A Swashplateless MAV: Thrust, Roll, Pitch, and Yaw from Only Two Motors Modlab UPenn 2014-10-23 | A Swashplateless MAV: Thrust, Roll, Pitch, and Yaw from Only Two MotorsWe derive thrust, roll, and pitch authority from a single propeller and single motor through an underactuated mechanism embedded in the rotor itself. This allows new types of conventionally-capable micro air vehicles which only require two motors for practical control. This contrasts with the many servos and linkages of conventional helicopters or the many drive motors found in quadrotors.This is an ongoing research project of James Paulos, one of Prof. Mark Yim's students at the University of Pennsylvania.We are the Modlab, a part of the GRASP Robotics lab. Visit our website at http://modlabupenn.org for more pictures, videos, and links to our research papers.
Motion Planning for Variable Topology Trusses: Reconfiguration and Locomotion Modlab UPenn 2023-09-25 | Variable Topology Truss is a class of self-reconfigurable modular robots that are in truss structure. These robots are promising for a variety of tasks due to its flexibility. We present a framework to do motion planning for these robots, including reconfiguration and locomotion. More information can be found here: modlabupenn.org/vtt-motion-planning/.
ICRA 2023 Presentation: Multi-Robot Coordination and Cooperation with Task Precedence Relationships Modlab UPenn 2023-05-21 | Full paper here: arxiv.org/abs/2209.14417This short video accompanies our paper at ICRA 2023 in London! We present a novel task allocation framework that models the multi-robot task allocation problem more richly, and introduces graph-based solution methods that can solve large problems many times faster than previous work!
A Linking Invariant for Truss Robot Motion Planning - ICRA 2022 Modlab UPenn 2023-05-14 | This talk presents the paper "A Linking Invariant for Truss Robot Motion Planning," which was published in RAL/ICRA2022.Speaker: Alexander Spinos
Docking in a Flow - Simulation #2 Modlab UPenn 2023-03-06 | This video accompanies the paper "Flow-Based Rendezvous and Docking for Marine Modular Robots in Gyre-Like Environments". It demonstrates a simulated experiment in a Rankine Vortex where both the naive and flow-based approaches succeed. The naive approach succeeds more quickly, but is more expensive.
Flow-Based Rendezvous and Docking - Simulation #1 Modlab UPenn 2023-03-06 | This video accompanies the paper "Flow-Based Rendezvous and Docking for Marine Modular Robots in Gyre-Like Environments". It demonstrates a simulated experiment in a Rankine Vortex where the naive approach fails, while the flow-based approach succeeds.
Modboats Collective Movement Demo Modlab UPenn 2022-07-29 | Modboats are capable of collective swimming in arbitrary configurations! In this video you can see three different configurations of the Modboats swim across our test space and demonstrate their capabilities.
Quori: A Community-Informed Design of a Socially Interactive Humanoid Robot Modlab UPenn 2022-06-01 | ICRA 2022 presentation for our T-RO Journal Paper on Quori:DOI 10.1109/TRO.2021.3111718
Amplitude Control for Parallel Lattices of Docked Modboats - ICRA 2022 Presentation Modlab UPenn 2022-05-31 | 4 minute lightning talk presenting our paper "Amplitude Control forParallel Lattices of Docked Modboats" at ICRA 2022.
Modboats: Desaturated Thrust Direction Control (DTD) Modlab UPenn 2022-02-16 | The Modboat -despite having only one motor - can act like a pointable thruster when controlled using desaturated thrust direction control, discussed in our work: Thrust Direction Control of an Underactuated Oscillating Swimming Robot (ieeexplore.ieee.org/document/9636778). This makes it incredibly maneuverable, and this video demonstrates the Modboat executing a picture-perfect square trajectory.
Modboat docking demo Modlab UPenn 2022-02-16 | A single mobile Modboat docks to a static target Modboat, demonstrating our approach strategy. The final docking is in a 90 degree rotated position, so the Modboat executes a quarter turn in the moments before the docking occurs.
Finding Structure Configurations for Flying Modular Robots, IROS 2021 (presentation) Modlab UPenn 2021-11-18 | Finding Structure Configurations for Flying Modular Robots Bruno Gabrich, David Saldaña, Mark Yim
Thrust Direction Control of an Underactuated Oscillating Swimming Robot (Experimental Demo) Modlab UPenn 2021-10-01 | Experimental results video accompanying the paper "Thrust Direction Control of an Underactuated Oscillating Swimming Robot ," by Gedaliah Knizhnik and Mark Yim, which is published in the IROS2021 Proceedings.You can find a pre-print of the full work on arXiv: arxiv.org/abs/2107.13055. It will be available on IEEE Xplore soon!
