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control and design applying ramp input and plotting polar coordinates state space



I am trying to do a fairly simple state space task with Control Design and Simulation toolbox, however I am quite new at using this toolbox and need some help 🙂


I want to simulate a MIMO system of a 2-DOF robot arm. The robot arm consists of two links, the first link can rotate arround its origo at its end, and the next link moves inside the first link, in and out.

So the two outputs is define as

  • r (radius), which is the distance to the end-effector of the robot, and
  • theta, which is the angular postion of the robot arm

FYI, the two inputs are the currents send to the two motors controlling each link.


I have set up A, B, C and D matrices in the attached VI file and putted it inside a simulation loop.


Now I need help 🙂

I want to simulate the system when a ramp input is applied to the two inputs and plot the two outputs in a polar graph to show the end-effectors position when the system is just "let loose". The result should be a spiral (this is verified in MATLAB simulink).


So please, I need help setting up the VI to do the above, can anyone help?


Best regards


MSc. Eng.

Message Edited by SCMAJA on 10-16-2009 11:21 AM
LabVIEW 8.6 / 2009 / 2010
Vision Development Module 8.6 / 2009 / 2010
VBAI 3.6 / 2010
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Hello Simon,


The error comes from your Ramp Input. Since your system is MIMO, you would need to feed in a vector input to the system.

robot mimo.PNG


I've changed your VI and attached here~!



Andy Chang
National Instruments
LabVIEW Control Design and Simulation
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