waashk/dblp huggingface dataset:
a miniature mobile robot for navigation and positioning on the beating heart. robotic assistance enhances conventional endoscopy; yet, limitations have hindered its mainstream adoption for cardiac surgery. heartlander is a miniature mobile robot that addresses several of these limitations by providing precise and stable access over the surface of the beating heart in a less-invasive manner. the robot adheres to the heart and navigates to any desired target in a semiautonomous fashion. the initial therapies considered for heartlander generally require precise navigation to multiple surface targets for treatment. to balance speed and precision, we decompose any general target acquisition into navigation to the target region followed by fine positioning to each target. in closed-chest, beating-heart animal studies, we demonstrated navigation to targets located around the circumference of the heart, as well as acquisition of target patterns on the anterior and posterior surfaces with an average error of 1.7 mm. the average drift encountered during station-keeping was 0.7 mm. these preclinical results demonstrate the feasibility of precise semiautonomous delivery of therapy to the surface of the beating heart using heartlander.
extending collision avoidance methods to consider the vehicle shape, kinematics, and dynamics of a mobile robot. most collision avoidance methods do not consider the vehicle shape and its kinematic and dynamic constraints, assuming the robot to be point-like and omnidirectional with no acceleration constraints. the contribution of this paper is a methodology to consider the exact shape and kinematics, as well as the effects of dynamics in the collision avoidance layer, since the original avoidance method does not address them. this is achievable by abstracting the constraints from the avoidance methods in such a way that when the method is applied, the constraints already have been considered. this study is a starting point to extend the domain of applicability to a wide range of collision avoidance methods.
the flying brick: a cautionary note on testing flying robots using guide wires. a simple experiment demonstrates that an average vertical force can be produced by a small vibrator motor attached to a frame constrained to slide vertically on guide wires. the vertical force produced is sufficient to make the sliding element hover, similarly to a biologically inspired robotic insect. we show that this effect depends on the natural resonance frequency of the guide wires and the nature of the mechanical coupling between wires and sliding element. based on the result of this experiment, we recommend that a control experiment should be performed in order to reach unambiguous conclusions concerning the actual flying capabilities of robotic insects tested using this kind of methodology.
development of a flying robot with a pantograph-based variable wing mechanism. we develop a flying robot with a new pantographbased variable wing mechanism for horizontal-axis rotorcrafts (cyclogyro rotorcrafts). a key feature of the new mechanism is to have a unique trajectory of variable wings that not only change angles of attack but also expand and contract according to wing positions. as a first step, this paper focuses on demonstrating the possibility of the flying robot with this mechanism. after addressing the pantograph-based variable wing mechanism and its features, a simulation model of this mechanism is constructed. next, we present some comparison results (between the simulation model and experimental data) for a prototype body with the proposed pantograph-based variable wing mechanism. both simulation and experimental results show that the flying robot with this new mechanism can generate enough lift forces to keep itself in the air. furthermore, we construct a more precise simulation model by considering rotational motion of each wing. as a result of optimizing design parameters using the precise simulation model, flight performance experimental results demonstrate that the robot with the optimal design parameters can generate not only enough lift forces but a 155 gf payload as well.
the role of modular robotics in mediating nonverbal social exchanges. this paper outlines the use of modular robotics to encourage and facilitate nonverbal communication during therapeutic intervention in dementia care. a set of new socially interactive modular robotic devices called rolling pins (rps) has been designed and developed to assist the therapist in interacting with dementiaaffected patients. the rps are semitransparent plastic tubes that are capable of measuring their orientation and the speed of their rotation; at a local level, they have three types of feedback: red, green, and blue light, sound, and vibration. the peculiarity of the rps is that they are able to communicate with each other or with other devices equipped with the same radio communication technology. the rps are usually used in pairs, as the local feedback of an rp can be set depending not only on its own speed and orientation but also on the speed and the orientation of the peer rp. the system is not used as a therapeutic tool per se but as a facilitator and a mediator of social dynamics during normal therapy to counteract social isolation that can result in dementia through the loss of social skills. an experiment is reported that shows that by using the rps, the patients participated in the activity by coordinating their behavior with the therapist and imitating the same interaction patterns generated by the therapist.
