David Saldaña

University of Pennsylvania | UP · GRASP Laboratory

Rural communities in remote areas often encounter significant challenges when it comes to accessing emergency healthcare services and essential supplies due to a lack of adequate transportation infrastructure. The situation is further exacerbated by poorly maintained, damaged, or flooded roads, making it arduous for rural residents to obtain the ne...

We present an aerial vehicle composed of a custom quadrotor with tilted rotors and a helium balloon, called SBlimp. We propose a novel control strategy that takes advantage of the natural stable attitude of the blimp to control translational motion. Different from cascade controllers in the literature that controls attitude to achieve desired trans...

We present an aerial vehicle composed of a custom quadrotor with tilted rotors and a helium balloon, called SBlimp. We propose a novel control strategy that takes advantage of the natural stable attitude of the blimp to control translational motion. Different from cascade controllers in the literature that controls attitude to achieve desired trans...

Aerial operation in turbulent environments is a challenging problem due to the chaotic behavior of the flow. This problem is made even more complex when a team of aerial robots is trying to achieve coordinated motion in turbulent wind conditions. In this paper, we present a novel multi-robot controller to navigate in turbulent flows, decoupling the...

The use of cables for aerial manipulation has shown to be a lightweight and versatile way to interact with objects. However, fastening objects using cables is still a challenge and human is required. In this work, we propose a novel way to secure objects using hitches. The hitch can be formed and morphed in midair using a team of aerial robots with...

Traditional aerial vehicles have limitations in their capabilities due to actuator constraints, such as motor saturation. The hardware components and their arrangement are designed to satisfy specific requirements and are difficult to modify during operation. To address this problem, we introduce a versatile modular multi-rotor vehicle that can cha...

Dexterous manipulation of objects through fine control of physical contacts is essential for many important tasks of daily living. A fundamental ability underlying fine contact control is compliant control, \textit{i.e.}, controlling the contact forces while moving. For robots, the most widely explored approaches heavily depend on models of manipul...

Coordination in a large number of networked robots is a challenging task, especially when robots are constantly moving around the environment and there are malicious attacks within the network. Various approaches in the literature exist for detecting malicious robots, such as message sampling or suspicious behavior analysis. However, these approach...

The use of cables for aerial manipulation has shown to be a lightweight and versatile way to interact with objects. However, fastening objects using cables is still a challenge and human is required. In this work, we propose a novel way to secure objects using hitches. The hitch can be formed and morphed in midair using a team of aerial robots with...

Dexterous manipulation of objects through fine control of physical contacts is essential for many important tasks of daily living. A fundamental ability underlying fine contact control is compliant control, i.e., controlling the contact forces while moving. For robots, the most widely explored approaches heavily depend on models of manipulated obje...

Traditional aerial vehicles have limitations in their capabilities due to actuator constraints, such as motor saturation. The hardware components and their arrangement are designed to satisfy specific requirements and are difficult to modify during operation. To address this problem, we introduce a versatile modular multi-rotor vehicle that can cha...

From ancient times, humans have been using cables and ropes to tie, carry, and manipulate objects by folding knots. However, automating knot folding is challenging because it requires dexterity to move a cable over and under itself. In this paper, we propose a method to fold knots in midair using a team of aerial vehicles. We take advantage of the...

We introduce an open-source quadrotor platform called Customizable-ModQuad, an aerial vehicle design that is modular, low-cost, lightweight, easy to manufacture and maintain , and highly customizable. The main frame of this design is composed of carbon-fiber rods and 3D-printed connection parts, which embraces the involvement of fast-prototyping. W...

We introduce an open-source quadrotor platform called Customizable-ModQuad, an aerial vehicle design that is modular, low-cost, lightweight, easy to manufacture and maintain , and highly customizable. The main frame of this design is composed of carbon-fiber rods and 3D-printed connection parts, which embraces the involvement of fast-prototyping. W...

From ancient times, humans have been using cables and ropes to tie, carry, and manipulate objects by folding knots. However, automating knot folding is challenging because it requires dexterity to move a cable over and under itself. In this paper, we propose a method to fold knots in midair using a team of aerial vehicles. We take advantage of the...

