Continuum robots are promising systems for minimally invasive surgical procedures, enabling safe and dexterous access to deep regions in the human body. Their design and fabrication can be adapted to a wide range of application‐specific requirements. Unfortunately, the current lack of standardized methods for producing these designs impedes the development and adoption of new continuum robots (CRs). Herein, a parametric design methodology is introduced for producing a wide variety of CRsbased on application‐specific requirements. This approach is based on interlocking ball joint subunits that enable the generation of modular systems. The methodology is demonstrated by designing a magnetically actuated continuum robot for cardiac ablations. The design is generated using an open‐source parametric computer‐aided design toolbox, and prototypes are experimentally validated in vitro and ex vivo, demonstrating the ability of the toolbox to produce functional systems with minimal effort and input from the user.

Teleoperated robotic surgery is a rapidly growing field that promises to overcome geographical barriers and share expertise over long distances for a variety of minimally invasive procedures. A particularly promising technology for teleoperation is robotic magnetic navigation. In contrast to conventional surgical robots, a robotic magnetic navigation system generates external magnetic fields to safely and dexterously steer soft magnetic devices within the human body, enabling a versatile, economical, and accessible telesurgery platform for a variety of procedures. This perspective highlights the recent research efforts in robotic magnetic platforms for telesurgery and their translation to clinical settings in the context of endoscopic procedures. This discussion is supported by a case study performed at the Multi‐Scale Medical Robotics Center in Hong Kong, where an in vivo gastroscopy in a porcine model is performed in tandem with two operators, alternating between a clinician controlling the procedure from the operating room in Hong Kong and a remote expert controlling the procedure from an operator console in Zurich. The achievements and challenges of this study highlight the capabilities and future potential of robotic magnetic navigation for telesurgery.

Soft micromachines made out of stimuli-responsive hydrogels have the potential to emulate the navigation strategy of leukocytes to implement autonomous targeted drug delivery. Leukocytes navigate in their natural environment with a variety of strategies in response to chemical gradients. They can detect gradients and redirect their movement towards the gradient source, or adjust their speed while moving up-gradient through cell body morphing known as cell polarization. In this work, we use thermo-responsive hydrogels to engineer self-folding micromachiness that can sense near infrared (NIR) light gradients and react in a morphing manner to adjust their speed. We load drug molecules into the unfolded micromachines and encapsulate the drug by folding the micromachines at body temperature. A location of interest is targeted with an NIR light, and a rotating magnetic field is applied to navigate the microrobots to explore the region. Results from in vitro experiments demonstrate that the robots speed up while moving up-gradient, automatically stop at the location of interest, and start to release the encapsulated drug molecules by unfolding their shape. The autonomous navigation is achieved without any external imaging feedback by coordinating the sensory input and shape morphing output of the microrobots through the single degree of freedom (DOF) shape control.

Recent advances in magnetic nanocomposites have enabled untethered micromachines with controllable shape transformations and programmable magnetic anisotropy, paving the way for a variety of biomedical applications using soft microrobots. Magnetic anisotropy is programmed by assembling the embedded magnetic nanoparticles (MNPs) in polymeric materials to overcome the shape anisotropy of a given structure. However, this approach is questionably effective in reconfigurable structures, as shape changes naturally result in rearrangement of the embedded MNPs. A naturally occurring solution to this problem is found in magnetotactic bacteria, which build chains of MNPs in a linear-chain formation in their cells to create a permanent magnetic dipole moment. This dipole moment enables them to actively sense magnetic fields and coordinate their movement in response, a behavior called magnetotaxis. Inspired by this, self-folding micro-origami swimmers comprising magnetic nanocomposite bilayer structures that exhibit controllable shape transformations and programmable, shape-independent magnetotaxis is fabricated. A study of these structures reveals that their magnetic anisotropy results from competition or cooperation between anisotropy of assembled chains of MNPs and overall shape anisotropy. Moreover, how the magnetotaxis of the reconfigurable micro-origami swimmers depends only on the embedded permanent dipole moment, independent of the overall magnetic anisotropy, is demonstrated.

