Abstract: There is provided a method and an apparatus for controlling a robot arm. In this control scheme, a position error indicating a deviation between a command position, which is a control target position, and a current position, which is a position where the arm of the robot is currently located, is acquired. When the acquired position error exceeds a threshold, a new corrected command position between the current position and the command position is set. After the arm of the robot is moved to the corrected command position, a new corrected command position reset between the corrected command position serving as a new current position and the command position. Reconfiguration of a corrected command position is iterated until a current position of the robot arm becomes equal to the command position so that movement of the robot arm is achieved from the current position to the command position.

Abstract: There is provided a robot control apparatus that controls a vertical articulated robot and is suitable for direct teaching. In the apparatus, an axis setting section sets operation axes and control axes from among the axes subjected to angle control, when performing the direct teaching of changing a position of the arm tip, while retaining a posture thereof at a target posture. The operation axes can be dominant factors when determining the position of the arm tip and are allowed to freely move according to an external force, and the control axes can be dominant factors when determining the posture of the arm tip and are controlled by an angle control section. When performing the direct teaching, the angle control section receives an input of current angles of the operation axes and the target posture to calculate command angles of the respective control axes according to inverse kinematics calculation.

Abstract: There is provided a robot control apparatus that controls a vertical articulated robot and is suitable for direct teaching. In the apparatus, an axis setting section sets operation axes and control axes from among the axes subjected to angle control, when performing the direct teaching of changing a position of the arm tip, while retaining a posture thereof at a target posture. The operation axes can be dominant factors when determining the position of the arm tip and are allowed to freely move according to an external force, and the control axes can be dominant factors when determining the posture of the arm tip and are controlled by an angle control section. When performing the direct teaching, the angle control section receives an input of current angles of the operation axes and the target posture to calculate command angles of the respective control axes according to inverse kinematics calculation.

Abstract: A method and apparatus for controlling a robot is provided. In this robot, direct teaching can be performed while updating a position command on the basis of an applied external force. In the method and apparatus, a proximity region is set inside a boundary of an operation-allowed range of the robot, the proximity region being indicative of a proximity of the boundary. Stored is an external force applied when a monitoring point provided in the robot reaches the proximity region as a reference external force. And performed is comparing the reference external force with a current external force when a current position of the monitoring point is in the proximity region, to thereby determine a direction that facilitates movement away from the proximity region.

Abstract: A robot has a vertical 6-axis articulated arm having an offset arm having a fifth axis and length link, and mutually linking fourth and sixth axes. The fourth and sixth axes shaft centers are parallel. The articulated arm has a head portion designated as a control point. A position and an orientation targeted to the control point is processed by an inverse transform to calculate angles of the axes. A provisional target position of the sixth axis is obtained by subtracting the link length from a target position of the sixth axis. The link length to the provisional target position is given zero to perform the inverse transform process. Processed results are evaluated. Until a difference between a calculated sixth-axis angles and provisionally decided sixth-axis angles becomes equal to or less than a predetermined value, processes started from the angle provisional decision of the sixth axis are repeatedly performed.

Abstract: In an eccentricity error correction method for an angle detector, an output shaft angle is determined in at least three measurement positions. A difference between an arm angle value at each measurement position and the output shaft angle detected at each measurement position is determined as an eccentricity error. An error curve indicates a relationship between the arm angle value and the eccentricity error, and is determined as a function of the arm angle value by approximating the eccentricity error at each measurement position with a sine wave of which a single cycle is a single rotation of the arm. A correction formula that associates the output shaft angle and the arm angle value is determined using the error curve. A correction value corresponds to the detected output shaft angle, and is determined based on the correction formula and correcting the eccentricity error when the arm is rotated.

Abstract: There is provided a robot control apparatus that controls a vertical articulated robot and is suitable for direct teaching. In the apparatus, an axis setting section sets operation axes and control axes from among the axes subjected to angle control, when performing the direct teaching of changing a position of the arm tip, while retaining a posture thereof at a target posture. The operation axes can be dominant factors when determining the position of the arm tip and are allowed to freely move according to an external force, and the control axes can be dominant factors when determining the posture of the arm tip and are controlled by an angle control section. When performing the direct teaching, the angle control section receives an input of current angles of the operation axes and the target posture to calculate command angles of the respective control axes according to inverse kinematics calculation.

Abstract: A deflection angle detection device includes an input shaft encoder, a disk attached to an output shaft of a speed reducer, an output shaft encoder having detection elements disposed at mutually different positions with respect to the disk to detect angular positions of the disk. A basic angular position of the output shaft is calculated based on an angular position of the input shaft detected by the input shaft encoder, a first, a second, and a third angular positions of the output shaft are calculated based on the angular positions of the disk detected by a plurality of detecting elements, and the deflection angle of the output shaft is calculated based on a first, a second, and a third differences, which are differences between the basic angular position and the first, the second, and the third angular positions, respectively, and positions of the detection elements with respect to the disk.

