// model for an electrical motor
// The generated torque is calculated based on the
// applied voltage and current at the electrical terminals.
// The model includes mechanical inertia and friction
//
module motor(vp,vn,shaft)
 inout vp,vn,shaft;
 electrical vp,vn;
 rotational_omega shaft;

 parameter real km = 4.5;
 parameter real kf = 6.2;
 parameter real j = 0.004;
 parameter real d = 0.1;
 parameter real rm = 5.0;
 parameter real lm = 0.02;

 analog
 begin
   V(vp,vn)   <+ km*Omega(shaft) + rm*I(vp,vn)     + ddt(lm*I(vp, vn));
   Tau(shaft) <+ kf*I(vp,vn)     - d*Omega(shaft)  - ddt(j*Omega(shaft));
 end
endmodule