Abstract: An assembling method and an apparatus for carrying out the method capable of efficiently, reliably and easily detecting an insertion and fitting position, for easy automatic assembly. In case a rod-like workpiece is inserted into a hole in an object, an insertable range is determined based an amount of clearance between the workpiece and the hole, an amount of chamfering of the hole, etc. The insertable range is defined as within a range centered at a hole center position 3 cp and having a radium of r. A workpiece center position is indicated by 1 cp. While the workpiece is moved once throughout a search range (XL-XU) in the X-axis direction, it is moved in the Y-axis direction by an amount equal to or less than an insertable range amount 2r. As shown by a dotted line, the workpiece center 1 cp passes without fail through the insertable range during the motion throughout the search range (XL-XU, YL-YU).

Abstract: A spot welding system using a spot welding gun having a servomotor for driving welding tips capable of suppressing variation of pressing force due to influence of heat generated by welding current to obtain an uniform pressing force. A position control of the welding tips is performed based on motion commands r, position feedback amounts y to obtain a torque command (current command) &tgr; to drive the servomotor. A difference between the temperature T detected by a temperature sensor and an initial temperature T0 is multiplied by a coefficient A to obtain a pressing force compensation amount &agr;. In a pressing force control, the pressing force compensation amount &agr; is subtracted from the commanded pressing force to obtain temperature compensated command pressing force P′.

Abstract: A controller for a machine such as a robot and a machine tool having an electric motor as a driving source of the machine, capable of suppressing a natural vibration of the machine and/or an attachment attached to the machine. A frequency or a cycle of the natural vibration of an end effector of the robot as the attachment or the machine itself is determined and a coefficient of a filter for suppressing an amplitude of the natural vibration is altered in accordance with the measured frequency or cycle of the natural vibration. In the case of suppressing a natural vibration of the end effector attached to the robot, frequencies or cycles of natural vibrations of various end effectors in accordance with an operation status of the end effector are determined and stored, and the coefficient of the filter is set in accordance with the stored frequency or cycle of the natural vibration in accordance with the end effector attached to the robot and the operation status.

Abstract: An applied force Td is estimated by an observer. A gain A is multiplied by a value obtained by subtracting the estimated applied force Td from commanded force Fe. From this multiplied value, a product of a speed feedback amount and a gain Kv is subtracted to obtain a torque command. With this torque command Tc, a servo motor is driven. Since a feedback control of the applied force is performed, response is fast, and an applied force between welding tips and an object to be welded can be accurately controlled. Feedback control of an applied force, whose vibration is prevented, can be performed by adjusting the gains A and Kv.

Abstract: Bendings &Dgr;&agr;, &Dgr;&bgr;, and &Dgr;&thgr; are determined by the torques about the axes of coordinate systems disposed to respective joints and by spring constants. Parameters &agr;, &bgr;, and &thgr;0 are determined by adding an amount of twist to corrected D-H parameters &agr;s, &bgr;s, and &thgr;0s when twist is “0”. A rotational angle &thgr;′ (&thgr;st) is determined from a target position x by executing inverse kinematics using the parameters &agr;s, &bgr;s, and &thgr;0s (step S6). Further, a position x′ is determined from the rotational angle &thgr;′ by executing forward kinematics using the parameters &agr;, &bgr;, and &thgr;0, and the difference &Dgr;x between the target position x and the position x′ is determined. The difference is corrected, and a new target position x is set.

Abstract: An ultrasonic-motor control system includes an ultrasonic motor, a controller which starts the ultrasonic motor by changing a drive frequency of the ultrasonic motor from an initial drive frequency, a calculation device which calculates an initial drive frequency data based on a drive frequency at the commencement of rotation of the ultrasonic motor, and a setting device which sets the initial drive frequency based on the initial drive frequency data at a subsequent commencement of driving of the ultrasonic motor.

Abstract: A robot controller which controls a process controlled variable of an operational tool mounted on a robot in synchronism with the robot motion. The position of each axis of the robot is detected by a sensor such as a position detector. In a calculating section, motion variables such as position Pn, velocity vn and acceleration &agr;n of a tool center point (TCP) are detected from the respective positions of the robot axes. An ideal output (target value) of a sensor for detecting a controlled variable to be controlled in accordance with the motion state is determined in a calculating section. A sensor output is subtracted from the target value to determine a deviation. The deviation is multiplied by a proportional gain K to determine a manipulated variable. By using this manipulated variable, the process of an arc welding machine, sealing machine, or laser beam machine in which a tool is mounted on a distal end of a robot wrist is controlled.

