MOTION CONTROL ISAT 303 Typically involves accurate control of distance, speed (angular velocity or both.

Manufacturing Applications w Welding robots - automobile body fabrication w assembly robots e.g. microelectronics w robots for painting w machining operations w injection molding w application of glue to assembly parts w microscope positioning for precision measurements.

Actuation, Sensing & Analysis w Actuation follows sensing and analysis in automated control Sensor Analysis device Actuator Linkage Device Motor drives Annunciation On/off switches PLC, PC

Motor Indexer PC Encoder

Optical Encoders w Optical Encoder – “ is a digital device used to measure position and/or speed, consisting of a slotted disk separating a light source from a photocell. As disk rotates, photocell senses light through slots as a series of pulses. Number and frequency of pulses are proportional (respectively) to position and speed of shaft connected to the disk” w They are used for both linear and rotational measurements.

Encoder Application w Closed loop positioning is used in critical applications to ensure accuracy. During a move, the indexer compares the number of encoder steps (inputs) against the motor steps (outputs) and makes any necessary adjustments. w An encoder can also be used to detect if a stall has occurred during a move.

Encoder Application: w Stall detection applications include: Positioning glass vials in blood analysis Chemical mixing X-ray head/tube positioning Laser or water jet cutting Polishing mirrors for telescopes Drawing fiber optics w Position Maintenance Application: Robotics and material removal

Encoder Accuracy w Resolution (or resolution error) – is the inability of measurement system to follow changes in measurand exactly. It is treated as a precision error. Resolution = counts/deg. change X 360 deg/1 revolution = counts (steps) per revolution w Higher counts per revolution translates to higher precision