CN114802507A

CN114802507A - Omnidirectional mobile robot based on Schatz mechanism

Info

Publication number: CN114802507A
Application number: CN202210409295.2A
Authority: CN
Inventors: 刘然; 唐己明; 姚燕安; 姚舜
Original assignee: Beijing Jiaotong University
Current assignee: Beijing Jiaotong University
Priority date: 2022-04-19
Filing date: 2022-04-19
Publication date: 2022-07-29
Anticipated expiration: 2042-04-19
Also published as: CN114802507B

Abstract

An omnidirectional mobile robot based on a Schatz mechanism is characterized in that: consists of four identical drive units (A, B, C, D) and a carrier platform (E); take the first driving unit as an example. Each driving unit comprises first to sixth connecting rods (A1, A3, A4, A9, A10 and A11) of a Schatz mechanism, first to fourth modules (A5, A6, A7 and A8) of an Oloid special-shaped wheel, a motor (A2) and a driven rotating pair (A12). The carrying platform is an octagonal plate with four long sides and four short sides; the four long edges are respectively positioned at the four corners of the carrying platform, and both sides of each long edge are respectively provided with a through hole for fixedly connecting the first connecting rod with the carrying platform; the carrier platform has a through hole (E1) in the center for connecting the motor power circuit. Under the condition of the same rotating speed, the advancing direction of the robot is related to the rotation direction collocation of the four driving unit motors.

Description

Omnidirectional mobile robot based on Schatz mechanism

Technical Field

The invention relates to the field of mobile robots, in particular to a mobile robot with omnidirectional movement and obstacle crossing capability based on a Schatz mechanism.

Background

In recent years, the technology of mobile robots has been remarkably developed, and robots have entered human lives in many fields. The traditional mobile robot is more and more difficult to meet the requirements of tasks such as transportation, investigation, rescue and the like due to the incompleteness of the motion of the traditional mobile robot. The omnidirectional mobile robot has the omnidirectional movement capability, so that the omnidirectional mobile robot has stronger environmental adaptability. Which can move in a narrow, complex space. Different types of omnidirectional mobile robots can be constructed based on different omnidirectional mechanisms, such as a 6-foot wheel-leg composite omnidirectional mobile robot proposed by the U.S. space agency, ATHLETE, and omnidirectional mobile robots based on omnidirectional wheels (mecanum wheels) or universal wheels. In the case of a foot-type omnidirectional mobile robot, an open chain mechanism is often used, and a plurality of motors are required. This not only increases the size of the robot itself, but also increases the complexity of the control system. The omnidirectional mobile robot based on the omnidirectional wheels (mecanum wheels) or the universal wheels is limited by the obstacle crossing capability, the abrasion and other problems, and is mainly applied to indoor environments with good road surface conditions.

The Schatz mechanism is used as a spatial single-degree-of-freedom closed chain connecting rod mechanism and has the characteristics of high rigidity and few degrees of freedom. Utilizing the spatial reciprocating motion of the mechanism link, Yaoan and Yashun et al proposed a series of mobile robots based on Schatz mechanism, such as a multi-legged deformable robot based on Schatz mechanism disclosed in Chinese patent application CN202010070407.7 and a contour wheel type robot based on Schatz mechanism disclosed in Chinese patent application CN 202010230165.3. All of them use the Schatz mechanism as a driving unit and perform contour curve design for different connecting rods. The control model of the robot is simplified, and the robot is endowed with good terrain adaptability. However, the robot does not have omnidirectional movement capability.

The Oloid surface is an expandable surface. Proposed by the German scientist Paul Schatz. A driving unit formed by combining the curved surface and the Schatz mechanism has the potential of constructing an omnidirectional mobile robot by utilizing the consistent motion rule of the curved surface and the Schatz mechanism.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: 1. the problem that the current mobile robot based on a multi-module Schatz mechanism cannot realize omnidirectional movement is solved. 2. The appearance of the Oloid curved surface is reformed into a special-shaped wheel, and the special-shaped wheel is combined with a Schatz mechanism, so that the robot with the capabilities of omnidirectional movement and obstacle crossing is invented.

The technical scheme of the invention is as follows: an omnidirectional mobile robot based on a Schatz mechanism. The method is characterized in that: the robot comprises a first driving unit, a second driving unit, a third driving unit, a fourth driving unit and an object carrying platform, wherein the first driving unit, the second driving unit and the fourth driving unit are formed by combining a Schatz mechanism and an Oloid special-shaped wheel. The four driving units are completely consistent and distributed on four corners of the carrying platform. Each driving unit comprises a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a motor and a driven rotating pair.

