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# BUILDING A ROBOT ARM

Figure (robot): The RMIT Robot Arm

The model shown in Figure (robot) will be described in a step by step instructions on how to build and display this model.

This is the MGED input file:

    in btm	box	0 0 0    0 -90 0      40 0 0   0 0 6
    in btm1	box	0 -90 0  0 -61.549 0  40 0 0   0 0 6
    in rad	rcc	20 -150 0   0 0 6   8
    in cyl	rcc	20 -45 6    0 0 30  20
    in cyl1 rcc	20 -45 0 0 0 36 15.5
    in cyl2 rcc	20 -45 0 0 0 36 12.5
    in hole rcc	8 -8 0   0 0 6   3
    in hole1 rcc	32 -8 0  0 0 6   3
    cp hole1 hole2
    in gus	raw	21.5 -25.3 6  0 0 30  0 25.3 0  -3 0 0
    in cnr	box	0 0 0	6 6 0	6 0 0	0 0 6
    in cnr1	box	34 0 0	0 -6 0	6 0 0	0 0 6
    cp cnr cnr2
    cp cnr1 cnr3
    in rad1 rcc	6 -6 0	0 0 6 6
    in rad2 rcc	34 -6 0	0 0 6 6
    in head rcc	20 -45 36 0 0 30 18
    in shaft rcc	20 -45 36 0 0 -50 12.5
    in han	rcc	20 -45 51 0 120 0 6
    in ball sph	20 75 51  15
    in cut box	20 -45 0	0 50 0	25 0 0	0 0 40
    in squ box	12 -53 -14  	0 16 0   16 0 0   0 0 -30
    r handle u squ u shaft u han - ball
    r knob u ball
    r cor u cnr2 + rad1
    r cor1 u cnr3 + rad2
    in hole4 rcc 20 -150 0   0 0 6   3
    cp hole2 hole3
    r base u btm u btm1 - hole2 - hole3 - hole4 u rad - hole4
    g all base handle knob
    size 300
    e all

This is the MGED dialog:

    mged mark
    BRL Graphics Editor (MGED) Version 2.31
      Sat Oct 17 20:33:05 PDT 1987
      mg\@godzilla:/usr/staff/mg/brlcad/mged

