Hyper-redundant manipulator has a slim geometric shape and super high degrees of freedom (DOF), which promises high motion efficiency and flexible obstacle avoidance ability in a confined space. Nevertheless, it also challenges the more complicated motion control strategy. In this article, the concepts of “link eigenvectors” and “manipulator's eigenpoints,” which apply to a widely used geometric kinematics method, are proposed. Hence, the kinematic and dynamic models can be constructed intuitively. And since the indirect joint space and local frames are replaced by the link eigenvectors and unified global frame, the kinematic and dynamic problems, especially the link's position, velocity, and acceleration, can be solved more directly. Further, based on the new models, mechanical analysis and Newton–Euler dynamic equations are effectively simplified, so as to realize the fast and precise dynamic resolution. Experiment results show that the kinematic and dynamic theoretical models are correct. And the driving forces of motors are successfully optimized, while the kinematic precision is improved simultaneously.

While a great number of degree of freedom (DOF) of hyper-redundant manipulators brings superior dexterity, it also challenges the more complicated kinematics algorithms. The kinematics method can not only affect its flexibility and obstacle avoidance ability, but also determine whether it runs efficiently and reliably. Hence, in this article, an effective kinematics method has been proposed based on the morphologic space constraints. It decomposes the resolution of inverse kinematics into two steps: 1) setting the target morphologic space and 2) tracking the morphologic space. In addition, because the proposed kinematics method would calculate the link end positions first but not the joint parameters, this article discards the joint space and obtains the configuration space more directly, by which the method would be more intuitive and efficient. Afterward, a serpentine scanning motion mode, which is efficient, reliable, and of high performance in obstacle avoidance, was studied. Simulation and experiment results show that the kinematics method and serpentine scanning motion mode can meet the requirements of real-time control and obstacle avoidance.

Snake-like robots, which have high degrees of freedom and flexibility, can effectively perform an obstacle avoidance motion in a narrow and unstructured space to complete assignments efficiently. However, accurate closed-loop control is difficult to achieve. On the one hand, this is because adding too many sensors to the robot will significantly increase its mass, size, and cost. On the other hand, the more complex structure of the hyper-redundant robot also challenges the more elaborate closed-loop control strategy. For these reasons, a cable-driven snake-like robot, which is compact and low cost, with force transducers and angle sensors, is designed in this article. The simpler and more direct kinematic model is studied, which applies to a widely used kinematics algorithm. Based on the kinematic model, the inverse dynamics are resolved. Finally, this article analyzes the sources of the motion errors and achieves dual-loop control through force-feedback and pose-feedback. The experiment results show that the robot’s structure and dual-loop control strategy function with high accuracy and reliability, meeting the requirements of engineering applications and high-precision control.