164 results
(View BibTeX file of all listed publications)
2022
Optoacoustic Tracking and Magnetic Manipulation of Cell-Sized Microrobots in Mice
Wrede, P., Degtyaruk, O., Kalva, S. K., Deán-Ben, X. L., Bozuyuk, U., Aghakhani, A., Akolpoglu, B., Sitti, M., Razansky, D.
Clinical and Translational Biophotonics, pages: TTu4B-6, 2022 (conference)
2021
Method of making one or more fibrils, computer implemented method of simulating an adhesive force of one or more fibrils and fibril
2021, EP Prio. Patent App. 21 162 253.5 (mpi_year_book)
Scientific Report 2016 - 2021
2021 (mpi_year_book)
This report presents research done at the Max Planck Institute for Intelligent Systems from January2016 to November 2021. It is our fourth report since the founding of the institute in 2011. Dueto the fact that the upcoming evaluation is an extended one, the report covers a longer reportingperiod.This scientific report is organized as follows: we begin with an overview of the institute, includingan outline of its structure, an introduction of our latest research departments, and a presentationof our main collaborative initiatives and activities (Chapter1). The central part of the scientificreport consists of chapters on the research conducted by the institute’s departments (Chapters2to6) and its independent research groups (Chapters7 to24), as well as the work of the institute’scentral scientific facilities (Chapter25). For entities founded after January 2016, the respectivereport sections cover work done from the date of the establishment of the department, group, orfacility. These chapters are followed by a summary of selected outreach activities and scientificevents hosted by the institute (Chapter26). The scientific publications of the featured departmentsand research groups published during the 6-year review period complete this scientific report.
2020
Learning of sub-optimal gait controllers for magnetic walking soft millirobots
Culha, U., Demir, S. O., Trimpe, S., Sitti, M.
In Robotics: Science and Systems XVI, pages: P070, (Editors: Toussaint, Marc and Bicchi, Antonio and Hermans, Tucker), RSS Foundation, Robotics: Science and Systems 2020 (RSS 2020), 2020 (inproceedings)
Untethered small-scale soft robots have promising applications in minimally invasive surgery, targeted drug delivery, and bioengineering applications as they can access confined spaces in the human body. However, due to highly nonlinear soft continuum deformation kinematics, inherent stochastic variability during fabrication at the small scale, and lack of accurate models, the conventional control methods cannot be easily applied. Adaptivity of robot control is additionally crucial for medical operations, as operation environments show large variability, and robot materials may degrade or change over time,which would have deteriorating effects on the robot motion and task performance. Therefore, we propose using a probabilistic learning approach for millimeter-scale magnetic walking soft robots using Bayesian optimization (BO) and Gaussian processes (GPs). Our approach provides a data-efficient learning scheme to find controller parameters while optimizing the stride length performance of the walking soft millirobot robot within a small number of physical experiments. We demonstrate adaptation to fabrication variabilities in three different robots and to walking surfaces with different roughness. We also show an improvement in the learning performance by transferring the learning results of one robot to the others as prior information.
Towards 5-DoF control of an untethered magnetic millirobot via MRI gradient coils
In 2020 IEEE International Conference on Robotics and Automation (ICRA 2020), pages: 6551-6557, IEEE, Piscataway, NJ, IEEE International Conference on Robotics and Automation (ICRA 2020), 2020 (inproceedings)
Design and Development of a Lorentz Force-Based MRI-Driven Neuroendoscope
Phelan III, M. F., Dogan, N. O., Lazovic, J., Sitti, M.
