Motor drive u = * x + * v
Run the Model The drive is now limited in magnitude to 1.
You can apply a disturbing force to the motion,
disturbance = 0

<![CDATA[ function setup(){ tmax=30; ScaleWindow(-1,-3,tmax,3); DrawAxes(0,-3,tmax,3); kx=posgain.value; kv=velgain.value; temp=0; b=1; dt=.01; t=0; x=2; //Initial position v=0; u=0; //Input motor current Colour('blue'); Label('Velocity',10,1); Colour('gray'); Label('Drive u',10,0.8); MoveTo (t, x); Colour('black'); loop(); } ]]>
<![CDATA[ function loop(){ u = kx*x + kv*v; //This calculates the motor drive Colour('black'); if (u>1){u=1; Colour('red');} //This applies the limit if (u<-1){u=-1; Colour('red');} x = x + v*dt; //This is the simulation v = v + (b*u+disturbance)*dt; t = t + dt; Spot(t, x); Colour('gray'); Spot(t,u); Colour('blue'); Spot(t,v); if(t<tmax){setTimeout('loop();', 1000*dt);} //loop again } ]]>