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  • 1Movie SegmentLocomotion Gates with Polypod, Mark Yim, Stanford University, ICRA 1994 video proceedings

    InstantaneousKinematics

    Linear & Angular Motion Velocity Propagation

    J a c o b i a n Differential Motion

    Explicit Form Static Forces

    Differential Motion

    {0}

    {n}{n}

    Forward Kinematics

    Instantaneous Kinematicsx x + +x

    Relationship: x x Linear VelocityAngular Velocity

    i i i i iq d = +

    Joint Coordinates

    i

    i

    revolute:

    d prismaticcoordinate i

    Joint coordinate-i:

    0 revolute1 prismatici

    = with

    1i i = andJoint Coordinate Vector: 1 2( .... )

    Tnq q q q=

  • 2Jacobians: Direct Differentiation

    ( );x f q=xx

    x

    f qf q

    f qm m

    1

    2

    1

    2

    # #

    F

    H

    GGGG

    I

    K

    JJJJ=F

    H

    GGGG

    I

    K

    JJJJ

    ( )( )

    ( )

    x fq

    q fq

    q

    x fq

    q fq

    q

    nn

    mm m

    nn

    11

    11

    1

    11

    = + +

    = + +

    "

    #"

    xfq

    fq

    fq

    fq

    qn

    m m

    n

    =

    L

    N

    MMMMM

    O

    Q

    PPPPP

    1

    1

    1

    1

    "# # #"

    .

    ( 1) ( ) ( 1)( )m m n nx J q q =

    Jacobian

    ( 1) ( ) ( 1)( )m m n nx J q q = where

    ( ) ( )ij ij

    J q f qq=

    ( 1) ( ) ( 1)( )m m n nx J q q =

    ( )x J =

    Example

    l1

    l2 (x,y) x l c l cy l s l s

    = += +

    1 1 2 12

    1 1 2 12

    x l s l s l sy l c l c l c

    = + = + +

    ( )( )

    1 1 2 12 1 2 12 2

    1 1 2 12 1 2 12 2

    X

    xy

    y l sx l c

    = LNMOQP =

    LNM

    OQPFHGIKJ

    2 12

    2 12

    1

    2

    J

    x x

    y yF

    H

    GGG

    I

    K

    JJJ

    1 2

    1 2

    ( )x J = 2 12

    2 12

    y l sx l c

    =

    Stanford Scheinman Arm

    d2d3

    x0

    z0y0

    1{0}

    2

    x6 y6z6

    4 5

    6

    i i-1 ai-1 di i1 0 0 0 12 -90 0 d2 23 90 0 d3 04 0 0 0 45 -90 0 0 56 90 0 0 6

    d2d3

    x0

    z0y0

    1{0}

    2

    x6 y6z6

    4 5

    6

    C C C C S S C S S S S S C S C CS C C C S S C S S S C

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    1 2 4 5 6 4 6 2 5 6 1

    [ ( ) ] ( )[ ( ) ]

    + + + + + + ( )

    ( ) +

    + +S C S C C

    S C C S S C C S S4 5 6 4 6

    2 4 5 6 4 6 2 5 6

    C C C C C S S S S C S S C C C SS C C C C S S S S C C S C C C S

    S C C C S S C S C

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    2 4 5 6 4 6 2 5 6

    [ ( ) ] ( )[ ( ) ] ( )

    ( )

    + + +

    ( )( )

    + + +

    +

    C C C S S C S S SS C C S S C C S S

    S C S C C

    1 2 4 5 2 5 1 4 5

    1 2 4 5 2 5 1 4 5

    2 4 5 2 5

    +

    C S d S dS S d C d

    C d

    1 2 3 1 2

    1 2 3 1 2

    2 3

    1

    2

    3

    Pxr

    x rr

    = =

  • 3Stanford Scheinman Arm

    xc s d s ds s d c d

    c dp =

    +

    L

    NMMM

    O

    QPPP

    1 2 3 1 2

    1 2 3 1 2

    2 3

    qqqqqq

    O

    QPPP

    L

    N

    MMMMMMM

    O

    Q

    PPPPPPP

    1

    2

    3

    4

    5

    6

    (3 1) (3 6) (6 1)( )pp x xx J q q =

    xyz

    F

    HGGI

    KJJ =L

    NMMM

    y c c d c sx s c d s s

    s d c

    L

    N

    1 2 3 1 2

    1 2 3 1 2

    2 3 2

    0 0 00 0 0

    0 0 0 0

    Linear Velocity VLinear Velocity V

    x p =

    Position xr qr qr q

    R =L

    NMMM

    O

    QPPP

    1

    2

    3

    ( )( )( )

    (( )

