In this paper, a novel strategy is designed for trajectory control of a multi-section continuum robot in three-dimensional space to achieve accurate orientation, curvature, and section length tracking. The formulation connects the continuum manipulator dynamic behavior to a virtual discrete-jointed robot whose degrees of freedom are directly mapped to those of a continuum robot section. Based on this connection, a computed torque control architecture is developed for the virtual robot, for which inverse kinematics and dynamic equations are constructed and exploited, with appropriate transformations developed for implementation on the continuum robot. The control algorithm is implemented on a six degree-of-freedom two-section OctArm continuum manipulator. Experimental results show that the proposed method managed simultaneous extension/contraction, bending, and torsion actions on multi-section continuum robots with decent tracking performance (steady state arc length and curvature tracking error of merely 3.3mm and 0.13m-1, respectively). These results demonstrate that the proposed method can be applied to multi-section continuum manipulators and perform complex maneuvers within a nonlinear setting.

Continuum robots have long held a great potential for applications in inspection of remote, hard-to-reach environments. In future environments such as the Deep Space Gateway, remote deployment of robotic solutions will require a high level of autonomy due to communication delays and unavailability of human crews. In this work, we explore the application of policy optimization methods through Actor-Critic gradient descent in order to optimize a continuum manipulator's search method for an unknown object. We show that we can deploy a continuum robot without prior knowledge of a goal object location and converge to a policy that finds the goal and can be reused in future deployments. We also show that the method can be quickly extended for multiple Degrees-of-Freedom and that we can restrict the policy with virtual and physical obstacles. These two scenarios are highlighted using a simulation environment with 15 and 135 unique states, respectively.

Developments of robot arms are countless, but there has been little focus on robot surfaces for the reshaping of a habitable space—especially compliant surfaces. In this paper we introduce a novel, tendon-driven, robot surface comprised of aggregated, overlapping panels organized in a herringbone pattern. The individual 3D-printed panels and their behavior as an aggregation are inspired by the form and behavior of a pinecone. This paper presents our concept, design, and realization of this robot, and compares our prototype to simulations of four physical configurations that are formally distinct and suggestive of how the surface might be applied to habitable, physical space in response to human needs and wants. For the four configurations studied, we found a validating match between prototype and simulations. The paper concludes with a consideration of potential applications for robot surfaces like this one.

We discuss motion planning in the configuration spaces of robots containing continuum elements. The configuration space structure of extensible continuum sections is first analyzed, with practical constraints unique to continuum elements identified. The results are applied to generate the configuration space of a hybrid continuum lamp/mobile base robot. A conventional motion planning RRT/A* approach is subsequently applied for the robot in an aging in place application scenario.

In this paper, we describe a novel nonlinear control strategy for the closed-loop control of extensible continuum robots. Previous attempts at controlling continuum robots have proved difficult due to the complexity of their system dynamics. Taking advantage of a previously developed dynamic model for a three-section, planar, continuum manipulator, we develop an adaptation-based control law. We present simulation results of a set-point tracking between a rigid-link control device and an extensible continuum manipulator. Experimental results of the controller implemented on a six degree-of-freedom continuum robot are also presented.

In this paper, we show how structures and strategies employed by thin-stemmed plants can be adapted to improve robot access to unstructured and congested environments. Specifically, we show how the use of vine-inspired movement strategies can enhance long thin continuum robot exploration and inspection operations. We introduce a new theoretical plant growth-inspired approach for modeling and motion generation of continuum robot backbones. The approach is demonstrated in numerous experiments including inspection within a high fidelity, full-scale mock-up of the International Space Station at NASA Johnson Space Center, using novel robot tendril hardware.

Continuum (continuous backbone) robots are suitable for operation in unstructured environments thanks to their inherent compliance. They can adjust their shape to navigate through complex environments and grasp a wide variety of payloads with their compliant backbones. However, controller design for continuum robots is challenging due to their complex dynamics. In this paper, we introduce a new and novel strategy for trajectory control of continuum robot sections. The approach is based on a virtual discrete-jointed robot whose degrees of freedom are directly mapped to those of a continuum robot section. A conventional control strategy is developed for the virtual robot, for which inverse kinematics and dynamic equations are formulated and exploited, with appropriate transformations developed for implementation on the continuum robot. Simulations of the virtual robot computed torque control were executed and results indicate that the control method has good trajectory tracking performance. The control algorithm was implemented on a three degree of freedom section of the OctArm continuum manipulator, with decent tracking performance (steady state tracking error of merely 3mm during extension).

We present a novel approach to teleoperation of continuum robots. In contrast to previous approaches restricted to three Degree-of-Freedom (DoF) joysticks, a six degree-of-freedom rigid-link manipulator is used as the input device. Mappings from the rigid-link arm to the continuum robot are synthesized and analyzed, focusing on their potential for creating a more intuitive operational interface. The approach was implemented using a six degree-of-freedom rigid-link manipulator as input device for teleoperation of a three section, nine degree-of-freedom continuum robot. Tests were conducted across a range of planar and spatial tasks, using fifteen participant operators. The results demonstrate the feasibility of the approach, and suggest that it can be effective independent of the prior robotics, gaming, or teleoperative experience of the operator.