High-speed Locomotion Research Articles

Histamine-tuned subicular circuit mediates alert-driven accelerated locomotion in mice

The locomotive action involves diverse coordination, necessitating the integration of multiple motor neural circuits. However, the precise circuitry mechanism governing emotion-driven accelerated locomotion remains predominantly elusive. Here we dissect projections from the tuberomammillary nucleus (TMN) to subiculum (SUB) which promote alert-driven accelerated locomotion. We find that TMN histaminergic neurons respond to high-speed locomotion in both natural and alert acceleration. The TMN-SUB circuit is sufficient but not essential for amplifying accelerated locomotion from low to high-speed movement in basal condition, but it is both sufficient and necessary in alert condition for modulating accelerated locomotion during high-speed escape behavior. TMN histaminergic neuron activates SUB glutamatergic “fast locomotor cell” that projects to retrosplenial granular cortex (RSG) mainly through histamine H2 receptor (H2R). This study reveals the critical role of the histamine-tuned SUB circuit in alert-driven accelerated locomotion in mice, providing a theoretical foundation for comprehending neural circuit mechanisms of instinctive behaviors under alert.

Integral resonant negative derivative feedback suppression control strategy for nonlinear dynamic vibration behavior model

One of the major problems in robotics research has been developing an actuator system for extremely dynamic-legged robots. High torque density and the capacity to control dynamic physical interactions are two design requirements for high-speed locomotion that are challenging for conventional actuators used in manufacturing applications to meet. To address this system and apply the desired control to reach the best stability position, the robot's foot was simulated with the Van der Pol equations, applied the required control, and studied that application. This work describes the actions of a new novel control mechanism known as the Integral Resonant Negative Derivative Feedback (IRNDF) controller, which reduces the vibration response of a double Van der Pol oscillator subjected to external excitations. This unique controller combines integral resonant control (IRC) and negative derivative feedback (NDF) controllers to provide a new controller effect for double Van der Pol oscillators. The multiple scale perturbation technique (MSPT) has been applied to solve the controlled system analytically. The MATLAB and MAPLE programs have been used to complete and clarify all of the numerical talks. The frequency response curves have been used to study the impact that altering the parameter values had on the amplitude. The controlled system vibration amplitude is governed by frequency-response equations (FREs), which have been constructed. In the vibration system, the IRC, NDF, and IRNDF controllers were compared to see which one was the best. Numerical results show that the unique IRNDF controller is the best at reducing oscillations and decreasing amplitude values. The effects of the effective parameters on the controlled system have been identified. The frequency-response equation that was derived has been used to plot the various response curves for the framework that show the stable and unstable zones when the controller is off and on. Lastly, excellent agreement between the derived numerical findings and the analytical ones was observed. Lastly, utilizing time histories and response curves to compare analytical and numerical solutions was fascinating and significant.

Variable-stiffness-morphing wheel inspired by the surface tension of a liquid droplet.

Wheels have been commonly used for locomotion in mobile robots and transportation systems because of their simple structure and energy efficiency. However, the performance of wheels in overcoming obstacles is limited compared with their advantages in driving on normal flat ground. Here, we present a variable-stiffness wheel inspired by the surface tension of a liquid droplet. In a liquid droplet, as the cohesive force of the outermost liquid molecules increases, the net force pulling the liquid molecules inward also increases. This leads to high surface tension, resulting in the liquid droplet reverting to a circular shape from its distorted shape induced by gravitational forces. Similarly, the shape and stiffness of a wheel were controlled by changing the traction force at the outermost smart chain block. As the tension of the wire spokes connected to each chain block increased, the wheel characteristics reflected those of a general circular-rigid wheel, which has an advantage in high-speed locomotion on normal flat ground. Conversely, the modulus of the wheel decreased as the tension of the wire spoke decreased, and the wheel was easily deformed according to the shape of obstacles. This makes the wheel suitable for overcoming obstacles without requiring complex control or sensing systems. On the basis of this mechanism, a wheel was applied to a two-wheeled wheelchair system weighing 120 kilograms, and the state transition between a circular high-modulus state and a deformable low-modulus state was realized in real time when the wheelchair was driven in an outdoor environment.

