Dynamics And Control Of Cable-driven Silicone Soft Manipulator

With the development of technology, robots are utilized in increasingly wider applied fields, which are not confined to traditional industry or scientific research, but part of our daily lives.However, limited by the rigid structure and material, traditional rigid robotic can’t meet the requirements for the specified application or intended use when applied to unstructured environment. Under such circumstances, a kind of novel robot—soft robot appears as an important complement to traditional rigid robot. Compared with traditional rigid robot, soft robot’s advantages are the softness and flexibility due to the soft materials and soft structures,which make it possible for the soft robot to work in the unstructured environment freely.Despite the overwhelming superiority of soft robot,the softness complicates the movement rule of the soft robot,which makes it rather difficult to build the accurate model and design control algorithm, hence limit the applications of soft robot in our daily lives. In order to deal with the problems of soft robot mentioned above, this work focus on not only the kinematics and dynamics of cable-driven soft manipulator, but also the controller and shape detecting algorithm development. The main contents and innovations of this thesis are summarized as follows:Firstly, the kinetic characteristics of cable-driven soft manipulator in narrow and disorder environment are analysed.And the forward kinematics and differential kinematics of cable-driven soft manipulator based on piecewise constant curvature assumption are proposed. In addition, an adaptive control algorithm for the eye-in-hand system of soft manipulator is developed. The adaptive controller enable the convergence of soft manipulator’s motion in narrow environment by estimating the unknown parameters of the differential kinematics online. The contrast experiments are designed to validate the adaptive control algorithm and analyse the impact of related parameters.Then, the forward kinematics are improved based on piecewise constant curvature assumption and a new forward kinematics of soft manipulator is developed by combining the geometrical accurate Cosserat rod theory. In addition, a new three dimensional dynamics of cable-driven soft manipulator based on new kinematics and Kelvin model of viscous-elastic material is proposed, by utilizing the Kane’s method. The dynamics contains four kinds of forces and moments: the inertia forces and moments of each segment of soft manipulator based on lumped parameter assumption; the elastic forces and moments based on Cosserart rod theory and Kelvin model; driven forces and moments based on cable-driven principle. The contrast experiments between numerical simulations and business software(Recur Dyn) are designed to validate the dynmics.Finally, a distributed sensor network based on FBGs and relevant algorithm are proposed to deal with the shape detecting problem of soft manipulator in closed environment. The sensor network can measure the curvatures and torsions of soft manipulator simultaneously. Based on fair curve theory, a shape detecting algorithm, which can translate the curvature and torsion measured by sensor network into the soft manipulator’s shape, is proposed. Eventually, high accuracy for three dimensional shape the shape detecting method introduced in this paper can achieve is validated by three dimensional simulations.