I am feeling so happy to have found your channel. Gone through most of the videos in playlist 1 and so many of my confusions are resolved now. Thumbs up for this great work.
Hello maam thank you for this informative video, but maam im having a question on my self that, am I right that the inverse kinematics itself can make my end effector move on my desired position? Is it really useful to solve for both the forward and inverse kinematics to know the joint variables for my target position or just the inverse kinematics? Its like i use inverse kinematics to find the joint variables required for my desired end effector position, if I find the joint variable by solving using inverse kinematics concept then I can already put those solved joint variables in my servos parameter to have my desired end effector position to be met. Then what does forward kinematics for in this situation?
Great videos! In this video you have mentioned that tangent solutions are more robust than sine and cosine. Just curious what might be the reason behind it. Loving your videos :)
Really good video, but in both inverse kinematic exercised what happen to l1 and a3? why you don't take them into consideration? and in the implementation of the program is it not better to implement atan2 instead of atan?
HI mam how are you doing I am an MSc student from Iraq and I realy depend on your videos to sucssed I wish I can find videos like this on Irtificial intilligent I realy having problems with it.. god bless you
In my rpbotics classes, we cover an introduction to Artificial Intelligence in the second-semester class, which will next begin in January 2018. So, I will be posting videos for that class throughout December. If you want to browse topics and follow the class timeline, take a look at my website, www.robogrok.com
Hi Angela :) Once again yours are the best videos on this topic on youtube, super helpful for those learning. You break stuff down into the underlying steps, making it far easier to follow. It eliminates a great deal of frustration and makes it more enjoyable. Can I ask a question on a further topic? In the Spong book he mentions that in IK you can have (obviously) more than one solution, but that a "set of rules" can be applied to ensure that any physical constraints, such as joint motion limits, can be identified and factored into the calculations. However he does not provide a means of creating such rules, at least that I have in the snippets of the book I found online. Can you recommend a resource that covers how to do this please, particularly in regards to programming a real machine? Keep on robotin'! :)
I am not sure what Spong meant by this, but I will make a guess: I think the 'rules' that can be applied to make sure we comply with physical constraints are actually rules in our code, rather than rules in our derivation of the equations. For example, when we write the inverse kinematics into our code in this video, we are writing the code for one servo that is limited to 0 degrees to 180 degrees, and another servo that is limited to -90 to 90 degrees. Now, suppose we put an input (X,Y) coordinate in the 4th quadrant, such as (8,-2). If we use 'elbow-down' equations to solve the inverse kinematics, the first joint angle will come out to something like 300 degrees or -60 degrees or something like that. That's clearly outside of the allowable range. But, if we use 'elbow-up' equations, the first joint angle will come out to something like 30 degrees, which IS inside the range. So, we could put some 'if' statements (rules) into our code that would first try the 'elbow-down' configuration, then check to see if the calculated angles are within the allowable range and, if not, try the 'elbow-up' configuration. At least, that's how I do it :). I'm not sure if that's what Spong actually meant or not.
Could it be that there’s a mistake in 4:27? Second row says a2stheta1 and in the equation below it says a2stheta2? So one is not correct. Maybe you can help
d1 is the amount that that joint has extended beyond its 0 position. The d variables change their values as the prismatic joints move. In contrast, the a variables are the lengths of links. These values are constant once the robot is built, and do not change as the robot joints move.
hi , video at 21.47 you put two joint and all of them turn z axis, in addition to that i wanna put the joint that it will turn the y axis or x axis (i put join like horizontal , y axis up ) , and i have to calculate inverse kinematic and i must see from top view , i know about turn z axis of joint like a circle , but how can i draw top view of the horizontal joint ?
İ draw like a rectangular and put the coordinant frame ? So, i was wondering , it doesnt matter what it looks like . The important one is link distance and correct koordinnt frame and calculate inverse kinematic ? Am i right ?
Angela Sodemann i want to have inverse Kinematics about it bcz the coordinates on it are over lapping from top view and from side there is no triangle to be formed...
Many thanks Angela. Yes on the website its much more clearer. Do you hv a lesson on inverse kinematics using trigonometry solution? I cant seem to find any on your site or anywhere on youtube.
There's a lot of trig involved in doing what I know as the 'geometric solution' to inverse kinematics; that might be the same thing as what you are referring to. You can find those videos here: www.robogrok.com/1-1-6_Inverse_Kinematics_of_a_SCARA_Manipulator.php
i cant thank you enough Angela. u hv given me an early xmas. thats what i hv been searching for a "geometric solution". thanks again i hv now subscribed.