    (

    xrrr

    rq

    rq

    rq

    rq

    rq

    rq

    qq

    q

    R

    x

    x

    x

    =F

    HGGI

    KJJ =

    F

    H

    GGGGGG

    I

    K

    JJJJJJ

    F

    H

    GGGG

    I

    K

    JJJJ

    1

    2

    3 9 1)

    1

    1

    1

    6

    2

    1

    2

    6

    3

    1

    3

    6 9 6

    1

    2

    6 6 1)

    "

    "

    "#

    ( ) x J q qR XR=Orientation: Direction Cosines

    C C C C S S C S S S S S C S C CS C C C S S C S S S C

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    1 2 4 5 6 4 6 2 5 6 1

    [ ( ) ] ( )[ ( ) ]

    + + + + + + ( )

    ( ) +

    + +S C S C C

    S C C S S C C S S4 5 6 4 6

    2 4 5 6 4 6 2 5 6

    C C C C C S S S S C S S C C C SS C C C C S S S S C C S C C C S

    S C C C S S C S C

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    2 4 5 6 4 6 2 5 6

    [ ( ) ] ( )[ ( ) ] ( )

    ( )

    + + +

    ( )( )

    + + +

    +

    C C C S S C S S SS C C S S C C S S

    S C S C C

    1 2 4 5 2 5 1 4 5

    1 2 4 5 2 5 1 4 5

    2 4 5 2 5

    Rx =

    (( )

    (

    xrrr

    rq

    rq

    rq

    rq

    rq

    rq

    qq

    q

    R

    x

    x

    x

    =F

    HGGI

    KJJ =

    F

    H

    GGGGGG

    I

    K

    JJJJJJ

    F

    H

    GGGG

    I

    K

    JJJJ

    1

    2

    3 9 1)

    1

    1

    1

    6

    2

    1

    2

    6

    3

    1

    3

    6 9 6

    1

    2

    6 6 1)

    "

    "

    "#

    Representations

    XxxP

    R= LNMOQP

    CartesianSphericalCylindrical.

    Euler AnglesDirection CosinesEuler Parameters

    Jacobian for X ( ) ( ) x J q q

    x J q qP X

    R X

    P

    R

    ==

    ( )( )x

    xJ qJ q q

    P

    R

    X

    X

    P

    R

    FHGIKJ =FHGIKJ

    ( ) (12 (12 ) (X J q qx X x x1) 6 6 1)=The Jacobian is dependent on the representation

    Cartesian & Direction Cosines

    Basic Jacobian

    x E x vx E xP P P

    R R R ==

    ( ) ( )

    F IxH K (6 1)

    vJ q qxn nxG J = ( ) (( ) 0 6 1)

    {0}angular velocity

    linear velocity

    v

  • 4Examples

    x E x

    s cs

    c cs

    c sss

    cs

    xxyz

    E x

    R R R

    P P P

    =F

    HGGI

    KJJ =

    F

    H

    GGGG

    I

    K

    JJJJ

    =F

    HGGI

    KJJ =

    F

    HGG

    I

    KJJ

    ; ( )

    . .

    ; ( )

    1

    00

    1 0 00 1 00 0 1

    *

    *

    Jacobian for X

    ( )xx J q q=

    0( ) ( ) ( )xJ q E x J q=

    P

    R

    xx

    x = Given a representation

    0 ( )v

    J q qw

    = Basic Jacobian

    Jacobian and Basic Jacobianv

    J q q

    v JJ

    q

    v J qJ q

    v

    v

    FHGIKJ =FHGIKJ =FHGIKJ

    ==RST

    0 ( ).

    .

    . .

    . ( . ) . ( . ) x E v x E J qx E x E J qP P P P v

    R R R R

    = == = J E JJ E J

    X P v

    X R

    P

    R

    ==

    RST..

    00P vXP

    RXR w

    E JJJEJ J

    = =

    0( ) ( ) ( )J q E X J q=

    0 ( )v

    J q qw

    =

    With Cartesian Coordinates

    3 ; ;P XP vE I J J= = and 00 RI

    EE

    =

    Position Representations

    3( )PE X I=Cartesian Coordinates ( , , )x y z

    cos sin 0

    ( ) sin cos 0

    0 0 1

    PE X

    =

    Cylindrical Coordinates ( , , )z Using ( ) ( cos sin )T Tx y z z =

    ( ) ( )cos sin sin sin cos

    ( ) sin cos 0sin sincos cos sin cos sin

    PE X

    =

    Spherical Coordinates ( , , )

    ( ) ( cos sin sin sin cos )T Tx y z =Using

  • 5Euler Angles

    Singularity of the representationfor k =

    . . 1

    ; ( ) 0

    0

    R R R

    s c c cs s

    x E x c ss cs s

    = =

    Jacobian for X

    ( )xx J q q=

    0( ) ( ) ( )xJ q E x J q=

    P

    R

    xx

    x = Given a representation

    0 ( )v

    J q qw

    = Basic Jacobian

    Jacobian

    vJ q q

    xxn nx

    FHGIKJ =( ( ) (( )

