The pneumatic rotary position system, in which an electro-pneumatic proportional flow valve controled a rotary cylinder, was studied, and its mathematical model was built. The model indicated that the controlled pneumatic system had disadvantages such as inherent non-linearity and variations of system parameters with working points. In order to improve the dynamic performance of the system, feed forward compensation self-tuning pole-placement strategy was adopted to place the poles of the system in a desired position in real time, and a recursive least square method with fixed forgetting factors was also used in the parameter estimation. Experimental results show that the steady state error of the pneumatic rotary position system is within 3% and the identified system parameters can be converged in 5 s. Under different loads, the controlled system has an excellent tracking performance and robustness of anti-disturbance.
Force feedback dataglove is an important interface of human-machine interaction between manipulator and virtual assembly system,which is in charge of the bidirectional transmission of movement and force information between computer and operator. The exoskeleton force feedback dataglove is designed taking the pneumatic artificial muscle as actuator,meanwhile,its structure and work principle are introduced,and the force control problem is analyzed and researched by experiment. The mathematic model of grasping rigid object for finger is established. Considering the friction of tendon-sheath system and finger deformation,the closed-loop force control for a single joint,a single finger and multi-fingers are studied respectively by the feedforward proportional-integral(PI) control method with variable arguments. On the premise of the force smoothness,the control error of the force exerted on the finger joint is in the range of ±0.25 N,which meets the requirement of force feedback. By experimental analysis,the reason of force fluctuation is that the finger joint has a small amplitude quiver,and the consistent change tendency of the force between proximal interphalangeal(PIP) joint and distal interphalangeal(DIP) joint results from their angle coupling relationship.