The first connecting rod is a square tube, and through holes for passing through the output shaft of the motor and the driven rotating shaft, the motor and three mounting holes for passing through the driven rotating shaft are evenly distributed at two ends of the front side of the first connecting rod. The back side is provided with a hollow groove for installing a motor and a driven rotating pair. The motor and the driven revolute pair are linked with the first connecting rod by using bolts. In addition, two through holes are respectively arranged at the two ends of the upper side and the lower side of the first connecting rod. Through the through hole, the first connecting rod is connected with the carrying platform in a bolt and nut mode.

The second connecting rod is completely the same as the sixth connecting rod and is of a square block structure. The lower end surface of the connecting rod is provided with a D-shaped connecting hole which is respectively connected with the output shaft of the motor and the rotating shaft of the driven rotating pair. The lower side of the front end surface is provided with a through hole which is matched with the through holes on the motor and the driven shaft. The second connecting rod and the sixth connecting rod are connected with the motor or the driven shaft in a bolt and nut mode through the through hole. The upper side of the front end surface is provided with a through hole, and two ends of the through hole are respectively provided with a circular groove. And the second connecting rod and the sixth connecting rod are respectively matched with the third connecting rod and the fifth connecting rod to form a rotary joint in a mode of matching the bolts with the bearings and fastening the nuts through the through holes. The circular groove is used for positioning and mounting the bearing.

The third connecting rod is completely the same as the fifth connecting rod and is of a square block structure. The bottom of the front end surface is provided with a through hole, and the upper part of the front end surface is provided with a notch; the upper side of the left end surface is provided with a through hole, and the lower side is provided with a notch. Wherein, the larger through hole is matched with the through hole at the upper side of the front end surface of the second or sixth connecting rod to form a revolute pair. Two end faces of the through hole at the other end are respectively provided with a slotted hole, and the third connecting rod and the fifth connecting rod are connected with the fourth connecting rod in a mode of matching the through hole with a bearing by using a bolt and fastening the through hole by using a nut to carry out axial positioning.

The fourth connecting rod is a hollow square tube, and through holes which are perpendicular to each other are formed in the two ends of the fourth connecting rod and are respectively connected with the third connecting rod and the fifth connecting rod.

The Oloid special-shaped wheel is formed by reforming an Oloid curved surface. Two through holes are designed at the central positions of two circles constructing the Oloid curved surface, a rotating pair is formed by using a bolt and a bearing in a matching mode, and a nut is used for carrying out axial positioning. And the Oloid special-shaped wheel is connected with the third connecting rod, the fourth connecting rod and the fifth connecting rod at the positions of the two through holes. And the Oloid surface is symmetrically divided into four completely identical modules. The four modules are respectively named as: the device comprises a first module, a second module, a third module and a fourth module. And adjacent modules are connected through bolts and nuts.

The driven revolute pair is of a cylindrical block structure, a group of connecting holes are formed in the circular base and used for being fixedly connected with the first connecting rod through bolts, and the small cylindrical shaft is a driven rotating shaft and connected with the sixth connecting rod.

The object carrying platform is an octagonal plate with four long edges and four short edges. The four long edges are respectively positioned at four corners of the carrying platform, and two sides of each long edge are respectively provided with a through hole for fixedly connecting the first connecting rod with the carrying platform. The center of the loading platform is provided with a through hole for connecting a motor power circuit.

An omnidirectional mobile robot based on a Schatz mechanism has the advantages that the rotating speeds of motors of a first driving unit and a second driving unit are the same, and the rotating directions are opposite; the motor rotating speeds of the third driving unit and the fourth driving unit are the same, and the rotating directions are opposite; the motor of the first and third driving units are rotated in the same direction, and the motor of the second and fourth driving units are rotated in the same direction. The robot moves straight to the front or the back, and the moving speed is positively correlated with the rotating speed of the motor.

An omnidirectional mobile robot based on a Schatz mechanism has the same motor rotating speed and the same steering direction of first to fourth driving units. The robot can realize the transverse movement of the left side and the right side, and the moving speed is positively correlated with the rotating speed of the motor.

When the rotating speeds of motors of first to fourth driving units are the same, and the motor rotating directions of the first and third driving units are the same and are opposite to the motor rotating directions of the second and fourth driving units, the robot can move obliquely, and the moving speed is positively correlated with the rotating speed of the motors.

Drawings

FIG. 1 is a three-dimensional overall view of an omnidirectional mobile robot based on Schatz mechanism

FIG. 2 is an overall three-dimensional view of the first drive unit

FIG. 3 three-dimensional view of the first link

FIG. 4 is a three-dimensional view of a second link

FIG. 5 three-dimensional view of the third link

FIG. 6A three-dimensional view of a fourth link

FIG. 7 is an overall three-dimensional view of an Oloid contour wheel

FIG. 8 is a three-dimensional view of a first module of an Oloid contour wheel

FIG. 9 is a diagram showing the assembly relationship between the first and second modules and the third and fourth links of the contour wheel

FIG. 10 three-dimensional view of a driven revolute pair

FIG. 11 three-dimensional view of the carrier platform

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

An omnidirectional robot based on the Schatz mechanism is shown in fig. 1 and consists of a first driving unit, a second driving unit, a third driving unit, a fourth driving unit, four driving units (A, B, C, D) and an object platform (E).