Compliant control of biomimetic parallel torso based on musculoskeletal control

Compliant movement and stress buffering of the torso are particularly important for state transition during high-speed locomotion in quadrupedal mammals. Currently, passive compliant control is commonly used in bionic torsos of quadruped robots, while active compliant control remains rare and immature. In previous research, we developed an active six-Degree-of-Freedom (DoF) bionic parallel torso. In this paper, we establish a muscle model that includes four biomechanical elements representing muscle characteristics (muscle force-fiber length and muscle velocity relationships) from the perspective of biology and physiology. We propose a musculoskeletal model that simulates the biological motion control system to control the compliant movement of each joint of the parallel mechanism. This model includes: 1) a neural equilibrium point controller that represents the transmission of motion commands, 2) activation dynamics that describe the activation of stimulated muscles, 3) contraction dynamics that emphasize the biomechanical characteristics of muscle tendons, 4) skeletal dynamics that describe bone movement. The effects of flexor and extensor stimulation on muscle activation, force, length, and velocity were analyzed. The results showed that both the flexor and extensor muscles will contract after corresponding stimulation. Furthermore, adjusting muscle stimulation through the musculoskeletal model can drive the parallel mechanism to reach the desired position. The musculoskeletal control method based on external force feedback can establish new torque balance in joints and drive the parallel torso to achieve compliant movements. Simulation and experiments have demonstrated the feasibility of the musculoskeletal control method. This method enhances the compliance and environmental adaptability of the parallel torso in practical applications.

Research on Dynamic Modeling Method and Flying Gait Characteristics of Quadruped Robots with Flexible Spines.

In recent years, both domestic and international research on quadruped robots has advanced towards high dynamics and agility, with a focus on high-speed locomotion as a representative motion in high-dynamic activities. Quadruped animals like cheetahs exhibit high-speed running capabilities, attributed to the indispensable role played by their flexible spines during the flight phase motion. This paper establishes dynamic models of flexible spinal quadruped robots with different degrees of simplification, providing a parameterized description of the flight phase motion for both rigid-trunk and flexible-spine quadruped robots. By setting different initial values for the spine joint and calculating the flight phase results for both types of robots at various initial velocities, the study compares and analyzes the impact of a flexible spine on the flight phase motion of quadruped robots. Through comparative experiments, the research aims to validate the influence of a flexible spine during the flight phase motion, providing insights into how spine flexibility affects the flight phase motion of quadruped robots.

The Therapeutic Effects and Mechanisms of Gardenoside on Inflammatory Injury via the INS/NF-κB Pathway in a T2DM Zebrafish Model

Objective: This study utilized the zebrafish model to investigate the therapeutic effects of gardenoside on inflammatory damage in type 2 diabetes mellitus (T2DM) through the INS/NF-κB pathway. Methods: The study employed 7-8-month-old AB strain zebrafish and induced T2DM models by continuous exposure to a 2% glucose solution for 14 days. Control, model, gardenoside low-, medium-, and high-dose groups (2.5 mg/L, 5 mg/L, 10 mg/L), and a metformin group were established. Parameters such as zebrafish body weight, fasting blood glucose levels, and behavioral analyses were monitored. Fructosamine levels were measured using ELISA, while real-time polymerase chain reaction (Real-time PCR) was employed to assess the relative expression levels of INS, IRS, NF-κB, IL-1β, and IL-6 genes. Intestinal histological examination was conducted to observe inflammation levels. Results: Compared to the control group, the model group exhibited significantly increased blood glucose levels, weight gain, and fructosamine content. High-speed locomotion time increased, while low-speed locomotion time decreased. Relative expression levels of INS, NF-κB, IL-1β, and IL-6 genes were elevated (P < 0.0001), whereas IRS relative expression levels decreased (P E0.001). In comparison to the model group, the gardenoside and metformin groups demonstrated reduced blood glucose levels and no significant change in body weight. The gardenoside low and medium dose groups, as well as the metformin group, showed reduced high-speed locomotion time and increased low-speed locomotion time. The relative expression levels of INS, NFκB, IL-1β, and IL-6 genes in the gardenoside and metformin groups decreased (P < 0.01 or P < 0.0001), while IRS relative expression levels increased (P < 0.001 or P < 0.0001). Conclusion: Gardenoside may suppress inflammatory responses, alleviate insulin resistance, and ameliorate diabetes-related inflammatory symptoms, potentially through the regulation of the INS/NF-κB signaling pathway.

