% Linearize the plant at t=3s
tLinearize = 3;% Create slTuner interface
TunedBlocks = {'turntablePID','bicepPID','forearmPID',...
'wristPID','handPID','gripperPID'};
ST0 = slTuner('cst_robotarm',TunedBlocks,tLinearize);% Mark outputs of PID blocks as plant inputs
addPoint(ST0,TunedBlocks)% Mark joint angles as plant outputs
addPoint(ST0,'6 DOF Robot Arm')% Mark reference signals
RefSignals = {...
'ref Select/tREF',...
'ref Select/bREF',...
'ref Select/fREF',...
'ref Select/wREF',...
'ref Select/hREF',...
'ref Select/gREF'};
addPoint(ST0,RefSignals)In its simplest use, looptune only needs to know the target control bandwidth, which
should be at least twice the reciprocal of the desired response time. Here the desired
response time is 1 second so try a target bandwidth of 3 rad/s (bearing in mind that the
plant dynamics vary least near 10 rad/s).wc = 3; % target gain crossover frequency
Controls = TunedBlocks; % actuator commands
Measurements = '6 DOF Robot Arm'; % joint angle measurements
ST1 = looptune(ST0,Controls,Measurements,wc);Final: Peak gain = 0.957, Iterations = 10
Achieved target gain value TargetGain=1.A final value near or below 1 indicates that looptune achieved the requested bandwidth.
Compare the responses to a step command in angular position for the initial and tuned
controllers.T0 = getIOTransfer(ST0,RefSignals,Measurements);
T1 = getIOTransfer(ST1,RefSignals,Measurements);opt = timeoptions; opt.IOGrouping = 'all'; opt.Grid = 'on';13 Control System Tuning Examples