MPR027 - GROUP 3 - BIKE PUMP PROJECT

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MOTOMAN XRC - MODEL UP6

The Motoman robot used in our cell is a new robot purchased in 1999, allong with the Pinacho CNC lathe and the PLC system.  Programing the motoman was a difficult task at times, because of this reason.  No one had any extensive knowledge of this machine.      The basic programing of points is pretty strait forward.  There are two ways to do it.  The first and most commonly used by us was the assiged point system.  The XRC computer system attached to the Motoman has the ability to store 127 points.  These points were divided equally among the three groups, which left us with 42 points at our

dissposal.  By bringing the robot to the disired position of movement, and assigning these points, the robot would go in and around our fixtures.  One advantage to assigning points in this way was that the same point could be used more than once, in the same program or a totally different program.  It also made it easy to adjust points without acctually editing the program itself.  Once the point is changed,  it changes for every program it is used in.  The only disadvantage to this, is that the robot will move to each point whichever way it wants.  This causes a problem if one of its axis are at mid rotation.  It's difficult to predict which way it will move to the next point.  One way to solve this is to change the motion type to the next point, joint motion, lateral motion, or circular motion.  Though this doesn't always solve the problem, many times it makes it worse.  Adding extra points between each destination seems to be the most effective way.  Using assiged points may not be so relyable, which is why the other way of programing points may be used.  Within the program, points may be added by simply going to the point and inserting it as a motion command.  When assigned in this manner, the robot will go to the exact point of rotation for each axis, eliminating any chance of alarm signals due to overrotation or missed point accuraccy due to miss rotation.      After the points are set, all that is left is to insert signals and commands whithin the program.  Timer commands, wait for input commands, and output signals for communicating with the PLC just to name a few. For example, when the Motoman gets to the lathe and the raw material is in the right position, a signal must be sent out telling the PLC its reached its destination.  The PLC sends a signal to the lathe to close it's jaws, a signal goes back to the PLC, then another to the Motoman which is waiting for a signal to open its claw and exit the lathe.

The Motoman has two different attachments it uses in this assebly process.  The Gripper (left), which is desiged to pick up large round material, such as the raw material and the cylinder, with its V-shaped area.  As well as flat sidded material with the tip of the gripper.  As you can see, the tip of the gripper has quite a sharp angle.  This is for getting into The Golden Sisters (raw material and cylinder magazine).  Because the magazine was built before the gipper, we ran into a little problem getting to the material in this magazine while still having a flat gripper edge avaiable for other materials. A simple solution followed, the gripper would

have to enter from the top side, moving the extra material out of the way before grippin the desired piece. See Video. Another tool, The Screwer, also played an important roll in the assembling the pump. The screwer is nessasary for retreaving the screw from the "Snail" and inserting the screw into the tapped whole made made by "Rocco".  The most difficult part off using this tool was aligning the screw with the drilled hole.  Because of robot position error in both robots, and error in the positioning of the screw bit in the screwer itself, getting the two to line up consistantly was a project in itself.        See Video.