    6 1)

    6 1)

    {0}angular velocity

    linear velocity

    v

    Linear & Angular Velocities

    {0}angular velocity

    linear velocity

    v

    Linear VelocityvP A/

    P{A}

    {B}

    {C}

    vP A/A

    vP A/C

    vP A/BPure Translation

    {B}

    vP A/{A}

    vA B/

  • 6vP B/

    {B}

    vP A/{A}

    vA B/

    v v vP B A B P A/ / /= +

    Pure Translation Rotational Motion

    rigid bodyfixed points on the rigid bodyAxis of rotation

    Angular VelocityRotational Motion

    Angular Velocity

    vR

    Rotational Motion

    P

    Angular Velocity

    PvP

    vR

    ?Pv =

    Rotational Motion

    Angular Velocity

    PvP

    fixed point

    vR

    Rotational Motion

  • 7 Angular Velocity

    PvP

    P

    fixed point

    vR

    Rotational Motion

    Angular Velocity

    PsinP

    vP

    Pfixed point

    vR

    vP is proportional to: |||| ||Psin||

    and vP _| vP _| P

    v PP =

    Rotational Motion

    c a b= Cross Product Operator

    0 0

    0

    z y x

    z x y

    y x z

    a a bc ab a a b

    a a b

    = = c ab=

    : a skew-symmetric matrixa a vectors matrices

    ,x x

    y y

    z z

    a ba a b b

    a b

    = =

    c ab = v P v PP P= = Cross Product Operator

    =L

    NMMM

    O

    QPPP

    x

    y

    z

    ;PPPP

    x

    y

    z

    =L

    NMMM

    O

    QPPP

    v PPPP

    P

    z y

    z x

    y x

    x

    y

    z

    = =

    L

    NMMM

    O

    QPPP

    L

    NMMM

    O

    QPPP

    .

    00

    0v PP =

    : a skew-symmetric matrix

    Simultaneous linear and angular motion

    {A}

    {B}vB A/

    vP B/P

    AP A

    AB A B

    A BP B

    AB B

    A BBv v R v R P/ / /. .= + +

    v v v PP A B A P B B/ / /= + + Movie SegmentBeach Volleyball, Toshiba, ICRA 1999 video proceedings

  • 8Spatial Mechanisms{2}

    {0}

    {1}{n}

    v

    ( ). x J= x v : linear velocity : angular velocity

    Propagation of velocities

    {i} ivi

    vi+1i+1+1

    {i+1}zi

    Pi+1

    zi+1

    i i i

    i i iZ+ +

    + + +

    = +=

    1 1

    1 1 1

    .

    v v P d Zi i i i i i+ + + += + +1 1 1 1 .

    Velocity propagation

    Linear

    Angular

    ii i

    i ii

    ii

    ii i

    iiv R v P d Z

    ++

    ++ +

    ++= + +1 1 1 1 1 1 1.( ) .

    Velocity propagationJoint 1

    v1 and 1 in frame {1}Joint i+1

    ii i

    i ii i

    iiR Z

    ++

    ++

    ++= +1 1 1 1 1 1 . .

    nn n nv and

    0

    0

    0

    0

    00

    v RR

    vnn

    n

    n

    nn

    nn

    FHGIKJ =FHG

    IKJFHGIKJ.

    {n-1} {n} v

    Example

    1

    {0}

    1P1

    P2

    P3

    l1

    l2

    l3

    2

    3v v Pi i i i+ += + 1 1

    v

    v v P

    v v P

    P

    P P

    P P

    1

    2 1

    3 2

    0

    1 2

    2 3

    == + = +

    01 1

    01 = . Z

    01

    1

    1 1

    1 1

    1 1

    1 1 120

    0 00 0

    0 0 0 0 0v

    l cl s

    l sl cP = +

    L

    NMMM

    O

    QPPP

    L

    NMMM

    O

    QPPP

    =L

    NMMM

    O

    QPPP

    .

    .

    ..

    . .

    0 0 02

    033 2

    v v PP P= + 0

    1 1

    1 1 1 1 20

    33

    0

    0 1 01 0 00 0 0

    vl sl c PP =

    L

    NMMM

    O

    QPPP

    +L

    NMMM

    O

    QPPP

    +.

    . . .( ).

    =L

    NMMM

    O

    QPPP

    +L

    NMMM

    O

    QPPP

    +l sl c

    l sl c

    1 1

    1 1 1

    2 12

    2 12 1 2

    0 0

    .. .