nims-pl: a cable-driven robot with self-calibration capabilities. we present the networked infomechanical system for planar translation, which is a novel two-degree-of-freedom (2-dof) cable-driven robot with self-calibration and online drift-correction capabilities. this system is intended for actuated sensing applications in aquatic environments. the actuation redundancy resulting from in-plane translation driven by four cables results in an infinite set of tension distributions, thus requiring real-time computation of optimal tension distributions. to this end, we have implemented a highly efficient, iterative linear programming solver, which requires a very small number of iterations to converge to the optimal value. in addition, two novel self-calibration methods have been developed that leverage the robot's actuation redundancy. the first uses an incremental displacement, or jitter method, whereas the second uses variations in cable tensions to determine end-effector location. we also propose a novel least-squares drift-detection algorithm, which enables the robot to detect long-term drift. combined with self-calibration capabilities, this drift-monitoring algorithm enables long-term autonomous operation. to verify the performance of our algorithms, we have performed extensive experiments in simulation and on a real system.
visual servoing path planning via homogeneous forms and lmi optimizations. path planning is a useful technique for visual servoing as it allows one to take into account system constraints and achieve desired performances during the camera motion. in this paper, we propose a new framework for path planning based on the use of homogeneous forms and linear matrix inequalities (lmis). specifically, we introduce a general parametrization of the trajectories from the initial to the desired location based on homogeneous forms and a parameter-dependent version of the rodrigues formula. this allows us to impose typical constraints (field of view, workspace, joint, avoidance of collision, and occlusion) via positivity conditions on suitable homogeneous forms. then, we reformulate the problem of finding a trajectory in the 3-d space satisfying all these constraints as an lmi optimization that can handle the maximization of typical performances (e.g., visibility margin, similarity to a straight line). the planned camera path is tracked by using an image-based controller. the proposed approach is illustrated and validated through simulations and experiments.
control of a class of underactuated mechanical systems using sliding modes. in this paper, we present a sliding mode control algorithm to robustly stabilize a class of underactuated mechanical systems that are not linearly controllable and violate brockett's necessary condition for smooth asymptotic stabilization of the equilibrium, with parametric uncertainties. in defining the class of systems, a few simplifying assumptions are made on the structure of the dynamics; in particular, the damping forces are assumed to be linear in velocities. we first propose a switching surface design for this class of systems, and subsequently, a switched algorithm to reach this surface in finite time using conventional and higher order sliding mode controllers. the stability of the closed-loop system is investigated with an undefined relative degree of the sliding functions. the controller gains are designed such that the controller stabilizes the actual system with parametric uncertainty. the proposed control algorithm is applied to two benchmark problems: a mobile robot and an underactuated underwater vehicle. simulation results are presented to validate the proposed scheme.
construction methodology for a remote ultrasound diagnostic system. in the present paper, we describe a method for constructing a remote ultrasound diagnostic system. remote diagnosis can be realized using a communication network. we have developed a master-slave type remote medical system to diagnose shoulder diseases, such as dialysis-related amyloid arthropathy (draa), by ultrasonographic images. proper positioning" orientation, and contact force between the ultrasound probe and the affected area of the patient are required in order to acquire proper diagnostic images. safety and manipulability are also required when operating the remote medical system through a communication network. therefore, the system has impedance control cnpability for positioning of the master and slave manipulators in order to convey the contact force and enhance manipulability. in addition, the system has continuous-path control capability for the orientation of the slave manipulator in order to realize smooth and accurate motion of the ultrasound probe, even if the sampling rate of the transmission of the orientation data of the master manipulator is not sufficient. the results of remote diagnostic experiments demonstrated that a healthcare professional could diagnose real patients through a communication network using the constructed system.
power consumption modeling of skid-steer tracked mobile robots on rigid terrain. power consumption is a key element in outdoor mobile robot autonomy. this issue is very relevant in skid-steer tracked vehicles on account of their large ground contact area. in this paper, the power losses due to dynamic friction have been modeled from two different perspectives: 1) the power drawn by the rigid terrain and 2) the power supplied by the motors. comparison of both approaches has provided new insight on skid steering on hard flat terrains at walking speeds. experimental power models, which also include traction resistance and other power losses, have been obtained for two different track widths over marble flooring and asphalt with auriga-β, which is a full-size mobile robot. to this end, various internal probes have been set at different points of the power stream. furthermore, new energy implications for navigation of these kinds of vehicles have been deduced and tested.