Bio-Inspired Untethered Robot-Sensor Platform for Minimally Invasive Biomedical Sensing.

Conventional catheter- or probe-based in vivo biomedical sensing is uncomfortable, inconvenient, and sometimes infeasible for long-term monitoring. Existing implantable sensors often require an invasive procedure for sensor placement. Untethered soft robots with the capability to deliver the sensor to the desired monitoring point hold great promise for minimally invasive biomedical sensing. Inspired by the locomotion modes of snakes, we present here a soft kirigami robot for sensor deployment and real-time wireless sensing. The locomotion mechanism of the soft robot is achieved by kirigami patterns that offer asymmetric tribological properties that mimic the skin of the snake. The robot exhibits good deployability, excellent load capacity (up to 150 times its own weight), high-speed locomotion (0.25 body length per step), and wide environmental adaptability with multimodal movements (obstacle crossing, locomotion in wet and dry conditions, climbing, and inverted crawling). When integrated with passive sensors, the versatile soft robot can locomote inside the human body, deliver the passive sensor to the desired location, and hold the sensor in place for real-time monitoring in a minimally invasive manner. The proof-of-concept prototype demonstrates that the platform can perform real-time impedance monitoring for the diagnosis of gastroesophageal reflux disease.

Stable skill improvement of quadruped robot based on privileged information and curriculum guidance

Quadruped robots have attracted many researchers due to their unique advantages. In the field of control, deep reinforcement learning (DRL) saves the complex and tedious design of traditional control algorithms and motivates the robot to learn the motion patterns by itself, which is a promising alternative approach. However, due to the lack of prior information that is difficult to obtain in the physical world, policy usually exhibits a single motion state when faced with multiple scenarios. In this paper, we adopt a teacher–student policy architecture that uses the student policy to implicitly identify the teacher policy containing a privileged information, enabling the robot to adjust its motion depending on the environment it is in. We propose the synthetic terrain-command curriculum that assigns different levels of command curriculum depending on the difficulty of the terrain, which is useful for improving policy adaptation and stability. Policy is often trapped in local optima due to the nonlinearity of the robot system and unreasonable parameters. We propose a self-correction mechanism to jump out of this state in time, so that the policy can be steadily improved. We demonstrate our policy on the real quadruped platform named SDUQuad-48, and the results show that the learned policy exhibits state-of-the-art performance in both high-speed locomotion and complex terrain adaptation.

A single neuron in C. elegans orchestrates multiple motor outputs through parallel modes of transmission

Animals generate a wide range of highly coordinated motor outputs, which allows them to execute purposeful behaviors. Individual neurons in the circuits that generate behaviors have a remarkable capacity for flexibility as they exhibit multiple axonal projections, transmitter systems, and modes of neural activity. How these multi-functional properties of neurons enable the generation of adaptive behaviors remains unknown. Here, we show that the HSN neuron in C.elegans evokes multiple motor programs over different timescales to enable a suite of behavioral changes during egg laying. Using HSN activity perturbations and invivo calcium imaging, we show that HSN acutely increases egg laying and locomotion while also biasing the animals toward low-speed dwelling behavior over minutes. The acute effects of HSN on egg laying and high-speed locomotion are mediated by separate sets of HSN transmitters and different HSN axonal compartments. The long-lasting effects on dwelling are mediated in part by HSN release of serotonin, which is taken up and re-released by NSM, another serotonergic neuron class that directly evokes dwelling. Our results show how the multi-functional properties of a single neuron allow it to induce a coordinated suite of behaviors and also reveal that neurons can borrow serotonin from one another to control behavior.