    .. .( )

    03 1 2 3

    00 = + +( ). Z

    l cl s2 12

    2 12

    0

    .

    .L

    NMMM

    O

    QPPP

  • 901 1 2 12 2 12

    1 1 2 12 2 12

    1

    2

    3

    3

    00

    0 0 0v

    l s l s l sl c l c l cP =

    + +

    L

    NMMM

    O

    QPPP

    L

    NMMM

    O

    QPPP

    ( ).

    03

    1

    2

    3

    0 0 00 0 01 1 1

    =L

    NMMM

    O

    QPPP

    L

    NMMM

    O

    QPPP

    .

    vJ

    FHGIKJ =F

    HGGG

    I

    KJJJ

    .

    1

    2

    3

    vJ

    J Revolute Joint i i iZ q =

    i i iV Z q= Prismatic Joint

    jVi

    The Jacobian (EXPLICIT FORM)

    The Jacobian (EXPLICIT FORM)

    Revolute

    ijV

    Linear Vel: jVAngular Vel:

    jV

    i inP inP

    i inP i

    i

    Prismatic

    none

    Effector Linear Velocity

    Effector Angular Velocity1[ ( )]

    n

    i i i i ini

    v V P=

    = + =

    = i ii

    n

    1

    Effector

    i i iV Z q=

    i i iZ q =

    v

    The Jacobian (EXPLICIT FORM)

    Revolute

    ijV

    Linear Vel: jVAngular Vel:

    jV

    i inP inP

    i inP i

    i

    Prismatic

    none

    Effector Linear Velocity

    Effector Angular Velocity1[ ( )]

    n

    i i i i in ii

    v Z Z P q=

    = +

    1( )

    n

    i i ii

    Z q=

    =

    Effector

    i i iV Z q=

    i i iZ q =

    v

    1 1 1 1 1 1

    1 1 1 1 ( 1) 1

    [ ( )][ ( )]

    n

    n n n n n n n n n n

    v Z Z P qZ Z P q Z q

    = + ++ + +

    "

    [ ]1

    21 1 1 1 1 2 2 2 2 2( ) ( )n n

    n

    qq

    v Z Z P Z Z P

    q

    = + +

    " #

    vv J q= 1 1 1 2 2 2 n n nZ q Z q Z q = + + + "

    [ ]1

    21 1 2 2 n n

    n

    qq

    Z Z Z

    q

    =

    " #J q =

    The Jacobian

    vxyz

    xxq

    qxq

    qxq

    qPP P P

    nn=

    F

    HGGI

    KJJ = = + + +

    . . .

    1 1 2 2 "

    1 2

    P P Pv

    n

    x x xJq q q

    = "

    v

    w

    JJJ

    = Matrix (direct differentiation)vJ

  • 10

    Jacobian in a FrameVector Representation

    Jxq

    xq

    xq

    Z Z Z

    P P P

    n

    n n

    = FHGG

    IKJJ

    1 2

    1 1 2 2

    "". . .

    In {0}

    0

    0

    1

    0

    2

    0

    10

    1 20

    20

    Jxq

    xq

    xq

    Z Z Z

    P P P

    n

    n n

    =

    F

    HGG

    I

    KJJ

    "

    ". . .

    J in Frame {0}

    01

    0

    2

    0 0

    1 10

    2 20 0

    J qx

    qx

    qx

    R Z R Z R Z

    P Pn

    P

    n n

    =

    F

    HGG

    I

    KJJ

    ( ) ( ) ( )

    .( . ) .( . ) .( . )

    ""

    0iZ = 0 ;ii iR Z

    001

    iiZ Z

    = =

    Stanford Scheinman Arm

    J =F

    HGG

    I

    KJJ1 13

    Z P 2 23Z P 3Z2Z1Z 4Z 5Z 6Z

    0 0 0

    0

    Z6

    Z0 X6X0

    d3d2

    Y6Y0

    i i-1 ai-1 di i1 0 0 0 12 -90 0 d2 23 90 0 d3 04 0 0 0 45 -90 0 0 56 90 0 0 6

    Z6

    Z2

    Z3 Z4

    Z5Z1Z0

    X2

    X3 X4

    X5X6

    X0X1

    d3d2 d2 d3

    x0

    z0y0

    1{0}

    2

    x6 y6z6

    4 5

    6

    i i-1 ai-1 di i1 0 0 0 12 -90 0 d2 23 90 0 d3 04 0 0 0 45 -90 0 0 56 90 0 0 6

    T =i - 11

    ci -si 0 ai-1si ci-1 ci ci-1 -si-1 -s i-1 disi si-1 ci si-1 ci-1 ci-1 di

    0 0 0 1

    T = T T ... T0N0

    1

    1

    2

    N-1

    NForward Kinematics:

  • 11

    10

    1 1

    1 1

    0 00 0

    0 0 1 00 0 0 1

    T

    c ss c=

    L

    N

    MMMM

    O

    Q

    PPPP

    21

    2 2

    2

    2 2

    0 00 0 1

    0 00 0 0 1

    T

    c sd

    s c=

    L

    N

    MMMM

    O

    Q

    PPPP

    32 3

    1 0 0 00 0 10 1 0 00 0 0 1

    Td=

    L

    N

    MMMM

    O

    Q

    PPPP

    Stanford Scheinman Arm

    43

    4 4

    4 4

    0 00 0

    0 0 1 00 0 0 1

    T

    c ss c=

    L

    N

    MMMM

    O

    Q

    PPPP

    54

    5 5

    5 5

    0 00 0 1 0

    0 00 0 0 1

    T

    c s

    s c=

    L

    N

    MMMM

    O

    Q

    PPPP

    65

    6 6

    6 6

    0 00 0 1 0

    0 00 0 0 1

    T

    c s

    s c=

    L

    N

    MMMM

    O

    Q

    PPPP

    20

    1 2 1 2 1 1 2

    1 2 1 2 1 1 2

    2 2 0 00 0 0 1

    T

    c c c s s s ds c s s c c ds c

    =

    L

    N

    MMMM

    O

    Q

    PPPP

    30

    1 2 1 1 2 1 3 2 1 2

    1 2 1 1 2 1 3 2 1 2

    2 2 3 200 0 0 1

    T

    c c s c s c d s s ds c c s s s d s c ds c d c

    =

    +

    L

    N

    MMMM

    O

    Q

    PPPP

    10

    1 1

    1 1

    0 00 0

    0 0 1 00 0 0 1

    T

    c ss c=

    L

    N

    MMMM

    O

    Q

    PPPP

    1 2 4 1 4 1 2 4 1 4 1 2 1 3 2 1 2

    1 2 4 1 4 1 2 4 1 4 1 2 1 3 2 1 204

    2 4 2 4 2 3 2

    0 0 0 1

    c c c s s c c s s c c s c d s s ds c c c s s c s c c s s s d s c d

    Ts c s s c d c

    + + + =

    50

    1 2 4 1 4 1 3 2 1 2

    1 2 4 1 4 1 3 2 1 2

    2 4 3 2

    0 0 0 1

    T

    X X c c s s c c d s s dX X s c s c c s d s c dX X s s d c

    = + +

    L

    N

    MMMM

    O

    Q

    PPPP

    60

    1 2 4 5 1 4 5 1 2 5 1 3 2 1 2

    1 2 4 5 1 4 5 1 2 5 1 3 2 1 2

    2 4 5 5 2 3 2

    0 0 0 1

    T

    X X c c c s s s s c s s c d s s dX X s c c s c s s s s c s d s c dX X s c s c c d c

    = + + + +

    +

    L

    N

    MMMM

    O

    Q

    PPPP

    C C C C S S C S S S S S C S C CS C C C S S C S S S C

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    1 2 4 5 6 4 6 2 5 6 1

    [ ( ) ] ( )[ ( ) ]

    + + + + + + ( )

    ( ) +

    + +S C S C C

    S C C S S C C S S4 5 6 4 6

    2 4 5 6 4 6 2 5 6

    C C C C C S S S S C S S C C C SS C C C C S S S S C C S C C C S

    S C C C S S C S C

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    1 2 4 5 6 4 6 2 5 6 1 4 5 6 4 6

    2 4 5 6 4 6 2 5 6

    [ ( ) ] ( )[ ( ) ] ( )

    ( )

    + + +

    ( )( )

