A Hybrid Dual Jacobian Approach for Autonomous Control of Concentric Tube Robots in Unknown Constrained Environments

Inverse kinematics (IK) of concentric tube continuum robots (CTRs) is associated with two main problems. First, the robot model (e.g., the relationship between the configuration space parameters and the robot end-effector) is not linear. Second, multiple solutions for the IK are available. This paper presents a general approach to solve the IK of CTRs in the presence of constrained environments. It is assumed that the distal tube of the CTR is inserted into a cavity while its proximal end is placed inside a tube resembling the vessel enabling the entry to the organ cavity. The robot-tissue interaction at the beginning of the organ-cavity imposed displacement and force constraints to the IK problem to secure a safe interaction between the robot and tissue. The IK in CTRs has been carried out by treating the problem as an optimization problem. To find the optimized IK of the CTR, the cost function is defined to be the minimization of input force into the body cavity and the occupied area by the robot shaft body. The optimization results show that CTRs can keep the safe force range in interaction with tissue for the specified trajectories of the distal tube. Various simulation scenarios are conducted to validate the approach. Using the IK obtained from the presented approach, the tracking accuracy is achieved as 0.01 mm which is acceptable for the application.

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Design of Concentric Tube Robots Using Tube Patterning for Follow-The-Leader Deployment

Journal of Mechanisms and Robotics ◽

10.1115/1.4047983 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Cédric Girerd ◽

Thomas Schlinquer ◽

Nicolas Andreff ◽

Pierre Renaud ◽

Kanty Rabenorosoa

Keyword(s):

Design Process ◽

Constant Curvature ◽

Stability Criterion ◽

Medical Applications ◽

Application Field ◽

Concentric Tube Robots ◽

Constrained Environments ◽

The Stability

Abstract Concentric tube robots (CTRs) have a great potential for use in medical applications. Coupled with a follow-the-leader (FTL) deployment, they allow navigation in constrained environments. However, they are subject to instabilities if one makes use of high curvatures for the tubes, long overlapping lengths of their curved sections, or long transmission lengths. One approach to improve their stability is to pattern the tubes of which they are composed by local removals of material along their lengths. Applying patterns on tubes was proved to be of interest for given deployed lengths of a CTR. In this article, we present a method to enlarge the application field of CTRs that deploy in a follow-the-leader manner, by integrating tube patterning in the design process, with a stability criterion. Our method allows the designer to determine a custom pattern geometry to theoretically ensure the stability of CTRs made of any number of constant curvature tubes, for a complete FTL deployment sequence, and while respecting a desired shape during deployment.

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Impacts of Output Fluctuations from Photovoltaic Power Generation Systems on the Autonomous Control of Step Voltage Regulators Operatable under Reverse Power Flow Conditions

IEEJ Transactions on Power and Energy ◽

10.1541/ieejpes.137.154 ◽

2017 ◽

Vol 137 (2) ◽

pp. 154-155 ◽

Cited By ~ 4

Author(s):

Tomohiro Nagashima ◽

Taku Noda ◽

Michiharu Ichikawa ◽

Toshiyuki Seto ◽

Toshiyuki Musashi ◽

...

Keyword(s):

Power Generation ◽

Power Flow ◽

Autonomous Control ◽

Voltage Regulators ◽

Flow Conditions ◽

Step Voltage ◽

Photovoltaic Power ◽

Output Fluctuations ◽

Power Generation Systems

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Development of an unmanned tractor chassis for precision farming

10.36652/0042-4633-2020-5-47-53 ◽

2020 ◽

pp. 47-53

Author(s):

YU.V. Galyishev ◽

R.Yu. Dobretsov ◽

G.P. Porshnev ◽

E.G. Saharova ◽

D.V. Uvakina ◽

...

Keyword(s):

Precision Farming ◽

Autonomous Control ◽

Kinematic Scheme ◽

Local Complex ◽

Friction Clutch

The development of the chassis of an unmanned tractor for a local complex of precision fanning is considered. The design is based on the kinematic scheme of the shaft gearbox, which implements a large number of modes and the principle of two-line transmission. A feature of this scheme is the presence of parallel load shafts. Keywords: wheeled tractor, autonomous control, two-line transmission, slipping, disc friction clutch. [email protected]

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