Pick the sphere object and place

[snow John]

Hello Mr Corke and everyone in this group , I want to implement the pick and place simulation with RTB，I added some code in this example： https://www.youtube.com/watch?v=4ddfhcbIr1Y&list=PLF58C18380E9B356F

My codes are as follows

mdl_puma560

p = [0.8 0 0];

T = transl(p) * troty(pi/2);

qr(1) = -pi/2;

qqr = p560.ikine6s(T, 'ru');

qrt = jtraj(qr, qqr, 50);

ae = [138 8];

p(1) = 1;

clf

plot_sphere(p, 0.05, 'y');%position of the ball

p560.plot3d(qrt, 'view', ae);

%% For pick and place

qr(1) = pi/2;

qrt = jtraj(qqr, qr, 50);

for i=1:1:length(qrt)

    T=p560.fkine(qrt(i,:));

    P=transl(T.t(:,1)')*transl(0,0,0.2)*trotz(-pi/2);%tool transfrom

    P=P(1:3,end);

p560.plot3d(qrt(i,:), 'view', ae);

clf

plot_sphere(P, 0.05, 'y');%plot moving sphere

end

p560.plot3d(qrt(i,:), 'view', ae);

The result：

Obviously the sphere is not on the end effect of the robot, So my question is that the tool’s frame transformation code is wrong here?  If there are other alternative solutions to achieve the grab simulation.

Best regards ,

- John.

[Peter Corke]

Hi John,

I tweaked your code a bit

 

mdl_puma560

p = [0.8 0 0];

T = transl(p) * troty(pi/2);

qr(1) = -pi/2;

qqr = p560.ikine6s(T, 'ru');

qrt = jtraj(qr, qqr, 50);  % path from qr' to T

 

ae = [138 8];

p(1) = 1;

clf

plot_sphere(p, 0.05, 'y');%position of the ball

 

p560.plot3d(qrt, 'view', ae, 'nowrist');  % animate moption to the ball

 

%% For pick and place

qr(1) = pi/2;

qrt = jtraj(qqr, qr, 50);  % path from T to qr'

 

clf

for i=1:length(qrt)

    T = p560.fkine(qrt(i,:)); % get EE pose

    Tball = T * SE3(0,0,0.2); %tool transfrom

    P = Tball.t;

    clf

    plot_sphere(P, 0.05, 'y');%plot moving sphere

    p560.plot3d(qrt(i,:), 'view', ae, 'nowrist');

 

    pause(0.1)

end

p560.plot3d(qrt(i,:), 'view', ae);

This is a nice demo, I should probably ship something like this :)  The main differences are:

- computing the position of the ball, you need to offset by z=0.2 in the wrist frame

- you clear the figure between drawing the robot and the ball, which means they are out by one time step

- plotting the ball before the robot stops flickering, not quite sure why...

- I turned the wrist frame off so it's easier to see what's going on.

- a bit of formatting, white space and comments make it easier for others to read your code.

peter

[snow John]

Hello，Prof. Peter  Corke ，

I want to improve the manipulability when the robot doing the pick and place task，And i have find a nice way in the paper“  NEO ：A Novel Expeditious Optimisation Algorithm for Reactive Motion Control of Manipulators  ” to make the trajectory have hight manipulability .But the source code  is in python to get the Manipulability jacobian use the rbt. jacobm() function, which are not good for my project in matlab environment. And the QPsolver toolbox maybe can be replacered with the quadprog function in matlab.

But i really not well-know the manipulability jacobian  、Hessian Tensor matrix、vec (.)、computation 

Could you please help me change this part with matlab codes, Thanks in advance.

Best,

-Jian

[Peter Corke]

Hi John,

Sorry, but you are on your own with this.  This is my hobby, not my day job, and I don’t have the cycles to maintain/extend two toolboxes.  It shouldn’t be too hard to port to MATLAB, or you could call the Python code from MATLAB - theoretically possible but maybe harder than doing a port.  Calling RTB-P from MATLAB is on my long list of things to look at.

Peter

On 25 Nov 2022, at 11:31 pm, snow John <jianr...@gmail.com> wrote:

Hello，Prof. Peter  Corke ，

I want to improve the manipulability when the robot doing the pick and place task，And i have find a nice way in the paper“  NEO ：A Novel Expeditious Optimisation Algorithm for Reactive Motion Control of Manipulators  ” to make the trajectory have hight manipulability .But the source code  is in python to get the Manipulability jacobian use the rbt. jacobm() function, which are not good for my project in matlab environment. And the QPsolver toolbox maybe can be replacered with the quadprog function in matlab.

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