In 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 9534-9541, 2020 (inproceedings)
2019
Collective formation and cooperative function of a magnetic microrobotic swarm
IEEE, Robotics: Science and Systems, June 2019 (conference)
Untethered magnetically actuated microrobots can access distant, enclosed and small spaces, such as inside microfluidic channels and the human body, making them appealing for minimal invasive tasks. Despite the simplicity of individual magnetic microrobots, a collective of these
microrobots that can work closely and cooperatively would significantly enhance their capabilities. However, a challenge of realizing such collective magnetic microrobots is to coordinate their formations and motions with underactuated control signals. Here, we report a method that allows collective magnetic microrobots working closely and cooperatively by controlling their two-dimensional (2D) formations and collective motions in a programmable manner. The actively designed formation and intrinsic adjustable compliance within the group allow bio-inspired collective behaviors, such as navigating through cluttered environments and reconfigurable cooperative manipulation ability. These collective magnetic microrobots thus could enable potential applications in programmable self-assembly, modular robotics, swarm robotics, and biomedicine.
A magnetically-actuated untethered jellyfish-inspired soft milliswimmer
(Best Paper Award)
Robotics: Science and Systems, June 2019 (conference)
Wide range-sensitive, bending-insensitive pressure detection and application to wearable healthcare device
Kim, S., Amjadi, M., Lee, T., Jeong, Y., Kwon, D., Kim, M. S., Kim, K., Kim, T., Oh, Y. S., Park, I.
In 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), 2019 (inproceedings)
Scientific Report 2016 - 2018
2019 (mpi_year_book)
This report presents research done at the Max Planck Institute for Intelligent Systems from
January 2016 to December 2018. It is our third report since the founding of the institute in 2011.
This status report is organized as follows: we begin with an overview of the institute, including
its organizational structure (Chapter 1). The central part of the scientific report consists of chapters
on the research conducted by the institute’s departments (Chapters 2 to 5) and its independent
research groups (Chapters 6 to 18), as well as the work of the institute’s central scientific facilities
(Chapter 19). For entities founded after January 2016, the respective report sections cover work
done from the date of the establishment of the department, group, or facility.
Printing-while-moving: a new paradigm for large-scale robotic 3D printing
Tiryaki, M. E., Zhang, X., Pham, Q.
2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2019), pages: 2286-2291 , IEEE, Piscataway, NJ, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2019), 2019 (conference)
A bio-inspired robotic fish fin with mechanosensation using conductive liquid-metal-infused soft actuators
Liu, Z., Sun, W., Ren, Z., Hu, K., Wang, T., Wen, L.
2019 IEEE 9th Annual International Conference on CYBER Technology in Automation, Control, and Intelligent Systems (CYBER 2019), pages: 689-694, IEEE, Piscataway, NJ, IEEE 9th Annual International Conference on CYBER Technology in Automation, Control, and Intelligent Systems (CYBER 2019) , 2019 (conference)
2018
Enhanced non-steady gliding performance of the MultiMo-Bat through optimal airfoil configuration and control strategy
In 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 1382-1388, 2018 (inproceedings)
Collectives of spinning mobile microrobots for navigation and object manipulation at the air-water interface
Wang, W., Kishore, V., Koens, L., Lauga, E., Sitti, M.
In 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 1-9, 2018 (inproceedings)
Endo-VMFuseNet: A deep visual-magnetic sensor fusion approach for endoscopic capsule robots
Turan, M., Almalioglu, Y., Gilbert, H. B., Sari, A. E., Soylu, U., Sitti, M.
In 2018 IEEE International Conference on Robotics and Automation (ICRA), pages: 1-7, 2018 (inproceedings)
Endosensorfusion: particle filtering-based multi-sensory data fusion with switching state-space model for endoscopic capsule robots
Turan, M., Almalioglu, Y., Gilbert, H., Araujo, H., Cemgil, T., Sitti, M.
In 2018 IEEE International Conference on Robotics and Automation (ICRA), pages: 1-8, 2018 (inproceedings)
2017
Swimming in low reynolds numbers using planar and helical flagellar waves
Khalil, I. S. M., Tabak, A. F., Seif, M. A., Klingner, A., Adel, B., Sitti, M.