Experimental analysis of the sweepback angle effect on the thrust generation of a robotic penguin wing

Penguins have evolved excellent swimming skills as diving birds, benefiting from their agile wings. This paper experimentally analyzes the effects of the wing sweepback angle on thrust generation using a robotic penguin wing. A developed wing mechanism that can realize penguin-like flapping and feathering motion was used for actuating five alternative wing models, with different sweepback angles ranging from 0° to 50°. Force measurements under a steady water flow were conducted for both fixed and flapping states for all wing models. The results showed that small sweepback angles of 30° or less in the fixed state caused a steep lift curve and a moderate sweepback angle of 30° produced the largest lift-to-drag ratio. In the flapping state, the smaller sweepback wings generated a larger net thrust for the same wing motion, whereas the larger-sweepback wings produced more thrust under the same Strouhal number. The findings also revealed that larger sweepback wings more easily achieve the maximum net thrust in terms of less angle-of-attack control. In contrast, the hydrodynamic efficiency was not greatly affected by the sweepback. Regardless of the sweepback, the trend of the efficiency increasing with increasing flow speed indicates that the penguin wings can be more suitable for high-speed locomotion for higher hydrodynamic efficiency.

Learning quadrupedal locomotion on deformable terrain.

Simulation-based reinforcement learning approaches are leading the next innovations in legged robot control. However, the resulting control policies are still not applicable on soft and deformable terrains, especially at high speed. The primary reason is that reinforcement learning approaches, in general, are not effective beyond the data distribution: The agent cannot perform well in environments that it has not experienced. To this end, we introduce a versatile and computationally efficient granular media model for reinforcement learning. Our model can be parameterized to represent diverse types of terrain from very soft beach sand to hard asphalt. In addition, we introduce an adaptive control architecture that can implicitly identify the terrain properties as the robot feels the terrain. The identified parameters are then used to boost the locomotion performance of the legged robot. We applied our techniques to the Raibo robot, a dynamic quadrupedal robot developed in-house. The trained networks demonstrated high-speed locomotion capabilities on deformable terrains: The robot was able to run on soft beach sand at 3.03 meters per second although the feet were completely buried in the sand during the stance phase. We also demonstrate its ability to generalize to different terrains by presenting running experiments on vinyl tile flooring, athletic track, grass, and a soft air mattress.

Application of yaw dampers with frequency-selective damping to improve the locomotive adaptability to low/high conicity stability

High-speed locomotives are prone to the carbody or bogie hunting under extreme wheel-rail contact conditions, which can cause negative impacts on vehicle dynamics performance. The influence of key suspension parameters on the carbody lateral ride comfort and bogie lateral acceleration is investigated by the multi-objective optimization and Sobol global sensitivity analysis methods, which is based on the Radial Basis Function Neutral Network surrogate model. The results illustrate that the yaw damper damping is sensitive to the two hunting stabilities, but conventional yaw dampers with fixed damping fail to satisfy both the stability demands simultaneously. Therefore, this paper presents a damping-adjustable yaw damper integrating an FSD (frequency-selective damping) valve to guarantee the lateral stability especially in abnormal wheel-rail contact states, and the application effects of the FSD yaw damper for the locomotive are researched by dynamics simulations. The results show that the FSD yaw damper can improve the adaptability of the locomotive to both the low and high wheel-rail contact conicity service conditions compared with the conventional yaw dampers.

Ultrafast small-scale soft electromagnetic robots

High-speed locomotion is an essential survival strategy for animals, allowing populating harsh and unpredictable environments. Bio-inspired soft robots equally benefit from versatile and ultrafast motion but require appropriate driving mechanisms and device designs. Here, we present a class of small-scale soft electromagnetic robots made of curved elastomeric bilayers, driven by Lorentz forces acting on embedded printed liquid metal channels carrying alternating currents with driving voltages of several volts in a static magnetic field. Their dynamic resonant performance is investigated experimentally and theoretically. These robust and versatile robots can walk, run, swim, jump, steer and transport cargo. Their tethered versions reach ultra-high running speeds of 70 BL/s (body lengths per second) on 3D-corrugated substrates and 35 BL/s on arbitrary planar substrates while their maximum swimming speed is 4.8 BL/s in water. Moreover, prototype untethered versions run and swim at a maximum speed of 2.1 BL/s and 1.8 BL/s, respectively.

