Bird-Johnson
 SS-2-100 rotary
 actuator


 Hartmann
 HTF-5
 Relief valves Manifold hydraulic
 set at Block motor
 21000 kPa Assembly









 servo valve servo valve

 SFrom Pressure
 To Return From Pressure Manifold
 Manifold Manifold ToReturn
 Manifold

Figure 4.15. Circuit diagram of hydraulic Figure 4.16. Circuit diagram of hydraulic
 actuators for joints 0 and 1. motor actuator for joint 2.


series servo valve. The Sundstrand valve was mounted to the motor by a manifold block that

also provided for a case drain to the motor. Actuation of the rotating-lip picking mechanism

(Figure 4.17) was accomplished with a double-acting hydraulic cylinder (Allenair, 3500 kPa,

2.22 cm bore x 5.08 cm stroke) which was controlled by a 3-way solenoid valve energized by 120

volt AC current. Two solid-state relays were utilized to control the AC current. A pressure

reducing valve was used to reduce the hydraulic pressure to 3500 kPa for the actuating cylinder.


 Position Sensors

 The kinematics of the robot manipulator was developed with the understanding that

the position of each of the joints would be known. Control of the manipulator was based on the

ability to calculate the difference in the actual position from the desired position of each joint.

Rotary potentiometers were used to sense the actual position of each joint at any given time

(Figure 4.18).

 The position of each of the joints of the robot was sensed by 2k ohm potentiometers

directly connected to the actuators. For joints 0 and 1, Spectrol single turn potentiometers were