In 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 1907-1912, International Conference on Intelligent Robots and Systems, September 2017 (inproceedings)
In travelling towards the oviducts, sperm cells undergo transitions between planar to helical flagellar propulsion by a beating tail based on the viscosity of the environment. In this work, we aim to model and mimic this behaviour in low Reynolds number fluids using externally actuated soft robotic sperms. We numerically investigate the effects of transition between planar to helical flagellar propulsion on the swimming characteristics of the robotic sperm using a model based on resistive-force theory to study the role of viscous forces on its flexible tail. Experimental results are obtained using robots that contain magnetic particles within the polymer matrix of its head and an ultra-thin flexible tail. The planar and helical flagellar propulsion are achieved using in-plane and out-of-plane uniform fields with sinusoidally varying components, respectively. We experimentally show that the swimming speed of the robotic sperm increases by a factor of 1.4 (fluid viscosity 5 Pa.s) when it undergoes a controlled transition between planar to helical flagellar propulsion, at relatively low actuation frequencies.
An XY θz flexure mechanism with optimal stiffness properties
Lum, G. Z., Pham, M. T., Teo, T. J., Yang, G., Yeo, S. H., Sitti, M.
In 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), pages: 1103-1110, July 2017 (inproceedings)
The development of optimal XY θz flexure mechanisms, which can deliver high precision motion about the z-axis, and along the x- and y-axes is highly desirable for a wide range of micro/nano-positioning tasks pertaining to biomedical research, microscopy technologies and various industrial applications. Although maximizing the stiffness ratios is a very critical design requirement, the achievable translational and rotational stiffness ratios of existing XY θz flexure mechanisms are still restricted between 0.5 and 130. As a result, these XY θz flexure mechanisms are unable to fully optimize their workspace and capabilities to reject disturbances. Here, we present an optimal XY θz flexure mechanism, which is designed to have maximum stiffness ratios. Based on finite element analysis (FEA), it has translational stiffness ratio of 248, rotational stiffness ratio of 238 and a large workspace of 2.50 mm × 2.50 mm × 10°. Despite having such a large workspace, FEA also predicts that the proposed mechanism can still achieve a high bandwidth of 70 Hz. In comparison, the bandwidth of similar existing flexure mechanisms that can deflect more than 0.5 mm or 0.5° is typically less than 45 Hz. Hence, the high stiffness ratios of the proposed mechanism are achieved without compromising its dynamic performance. Preliminary experimental results pertaining to the mechanism's translational actuating stiffness and bandwidth were in agreement with the FEA predictions as the deviation was within 10%. In conclusion, the proposed flexure mechanism exhibits superior performance and can be used across a wide range of applications.
Positioning of drug carriers using permanent magnet-based robotic system in three-dimensional space
Khalil, I. S. M., Alfar, A., Tabak, A. F., Klingner, A., Stramigioli, S., Sitti, M.
In 2017 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), pages: 1117-1122, July 2017 (inproceedings)
Magnetic control of drug carriers using systems with open-configurations is essential to enable scaling to the size of in vivo applications. In this study, we demonstrate motion control of paramagnetic microparticles in a low Reynolds number fluid, using a permanent magnet-based robotic system with an open-configuration. The microparticles are controlled in three-dimensional (3D) space using a cylindrical NdFeB magnet that is fixed to the end-effector of a robotic arm. We develop a kinematic map between the position of the microparticles and the configuration of the robotic arm, and use this map as a basis of a closed-loop control system based on the position of the microparticles. Our experimental results show the ability of the robot configuration to control the exerted field gradient on the dipole of the microparticles, and achieve positioning in 3D space with maximum error of 300 µm and 600 µm in the steady-state during setpoint and trajectory tracking, respectively.
