search

AngelLM / Thor

DIY 3D Printable Robotic Arm
Creative Commons Attribution Share Alike 4.0 International
928 stars 223 forks source link

cinematic motion algorithm #64

Closed mkeyno closed 3 years ago

mkeyno commented 7 years ago

hi, sorry to open ticket for my question , but actually I'm little lost to find the methods can convert input location (Cartesian , polar) to the optimized cinematic motions of each axis? for example how to defined the best path from A to B coordinates and how it converted the cinematic motion for each axis? what is the optimization function & type ?how to define cinematic motion parameters of specific arms? I really appreciated for your hint

i-make-robots commented 7 years ago

what do you mean when you say "cinematic" motion?

i-make-robots commented 7 years ago

Thor does not, at this time, afaik, have a motion planning software that would, say, let you plot lines in space and then move the arm to meet those points, like this: https://www.youtube.com/watch?v=AO57-fZUWho

mkeyno commented 7 years ago

sorry I mean kinematic , you know, every robot has its own physical parts and degree of freedom so to define path between two given points we need the calculate some dynamic equations to find this patch and other parameters(like velocity and acceleration ) , however there is no unique path between two given points , thus some optimization algorithm applied to find the best and smooth path , I saw couple of repo use the CNC planner code to implemented this path but not find yet the path optimization algorithm

i-make-robots commented 7 years ago

Frequently the shortest path is taken. I know the number of steps each motor must take and the speed of the slowest motor. I then step all motors so that they arrive simultaneously at the destination. There are times when this solution is bad - it does not take into account impossible geometries or singularities BUT if you can avoid them it works great.

i-make-robots commented 7 years ago

sorry, to calculate the kinematics is how you get the number of steps of each motor. I have some examples in https://github.com/MarginallyClever/Robot-Overlord-App/ for 4 and 5 DOF arms. Maybe that will help? I don't remember atm if THOR is supported yet, but I'd like to see it happen.

AngelLM commented 7 years ago

Hi! Sorry for the late reply. Currently Thor moves using Forward Kinematics (at least mine). The calculations involved in the movement are responsibility of the firmware (GRBL). At this time there is not implemented neither a control using Inverse Kinematics nor movement optimization. If it helps here it's the solution for the Forward Kinematics. And here the solution of the Inverse Kinematics of Thor. Also, @Danny-VdH were developing a GUI to control robotic arms. You can chek it out too ;)

Hope it helps!

i-make-robots commented 7 years ago

If I have the relative distance between each joint in the system and an simplified STL of each THOR part I could add it to Robot Overlord. Then it would send FK commands to the arm, much as it does with my other robots. If that's of interest to you, make it so. I could get it implemented before the end of August.

AngelLM commented 7 years ago

@i-make-robots That sounds good! I think that you have all the distances you need in this image.

i-make-robots commented 7 years ago

I explained myself badly. I need an STL of each section - the base, the shoulder, the bicep, the ulna, the wrist. For each part, I need the origin of the part to be at the point of rotation or, in the case of the base, at the world origin. For each part I also need a measurement of the distance from the origin to the axis of rotation of the next part. In the case of the base, I need to know how far up to reach the point where the shoulder rotates. the shoulder origin would be at that spot, and the relative distance from there to the rotation point of the bicep, and so on. Does that make more sense?

I can spend hours monkeying around trying to fix it in software but I've got very limited time. I'm hoping we can help each other, here.

On Mon, Aug 7, 2017 at 2:32 PM, AngelLM notifications@github.com wrote:

@i-make-robots https://github.com/i-make-robots That sounds good! I think that you have all the distances you need in this image https://github.com/AngelLM/Thor/blob/developer/doc/ThorDimensions.png.

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/AngelLM/Thor/issues/64#issuecomment-320786558, or mute the thread https://github.com/notifications/unsubscribe-auth/ABZYhr-jMa9c6Bmj7N985RLIRL97RQ3wks5sV4JcgaJpZM4OtoJJ .

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 Mo: +1 (604) 916-2281

AngelLM commented 7 years ago

Hi @i-make-robots I just upload the STL files of each articulation Also, the distances are the following, understanding global positions as the XYZ coordinates of the space and the local position as the XYZ coordinates of the piece. Both coordinates are expressed in mm.

I don't really know if the STL of the last 2 articulation will work (because of coupled movements). Probably splitting it into 2 pieces (the column + gears for the 5th and the rest for the 6th) would make the work. I'll do it now, just in case.

AngelLM commented 7 years ago

Split done. The new distances would be:

i-make-robots commented 7 years ago

are you sure about articulation 2, distance 65? looking at the parts together it looks more like 85 or 90.

On Tue, Aug 8, 2017 at 4:25 AM, AngelLM notifications@github.com wrote:

Split done. The new distances would be:

  • Articulation 5
    • Global position (X,Y,Z): 0,0,510
    • Art Rotation axis: Y
    • Art Rotation axis local position (X,Y,Z): 0,0,47
  • Articulation 6
    • Global position (X,Y,Z): 0,0,610.431
    • Art Rotation axis: Z
    • Art Rotation axis local position (X,Y,Z): 0,0,0

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/AngelLM/Thor/issues/64#issuecomment-320927692, or mute the thread https://github.com/notifications/unsubscribe-auth/ABZYhh0SQm-QViQZNVUfUExYhktaBzpUks5sWEW9gaJpZM4OtoJJ .

