Fanuc Corporation

Tetsuo Hishikawa

Kentaro Fujibayashi

Takashi Idei

Yasushi Onishi

Keisuke Tsujikawa

Noboru Hirose

Takehiro Yamaguchi

Yusaku Yamada

Initial speeds in the move commands for respective control axes at servo-on are determined according to parameter setting, or the comparative relationship or difference in speed among the actual speeds of the control axes so that difference in position between the control axes does not increase as the move commands are executed after the servo-on. The actual speeds of the control axes are set as initial speeds in the move commands, and a target axis is specified on the basis of the comparative relationship among their actual speeds and the other control axes are accelerated or decelerated at the acceleration or deceleration rate specified in the move commands to attain the position and speed of the target axis, so that differences in position and speed among the control axes are gradually decreased as the move commands are executed after the servo-on, thereby preventing abrupt speed changes and suppressing mechanical shocks.

Numerical controller controlling acceleration and deceleration of respective control axes up to command speeds

A synchronous controller capable of gently changing a synchronous multiplying factor and setting the gentleness of changing of the synchronous multiplying factor without shocking a machine. A block for gently changing the synchronous multiplying factor is added between blocks before and after the changing of the synchronous multiplying factor. Synchronous multiplying factors a and b before and after changing of the synchronous multiplying factor designated in the added block, a motion amount p of master axis, a motion amount of a slave axis, and a residual motion amount v of the master axis after the completion of changing the synchronous multiplying factor (or a preliminary motion amount u of the master axis from the start of motion of the block concerned to a position for the start of changing of the synchronous multiplying factor) are read out. A gradient of changing the synchronous multiplying factor and the preliminary motion amount u (or the residual motion amount v) are obtained based on these data. The slave axis is controlled based on the motion amounts u and v and the gradient of changing the synchronous multiplying factor. The synchronous multiplying factor is changed so gently that the machine cannot be shocked. The synchronous multiplying factor gradient can be settled depending on the designated data p, q and v (or u).

Synchronous controller

A numerical controller is capable of foreseeing the occurrence of interference during operation of a machine and securely preventing the interference. An advanced position calculating section determines advanced time for the next interference check, based on an end time point of an interference check by an interference checking device and the sum of a time required for the interference check, a time required for communication, a time required for decelerating and stopping a movable part, and a predetermined float. If an interference checking device detects interference, the interference checking device delivers an axis stop signal the movable part.

Numerical controller

A conveyer for transporting a box and a conveyer for transporting a bottle are driven along a follow-up target axis and a follow-up axis, respectively. The follow-up axis is accelerated from a synchronization start position, and, when the follow-up axis velocity catches up with the conveyer, performs the constant velocity operation. An advanced operation, performed by an asynchronous axis (moving the bottle closer to the box), is started before synchronization completes, and is completed when synchronization completes, then immediately an operation by a synchronous axis (follow-up target axis or follow-up axis) is started (insertion operation). The point of time when the advanced operation is started is determined by processing of the numerical controller, as a point of time when the time required for the follow-up axis in the current status to reach the synchronization completion status becomes the same as the time required for the advanced operation (preset).

Numerical controller and synchronous control method using numerical controller

A servomotor in a numerical controller is controlled by automatically switching to either pressure control or position control in association with the command which is smaller from among a command obtained by performing pressure feedback control and a command obtained by performing position feedback control. When switched to pressure control while moving according to a movement command, the output of the movement command is terminated halfway, and the command in the next block is executed, and pressure control of the next command is immediately started. As a result, a wasteful time is eliminated, and a cycle time of the operation can be shortened.

When a servomotor (control axis) is coasting and rotating in a servo-off state in which no current is applied to the servomotor, this servo-off state is switched over to a servo-on state in which current is applied to the servomotor, and a position control and a speed control are started. An actual speed in servo-on state is obtained in speed obtaining means by a position/speed detector. Position command means obtains a command movement amount using the actual speed as an initial speed. A position deviation amount corresponding to the actual speed is calculated, a command movement amount, a position deviation amount, and a position deviation amount remaining in a position deviation counter in servo-on state with the sign thereof reversed are added to each other as a command amount to the position deviation counter.