Self-assembly of micro/nanosystems across scales and interfaces
In 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), pages: 676 - 681, IEEE, July 2017 (inproceedings)
Steady progress in understanding and implementation are establishing self-assembly as a versatile, parallel and scalable approach to the fabrication of transducers. In this contribution, I illustrate the principles and reach of self-assembly with three applications at different scales - namely, the capillary self-alignment of millimetric components, the sealing of liquid-filled polymeric microcapsules, and the accurate capillary assembly of single nanoparticles - and propose foreseeable directions for further developments.
Dynamic analysis on hexapedal water-running robot with compliant joints
Kim, H., Liu, Y., Jeong, K., Sitti, M., Seo, T.
In 2017 14th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI), pages: 250-251, June 2017 (inproceedings)
The dynamic analysis has been considered as one of the important design methods to design robots. In this research, we derive dynamic equation of hexapedal water-running robot to design compliant joints. The compliant joints that connect three bodies will be used to improve mobility and stability of water-running motion's pitch behavior. We considered all of parts as rigid body including links of six Klann mechanisms and three main frames. And then, we derived dynamic equation by using the Lagrangian method with external force of the water. We are expecting that the dynamic analysis is going to be used to design parts of the water running robot.
Design and actuation of a magnetic millirobot under a constant unidirectional magnetic field
Erin, O., Giltinan, J., Tsai, L., Sitti, M.
In 2017 IEEE International Conference on Robotics and Automation (ICRA), 2017 IEEE International Conference on Robotics and Automation (ICRA), pages: 3404-3410, IEEE, Piscataway, NJ, USA, IEEE International Conference on Robotics and Automation (ICRA), May 2017 (inproceedings)
Magnetic untethered millirobots, which are actuated and controlled by remote magnetic fields, have been proposed for medical applications due to their ability to safely pass through tissues at long ranges. For example, magnetic resonance imaging (MRI) systems with a 3-7 T constant unidirectional magnetic field and 3D gradient coils have been used to actuate magnetic robots. Such magnetically constrained systems place limits on the degrees of freedom that can be actuated for untethered devices. This paper presents a design and actuation methodology for a magnetic millirobot that exhibits both position and orientation control in 2D under a magnetic field, dominated by a constant unidirectional magnetic field as found in MRI systems. Placing a spherical permanent magnet, which is free to rotate inside the millirobot and located away from the center of mass, allows the generation of net forces and torques with applied 3D magnetic field gradients. We model this system in a 3D planar case and experimentally demonstrate open-loop control of both position and orientation by the applied 2D field gradients. The actuation performance is characterized across the most important design variables, and we experimentally demonstrate that the proposed approach is feasible.
Magnetically actuated soft capsule endoscope for fine-needle aspiration biopsy
Son, D., Dogan, M. D., Sitti, M.
In Proceedings 2017 IEEE International Conference on Robotics and Automation (ICRA), pages: 1132-1139, IEEE, Piscataway, NJ, USA, 2017 IEEE International Conference on Robotics and Automation (ICRA), May 2017 (inproceedings)
This paper presents a magnetically actuated soft capsule endoscope for fine-needle aspiration biopsy (B-MASCE) in the upper gastrointestinal tract. A thin and hollow needle is attached to the capsule, which can penetrate deeply into tissues to obtain subsurface biopsy sample. The design utilizes a soft elastomer body as a compliant mechanism to guide the needle. An internal permanent magnet provides a means for both actuation and tracking. The capsule is designed to roll towards its target and then deploy the biopsy needle in a precise location selected as the target area. B-MASCE is controlled by multiple custom-designed electromagnets while its position and orientation are tracked by a magnetic sensor array. In in vitro trials, B-MASCE demonstrated rolling locomotion and biopsy of a swine tissue model positioned inside an anatomical human stomach model. It was confirmed after the experiment that a tissue sample was retained inside the needle.
