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 Property Value Name Proportional Control for Position Description If a car is programmed to travel 12?, how do we know is actually traveled that distance? Often, the cars momentum will carry it past the desired location even though the motors have stopped running. The solution to this problem is a proportional control loop. By continually monitoring the distance from the desired location, the motor speed can be slowed as the car approaches. The governing formula is defined as P*(desired-current) where P is an arbitrary constant. In this program, a desired location is set at 50 degrees of the rotation sensor. This value is continually subtracted by the current rotation traveled. The difference is multiplied by two and this becomes the value of the "power" variable. The Compare Block determines the direction Motor C will travel: forward if "power" is positive, backward if "power" is negative. Thus, when the car first starts off, its current position is zero and its desired position is 50. Therefore, the power setting used is 100, which is full power forward. If the car overshoots its mark, the power setting will become negative and the car will travel in reverse. The goal of proportional control is to find a constant that will get the system to equilibrium in the shortest time with the least amount overshoot and the most accuracy. Filename 21 - Proportional Control for Position.rbt Filesize 662.08 kB Filetype rbt (Mime Type: application/octet-stream) Creator mu579 Created On: 05/31/2006 13:04 Viewers Everybody Maintained by Editor Hits 7843 Hits Last updated on 07/02/2007 13:02 Homepage CRC Checksum MD5 Checksum