Abstract :Recently we witnessed an increasing trend for autonomous aerial vehicles in the city’s sky to deliver goods, transport passengers, attend medical support and more. These vehicles perform high mobility for point-to-point missions, but to do so, they should cruise across the sky with minimum interference. As these trends grow, more vehicles will demand these safe routes as more potential collisions require resolution.
Here we give some insights to a preliminary novel concept of a low-altitude air transport system (LAAT) that supplies the infrastructure for the aerial vehicles to move in the urban area. Inspired by the well-researched ground transportation methods, the suggested LAAT system is based on the natural relation between density and accumulation of the vehicles in a given area – as described in the macroscopic fundamental diagram (MFD), and then using a flow control method called perimeter control to regulate the inter-regional flow from adjacent regions.
A micro-simulation of a LAAT vehicle was designed, including mission definition and collision avoidance mechanism, and then it was implemented in an aggregated simulation to show that an MFD-like relation exists in a given region of LAAT system similarly to ground traffic MFD. Then, an adaptive perimeter controller is designed and tested in several multi-regional simulations. The controller performance was measured in the meaning of network congestion avoidance in different scenarios, including different number of connected regions, different regional and inter-regional flow demand (attraction) and tested on the plant model – either original non-linear model or simplified partially-linearized model.
The simulations show that the aerial vehicles flow indeed perform a MFD relation, and the extracted MFD was used to design a perimeter controller. The simulations show that the controller successfully prevents congestion on the partially-linearized model of the multi-regional scenarios and extends the stability of the system to harsh demand in the original non-linear model of the multi-regional scenarios.
Afterwards, robustness research was performed on the designed perimeter controller to evaluate the dependency of the solutions improvement on several key parameters under expected real-life implementation difficulties such as controller-plant channel delay and control communication constraints.
Ronen Brafman – Ben-Gurion University
When: 08.06.2022 at 15:00
Abstract: While one-trick robots are abundant in industry, constructing an autonomous robot that can perform multiple tasks flexibly, such as a service robot, is a difficult task, we are yet to reach. A large number of robotics researchers have been working hard to design and implement algorithms for diverse robotic skills. But these skills are hard to put together: A lot of software engineering and thought goes into each script that operates them. In this talk I will present a research program seeking to change this situation, providing plug’s play autonomy for robotic via what we call the autonomous operating system (AOS).
This system uses a language we designed for documenting robotic skill code to provide the AOS with the information needed to decide when and how tol execute each skill.
No additional software-engineering effort is required beyond this specification.
I will describe our initial version of this system and our future plans.
The talk is non-technical and requires little background.
You can see the seminar here
When: Wednesday, April 27th at 15:00
Abstract: In this talk, I first discuss how we leverage machine learning methods to generate cooperative policies for multi-robot systems. I describe how we use Graph Neural Networks (GNNs) to learn effective communication strategies for decentralized coordination. I then show how our GNN-based policy is able to achieve near-optimal performance across a variety of problems, at a fraction of the real-time computational cost. Finally, I present some pioneering real-robot experiments that demonstrate the transfer of our methods to the physical world.
When: Wednesday, April 13th at 15:00
Talk Abstract The questions of dexterity, agility, and learning from a few demonstrations have intrigued robotics researchers. In this talk, I will explore answers and solutions to these questions via the following case studies: (i) a dexterous manipulation system capable of re-orienting novel objects. (ii) a quadruped robot that is substantially more agile than its counterparts (runs, spins) on challenging natural terrains. (iii) framework for learning task-sensitive perceptual representations for planning and out-of-distribution generalization. While a lot of recent progress in robotics is driven by perception, we show that learned controllers can help address problems that were previously thought to be hard. I will discuss our findings, the insights we gained, and the road ahead.
When: Wednesday, April 6th at 15:00
Abstract: Classic state estimation tools (e.g., determining position/velocity of a robot from noisy sensor data) have been in use since the 1960s, perhaps the most famous technique being the Kalman filter. For difficult-to-model nonlinear systems with rich sensing (e.g., almost any real-world robot), clever adaptations are needed to the classic tools. In this talk, I will first briefly summarize an idea that has become standard practice in our group over the last several years: continuous-time trajectory estimation (and its connection to sparse Gaussian process regression). I will then discuss two new frameworks we have been pursuing lately: exactly sparse Gaussian variationally inference (ESGVI) and Koopman state estimation (KoopSE). ESGVI seeks to minimize the Kullback-Leibler divergence between a Gaussian state estimate and the full Bayesian posterior; however, the framework also easily allows for parameter learning through Expectation Maximization and we’ve used this to learn simple parameters such as constant system matrices and covariances, but also to model rich sensors using Deep Neural Networks and learn the weights from data. KoopSE takes a different approach by lifting a nonlinear system into a high-dimensional Reproducing Kernel Hilbert Space where we can treat it as linear and apply classic estimation tools; it also allows for the system to be learned from training data quite efficiently. I will give simple intuitive explanations of the mathematics and show some examples of things working in practice.
Work towards PhD degree under the supervision of Prof. Amir Degani
When: 14.4.2022 at 11:00
The seminar will be held in hybrid format: Water institute auditorium
Abstract: In recent years, there has been considerable advancement in the fields of planning and control of legged robots, but legged robots are still extremely limited. Most research effort has been directed toward bipedal walking and quadrupedal walking and running, and not so much at bipedal running. Dynamic-legged locomotion is difficult to plan and execute, it requires robust control strategies and fast planning algorithms. In this work, we describe a strategy for traversing uneven complex terrain without the need to perform explicit foot placement. This will be achieved using a funnel library approach in combination with an online receding horizon planner. Thus, enabling the robot to take full advantage of its dynamics and the potential reaction forces presented by the environment. We demonstrate, in simulation, multiple scenarios, from traversing a low-friction obstacle, all the way to inclined surfaces and chute climbing with intermittent low-friction patches. We present an efficient approach for generating transitions from running to climbing without the need for a long planning horizon. We investigate the SLIP, ASLIP, and the actuated SLIP models and several in-stride control approaches.
When: 23.3.2022 at 15:00
Abstract: In 2016, Schlumberger started to deploy automated drilling, using plan-based control, across multiple rigs in several basins. Five years later, the technology has drilled more than half-a-million feet under fully autonomous control, with an estimated 17% efficiency improvement over human operations. A significant challenge in this deployment has been the range of rigs on which the system has been deployed, each with different degrees of access to control systems, different sensors and all of them in different geophysical settings. In this talk I will outline the planning technology and the benefits it has brought in the achievement of this success, the approaches we have adopted to interfacing between planning and execution, the scope of some of the other uses we have found for the same approach and, depending on time, some of the planning-related problems we are currently investigating.