Abstract of Dissertation Presented to the Graduate School
 of the University of Florida in Partial Fulfillment of the
 Requirements for the Degree of Doctor of Philosophy

 MOTION CONTROL OF A CITRUS-PICKING ROBOT

 By

 Thomas Alan Pool

 May, 1989



Chairman: Dr. Roy C. Harrell
Major Department: Agricultural Engineering

 This work focused on the design and implementation of motion control strategies for a

citrus-picking robot. These control strategies were used by an intelligence base for the robot

which required precise control of the individual joints based on information from velocity,

position, and vision sensors. The type of controller that was used at any instant was determined

by this intelligence base, which called the applicable controller and supplied it with

setpoints.

 Initially, the design of the hydraulically actuated, three degree-of-freedom,

spherical coordinate arm was presented. The picking mechanism housed the vision and

ultrasonic sensors, which provided real-time end of the arm fruit position sensing and a rotating

lip for removing the fruit from the tree. From the known dimensions of the robot, a kinematic

model was derived. This model provided a basis upon which the position of the joints could be

related to the information detected by vision sensor. Dynamic models of the robot joints were

experimentally determined for use in designing and tuning the joint controllers. Lag-lead

compensators were chosen for their ability to improve a system's steady state performance

while improving the response rate by increasing the system bandwidth. These controllers were

discretized and programmed into the software environment of the robot.

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