Embodiments of the invention:

as shown in fig. 2, the first driving unit (a) is exemplified. Each driving unit comprises first to sixth connecting rods (A1, A3, A4, A9, A10 and A11) of a Schatz mechanism, first to fourth modules (A5, A6, A7 and A8) of an Oloid special-shaped wheel, a motor (A2) and a driven revolute pair (A12).

The first connecting rod (A1) is a square tube, as shown in figure 3. The two ends of the front side of the motor are uniformly provided with three mounting holes for a motor output shaft and through holes (A1-1 and A1-2) for the driven rotating shaft to pass through, the motor and the driven rotating shaft. The back side is provided with a hollow groove for installing a motor and a driven rotating pair. The motor and the driven revolute pair are linked with the first connecting rod by using bolts. In addition, two ends of the upper side and the lower side of the first connecting rod are respectively provided with a through hole (A1-3 and A1-4). Through these through holes, the first link is linked with the carrier platform in the form of bolts and nuts.

The second link (A3) is identical to the sixth link (A11), and has a square block structure, as shown in FIG. 4. Taking the second connecting rod (A3) as an example, a D-shaped connecting hole (A3-1) is arranged on the lower end surface of the second connecting rod and is connected with the output shaft of the motor. The lower side of the front end surface is provided with a through hole (A3-2) which is matched with the through holes on the motor and the driven shaft. The second connecting rod and the sixth connecting rod are connected with the motor or the driven shaft in a bolt and nut mode through the through hole. The upper side of the front end surface is provided with a through hole (A3-3), and two ends of the through hole are respectively provided with a circular groove (A3-4). The second and sixth connecting rods (A3, A11) are respectively matched with the third and fifth connecting rods (A4, A10) to form a rotary joint by matching the through holes with the bearings by using bolts and fastening the bolts by nuts. The circular groove is used for positioning and mounting the bearing.

The third link (A4) is identical to the fifth link (A10), and is a square block structure, as shown in FIG. 5. Taking the third connecting rod (A4) as an example, a smaller through hole (A4-1) is arranged at the bottom of the front end surface of the third connecting rod, and a notch is arranged at the upper part of the front end surface; the upper side of the left end surface is provided with a larger through hole (A4-2), and the lower side is provided with a notch. Wherein, the larger through hole (A4-2) is matched with the through hole on the upper side of the front end surface of the second or sixth connecting rod to form a revolute pair. Two end faces of the through hole (A4-1) with the smaller other end are respectively provided with a slotted hole, and the third connecting rod (A4), the fifth connecting rod (A10) and the fourth connecting rod (A9) are linked in a mode that the through hole is matched with a bearing through a bolt and is fastened through a nut for axial positioning.

The fourth connecting rod (A9) is a hollow square tube, as shown in figure 6. Two ends of the connecting rod are provided with mutually vertical through holes (A9-1 and A9-2) which are respectively linked with the third connecting rod and the fifth connecting rod.

The Oloid profile wheel is shown in fig. 7. The solar module is assembled by a first module, a5, a6, a7 and A8, wherein the four modules are identical. Taking the first module as an example, the structure is shown in fig. 8. The left through hole (A5-1) of the first module corresponds to the left through hole (A7-1) of the third module, and the two are connected through bolts and nuts. The right through hole (A5-2) of the first module corresponds to the right through hole (A7-2) of the fourth module and is linked through a bolt and a nut. As shown in fig. 9, the first and second modules (a5, a6) are linked with the third and fourth links (a4, a9) by forming a revolute pair by means of a bolt and a bearing, and performing axial positioning by means of a nut and a washer.

The driven revolute pair (A12) is of a cylindrical block structure, as shown in figure 10. A group of connecting holes are formed in the circular base (A12-1) and are fixedly connected with the first connecting rod (A1) through bolts, and the small cylindrical shaft (A12-2) is a driven rotating shaft and is connected with the sixth connecting rod (A11).

The carrier platform (E) is an octagonal plate with four long sides and four short sides, as shown in fig. 11. The four long edges are respectively positioned at the four corners of the object carrying platform, and two sides of each long edge are respectively provided with a through hole for fixedly connecting the first connecting rod (A1) with the object carrying platform (E). The carrier platform has a through hole (E1) in the center for connecting the motor power circuit.

