Correct and Accurate Joystick Axis Control Inputs are essential to the proper operation of your cockpit. This is how i get what i want out of my controls.  All inputs with the exception of the Rudder Pedals are made thru Leo Bodnar's BU0836 and BU0836X Joystick Controllers.
1. Any Axis, that is any control input you make over a range, needs to be interpreted and relayed to your aircraft as a value it can understand and work with.  This is accomplished using a variable resistor called a potentiometer. Whatever kind of joystick or Yoke or TQ you have, it will control the AXES Inputs using some kind of 'pot'.  In my cockpit, these are the Inputs using this method.   Capt and F/O Yokes for Roll & Pitch, Capt and F/O Steering Tillers, Both Sets of Rudder Pedals (inc.Toe Brakes), TQ - Seperate Throttles Per Engine - Seperate Reversers Per Engine - Flaps and Spoiler.  Total 18 axes.
2. The 'pots' are connected to a controller, in my case the BU0836 and the BU0836X boards. Joystick Control Boards are seen by your operating system as a joystick which can then have the axes 'assigned' and configured.  Normally they are 10bit resolution, but the BU0836 cards i use are all 12bit resolution giving me a whopping 4096 position reports over the range of the 'pot' instead of the normal 1024.   This greatly increases the accuracy of the input.
3. It is my preference to disable the Joysticks in FS and Use the AXIS ASSIGNMENT and JOYSTICK CALIBRATION pages in FSUIPC. I find this a much more accurate setup method than using the FS internal Joystick Calibration and Assignment routines.  FSUIPC gives you full control of your axis, cleans and adjusts it to suit.
4. Once processed thru FSUIPC, the control is then passed into your aircraft as the aileron,elevator or whatever you have assigned it to.