Systems and methods of controlling instruments include first and second actuators configured to actuate a degree of freedom (DOF) in first and second directions using respective transmission mechanisms and a control unit. The control unit is configured to determine positions of the first and second actuators; determine an actuation command based on the positions of the first and second actuators, and a desired state of the DOF; determine respective actuation levels of the first and second actuators so as to maintain tensions in the transmission mechanisms above respective minimum tensions by: using a model based on the force or torque command, the minimum tensions, and the first and second actuator positions; and command actuation of the first and second actuators at the respective actuation levels. The model compensates for an external disturbance on the DOF and for dynamics of the first and second actuators.

A method is provided for absolute position determination of the end effector of a robotic device with a kinematic chain of movable components. At least one current torque or one value corresponding to the torque is measured on at least one movable component of the kinematic chain of the robotic device by a torque sensor arranged on the movable component. At least one torque is calculated on the basis of model data of the robotic device for the movable component. A difference between the measured torque and the calculated torque is determined. If the difference exceeds a prespecified threshold value, the at least one measured torque is used instead of the calculated torque to determine an absolute position of the end effector of the robotic device.

A robot control device able to accurately estimate an external force applied from a workpiece to a robot in a time-dependently changing manner. The robot control device includes a support force data acquisition section which acquires measurement data of a workpiece support force by the environment, the workpiece support force varying while the robot lifts the workpiece; a disturbance estimation section which estimates a disturbance value applied to the robot using state information of the robot; and a correction section which corrects, using the measurement data acquired by the support force data acquisition section, the disturbance value estimated by the disturbance estimation section or the state information inputted to the disturbance estimation section.

A method is provided for absolute position determination of the end effector of a robotic device with a kinematic chain of movable components. At least one current torque or one value corresponding to the torque is measured on at least one movable component of the kinematic chain of the robotic device by a torque sensor arranged on the movable component. At least one torque is calculated on the basis of model data of the robotic device for the movable component. A difference between the measured torque and the calculated torque is determined. If the difference exceeds a prespecified threshold value, the at least one measured torque is used instead of the calculated torque to determine an absolute position of the end effector of the robotic device.

Embodiments of the present disclosure relate to a method and apparatus for optimizing performance of a robotic cell. The robotic cell comprises at least one workstation and at least one robot. The method may comprise determining a factor and a corresponding workstation sensitive to the performance of the robotic cell by performing a sensitivity analysis on an initial cell layout for the robotic cell; and performing a performance optimization process on the corresponding workstation based on the determined factor to obtain an improved cell layout for the robotic cell. With embodiments of the present disclosure, it is possible to perform performance optimization of the robotic cell on the sensitive workstation regarding to the sensitive factor, and thus it may efficiently determine an improved cell layout which may achieve performance improvement.

A robot control device able to accurately estimate an external force applied from a workpiece to a robot in a time-dependently changing manner. The robot control device includes a support force data acquisition section which acquires measurement data of a workpiece support force by the environment, the workpiece support force varying while the robot lifts the workpiece; a disturbance estimation section which estimates a disturbance value applied to the robot using state information of the robot; and a correction section which corrects, using the measurement data acquired by the support force data acquisition section, the disturbance value estimated by the disturbance estimation section or the state information inputted to the disturbance estimation section.