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 Mo: +1 (604) 916-2281

i-make-robots commented 7 years ago

ok, I have the model displaying after adjusting the origins. You'll probably want to split the gripper tool from the wrist component. Biggest reason so you can animate the gripper action. I'll take some more time later this week to implement FK.

On Tue, Aug 8, 2017 at 8:40 AM, Dan Royer dan@marginallyclever.com wrote:

are you sure about articulation 2, distance 65? looking at the parts together it looks more like 85 or 90.

On Tue, Aug 8, 2017 at 4:25 AM, AngelLM notifications@github.com wrote:

Split done. The new distances would be:

  • Articulation 5
    • Global position (X,Y,Z): 0,0,510
    • Art Rotation axis: Y
    • Art Rotation axis local position (X,Y,Z): 0,0,47
  • Articulation 6
    • Global position (X,Y,Z): 0,0,610.431
    • Art Rotation axis: Z
    • Art Rotation axis local position (X,Y,Z): 0,0,0

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/AngelLM/Thor/issues/64#issuecomment-320927692, or mute the thread https://github.com/notifications/unsubscribe-auth/ABZYhh0SQm-QViQZNVUfUExYhktaBzpUks5sWEW9gaJpZM4OtoJJ .

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 <(604)%20259-9564> Mo: +1 (604) 916-2281 <(604)%20916-2281>

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 Mo: +1 (604) 916-2281

i-make-robots commented 7 years ago

aaaand now i have FK working, kind of. Fingers crossed I can get IK working just as easily.

On Tue, Aug 8, 2017 at 9:48 AM, Dan Royer dan@marginallyclever.com wrote:

ok, I have the model displaying after adjusting the origins. You'll probably want to split the gripper tool from the wrist component. Biggest reason so you can animate the gripper action. I'll take some more time later this week to implement FK.

On Tue, Aug 8, 2017 at 8:40 AM, Dan Royer dan@marginallyclever.com wrote:

are you sure about articulation 2, distance 65? looking at the parts together it looks more like 85 or 90.

On Tue, Aug 8, 2017 at 4:25 AM, AngelLM notifications@github.com wrote:

Split done. The new distances would be:

  • Articulation 5
    • Global position (X,Y,Z): 0,0,510
    • Art Rotation axis: Y
    • Art Rotation axis local position (X,Y,Z): 0,0,47
  • Articulation 6
    • Global position (X,Y,Z): 0,0,610.431
    • Art Rotation axis: Z
    • Art Rotation axis local position (X,Y,Z): 0,0,0

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/AngelLM/Thor/issues/64#issuecomment-320927692, or mute the thread https://github.com/notifications/unsubscribe-auth/ABZYhh0SQm-QViQZNVUfUExYhktaBzpUks5sWEW9gaJpZM4OtoJJ .

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 <(604)%20259-9564> Mo: +1 (604) 916-2281 <(604)%20916-2281>

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 <(604)%20259-9564> Mo: +1 (604) 916-2281 <(604)%20916-2281>

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 Mo: +1 (604) 916-2281

i-make-robots commented 7 years ago

Right, IK looks to be mostly working. I've done the first 95%, please contribute whatever you can to make it even better.

https://www.instagram.com/p/BXi0Ci4gLqb/

On Tue, Aug 8, 2017 at 10:44 AM, Dan Royer dan@marginallyclever.com wrote:

aaaand now i have FK working, kind of. Fingers crossed I can get IK working just as easily.

On Tue, Aug 8, 2017 at 9:48 AM, Dan Royer dan@marginallyclever.com wrote:

ok, I have the model displaying after adjusting the origins. You'll probably want to split the gripper tool from the wrist component. Biggest reason so you can animate the gripper action. I'll take some more time later this week to implement FK.

On Tue, Aug 8, 2017 at 8:40 AM, Dan Royer dan@marginallyclever.com wrote:

are you sure about articulation 2, distance 65? looking at the parts together it looks more like 85 or 90.

On Tue, Aug 8, 2017 at 4:25 AM, AngelLM notifications@github.com wrote:

Split done. The new distances would be:

  • Articulation 5
    • Global position (X,Y,Z): 0,0,510
    • Art Rotation axis: Y
    • Art Rotation axis local position (X,Y,Z): 0,0,47
  • Articulation 6
    • Global position (X,Y,Z): 0,0,610.431
    • Art Rotation axis: Z
    • Art Rotation axis local position (X,Y,Z): 0,0,0

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/AngelLM/Thor/issues/64#issuecomment-320927692, or mute the thread https://github.com/notifications/unsubscribe-auth/ABZYhh0SQm-QViQZNVUfUExYhktaBzpUks5sWEW9gaJpZM4OtoJJ .

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 <(604)%20259-9564> Mo: +1 (604) 916-2281 <(604)%20916-2281>

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 <(604)%20259-9564> Mo: +1 (604) 916-2281 <(604)%20916-2281>

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 <(604)%20259-9564> Mo: +1 (604) 916-2281 <(604)%20916-2281>

-- Dan Royer, Owner, Marginally Clever Robots https://www.marginallyclever.com/ Ph: +1 (604) 259-9564 Mo: +1 (604) 916-2281

AngelLM commented 7 years ago

I saw it! Awesome work! Expect some contributions and feedback from my side! :)