Abstract: An applied force Td is estimated by an observer. A gain A is multiplied by a value obtained by subtracting the estimated applied force Td from commanded force Fc. From this multiplied value, product of a speed feedback amount and a gain Kv is subtracted to obtain a torque command. With this torque command Tc, servo motor (2) is driven. Since feedback control of applied force is performed, response is fast, and applied force can be accurately controlled. Feedback control of an applied force whose vibration is prevented can be performed by adjusting the gains A and Kv.

Abstract: A controller for a machine such as a robot and a machine tool having an electric motor as a driving source of the machine, capable of suppressing a natural vibration of the machine and/or an attachment attached to the machine. A frequency or a cycle of the natural vibration of an end effector of the robot as the attachment or the machine itself is determined and a coefficient of a filter for suppressing an amplitude of the natural vibration is altered in accordance with the measured frequency or cycle of the natural vibration. In the case of suppressing a natural vibration of the end effector attached to the robot, frequencies or cycles of natural vibrations of various end effectors in accordance with an operation status of the end effector are determined and stored, and the coefficient of the filter is set in accordance with the stored frequency or cycle of the natural vibration in accordance with the end effector attached to the robot and the operation status.

Abstract: A lens driving device for driving a focusing lens of a photographing lens for a camera is provided with a focusing ring that is rotated to move the focusing lens, an AF motor and an MF (manual focusing) ring. Each of the AF motor and the MF ring is connected to the focusing ring to rotate the same. The AF motor is driven to rotate. The MF ring is operable even when the AF motor is rotated. The device is further provided with a first detector that detects a driving amount of the focusing lens, a second detector that detects a driving speed of the AF motor, and a speed controller that controls a driving speed of the AF motor in accordance with detection outputs of the first and second detector.

Abstract: An industrial robot capable of preventing re-collision after colliding with an obstacle. Disturbing torque exerted on each servomotor for a robot axis is estimated by its associated disturbance estimating observer. When a hand attached to an end of a robot arm collides with an obstacle, an estimated value of disturbance given by a disturbance estimating observer exceeds a predetermined threshold, and the collision is detected. Then, each motor for driving a robot arm is drivingly controlled with a velocity command turned to “0”. Each motor for driving the robot hand is driven with torque having a predetermined magnitude (maximum magnitude) and the same sign as that of an estimated value of disturbing torque exerted on it, for a predetermined time, and then it is brought to an emergency stop. Thus, after colliding with an obstacle, the robot hand is driven in a direction such that it recedes from the obstacle.

Abstract: A method of and apparatus for detecting an abnormal load on a servo gun axis, capable of quickly detecting sticking of a welding tip to an object of welding before movement of a robot, without adversely affecting the object. A load applied to a servomotor for driving a welding tip of a welding gun is detected by an observer. An abnormal load signal is output when the estimated disturbance load deviates from a range defined by a reference &bgr; (&bgr;>0). A determination as to whether or not the estimated disturbance load is larger than the reference value +&bgr; is not made during a period of time from the start of a closing motion of the welding gun until the estimated disturbance load becomes smaller than a set value &agr;. When the welding tip is stuck to a workpiece, a negative estimated disturbance load smaller than −&bgr; is derived and an abnormal load Signal is outputted.

Abstract: A method of preventing interference of an industrial robot in which teaching of an operation program to the robot is easy and interference of the robot with an external cooperative apparatus can be easily avoided. If a current position of a reference point on the robot for detecting interference is outside a common area (S12) and a target position of the reference point is outside the common area (S18), a motion command is outputted to drive the robot. If the target position of the reference point is within the common area, it is determined that whether or not a movable part of the cooperative apparatus is within the common area, and if the movable part is outside the common area, an operation forbidding signal for the cooperative apparatus is turned on and the motion command is outputted to make the robot move. If the movable part of the cooperative apparatus is within the common area, the motion command is withheld till the movable part of the cooperative device moves out of the common area (S4, S5).

