The advent of rotor-based hopping robots has created very capable hopping platforms with high agility and efficiency, and similar controllability, as compared to their purely flying quadrotor counterparts. Advances in robot performance have increased the hopping height to greater than 4 meters and opened up the possibility for more complex aerial trajectories (i.e., behaviors). However, currently hopping robots do not directly control their aerial trajectory or transition to flight, eliminating the efficiency benefits of a hopping system. Here we show a real-time, computationally efficiency, non-linear drag compensated, trajectory generation methodology and accompanying Lyapunov-based controller. The combined system can create and follow complex aerial trajectories from liftoff to touchdown on horizontal and vertical surfaces, while maintaining strick control over the orientation at touchdown. The computational efficiency provides broad applicability across all size scales of hopping robots while maintaining applicability to quadrotors in general.

--This paper presents the design of a pose estimator for a four wheel independent steer four wheel independent drive (4WIS4WID) wall climbing mobile robot, based on the fusion of multimodal measurements, including wheel odometry, visual odometry, and an inertial measurement unit (IMU) data using Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF). The pose estimator is a critical component of wall climbing mobile robots, as their operational environment involves carrying precise measurement equipment and maintenance tools in construction, requiring information about pose on the building at the time of measurement. Due to the complex geometry and material properties of building fac ades, the use of traditional localization sensors such as laser, ultrasonic, or radar is often infeasible for wall-climbing robots. Moreover, GPS-based localization is generally unreliable in these environments because of signal degradation caused by reinforced concrete and electromagnetic interference. Consequently, robot odometry remains the primary source of velocity and position information, despite being susceptible to drift caused by both systematic and non-systematic errors. The calibrations of the robot's systematic parameters were conducted using nonlinear optimization and Levenberg-Marquardt methods as Newton-Gauss and gradient-based model fitting methods, while Genetic algorithm and Particle swarm were used as stochastic based methods for kinematic parameter calibration. Performance and results of the calibration methods and pose estimators were validated in detail with experiments on the experimental mobile wall climbing robot.

Breakthroughs, discoveries, and DIY tips sent every weekday. Gravity seems like a predictable, even mundane, aspect of existence. The physics dictating one of the universe's four fundamental forces is relatively straightforward to understand and calculate (most of the time, at least). Even so, the relationships between objects with mass and energy continues to surprise physical engineers. Take recent observations made by a team at the University of Waterloo, for example.

As aerial robots gain traction in industrial applications, there is growing interest in enhancing their physical interaction capabilities. Pushing tasks performed by aerial manipulators have been successfully demonstrated in contact-based inspections. However, more complex industrial applications require these systems to support higher-DoF (Degree of Freedom) manipulators and generate larger forces while pushing (e.g., drilling, grinding). This paper builds on our previous work, where we introduced an aerial vehicle with a dynamically displacing CoM (Center of Mass) to improve force exertion during interactions. We propose a novel approach to further enhance this system's force generation by optimizing its CoM location during interactions. Additionally, we study the case of this aerial vehicle equipped with a 2-DoF manipulation arm to extend the system's functionality in tool-based tasks. The effectiveness of the proposed methods is validated through simulations, demonstrating the potential of this system for advanced aerial manipulation in practical settings.

Aerial unperching of multirotors has received little attention as opposed to perching that has been investigated to elongate operation time. This study presents a new aerial robot capable of both perching and unperching autonomously on/from a ferromagnetic surface during flight, and a switching controller to avoid rotor saturation and mitigate overshoot during transition between free-flight and perching. To enable stable perching and unperching maneuvers on/from a vertical surface, a lightweight ($\approx$ $1$ \si{kg}), fully actuated tiltrotor that can hover at $90^\circ$ pitch angle is first developed. We design a perching/unperching module composed of a single servomotor and a magnet, which is then mounted on the tiltrotor. A switching controller including exclusive control modes for transitions between free-flight and perching is proposed. Lastly, we propose a simple yet effective strategy to ensure robust perching in the presence of measurement and control errors and avoid collisions with the perching site immediately after unperching. We validate the proposed framework in experiments where the tiltrotor successfully performs perching and unperching on/from a vertical surface during flight. We further show effectiveness of the proposed transition mode in the switching controller by ablation studies where large overshoot and even collision with a perching site occur. To the best of the authors' knowledge, this work presents the first autonomous aerial unperching framework using a fully actuated tiltrotor.

