For a pneumatic actuator,precise positioning is difficult to obtain because of the compressibility of air and the static friction and Coulomb friction.This paper develops a nonlinear friction compensation scheme for p...For a pneumatic actuator,precise positioning is difficult to obtain because of the compressibility of air and the static friction and Coulomb friction.This paper develops a nonlinear friction compensation scheme for precise positioning of a pneumatic system.This Scheme is tested by simulation and experiment and is shown to be effective.展开更多
The distribution of incident angles of the discrete projection data may be uneven when the wave rays in random medium are nonlinear, moreover, the far field condition will be broken down when the inversion region is l...The distribution of incident angles of the discrete projection data may be uneven when the wave rays in random medium are nonlinear, moreover, the far field condition will be broken down when the inversion region is large. Thus the inversion result will be distorted unavoidably in many ray inversion methods. In order to eliminate these influences, a new t-x(time-spac) domain backprojection method compensating the density of the distribution of incident angles is developed. The paper provides the principle of the incident angle compensation and simulation result of a point defect in layered medium.展开更多
文摘For a pneumatic actuator,precise positioning is difficult to obtain because of the compressibility of air and the static friction and Coulomb friction.This paper develops a nonlinear friction compensation scheme for precise positioning of a pneumatic system.This Scheme is tested by simulation and experiment and is shown to be effective.
文摘The distribution of incident angles of the discrete projection data may be uneven when the wave rays in random medium are nonlinear, moreover, the far field condition will be broken down when the inversion region is large. Thus the inversion result will be distorted unavoidably in many ray inversion methods. In order to eliminate these influences, a new t-x(time-spac) domain backprojection method compensating the density of the distribution of incident angles is developed. The paper provides the principle of the incident angle compensation and simulation result of a point defect in layered medium.