Planning spin-walking locomotion for automatic grasping of microobjects by an untethered magnetic microgripper
In 2017 IEEE International Conference on Robotics and Automation (ICRA), pages: 6612-6618, 2017 (inproceedings)
Most demonstrated mobile microrobot tasks so far have been achieved via pick-and-placing and dynamic trapping with teleoperation or simple path following algorithms. In our previous work, an untethered magnetic microgripper has been developed which has advanced functions, such as gripping objects. Both teleoperated manipulation in 2D and 3D have been demonstrated. However, it is challenging to control the magnetic microgripper to carry out manipulation tasks, because the grasping of objects so far in the literature relies heavily on teleoperation, which takes several minutes with even a skilled human expert. Here, we propose a new spin-walking locomotion and an automated 2D grasping motion planner for the microgripper, which enables time-efficient automatic grasping of microobjects that has not been achieved yet for untethered microrobots. In its locomotion, the microgripper repeatedly rotates about two principal axes to regulate its pose and move precisely on a surface. The motion planner could plan different motion primitives for grasping and compensate the uncertainties in the motion by learning the uncertainties and planning accordingly. We experimentally demonstrated that, using the proposed method, the microgripper could align to the target pose with error less than 0.1 body length and grip the objects within 40 seconds. Our method could significantly improve the time efficiency of micro-scale manipulation and have potential applications in microassembly and biomedical engineering.
2016
Steering control of a water-running robot using an active tail
Kim, H., Jeong, K., Sitti, M., Seo, T.
In Intelligent Robots and Systems (IROS), 2016 IEEE/RSJ International Conference on, pages: 4945-4950, October 2016 (inproceedings)
Many highly dynamic novel mobile robots have been developed being inspired by animals. In this study, we are inspired by a basilisk lizard's ability to run and steer on water surface for a hexapedal robot. The robot has an active tail with a circular plate, which the robot rotates to steer on water. We dynamically modeled the platform and conducted simulations and experiments on steering locomotion with a bang-bang controller. The robot can steer on water by rotating the tail, and the controlled steering locomotion is stable. The dynamic modelling approximates the robot's steering locomotion and the trends of the simulations and experiments are similar, although there are errors between the desired and actual angles. The robot's maneuverability on water can be improved through further research.
Targeting of cell mockups using sperm-shaped microrobots in vitro
Khalil, I. S., Tabak, A. F., Hosney, A., Klingner, A., Shalaby, M., Abdel-Kader, R. M., Serry, M., Sitti, M.
In 2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics (BioRob), pages: 495-501, July 2016 (inproceedings)
Sperm-shaped microrobots are controlled under the influence of weak oscillating magnetic fields (milliTesla range) to selectively target cell mockups (i.e., gas bubbles with average diameter of 200 μm). The sperm-shaped microrobots are fabricated by electrospinning using a solution of polystyrene, dimethylformamide, and iron oxide nanoparticles. These nanoparticles are concentrated within the head of the microrobot, and hence enable directional control along external magnetic fields. The magnetic dipole moment of the microrobot is characterized (using the flip-time technique) to be 1.4×10-11 A.m2, at magnetic field of 28 mT. In addition, the morphology of the microrobot is characterized using Scanning Electron Microscopy images. The characterized parameters and morphology are used in the simulation of the locomotion mechanism of the microrobot to prove that its motion depends on breaking the time-reversal symmetry, rather than pulling with the magnetic field gradient. We experimentally demonstrate that the microrobot can controllably follow S-shaped, U-shaped, and square paths, and selectively target the cell mockups using image guidance and under the influence of the oscillating magnetic fields.
Analysis of the magnetic torque on a tilted permanent magnet for drug delivery in capsule robots
Munoz, F., Alici, G., Zhou, H., Li, W., Sitti, M.
