Knowledge

Chebyshev linkage

Source 📝

68: 20: 662: 977: 954: 877: 436: 361: 795: 731: 425: 279: 215: 883: 811: 130:
The motion of the linkage can be constrained to an input angle that may be changed through velocities, forces, etc. The input angles can be either link 
657:{\displaystyle \varphi _{2}=\arcsin \left-\arccos \left({\frac {L_{4}^{2}+{\overline {AO_{2}}}^{2}-L_{3}^{2}}{2\,L_{4}\,{\overline {AO_{2}}}}}\right)\,} 968:. In this application the approximate straight movement is translated away from the line's midpoint, but it is still essentially the same mechanism. 1046: 1088: 106:. One of the problems was the construction of a linkage that converts a rotary motion into an approximate straight-line motion (a 1078: 667:
Consequently, we can write the motion of point P, using the two points defined above and the definition of the middle point.
290: 144:
with the horizontal. Regardless of the input angle, it is possible to compute the motion of two end-points for link 
737: 673: 367: 221: 157: 985: 1000: 107: 103: 1083: 1035: 67: 1043: 949:{\displaystyle \varphi _{\text{max}}=\arccos \left({\frac {-1}{5}}\right)\approx 101.537^{\circ }.\,} 872:{\displaystyle \varphi _{\text{min}}=\arccos \left({\frac {4}{5}}\right)\approx 36.8699^{\circ }.\,} 965: 964:
Chebyshev linkages did not receive widespread usage in steam engines, but are commonly used as the
119: 99: 88: 995: 84: 1050: 989: 1019: 1056: 1072: 92: 980:
Chebyshev's Lambda Mechanism (one blue and one green) shows an identical motion path
976: 115: 19: 1062: 111: 76: 430:
And ultimately, we will write the output angle in terms of the input angle,
284:
while the motion of point B will be computed with the other angle,
975: 66: 18: 886: 814: 740: 676: 439: 370: 356:{\displaystyle x_{B}=L_{1}-L_{4}\cos(\varphi _{2})\,} 293: 224: 160: 805:
The limits to the input angles, in both cases, are:
57:
Link 1 (horizontal distance between ground joints):
1038:"How to draw a straight line, by A.B. Kempe, B.A." 948: 871: 789: 725: 656: 419: 355: 273: 209: 98:It was invented by the 19th-century mathematician 151:that we will name A and B, and the middle point. 790:{\displaystyle y_{P}={\frac {y_{A}+y_{B}}{2}}\,} 726:{\displaystyle x_{P}={\frac {x_{A}+x_{B}}{2}}\,} 102:, who studied theoretical problems in kinematic 420:{\displaystyle y_{B}=L_{4}\sin(\varphi _{2})\,} 274:{\displaystyle y_{A}=L_{2}\sin(\varphi _{1})\,} 210:{\displaystyle x_{A}=L_{2}\cos(\varphi _{1})\,} 8: 966:'Horse head' design of level luffing crane 945: 936: 910: 891: 885: 868: 859: 838: 819: 813: 786: 774: 761: 754: 745: 739: 722: 710: 697: 690: 681: 675: 653: 634: 624: 623: 617: 612: 601: 596: 583: 571: 561: 551: 546: 539: 509: 490: 476: 470: 463: 444: 438: 416: 407: 388: 375: 369: 352: 343: 324: 311: 298: 292: 270: 261: 242: 229: 223: 206: 197: 178: 165: 159: 1012: 1053:using the Molecular Workbench software 7: 1022:– Cross link straight-line mechanism 23:Animation for the Chebyshev linkage. 