Abstract: A robot controller determines an abnormality in position, velocity or acceleration of an end effector or a rotational axis of a robot. The robot controller includes a servo CPU that periodically writes current position data in a shared RAM with a host CPU. The current position data is obtained from robot position sensors. Using the written position data, the host CPU periodically compares stored data corresponding to position, velocity or acceleration with the newly written data. When an abnormal motion is detected, the robot is immediately stopped.

Abstract: An automatic machine has a plurality of axes driven by servo motors. The controller for controlling this automatic machine confirms that a compulsory power disconnection mode is engaged, releases the brakes and starts power supply to servo amplifiers. At a prescribed time after power supply to said servo amplifiers has started, the power supply to the servo amplifiers is halted compulsorily. Alternatively, the power supply to the servo amplifiers is halted compulsorily at a prescribed time after power supply to the servo amplifiers has started and after initial movement commands have been input to the servo controllers.

Abstract: A robot which holds a workpiece (W) to be loaded with chuck (CH) moves on a programmed path from a tool center point to a point Q in response to a command. When a force sensor detects the contact between the distal end face of the workpiece (W) and a workpiece fixing surface (H), a loop gain of a servo control system is changed into a lower value. In consequence, the attitude of the workpiece (W) is corrected by means of a reaction force received from the workpiece fixing surface (H) and reaction forces from chucking members (CH1 to CH4), whereupon chucking is completed.

Abstract: A stitch machining method by an industrial robot capable of performing a teaching operation easily and the stitch machining accurately. Instead of teaching switchover points p1, P2, . . . for application and non-application of sealant in sealing as shown in FIG. 5a, a distance n1 of a machining section (where sealant is applied) and a distance n2 of a non-machining section are set to a robot controller as shown in FIG. 5b. The robot controller monitors a travel distance and switches from machining to non-machining and vice versa each time the robot travels the distance n1 and the distance n2, respectively, to thereby effect the stitch machining. As shown in FIGS. 5c and 5g, it is possible to ensure that a start and an end points of each block are positioned in the machining sections n1. Further, as shown in FIG. 5d, the stitch machining can be performed continuously for a plurality of blocks. As shown in FIG.

Abstract: A method of setting an accelerating/decelerating motion of a robot, in which a torque of the robot can be used efficiently without being saturated. In one section of motion, a moving ratio r representing a position which satisfies a condition such that a maximum torque is generated at a position where the maximum torque is needed, is successively and approximately obtained. First, a 0-th approximate solution (initial value) is assumed as .sub.i r.sub.0 =0, and then equations of motion are calculated at the position .sub.i r.sub.0 to obtain an acceleration so as to generate the maximum torque. The position such that the torque becomes maximal when the calculated acceleration is used is obtained as .sub.i r.sub.k+1. The difference .vertline..sub.i r.sub.k+1 -.sub.i r.sub.k .vertline. between the calculated .sub.i r.sub.k+1 and the previously calculated .sub.i r.sub.k is calculated, and it is checked whether or not the difference exceeds a preset very small value .epsilon.. If yes, the processing returns to S3.

Abstract: A control method for a servo system capable of adjusting softness to provide a robot with a soft floating function for each axis of a rectangular coordinate system. A force (Fx, Fy, Fz) acting on a tool center point in the rectangular coordinate system .SIGMA..sub.0 is obtained using a position error in the rectangular coordinate system .SIGMA..sub.0 and set parameters (Kx, Ky, Kz). The obtained force (Fx, Fy, Fz) is transformed into data (Fx.sup.(n+1), Fy.sup.(n+1), Fz.sup.(n+1)) in a tool coordinate system .SIGMA..sub.n+1, using posture data of the robot. Further, according to the Newton-Euler method, premising (Fx.sup.(n+1), Fy.sup.(n+1), Fz.sup.(n+1) =(fx.sup.(n+1), fy.sup.(n+1), fz.sup.(n+1), a torque Ti for each axis is calculated to obtain an input value Ei=Ti/(Kp.multidot.Kv) for a position loop.

Abstract: A method for properly compensating for a backlash between a servomotor and a machine moving part, such as a table, driven by the servomotor in a semi-closed-loop type control. In the semi-closed-loop type servo control, the force of a motor-driven table which acts on a motor is estimated by means of a disturbance observer, the side of the groove of a ball nut directly connected to the table, with which the ridge of the ball thread directly connected to the motor is in contact, is detected by the sign of the value of the estimated force, and the direction of backlash compensation is changed in accordance with the detected result.