a hybrid motion classification approach for emg-based human-robot interfaces using bayesian and neural networks. in a human-robot interface, the prediction of motion, which is based on context information of a task, has the potential to improve the robustness and reliability of motion classification to control prosthetic devices or human-assisting manipulators. this paper proposes a task model using a bayesian network (bn) for motion prediction. given information of the previous motion, this task model is able to predict occurrence probabilities of the motions concerned in the task. furthermore, a hybrid motion classification framework has been developed based on the bn motion prediction. besides the motion prediction, electromyogram (emg) signals are simultaneously classified by a probabilistic neural network (nn). then, the motion occurrence probabilities are combined with the nn classifier's outputs to generate motion commands for control. with the proposed motion classification framework, it is expected that classification performance can be enhanced so that motion commands can be more robust and reliable. experiments have been conducted with four subjects to demonstrate the feasibility of the proposed methods. in these experiments, forearm motions are classified with emg signals considering a cooking task. finally, robot manipulation experiments were carried. out to verify the proposed human interface system with a task of taking meal. the experimental results indicate that the proposed methods improved the robustness and stability of motion classification.
impairment-based 3-d robotic intervention improves upper extremity work area in chronic stroke: targeting abnormal joint torque coupling with progressive shoulder abduction loading. the implementation of a robotic system (act3d) that allowed for a quantitative measurement of abnormal joint torque coupling in chronic stroke survivors and, most importantly, a quantitative means of initiating and progressing an impairment-based intervention, is described. individuals with chronic moderate to severe stroke (n = 8) participated in this single-group pretest-posttest design study. subjects were trained over eight weeks by progressively increasing the level of shoulder abduction loading experienced by the participant during reaching repetitions as performance improved. reaching work area was evaluated pre- and postintervention for ten different shoulder abduction loading levels along with isometric single-joint strength and a qualitative clinical assessment of impairment. there was a significant effect of session (pre versus post) with an increase in reaching work area, despite no change in single-joint strength. this data suggests that specifically targeting the abnormal joint torque coupling impairment through progressive shoulder abduction loading is an effective strategy for improving reading work area following hemiparetic stroke. application of robotics, namely, the act3d allowed for quantitative control ofthe exercise parameters needed to directly target the synergistic coupling impairment. the targeted reduction of abnormal joint torque coupling is likely the key factor explaining the improvements in reaching range of motion achieved with this intervention.
intrinsic constraints of neural origin: assessment and application to rehabilitation robotics. ideally, robots used for motor rehabilitation, in particular, during assessment, should minimally perturb the voluntary movements of a subject. in this paper, we show how a state-of-theart back-drivable robot, i.e., a robot that can be moved by the user with a low perceived mechanical impedance, when used for assessment can still perturb the voluntary movements of a subject. in particular, we show that, despite its low mechanical impedance, a robot may still not comply with the intrinsic kinematic constraints, which are of neural origin and are adopted by the human brain to solve redundancy in motor tasks. specifically, the redundant task under consideration is the 2-d pointing task, which is performed by a subject with the sole use of the wrist [3 degree of freedom (dof) kinematics]. wrist orientations during pointing tasks are assessed in two different scenarios. in the first experiment, a lightweight handheld device is used, which introduces no loading effect. in the second experiment, similar pointing tasks are performed with the subject interacting with a state-of-the-art robot for wrist rehabilitation. in the first case, intrinsic kinematic constraints arise as 2-d surfaces embedded in the 3-d space of wrist configuration. such surfaces are typically subject-dependent and reveal personal motor strategies. in the second case, a strong influence of the robot is remarked. in particular, 2-d surfaces still arise but are similar for all subjects and are referable to a mechanical origin (excessive loading by the robot). the assessment approach described in this paper, including both the experimental apparatus and dataanalysis method, can be used as a test for the degree of backdrivability of mechanisms and robots in relation to constraints of neural origin, thus allowing the design of robots that can actually cope with such constraints. the clinical potential impact is also discussed.
a distributed heuristic for energy-efficient multirobot multiplace rendezvous. we consider the problem of finding a set of trajectories for a heterogeneous group of mobile robots, such that a single service robot can rendezvous with every other member of the team in a prescribed order, and the total travel cost is minimized. we present a simple heuristic controller that runs independently on each robot, yet is guaranteed to achieve an approximation to global solution in bounded time linear in population size. simulation experiments empirically show that the methocl finds approximated solutions of near-optimal quality on average.
