Figure 7: Input voltage to DC motors (control signal).
Second, cross-coupling effects between the Wrist and Bicep, when brought to scale, have
a significant and lasting impact on the Bicep response. To see this, plot the step response
of these three joints for the actual step changes occurring during the maneuver (-10 deg
for the Bicep joint and 90 degrees for the Wrist joint).
H2 = T2([2 4],[2 4]) * diag([-10 90]); % scale by step amplitude
H2.u = {'Bicep','Wrist'};
H2.y = {'Bicep','Wrist'};
step(H2,5), grid
Multi-Loop PI Control of a Robotic Arm