Asimple industrial robot has four axes of motion, controlled by four separate motors. we will refer to the motions as turn" (right or left), "lif" (raise or lower), "extend" (in or out), and grip" (contract or release). when the robot is programmed to perform a task, a sequence of these motions will take place. for example, to pick up an object, the arm would turn to align with the object, extend to reach it, grip it, and lift. we are interested in predicting how the actions will occur, in order to accelerate the controlling software. if, for example, a turn is most likely to be fol- lowed by an extension, the code that controls the extension can be readied in advance. from a sam ple of robot programs, representing a set of typical tasks, the following count data was derived: 90 20 20 30 15 80 40 50 30 15 40 15

Ashielded metal arc-welding operation is accomplished in a work cell by a fitter and a welder. the fitter takes 5.5 min to load components into the welding fixture at the beginning of the work cycle, and 1.5 min to unload the completed weldment at the end of the cycle. the total ength of the weld seams 1200 mm, and the travel speed used by the welder averages 300 mm/min. every 600 mm of seam length, the welding stick must be changed, which takes 0.8 min. while the fitter is working, the welder is idle (resting): and while the welder is working the fitter is idle. (a) determine the average arc-on time as a fraction of the work cycle time. (b) how much improvement in arc-on time would result if the welder used flux-cored arc welding (manually operated), given that the spool of weld wire must be changed every 10 weldments, and it takes the welder 5.0 min to accomplish the change? (c) what are the production rates for these two cases (weldments completed per hour)? attach your work and solutions.