Certain examples described herein provide a method of controlling a robotic device including a body, an end effector coupled to the body by one or more joints and a propulsion system to drive the one or more joints to control a state of the robotic device. Example methods include applying impedance control to the robotic device; determining a reference trajectory of the end effector; detecting an applied external force and/or torque acting on the robotic device causing a departure from the reference trajectory; calculating an adjustment to be applied to one or more of the one or more joints to compensate for the detected applied external force and/or torque; and using the calculated adjustment to control the one or more joints to actuate the end effector and recover the reference trajectory of the end effector.

A machine tool comprises: a servomotor feeding a workpiece or a tool; a motor control section controlling the servomotor; and a processor connected to the motor control section, in a parameter adjustment mode while rotating a load by the servomotor with a given speed command issued to the motor control section under a condition where torque is limited, the processor calculating load inertia based on the torque and an angular acceleration of the servomotor that is obtained based on an output from the servomotor, calculating a parameter based on the load inertia, and adjusting a control parameter set to the motor control section based on the parameter.

A machine tool comprises: a servomotor feeding a workpiece or a tool; a motor control section controlling the servomotor; and a processor connected to the motor control section, in a parameter adjustment mode while rotating a load by the servomotor with a given speed command issued to the motor control section under a condition where torque is limited, the processor calculating load inertia based on the torque and an angular acceleration of the servomotor that is obtained based on an output from the servomotor, calculating a parameter based on the load inertia, and adjusting a control parameter set to the motor control section based on the parameter.