Picking
 Mechanism-
 Picking r Pivot for Joint 0 Actuator
 Mechanism -




 I I i I
 A B


 ---- Robot Support



 Actual Position Computer
 A (cm) B (cm) A/D Value Position
 131.5 0 2321 fully extended (to stop)
 129.0 2.5 2350 low
 124.5 7.0 2400 min
 54.5 77.0 3200 home
 10.5 121.0 3700 max
 2.0 129.5 3800 high
 0 131.5 3821 fully retracted (to stop)


Figure 4.21. Relationship between position of joint 2 and the A/D value of the position of
 joint 2.


significantly reduce the ability to control the position of the orange-picking manipulator. A

summary of the conversion factors for converting A/D values to actual positions of the joints is

presented in Table 4.2.


 Velocity Sensors

 Effective control of the robot required a direct reading of the velocity of each joint. The

velocity of the joints was monitored by the use of DC tachometers (Figure 4.22) mounted to the

actuator or linkage of each of the joints. The voltage output from each of the tachometers was

quantified by 12-bit A/D converters with an input range of 5 volts. This range gave a digital

resolution of 409.6 bits per input volt from each of the tachometers.