Autonomous Recovery Research Articles

A Session Type System for Asynchronous Unreliable Broadcast Communication

Session types are formal specifications of communication protocols, allowing protocol implementations to be verified by typechecking. Up to now, session type disciplines have assumed that the communication medium is reliable, with no loss of messages. However, unreliable broadcast communication is common in a wide class of distributed systems such as ad-hoc and wireless sensor networks. Often such systems have structured communication patterns that should be amenable to analysis by means of session types, but the necessary theory has not previously been developed. We introduce the Unreliable Broadcast Session Calculus, a process calculus with unreliable broadcast communication, and equip it with a session type system that we show is sound. We capture two common operations, broadcast and gather, inhabiting dual session types. Message loss may lead to non-synchronised session endpoints. To further account for unreliability we provide with an autonomous recovery mechanism that does not require acknowledgements from session participants. Our type system ensures soundness, safety, and progress between the synchronised endpoints within a session. We demonstrate the expressiveness of our framework by implementing Paxos, the textbook protocol for reaching consensus in an unreliable, asynchronous network.

Autonomous Landing of Quadrotor Unmanned Aerial Vehicles Based on Multi-Level Marker and Linear Active Disturbance Reject Control.

Landing on unmanned surface vehicles (USV) autonomously is a critical task for unmanned aerial vehicles (UAV) due to complex environments. To solve this problem, an autonomous landing method is proposed based on a multi-level marker and linear active disturbance rejection control (LADRC) in this study. A specially designed landing board is placed on the USV, and ArUco codes with different scales are employed. Then, the landing marker is captured and processed by a camera mounted below the UAV body. Using the efficient perspective-n-point method, the position and attitude of the UAV are estimated and further fused by the Kalman filter, which improves the estimation accuracy and stability. On this basis, LADRC is used for UAV landing control, in which an extended state observer with adjustable bandwidth is employed to evaluate disturbance and proportional-derivative control is adopted to eliminate control error. The results of simulations and experiments demonstrate the feasibility and effectiveness of the proposed method, which provides an effective solution for the autonomous recovery of unmanned systems.

Autonomous Recovery Control of Biomimetic Robotic Fish Based on Multi-Sensory System

Autonomous Recovery Control of Biomimetic Robotic Fish Based on Multi-Sensory System

Aircraft Upset Recovery Strategy and Pilot Assistance System Based on Reinforcement Learning

The upset state is an unexpected flight state, which is characterized by an unintentional deviation from normal operating parameters. It is difficult for the pilot to recover the aircraft from the upset state accurately and quickly. In this paper, an upset recovery strategy and pilot assistance system (PAS) based on reinforcement learning is proposed. The man–machine closed-loop system was established and the upset state, such as a high angle of attack and large attitude angle, was induced. The upset recovery problem was transformed into a sequential decision problem, and the Markov decision model of upset recovery was established by taking the deflection change of the control surface as the action. The proximal policy optimization (PPO) algorithm was selected for the strategy training. The adaptive pilot model and the reinforcement learning method proposed in this paper were used to make the aircraft recover from the upset state. Based on the correspondence between the flight state, the recovery method, and the recovery result, the aircraft upset recovery safety envelopes were formed, and the four-level upset recovery PAS with alarm warning, coordinated control, and autonomous recovery modes was constructed. The results of the digital virtual flight simulation and ground flight test show that compared with a traditional single pilot, the aircraft upset recovery strategy, the upset recovery safety envelopes, and the PAS established in this study could reduce the handling burden of the pilot and improve the success rate and effect of upset recovery. This research has certain theoretical reference values for flight safety and pilot training.

A Machine Learning App for Monitoring Physical Therapy at Home.

Shoulder rehabilitation is a process that requires physical therapy sessions to recover the mobility of the affected limbs. However, these sessions are often limited by the availability and cost of specialized technicians, as well as the patient's travel to the session locations. This paper presents a novel smartphone-based approach using a pose estimation algorithm to evaluate the quality of the movements and provide feedback, allowing patients to perform autonomous recovery sessions. This paper reviews the state of the art in wearable devices and camera-based systems for human body detection and rehabilitation support and describes the system developed, which uses MediaPipe to extract the coordinates of 33 key points on the patient's body and compares them with reference videos made by professional physiotherapists using cosine similarity and dynamic time warping. This paper also presents a clinical study that uses QTM, an optoelectronic system for motion capture, to validate the methods used by the smartphone application. The results show that there are statistically significant differences between the three methods for different exercises, highlighting the importance of selecting an appropriate method for specific exercises. This paper discusses the implications and limitations of the findings and suggests directions for future research.