14: 137:with the horizontal or link  16:Four-bar straight-line mechanism 496: 483: 413: 400: 349: 336: 267: 254: 203: 190: 1: 641: 578: 516: 110:). This was also studied by 114:in his improvements to the 1105: 71:Illustration of the limits 1059:simulation of the linkage 992:of the Chebyshev linkage. 1089:Straight line mechanisms 986:Chebyshev lambda linkage 25:Dimensions (unit length 1001:Straight line mechanism 108:straight line mechanism 49: Links 2 & 4: 981: 950: 873: 791: 727: 658: 421: 357: 275: 211: 72: 64: 1079:Linkages (mechanical) 979: 951: 874: 792: 728: 659: 422: 358: 276: 212: 70: 22: 1036:Cornell university, 884: 812: 738: 674: 437: 368: 291: 222: 158: 118:, which resulted in 606: 556: 126:Equations of motion 81:Chebyshev's linkage 1049:2011-07-25 at the 1020:Cornell university 982: 946: 869: 787: 723: 654: 592: 542: 417: 353: 271: 207: 73: 65: 923: 894: 846: 822: 784: 720: 647: 644: 581: 520: 519: 100:Pafnuty Chebyshev 89:rotational motion 1096: 1023: 1017: 996:Four-bar linkage 955: 953: 952: 947: 941: 940: 928: 924: 919: 911: 896: 895: 892: 878: 876: 875: 870: 864: 863: 851: 847: 839: 824: 823: 820: 796: 794: 793: 788: 785: 780: 779: 778: 766: 765: 755: 750: 749: 732: 730: 729: 724: 721: 716: 715: 714: 702: 701: 691: 686: 685: 663: 661: 660: 655: 652: 648: 646: 645: 640: 639: 638: 625: 622: 621: 607: 605: 600: 588: 587: 582: 577: 576: 575: 562: 555: 550: 540: 525: 521: 515: 514: 513: 500: 499: 495: 494: 475: 474: 464: 449: 448: 426: 424: 423: 418: 412: 411: 393: 392: 380: 379: 362: 360: 359: 354: 348: 347: 329: 328: 316: 315: 303: 302: 280: 278: 277: 272: 266: 265: 247: 246: 234: 233: 216: 214: 213: 208: 202: 201: 183: 182: 170: 169: 85:four-bar linkage 63: 55: 48: 43: 33: 28: 1104: 1103: 1099: 1098: 1097: 1095: 1094: 1093: 1069: 1068: 1051:Wayback Machine 1032: 1027: 1026: 1018: 1014: 1009: 974: 962: 932: 912: 906: 887: 882: 881: 855: 834: 815: 810: 809: 803: 770: 757: 756: 741: 736: 735: 706: 693: 692: 677: 672: 671: 630: 626: 613: 608: 567: 563: 560: 541: 535: 505: 501: 486: 466: 465: 459: 440: 435: 434: 403: 384: 371: 366: 365: 339: 320: 307: 294: 289: 288: 257: 238: 225: 220: 219: 193: 174: 161: 156: 155: 150: 143: 136: 128: 91:to approximate 58: 56: 50: 46: 44: 35: 31: 26: 24: 17: 12: 11: 5: 1102: 1100: 1092: 1091: 1086: 1081: 1071: 1070: 1067: 1066: 1065:of the linkage 1060: 1054: 1041: 1031: 1030:External links 1028: 1025: 1024: 1011: 1010: 1008: 1005: 1004: 1003: 998: 993: 973: 970: 961: 958: 957: 956: 944: 939: 935: 931: 927: 922: 918: 915: 909: 905: 902: 899: 890: 879: 867: 862: 858: 854: 850: 845: 842: 837: 833: 830: 827: 818: 802: 799: 798: 797: 783: 777: 773: 769: 764: 760: 753: 748: 744: 733: 719: 713: 709: 705: 700: 696: 689: 684: 680: 665: 664: 651: 643: 637: 633: 629: 620: 616: 611: 604: 599: 595: 591: 586: 580: 574: 570: 566: 559: 554: 549: 545: 538: 534: 531: 528: 524: 518: 512: 508: 504: 498: 493: 489: 485: 482: 479: 473: 469: 462: 458: 455: 452: 447: 443: 428: 427: 415: 410: 406: 402: 399: 396: 391: 387: 383: 378: 374: 363: 351: 346: 342: 338: 335: 332: 327: 323: 319: 314: 310: 306: 301: 297: 282: 281: 269: 264: 260: 256: 253: 250: 245: 241: 237: 232: 228: 217: 205: 200: 196: 