A servo controlled system is disclosed for providing simulated feel equivalent to that of traditional mechanical hand controllers using servomotors. Position and force sensor signals are processed and used in a feedback loop that controls the motor mechanically connected to the stick. The overall feedback loop is comprised of a low-level motor feedback loop, and high-level force feel loop. The two loops have associated performance parameters that can be specified independently. The high-level feel force loop is comprised of a static and dynamic performance components. Static and dynamic performance components can be specified independently. The system allows variable and/or additional force cues to be specified externally to the system and felt by the operator. The system also allows external signal to backdrive the stick to follow a specified motion. The control framework permits the electronic coupling of the motion and applied forces of pilot and co-pilots in a dual arrangement while retaining the above-mentioned features. It also allows asymmetric force feel gradients to be implemented for each stick, or for a stick relative to a second one. A zero breakout or detent can be provided at the stick null displacement. For cross-coupled sticks, the detent can be shared as in a mechanically cross-coupled system, implemented independently on each stick, or any combination of these two. The control framework also provides the simulation of mechanical compliance in the cross-coupling of the two sticks in case of a jam or of force fight between the pilots, and automatic de-coupling of the sticks.
APPARATUS FOR CONTROLLING A JOYSTICK HAVING FORCE-FEEDBACK