A die cushion controller uses position control to position die cushion members for placement of a metal sheet. A pressing process starts and the upper die is lowered. When a position detector detects a position at which the upper die touches the sheet metal, the die cushion controller switches over from position control to pressure control and applies a preset pressure to the sheet metal. When the position detector detects that the upper die has risen to a preset position, the die cushion controller clears the positional deviation accumulated in position control to zero, then moves the die cushion members to preset positions and holds them there.

Die cushion controller

An 'interval' in which the synchronization status between the movable axes subject to synchronous control is monitored, an equation between the movable axes in the 'interval', and an &#x2018;allowable displacement&#x2019; for the positional relationship obtained with this equation and the actual positional relationship are set in advance. The &#x2018;start condition&#x2019; and &#x2018;termination condition&#x2019; for synchronous status verification processing are set with the master position and the like. When the start condition for synchronous status verification processing is satisfied, it is detected whether or not the actual position and the position obtained with the equation are within the range of the allowable displacement based on the position of the movable axes. If not within the range of the allowable displacement, operation set as &#x2018;operation to be executed when the allowable displacement is exceeded&#x2019; is executed.

Synchronous control device

A method of and apparatus for synchronous control of a leading element and a follower element in which synchronism is started smoothly and a mechanical shock at the start of synchronism is reduced. When the follower element is started to move to be synchronized with the leading element, motion of the follower element is started before the follower element reaches a start position of the synchronism, and brought into synchronism with the leading element at the start position of synchronism. A positional relationship between the leading element and the follower element in synchronism, and a start position for starting the synchronism of the follower element and the leading element is set. An acceleration control of the follower element is performed between a motion start position preceding the start position of the synchronism and the start position of the synchronism. A position control of the follower element is performed based on position data of the leading element and the set positional relationship after the follower element reaches the start position of the synchronism.

Method of and apparatus for synchronous control

A synchronous controller capable of easily controlling a slave axis in synchronism with a master axis performing a composite motion of a plurality of axes. Motion commands for two axes X, Y constituting the master axis are subject to interpolation/distribution and acceleration/deceleration processing, to determine distribution motion amounts, and the determined amounts of motion of the two axes X, Y constituting the master axis for every interpolation period are combined to determine an amount of motion M of the master axis, from which is determined an amount of motion of the slave axis for every interpolation/distribution period. The determined amounts of motion of the X, Y and slave axes are output to respective servo control means, thus driving the respective axes. In case the master axis is constituted by a means driven by external X and Y axes, amounts of motion of the external X and Y axes for every predetermined period are detected by detectors, and used, instead of the distribution motion amount, to determine an amount of motion M of the master axis from which an amount of motion of the slave axis is determined to drive the slave axis.

A reference variable having a linear relationship with the angular position of a master axis is set, and a correspondence between this reference variable and the displacement of a slave axis is stored in a data table. One execution stage is specified by setting a starting reference variable and an ending reference variable from this data table. A desired sequence is assigned to a plurality of execution stages thus specified. The reference variable corresponding to the angular position of the master axis is determined, slave axis displacement data corresponding to the reference variable is read out, and the slave axis is positioned in accordance with the position of the master axis on the basis of this displacement data.

Synchronization control method and synchronization control device

An acceleration/deceleration method capable of synchronizing two axes in velocity and also in position is disclosed. A follower axis X continues to be accelerated after a velocity Vx of the follower axis X reaches a target velocity Vy of an objective axis Y and the acceleration is changed over to a deceleration to achieve the target velocity Vy. The time for changing over the acceleration to the deceleration is determined so that the motion amount of the position Px of the follower axis X in excess of the motion amount of the position Py of the objective axis Y is equal to the sum of the displaced motion amount in the acceleration motion and an initial positional difference. Thus, the position and velocity of the follower axis X coincide with the position and velocity of the objective axis Y to achieve complete synchronism of the two axes in the case where there is a positional difference and a velocity difference between the two axes.

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Yamanashi, Japan

Tetsuo Hishikawa