------------------------------------------
-- Analysis of a Woofer Motor           --
--                                      --   
-- David Meeker                         -- 
-- dmeeker@ieee.org                     --
--                                      --
-- 15 May2009                           --
--                                      --
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-- Introduction
--
-- The purpose of this script is to automate the analysis of a woofer motor.
-- The notebook produces the static performance curves that designers often
-- desire during the development of a new transducer: the actuator's "BL" 
-- (the amount of force produced on the voice coil per amp of coil current); 
-- the coil's self-inductance, and a plot of the magnetic field in which the 
-- coil is immersed.
--
-- Because there are so many possible variations in speaker motor geometry,
-- the notebook does not create the speaker geometry within the notebook.  Rather, 
-- it reads an existing geometry info FEMM and analyses it at a number of different
-- coil locations. It is assumed that the speaker motor has been drawn with all
-- elements in the coil belonging to group number 1, so that the voice coil can
-- be easily selected and moved by the notebook.  It is also assumed that the .fem
-- file describing the motor is located in the same directory as the notebook 
-- (although the user could manually change the path to the .fem file).

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-- Design - Specific Parameters
--------------------------------------

-- Model Name
ModelName = 'Woofer.fem';

-- Maximum excursion + /- from the centered position:
Xlim = 5;

-- Movement increments used during the analysis
dX = 1;

--------------------------------------
-- Analysis Routines
--------------------------------------

-- Analyze BL and incremental inductance at 1 mm steps between - Xlim and + Xlim
open(ModelName);
mi_saveas('temp.fem');
mi_selectgroup(1);
mi_movetranslate(0, -Xlim);
mi_clearselected();

showconsole();
clearconsole();

print('---------------------------------------------')
print(' Speaker Motor Analysis Script');
print('');
print(' David Meeker');
print(' dmeeker@ieee.org');
print(' 15May2009');
print('---------------------------------------------');
print('');
print('Disp(mm)','BL(N/A)','Inductance(uH)');
for k=-Xlim,Xlim,dX do
    mi_modifycircprop('icoil',1,1);
    mi_analyze(1);
    mi_loadsolution();
    mo_groupselectblock(1);
    fz = mo_blockintegral(12);
    parm1,R,fl1 = mo_getcircuitproperties('icoil');
    mo_close();
    mi_modifycircprop('icoil', 1, 0);
    mi_analyze(1);
    mi_loadsolution();
    parm1,parm2,fl0 = mo_getcircuitproperties('icoil');
    L = (fl1 - fl0)*10^6;
    print(k, fz, L);
    mi_selectgroup(1);
    mi_movetranslate(0, 1);
end

mi_close();
remove('temp.fem');
remove('temp.ans');

print('');
print('DC coil resistance = ',R);