Trajectory Planning and Control Design for Aerial Autonomous Recovery of a Quadrotor

One of the most essential approaches to expanding the capabilities of autonomous systems is through collaborative operation. A separated lift and thrust vertical takeoff and landing mother unmanned aerial vehicle (UAV) and a quadrotor child UAV are used in this study for an autonomous recovery mission in an aerial child–mother unmanned system. We investigate the model predictive control (MPC) trajectory generator and the nonlinear trajectory tracking controller to solve the landing trajectory planning and high-speed trajectory tracking control problems of the child UAV in autonomous recovery missions. On this basis, the estimation of the mother UAV movement state is introduced and the autonomous recovery control framework is formed. The suggested control system framework in this research is validated using software-in-the-loop simulation. The simulation results show that the framework can not only direct the child UAV to complete the autonomous recovery while the mother UAV is hovering but also keep the child UAV tracking the recovery platform at a speed of at least 11 m/s while also guiding the child UAV to a safe landing.

STUDY OF ADDITIVES FOR SELF-HEALING OF CEMENT SHEATH

The article discusses a study of cement sheath integrity improvement in oil and gas wells. This problem has been studied for more than 40 years. Nevertheless, every year it inextricably linked with the solution of current problems that challenge drilling specialists. Therefore, the search for solutions to problems in this area has great potential and prospects for further improvement. There are three conceptual approaches to the self-healing of cement stone: self-healing systems based on capsules (granules), in a vessel (fiber) shell and without shells. There is also a definition proposed by the Union of Laboratories and Experts in Building Materials. According to this concept, self-healing can occur during autogenous (natural) process, in which the filling of cement cracks occurs due to its own fund of non-hydrated particles when contact with water. Self-healing can also be autonomous (artificial, due to the introduction of additives such as polymers, bacteria and other components capable of either expanding or producing a substance that fills the void space under certain environmental conditions). However, despite the absence of auxiliary materials, autogenous healing is limited by the size of the cracks formed. Experience also shows that autonomous recovery also has negative aspects, which are associated with the characteristics of a particular material and medium - an activator. Therefore, in each case, the approach to solving the problem should be specific and unique. becomes more and more relevant due to the constant deterioration of mining and geological conditions in the process of drilling new wells. The process of adaptation to new conditions is After a series of successful studies aimed at the effect of water-oil-swelling additives on the self-healing ability of cement stone, the focus of the study was shifted to the problem of integrity of gas and gas condensate wells. In this regard, the study provides a detailed step-by-step description of the various processes aimed at finding a solution to the problem. The process of selecting a modifying additive with an assessment of the swelling ability to obtain the effect of self-healing cement stone in difficult mining and geological conditions is considered. Tests of additives in various conditions and environments are carried out. Attempts are made to create an experimental stand that allows simulating well conditions and evaluating the effect of stone restoration when creating artificial cracks. This study makes a significant contribution to the search and understanding of the performance of various additives in the formation environment. The creation of a test equipment is the first step towards modeling formation conditions at the surface. Further modernization of the stand will allow for more accurate tests and significantly reduce the time for selecting reagents. Thus, the use of this technology will improve the quality of well casing, as well as the safety of work in environmental terms.

A highlight removal method for autonomous recovery of cable-free seismographs in field environments

The cable-free seismograph is an instrument for capturing seismic wave signals, which is popularly employed in underground resource exploration tasks in complex field environments due to its high flexibility. However, the efficiency of exploration operations is low because the arrangement and recovery of instruments are done manually. Therefore, autonomously arranging and recovering cable-free seismographs will hold great significance. Nevertheless, the instrument surface will produce highlight under intense illumination in field environments, which can have a negative impact on the accuracy of segmentation and contour extraction of the instrument. It will significantly reduce the visual positioning accuracy of the instrument and ultimately fail in recovery tasks. To address this problem, we analyze the characteristics of highlight on cable-free seismographs in field environments and develop a method to remove the highlight by weighting the color features of the non-highlight pixels in the neighborhoods of highlight pixels. We realize the detection of highlight pixels based on the classical modified specular-free model and propose an image terrain map model to select the weighted neighborhoods of highlight pixels to ensure that no background pixels are involved in the process of highlight removal. The experimental results show that our method meets the requirements for contour extraction and object segmentation in the autonomous instrument recovery tasks. Furthermore, it outperforms currently existing highlight removal methods in the task of highlight removal for cable-free seismographs in field environments.