    + + +

    +

    C C C S S C S S SS C C S S C C S S

    S C S C C

    1 2 4 5 2 5 1 4 5

    1 2 4 5 2 5 1 4 5

    2 4 5 2 5

    +

    C S d S dS S d C d

    C d

    1 2 3 1 2

    1 2 3 1 2

    2 3

    1

    2

    3

    Pxr

    x rr

    = =

    60

    1 2 4 5 1 4 5 1 2 5 1 3 2 1 2

    1 2 4 5 1 4 5 1 2 5 1 3 2 1 2

    2 4 5 5 2 3 2

    0 0 0 1

    T

    X X ccc s ss s cs s cds sdX X sccs cs s ss c sds cdX X scs cc dc

    = + + + +

    +

    L

    N

    MMMM

    O

    Q

    PPPPZ6

    Z0 X6X0

    d3d2Y6

    Y00 0 0

    01 2 3

    0 0 0 0 01 2 4 5 6

    0 0 0

    0

    P P Px x xJ q q q

    Z Z Z Z Z

    = c d s s d c c d c ss d c s d s c d s s

    s d cs c s c c s s c c c c s s s s c s cc s s s c s c c s c c s c s s s s c

    c s s s c s c c

    +

    +

    + + + +

    L

    N

    MMMMMMM

    O

    Q

    P1 2 1 2 3 1 2 3 1 21 2 1 2 3 1 2 3 1 2

    2 3 2

    1 1 2 1 2 4 1 4 1 2 4 5 1 4 5 1 2 5

    1 1 2 1 2 4 1 4 1 2 4 5 1 4 5 1 2 5

    2 2 4 2 4 5 5 2

    0 0 00 0 0

    0 0 0 00 00 01 0 0

    PPPPPP

    Stanford Scheinman Arm Jacobian

  • 12

    Kinematic Singularity

    ( )1 2= " nJ J J J

    The Effector Locality loses the abilityto move in a direction or to rotate abouta direction - singular direction

    ( )det 0=J( ) ( )det det=i jJ J

    det[ ] det[ ]B AJ J

    Kinematic Singularity

    00

    BB AA

    BA

    RJ J

    R =

    ( ) ( )det det=i jJ J

    Singular Configurations

    det[ ( )] 0J q = Singular Configurations

    1 2det[ ( )] ( ) ( )... ( ) 0sJ q S q S q S q= =1

    2

    ( ) 0( ) 0

    ( ) 0s

    S qS q

    S q

    ==

    =#

    ( )1 2 21 2 2

    1 12 12

    1 12 12

    l S l S l SJ

    l C l C l C

    + = + ( ) 1 2det 2=J l l S

    Example (Kinematic Singularities)

    1 21 12= +x l C l C1 21 12= +y l S l S

    Singularity at 2 =q k

    l1

    l2

    1y

    {0}

    {1}

    2

    (x,y)

    At Singularity

    2 21

    1 2 2

    2 21 12 21 1

    l S l SC SJ

    l l C l CS C = +

    1 1 00J R J=

    1

    1 2 2

    0 0J

    l l l = +

    l1

    l2

    1y

    {0}

    {1}

    2

    (x,y)

    Example (Kinematic Singularities)

    1

    11 2 1 2 2

    0 x

    y l l l

    == + +( )

    L

    NMMM

    (x,y)

    1 2 11(1)

    1 2

    1 2 2 1

    1 1

    1

    l lJ

    l ll l l

    +

    small 2

    1 = q J X

    Small Displacements ,q X = x

    Xy

    1q1q

    {1} 2q 2q

  • 13

    (1) (1)1

    1 2 1

    1 = +x yql l( )1 2 (1) (1)

    21 2 2 1

    1+ = +l l x yql l l

    Small Displacements ,q X = x

    Xy

    1q1q

    {1} 2q 2q

    (1)

    1

    yl

    1q

    2(1)

    (1)

    xy

    (1)

    1

    yl

    2q

    21 2 (1)

    2 (1)

    ( )+ l l xl y

    1q1q

    {1} 2q 2q

    ( )1 2 21 2 2

    1 12 12

    1 12 12

    l S l S l SJ

    l C l C l C

    + = + ( ) 1 2det 2=J l l S

    Kinematic Singularities (reduced matrix)

    Singularity at 2 =q k

    l1

    l2

    1y

    {0}

    {1}

    2

    (x,y) ( )1 2 21 2 2

    1 12 12

    1 12 12

    0 00 01 1

    l S l S l S

    l C l C l CJ

    + + =

    l1

    l2

    l3

    E

    0

    1 1 2 12 3 123 2 12 3 123 3 123

    1 1 2 12 3 123 2 12 3 123 3 123

    0 0 00 0 00 0 01 1 1

    J

    l s l s l s l s l s l sl c l c l c l c l c l c

    E =

    + + +

    L

    N

    MMMMMMM

    O

    Q

    PPPPPPP

    1 1 2 12 3 123 2 12 3 123 3 1230

    1 1 2 12 3 123 2 12 3 123 3 123

    1 1 1E

    l s l s l s l s l s l sJ l c l c l c l c l c l c

    = + + +

    0

    1 1 2 12 3 123 2 12 3 123 3 123

    1 1 2 12 3 123 2 12 3 123 3 123

    0 0 00 0 00 0 01 1 1

    J

    l s l s l s l s l s l sl c l c l c l c l c l c

    E =

    + + +

    L

    N

    MMMMMMM

    O

    Q

    PPPPPPP Movie SegmentAutomatic Parallel Parking, INRIA, ICRA 1999 video proceedings