Aerial vehicles equipped with manipulators can serve contact-based industrial applications, where fundamental tasks like drilling and grinding often necessitate aerial platforms to handle heavy tools. Industrial environments often involve non-horizontal surfaces. Existing aerial manipulation platforms based on multirotors typically feature a fixed CoM (Center of Mass) within the rotor-defined area, leading to a considerable moment arm between the EE (End-Effector) tip and the CoM for operations on such surfaces. Carrying heavy tools at the EE tip of the manipulator with an extended moment arm can lead to system instability and potential damage to the servo actuators used in the manipulator. To tackle this issue, we present a novel aerial vehicle tailored for handling heavy tools on non-horizontal surfaces. In this work, we provide the platform's system design, modeling, and control strategies. This platform can carry heavy manipulators within the rotor-defined area during free flight. During interactions, the manipulator can shift towards the work surface outside the rotor-defined area, resulting in a displaced CoM location with a significantly shorter moment arm. Furthermore, we propose a method for automatically determining the manipulator's position to reach the maximum CoM displacement towards the work surface. Our proposed concepts are validated through simulations that closely capture the developed physical prototype of the platform.

Flying geckos are able to use their tails to stabilise their landings after crashing into trees at speeds of up to 13 miles per hour, a new study has revealed. A drone based on the remarkable crash landing capabilities of the small lizard opens the door to future airborne robots that can land on walls or upside down, according to the developers at the Max Planck Institute for Intelligent Systems in Stuttgart. They discovered that the colourful creatures use their tail to stabilise themselves after gliding head first into a tree trunk, stopping them falling to the ground. Corresponding author Dr Ardian Jusufi said structures similar to gecko tails could stabilise drones during a landing on a vertical surface. This could lead to robots that can land in inaccessible places, helping search and rescue after a landslide or building collapse, or during military operations, they said. Geckos' climbing abilities give them agility rarely surpassed in nature.

This review considers a problem in the development of mobile robot adhesion methods with vertical surfaces and the appropriate locomotion mechanism design. The evolution of adhesion methods for wall-climbing robots (based on friction, magnetic forces, air pressure, electrostatic adhesion, molecular forces, rheological properties of fluids and their combinations) and their locomotion principles (wheeled, tracked, walking, sliding framed and hybrid) is studied. Wall-climbing robots are classified according to the applications, adhesion methods and locomotion mechanisms. The advantages and disadvantages of various adhesion methods and locomotion mechanisms are analyzed in terms of mobility, noiselessness, autonomy and energy efficiency. Focus is placed on the physical and technical aspects of the adhesion methods and the possibility of combining adhesion and locomotion methods.

Jet engines can have up to 25,000 individual parts, making regular maintenance a tedious task that can take over a month per engine. Many components are located deep inside the engine and cannot be inspected without taking the machine apart, adding time and costs to maintenance. This problem is not only confined to jet engines, either; many complicated, expensive machines like construction equipment, generators, and scientific instruments require large investments of time and money to inspect and maintain. Researchers at Harvard University's Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS) have created a micro-robot whose electroadhesive foot pads, origami ankle joints, and specially engineered walking gait allow it to climb on vertical and upside-down conductive surfaces, like the inside walls of a commercial jet engine. The work is reported in Science Robotics.

Scientists have borrowed a few tricks from Mother Nature in order to create a drone capable of landing flush against a wall. The Multimodal Autonomous Drone (S-MAD) looks like a small airplane and flies like a glider, but on approaching a flat surface is able to change configuration to make a smooth, ricochet-free vertical landing -- much like a graceful bird or a large, unpleasant insect, depending on how this unsettling robotic behavior makes you feel. Created by researchers at Canada's University of Sherbrooke, the S-MAD uses microspines to attach itself to rough surfaces. These are commonly used on quadrotor drones, where landing is generally less of a problem. Fixed-wing landing presents more challenges, even before you throw perching into the mix, as the device needs to have slowed almost to a stop to prevent it from bouncing off the surface it's trying to land on.