Bi-material sinusoidal beam-based temperature responsive multistable metamaterials

The ability of materials to adapt to changing environments is attractive for various applications, ranging from deployable structures to soft robots. In this work, we develop a multistable metamaterial that allows for autonomous recovery and programmable deformation in response to varying temperatures. The tunable multi-stability is achieved by incorporating a bi-material sinusoidal beam as the constituent element of the metamaterial. The mechanical response of the bi-material beam is explored theoretically. A phase diagram of its temperature induced bistability-to-monostability transition is obtained, validated by experiments and finite element simulations. With the phase diagram, the bi-material beam based building blocks of the metamaterial can be designed to transit from one stable state to another one via snap-through after compression, and return to its first stable configuration when the temperature rises above a critical temperature. Numerical and experimental results show clearly from the force–displacement-temperature path that the developed metamaterial possesses temperature-induced recoverability and programmable deformation. Construction of bi-material sinusoidal beams with more triggering temperatures for stability transition is also discussed.

An underwater docking system based on UUV and recovery mother ship: design and experiment

The research focuses on the autonomous docking of unmanned underwater vehicles (UUV) to a recovery mother ship. Firstly, a novel fork-pole docking station was designed, which could operate independently or be transported onboard a recovery mother ship. Subsequently, a docking guidance scheme combining long-range acoustic guidance and short-range opti-acoustic guidance was proposed. Acoustic guidance employed ultra-short baseline sonar and acoustic beacons to measure relative position information, while optical guidance utilized camera and L-shaped light arrays to obtain relative pose information. Then, an opti-acoustic complementary recovery control strategy was developed to address the instability of acoustic signals. Finally, experimental tests were conducted in a pool to evaluate the performance of the proposed recovery docking system in both static and dynamic docking scenarios, which demonstrated that the docking system was capable of achieving fully autonomous recovery of UUV. Furthermore, the experimental data analysis shows that the presented recovery control strategy is effective and feasible.

Responsive polymer thin films

Responsive polymer thin films

Fabrication of high-quality microcapsules containing ionic liquid for application in self-healing conductive materials

Conductive materials inevitably develop micro-cracks during processing or use, which seriously impairs the performance and lifetime of their associated devices. Autonomous recovery of conductivity can greatly improve in-service reliability and extend service life. Herein, microcapsules containing conductive ionic liquid (IL) were successfully synthesized using a novel microencapsulation technique via integrating electrostatic spraying and interfacial polymerization (ES-IP), and their high potential for conductivity restoration of conductive pastes for printed circuits was verified. The prepared ionic liquid microcapsules (IL-MCs) have good dispersibility, great solidity, and tunable properties. Self-healing conductive composites were prepared by incorporating the synthesized microcapsules into the conductive slurry and the effect of microcapsule content in the matrix on the restoration was investigated. The conductivity recovery tests show that IL-MCs recover the conductivity of the damaged samples with an efficiency of about 96%. While the restoration efficiency remains essentially stable with increasing the microcapsule content, the chance of restoration increases. When the microcapsule content was 20%, the probability of the damaged samples being autonomously repaired is about 84%. It proves that the successful microencapsulation of IL using the ES-IP technique broadens the applications of ILs in conductive materials.

Deep Reinforcement Learning-Based Failure-Safe Motion Planning for a 4-Wheeled 2-Steering Lunar Rover

The growing trend of onboard computational autonomy has increased the need for self-reliant rovers (SRRs) with high efficiency for unmanned rover activities. Mobility is directly associated with a successful execution mission, thus fault response for actuator failures is highly crucial for planetary exploration rovers in such a trend. However, most of the existing mobility health management systems for rovers have focused on fault diagnosis and protection sequences that are determined by human operators through ground-in-the-loop solutions. This paper presents a special four-wheeled two-steering lunar rover with a modified explicit steering mechanism, where each left and right wheel is controlled by only two actuators. Under these constraints, a new motion planning method that combines reinforcement learning with the rover’s kinematic model without the need for dynamics modeling is devised. A failure-safe algorithm is proposed to address the critical loss of mobility in the case of steering motor failure, by expanding the devised motion planning method, which is designed to ensure mobility for mission execution in a four-wheeled rover. The algorithm’s performance and applicability are validated through simulations on high-slip terrain scenarios caused by steering motor failure and compared with a conventional control method in terms of reliability. This simulation validation serves as a preliminary study toward future works on deformable terrain such as rough or soft areas and optimization of the deep neural network’s weight factor for fine-tuning in real experiments. The failure-safe motion planning provides valuable insights as a first-step approach toward developing autonomous recovery strategies for rover mobility.

