Simulink Control Design™ - MathWorks

(outputs of PID blocks) and the measurement signals (output of "6 DOF Robot Arm"

block).

SnapshotTimes = 0:1:5;

% Plant is from PID outputs to Robot Arm outputs

LinIOs = [...

linio('cst_robotarm/Controller/turntablePID',1,'openinput'),...

linio('cst_robotarm/Controller/bicepPID',1,'openinput'),...

linio('cst_robotarm/Controller/forearmPID',1,'openinput'),...

linio('cst_robotarm/Controller/wristPID',1,'openinput'),...

linio('cst_robotarm/Controller/handPID',1,'openinput'),...

linio('cst_robotarm/Controller/gripperPID',1,'openinput'),...

linio('cst_robotarm/6 DOF Robot Arm',1,'output')];

LinOpt = linearizeOptions('SampleTime',0); % seek continuous-time model

G = linearize('cst_robotarm',LinIOs,SnapshotTimes,LinOpt);

size(G)

6x1 array of state-space models.

Each model has 6 outputs, 6 inputs, and 19 states.

Plot the gap between the linearized models at t=0,1,2,3,4 seconds and the final model at

t=5 seconds.

G5 = G(:,:,end); % t=5

G5.SamplingGrid = [];

sigma(G5,G(:,:,2:5)-G5,{1e-3,1e3}), grid

title('Variation of linearized dynamics along trajectory')

legend('Linearization at t=5 s','Absolute variation',...

'location','SouthWest')

13 Control System Tuning Examples