    mark: No such file or directory
    Crete new database (y/n)[n]? y
    attach (nu|tek|plot|ir) [nu]? nu
    ATTACHING nu (Null Display)
    Untitled MGED Database (units=mm)
    mged> in btm box 0 0 0 0 -90 0 40 0 0 0 0 6
    mged> in btm1 box
    Enter X, Y, Z of vertex:  0 -90 0
    Enter X, Y, Z of vector H:  0 -61.549 0
    Enter X, Y, Z of vector W:  50 0 0   40 0 0
    Enter X, Y, Z of vector D: 0 0 6
    mged> in rad rcc 20 -150 0 0 0 6 8
    mged> in cyl rcc
    Enter X, Y, Z of vertex:  20 -45 6
    Enter X, Y, Z of height (H) vector: 0 0 30
    Enter radius:  20
    mged> in cyl1 rcc 20 -45 0 0 0 36 15.5
    mged> in cyl2 rcc 20 -45 0 0 0 36 12.5
    mged> in hole rcc 8 -8 0 0 0 6 3
    mged> in hl ole 1 rcc 2 32 -8 0 0 0 6 2 3
    mged> cp hole1 hole2
    mged> in gus raw
    Enter X, Y, Z of vertex: 21.5 -25.3 6
    Enter X, Y, Z of vector H: 0 0 30
    Enter X, Y, Z of vector W: 0 25.3 6
    Enter X, Y, Z of vector D: -3 0 0
    mged> in cnr box 0 0 0 06 6 0 6 0 0 0 0 6
    mged> incnr1 box 34 0 0 0 -6 0 6 0 0 0 0 6
    incnr1: no such command, type ? for help
    mged> in cnr1 box 34 0 0 0 -6 0 6 0 0 0 0 6
    mged> cp cnf r cnr2
    mged> in cp cnr1 cnr3
    mged> in rad1 rcc 6 -6 0 0 0 6 6
    mged> in rad2 rcc 34 -6 0 0 0 6 6
    mged> in shaft rcc 20 -45 36 0 0 30 18
    mged> in shaft rcc 20 -45 36 0 0 -50 12.5
    mged> in han rcc 20 -45 51 0 120 0 6
    mged> in ball sph
    Enter X, Y, Z of vertex: 20 75 51
    Enter radius: 15
    mged> in cut box 20 -45 0 0 50 0 25 0 0 0 040
    Enter Z: 03  NOTE: error again
    mged> killall cut
    mged> in cut box 20 -45 0 0 50 0 25 0 0 0 0 40
    mged> in squ box 12 -53 -14 0 16 0 16 0 0 0 0- -30
    mged> r handle + squ shaft u han u ball
    Defaulting item number to 1001
    Creating region id=1000, air=0, los=100, GIFT material=1
    mged> r knob + ball
    Defaulting item number to 1002
    Creating region id=1001, air=0, los=100, GIFT material=1
    mged> r cor + cnr2 + rad1
    Defaulting item number to 1003
    Creating region id=1002, air=0, los=100, GIFT material=1
    mged> r cor1 + cnr3 + rad2
    Defaulting item number to 1004
    Creating region id=1003, air=0, los=100, GIFT material=1
    mged> mater knob plastic
    Was
    Parameter string? n
    Override material color (y/n)[n]? y
    R G B (0..255)? 255 0 0  NOTE:  This is color RED
    mged> mater handle plastic
    mged> Was
    Parameter string? n
    Override material color (y/n)[n]? y
    R G B (0..255)? 219 147 112   NOTE:  This is color TAN
    mged> r base + btm u btm1 u gus cyl - cyl1 m1 - hole2 -hole3 -hole4 u rad-
    hole4
    mged> error in number of args!   NOTE: Typing errors
    mged> r base + btm u btm1 - hole2 - hole3 - hole4 u rad - hole4
    Defaulting item number to 1005
    Creating region id=1004, air=0, los=100, GIFTmaterial=1
    dir_lookup:  could not find "hole3"
    skipping hole3
    dir_lookup:  could not find "hole4"
    skipping hole4
    dir_lookup:  could not find "hole4"
    skipping hole4
    mged> t
    ball     cnr3     gus     knob/
    base/     cor/     han     rad
    btm     cor1/     handle     rad1
    btm1     cut     head     rad2
    cnr     cyl     hole     shaft
    cnr1     cyl1     hole1     squ
    cnr2     cyl2     hole2
    mged> in hole 4 rcc 20 -150 0 0 0 6 3
    mged> cp hole2 hole3
    mged> killall base NOTE:  Redo "base" region
    mged> r base + btm u btm1 - hole2 - hole3 - hole4 u rad - hole4
    Defaulting item number to 1006
    Creating region id=1005, air=0, los=100, GIFTmaterial=1
    mged> g all base handle knob
    mged> tree all
    | all_________________| base_________| btm
                             | btm1
                             | hole2
                             | hole 3
                             | hole4
                             | rad
                             | hole4
                             | handle______________| squ
                                         | shaft
                                         | han
                                         | ball
                             | knob________________| ball
                | handle_______________| squ
                            | shaft
                            | han
                            | ball
                | knob_________________| ball
    mged> l base
    base (len 9) REGION id=1005 (air=0, los=100, GIFTmater=1)--
     + btm
     u btm1
     - hole2
     - hole3
     - hole4
     u rad
     - hole4
     u handle
     u knob
    mged> l gus
    gus:  ARB8 (ARB6)
    1 (21.5000, -25.3000, 6.0000)
    2 (21.5000, 0.0000, 6.0000)
    3 (21.5000, 0.0000, 6.0000)
    4 (21.5000, -25.3000, 36.0000)
    5 (18.5000, -25.3000, 6.0000)
    6 (18.5000, 0.0000, 6.0000)
    7 (18.5000, 0.0000, 6.0000)
    8 (18.5000, -25.3000, 36.0000)
    mged> l ball
    ball:  ELL
    V (20.0000, 75.0000, 51.0000)
    A (15.0000, 0.0000, 0.0000) Mag=15.000000
    A dir cos=(0.0, 90.0, 90.0), rot=0.0, fb=0.0
    B (0.0000, 15.0000, 0.0000) Mag=15.000000
    B dir cos=(90.0, 0.0, 90.0) rot=90.0, fb=0.0
    C (0.0000, 0.0000, 15.0000) Mag=15.000000
    C dir cos=(90.0, 90.0, 0.0) rot=90.0, fb=90.0
    mged> l knob
    knob (len 1) REGION id=1001 (air=0, los=100, GIFTmater=1)--
    Material "plastic"
    Color 255 0 0
     + ball
    mged> l handle
    handle (len 4) REGION id=1000 (air=0, los=100, GIFT MATER=1)--
    Material "plastic" "n
    Color 219 147 112
     + squ
     u shaft
     u han
     u ball
    mged> canter-0-75 0
    mged> size 300
    mged> tops
    all/     cor1/     cyl2      hole1
    cnr      cut     gus
    cnr1     cyl     head
    cor/     cyl1     hole
    mged> analyze cyl
    cyl:  TGC
    V (20.0000, -45.0000, 6.0000)
    H (0.0000, 0.0000, 30.0000) Mag=30.000000
    H dir cos=(90.0, 90.0, 0.0), rot=90.0, fb=90.0
    A (-17.5032, -9.6767, 0.0000) Mag=20.000000
    B (9.6767,-17.5032, 0.0000) Mag=20.000002
    c=20.000000, d=20.000002
    AxB dir cos=(90.0, 90.0, 0.0), rot=90.0,fb=90.0
    Surface Areas:  base(AxB)=1256.6371
      top(CxD)=1256.6371 side=3769.9114
    Total Surface Area=6283.1855
       Volume=37699.1132 (0.0100 gal)
    mged> q