Communication and Cross‐Regulation between Chemically Fueled Sender and Receiver Reaction Networks**

AbstractNature connects multiple fuel‐driven chemical/enzymatic reaction networks (CRNs/ERNs) via cross‐regulation to hierarchically control biofunctions for a tailored adaption in complex sensory landscapes. Herein, we introduce a facile example of communication and cross‐regulation among two fuel‐driven DNA‐based ERNs regulated by a concatenated RNA transcription regulator. ERN1 (“sender”) is designed for the fuel‐driven promoter formation for T7 RNA polymerase, which activates RNA transcription. The produced RNA can deactivate or activate DNA in ERN2 (“receiver”) by toehold‐mediated strand displacement, leading to a communication between two ERNs. The RNA from ERN1 can repress or promote the fuel‐driven state of ERN2; ERN2 in turn feedbacks to regulate the lifetime of ERN1. Furthermore, the incorporation of RNase H allows for RNA degradation and enables the autonomous recovery of ERN2. We believe that concatenation of multiple CRNs/ERNs provides a basis for the design of more elaborate autonomous regulatory mechanisms in systems chemistry and synthetic biology.

Communication and Cross-Regulation between Chemically Fueled Sender and Receiver Reaction Networks.

Nature connects multiple fuel-driven chemical/enzymatic reaction networks (CRNs/ERNs) via cross-regulation to hierarchically control biofunctions for a tailored adaption in complex sensory landscapes. Herein, we introduce a facile example of communication and cross-regulation among two fuel-driven DNA-based ERNs regulated by a concatenated RNA transcription regulator. ERN1 ("sender") is designed for the fuel-driven promoter formation for T7 RNA polymerase, which activates RNA transcription. The produced RNA can deactivate or activate DNA in ERN2 ("receiver") by toehold-mediated strand displacement, leading to a communication between two ERNs. The RNA from ERN1 can repress or promote the fuel-driven state of ERN2; ERN2 in turn feedbacks to regulate the lifetime of ERN1. Furthermore, the incorporation of RNase H allows for RNA degradation and enables the autonomous recovery of ERN2. We believe that concatenation of multiple CRNs/ERNs provides a basis for the design of more elaborate autonomous regulatory mechanisms in systems chemistry and synthetic biology.

Cooperative Multiagent Deep Reinforcement Learning for Reliable Surveillance via Autonomous Multi-UAV Control

CCTV-based surveillance using unmanned aerial vehicles (UAVs) is considered a key technology for security in smart city environments. This paper creates a case where the UAVs with CCTV-cameras fly over the city area for flexible and reliable surveillance services. UAVs should be deployed to cover a large area while minimize overlapping and shadow areas for a reliable surveillance system. However, the operation of UAVs is subject to high uncertainty, necessitating autonomous recovery systems. This work develops a multi-agent deep reinforcement learning-based management scheme for reliable industry surveillance in smart city applications. The core idea this paper employs is autonomously replenishing the UAV's deficient network requirements with communications. Via intensive simulations, our proposed algorithm outperforms the state-of-the-art algorithms in terms of surveillance coverage, user support capability, and computational costs.

Dopamine Receptors Gene Expression Pattern and Locomotor Improvement Differ Between Female and Male Zebrafish During Spinal Cord Auto Repair.

The dopaminergic system, a spinal cord (SC) motor circuit regulator, is administrated by sexual hormones and evolutionary conserved in all vertebrates. Accordingly, we hypothesized that the dopamine receptor (DAR) expression pattern may be dissimilar in female and male zebrafish SC auto repair. We implemented an uncomplicated method to induce spinal cord injury (SCI) on fully reproductive adult zebrafish, in both genders. SCI was induced using a 28-gauge needle at 9th-10th vertebra without skin incision. Thereupon, lesioned SC was harvested for DAR gene expression analysis; zebrafish were tracked routinely for any improvement in swim distance, speed, and their roaming capabilities/preference. Our findings revealed discrepancies between drd2a, drd2b, drd3, drd4a, and drd4b expression patterns at 1, 7, and 14 days postinjury (DPI) between female and male zebrafish. The receptors were mostly upregulated at 7 DPI in both genders, whereas drd2a and drd2b were mostly maximized in females. Surprisingly, drd3 was measured greater even in intact SC in males. In addition, female zebrafish were able to swim farther distances more accelerated, in multiple directions, by engaging more caudal muscles compared with males, of course with no statistical significance. Indeed, females were able to generate whole-body rotation and move forward using the muscles downstream to the lesion site, whereas the coordinated movement in males was accomplished by rostral muscles. In conclusion, there are differences in DAR gene expression pattern throughout SC autonomous recovery between adult female and male zebrafish, and also, female locomotion seems to ameliorate more rapidly.