Abstract: In an industrial robot, correction is made for change in position and attitude of an arm distal end due to mechanical deflection of the robot. In the robot, a moment applied to the first axis in its non-rotation direction opposite to its rotation direction is calculated from a load torque applied to the second axis in its rotation direction, a moment due to a second-axis-side self-weight, and a ratio of a distance between the rotation centers of the first and second axes, to a distance between the rotation centers of the second axis and a tool. A deflection amount indicating an angle of the first axis tilting in the non-rotation direction is calculated from the moment applied to the first axis and the rigidity of the first axis in the non-rotation direction. A control value is corrected based on the deflection amount to control the robot.

Abstract: A method and apparatus for controlling a robot is provided. In this robot, direct teaching can be performed while updating a position command on the basis of an applied external force. In the method and apparatus, a proximity region is set inside a boundary of an operation-allowed range of the robot, the proximity region being indicative of a proximity of the boundary. Stored is an external force applied when a monitoring point provided in the robot reaches the proximity region as a reference external force. And performed is comparing the reference external force with a current external force when a current position of the monitoring point is in the proximity region, to thereby determine a direction that facilitates movement away from the proximity region.

Abstract: There is provided a method and an apparatus for controlling a robot arm. In this control scheme, a position error indicating a deviation between a command position, which is a control target position, and a current position, which is a position where the arm of the robot is currently located, is acquired. When the acquired position error exceeds a threshold, a new corrected command position between the current position and the command position is set. After the arm of the robot is moved to the corrected command position, a new corrected command position reset between the corrected command position serving as a new current position and the command position. Reconfiguration of a corrected command position is iterated until a current position of the robot arm becomes equal to the command position so that movement of the robot arm is achieved from the current position to the command position.

Abstract: A robot has a vertical 6-axis articulated arm having an offset arm having a fifth axis and length link, and mutually linking fourth and sixth axes. The fourth and sixth axes shaft centers are parallel. The articulated arm has a head portion designated as a control point. A position and an orientation targeted to the control point is processed by an inverse transform to calculate angles of the axes. A provisional target position of the sixth axis is obtained by subtracting the link length from a target position of the sixth axis. The link length to the provisional target position is given zero to perform the inverse transform process. Processed results are evaluated. Until a difference between a calculated sixth-axis angles and provisionally decided sixth-axis angles becomes equal to or less than a predetermined value, processes started from the angle provisional decision of the sixth axis are repeatedly performed.

Abstract: In an eccentricity error correction method for an angle detector, an output shaft angle is determined in at least three measurement positions. A difference between an arm angle value at each measurement position and the output shaft angle detected at each measurement position is determined as an eccentricity error. An error curve indicates a relationship between the arm angle value and the eccentricity error, and is determined as a function of the arm angle value by approximating the eccentricity error at each measurement position with a sine wave of which a single cycle is a single rotation of the arm. A correction formula that associates the output shaft angle and the arm angle value is determined using the error curve. A correction value corresponds to the detected output shaft angle, and is determined based on the correction formula and correcting the eccentricity error when the arm is rotated.

Abstract: In an industrial robot, correction is made for change in position and attitude of an arm distal end due to mechanical deflection of the robot. In the robot, a moment applied to the first axis in its non-rotation direction opposite to its rotation direction is calculated from a load torque applied to the second axis in its rotation direction, a moment due to a second-axis-side self-weight, and a ratio of a distance between the rotation centers of the first and second axes, to a distance between the rotation centers of the second axis and a tool. A deflection amount indicating an angle of the first axis tilting in the non-rotation direction is calculated from the moment applied to the first axis and the rigidity of the first axis in the non-rotation direction. A control value is corrected based on the deflection amount to control the robot.

Abstract: A deflection angle detection device includes an input shaft encoder, a disk attached to an output shaft of a speed reducer, an output shaft encoder having detection elements disposed at mutually different positions with respect to the disk to detect angular positions of the disk. A basic angular position of the output shaft is calculated based on an angular position of the input shaft detected by the input shaft encoder, a first, a second, and a third angular positions of the output shaft are calculated based on the angular positions of the disk detected by a plurality of detecting elements, and the deflection angle of the output shaft is calculated based on a first, a second, and a third differences, which are differences between the basic angular position and the first, the second, and the third angular positions, respectively, and positions of the detection elements with respect to the disk.