RO128018A0

RO128018A0 - Parallel mechanism with six mobility degrees for robot construction

Info

Publication number: RO128018A0
Application number: ROA201200465A
Authority: RO
Inventors: Liviu Moldovan
Original assignee: Universitatea ''petru Maior'' Din Târgu Mureş
Priority date: 2012-06-22
Filing date: 2012-06-22
Publication date: 2012-12-28
Also published as: RO128018B1

Abstract

The invention relates to a spatial parallel mechanism with six degrees of mobility for the construction of robots intended for handling or processing operations. According to the invention, the mechanism comprises two hexagonal platforms (1 and 9), namely a fixed lower platform and a mobile upper platform, linked by six kinematic chains articulated at the two extremities to the two hexagonal platforms (1 and 9), where to the upper mobile platform (9) a clamping mechanism can be attached, each of the kinematic chains consisting of two elements articulated to each other by some ball joints (4), the first element consisting of an assembly (2-3) of variable length and the second element being a bar (5) of a fixed length, through the assembly (2-3), at the lower end, the kinematic chains forming a translation couple and at the upper end, the bars (5) being coupled to the mobile platform (9) by some cardan joints (6-7-8), the parallel mechanism being driven, by means of the six translation couples, by some rotary electric motors (12) which thereby control the lengths of the kinematic chains, an inclination angle ( λ) of the translation couples being variable in the plane normal to the lower fixed platform, placed in parallel, at a preset distance from the homologous side of the hexagon, by the inclination of a support (10) rotating about a cylindrical hinge (11), the inclination angle of the support (10) being fixed, by means of a screw (13), by a support (14) integral with the fixed platform (1), the mobile platform (9) having six degrees of mobility being able to move at high speeds and accelerations, and having high rigidity which confers it the capacity to perform high precision motion.

Description

Invenția se referă la un mecanism paralel spațial cu șase grade de mobilitate, utilizabil pentru construirea roboților paraleli destinați operațiilor de manipulare sau de procesare.The invention relates to a parallel space mechanism with six degrees of mobility, usable for the construction of parallel robots intended for handling or processing operations.

După cum se cunoaște, mecanismele paralele sunt acționate de motoare dispuse pe batiu în paralel, ceea ce are ca efect reducerea masei mecanismului aflat în mișcare și creșterea rigidității sale, ceea ce îi conferă capacitatea de a executa deplasări de înaltă precizie cu viteze și accelerații mari. Principalul dezavantaj al mecanismelor paralele îl constituie spațiul restrâns de lucru.As it is known, the parallel mechanisms are driven by motors arranged on the frame in parallel, which has the effect of reducing the mass of the moving mechanism and increasing its rigidity, which gives it the ability to perform high-precision travel at high speeds and accelerations. . The main disadvantage of parallel mechanisms is the limited working space.

în scopul construirii roboților paraleli sunt cunoscute mai multe mecanisme spațiale cu bare articulate, care au până la șase grade de mobilitate.In order to build parallel robots, several space mechanisms with articulated bars are known, which have up to six degrees of mobility.

Un astfel de mecanism este descris în brevetul US 5333514, care este alcătuit dintr-o platformă fixă, trei lanțuri cinematice articulate la bază la o distanță predeterminată în jurul centrului platformei fixe și o platformă mobilă de care sunt articulate cele trei lanțuri cinematice și pe care este montat un sistem de prindere. Fiecare lanț cinematic este acționat de câte o pereche de motoare rotative montate în locașuri degajate în platforma fixă. Lanțurile cinematice se compun din câte două perechi de bare articulate între ele. Dezavantajul acestui mecanism constă în aceea că are un spațiu de lucru restrâns.Such a mechanism is described in US Pat. No. 53,33514, which consists of a fixed platform, three kinematic chains articulated at the base at a predetermined distance around the center of the fixed platform and a mobile platform from which the three kinematic chains are articulated and on which a fastening system is installed. Each powertrain is driven by a pair of rotary motors mounted in recesses in the fixed platform. The kinematic chains consist of two pairs of bars articulated between them. The disadvantage of this mechanism is that it has a limited workspace.