We present a design, model, and control for a novel jumping-flying robot that is called PogoDrone. The robot is composed of a quadrotor with a passive mechanism for jumping. The robot can continuously jump in place or fly like a normal quadrotor. Jumping in place allows the robot to quickly move and operate very close to the ground. For instance, i...

Traditional aerial vehicles have specific characteristics to perform specific tasks. For instance, in aerial transportation , the vehicles are limited with a maximum payload that cannot be extended to transport heavier objects. We propose a versatile modular robotic system that can increase its payload and controllable degrees of freedom by reconfi...

Transporting objects using quadrotors with cables has been widely studied in the literature. However, most of those approaches assume that the cables are previously attached to the load by human intervention. In tasks where multiple objects need to be moved, the efficiency of the robotic system is constrained by the requirement of manual labor. Our...

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 oth...

Transporting objects using quadrotors with cables has been widely studied in the literature. However, most of those approaches assume that the cables are previously attached to the load by human intervention. In tasks where multiple objects need to be moved, the efficiency of the robotic system is constrained by the requirement of manual labor. Our...

In this article, we propose an approach to construct a time-varying communication topology with a resilient consensus performance for robot swarms with limited communication ranges. The robots are deployed to explore a large task space and achieve consensus despite the existence of a finite number of noncooperative members in the team. Existing met...

Traditional aerial vehicles are usually custom-designed for specific tasks. Although they offer an efficient solution, they are not always able to adapt to changes in the task specification, e.g., increasing the payload. This applies to quadrotors, having a maximum payload and only four controllable degrees of freedom, limiting their adaptability t...

Self-reconfiguration algorithms in the literature rely on high-accuracy global positioning systems which are not realistic for real-world applications. In this paper, we study self-reconfiguration algorithms using a combination of low-accuracy global positioning systems (e.g., GPS) and on-board relative positioning (e.g. visual sensing) for precise...

Transporting objects using aerial robots has been widely studied in the literature. Still, those approaches always assume that the connection between the quadrotor and the load is made in a previous stage. However, that previous stage usually requires human intervention, and autonomous procedures to locate and attach the object are not considered....

This paper presents a resilient mechanism to allocate heterogeneous robots to tasks under difficult environmental conditions such as weather events or adversarial attacks. Our primary objective is to ensure that each task is assigned the requisite level of resources, measured as the aggregated capabilities of the robots allocated to the task. By ke...

In this paper, we consider environmental boundaries that can be represented by a time-varying closed curve. We use n robots equipped with location sensors to sample the dynamic boundary. The main difficulty during the prediction process is that only n boundary points can be observed at each time step. Our approach combines finite Fourier series for...

For a multi-robot system equipped with heterogeneous capabilities, this paper presents a mechanism to allocate robots to tasks in a resilient manner when anomalous environmental conditions such as weather events or adversarial attacks affect the performance of robots within the tasks. Our primary objective is to ensure that each task is assigned th...

In this paper, we consider environmental boundaries that can be represented by a time-varying closed curve. We use n robots equipped with location sensors to sample the dynamic boundary. The main difficulty during the prediction process is that only n boundary points can be observed at each time step. Our approach combines finite Fourier series for...

We consider a team of mobile robots with limited communication range tasked to coordinate in large environments. The robots need to maximize the covered area and achieve consensus in the presence of non-cooperative robots. Existing works in robot networks showed that a team can achieve resilient consensus by maintaining an r-robust communication ne...

We present a self-reconfiguration technique by which a modular flying platform can mitigate the impact of rotor failures. In this technique, the system adapts its configuration in response to rotor failures to be able to continue its mission while efficiently utilizing resources. A mixed integer linear program determines an optimal module-to-positi...

Robotic modular systems have the ability to create and break physical links to self-assemble larger custom robots for general tasks. In case of changes in the task or the environment, they can dynamically self-adapt by self-reconfigure during the mission. However, applying those concepts to flying vehicles is still a challenge. In this paper, we pr...

