the joints. In the controlled environment of a laboratory, this vision-servoing method was

proven to have potential for control of a grove model robot.

 Tests in the grove, however, indicated that the black-and-white camera could classify

light reflections from the soil as fruit. Therefore, the use of color vision was investigated

(Slaughter et al., 1986; Slaughter, 1987; Slaughter and Harrell, 1987). In his work, a scheme

was developed which segmented the image into fruit and background regions based on the color

of each pixel. From this image, the centroid of each fruit's image could be determined for use in

adjusting the joints of the robot to point towards the fruit. Since the image was processed in

real-time, the robot could be controlled to track the dynamic motion of the targeted fruit.

 In a joint project between researchers at the University of Florida and AID of Italy, two

robots were designed and constructed as prototypes for future work aimed at a commercially

produced tree-fruit-picking robot (Harrell and Levi, 1988). The AID robot relied on electrical

servo controllers to position the joints to point the arm towards the fruit. A global vision system

was used to determine the location of the fruit throughout the picking sequence. The Florida

robot further developed the previous concepts while implementing the vision system of

Slaughter. A hydraulically actuated robot was designed and constructed with a spherical

coordinate architecture (RRP).

 For this prototype, a controller was not available. Even if a controller were available,

the exclusive use of point-to-point joint positioning would not have provided the desired

flexibility. The robot motion was to be formulated based on velocity and vision requirements as

well. An intelligence base for the robot was designed and programmed (Adsit, 1989). This

intelligence base added a requirement for fast and accurate control of the joints of the robot

based on velocity, position, and vision setpoints. The design and implementation of these

controllers is the scope of this work.