forceposition

Force-position control is a robotics control paradigm that coordinates the regulation of an end-effector’s position with the regulation of contact forces during manipulation tasks. It addresses the need for safe, accurate, and compliant interaction with uncertain or delicate environments, such as assembling parts, surface finishing, or robot-assisted surgery.

There are several implementations of force-position control. Hybrid force/position control assigns separate control tasks to motion and contact axes: motion axes use a position or velocity controller, while contact axes use a force controller to regulate contact pressures. Impedance control, by contrast, makes the end-effector behave like a virtual mass-spring-damper system, so external forces result in compliant motions. Admittance control uses measured contact forces to command motion through a virtual mechanical admittance. Together, these approaches enable a robot to respond smoothly to contact and to maintain desired force levels while achieving the target pose.

Implementation relies on sensors such as force/torque sensors or tactile sensors and precise position sensing from joint encoders. Stability and performance depend on accurate modeling of contact dynamics, proper tuning of control parameters, and sometimes explicit stability analyses. Common challenges include sensor noise, friction, modeling uncertainty, and complex contact topology, which can lead to instability if not carefully managed.

Applications span industrial manipulation, assembly, polishing and deburring, hand-guiding and haptic devices, and surgical robotics. The field has evolved through decades of research in impedance, admittance, and hybrid control, forming a core set of techniques for safe and effective robot–environment interaction.