OpenFish: Biomimetic design of a soft robotic fish for high speed locomotion

We present OpenFish: an open source soft robotic fish which is optimized for speed and efficiency. The soft robotic fish uses a combination of an active and passive tail segment to accurately mimic the thunniform swimming mode. Through the implementation of a novel propulsion system that is capable of achieving higher oscillation frequencies with a more sinusoidal waveform, the open source soft robotic fish achieves a top speed of 0.85m/s. Hereby, it outperforms the previously reported fastest soft robotic fish by 27%. Besides the propulsion system, the optimization of the fish morphology played a crucial role in achieving this speed. In this work, a detailed description of the design, construction and customization of the soft robotic fish is presented. Hereby, we hope this open source design will accelerate future research and developments in soft robotic fish.

THEORETICAL STUDIES OF THE POSSIBILITY OF OPERATING AN INTERMEDIATE RAIL FASTENING OF THE KPP-5 TYPE ON PROMISING SECTIONS OF UKRAINIAN RAILWAYS, WHERE IT IS PLANNED TO INTRODUCE HIGH-SPEED TRAFFIC

The introduction of high-speed traffic in the railways of Ukraine is one of the priorityareas of development of the domestic railway industry. Foreign experience in the operation of highspeed and high-speed lines has a positive impact on the overall economic performance of thesecountries by increasing the mobility of means of production and human resources. In addition,increasing speeds requires the introduction of new types of rolling stock and railway structures withunconditional provision of the required level of safety. This is possible only through a comprehensiveapproach to these issues, both through experimental tests and theoretical calculations. This studytheoretically assessed the possibility of operating intermediate rail fasteners type KPP-5 Ukrainianproduction in areas where in the medium term, it is planned to increase speeds, i.e. to reach a levelof more than 160 km/h. To achieve this goal, multivariate calculations were performed to determinethe stress state that penetrates the elements of the railway track under the action of rolling stock.Four types of high-speed locomotives and electric trains, which have been operated on the railwaylines of the European Union for a long time, were selected as units of account in the study. For alltypes of rolling stock (locomotives and high-speed electric trains) for which calculations wereperformed, the obtained values of stresses acting in the elements of the railway track do not exceedthe allowable. That is, in terms of strength, intermediate rail fasteners type KPP-5 Ukrainianproduction can be operated in straight sections at speeds over 160 km / h with heat-treated rails typeR65 on reinforced concrete sleepers with laying diagram 1840 pcs / km with gravel ballast 40 cmthick. Analytical comparison of the level of stresses arising in the railway track elements in lines withintermediate rail fastening type KPP-5 made in Ukraine and the W30 rail fastening systemmanufactured by Vossloh showed approximately the same level of stress in the railway track elements.However, it should be noted that the above conclusions are only theoretical in nature and for thefinal determination of the possibility of operation of the intermediate rail fastening type KPP-5 inreal conditions (at speeds greater than 160 km / h) requires additional experimental studies.

Three Characteristics of Cheetah Galloping Improve Running Performance Through Spinal Movement: A Modeling Study

Cheetahs are the fastest land animal. Their galloping shows three characteristics: small vertical movement of their center of mass, small whole-body pitching movement, and large spine bending movement. We hypothesize that these characteristics lead to enhanced gait performance in cheetahs, including higher gait speed. In this study, we used a simple model with a spine joint and torsional spring, which emulate the body flexibility, to verify our hypothesis from a dynamic perspective. Specifically, we numerically searched periodic solutions and evaluated what extent each solution shows the three characteristics. We then evaluated the gait performance and found that the solutions with the characteristics achieve high performances. This result supports our hypothesis. Furthermore, we revealed the mechanism for the high performances through the dynamics of the spine movement. These findings extend the current understanding of the dynamic mechanisms underlying high-speed locomotion in cheetahs.

