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--- ece4560:piktul:04pnp [2017/10/13 11:57] – pvela
+++ ece4560:piktul:04pnp [2024/08/20 21:38] (current) – external edit 127.0.0.1
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 Once raised, it returns to the home position.
-==== Repetetive ====
+==== Repetitive ====
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+=== Inverse Kinematics ==
+Recall that the inverse kinematics for this problem has two solutions that one can call the //left// or //right// arm solution (does it bend left or right).  We can also call it the //positive// or //negative// solution. For the correctly printed piktul workspace mats made of cardboard, there is an annular type region that represents the manipulator workspace.  Any position in the workspace is fair game for the end-effector input configuration.  The set of possible orientations might be limited.
+In principal, both the left and right solutions should be possible to achieve, however the piktul has angular limits that make one of the solutions preferred for different regions of space.  You should program the inverse kinematics to be flexible regarding the solution used. There are two options, one which is okay and one which is best.
+The okay option is to have an optional argument that indicates which of the two solutions to use.  The code may already have such a variable called ''solfact'' which is expected to be positive (+1) for one solution and negative (-1) for the other solution.  If not given or not possible to parse/evaluate then default to a specific solution.
+The best option is to solve for both, then see which of the two options is valid relative to the joint limits.  The first one to successfully pass the joint limit test should be returned.  A mixed solution is also possible, where ''solfact'' is given and that solution used but the arm switches to the other solution if it violates the limits.
+Either way, the inverse kinematics should be capable of returning a correct solution when given an end-effector configuration that can be achieved by the piktul.
+=== Pick and Place ===
 The member function code created for this should be somewhat generic.  I would recommend
 creating a pick and place routine for the joint angles that takes the pick and place revolute joint angles (2x3 vector), the target upper and lower heights (2 vector), the gripper widths (2 vector), and a timing vector specifying how long each part of the sequence should take, then creates the execution sequence and executes.  If the timing sequence is missing, then some default timing should be applied.  The pick and place routine for end-effector configurations should have a similar set of arguments and solve the inverse kinematics part to get the joint angles, then invoke the pick and place routine for joint angles.
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 The solution should not be hard-coded for the actual tasks given.  The scripts you've been given should act as a good starting point for how the pick and place functions should work. The demo will involve assessing both execution of the task, as well as ability to actually grip, pick up, and place the object.
+=== The Code ===
+The ''piktul'' class code, as left by your colleauge, was not entirely written. In fact, the ''inversekin'' class member function appears to be a copy paste from some other code.  Correct the member function definition to accept the proper arguments, which include the desired end-effector configuration and the optional ''solfact'' variable. Also, revise the function code to correctly perform the inverse kinematics calculation.
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