In this study, the control of interaction torque between user and pneumatically driven wrist/forearm rehabilitation robot has been shown for forearm pronation and supination movements. In addition to the rotary encoder, a torque sensor, two pressure sensors, and two separate precise pneumatic proportional pressure regulating valves were utilized for each chamber of the semi-rotary pneumatic cylinder in the control setup. Although the control valves have their own inner control loops, an outer control loop has been designed and integrated into the valves by applying the PID control method to construct a cascade controlled system. With the addition of the PID method to the valves’ default inner controller, the control performance of the system was quite improved. Performance tests were carried out at two different interaction torque levels as high and low torque levels named as hard and soft interaction for both pronation and supination movements. At the end of performance studies, very promising results were obtained. The results were given in the form of real-time interaction torque and the percentage error deviating from the targeted interaction torque during motion. The study also demonstrates how successful pneumatic systems can be in force/torque feedback applications. The findings obtained from this study can be further utilized in pneumatic applications of haptic control.