In 2016 IEEE International Conference on Advanced Intelligent Mechatronics (AIM), pages: 1386-1391, July 2016 (inproceedings)
In this paper, we present the analysis of the torque transmitted to a tilted permanent magnet that is to be embedded in a capsule robot to achieve targeted drug delivery. This analysis is carried out by using an analytical model and experimental results for a small cubic permanent magnet that is driven by an external magnetic system made of an array of arc-shaped permanent magnets (ASMs). Our experimental results, which are in agreement with the analytical results, show that the cubic permanent magnet can safely be actuated for inclinations lower than 75° without having to make positional adjustments in the external magnetic system. We have found that with further inclinations, the cubic permanent magnet to be embedded in a drug delivery mechanism may stall. When it stalls, the external magnetic system's position and orientation would have to be adjusted to actuate the cubic permanent magnet and the drug release mechanism. This analysis of the transmitted torque is helpful for the development of real-time control strategies for magnetically articulated devices.
Sperm-shaped magnetic microrobots: Fabrication using electrospinning, modeling, and characterization
Khalil, I. S., Tabak, A. F., Hosney, A., Mohamed, A., Klingner, A., Ghoneima, M., Sitti, M.
In 2016 IEEE International Conference on Robotics and Automation (ICRA), pages: 1939-1944, May 2016 (inproceedings)
We use electrospinning to fabricate sperm-shaped magnetic microrobots with a range of diameters from 50 μm to 500 μm. The variables of the electrospinning operation (voltage, concentration of the solution, dynamic viscosity, and distance between the syringe needle and collector) to achieve beading effect are determined. This beading effect allows us to fabricate microrobots with similar morphology to that of sperm cells. The bead and the ultra-fine fiber resemble the morphology of the head and tail of the sperm cell, respectively. We incorporate iron oxide nanoparticles to the head of the sperm-shaped microrobot to provide a magnetic dipole moment. This dipole enables directional control under the influence of external magnetic fields. We also apply weak (less than 2 mT) oscillating magnetic fields to exert a magnetic torque on the magnetic head, and generate planar flagellar waves and flagellated swim. The average speed of the sperm-shaped microrobot is calculated to be 0.5 body lengths per second and 1 body lengths per second at frequencies of 5 Hz and 10 Hz, respectively. We also develop a model of the microrobot using elastohydrodynamics approach and Timoshenko-Rayleigh beam theory, and find good agreement with the experimental results.
Cell patterning in a hydrogel using optically induced dielectrophoresis
Hu, W., Ishii, K., Ohta, A. T.
In Optical MEMS and Nanophotonics (OMN), 2016 International Conference on, pages: 1-2, 2016 (inproceedings)
2015
Compliant wing design for a flapping wing micro air vehicle
Colmenares, D., Kania, R., Zhang, W., Sitti, M.
In Intelligent Robots and Systems (IROS), 2015 IEEE/RSJ International Conference on, pages: 32-39, September 2015 (inproceedings)
In this work, we examine several wing designs for a motor-driven, flapping-wing micro air vehicle capable of liftoff. The full system consists of two wings independently driven by geared pager motors that include a spring in parallel with the output shaft. The linear transmission allows for resonant operation, while control is achieved by direct drive of the wing angle. Wings used in previous work were chosen to be fully rigid for simplicity of modeling and fabrication. However, biological wings are highly flexible and other micro air vehicles have successfully utilized flexible wing structures for specialized tasks. The goal of our study is to determine if wing flexibility can be generally used to increase wing performance. Two approaches to lift improvement using flexible wings are explored, resonance of the wing cantilever structure and dynamic wing twisting. We design and test several wings that are compared using different figures of merit. A twisted design improved lift per power by 73.6% and maximum lift production by 53.2% compared to the original rigid design. Wing twist is then modeled in order to propose optimal wing twist profiles that can maximize either wing efficiency or lift production.
Millimeter-scale magnetic swimmers using elastomeric undulations
Zhang, J., Diller, E.
