Forward displacement analysis of a redundant parallel manipulator by approximation algorithms

This paper presents the forward displacement analysis of an 8-PSS(prismatic-spherical-spherical)redundant parallel manipulator whose moving platform is linked to the base platform by eight kinemtic chains consisting of a PSS joint and a strut with fixed length.A general approximation algorithm is used to solve the problem.To avoid the extraction of root in the approximation process,the forward displacement analysis of the 8-PSS redundant parallel manipulator is transformed into another equivalent problem on the assumption that the strut is extensible while the slider is fixed.The problem is solved by a modified approximation algorithm which predicates that the manipulator will move along a pose vector to reduce the difference between the desired configuration and an instantaneous one,and the best movement should be with minimum norm and least quadratic sum.The characteristic of this modified algorithm is that its convergence domain is larger than that of the general approximation algorithm.Simulation results show that the modelified algorithm is general and can be used for the forward displacement analysis of the redundant parallel manipulator actuated by a revolute joint.

耳穴压豆治疗热结肠燥型便秘随机平行对照研究

[目的]观察耳穴压豆治疗热结肠燥型便秘疗效。[方法]使用随机平行对照方法,将100例住院患者按病志号抽签方法简单随机分两组。对照组50例乳果糖口服液,10m L/次,3次/d。治疗组50例选大肠、直肠、便秘点、三焦及肺穴中的3-4个穴位行耳穴压豆,用耳穴探棒寻找压痛点,压痛最明显的为耳穴治疗点;取王不留行籽按压在穴位,胶布固定,拇指、食指对捏按压王不留行籽,以有疼痛或胀痛感,能耐受为度;保留7d,指导患者每天按压3-5次,1-2min/次。连续治疗1周为1疗程。观测临床症状、大便性状、不良反应。治疗1疗程,判定疗效。[结果]治疗组痊愈13例,有效28例,无效9例,总有效率82.00%;对照组痊愈3例,有效26例,无效21例总有效率58.00%;治疗组疗效优于对照组（P〈0.05）。[结论]耳穴埋籽治疗热结肠燥型便秘,疗效满意,无严重不良反应,值得推广。