  • 14

    Stanford Scheinman Arm

    d2d3

    x0

    z0y0

    1{0}

    2

    x6 y6z6

    4 5

    6

    i i-1 ai-1 di i1 0 0 0 12 -90 0 d2 23 90 0 d3 04 0 0 0 45 -90 0 0 56 90 0 0 6

    T =i - 11

    ci -si 0 ai-1si ci-1 ci ci-1 -si-1 -s i-1 disi si-1 ci si-1 ci-1 ci-1 di

    0 0 0 1

    T = T T ... T0N0

    1

    1

    2

    N-1

    NForward Kinematics:

    0 0 0

    01 2 3

    0 0 0 0 01 2 4 5 6

    0 0 0

    0

    P P Px x xJ q q q

    Z Z Z Z Z

    = c d s s d c c d c ss d c s d s c d s s

    s d cs c s c c s s c c c c s s s s c s cc s s s c s c c s c c s c s s s s c

    c s s s c s c c

    +

    +

    + + + +

    L

    N

    MMMMMMM

    O

    Q

    P1 2 1 2 3 1 2 3 1 21 2 1 2 3 1 2 3 1 2

    2 3 2

    1 1 2 1 2 4 1 4 1 2 4 5 1 4 5 1 2 5

    1 1 2 1 2 4 1 4 1 2 4 5 1 4 5 1 2 5

    2 2 4 2 4 5 5 2

    0 0 00 0 0

    0 0 0 00 00 01 0 0

    PPPPPP

    Stanford Scheinman Arm Jacobian

    5 k =

    1 2 1 2 3 1 2 3 1 2

    1 2 1 2 3 1 2 3 1 2

    2 3 2

    1 1 2 1 2 4 1 4 1 2

    1 1 2 1 2 4 1 4 1 2

    2 2 4 2

    0 0 00 0 0

    0 0 0 00 00 01 0 0

    cd s s d cc d c ss d c s d sc d s s

    s d cJ

    s c s cc s s c c sc s s sc s cc s s

    c s s c

    + = +

    Stanford Scheinman Arm Jacobian Jacobian at the End-Effector

    Pne{n}

    {e}nvn

    eve

    v v Pe n n ne= + v v Pe n ne n

    e n

    = =

    RST

  • 15

    v vee

    n

    n FHGIKJ =FHGIKJFHGIKJ

    Pne

    J Je n= FHGIKJ

    Pne

    v v Pe n ne ne n

    = =

    RST

    J q J qe n = FHGIKJ

    Pne

    00

    0

    0J I P

    IJe ne n= FHGIKJ

    Cross Product Operator (in diff. frames)

    0 0 0P R P R Pnn

    nn= ( . ) .

    0 0 0P R Pnn n = .( )

    0 0 0 0 0 0 . .( . ) .( . . )P R P R P Rn n n n n n T = =0 0 0 n T

    n nP R P R=

    0 0 ;nnP R P

    Pne{n}

    {e}nvn

    eve

    nP

    0 0 00

    0

    0

    n Tnn n ne n

    e nn

    R R P RJ JR

    =

    i ji

    ji

    jJR

    RJ=FHGIKJ

    00 l1

    l2

    l3 W

    E Wrist Pointx l c l cy l s l s

    = += +

    1 1 2 12

    1 1 2 12

    End-Effector Pointx l c l c l cy l s l s l s

    = + += + +

    1 1 2 12 3 123

    1 1 2 12 3 123

    l1

    l2

    l3 W

    E Wrist Pointx l c l cy l s l s

    = += +

    1 1 2 12

    1 1 2 12

    End-Effector Pointx l c l c l cy l s l s l s

    = + += + +

    1 1 2 12 3 123

    1 1 2 12 3 123Jacobian (W)

    J

    l s l s l sl c l c l c

    W =

    +

    L

    N

    MMMMMMM

    O

    Q

    PPPPPPP

    1 1 2 12 2 12

    1 1 2 12 2 12

    00

    0 0 00 0 00 0 01 1 1

    00

    0

    0J I P

    IJE WE W= FHGIKJ

    ;

