Work vehicle magnetorheological fluid joystick systems operable in modified joystick stiffness modes

A work vehicle magnetorheological fluid (MRF) joystick system for usage onboard a work vehicle, the work vehicle MRF joystick system comprising:

• a joystick device, comprising:
• a base housing;
• a joystick movably mounted to the base housing;
• at least one resilient element within the base housing and exerting a bias force on the joystick urging return of the joystick to a center position when displaced therefrom;
• and
• a joystick position sensor configured to monitor movement of the joystick relative to the base housing;
• an MRF joystick resistance mechanism controllable to vary a joystick stiffness resisting movement of the joystick relative to the base housing in at least one degree of freedom;
• and
• a controller architecture coupled to the joystick position sensor and to the MRF joystick resistance mechanism, the controller architecture configured to command the MRF joystick stiffness mechanism to:
• permit return of the joystick to the center position solely under the influence of the bias force when the work vehicle MRF joystick system operates in a first joystick stiffness mode;
• and
• prevent return of the joystick to the center position solely under the influence of the bias force when the work vehicle MRF joystick system operates in a second joystick stiffness mode.