Research On Control Of Cable-driven Continuum Redundancy Robot

Continuum robot is a new kind of robot inspired from bionics,which is looking forward to work with space exploration,nuclear power manipulating,emergency rescure,and so on.The continuuum robot has been a hotspot in the area of robotic research.The mobile ability is supported by binonic spine and bionic skin for the continuum with rigid structure.The external force is transmitted to the bionic body by the skin,while the bionic spine provides the driving force.In this paper,we developed a new bionic spine for the continuum robot,which brought in the hyperredundant feature and elastic.The excellent ability of locomation for the robot is reflected by dynamic optimization and designing control rules.The bionic mechanism is cable-driven and hyper-redundant mechanism,which is formed with 6 tendem cardan joints and 6 parallel spring sets.Every rigid body is drived by 3 tethers,while the whole mechanism is drived by 18 tethers which is equispaced at a peryphery and parallel to the axis of the bionic spine.In the dynamic model,the springs and tethers can be simplied as force and all the constraints are regarded as ideal constraints.The force on the tethers and springs can be transformed into single force and torque acting at the body-fixing cordinate system by Newon-Euler methord.The jacobin matrix between drving-force and equvalent joint-torque can be calculated by this simplified method.The dynamic equations can be established by Lagrangian method,then the inertia metrix,Coriolis force,equivalent gravity can be calculated.The dynamic properities can certify the rationality of mechanical design.The force of tethers can be calculated by the inverse dynamic model.The multiplicity of velocity from cartesian space to joint space and the foce from joint space to driven space is determined by the hyper-redundant and overdrive properities of the bionic spine.The optimizable potential is exist at the kinamic a nd dynamic field.The optimization objects are angle of joints and force of tethers.The vectors in null space of velocity jacobin matrix and force jacobin matrix are determined by the gradient method and null space method.The multi-objective optimization for kinamics and dynamics is realized by slecting the property null space vectors.The control system is used for keeping kinetic stability of the bioninc mechanism.This paper presents a optimizing control rate for the continuuum redudancy robot by using calculating-torque control and the multipurpose optimal method.The control rate has strong stability and signal tracing capability.This paper verfied the bioninc locomotive capability of the mechanism by runing the dynamic-optimization program and co-simulation technology.The result of the simulation experiment has proved that the mechanism can realize 2D and 3D locomotion flexibly and has Strong ability of dynamic optimization.All the theory and experiment shows that the new mechanism is suitable for the cotinuum robot.