Control system for glassware forming machine
AssigneeEmhart Glass Machinery Investments Inc.
InventorsAlan Bradshaw, John Counsell, Philip A. Mann, Neil J. Plater
Life of this patent
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Abstract
A control system for controlling displacement of a member in a glassware forming machine. A pneumatic piston drives the member and is controlled by a computer which defines a motion profile. The difference, at any moment, between the demanded position and the actual position is determined and an error signal is defined based on the difference signal and the momentary velocity and acceleration.
Claims7
A control system for controlling the displacement of a member in a glassware forming machine which is to be displaced from a first to a second position comprising
- a pneumatic piston and cylinder device drivingly connected to the member and operable when air under pressure is supplied to said piston to displace the member from said first position to said second position,
- a proportional pneumatic valve including a solenoid displaceable to control the supply of air to said piston,
- a transducer for continuously issuing a signal representative of the position of the driven member as it is displaced from said first position to said second position,
- a valve controller for controlling the displacement of said solenoid, and
- a computer including
- means for defining a demand position for displacing said solenoid in accordance with a selected motion profile from said first position to said second position, and
- means for continuously determining the velocity of the member as it is displaced from said first position to said second position,
- means for continuously determining the acceleration of the member as it is displaced from said first position to said second position,
- means for continuously determining the difference between the actual position of the member and the demanded position, and
- means for generating an output signal for said valve controller
- defined by the following equation:
- OP=KP* (E* (ABS(ATAN(E*KN1))+KN2))-(Kd*V+Kdd*A)
- where
- OP is said output signal;
- KP is the proportional gain;
- E is the difference between the actual and demand positions;
- KN1 is the "sharpness" parameter;
- KN2 is the "base value" parameter;
- Kd is the first differential gain;
- V is the determined velocity;
- Kdd is the second differential gain;
- and
- A is the determined acceleration.
A control system for controlling the displacement of a member in a glassware forming machine which is to be displaced from a first to a second position comprising
- a pneumatic piston and cylinder device drivingly connected to the member and operable when air under pressure is supplied to said piston to displace the member from said first position to said second position,
- a proportional pneumatic valve including a solenoid displaceable to control the supply of air to said piston,
- a transducer for continuously issuing a signal representative of the position of the driven member as it is displaced from said first position to said second position,
- a valve controller for controlling the displacement of said solenoid, and
- a computer including
- means for defining a demand position for displacing said solenoid in accordance with a selected motion profile from said first position to second position,
- means for continuously determining the velocity of the member as it is displaced from said first position to said second position,
- means for continuously determining the acceleration of the member as it is displaced from said first position to said second position,
- means for continuously determining the difference between the actual position of the member and the instructed position, and
- means for generating an output signal for said valve controller defined by the following equation:
- OP=I-F+RKV.times.D
- where
- OP is the output signal for the valve controller;
- I=II+(1/ITR).times.RKI.times.E
- where
- E is the Error
- II is the integral of the error history
- RKI is the integral action gain
- F=RKP.times.P+RKd.times.V+RKdd.times.A
- where
- RKP is the proportional action gain
- RKd is the differential action gain
- RKdd is the second differential action gain
- V=velocity
- A=acceleration
- P is the actual position
- D is the demand position.
- RKV is the feed forward or kicker gain.
Dependencies are inferred from the claim text.