192: 189: 186: 181: 177: 173: 168: 164: 148: 141: 134: 127: 124: 120:Watt's linkage 87:that converts 45: 34: Link 3: 30: 15: 13: 10: 9: 6: 4: 3: 2: 1101: 1090: 1087: 1085: 1084:Linear motion 1082: 1080: 1077: 1076: 1074: 1064: 1061: 1058: 1055: 1052: 1048: 1045: 1042: 1040: 1039: 1034: 1033: 1029: 1021: 1016: 1013: 1006: 1002: 999: 997: 994: 991: 987: 984: 983: 978: 971: 969: 967: 959: 942: 937: 933: 929: 925: 920: 916: 913: 907: 903: 900: 897: 888: 880: 865: 860: 856: 852: 848: 843: 840: 835: 831: 828: 825: 816: 808: 807: 806: 800: 781: 775: 771: 767: 762: 758: 751: 746: 742: 734: 717: 711: 707: 703: 698: 694: 687: 682: 678: 670: 669: 668: 649: 635: 631: 627: 618: 614: 609: 602: 597: 593: 589: 584: 572: 568: 564: 557: 552: 547: 543: 536: 532: 529: 526: 522: 510: 506: 502: 491: 487: 480: 477: 471: 467: 460: 456: 453: 450: 445: 441: 433: 432: 431: 408: 404: 397: 394: 389: 385: 381: 376: 372: 364: 344: 340: 333: 330: 325: 321: 317: 312: 308: 304: 299: 295: 287: 286: 285: 262: 258: 251: 248: 243: 239: 235: 230: 226: 218: 198: 194: 187: 184: 179: 175: 171: 166: 162: 154: 153: 152: 147: 140: 133: 125: 123: 121: 117: 113: 109: 105: 101: 96: 94: 93:linear motion 90: 86: 82: 78: 69: 62: 54: 42: 38: 21: 1044:A simulation 1037: 1015: 963: 804: 801:Input angles 666: 429: 283: 145: 138: 131: 129: 116:steam engine 97: 80: 74: 60: 52: 40: 36: 1073:Categories 1063:A 3D video 1057:A Geogebra 1007:References 112:James Watt 104:mechanisms 77:kinematics 938:∘ 930:≈ 914:− 904:⁡ 889:φ 861:∘ 853:≈ 832:⁡ 817:φ 642:¯ 590:− 579:¯ 533:⁡ 527:− 517:¯ 488:φ 481:⁡ 457:⁡ 442:φ 405:φ 398:⁡ 341:φ 334:⁡ 318:− 259:φ 252:⁡ 195:φ 188:⁡ 1047:Archived 972:See also 990:cognate 934:101.537 857:36.8699 988:, the 901:arccos 829:arccos 530:arccos 454:arcsin 47:  32:  960:Usage 83:is a 893:max 821:min 478:sin 395:sin 331:cos 249:sin 185:cos 75:In 29:): 1075:: 122:. 95:. 79:, 39:+ 943:. 926:) 921:5 917:1 908:( 898:= 866:. 849:) 844:5 841:4 836:( 826:= 782:2 776:B 772:y 768:+ 763:A 759:y 752:= 747:P 743:y 718:2 712:B 708:x 704:+ 699:A 695:x 688:= 683:P 679:x 650:) 636:2 632:O 628:A 619:4 615:L 610:2 603:2 598:3 594:L 585:2 573:2 569:O 565:A 558:+ 553:2 548:4 544:L 537:( 523:] 511:2 507:O 503:A 497:) 492:1 484:( 472:2 468:L 461:[ 451:= 446:2 414:) 409:2 401:( 390:4 386:L 382:= 377:B 373:y 350:) 345:2 337:( 326:4 322:L 313:1 309:L 305:= 300:B 296:x 268:) 263:1 255:( 244:2 240:L 236:= 231:A 227:y 204:) 199:1 191:( 180:2 176:L 172:= 167:A 163:x 149:3 146:L 142:4 139:L 135:2 132:L 61:a 59:4 53:a 51:5 41:a 37:a 27:a

Index



kinematics
four-bar linkage
rotational motion
linear motion
Pafnuty Chebyshev
mechanisms
straight line mechanism
James Watt
steam engine
Watt's linkage
'Horse head' design of level luffing crane

Chebyshev lambda linkage
cognate
Four-bar linkage
Straight line mechanism
Cornell university
Cornell university, "How to draw a straight line, by A.B. Kempe, B.A."
A simulation
Archived
Wayback Machine
A Geogebra
A 3D video
Categories
Linkages (mechanical)
Linear motion
Straight line mechanisms

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.