Problema pe care o rezolvă invenția constă în realizarea unui mecanism paralel spațial, cu șase grade de mobilitate, care are o structură cinematică simplă și care se folosește la construcția roboților paraleli.The problem solved by the invention consists in the realization of a parallel spatial mechanism, with six degrees of mobility, which has a simple kinematic structure and which is used in the construction of parallel robots.

Mecanismul paralel pentru construcția roboților, conform invenției (Figura 1), este format dintr-o platformă hexagonală fixă 1, situată la bază (batiu) și o platformă superioară mobilă 9. Cele două platforme sunt legate prin șase lanțuri cinematice, articulate la cele două extremități de cele două platforme. De platforma superioară se poate atașa un mecanism de prindere. Platforma mobilă are șase grade de mobilitate.The parallel mechanism for the construction of the robots, according to the invention (Figure 1), consists of a fixed hexagonal platform 1, located at the base (frame) and a movable upper platform 9. The two platforms are connected by six kinematic chains, articulated at the two extremities of the two platforms. A clamping mechanism can be attached to the upper platform. The mobile platform has six degrees of mobility.

Lanțurile cinematice (Figura 1) sunt formate fiecare din câte două elemente articulate între ele prin articulații sferice 4. Primul element este format din ansamblulThe kinematic chains (Figure 1) are formed each of two elements articulated to each other by spherical joints 4. The first element consists of the assembly

2-3 de lungime variabilă, iar al doilea element este bara 5 de lungime fixă. Prin ansamblul 2, 3 la capătul inferior, lanțurile cinematice formează o cuplă de translație. La capătul superior barele 5 sunt cuplate la platforma mobilă prin articulații cardanice (6-7-8), care au arborii de intrare 6 fixați prin înfiletare de barele 5 și arborii de ieșire 8 fixați prin înfiletare de platforma superioară 9. Cei doi arbori 6, 8 ai articulației cardanice sunt articulați cilindric de crucea cardanică 7.2-3 of variable length, and the second element is the bar 5 of fixed length. Through assembly 2, 3 at the lower end, the kinematic chains form a translation coupling. At the upper end the bars 5 are coupled to the mobile platform by cardan joints (6-7-8), which have the input shafts 6 fixed by screwing to the bars 5 and the output shafts 8 fixed by screwing to the upper platform 9. The two shafts 6 , 8 of the cardan joint are cylindrically articulated by the cardan cross 7.

Mecanismul paralel este acționat prin intermediul celor șase cuple de translație, cu motoare electrice rotative 12, care în acest fel controlează lungimile lanțurilor cinematice. Unghiul de înclinare al cuplelor de translație λ, este variabil în planul normal la platforma fixă, situat paralel la o distanță predeterminată de latura omoloagă a hexagonului, prin înclinarea suportului 10 care se rotește în jurul articulației cilindrice 11, cu unghiul Xj față de paralela la platforma fixă de la bază. Fixarea unghiului de înclinare al suportului 10 are loc prin șurubul 13 de suportul 14, care este corp comun cu platforma fixă 1.The parallel mechanism is operated by means of the six translation couplings, with rotary electric motors 12, which in this way control the lengths of the kinematic chains. The angle of inclination of the translation torques λ, is variable in the normal plane at the fixed platform, located parallel to a predetermined distance from the homologous side of the hexagon, by tilting the support 10 rotating around the cylindrical joint 11, with the angle Xj to the parallel to fixed platform at the base. The fixing of the angle of inclination of the support 10 takes place through the screw 13 of the support 14, which is a common body with the fixed platform 1.

Așa cum se arată în figura 2, cele șase lanțuri cinematice sunt dispuse pe un contur hexagonal, pe platforma fixă de la bază 1.As shown in Figure 2, the six kinematic chains are arranged on a hexagonal contour on the fixed platform at the base 1.