Thrust Direction Control of an Underactuated Oscillating Swimming Robot @ IROS 2021 Modlab UPenn 2021-09-30 | Presentation given at the virtual IROS2021 conference for the paper "Thrust Direction Control of an Underactuated Oscillating Swimming Robot," by Gedaliah Knizhnik and Mark Yim. The manuscript is available on arXiv: arxiv.org/abs/2107.13055
Modboat underview - how one motor creates propulsion and steering Modlab UPenn 2021-09-13 | A demonstration of how the Modboat swims. A single motor oscillates the two linked bodies, and fluid forces cause the two flippers to open in series in a paddling motion. We can vary the paddling motion to create propulsion and steering in various ways. In this setup the Modboat is artificially constrained such that it can rotate but not translate.
Finding Structure Configurations for Flying Modular Robots, IROS 2021 Modlab UPenn 2021-08-13 | Flying Modular Structures offer a versatile mechanism that can change the arrangement of constituent actuators according to task requirements. In this work, we extend a modular aerial platform that can expand its actuation capabilities depending on the configuration. Each module is composed of a quadrotor in a cage that can rigidly connect with other modules. The quadrotor is connected with the cage by a revolute joint that allows it to rotate with respect to the cage. Modules located in the structure are either parallel or perpendicular to one another. The task specification defines forces and moments needed during the execution. We propose two search methods to find a configuration that can satisfy the specification. The first approach consists of an exhaustive search that yields optimal structure configurations by exploring the whole search space. The second approach proposes a heuristic based on subgroup search, reducing the problem complexity from exponential to linear. We validate our proposed algorithms with several simulations. Our results show that the proposed heuristic is computationally efficient and finds a near-optimal configuration even for flying modular structures composed of a large number of modules.Bruno Gabrich, David Saldaña, and Mark YimFor more specific information: modlabupenn.org/2021/08/13/finding-structure-configurations-for-flying-modular-structuresp.s. work to be presented at IROS 2021
Manipulation in Real-Time Using Modular Robots Modlab UPenn 2021-07-07 | Motion planning in high-dimensional space is a challenging task. In order to perform dexterous manipulation in an unstructured environment, a robot with many degrees of freedom is usually necessary, which also complicates its motion planning problem. We provide a real-time control and planning solution to handle this difficulty. The framework is demonstrated on modular robot morphologies which are usually redundant systems. More information can be found here: modlabupenn.org/2021/07/07/manipulation-in-real-time
Docking and Undocking a Modular Underactuated Oscillating Swimming Robot @ ICRA2021 Modlab UPenn 2021-06-04 | Presentation given at the hybrid ICRA2021 conference for the paper "Docking and Undocking a Modular Underactuated Oscillating Swimming Robot," by Gedaliah Knizhnik and Mark Yim, which is published in the ICRA2021 Proceedings.You can find a pre-print of the full work on arXiv: arxiv.org/abs/2102.12909. It will be available on IEEE Xplore soon!
Docking and Undocking a Modular Underactuated Oscillating Swimming Robot (Experimental Demo) Modlab UPenn 2021-06-04 | Experimental results video accompanying the paper "Docking and Undocking a Modular Underactuated Oscillating Swimming Robot," by Gedaliah Knizhnik and Mark Yim, which is published in the ICRA2021 Proceedings.You can find a pre-print of the full work on arXiv: arxiv.org/abs/2102.12909. It will be available on IEEE Xplore soon!
Pauses Provide Effective Control for an Underactuated Oscillating Swimming Robot @ IROS2020 Modlab UPenn 2020-10-27 | Presentation given at the virtual IROS2020 conference for the paper "Pauses Provide Effective Control for an Underactuated Oscillating Swimming Robot," by Gedaliah Knizhnik, Philip deZonia, and Mark Yim, which is published in the IEEE Robotics and Automation Letters (RA-L).The full work can be found on IEEE Xplore: ieeexplore.ieee.org/document/9127879DOI: 10.1109/LRA.2020.3005383
Motion Planning for Variable Topology Truss Modular Robot Modlab UPenn 2020-07-10 | Variable Topology Truss is a class of self-reconfigurable modular robots that are in truss structure. These robots are promising for a variety of tasks due to its flexibility. We present a framework to do motion planning for these robots, including geometry reconfiguration and topology reconfiguration. More information can be found here: modlabupenn.org/2020/06/03/motion-planning-for-variable-topology-truss-modular-robot
Design and Experiments with a Low-Cost Single-Motor Modular Aquatic Robot (UR 2020) Modlab UPenn 2020-06-21 | Video presentation of the paper "Design and Experiments with a Low-Cost Single-Motor Modular Aquatic Robot," by Gedaliah Knizhnik and Mark Yim. The paper was presented by Gedaliah Knizhnik at the 2020 Ubiquitous Robots (UR) Conference. A preprint copy of the paper can be found at arxiv.org/abs/2002.01918The finalized copy will be linked once the conference proceedings are published.
