changeable structure
CN206218046U (en) * 2016-10-26 2017-06-06 中国航天空气动力技术研究院 Spherical transfer robot
WO2017105294A1 (en) * 2015-12-14 2017-06-22 Игорь Викторович РЯДЧИКОВ Two-legged walking robot
CN107187509A (en) * 2017-05-17 2017-09-22 上海大学 A kind of ball shape robot with walking function
CN109331477A (en) * 2018-12-11 2019-02-15 佛山科学技术学院 One kind can the bionical fighter toy of throwing ball julid
CN109774807A (en) * 2019-03-13 2019-05-21 北京邮电大学 Double working modes based on super redundant mechanical arm can Moving high speed scroll three-drive spherical robot
CN113212579A (en) * 2021-05-10 2021-08-06 北京邮电大学 Ball wheel leg composite mobile robot capable of being operated outwards
CN214057144U (en) * 2020-12-31 2021-08-27 内蒙古工业大学 Amphibious deformable spherical six-legged robot
CN113788082A (en) * 2021-09-17 2021-12-14 山东科技大学 Reconfigurable spherical robot, control system and control method thereof
CN114227660A (en) * 2021-12-17 2022-03-25 北京空间飞行器总体设计部 Rigid-flexible coupling super-redundancy intelligent sensing mechanical arm and use method thereof

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101314222A (en) * 2008-05-12 2008-12-03 北京邮电大学 Spherical robot having visual sensation and arms on both sides
WO2017105294A1 (en) * 2015-12-14 2017-06-22 Игорь Викторович РЯДЧИКОВ Two-legged walking robot
CN206218046U (en) * 2016-10-26 2017-06-06 中国航天空气动力技术研究院 Spherical transfer robot
CN106627007A (en) * 2016-10-31 2017-05-10 苏州大学 Amphibious spherical robot of changeable structure
CN107187509A (en) * 2017-05-17 2017-09-22 上海大学 A kind of ball shape robot with walking function
CN109331477A (en) * 2018-12-11 2019-02-15 佛山科学技术学院 One kind can the bionical fighter toy of throwing ball julid
CN109774807A (en) * 2019-03-13 2019-05-21 北京邮电大学 Double working modes based on super redundant mechanical arm can Moving high speed scroll three-drive spherical robot
CN214057144U (en) * 2020-12-31 2021-08-27 内蒙古工业大学 Amphibious deformable spherical six-legged robot
CN113212579A (en) * 2021-05-10 2021-08-06 北京邮电大学 Ball wheel leg composite mobile robot capable of being operated outwards
CN113788082A (en) * 2021-09-17 2021-12-14 山东科技大学 Reconfigurable spherical robot, control system and control method thereof
CN114227660A (en) * 2021-12-17 2022-03-25 北京空间飞行器总体设计部 Rigid-flexible coupling super-redundancy intelligent sensing mechanical arm and use method thereof

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
An Autonomous Positioning and Navigation System for Spherical Mobile Robot;Kang Hou, Hanxu Sun , Qingxuan Jia , Yanheng Zhang;Procedia Engineering;Volume 29;Pages 2556-2561 *
新型变结构球形机器人运动分析;孙汉旭,赵伟,张延恒;机械工程学报;第49卷(第19期);第40-47页 *
星球表面着陆巡视一体化探测机器人研究进展;路达,刘金国,高海波;航空学报;第42卷(第1期);523742(1-17页) *

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