PPV girdle drop
 fruit retract fruit
 ppp approach ret
 fruit
 d ViViV i

 150 I Joint Position


 100 -


 o 50
 O0 Position Setpoint I

 0-

 50I
 Joint Velocity


 50 -



 -50
 Velocity Setpoint A
 II
 -100- I I

 0 30 60 90 120 150 180
 Time (1/60 sec)

Figure 9.24. Control modes and position and velocity of joint 2 during a typical pick cycle.


of the tree while joints 0 and 1 were held stationary under position control (PPV). When the

slider reached its home location (150 ticks), the control of all joints were switched to position

control, all joints were instructed to go to their home locations, and the fruit was released from

the picking mechanism. Thus, a pick cycle was completed and the intelligence base was ready

to check for another fruit.

 During this pick cycle, joints 0 and 1 acted under the control of the vision and position

controllers while joint 2 acted under velocity control and position control. The motion

controllers provided adequate control over the joints of the robot for removing a fruit from the

tree. As the end-effector was extended towards the fruit, changes in the velocity setpoint for