Pauses Provide Effective Control for an Underactuated Oscillating Swimming Robot (RA-L 2020) Modlab UPenn 2020-06-18 | Experimental results video accompanying the paper "Pauses Provide Effective Control for an Underactuated Oscillating Swimming Robot," by Gedaliah Knizhnik, Philip deZonia, and Mark Yim, which is published in the IEEE Robotics and Automation Letters (RA-L).The full work can be found on IEEE Xplore: ieeexplore.ieee.org/document/9127879DOI: 10.1109/LRA.2020.3005383
ModQuad-DoF: A Novel Yaw Actuation for Modular Quadrotors (ICRA 2020) Modlab UPenn 2020-06-03 | ICRA 2020 PresentationBruno Gabrich, Guanrui Li, and Mark Yim
Parallel Self-Assembly with SMORES-EP, a Modular Robot Modlab UPenn 2020-04-29 | Self-assembly of modular robotic systems enables the construction of complex robotic configurations to adapt to different tasks. This is inspired by the collective intelligence in nature that groups of individuals can form a variety of structures in order to overcome the limited capability of each individual. We present a framework for SMORES types of modular robots to efficiently self-reconfigure into kinematic topologies in tree structure. More information can be found here: modlabupenn.org/2020/04/29/parallel-self-assembly-with-smores-ep-a-modular-robot
A Fast Configuration Space Algorithm for Variable Topology Truss Modular Robots Modlab UPenn 2020-04-19 | The Variable Topology Truss (VTT) is a new class of self-reconfigurable robot that can reconfigure its truss shape and topology depending on the task or environment requirements. Motion planning and avoiding self-collision are difficult as these systems usually have dozens of degrees-of-freedom with complex intersecting parallel actuations. We present a fast algorithm to compute the configuration space of a node so that path planning can be done quickly using cell decomposition and graph search. Shape-morphing can be achieved by quickly moving one node at a time. More information can be found here: modlabupenn.org/2020/04/19/a-fast-configuration-space-algorithm-for-variable-topology-truss-modular-robots
ModQuad-DoF: A Novel Yaw Actuation for Modular Quadrotors Modlab UPenn 2020-03-06 | In this work we introduce ModQuad-DoF, a modular flying robotic structure with enhanced capabilities for yaw actuation. We propose a new module design that allows a one degree of freedom relative motion between the flying robot and the cage, with a docking mechanism allowing rigid connections between cages. A novel method of yaw actuation that increases the structure control authority is also presented. Our new method for the structure yaw control relies on the independent roll angles of each one of the modules, instead of the traditional drag moments from the propellers. In this paper, we propose a controller that allows the ModQuad-DoF to control its position and attitude. In our experiments, we tested a different number of modules flying in cooperation and validated the novel yaw actuation method.Bruno Gabrich, Guanrui li and Mark Yimp.s. work to be presented at ICRA 2020
Reconfiguration Motion Planning for Variable Topology Truss Modlab UPenn 2019-08-24 | Variable topology truss (VTT) is a new class of self-reconfigurable modular robot. We present a novel algorithm to do motion planning for VTT inspired by DNA replication process. Limited reconfiguration actions can be applied on nodes without regarding to internal collision. More details can be found here: modlabupenn.org/2019/08/08/reconfiguration-motion-planning-for-variable-topology-truss
Spiral Zipper Manipulator Modlab UPenn 2019-08-24 | We present a novel manipulator for aerial vehicles to perform grasping and manipulation tasks. The manipulator is low-cost, relatively light but strong with a large workspace and compact storage space that can be mounted on an unmanned aerial system. More details and relative publications can be found here: modlabupenn.org/2019/08/15/spiral-zipper-manipulator-for-aerial-grasping-and-manipulation
A Distributed Reconfiguration Planning Algorithm for Modular Robots Modlab UPenn 2019-07-22 | Self-reconfigurable modular robots are usually composed of multiple modules with uniform docking interfaces that can be transformed into different configurations by themselves. The reconfiguration planning problem is finding what sequence of reconfiguration actions are required for one arrangement of modules to transform into another. We present a novel reconfiguration planning algorithm for modular robots. More details can be found here: modlabupenn.org/2019/07/23/a-distributed-reconfiguration-planning-for-modular-robots
