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uw-biorobotics / IKBT

A python package to solve robot arm inverse kinematics in symbolic form
https://www.jair.org/index.php/jair/article/view/11592
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Panda Robot IK Solutions #46

Open aabouman opened 2 years ago

aabouman commented 2 years ago

Thanks for a really sweet package. I have been trying to compute the analytical solution for the first 6 joints of the Franka Panda robot with DH Parameters listed here. Adding the following to ik_robots.py:

    if(name == 'Panda'):

        dh = sp.Matrix([                  ##  This one requires sum-of-angles.
        [  0,         0,  l_1,  th_1],
        [-sp.pi/2,    0,    0,  th_2],
        [ sp.pi/2,    0,  l_3,  th_3],
        [ sp.pi/2,  a_1,    0,  th_4],
        [-sp.pi/2,  a_2,  l_5,  th_5],
        [ sp.pi/2,    0,    0,  th_6]
        ])
        vv = [1,1,1,1,1,1]
        sp.var('a_1 a_2 l_1 l_3 l_5')
        variables =  [unknown(th_1), unknown(th_2), unknown(th_3), unknown(th_4), unknown(th_5), unknown(th_6)]

        params = [a_1, a_2, l_1, l_3, l_5]
        pvals = {a_1:0.0825, a_2:-0.0825, l_1:0.333, l_3:0.316, l_5:0.384}

and running python3 ikSolver.py Panda results in the error: 


          Running IK solution 

             Working on Panda

kinematics pickle: trying to open  fk_eqns/Panda_pickle.p  in  /home/alexander/work/SymbolicIK/IKBT
\Trying to read pre-computed forward kinematics from fk_eqns/Panda_pickle.p
Successfully read pre-computed forward kinematics
pickle contained  6  unknowns
GOT HERE: robot name:  Panda
Ticking IK BT for  Panda  -------------------------

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3
x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4
[]
matching.py: bad notation collection

From a previous issue I figured this matching.py error ultimately means the solver is unable to compute a solution however I just wanted to check. Thanks!

blake5634 commented 2 years ago

Thanks for your interest. I like the challenge of "unsolvable" robots because most commercial designs have analytical solutions these days. If I get some time I'll take a look. Blake

On Wed, Jun 15, 2022 at 1:53 PM Alexander Addison Bouman < @.***> wrote:

Thanks for a really sweet package. I have been trying to compute the analytical solution for the first 6 joints of the Franka Panda robot with DH Parameters listed here https://frankaemika.github.io/docs/control_parameters.html. Adding the following to ik_robots.py:

if(name == 'Panda'):

    dh = sp.Matrix([                  ##  This one requires sum-of-angles.
    [  0,         0,  l_1,  th_1],
    [-sp.pi/2,    0,    0,  th_2],
    [ sp.pi/2,    0,  l_3,  th_3],
    [ sp.pi/2,  a_1,    0,  th_4],
    [-sp.pi/2,  a_2,  l_5,  th_5],
    [ sp.pi/2,    0,    0,  th_6]
    ])
    vv = [1,1,1,1,1,1]
    sp.var('a_1 a_2 l_1 l_3 l_5')
    variables =  [unknown(th_1), unknown(th_2), unknown(th_3), unknown(th_4), unknown(th_5), unknown(th_6)]

    params = [a_1, a_2, l_1, l_3, l_5]
    pvals = {a_1:0.0825, a_2:-0.0825, l_1:0.333, l_3:0.316, l_5:0.384}

and running python3 ikSolver.py Panda results in the error:

      Running IK solution

         Working on Panda

kinematics pickle: trying to open fk_eqns/Panda_pickle.p in /home/alexander/work/SymbolicIK/IKBT \Trying to read pre-computed forward kinematics from fk_eqns/Panda_pickle.p Successfully read pre-computed forward kinematics pickle contained 6 unknowns GOT HERE: robot name: Panda Ticking IK BT for Panda -------------------------

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4

Assigner: variable on blackboard: th_5

Assigner: variable on blackboard: th_6

Assigner: variable on blackboard: th_1

Assigner: variable on blackboard: th_2

Assigner: variable on blackboard: th_3 x2y2 did not find suitable eqns

Assigner: variable on blackboard: th_4 [] matching.py: bad notation collection

From a previous issue I figured this matching.py error ultimately means the solver is unable to compute a solution however I just wanted to check. Thanks!

— Reply to this email directly, view it on GitHub https://github.com/uw-biorobotics/IKBT/issues/46, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABRXOSJAKW34DTTH5EHIZ7LVPI7FVANCNFSM5Y4TYG5Q . You are receiving this because you are subscribed to this thread.Message ID: @.***>

-- Blake Hannaford