Legs as linkages: an alternative paradigm for the role of tendons and isometric muscles in facilitating economical gait.

ABSTRACTConsiderable attention has been given to the spring-like behaviour of stretching and recoiling tendons, and how this can reduce the work demanded from muscle for a given loss–return cycling of mechanical energy during high-speed locomotion. However, even completely isometric muscle–tendon units have the potential to act as tension struts, forming links in linkages that avoid the demand for mechanical work-cycling in the first place. Here, forelimb and hindlimb structures and geometries of quadrupeds are considered in terms of linkages that avoid mechanical work at the level of both the whole limb and the individual muscles. The scapula, isometric serratus muscles and forelimb can be viewed as a modified Roberts' straight-line mechanism that supports an approximately horizontal path of the body with vertically orientated forces, resulting in low work demand at the level of both limb and muscle. Modelled isometric triceps brachii inserting to the olecranon form part of a series of four-bar linkages (forelimb) and isometric biceps femoris cranial, rectus femoris and tensor fascia latae form part of a series of six-bar linkages (hindlimb), in both cases potentially resulting in straight-line horizontal motion, generating appropriate moments about shoulder and hip to maintain vertical ground reaction forces and again low mechanical work demand from the limb. Analysing part of the complexity of animal limb structure as linkages that avoid work at the level of both the whole limb and the supporting muscles suggests a new paradigm with which to appreciate the role of isometric muscle–tendon units and multiple muscle origins.

A feedforward air-conditioning energy management method for high-speed railway sleeper compartment

In this paper, we propose a feedforward air conditioning temperature control method for high-speed railway locomotives with sleeper compartments to improve energy efficiency. First, we construct the geometric model of two typical types of compartments and three types of passengers. Then, based on the analysis of possible passenger layout patterns in each compartment, we utilize computational fluid dynamics simulations to calculate the optimal air volume for each pattern. The optimal air volume is calculated to guarantee the passenger comfort level and reduce the energy cost. In addition, we adopt an image recognition method to detect the number and types of passengers in each compartment. Passenger layout patterns serve as independent variables to determine the corresponding optimal air volume. Finally, numerical simulations were conducted to verify the effectiveness of the proposed method.

Mechanism analysis of cheetah’s high-speed locomotion based on digital reconstruction

As the fastest land animal, cheetah has important reference significance for the research of high-speed quadruped robots in terms of its body structure, motion characteristics and control mechanism. In this paper, we used digital reconstruction to analyze the mechanism of the cheetah’s high-speed movement. Considering the body size and quality of a real cheetah, a simplified virtual model of cheetah was built. Using the D-H method, the kinematics and dynamics of the cheetah’s leg mechanism were established. By using the foot trajectory data of the cheetah’s running gait obtained from biological research, each joint angle, virtual leg length, leg-to-ground contact angle, leg energy, joint torque, and the manipulability of the leg mechanism were analyzed and compared in the time dimension. Finally, the high-speed motion law of engineering guiding significance was extracted.

Suspension parameters matching of high-speed locomotive based on stability/comfort Pareto optimization

Suspension parameters optimisation and matching is a very important topic in the design of railway vehicles, and a reasonable combination of suspension parameters is the most powerful guarantee for safe and stable operation. However, most of the existing research about that still belongs to single-objective optimisation and pays little attention to the matching relationship between different suspension parameters, which has plenty of limitations. Therefore, the lateral stability and ride comfort of a certain type of domestic high-speed locomotive are studied and optimised through the genetic algorithm NSGA-II, to find the optimal lateral dynamic performance. It can be found that there is an obvious contradiction between linear stabilities under low-conicity and high-conicity conditions, but a strong positive correlation between low-conicity stability and lateral ride comfort in a low-conicity condition. Besides, the matching relation of the six key suspension parameters is explored employing data analysis methods, such as global sensitivity and clustering analysis, and three types of parameter combinations are proposed. In addition, the speed robustness and rail cant robustness regarding the three types of parameter combinations are analyzed, and the lateral dynamic performance characteristics of each parameter combination type are summarised.