ModQuad-Vi: A Vision-Based Self-Assembling Modular Quadrotor Modlab UPenn 2019-03-13 | Flying modular robots have the potential to rapidly form temporary structures. In the literature, docking actions rely on external systems and indoor infrastructures for relative pose estimation. In contrast to related work, we provide local estimation during the self-assembly process to avoid dependency on external systems. In this paper, we introduce ModQuad-Vi, a flying modular robot that is aimed to operate in outdoor environments. We propose a new robot design and vision-based docking method. Our design is based on a quadrotor platform with onboard computation and visual perception. Our control method is able to accurately align modules for docking actions. Additionally, we present the dynamics and a geometric controller for the aerial modular system. Experiments validate the vision-based docking method with successful results.Guanrui Li, Bruno Gabrich, David Saldaña, Jnaneshwar Das, Vijay Kumar, and Mark Yim
A Fully Actuated Aerial Vehicle using Two Actuators Modlab UPenn 2018-05-30 | A "fully actuated" MAV using only two actuators: independent, simultaneous control over position and orientation.For more details, see our paper "Emulating a Fully Actuated Aerial Vehicle using Two Actuators" by James Paulos, Bennet Caraher, and Mark Yim.We are the Modlab, a part of the GRASP Robotics lab at the University of Pennsylvania. Visit our website at http://modlabupenn.org for more pictures, videos, and links to our research papers.
ModQuad: The Flying Structure that Self-Assembles in Midair - ICRA 2018 Modlab UPenn 2018-03-17 | We introduce ModQuad, a novel flying modular robotic structure that is able to self-assemble in midair and cooperatively fly. The structure is composed by agile flying modules that can easily move in a three dimensional environment. The module is based on a quadrotor platform within a cuboid frame which allows it to attach to other modules by matching vertical faces. Using this mechanism, a ModQuad swarm is able to rapidly assemble flying structures in midair using the robot bodies as building units. In this paper, we focus on two important tasks for modular flying structures.First, we propose a decentralized modular attitude controller to allow a team of physically connected modules to fly cooperatively. Second, we develop a docking method that drives pairs of structures to be attached in midair. Our method precisely aligns, and corrects motion errors during the docking process. In our experiments, we tested and analyzed the performance of the cooperative flying method for multiple configurations. We also tested the docking method with successful results.David Saldaña*, Bruno Gabrich*, Guanrui Li, Mark Yim, and Vijay Kumar*equal contributors
ModQuad Gripper - ICRA 2018 Modlab UPenn 2018-03-16 | We present a novel flying modular platform capable of grasping and transporting objects. It is composed of four cooperative identical modules where each is based on a quadrotor within a cuboid frame with a docking mechanism. Pairs of modules are able to fly independently and physically connect by matching their vertical edges forming a hinge. Four one degree of freedom (DOF) connections results in a one DOF four-bar linkage that can be used to grasp external objects. In this paper, we propose a decentralized method that allows the Flying Gripper to control its position, attitude and aperture angle. In our experiments, we tested the hovering performance for different aperture angles and with a grasped object. The performance for a closing and opening motion was also verified.Bruno Gabrich*, David Saldaña*, Vijay Kumar, and Mark Yim*equal contributors
Accomplishing Tasks with Modular Robots Modlab UPenn 2017-11-16 | Video accompanying the paper "Accomplishing Tasks with Modular Robots." Authors: Gangyuan Jing, Tarik Tosun, Mark Yim, and Hadas Kress-Gazit.
PaintPots: Low Cost, Accurate, Highly Customizable Potentiometers for Position Sensing Modlab UPenn 2017-10-25 | Video accompanying paper presented at ICRA 2017.