    l1

    l2

    l3 W

    E Wrist Pointx l c l cy l s l s

    = += +

    1 1 2 12

    1 1 2 12

    End-Effector Pointx l c l c l cy l s l s l s

    = + += + +

    1 1 2 12 3 123

    1 1 2 12 3 123

    J

    l s l s l sl c l c l c

    W =

    +

    L

    N

    MMMMMMM

    O

    Q

    PPPPPPP

    1 1 2 12 2 12

    1 1 2 12 2 12

    00

    0 0 00 0 00 0 01 1 1

    0

    1 1 2 12 3 123 2 12 3 123 3 123

    1 1 2 12 3 123 2 12 3 123 3 123

    0 0 00 0 00 0 01 1 1

    J

    l s l s l s l s l s l sl c l c l c l c l c l c

    E =

    + + +

    L

    N

    MMMMMMM

    O

    Q

    PPPPPPP

  • 16

    l1

    l2

    l3 W

    E Wrist Pointx l c l cy l s l s

    = += +

    1 1 2 12

    1 1 2 12

    End-Effector Pointx l c l c l cy l s l s l s

    = + += + +

    1 1 2 12 3 123

    1 1 2 12 3 123

    J

    l s l s l sl c l c l c

    W =

    +

    L

    N

    MMMMMMM

    O

    Q

    PPPPPPP

    1 1 2 12 2 12

    1 1 2 12 2 12

    00

    0 0 00 0 00 0 01 1 1

    00

    0

    0J I P

    IJE WE W= FHGIKJ

    03 123

    3 1230

    3 123

    3 123

    3 123 3 1230

    0 00 0

    0P

    l cl s P

    l sl c

    l s l cWE WE=L

    NMMM

    O

    QPPP =

    F

    HGG

    I

    KJJ

    Resolved Motion Rate Control (Whitney 72)

    x J= ( )Outside singularities

    = J x1( )Arm at Configuration

    x f= ( )x x xd= = J x1

    + = +

    Resolved Motion Rate Control

    xJ -1

    q q

    Control

    Control

    Control

    Joint n

    Joint 2

    Joint 1q1

    qn

    q2 q2

    qn

    q1

    ForwardKinematics

    xdx

    Linear & Angular Motion Velocity Propagation

    J a c o b i a n Differential Motion

    Explicit Form Static Forces

    v p=

    F

    Angular/Linear Velocities/Forces

    v

    p F = p

    v

    p

    Fp

    v p= v p=

    p F = p F =

    Angular/Linear Velocities/Forces

    xy

    z

    xy

    z

    ( ) xy xy

    Fp p

    F =

    x y

    y x

    v pv p

    =

    v J = T FJ =

    ( )Tp F =

  • 17

    Jx = Velocity/Force Duality

    TFJ =

    n f

    1

    2

    3

    PropagationElimination of Internal forces

    Energy AnalysisVirtual Work

    Static Equilibrium1

    n f

    2

    3

    n f

    1

    2

    3

    n f

    -f -nlink 3n3 f3

    -n1

    -f1

    -f2

    -n2n1

    f1

    link 1

    -n3

    f2

    n2 link 2-f3

    Link i

    Pi+1

    ni fi

    -fi+1 -ni+1

    forces = 0 moments / a point = 0

    About origin {i}f fn n P fi i

    i i i i

    + =+ + =

    +

    + + +

    ( )( ) ( )

    1

    1 1 1

    00

    f fn n P fi i

    i i i i

    == +

    +

    + + +

    1

    1 1 1

    Static EquilibriumLink i

    Pi+1

    ni fi

    -fi+1 -ni+1

  • 18

    i zi

    fi

    i zi

    ni

    Prismatic Joint Revolute Joint i i T if Z= i i T in Z=Algorithm n n

    n

    nn

    n nn

    n

    ii i

    i ii

    ii i

    i ii

    ii

    ii

    f f

    n n P f

    f R f

    n R n P f

    == +

    == +

    +

    ++

    +

    ++

    + +

    1

    11

    1

    11

    1 1

    .

    .

    Virtual Work Principaln f

    1

    2

    3

    Ffn

    = FHGIKJ

    T Tq F x = x J q =T TF J =

    Static Equilibrium:If the virtual work done by applied forces is zero in displacements consistent with constraints

    Internalforces areworkless

    i ii

    w f x = appliedforces

    virtualdisplacements

    ( ) 0TF x =using

    TJ F =

    1

    2

    3

    = T q +

    Jx = Velocity/Force Duality

    TFJ =

    ( )1 2 21 2 2

    1 12 12

    1 12 12

    l S l S l SJ

    l C l C l C

    + = +

    Example (Static Forces)

    l1

    l2

    1y

    {0}

    {1}

    2

    (x,y)

    ( )1 2 1 22 2

    1 12 1 12

    12 12T l S l S l C l CJ

    l S l C

    + + = TJ F =

    ( ) 1 21 2 1 222 2

    1 121 12 1 12 01 1212 12

    l C l Cl S l S l C l Cl Cl S l C

    + + + = = =

    1N

    1 2 1 21; 0; 60l l = = = = D3/ 21/ 2

    Example (Static Forces)

    l1

    l2

    1y

    {0}

    {1}

    2

    (x,y)

    TJ F =( ) 1 21 2 1 2

    22 2

    1 121 12 1 12 0( 1 )

    1 1212 12

    l C l Cl S l S l C l CK

    K l Cl S l C + + + = = =

    1000N

    1 2 1 21; 90; 0l l = = = = D

    00

    l2

    y{1}

    (x,y)

    1000N