A device for acquiring a position and orientation of an end effector of a robot is provided. The robot has a robot arm with axes coupled to one another by joints. The end effector is arranged on an end of the robot arm, optical markers are arranged on first and second axes, and a number of joints between the end effector and the first axis is lower than a number of joints between the end effector and the second axis. An optical sensor acquires image data of the optical markers. A storage device stores a kinematic model of the robot arm. An evaluation device, in a first case, determines a first position of a first optical marker and the position and orientation of the end effector and, in a second case, a second position of a second optical marker and the position and orientation of the end effector.

A robot system includes a robot that self-travels along a traveling shaft and is provided with a position detection sensor at a distal end, a support member that has a plurality of reference positions juxtaposed and supports a workpiece, a plurality of calibration members that are juxtaposed along the traveling shaft, and a control device, in which the calibration members each have a calibration position, and the control device is configured to cause the robot to move by a predetermined first distance along the traveling shaft, calibrate position coordinates of the robot based on position coordinates of the calibration positions detected by the position detection sensor, and subsequently calibrate position coordinates of the workpiece based on position coordinates of the reference positions detected by the position detection sensor.

A direct pose feedback (DPF) control method applied to a DPF controlled machine is provided. The DPF control method includes a pose compensation control in addition to the position feedback control. The pose compensation control includes an initiation step, a reference system step, an actual pose calculation step and a position compensation step. The sum of the primary driving value and the compensation driving value is output to the driver of each of the motors. The advantage of the DPF control method is that the existing real-time position control loop in the controller can remain unchanged, while the pose compensation control is added to eliminate tool pose error resulted from geometric errors in the machine. The DPF controlled machine uses a pose measuring mechanism to measure the actual pose of the tool and to compensate the tool pose error. Hence, the DPF controlled machine is free of geometric errors.

A positioning system using a robot, capable of eliminating an error factor of the robot such as thermal expansion or backlash can be eliminated, and carrying out positioning of the robot with accuracy higher than inherent positioning accuracy of the robot. The positioning system has a robot with a movable arm, visual feature portions provided to a robot hand, and vision sensors positioned at a fixed position outside the robot and configured to capture the feature portions. The hand is configured to grip an object on which the feature portions are formed, and the vision sensors are positioned and configured to capture the respective feature portions.

The present invention relates to methods and devices for compensating for a thermally induced change in position on a numerically controlled machine tool, wherein: a characteristic map describing the thermoelastic behaviour of the machine tool is provided to a control system of the machine tool; one or more temperature values are determined by means of one or more temperature sensors on the machine tool; one or more compensation parameters are determined on the control system of the machine tool on the basis of the one or more temperature values determined and of the characteristic map provided; and wherein a temperature-dependent change in position on the machine tool is performed according to the one or more compensation values determined. According to the invention, the characteristic map provided is adjusted or updated by means of a neural network running on a computer.

A robot device includes an arm mechanism that includes links and joints. A hand is mounted to a tip of the arm. A motor driver drives motors of the joints. A processor outputs, to the motor driver, a command value for moving a reference point of the hand to a target position. A storage device stores a first thermal displacement amount temporal variation representing a variation with respect to a continuous operation time period in a thermal displacement amount by which the hand reference point is displaced from a cool position to a heat balance position due to heat generation accompanying operation of the arm mechanism, and a second thermal displacement amount temporal variation representing a variation with respect to a continuous stopped time period in a thermal displacement amount by which the hand reference point returns from the heat balance position to the cool position accompanying stopping of operation of the arm mechanism. The processor refers to the first and second thermal displacement amount temporal variations to estimate a thermal displacement amount of the hand reference point based on the continuous operation time period and continuous stopped time period of the arm mechanism, and corrects the target position based on the estimated thermal displacement amount.

A robot control method of controlling motion of a robot arm by using a servo motor includes adding d-axis electric current to a motor electric current command (steps 15-6, 15-8) if external temperature is less than or equal to a predetermined value (step 15-3), and if an absolute value of the motor electric current command is less than or equal to a predetermined value (step 15-4), and if a value of detected overload is less than or equal to a predetermined value (step 15-5).

The present disclosure is directed toward a method that includes logging offset data of a machine over a period of operational time having varying thermal conditions, comparing the logged offset data against a thermal model, estimating offsets for the machine based on the comparing, and adjusting offsets of the machine during operation.

A direct pose feedback (DPF) control method applied to a DPF controlled machine is provided. The DPF control method includes a pose compensation control in addition to the position feedback control. The pose compensation control includes an initiation step, a reference system step, an actual pose calculation step and a position compensation step. The sum of the primary driving value and the compensation driving value is output to the driver of each of the motors. The advantage of the DPF control method is that the existing real-time position control loop in the controller can remain unchanged, while the pose compensation control is added to eliminate tool pose error resulted from geometric errors in the machine. The DPF controlled machine uses a pose measuring mechanism to measure the actual pose of the tool and to compensate the tool pose error. Hence, the DPF controlled machine is free of geometric errors.

A robot device includes an arm mechanism that includes links and joints. A hand is mounted to a tip of the arm. A motor driver drives motors of the joints. A processor outputs, to the motor driver, a command value for moving a reference point of the hand to a target position. A storage device stores a first thermal displacement amount temporal variation representing a variation with respect to a continuous operation time period in a thermal displacement amount by which the hand reference point is displaced from a cool position to a heat balance position due to heat generation accompanying operation of the arm mechanism, and a second thermal displacement amount temporal variation representing a variation with respect to a continuous stopped time period in a thermal displacement amount by which the hand reference point returns from the heat balance position to the cool position accompanying stopping of operation of the arm mechanism. The processor refers to the first and second thermal displacement amount temporal variations to estimate a thermal displacement amount of the hand reference point based on the continuous operation time period and continuous stopped time period of the arm mechanism, and corrects the target position based on the estimated thermal displacement amount.