Claims

1. An omnidirectional mobile robot based on a Schatz mechanism is characterized in that: consists of a first to a fourth drive unit (A, B, C, D) and a stage (E), the four drive units being identical; taking as an example a first drive unit (a), each of said drive units comprises Schatz mechanism first to sixth links (a1, A3, a4, a9, a10, a11), Oloid profile wheel first to fourth modules (a5, a6, a7, A8), a motor (a2), a driven revolute pair (a 12);

taking the example of a first drive unit (a), each of the drive units comprises first to sixth links (a1, A3, a4, a9, a10, a11) of a Schatz mechanism, first to fourth modules (a5, a6, a7, A8) of an Oloid wheel, a motor (a2) and a driven revolute pair (a 12);

the first connecting rod (A1) is a square tube, through holes (A1-1 and A1-2) for passing through a motor output shaft and a driven rotating shaft, and a motor and a driven rotating shaft are uniformly distributed at two ends of the front side of the first connecting rod, a hollow groove is formed in the rear side face of the first connecting rod so as to facilitate installation of the motor and the driven rotating pair, the motor and the driven rotating pair are connected with the first connecting rod by bolts, in addition, through holes (A1-3 and A1-4) are respectively formed at two ends of the upper side and the lower side of the first connecting rod, and the first connecting rod is connected with the loading platform in a bolt and nut mode through the through holes;

the second connecting rod (A3) is identical to the sixth connecting rod (A11) and is a square block structure, taking the second connecting rod (A3) as an example, a D-shaped connecting hole (A3-1) is arranged on the lower end surface of the motor and is connected with the output shaft of the motor, a through hole (A3-2) is arranged at the lower side of the front end surface of the motor and is matched with the through holes on the motor and the driven shaft, the second connecting rod and the sixth connecting rod are connected with the motor or the driven shaft by the through hole in a bolt and nut mode, the upper side of the front end surface is provided with a through hole (A3-3), and two ends of the through hole are respectively provided with a circular groove (A3-4), the second and the sixth connecting rods (A3, A11) are respectively matched with the third and the fifth connecting rods (A4, A10) to form a rotary joint by using bolts to be matched with the bearings through the through holes and fastening the bolts and the nuts, and the circular grooves are used for positioning and installing the bearings;

the third connecting rod (A4) and the fifth connecting rod (A10) are completely the same and are of a square block structure, taking the third connecting rod (A4) as an example, a small through hole (A4-1) is formed in the bottom of the front end face of the third connecting rod, a notch is formed in the upper portion of the front end face, a large through hole (A4-2) is formed in the upper side of the left end face, a notch is formed in the lower side of the left end face, the large through hole (A4-2) is matched with the through hole in the upper side of the front end face of the second or sixth connecting rod to form a revolute pair, two slotted holes are formed in two end faces of the small through hole (A4-1) at the other end, and the third and fifth connecting rods (A4 and A10) are connected with the fourth connecting rod (A9) in an axial positioning mode of using bolts and bearings for fastening nuts;

the fourth connecting rod (A9) is a hollow square tube, and two ends of the fourth connecting rod (A9) are provided with through holes (A9-1 and A9-2) which are perpendicular to each other and are respectively connected with the third connecting rod and the fifth connecting rod;

the Oloid special-shaped wheel is formed by assembling a first module, a second module, a third module, a fourth module, a fifth module, a sixth module, a seventh module, a sixth module, a seventh module, a eleventh module, a sixth module, a fifth module, a sixth module, a seventh module, a fifth module, a module;

the driven revolute pair (A12) is of a cylindrical block structure, a group of connecting holes are formed in the circular base (A12-1) and are fixedly connected with the first connecting rod (A1) through bolts, and the small cylindrical shaft (A12-2) is a driven rotating shaft and is connected with the sixth connecting rod (A11);

the loading platform (E) is an octagonal plate with four long edges and four short edges, the four long edges are respectively positioned at four corners of the loading platform, and two sides of each long edge are respectively provided with a through hole for fixedly connecting the first connecting rod (A1) with the loading platform (E). The carrier platform has a through hole (E1) in the center for connecting the motor power circuit.

2. The omnidirectional mobile robot based on the Schatz mechanism of claim 1, wherein: the motor rotating speeds of the first driving unit and the second driving unit are the same, and the rotating directions are opposite; the motor rotating speeds of the third driving unit and the fourth driving unit are the same, and the rotating directions are opposite; the motors of the first and third driving units are in the same rotation direction, the motors of the second and fourth driving units are in the same rotation direction, the robot moves straight ahead or behind, and the moving speed is in positive correlation with the rotating speed of the motors; when the motor rotating speeds of the first to fourth driving units are the same as the rotating direction, the robot can realize transverse movement on the left side and the right side, and the moving speed is positively correlated with the motor rotating speed; when the motor rotating speeds of the first to fourth driving units are the same, and the motor rotating directions of the first and third driving units are the same and opposite to the motor rotating directions of the second and fourth driving units, the robot can move in an inclined manner, and the moving speed is positively correlated with the motor rotating speed.