Improve code quality of 4 specific modules

[mithi]

• hexapod.models
• hexapod.linkage
• hexapod.ik_solver.ik_solver
• hexapod.ground_contact_solver

https://github.com/mithi/hexapod-robot-simulator/blob/master/hexapod/models.py
https://github.com/mithi/hexapod-robot-simulator/blob/master/hexapod/linkage.py
https://github.com/mithi/hexapod-robot-simulator/blob/master/hexapod/ground_contact_solver.py
https://github.com/mithi/hexapod-robot-simulator/blob/master/hexapod/ik_solver/ik_solver.py

[mithi]

hexapod.models.VirtualHexapod()

• Reduce cognitive complexity of find_twist_frame, it's about 60 lines of code. Issue When the right middle coxia is twisted the whole hexapod twists #15

When the right middle coxia is twisted the whole hexapod twists
is related to this

• Improve Line 257 - 268

            # new alpha pose
            try:
                new_hip_angle = poses[leg_id]["coxia"]
            except KeyError:
                try:
                    new_hip_angle = poses[str(leg_id)]["coxia"]
                except KeyError:
                    new_hip_angle = 0

• Reduce cognitive complexity of hexapod.models.VirtualHexapod.update It's currently more than 40 lines of code

• Raise error instead of using None in Lines 189 - 210

Currently, it's like this:

        legs, self.n_axis, height = get_legs_on_ground(self.legs)
        self.ground_contacts = [leg.ground_contact() for leg in legs]

        # This means that the position is stable
        if self.n_axis is not None:
            # tilt and shift the hexapod based on new normal
            frame = frame_to_align_vector_a_to_b(self.n_axis, Point(0, 0, 1))
            self.rotate_and_shift(frame, height)
            self._update_local_frame(frame)

            # Only twist if we computed earlier that at least three hips twisted
            if might_twist:
                twist_frame = find_twist_frame(
                    old_ground_contacts, self.ground_contacts
                )
                self.rotate_and_shift(twist_frame, 0)
        else:
            pass

It should be something like

try:
     legs, self.n_axis, height = get_legs_on_ground(self.legs)
except:
    raise Error('Unstable pose')

self.ground_contacts = [leg.ground_contact() for leg in legs]
# tilt and shift the hexapod based on new normal
frame = frame_to_align_vector_a_to_b(self.n_axis, Point(0, 0, 1))
self.rotate_and_shift(frame, height)
self._update_local_frame(frame)

# Only twist if we computed earlier that at least three hips twisted
if might_twist:
    twist_frame = find_twist_frame(old_ground_contacts,  self.ground_contacts)
    self.rotate_and_shift(twist_frame, 0)

[mithi]

hexapod.models.VirtualHexapod()

• Rethink and reevaluate this function, how can we make it more elegant? Reevaluate the algorithm
  

  hexapod-robot-simulator/hexapod/models.py

  Line 268 in f67434e

  def find_twist_frame(old_ground_contacts, new_ground_contacts):

• Move
  

  hexapod-robot-simulator/hexapod/models.py

  Line 222 in f67434e

  def _find_if_might_twist(self, poses):

To an independent function which is not a method of hexapod.models.VirtualHexapod

• I don't thing anyone uses the lists
  self.body_dimensions and self.leg_dimensions maybe we should delete that

• change _store_body_dimensions() function name to _store_attributes() which is more meaningful
  

  hexapod-robot-simulator/hexapod/models.py

  Line 201 in f67434e

  def _store_body_dimensions(self, f=0, m=0, s=0, a=0, b=0, c=0):

• hexapod.models.VirtualHexapod.update() could definitely be more elegant
  

  hexapod-robot-simulator/hexapod/models.py

  Line 167 in f67434e

  def update(self, poses):