The use of unmanned aerial systems for industrial applications has evolved considerably in recent years. This paper presents an aerial system capable of perching autonomously on pipes for inspection and maintenance in industrial environments. The target pipe to perch on is detected using a visual algorithm based on a semantic convolutional neuronal network. The information from a color camera is used to segment the image. Then, the segmentation information is fused with a depth image to estimate the pipe's pose, so that the pose of the robot can be controlled relative to it. The aerial robot is equipped with a soft landing system that robustly attaches it to the pipe. The article presents the complete development of the system. Experimental results performed in outdoor environments are shown.

The use of aerial systems in a variety of real applications is increasing nowadays. These offer solutions to existing problems in ways that have never seen before thanks to their capability to perform perching, grasping or manipulating in inaccessible or dangerous places. Many of these applications require small-sized robots that can maneuver in narrow environments. However, these are required to have also strength enough to perform the desired tasks. This balance is sometimes unreachable due to the fact that traditional servomotors are too heavyweight for being carried by such small unmanned aerial systems (UAS). This paper, offers a innovative solution based on twisted and coiled polymers (TCP) muscles. These tensors have a high weight/strength ratio (up to 200 times) compared with traditional servos. In this work, the practical and modeling work done by the authors is presented. Then, a preliminary design of a bio-inspired claw for an unmanned aerial system (UAS) is shown. This claw has been developed using additive manufacturing techniques with different materials. Actuated with TCP, it is intrinsically compliant and offers a great force/weight ratio.

Taking inspiration from nature, the work presented in this paper aims to develop bio-inspired claws to be used for grasping and perching in flapping-wing aerial systems. These claws can be 3D printed out of two different materials and will be capable of adapt to any shape. Also, they will be soft for avoiding undesired damages on the objects when performing manipulation. These claws will be actuated by shape memory alloys (SMA) springs to get rid of the weight of traditional servos. The design of all the components will be explained in this work. Also, the challenges of being able to control SMA using only a LiPo battery on an aerial vehicle will be exposed. The solutions applied and electronics used will be also described. Lastly, experiments made both in test bench as on flight will be summarized.

Trying to optimize the design of aerial robotics systems, this work presents an optimized low-weight landing system for flapping-wing aerial robots. The design, based on the use of low-sized neodymium magnets, intends to provide that these aerial robots have the capability of landing in restricted areas by using the presented solution. This capacity will increase the application range of these robots. A study of this situation has been done to analyze the perching maneuver forces and evaluate the system. The solution presented is low-weight, lowsized, and also relatively inexpensive. Therefore, this solution may apply to most ornithopter robots. Design, analysis of the implied forces, development and experimental validation of the idea are presented in this work, demonstrating that the developed solution can overcome the ornithopter's payload limitation providing an efficient and reliable solution.

Variable-pitch propellers quadrotors possess nonlinear algebraic relations between force/moment of the system and thrust factors of the rotor dynamics. The nonlinear relations make the thrust allocation a challenging topic in overall control design. The state-dependent Riccati equation (SDRE) is selected as a controller for regulation task in fully coupled six degree-of-freedom (DoF) mode. Common designs of the SDRE fail to deliver a fully coupled six-DoF control due to under-actuation. Virtual constraints are used to deliver a position and orientation control in a cascade design. Within the structure of the SDRE, four thrust allocation methods are proposed to compute the thrust factors based on the output results of control system. Practical implementation has been the main reason to generate such allocations. The use of Mean Value Theorem makes it possible to find an implementable formalism for thrust factors since they can be categorized as non-affine systems. Agile and aggressive maneuver is one of the application of the variable-pitch propellers quadrotors; so, flip maneuver is studied to highlight the advantages of the thrust allocation methods. Analysis of the four methods and comparisons are carried out to present the advantages and disadvantages of the proposed structures.