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 intro...

This paper presents guarantees to satisfy resilience on the communication network of robot formations. In these resilient networks, cooperative robots can achieve consensus in the presence of faulty or malicious robots. We propose a design framework on triangular and square lattices, providing an underlying structure for proximity-based robot netwo...

Achieving consensus in distributed robot networks is a challenging task when the network contains non-cooperative robots. The conditions of robustness in communication networks are very restrictive and difficult to adapt to robot networks where the communication links are based on proximity. In this paper, we present a new topology network that is...

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 match...

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...

Consensus algorithms allow multiple robots to achieve agreement on estimates of variables in a distributed manner, hereby coordinating the robots as a team, and enabling applications such as formation control and cooperative area coverage. These algorithms achieve agreement by relying only on local, nearest-neighbor communication. The problem with...

Environmental boundaries, such as the borderline of a forest fire or an oil spill, pose a significant threat for living organisms. Anticipating the dynamics of these phenomena is a potentially life-saving indicator to support efficient and effective evacuations or to dispel the hazard. We propose a decentralized coordination method that allows mult...

In this work, multiple robots circulate around the boundary of a desired region in order to create a virtual fence. The aim of the this fence is to avoid internal or external agents crossing through the delimited area. In this paper, we propose a distributed technique that allows a team of robots to plan the deformation of the boundary shape in ord...

We consider networks of dynamic agents that execute cooperative, distributed control algorithms in order to coordinate themselves and to collectively achieve goals. The agents rely on consensus algorithms that are based on local interactions with their nearest neighbors in the communication graph. However, such systems are not robust to one or more...

We present a method that enables resilient formation control for mobile robot teams in the presence of non-cooperative (defective or malicious) robots. Recent results in network science define graph topological properties that guarantee resilience against faults and attacks on individual nodes in static networks. We build on these results to propos...

Consensus algorithms allow multiple robots to achieve agreement on estimates of variables in a distributed manner, hereby coordinating the robots as a team, and enabling applications such as formation control and cooperative area coverage. These algorithms achieve agreement by relying only on local, nearest-neighbor communication. The problem with...

Predicting the behavior of dangerous environmental boundaries, like spreading fire or oil spill, provides relevant information to mitigate the problem or even to support evacuation actions in order to save human or animal lives. In this letter, we present a model that uses a single robot moving around an environmental boundary in order to predict i...

Searching for regions in abnormal conditions is a priority in environments susceptible to catastrophes (e.g. forest fires or oil spills). Those disasters usually begin with an small anomaly that may became unsustainable if it is not detected at an early stage. We propose a probabilistic technique to coordinate multiple robots in perimeter searching...

This paper describes the strategy of Y-Rescue team to the RoboCup Rescue 2015 Agent & Multi-agent challenge competition. For the agent competition, our approach relies on field agents capable of individual decision making, relegating the center agents to an informa-tional role. Our main contributions are the scheme for prediction of fire evolution...

In many cases, large area disasters could be possibly be prevented if the incipient small-scale anomalies are detected in their early stages. A way to accomplish this would be to have multiple sensors deployed in disaster prone areas to detect anomalies. However, compared to static sensor networks, robotic sensor networks offer advantages such as a...

This paper describes a probabilistic technique to coordinate multiple robots in perimeter searching and tracking tasks, which are typical when they have to detect, and follow anomalies in an environment (e.g. Fire in a forest). The proposed method is based on particle filter technique, it uses multiple robots to fuse distributed sensor information...

Nowadays there are a variety of algorithms for robotic sensors that attack the problem of tracking perimeters of anomalies in physical environments. Such anomalies can be seen in applications such as forest fire detection or tracking temperature gradients in the sea. In this paper we propose an improved algorithm for anomalies perimeter tracking, w...

Robotic sensor networks are used to monitor physical environments that require measurement of physical variables in real time to prevent disaster by detecting and locating anomalies. In this paper we propose a model based on intelligent agents to control a robotic sensor network that detects and traks the perimeter of anomalies in a physical enviro...