femm.py

class Simulation:
    def __init__(self):
        self.commands = ["newdocument(0)", "showconsole()", 'mi_probdef(0, "millimeters", "planar", 1E-8)']

        self.points = {}
        self.materials = {}
        self.circuits = 0

    def run_sim(self):
        self.commands += ['mi_saveas("Untitled.fem")', "mi_analyse()", "mi_loadsolution()"]

    def calculate_force(self, blocks):
        self.commands += ['mo_seteditmode("area")']

        for i in blocks:
            self.commands += ['mo_selectblock({}, {})'.format(i[0], i[1])]

        self.commands += ['print(mo_blockintegral(18))']


    def add_point(self, x, y):
        if (x, y) not in self.points:
            self.commands += ["mi_addnode({}, {})".format(x, y)]
            self.points[(x, y)] = 0

    def draw_line(self, x1, y1, x2, y2):
        self.add_point(x1, y1)
        self.add_point(x2, y2)

        self.commands += ["mi_addsegment({}, {}, {}, {})".format(x1, y1, x2, y2)]

    def rect_with_mat(self, x1, y1, x2, y2, name, mag_angle=0, current=0):
        self.draw_contour([
            (x1, y1),
            (x1, y2),
            (x2, y2),
            (x2, y1),
        ])

        self.set_materials((x1 + x2) / 2, (y1 + y2) / 2, name, mag_angle, current)

    def draw_contour(self, l):
        for iind, i in enumerate(l):
            j = l[iind - 1]

            self.draw_line(i[0], i[1], j[0], j[1])

    def create_boundaries(self):
        x = []
        y = []
        for k, v in self.points.items():
            x.append(k[0])
            y.append(k[1])

        x_center = (max(x) - min(x)) / 2 + min(x)
        y_center = (max(y) - min(y)) / 2 + min(y)

        r = max(max(x) - min(x), max(y) - min(y))

        self.commands += ["mi_makeABC(7, {}, {}, {}, {})".format(r, x_center, y_center, 0)]

    def add_materials(self, name):
        if name not in self.materials:
            self.materials[name] = 0
            self.commands += ['mi_getmaterial("{}")'.format(name)]

    def set_materials(self, x, y, name, mag_angle=0, current=0):
        self.add_materials(name)

        current_str = ""
        if current != 0:
            self.circuits += 1
            self.commands += ['mi_addcircprop("circuit{}", {}, 1)'.format(self.circuits, current, 1)]
            current_str = "circuit" + str(self.circuits)

        self.commands += ["mi_clearselected()"]
        self.commands += ["mi_addblocklabel({}, {})".format(x, y)]
        self.commands += ["mi_selectlabel({}, {})".format(x, y)]
        self.commands += ['mi_setblockprop("{}", 1, 0, "{}", {}, 0, 1)'.format(name, current_str, mag_angle)]

    def output(self):
        return "\n\r".join(self.commands)


class Motor:
    def __init__(self):
        self.teeth_height = 1
        self.notch_height = 6

        self.teeth_width = 8
        self.notch_width = 2

        self.air_gap = 1

        self.back_iron_thickness = 3

        self.magnet_width = 6
        self.magnet_thickness = 2
        self.magnet_space = 1

        self.offset = 0

    def build_magnets(self, x, sim, a):
        if a:
            a1 = 90
        else:
            a1 = 270

        sim.rect_with_mat(x, (self.notch_height + self.teeth_height) / 2 + self.air_gap,
                          x + self.magnet_width,
                          (self.notch_height + self.teeth_height) / 2 + self.air_gap + self.magnet_thickness,
                          "NdFeB 40 MGOe", mag_angle=a1)

        sim.rect_with_mat(x, -(self.notch_height + self.teeth_height) / 2 - self.air_gap,
                          x + self.magnet_width,
                          -(self.notch_height + self.teeth_height) / 2 - self.air_gap - self.magnet_thickness,
                          "NdFeB 40 MGOe", mag_angle=a1)
    def build(self):
        sim = Simulation()

        sim.draw_contour([(self.notch_width / 2, self.notch_height / 2),
                          (self.notch_width / 2, -self.notch_height / 2),
                          (self.teeth_width / 2, -self.notch_height / 2),
                          (self.teeth_width / 2, -self.notch_height / 2 - self.teeth_height),
                          (-self.teeth_width / 2, -self.notch_height / 2 - self.teeth_height),
                          (-self.teeth_width / 2, -self.notch_height / 2),
                          (-self.notch_width / 2, -self.notch_height / 2),
                          (-self.notch_width / 2, self.notch_height / 2),
                          (-self.teeth_width / 2, self.notch_height / 2),
                          (-self.teeth_width / 2, self.notch_height / 2 + self.teeth_height),
                          (self.teeth_width / 2, self.notch_height / 2 + self.teeth_height),
                          (self.teeth_width / 2, self.notch_height / 2),
                          ])

        sim.draw_line(self.teeth_width / 2, self.notch_height / 2, self.teeth_width / 2, -self.notch_height / 2)
        sim.draw_line(-self.teeth_width / 2, self.notch_height / 2, -self.teeth_width / 2, -self.notch_height / 2)

        sim.set_materials(0, 0, "M-36 Steel")
        sim.set_materials((self.teeth_width - self.notch_width) / 2, 0, "Copper", current=50 * 9)
        sim.set_materials(-(self.teeth_width - self.notch_width) / 2, 0, "Copper", current=-50 * 9)

        for i in range(4):
            self.build_magnets((i - 2) * (self.magnet_width + self.magnet_space) + self.magnet_space/2, sim, i % 2)

        sim.rect_with_mat(-2 * (self.magnet_width + self.magnet_space), (self.notch_height + self.teeth_height) / 2 + self.air_gap + self.magnet_thickness,
                          2 * (self.magnet_width + self.magnet_space), (self.notch_height + self.teeth_height) / 2 + self.air_gap + self.magnet_thickness + self.back_iron_thickness,
                          "M-36 Steel")

        sim.rect_with_mat(-2 * (self.magnet_width + self.magnet_space), -(self.notch_height + self.teeth_height) / 2 - self.air_gap - self.magnet_thickness,
                          2 * (self.magnet_width + self.magnet_space), -(self.notch_height + self.teeth_height) / 2 - self.air_gap - self.magnet_thickness - self.back_iron_thickness,
                          "M-36 Steel")

        sim.set_materials(0, (self.notch_height + self.air_gap / 2) / 2 + self.teeth_height, "Air")

        sim.create_boundaries()
        sim.run_sim()

        sim.calculate_force([(0, 0), (self.teeth_width / 2 - 0.01, 0), ( - self.teeth_width / 2 + 0.01, 0)])

        print(sim.output())


m = Motor()
m.build()