In 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 1706-1711, September 2015 (inproceedings)
This paper presents a new soft-bodied millimeterscale swimmer actuated by rotating uniform magnetic fields. The proposed swimmer moves through internal undulatory deformations, resulting from a magnetization profile programmed into its body. To understand the motion of the swimmer, a mathematical model is developed to describe the general relationship between the deflection of a flexible strip and its magnetization profile. As a special case, the situation of the swimmer on the water surface is analyzed and predictions made by the model are experimentally verified. Experimental results show the controllability of the proposed swimmer under a computer vision-based closed-loop controller. The swimmers have nominal dimensions of 1.5×4.9×0.06 mm and a top speed of 50 mm/s (10 body lengths per second). Waypoint following and multiagent control are demonstrated for swimmers constrained at the air-water interface and underwater swimming is also shown, suggesting the promising potential of this type of swimmer in biomedical and microfluidic applications.
Fiberbot: A miniature crawling robot using a directional fibrillar pad
Han, Y., Marvi, H., Sitti, M.
In Robotics and Automation (ICRA), 2015 IEEE International Conference on, pages: 3122-3127, May 2015 (inproceedings)
Vibration-driven locomotion has been widely used for crawling robot studies. Such robots usually have a vibration motor as the actuator and a fibrillar structure for providing directional friction on the substrate. However, there has not been any studies about the effect of fiber structure on robot crawling performance. In this paper, we develop Fiberbot, a custom made mini vibration robot, for studying the effect of fiber angle on robot velocity, steering, and climbing performance. It is known that the friction force with and against fibers depends on the fiber angle. Thus, we first present a new fabrication method for making millimeter scale fibers at a wide range of angles. We then show that using 30° angle fibers that have the highest friction anisotropy (ratio of backward to forward friction force) among the other fibers we fabricated in this study, Fiberbot speed on glass increases to 13.8±0.4 cm/s (compared to ν = 0.6±0.1 cm/s using vertical fibers). We also demonstrate that the locomotion direction of Fiberbot depends on the tilting direction of fibers and we can steer the robot by rotating the fiber pad. Fiberbot could also climb on glass at inclinations of up to 10° when equipped with fibers of high friction anisotropy. We show that adding a rigid tail to the robot it can climb on glass at 25° inclines. Moreover, the robot is able to crawl on rough surfaces such as wood (ν = 10.0±0.2 cm/s using 30° fiber pad). Fiberbot, a low-cost vibration robot equipped with a custom-designed fiber pad with steering and climbing capabilities could be used for studies on collective behavior on a wide range of topographies as well as search and exploratory missions.
Platform design and tethered flight of a motor-driven flapping-wing system
Hines, L., Colmenares, D., Sitti, M.
In Robotics and Automation (ICRA), 2015 IEEE International Conference on, pages: 5838-5845, May 2015 (inproceedings)
In this work, we examine two design modifications to a tethered motor-driven flapping-wing system. Previously, we had demonstrated a simple mechanism utilizing a linear transmission for resonant operation and direct drive of the wing flapping angle for control. The initial two-wing system had a weight of 2.7 grams and a maximum lift-to-weight ratio of 1.4. While capable of vertical takeoff, in open-loop flight it demonstrated instability and pitch oscillations at the wing flapping frequency, leading to flight times of only a few wing strokes. Here the effect of vertical wing offset as well as an alternative multi-wing layout is investigated and experimentally tested with newly constructed prototypes. With only a change in vertical wing offset, stable open-loop flight of the two-wing flapping system is shown to be theoretically possible, but difficult to achieve with our current design and operating parameters. Both of the new two and four-wing systems, however, prove capable of flying to the end of the tether, with the four-wing system prototype eliminating disruptive wing beat oscillations.
2014
Geckogripper: A soft, inflatable robotic gripper using gecko-inspired elastomer micro-fiber adhesives
Song, S., Majidi, C., Sitti, M.