Self‐healable electromagnetic interference shielding composite films with temperature and strain dual responsiveness

AbstractResponsive films have attracted much attention in recent years for their great potentials in actuators, smart devices, robots, communication and anti‐counterfeit, and so on. In this work, multifunctional films combining self‐healing, responsiveness, and electromagnetic interference (EMI) shielding ability are successfully fabricated via incorporating carbon nanotubes (CNTs) into hydroxyl terminated polybutadiene (HTPB), which is dynamically crosslinked by boric acid (BA). The HTPB‐BA substrate shows excellent self‐healing ability at room temperature, which facilitates the autonomous recovery of electric conductivity and mechanical strength of the composite films. Dual responsiveness to temperature and strain are found for these composite films that the electric resistance actively changes in responding to variation of temperature and strain. More encouragingly, the composite films have excellent EMI shielding ability that the effectiveness is beyond 28 dB, satisfying the commercial application. The EMI shielding efficiency is responsive to temperatures too. These responsive, EMI shielding, and self‐healable composite films may offer promising and broad prospects in the field of flexible electronics and protection of sensitive instruments.

Effect of cryotherapy on post-exercise cardiac autonomic recovery in mixed martial arts (MMA) fighters: A Randomized Clinical Trial

Background: Cryotherapy brings benefits for muscle recovery and reduction of lactate thresholds in fighters; however, the effect of cryotherapy on the autonomous cardiac recovery (ACR) of wrestlers is not yet defined in the scientific literature. Objective: To analyze the effect of cryotherapy on ACR after simulated combat exercise in mixed martial arts (MMA) fighters. Methods: Crossover randomized clinical trial with a sample of 17 MMA fighters (male, age >18 years). There was simulated combat of three rounds of MMA; each round lasted 5-min, there were the 60s between rounds. ACR was assessed by resting heart rate (RHR), which was monitored by a portable Polar-FT1® device. We measured RHR in the interval between the rounds at the 30s and 60s of rest in the conditions: without cryotherapy (Control), application of an ice pack in the thoracic region (TC); Immersion of feet in ice water (FC). Results: At 30-s of RHR, the control condition was better than FC to reduce RHR in rounds 1 and 2 (p<0.05; η2p:0.28). At the 60s of RHR, the control condition was better than FC and TC (p<0.05; η2p:0.32). The control condition had a better RHR recovery rate than the FC condition after rounds one (η2p: 0.23), two (η2p: 0.46), and three (η2p: 0.27) (p<0.05). The TC condition did not show differences concerning the control and FC conditions. Conclusion: Cryotherapy applications in the thoracic region and by complete immersion of the feet did not generate significant effects on the ACR of MMA fighters.

Path following Control of an Underactuated Catamaran for Recovery Maneuvers

This paper focuses on the autonomous recovery maneuvers of an unknown underactuated practical catamaran, which returns to its initial position corresponding to the man overboard (MOB) by simply adjusting the rate of turn. This paper investigates the completion of model-based path following control for not only the traditional Williamson turn, but also complex recovery routes under time-varying disturbances. The main difficulty of model-based path following control for predicting the hydrodynamic derivatives of a practical catamaran was solved by the approximated calculation of a diagonal matrix. The second key problem of differential calculation for an underactuated model in the case of complex reference trajectories under severe disturbances was investigated. Even though this paper employs a diagonal matrix with unknown nonlinear terms, the experimental test using a small craft with payloads by remote control demonstrated the sway force per yaw moment in turning cases. Adaptive backstepping mechanisms with unknown parameters were proven by the Lyapunov theory as well as the passive-boundedness of the sway dynamics, guaranteeing the stability of sway motion in the case of unavailable sway control. The effectiveness of the algorithms of the guiding concept and error dynamics is demonstrated by the numerical simulations.