partially flagged parallel manipulators: singularity charting and avoidance. there are only three 6-sps parallel manipulators with triangular base and platform, i.e., the octahedral, the flagged, and the partially flagged, which are studied in this paper. the forward kinematics of the octahedral manipulator is algebraically intricate, while those of the other two can be solved by three trilaterations. as an additional nice feature, the flagged manipulator is the only parallel platform for which a cell decomposition of its singularity locus has been derived. here, we prove that the partially flagged manipulator also admits a well-behaved decomposition, technically called a stratification, some of whose strata are not topological cells, however. remarkably, the adjacency diagram of the 5-d and 6-d strata (which shows what 5-d strata are contained in the closure of a 6-d one) is the same as for the flagged manipulator. the availability of such a decomposition permits devising a redundant 7-sps manipulator, combining two partially flagged ones, which admits a control strategy that completely avoids singularities. simulation results support these claims.
extending the limits of feature-based slam with b-splines. this paper describes a simultaneous localization and mapping (slam) algorithm for use in unstructured environments that is effective regardless of the geometric complexity of the environment. features are described using b-splines as modeling tool, and the set of control points defining their shape is used to form a complete and compact description of the environment, thus making it feasible to use an extended kalman-filter (ekf) based slam algorithm. this method is the first known ekf-slam implementation capable of describing general free-form features in a parametric manner. efficient strategies for computing the relevant jacobians, perform data association, initialization, and map enlargement are presented. the algorithms are evaluated for accuracy and consistency using computer simulations, and for effectiveness using experimental data gathered from different real environments.
qualitative vision-based path following. we present a simple approach for vision-based path following for a mobile robot. based upon a novel concept called the funnel lane, the coordinates of feature points during the replay phase are compared with those obtained during the teaching phase in order to determine the turning direction. increased robustness is achieved by coupling the feature coordinates with odometry information. the system requires a single off-the-shelf, forward-looking camera with no calibration (either external or internal, including lens distortion). implicit calibration of the system is needed only in the form of a single controller gain. the algorithm is qualitative in nature, requiring no map of the environment, no image jacobian, no homography, no fundamental matrix, and no assumption about a flat ground plane. experimental results demonstrate the capability of real-time autonomous navigation in both indoor and outdoor environments and on flat, slanted, and rough terrain with dynamic occluding objects for distances of hundreds of meters. we also demonstrate that the same approach works with wide-angle and omnidirectional cameras with only slight modification.
vibration-induced frequency-controllable bidirectional locomotion for assembly and microrobotic applications. this paper describes vibration-induced bidirectional locomotion of a milliscale cylindrical body. using a laterally vibrating platform, we achieved a frequency-controlled bidirectional movement by attaching two polydimethylsiloxane cylindrical rods with microscale ratchet-shaped legs of different densities facing in opposite directions. the polymeric body (2 × 2 × 20 mm3) was placed on a glass slide covered by thin lubricating oil and vibrated at a constant amplitude of 0.2 mm. the micromobile composite cylinder changed its direction of motion at a cross-over frequency of 156 hz. the cross-over phenomena is due to the difference between static and kinetic friction coefficients of the two opposing parts.
a synchronization approach to trajectory tracking of multiple mobile robots while maintaining time-varying formations. in this paper, we present a synchronization approach to trajectory tracking of multiple mobile robots while maintaining time-varying formations. the main idea is to control each robot to track its desired trajectory while synchronizing its motion with those of other robots to keep relative kinematics relationships, as required by the formation. first, we pose the formation-control problem as a synchronization control problem and identify the synchronization control goal according to the formation requirement. the formation error is measured by the position synchronization error, which is defined based on the established robot network. second, we develop a synchronous controller for each robot's translation to guarantee that both position and synchronization errors approach zero asymptotically. the rotary controller is also designed to ensure that the robot is always oriented toward its desired position. both translational and rotary controls are supported by a centralized high-level planer for task monitoring and robot global localization. finally, we perform simulations and experiments to demonstrate the effectiveness of the proposed synchronization control approach in the formation control tasks.
dynamic manipulability of multifingered grasping. in this paper, we extend the concept of dynamic manipulability to evaluate the dynamic property of multifingered grasping systems consisting of amultifingered hand and a grasped object, and propose a measure of dynamic manipulability of multifingered grasping. similar to the original dynamic manipulability, the proposed measure evaluates the mapping from a set of realizable joint torques to a set of resultant accelerations of the grasped object, which forms an ellipsoid under a constant internal force constraint. it is clearly shown that the internal forces not only affect the volume of the ellipsoid, but also the amount of offset of the ellipsoid, while the gravity forces simply induce an offset. a new measure, i.e., omnidirectionality, is introduced to add a penalty to the original manipulability measure, which simply evaluates the volume of the ellipsoid, depending on how much the ellipsoid is offset. numerical examples by using a simple two-fingered robot hand are shown to demonstrate the effectiveness of the proposed measure.