A Flying Gripper Based on Cuboid Modular Robots Modlab UPenn 2017-10-16 | We present a novel flying modular platform capable of grasping and transporting objects. It is composed of four cooperative identical modules where each is based on a quadrotor within a cuboid frame with a docking mechanism. Pair of modules are able to fly independently and physically connect by matching their vertical edges forming a hinge. Four one degree of freedom (DOF) connections results in a one DOF four-bar linkage that can be used to grasp external objects.Bruno Gabrich*, David Saldaña*, Vijay Kumar, and Mark Yim*equal contributors
ModQuad: The Flying Modular Structure that Self-Assembles in Midair Modlab UPenn 2017-10-16 | We introduce ModQuad, a novel flying modular robotic structure that is able to self-assemble in midair and cooperatively fly. The structure is composed by agile flying modules that can easily move in a three dimensional environment. The module is based on a quadrotor platform within a cuboid frame which allows it to attach to other modules by matching vertical faces. Using this mechanism, a ModQuad swarm is able to rapidly assemble flying structures in midair using the robot bodies as building units.David Saldaña*, Bruno Gabrich*, Guanrui Li, Mark Yim, and Vijay Kumar*equal contributors
Assembling Structures with Modular Robots - IROS17 Modlab UPenn 2017-10-16 | Recent work in the field of bio-inspired systems has introduced designs for modular robots that are able to assemble into structures (e.g., bridges, landing platforms, fences) using their bodies as the building components. Yet, it remains an open question as to how to program large swarms of robotic modules so that the assembly task is performed as efficiently as possible. Moreover, the problem of designing assembly algorithms is compounded by the scale of these systems, and the lack of centralized guidance in unstructured environments. The main contribution of this work is a decentralized algorithm to assemble structures with modular robots. Importantly, we coordinate the robots so that docking actions can be parallelized.
Piccolissimo Modlab UPenn 2016-10-27 | Piccolissimo is the smallest self-powered flying vehicle. It is passively stable, which lets us use only one motor. If we pulse its motor, which is offset from the center of mass, at the frequency of the body rotation, we can make a net torque that steers the vehicle. More info at http://modlabupenn.org/piccolissimo.
Anticogging: Torque ripple suppression, modeling, and parameter selection Modlab UPenn 2016-01-05 | More information at: http://modlabupenn.org/anticoggingLow cost brushless direct current motors are becoming more prevalent, especially from the hobby remote control community. These motors often have the required high-torque density; however, they also have significant torque ripple. This video and accompanying paper presents a low cost method for anticogging, the compensation of cogging torque.
Passive stability of MAVs Without Angular Momentum Modlab UPenn 2015-07-02 | We modeled and built Micro Aerial Vehicles (MAVs) that naturally hover without any sensing or control. These types of vehicles, called passively stabilized vehicles, can be made less complicated, more robust, and at lower cost with the addition of simple, yet carefully designed, stabilizer sails.
2015 AHS MAV Student Challenge Modlab UPenn 2015-06-09 | Students from the University of Pennsylvania participated in the 2015 AHS MAV Student Challenge in Virginia Beach, VA. Our readiness video demonstrates full cyclic control of our 38 gram swashplateless helicopter.At the competition, this vehicle was remotely piloted through the onboard camera during an indoor target search. The University of Pennsylvania was provided an honorable mention award of $1,500 for “Flying a vehicle which was an order of magnitude lighter than the other competitors, and having a novel means of control."Our team benefited from the resources and experience of Professor Mark Yim's Modlab, a part of the GRASP Robotics Laboratory at the University of Pennsylvania. Visit our website at http://modlabupenn.org for more pictures, videos, and links to our research papers.
Cogging Torque Ripple Minimization via Position Based Characterization Modlab UPenn 2014-07-24 | Cogging torque ripple minimization, also known as anticogging, is a software approach to making motors smoother. This video was presented at RSS 2014. More information can be found at http://modlabupenn.org/anticogging/.
Passive Stability of a Single Actuator MAV Modlab UPenn 2014-05-27 | As Micro Aerial Vehicles (MAVs) decrease in size, room for sensors, power, and actuators also decrease. One remedy is to decrease the number of required actuators. Flying vehicles with a single actuator are possible with the help of passive stability.
An Underactuated Propeller for Attitude Control in Micro Air Vehicles, IROS 2013 Modlab UPenn 2014-02-18 | For more information visit the Modlab website, a part of the GRASP Lab at the University of Pennsylvania. http://www.modlabupenn.org.This video accompanies the paper "An Underactuated Propeller for Attitude Control in Micro Air Vehicles" by James Paulos and Mark Yim at IROS 2013. The paper is available online through IEEE Xplore.
