Most of the signal processing that we will study in this course involves local operations on a signal, namely transforming the signal by applying linear combinations of values in the neighborhood of each sample point. You are familiar with such operations from Calculus, namely, taking derivatives and you are also familiar with this from optics namely blurring a signal. We will be looking at sampled signals only. Let's start with a few basic examples. Local difference Suppose we have a 1D image and we take the local difference of intensities, DI(x) = 1 2 (I(x + 1) − I(x − 1)) which give a discrete approximation to a partial derivative. (We compute this for each x in the image.) What is the effect of such a transformation? One key idea is that such a derivative would be useful for marking positions where the intensity changes. Such a change is called an edge. It is important to detect edges in images because they often mark locations at which object properties change. These can include changes in illumination along a surface due to a shadow boundary, or a material (pigment) change, or a change in depth as when one object ends and another begins. The computational problem of finding intensity edges in images is called edge detection. We could look for positions at which DI(x) has a large negative or positive value. Large positive values indicate an edge that goes from low to high intensity, and large negative values indicate an edge that goes from high to low intensity. Example Suppose the image consists of a single (slightly sloped) edge:

http://ieeexplore.ieee.org/iel5/5/31307/01456462.pdf

Linear systems

Bilateral teleoperation: An historical survey

Summary) The abstract should follow the structure of the article (relevance, degree of exploration of the problem, the goal, the main results, conclusion) and characterize the theoretical and practical significance of the study results. The abstract should not contain wording echoing the title, cumbersome grammatical structures and abbreviations. The text should be written in scientific style. The volume of abstracts (summaries) depends on the content of the article, but should not be less than 250 words. All abbreviations must be disclosed in the summary (in spite of the fact that they will be disclosed in the main text of the article), references to the numbers of publications from reference list should not be made. The sentences of the abstract should constitute an integral text, which can be made by use of the words “consequently”, “for example”, “as a result”. Avoid the use of unnecessary introductory phrases (eg, “the author of the article considers...”, “The article presents...” and so on.)

/pdf/ministry-of-education-and-science-of-the-russian-federation-7m2jn0xnm1.pdf

Ministry of Education and Science of the Russian Federation

One of the most important design problems for multi-UAV (Unmanned Air Vehicle) systems is the communication which is crucial for cooperation and collaboration between the UAVs. If all UAVs are directly connected to an infrastructure, such as a ground base or a satellite, the communication between UAVs can be realized through the in-frastructure. However, this infrastructure based communication architecture restricts the capabilities of the multi-UAV systems. Ad-hoc networking between UAVs can solve the problems arising from a fully infrastructure based UAV networks. In this paper, Flying Ad-Hoc Networks (FANETs) are surveyed which is an ad hoc network connecting the UAVs. The differences between FANETs, MANETs (Mobile Ad-hoc Networks) and VANETs (Vehicle Ad-Hoc Networks) are clarified first, and then the main FANET design challenges are introduced. Along with the existing FANET protocols, open research issues are also discussed.

Flying Ad-Hoc Networks (FANETs)

Aircraft wings are a compromise that allows the aircraft to fly at a range of flight conditions, but the performance at each condition is sub-optimal. The ability of a wing surface to change its geometry during flight has interested researchers and designers over the years as this reduces the design compromises required. Morphing is the short form for metamorphose; however, there is neither an exact definition nor an agreement between the researchers about the type or the extent of the geometrical changes necessary to qualify an aircraft for the title ‘shape morphing.’ Geometrical parameters that can be affected by morphing solutions can be categorized into: planform alteration (span, sweep, and chord), out-of-plane transformation (twist, dihedral/gull, and span-wise bending), and airfoil adjustment (camber and thickness). Changing the wing shape or geometry is not new. Historically, morphing solutions always led to penalties in terms of cost, complexity, or weight, although in certain circumstances, thes...

