Changes

=== Important implentation notes===

=== Important implentation notes===

===Layperson "how it works"===

===Layperson "how it works"===

The central idea to spaghetti is an linear compensator that computes a control effort, given the history of measured altitudes. You don't need to know how it works. This control effort is in kg/s. It this then scaled by a gain, called k. Since ballasting and venting are discrete on/off, and the commanded effort is continuous, this needs to be converted into a series of discrete actions, separated by a time interval. This is much like PWM, but instead of changing duty cycle directly, you are changing the time interval between events such that the action time is fixed to it's minimum acceptable value, and produce the least discretization (in the future this may want to be changed to conserve power and minimize the number of valve actions).

The central idea to spaghetti is an linear compensator that computes a control effort, given the history of measured altitudes. You don't need to know how it works in order to command it. This control effort is in kg/s. It this then scaled by a gain, called k. Since ballasting and venting are discrete on/off, and the commanded effort is continuous, this needs to be converted into a series of discrete actions, separated by a time interval. This is much like PWM, but instead of changing duty cycle directly, you are changing the time interval between events such that the action time is fixed to it's minimum acceptable value, and produce the least discretization (in the future this may want to be changed to conserve power and minimize the number of valve actions).

===Constants===

===Constants===

Also, you don't want to act when your effort is really low and you are close to the target. There needs to be a minimum threshold before you start acting. This is rate_min. The higher you make rate_min, the more the controller acts like a bang-bang controller, where it waits till it's pretty late and then acts a bunch. about 1 order of magnitude below your max rate is probably a decent place to start for your rate min.

Also, you don't want to act when your effort is really low and you are close to the target. There needs to be a minimum threshold before you start acting. This is rate_min. The higher you make rate_min, the more the controller acts like a bang-bang controller, where it waits till it's pretty late and then acts a bunch. about 1 order of magnitude below your max rate is probably a decent place to start for your rate min.