In Intelligent Robots and Systems (IROS 2014), 2014 IEEE/RSJ International Conference on, pages: 4624-4629, September 2014 (inproceedings)
This paper proposes GeckoGripper, a novel soft, inflatable gripper based on the controllable adhesion mechanism of gecko-inspired micro-fiber adhesives, to pick-and-place complex and fragile non-planar or planar parts serially or in parallel. Unlike previous fibrillar structures that use peel angle to control the manipulation of parts, we developed an elastomer micro-fiber adhesive that is fabricated on a soft, flexible membrane, increasing the adaptability to non-planar three-dimensional (3D) geometries and controllability in adhesion. The adhesive switching ratio (the ratio between the maximum and minimum adhesive forces) of the developed gripper was measured to be around 204, which is superior to previous works based on peel angle-based release control methods. Adhesion control mechanism based on the stretch of the membrane and superior adaptability to non-planar 3D geometries enable the micro-fibers to pick-and-place various 3D parts as shown in demonstrations.
Three-dimensional robotic manipulation and transport of micro-scale objects by a magnetically driven capillary micro-gripper
Giltinan, J., Diller, E., Mayda, C., Sitti, M.
In Robotics and Automation (ICRA), 2014 IEEE International Conference on, pages: 2077-2082, 2014 (inproceedings)
Liquid-metal reconfigurable RF components and antennas
Dang, J. H., Morishita, A. M., Gough, R. C., Hu, W., Ohta, A. T., Shiroma, W. A.
In Radio Science Meeting (USNC-URSI NRSM), 2014 United States National Committee of URSI National, pages: 1-1, 2014 (inproceedings)
Robotic assembly of hydrogels for tissue engineering and regenerative medicine
Tasoglu, S, Diller, E, Guven, S, Sitti, M, Demirci, U
In Journal of Tissue Engineering and Regenerative Medicine, 8, pages: 181-182, 2014 (inproceedings)
Molecular delivery and transfection by laser-induced oscillating microbubbles
Fan, Q., Hu, W., Ohta, A. T.
In Nano/Micro Engineered and Molecular Systems (NEMS), 2014 9th IEEE International Conference on, pages: 302-305, 2014 (inproceedings)
Versatile non-contact micro-manipulation method using rotational flows locally induced by magnetic microrobots
Ye, Z., Edington, C., Russell, A. J., Sitti, M.
In Advanced Intelligent Mechatronics (AIM), 2014 IEEE/ASME International Conference on, pages: 26-31, 2014 (inproceedings)
Structural optimization method towards synthesis of small scale flexure-based mobile grippers
Lum, G. Z., Diller, E., Sitti, M.
In Robotics and Automation (ICRA), 2014 IEEE International Conference on, pages: 2339-2344, 2014 (inproceedings)
Six-Degrees-of-Freedom Remote Actuation of Magnetic Microrobots.
Diller, E. D., Giltinan, J., Lum, G. Z., Ye, Z., Sitti, M.
In Robotics: Science and Systems, 2014 (inproceedings)
2013
Angular Motion Control Using a Closed-Loop CPG for a Water-Running Robot
Thatte, N., Khoramshahi, M., Ijspeert, A., Sitti, M.
In Dynamic Walking 2013, (EPFL-CONF-199763), 2013 (inproceedings)
A hybrid topological and structural optimization method to design a 3-DOF planar motion compliant mechanism
Lum, G. Z., Teo, T. J., Yang, G., Yeo, S. H., Sitti, M.
In Advanced Intelligent Mechatronics (AIM), 2013 IEEE/ASME International Conference on, pages: 247-254, 2013 (inproceedings)
Light-induced microbubble poration of localized cells
Fan, Qihui, Hu, Wenqi, Ohta, Aaron T
In Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE, pages: 4482-4485, 2013 (inproceedings)
SoftCubes: towards a soft modular matter
Yim, S., Sitti, M.
In Robotics and Automation (ICRA), 2013 IEEE International Conference on, pages: 530-536, 2013 (inproceedings)
Bubble-driven light-absorbing hydrogel microrobot for the assembly of bio-objects
Hu, W., Fan, Q., Tonaki, W., Ohta, A. T.
In Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE, pages: 5303-5306, 2013 (inproceedings)
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