A medical-robotic device that has a kinematic chain of movable components with an end effector at one end, with at least one force or torque sensor for the detection of at least one force or torque value on the kinematic chain. A control processor that controls the kinematic chain. An additional mechanical component is attached directly to the end effector or one of the movable components so that the additional component can transmit a force external to the device or a torque external to the device to the end effector or the movable component. The control processor determines the force external to the device or the torque external to the device on the basis of the at least one force or torque value detected, and controls the kinematic chain in dependence on the determined force external to the device or the determined torque external to the device, in order to increase the accuracy of the medical-robotic device.