摘要:
A method of obtaining a very robust adaptive PI control method irrespective of fluctuation of parameters of a control object, wherein (speed command r-actual speed y) is used as a state variable Suf. Estimated values J*, A*, Gr*, and C* of inertia, coefficient of dynamic friction, gravitational disturbance depending on a robot angle, and Coulomb's friction, respectively, are obtained and a torque command .tau. is obtained in accordance with the following equation so as to cancel an error between each of the estimated values and its actual value to zero. .tau.=K2.multidot.Suf+(K1/s).multidot.Suf+J*.multidot.r'+A*.multidot.y+Gr*.multidot.sin .theta.+Cf*+.tau.1. The first and second terms of the right side of the above equation are identical with a torque command obtained by the PI control. Furthermore, r' represents an acceleration of command; .theta. represents a rotational angle of a robot arm; and .tau.1 represents a switching input corresponding to miscellaneous disturbance. As an error between each of the estimated values and its actual value becomes zero, a relationship of speed command r=actual speed y is obtained and therefore an adaptive PI control of a transfer function "1" is obtained.
摘要:
A control method for a servomotor which is controlled by a control system with a position control loop and a speed control loop, such that a degree of flexibility specified on working coordinates, on which the servomotor is situated, is converted into servo gains Kp and Kv for individual axes of the servomotor, and the servomotor is driven according to the converted servo gains Kp and Kv, whereby the degree of flexibility can be set on the working coordinates, and a driven body can be moved manually.
摘要:
A robotic arm is driven by a servomotor which is controlled through position and speed control loops. The position and speed control loops are adaptable in response to a flexible position control. Upon receipt of a flexible control command, a position gain and a proportional gain of the speed control loop are lowered in accordance with a set degree of flexibility. The output of an integrator of the speed control loop is also limited to a set clamp value. As a result, a torque command for controlling the servomotor never achieves an expressly large value even if a position deviation increases. In case an obstacle is placed in the transfer path of the robotic arm, the arm can be moved by human power to avoid the obstacle.
摘要:
A collision detecting method for quickly securely detecting a collision between a driven body driven by a servomotor and an obstacle by using an observer, thereby preventing machine components from being damaged by the collision. An estimated distrubance torque (y) is obtained in accordance with a torque command (I) and an actual motor speed (.theta.) by means of the observer (50) formed of blocks (51 to 54) having transfer functions (Kt/J, K3, K4/S, 1/S), which depend individually on a torque constant, inertia, and parameters corresponding thereto, and a multiplier (61) having a transfer function (J.multidot.A) equivalent to the product of the inertia and a unit system conversion constant. The drive of the servomotor is stopped before any of the components of the machine is broken, in response to an alarm delivered from a comparator (62) when the estimated disturbance torque exceeds a threshold value (Ts) which is set at a value smaller than servomotor output torques corresponding to the breaking limits of the machine components.
摘要:
A collision detecting method for quickly securely detecting a collision between a driven body driven by a servomotor and an obstacle by using an observer, thereby preventing machine components from be damaged by the collision. An estimated disturbance torque (y) is obtained in accordance with a torque command (I) and an actual motor speed (.theta.) by means of the observer (50) formed of blocks (S1 to 54) having transfer functions (Kt/J, K3, K4/S, 1/S), which depend individually on a torque constant, inertia, and parameters corresponding thereto, and a multiplier (61) having a transfer function (J.multidot.A) equivalent to the product of the inertia and a unit system conversion constant. The drive of the servomotor is stopped before any of the components of the machine is broken, in response to an alarm delivered from a comparator (62) when the estimated disturbance torque exceeds a threshold value (Ts) which is set at a value smaller than servomotor output torques corresponding to the breaking limits of the machine components.
摘要:
A control device for controlling the motion of a movable part in a machine while suppressing vibration generated in the movable part. The control device includes a state-variable estimating section for estimating a state variable of a controlled system in the machine and outputting an estimated state variable; a reference model for outputting an ideal controlled variable for the controlled system; a compensator for calculating a compensation value for correcting a control input for the controlled system, based on a difference between the estimated state variable and the ideal controlled variable; and a feedback control section for determining the control input, based on a deviation between a desired command value and one of the estimated state variable and the ideal controlled variable. A corrected control input obtained by correcting the control input determined through the feedback control section by using the compensation value calculated through the compensator is input to the controlled system as well as to the state-variable estimating section and the reference model.
摘要:
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.
摘要:
A control method capable of preventing vibration of a control object and making a band sufficiently high in controlling a robot or a machine tool in semi-closed loop. A torque command u" is obtained by executing a feedback-control of the servomotor using the position and speed of a servomotor in the same manner as in the conventional method. A displacement amount d1 between the motor position and the position of the control object and a displacement speed d2 are estimated by an observer. A corrected torque command u is determined by subtracting, from the torque command u", values obtained by multiplying the displacement amount d1 and the displacement speed d2 by the adjustable gains (.alpha.-KpK1) and (.beta.-K1), respectively. The servomotor is driven based on the corrected torque command u thus obtained. There can be obtained effects equivalent to those that would be obtained when a feedback-control is performed using the position and speed of the control object. The adjustment values .alpha. and .beta. are so adjusted as to stabilize a response from the corrected torque command to the control object.
摘要:
There is provided a servo controller for a spot welding gun for controlling a pressurizing force, applied by a pair of mutually-opposing gun chips, on an object to be welded, including at least one movable gun chip, which is held between the pair of gun chips, by causing a drive source of the movable gun chip to drive the movable gun chip in a direction in order to pressurize the object to be welded. The servo controller includes a feedback control section for calculating a difference value (Fc−F) between an obtained pressurizing-force value F and a required pressurizing-force value Fc, and a feedforward control section for adding a correcting command value, obtained from a position command value or a speed command value for the drive source, to the difference value (Fc−F).
摘要翻译:提供了一种用于点焊枪的伺服控制器,用于控制由一对相互相对的枪芯施加在被焊接物体上的加压力,该加压力包括至少一个可动枪芯片,该至少一个可动枪芯片保持在一对 通过使可动枪芯片的驱动源沿一个方向驱动可动枪芯片,以加压待焊接的物体,从而使枪片切割。 伺服控制器包括反馈控制部分,用于计算所获得的加压力值F和所需的加压力值F C之间的差值(F < 以及前馈控制部分,用于将从驱动源的位置命令值或速度指令值获得的校正命令值添加到差值(F SUB C -F)。
摘要:
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 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 α. A pressing force d estimated by an observer is subtracted from the compensated command pressing force p′ and an obtained difference is multiplied by a constant K2 to obtain a torque command (current command) τ for driving the servomotor to press the objects by the welding tips. Since the commanded pressing force is compensated in accordance with the temperature, a constant and stable pressing force is produced without influence of the temperature variation.