A Review of Morphing Aircraft

Uncrewed aircraft system (UAS) observations collected during the 2018 Lower Atmospheric Process Studies at Elevation—a Remotely Piloted Aircraft Team Experiment (LAPSE-RATE) field campaign were assimilated into a high-resolution configuration of the Weather Research and Forecasting Model using an ensemble Kalman filter. The benefit of UAS observations was assessed for a terrain-driven (drainage and upvalley) flow event that occurred within Colorado’s San Luis Valley (SLV) using independent observations. The analysis and prediction of the strength, depth, and horizontal extent of drainage flow from the Saguache Canyon and the subsequent transition to upvalley and up-canyon flow were improved relative to that obtained both without data assimilation (benchmark) and when only surface observations were assimilated. Assimilation of UAS observations greatly improved the analyses of vertical variations in temperature, relative humidity, and winds at multiple locations in the northern portion of the SLV, with reductions in both bias and the root-mean-square error of roughly 40% for each variable relative to the benchmark run. Despite these noted improvements, some biases remain that were tied to measurement error and/or the impact of the boundary layer parameterization on vertically spreading the observations, both of which require further exploration. The results presented here highlight how observations obtained with a fleet of profiling UAS improve limited-area, high-resolution analyses and short-term forecasts in complex terrain.

Assimilation of a Coordinated Fleet of Uncrewed Aircraft System Observations in Complex Terrain: EnKF System Design and Preliminary Assessment

Micro aerial vehicles (MAVs) are distinguished by their small size, low aspect ratio, and low velocity. As a result, MAVs fly at low Reynolds number flow regimes with significant drag characteristics and strong tip vortices. This investigation is focused on the aerodynamic characteristics of a recently developed MAV at the University of Colorado. The Colorado MAV has a flexible membrane wing with an aspect ratio of 1.2 and a chord of 0.27 m. Numerical simulations of the flow around the Colorado fixed wing MAV are presented using a steady state parallel compressible Navier-Stokes solver. The computational grid has 510,000 nodes and about 3 million tetrahedral elements. The maximum calculated lift coefficient is approximately 1.2. The airplane stall angle is at 30°. The high stall angle is attributed to the enhanced lift from a low pressure region above the wing caused by strong tip vortices. Minimum drag coefficient was calculated to be 0.06 at 2° angle of attack. A laminar separation bubble is formed on the upper surface of the wing at moderate angle of attack. The drag increases rapidly as the angle of attack increases. A maximum aerodynamic efficiency of L/D = 4 is observed when flying at 10 m/s.

Numerical Simulation of Flow Around the Colorado Micro Aerial Vehicle

Tracking Dynamic Star Curves Using Guidance Vector Fields

This paper describes a novel motor and encoder concept that is designed to reduce cost. The new design uses a low-cost stepper motor and a low-resolution optical encoder, together with high speed digital signal processing to achieve high torque levels with low ripple, as well as accurate position and velocity sensing. While more involved electronics and signal processing are required, the cost of these components continue to decrease compared to that of motors and sensors, making the overall proposed design feasible and economical. Data from a prototype implementation demonstrate the promise of this design.

Low cost actuator and sensor for high-fidelity haptic interfaces

This paper describes a novel bow spring and tendon actuator design for a haptic interface that provides high-bandwidth force transmission to the fingers, with a large range of motion. This is combined with a low-cost stepper motor and a low-cost optical encoder, along with self-calibration and control compensation to produce a smooth force source with excellent hard virtual wall rendering capabilities. Four techniques are discussed to compensate for bow spring, friction, and ripple torques in the actuator. Experimental results quantify the achieved force rendering quality of each technique, and provide a measure of hard virtual surface rendering quality in one degree of freedom.

Dale Lawrence

Papers

Assimilation of a Coordinated Fleet of Uncrewed Aircraft System Observations in Complex Terrain: EnKF System Design and Preliminary Assessment

Numerical Simulation of Flow Around the Colorado Micro Aerial Vehicle

Tracking Dynamic Star Curves Using Guidance Vector Fields

Low cost actuator and sensor for high-fidelity haptic interfaces

Bow spring/tendon actuation for low cost haptic interfaces