Precise catheter control is crucial to the success of radiofrequency cardiac arrhythmia ablations. Remote control using external magnetic fields to directly steer the catheter tip is a promising strategy to accurately and easily perform cardiac catheter steering. Magnetic catheters must be flexible enough to be deflected by a magnetic field but rigid enough to provide sufficient force and stability during ablation. These conflicting requirements have limited the design options and effectiveness of magnetic catheters. Furthermore, the ablation force achievable by magnetic catheters depends strongly on the catheter's bending angle; at angles greater than 90°, it can be very difficult to achieve any significant force during ablation. To overcome these shortcomings, we propose to magnetically control a flexible segment at the distal tip of the introducer sheath, rather than the catheter. Control of the tip orientation is thus decoupled from catheter insertion, enabling more robust and intuitive manipulability of the catheter. Usability testing with the Aeon Phocus, a magnetic navigation system, has shown that the control of this magnetic sheath is indeed more intuitive than the control of a standard magnetic catheter.

In this paper linear control techniques are applied to a novel Omnicopter MAV design. This design is unique in its ability to withstand external disturbance and translate horizontally with more stable attitude. A dynamic model of the Omnicopter MAV has been developed using the Newton-Euler formalism. Based on a linearized version of the model with a fixed vertical ducted fan angle configuration, three different control schemes, namely PD control, Lyapunov-based control and optimal LQ control have been designed and proposed. Comparisons and relations between the three control schemes are discussed and simulations are presented. Finally, details on the Omnicopter prototype and initial test flights are presented. Controlled flights with vertical take-offs and landings have been achieved utilizing the PD control scheme.

In this paper, we present the design of the Omnicopter, a micro aerial vehicle (MAV) with two central counter-rotating coaxial propellers for thrust and yaw control and three perimeter-mounted variable angle ducted fans to control roll and pitch. First, a dynamic model of the robot is established using the Euler-Lagrange formalism. Next, we focus on the attitude control for a special operating case of the Omnicopter with fixed vertical positions of the surrounding ducted fans. A nonlinear model is represented in state space using the quaternion and angular velocity as state variables, which simplifies the system dynamics. Based on this model, a feedback linearization controller is developed, which renders the system linear and controllable from an input-output point of view. The zero dynamics problem is also analyzed. Finally, simulations are carried out and the results illustrate that the attitude stabilization task for the Omnicopter is achieved.

This paper presents the design, analysis, and performance results for a mobile microrobot that was designed for competing in the 2010 NIST Mobile Microrobot Challenge. Inspired by a crab-like micro robot driven by pulsating cardiomyocyte cells, an asymmetrically dimensioned magnetostrictive thin film bimorph microrobot has been designed. Utilizing the magnetostrictive principle, different bending and blocking forces occur under the robot's feet due to the in-plane strain generated in the bimorphs by the application of external magnetic fields in the workspace of the microrobot. The differences in the resulting frictional forces drive the movement of the robot body. To calculate and simulate whether the feet of the robot can generate enough force for locomotion, the design was abstracted and translated into a piezoelectric cantilever FEM model. The results are consistent with the magnetostrictive theoretical equations. Microrobot fabrication and test-bed development based on this analysis is shown along with experimental results validating this approach. Finally, a discussion of the performance results and recommendations for future improvements are provided.

Magnetic principles have proved successful for untethered submillimeter microrobotics, although challenges still exist in areas of propulsion and control. This paper presents the design, analysis, and performance results for a bimorph thin film magnetic microrobot utilizing the magnetostrictive principle as a secondary oscillating operation mode. The microrobot is no larger than 580 μm in its planar dimension and its total thickness is less than 5 μm. As a robot with magnetic material, it can be operated in a pushing/pulling mode in orthogonal directions for movement in a plane, while it's powered with an external magnetic field as low as 1 mT. For the secondary oscillating operation mode utilizing the magnetostrictive principle, in-plane strain is induced, resulting in bending and blocking forces on the robot. These forces are theoretically calculated to prove enough drive force can be generated in this mode. The design is further abstracted and translated into a piezoelectric cantilever FEM model to confirm the theorectical results. Microrobot fabrication and test-bed development based on this analysis is shown, which enabled us to participate in the final competition in the 2010 NIST Mobile Microrobot Challenge, with good performance in the dash and freestyle events. Finally, we discuss the testing results in various dry and fluid environments along with recommendations for future investigation and improvements. Keywords: microrobot, magnetostrictive, bimorph.