Abstract:
A motion controller and a method of controlling the motion of a plurality of axes which prevents a discontinuous position command being generated to a follower axis. A follower mode transfer function circuit or routine generates a position command in response to a master axis position. This function can be in the form of electronic gearing or camming. A bias latch is utilized to offset any change in position resulting from a change in mode, such as changing from electronic gearing to electronic camming, changing cam profiles or gearing ratios, or changing the master axis. The latch is summed with the transfer function position command and a standard move command profile generator position command to provide the follower axis position command. The latch is recalculated each time the follower mode is changed. A halt command can be used to selectively block or enable an independent move command signal, allowing the follower axis to remain in motion when the follower mode is turned off (not following the master axis), or allowing the follower mode to be turned on while the follower axis is in motion without a sudden change in position. Trigger calculation circuitry is used to precalculate timing for activating the follower mode when follower mode is changed from off to on while the follower axis is already in motion such that the axes are in phase after ramping time.
Abstract:
A method for a switching control mode of a servo control system which reduces a shock generated when switching from a torque control mode to a position/velocity control mode, the method comprising the steps of, in a torque control mode, rewriting a value in an integrator in a velocity loop for the position/velocity control mode to a value of a torque command of the torque control to thereby set a value of the integrator identical to that of the torque command, and obtaining, when switching from the torque control mode to the position/velocity control mode, a torque command value for a servo motor by using a value of the integrator of the velocity loop that is rewritten during the torque control mode, whereby continuous torque command values are given to the motor when a control mode is switched.
Abstract:
In an injection molding machine employing a servo motor as a source for driving the injection axle to drive the screw in the axial direction, a method is provided to smoothly shift the dwelling step to the metering/kneading step, in order to prevent the error register in the servo circuit from overflowing and to prevent the injection molding machine from coming into halt. When the dwelling step is finished, the error register is followed up (steps S6 to S8) such that the error quantity stored in the error register of the servo circuit that drives the servo motor for injection axle becomes zero. Then, a torque limit value to be applied to the servo motor is switched from a setpoint value for dwelling to a setpoint value for metering and kneading (step S11). The error register is then followed up again over a predetermined period of time from when the torque limit value is switched (step S13), and the step is shifted to the metering/kneading step (step S14).
Abstract:
An injection controller used for an injection molding machine which performs the injection and dwell control by means of a numerical control unit (30). Such a device is offered that the switching operation from the injection control to the dwell control is controlled according to the injection time and the resin pressure to improve reliability in the operation of the injection molding machine and to produce molded articles of good quality. Dwell control is started by dwell control means (30, 50, 60) when the resin pressure in the mold as detected by pressure detecting means (26) becomes greater than a preset pressure or when a predetermined period of time has passed from the start of the injection. When the pulse distribution is not completed up to the position of dwell completion when the dwell control is completed, an error register (51) of a servo circuit (50) is followed up by a follow-up means (30), so that the pulses are distributed forcibly.
Abstract:
A "mode switch" (45) is used for smoothly switching a servovalve controlled device such as an SMC press (10), in particular, from control under one parameter to control by another. The mode switch (45) provides a very smooth transfer of control from displacement control (47) between two relatively movable parts (20, 23) to force control (46) to provide for controlling the force exerted by actuators acting between the two parts (20, 23). The mode switch (45) electronically tracks the signals so that when the switching (64, 65) is made the signals are precisely equal to prevent abrupt changes in the control signals. This smooth transfer is achieved even under active control, that is when both control signals are changing in value.