Analyss on the Workspace of Sx-degrees-of-freedom Industral Robot Based on AutoCAD Jn-quan L 1, Ru Zhang 1,a, Fang Cu 1, Q Guan 1 and Yang Zhang 1 1 School of Automaton, Bejng Unversty of Posts and Telecommuncatons, 100876 Bejng, Chna Abstract Ths research dscusses the workspace of the ndustral robot wth sx degrees of freedom(6-dof) based on AutoCAD platform Based on the analyss of the overall confguraton of the robot, ths research establshes the knematc mathematcal model of the ndustral robot by usng DH parameters, and then solves the workspace of the robot consequently In the AutoCAD, Auto Lsp language program s adopted to smulate the twodmensonal(2d) and three-dmensonal(3d) space of the robot Software user nterface s wrtten by usng the dalog box control language of Vsual LISP At last, the research analyzes the trend of the shape and drecton of the workspace when the length and angle range of the robot are changed Ths research lays the foundaton for the desgn, control and plannng of ndustral robots 1 Introducton At present, researches from Chna and abroad on the workspace of ndustral robots have made some achevements [1-] The study of workspace of robot s nclned to use Monte Carlo method [5-7] Hou Yule [8] proposes a method for the workspace boundary extracton called lmt fxed nterval angle, based on the prncples of bar lmt combned wth fxed jont varable Tan Habo [9] et al analyze manpulator's workspace by usng Monte Carlo method and brngs adaptve-dvded mesh method to calculate the volume of workspace Y Jun [10]et al develop dynamc smulaton system of robot based on AutoCAD In ths research, robot knematcs model by DH parameter method s mproved, usng Auto Lsp programmng language to acheve sx-degrees-of-freedom ndustral robot workspace smulaton The nfluence of structure parameters on the shape and poston of workspace and poston s analyzed Ths method also provdes a powerful help for the desgn and research of ndustral robot 2 Descrpton of 6-DOF ndustral robot workspace Accordng to the modfed DH parameter, the sx-degree-of-freedom robot lnk coordnate system s establshed See Fgure 1 a Correspondng author : zhangru0908@bupteducn The Authors, publshed by EDP Scences Ths s an open access artcle dstrbuted under the terms of the Creatve Commons Attrbuton Lcense 0 (http://creatvecommonsorg/lcenses/by/0/)
Fgure 1 Schematc dagram of the robot The parameters of the robot D-H can be obtaned as table 1: Table 1 Robot DH parameter table 1 a [m] 1 [ ] d [mm] [ ] 1 0 0 0 1 2 l2 90 0 2 3 l 3 0 0 3 l 90 d 5 0 90 0 5 6 0 90 d 6 6 The poston and atttude of the end of manpulator can be obtaned through the robot coordnate system: nx ox ax px ny oy ay p y T = (1) n z o z a z p z 0 0 0 1 nx ox ax Where: ny oy a y s the rotaton matrx (atttude) of the robot end coordnate system wth nz oz a z respect to base coordnate system; Formula (2) s the center of end poston for robot c cos, s sn, cj cos( j ), sj sn( j ) px l2c1dcs 1 23lcc 1 23ds1l3cc 1 2 p y = l2s1 dss 1 23 dc1 lsc 1 23 l3c2s 1 p z ls23dc23l3s 2 (2) 2
3 Implementaton of AutoCAD plug-n n the workspace of robot Because of the smplcty of Vsual LISP language syntax, the user can drectly call the AutoCAD to draw through commends, and debug and check easly Other languages wll ncrease the complexty of development Therefore, Vsual LISP s used to calculate the software development In AutoCAD development envronment wth Vsual Lsp, usng Auto Lsp language fle "*lsp" s wrtten to realze smulaton of the robot workspace program The user dalog nterface fle "*dcl" format s generated, whch s achevng the loadng and dsplay Add a custom menu "Industral Robot" to AutoCAD menu bar Then load the "*lsp" source code fles and "*dcl" dalog box fle through the custom command macro After the user clcks "OK" button, t gets the edt box and checks the nput data And then, t completes the follow-up program on the drawng commands of the workspace part at the tme of closng the dalog box Ultmately, two development of the software nterface n AutoCAD s shown n Fgure 2 Fgure 2 Robot workspace dalog box By the Formula (2), we can calculate the 2D workspace of the robot n whch end reference pont s formed on the base coordnate system Combned wth the scope of the angle and the ntal value of length parameters, the secton of workspace n the YOZ drecton can be gotten when =90 1 See the use of Auto LISP programmng n Fgure 3 On the bass of 2D workspace, changng 1 from the mnmum value gradually ncreased to the maxmum value, the 3D workspace of the robot wth sx degrees of freedom can be obtaned 3
