In this paper, we investigate the limit cycle of a biped walker driven by pairs of pneumatic artificial muscles. We show, experimentally, that the period of the limit cycle changes when different control parameters are applied and estimate the relationship between the period and the parameters through trials. A step-by-step feedback controller is proposed to stabilize walking based on the estim...

This paper presents a nonlinear optimal control scheme for a mechatronic system that consists of a guided carriage and an antagonistic pair of pneumatic muscles as actuators. Modelling leads to a system of nonlinear differential equations including polynomial approximations of the volume characteristic as well as the force characteristic of the pneumatic muscles. The proposed control has a casc...

A fractional-order control strategy for pneumatic position servosystem is presented in this paper. The idea of the fractional calculus application to control theorywas introduced inmanyworks, and its advantages were proved. However, the realization of fractional-order controllers for pneumatic position servosystems has not been investigated. Based on the relationship between the pressure in cyl...

A new parallel-type gripper mechanism is proposed in this work. This device has a parallelogramic platform that can be flexibly folded. Therefore, this mechanism not only can be used to grasp an object having irregular shape or large volume, but also can be utilized as a micro-positioning device after grasping objects. Forward position analysis and platform kinematics are investigated to deal w...

There are three forces acting on the valve plate: the force of the escaping air Fv, the force of the steel spring Fs and the pneumatic damping force due to the pressure of the air in the dashpot Fd. Each of these forces varies with distance x. These interact with the valve mass and the pipeline dynamics to produce instability. Perturbations in the pressure travel along the pipe at the sonic vel...