ιχ- 2 Ο 1 2 - Ο Ο 4 θ 5 - Ζ Ζ -06’ Ζ01Ζιχ- 2 Ο 1 2 - Ο Ο 4 θ 5 - Ζ Ζ -06 ’Ζ01Ζ

Acționarea lanțului cinematic (Figura 3) se realizează prin motorul electric rotativ 12, fixat de suportul 10 prin șuruburile 15. Mișcarea este transmisă de la motorul 12 la șurubul conducător 21 prin cuplajul elastic 16, 18 fixat de axul motorului și șurubul conducător prin șuruburile 17, 19. Șurubul conducător 21 este montat prin strângere pe inelul interor al rulmentului cu bile pe două rânduri 28, care este fixat în carcasa 22 prin inelul elastic 27.The drive of the kinematic chain (Figure 3) is performed by the rotary electric motor 12, fixed to the support 10 by the screws 15. The movement is transmitted from the motor 12 to the guide screw 21 through the elastic coupling 16, 18 fixed to the motor shaft and the guide screw through the screws 17 19. The guide screw 21 is mounted by tightening on the inner ring of the two-row ball bearing 28, which is fixed in the housing 22 by the elastic ring 27.

Mișcarea de rotație a șurubului conducător 21 este transformată în mișcarea de rotație a piuliței 20, pe care este fixată pana 26, care translatează în canalul liniar din carcasa 22, fixată de suportul 10 prin șuruburile 29. Pe carcasa 22 este fixat capacul 25 prin șuruburile 24. Pe orificiul carcasei este montat inelul de pâslă 23.The rotational movement of the guide screw 21 is transformed into the rotational movement of the nut 20, on which it is fixed up to 26, which translates into the linear channel in the housing 22, fixed to the support 10 by the screws 29. The cover 25 is fixed on the housing 22 by the screws 24. The felt ring 23 is mounted on the hole in the housing.

Gradul de mobilitate al mecanismului se calculează după următoarea formulă: M = 6n-3C3-2C2-Cl=6-7-3-6-2’6-6 = 42-36 = 6 în care n = 6 + 6+ l = 13 este numărul elementelor mobile 3, 5, 9; C3 = 6 este numărul cuplelor sferice 4; C2 = 6 este numărul cuplelor cardanice 6-7-8; iar CI =6 este numărul cuplelor prismatice 2-3.The degree of mobility of the mechanism is calculated according to the following formula: M = 6n-3C3-2C2-Cl = 6-7-3-6-2'6-6 = 42-36 = 6 where n = 6 + 6+ l = 13 is the number of moving elements 3, 5, 9; C3 = 6 is the number of spherical couples 4; C2 = 6 is the number of cardan torques 6-7-8; and CI = 6 is the number of prismatic couples 2-3.

Mecanismul paralel conform invenției prezintă următoarele avantaje:The parallel mechanism according to the invention has the following advantages:

- are o structură cinematică simplă;- has a simple kinematic structure;

- are un spațiu de lucru mai mare aecât al mecanismelor paralele existente, care poate fi modelat prin înclinări diferite ale lanțurilor cinematice motoare;- has a larger working space than the existing parallel mechanisms, which can be modeled by different inclinations of the motor kinematic chains;

- are rigiditate mare deoarece motoarele sunt fixate la bază, ceea ce îi conferă capacitatea de a executa deplasări de înaltă precizie;- it has high rigidity because the motors are fixed to the base, which gives it the ability to perform high precision movements;

- are greutate redusă, ceea ce contribuie la diminuarea consumului energetic în timpul funcționării și a costurilor de fabricație;- is lightweight, which helps to reduce energy consumption during operation and manufacturing costs;

- poate executa deplasări cu viteze și accelerații mari.- can travel at high speeds and accelerations.

Claims

1. Parallel mechanism with articulated bars for the construction of handling and processing robots characterized in that it consists of a fixed hexagonal platform (1) and a mobile hexagonal platform (9), joined by six kinematic chains driven by circular motors (12) mounted on the fixed platform, the movement of which is transformed into a linear drive. at the end of the linear drives (2, 3) are articulated spherically (4) the bars (5), which are articulated gimbal (67-8) at the other end of the movable platform (9).

The mechanism according to claim 1, is characterized in that the linear drives can be inclined in the normal plane to the fixed platform at the base, located parallel to a predetermined distance from the homologous side of the hexagon, with angles λ; compared to normal, which allows it to configure an enlarged workspace, suitable for the application in which it is used.