Fgure 3 2D space dagram wth the sold boundary range The nfluence of structural parameters on the workspace of the robot The workspace of the robot s drawn by the software wrtten by LISP Vsual to understand the nfluence of the change of the structure parameters on the workspace The man varables are the length varable l 2 l 3 d, and angle varable 2 3 Because of the small mpact of l, t s not consdered The orgnal mage and the pcture after changng the mechansm parameters wll be put together for the convenence of comparson 1 The nfluence of the changng rod length on workspace The boundary map of the workspace s obtaned by settng value of l 2 n turn as shown n Fgure Analyss shows that, when other parameters are kept constant, only ncreasng or decreasng the l 2, the sze and shape of the YOZ workng plane reman unchanged, that s to say only changng the poston of the workspace When the ncrease l 2, the YOZ workng plane has a tendency to move upward; otherwse, t s downward 120mm 320mm 520mm 720mm 92mm Fgure YOZ plane change trend chart when changng l 2 Fgure 5 s the boundary map of the workspace when l 3 s changed The analyss shows that when other parameters reman unchanged and ncrease l 3, the YOZ workng plane has a tendency to move
upward, meanwhle, the area ncreases; otherwse the opposte Fgure 6 s the boundary map when d s changed We can know that when other parameters reman unchanged, only ncrease the d, the robot YOZ workng plane area ncreased, otherwse decreased 575mm 775mm 975mm 1175mm 1375mm 78mm 687mm 887mm 1087mm 1287mm Fgure 5 YOZ plane change trend chart when changng l 3 Fgure 6 YOZ plane change trend chart when changng d 2 The Influence of the Changng Angle Range on the Workspace As shown n Fgure 7, the boundary map of workspace s obtaned after the change of scope of 2 Analyss shows that when other parameters are kept constant and only the angel range of 2 s ncreased, the YOZ workng plane of the robot s expanded gradually and the area ncreases, otherwse t wll decrease Fgure 8 s obtaned from changng of 3 Analyss shows that, when other parameters reman unchanged, the YOZ workng plane area of the robot s ncreased wth the ncrease of the angle; otherwse t wll decrease And when the angle range ncreases to a certan degree, the YOZ workng plane nteror wll change from the depresson nto the bulge Ths stuaton should be pad attenton to when desgnng -35 ~110-50 ~125-65 ~10-80 ~155-95 ~170 Fgure 7 YOZ plane change trend chart when changng 2-150 ~0-165 ~55-180 ~70-180 ~100 Fgure 8 YOZ plane change trend chart when changng 3 5
5 Concluson Through secondary development on AutoCAD platform, the workspace of sx degrees of freedom ndustral robot s studed Accordng to the modfed DH parameter, the modelng of the robot s carred out Usng Vsual LISP the dalog nterface program s wrtten to smulate the workspace of the robot By changng the nput parameters, the workspace can be quckly and accurately drawn and the range of moton of the robot can be calculated So the nfluence of structural parameters on the workspace can be analyzed drectly Ths s a clear, smple and effectve method to determne the workspace of ndustral robot The method can quckly determne the structure sze and the range of moton of the robot accordng to the desgn requrements of the work, so as to mprove the workng effcency At the same tme, t also creates a good basc condton for the robot dynamcs analyss, trajectory plannng and moton control References 1 Z Dong, C Yn, X L Research on characterstcs and movement space of palletzng robot mechancal arm[j] Journal of Chnese Agrcultural Mechanzaton, 35(6), 53-56, 6 (201) 2 J Behnoush Rezaean, O Kambz Ghaem, M Al Optmzaton of knematc redundancy and workspace analyss of a dual-arm cam-lock robot[j] Robotca, 3, 23-2 (2016) 3 L Jnquan, Duan bngle, L Zhongmng, etal Analyss on Workspace and Influence Coeffcent of a Proposed Palletzng Robot[J] Journal of Bejng Unversty of Posts and Telecommuncatons, 3(6), 78-81 (2011) W F Xu, L T L, B Lang, et al Workspace analyss of space 3R robot[j] Journal of Astronautcs, 28(5), 1389-139 (2007) 5 Z Xe, C L, W N, etal Workspace analyss of a 6-DOF nstallng-calbratng robot[j] Advanced Materals Research, 22, 75-78 (2012) 6 Z Lu, H Lu, Z Luo, etal Improvement on Monte Carlo method for robot workspace determnaton[j] Transactons of the Chnese Socety for Agrcultural Machnery,, 230-235 (2013) 7 P Adrán, GArturo, MJosé María Monte-Carlo workspace calculaton of a Seral-Parallel bped robot[j] Advances n Intellgent Systems and Computng, 18, 157-169 (2016) 8 Y Hou, C Wang, X Hu, etal A New Method for Workspace Boundary Extracton for Jonted Seral Robot[J] Chna Mechancal Engneerng, 26(3), 308-312, 318 (2015) 9 Tan Habo, Ma Hongwe, WeJuan, etal Workspace and Structural Parameters Analyss for Manpulator of Seral Robot[J] Transactons of The Chnese Socety of Agrcultural Machnery, (), 196-200 (2013) 10 J Y, Y Dng System of Robot Dynamcs Smulaton Based on AutoLISP[J] Coal Technology, 32(5), 158-160 (2013) 6