Robotic Mechanisms Research Articles

Modeling and Compensation of Stiffness-Dependent Hysteresis for Stiffness-Tunable Tendon-Sheath Mechanism in Flexible Endoscopic Robots

Modeling and Compensation of Stiffness-Dependent Hysteresis for Stiffness-Tunable Tendon-Sheath Mechanism in Flexible Endoscopic Robots

Dynamic formulation and inertia fast estimation of a 5-DOF hybrid robot

As the main driving mechanism of a hybrid robot, the parallel mechanism is a nonlinear time-varying system. The load inertia of its actuated joints changes with the configuration of the robot. Analyzing and fitting the inertia variation is of great significance to the design and control of hybrid robots. By taking a hybrid robot named TriMule as an example, the variation of load inertia of each actuated joint in the whole workspace is first revealed based on the dynamic analyses of the robot. Then two methods based on the circular and elliptical membership are proposed to calculate fitted inertia over the whole workspace using inertia information at a few configurations. Finally, the fitting methods of the two membership functions are compared and discussed. The results show that the maximum value and global mean value of the fitting error of the elliptical membership method are 39.18% (51.23%) and 65.79% (81.25%) for actuated joint-1 (joint-2 and joint-3) lower than those of circular membership method, which promise a better global fitting accuracy. The proposed method can be used to estimate the joint load inertia or other control variables affected by inertia in a quick manner, allowing the algorithm to be easily integrated into the robot control system.

Design, modeling, and experiment of a multi-degree-of-freedom pneumatic soft bionic actuator

Drawing on the driving mechanism of biological muscles and combining the nonlinear hyperelastic characteristics of silicone rubber, a multi-degree-of-freedom pneumatic soft bionic actuator is designed, which can be used as the executing mechanism for soft robots and robotic arms. Using response surface analysis and numerical simulation algorithms, the optimal combination of structural dimensions parameters is determined with the maximum bending and torsion angles output by the actuator as the optimization objectives. Based on the idea of flexible mechanism Piecewise Constant Curvature (PCC) modeling, the kinematics equation of the actuator is derived. Analyze the equivalent motion structure of the actuator and establish a dynamic model of the actuator based on the Lagrange method. The physical model of the actuator is manufactured using rapid prototyping technology. Finally, experimental testing and analysis are conducted on the physical model to obtain the motion and dynamic characteristics curves and empirical formulas of the actuator, which are compared with theoretical and simulation results to verify that the pneumatic soft bionic actuator is feasible and effective. The above research methods, processes, and results can provide reference and inspiration for the research and implementation of pneumatic and hydraulic soft robots and gripping actuators for soft robotic arms.

Simulation study on four-wheeled mobile robot mechanisms using various performance criteria

In this paper, the performance criteria for various four-wheeled mobile robots that are crucial for assessing a robot’s fitness for mobility to successfully complete missions are introduced. The seven proposed performance indices, the root mean squared acceleration (RMSA), posture variance index (PVI), static stability margin (SSM), force angle stability margin (FASM), energy stability margin (ESM), friction requirement (μr), and velocity constraint violation (VCV), address the fluctuation, rollover, and slippage problems in four-wheeled mobile robots. The simulations considered a square bump-shaped obstacle, and the dimensions of the robot were based on nine simulation cases in a 3D environment. Additionally, a methodology for evaluating these seven criteria is outlined. To streamline the simulation process, Taguchi’s catalog of orthogonal arrays (OAs) was used for the experimental design, specifically L9 OA with four factors and three levels was used. Analysis of means (ANOM) was applied to assess the influence of each design factor on the seven criteria, leveraging the OA orthogonality. Finally, the sensitivity analysis and potential for evaluating general mobile robots in the future are discussed.

Fault-tolerant joint state feedback adaptive control for snake robots that move through random pole environments

ABSTRACT In unstructured terrain, snakes can move more efficiently by actively pushing and avoiding obstacles, a capability believed to be realized through a decentralized mechanism. Moreover, considering harsh and unpredictable rescue environments where snake robots are expected to be deployed, such as post-earthquake scenarios, some joint sensors are prone to failure. We propose a decentralized adaptation mechanism for snake robots to navigate through random pole environments. This mechanism integrates Fault-Tolerant Joint State Feedback Adaptive Control (FT-JSFAC) with Extended Curvature Derivatives control (ECD) and Angular Damping control (AD), leveraging the FT-JSFAC method to maintain operational robustness even when some joint sensors fail. To meet critical goals of adaptability, we utilize real-time angle and electrical current data from the robot's internal servo motors. Using this data, FT-JSFAC determines whether an obstacle is beneficial or detrimental to propulsion and then allows for decentralized torque adjustment to adapt to the environment. FT-JSFAC also employs historical data from functioning joints to compensate for erroneous sensor data, ensuring operational robustness even with joint sensor failure. Simulation experiments demonstrate that the proposed mechanism effectively adapts to environmental obstacles and maintains adaptability when one or two joint sensors fail.

PATENT ANALYSIS OF EXOSKELETON MECHANISMS AND WAY TO IMPROVE THEIR COMFORT. Continuation*

The issue of creating robotic anthropomorphic mechanisms called exoskeletons for humans is relevant. The exoskeleton design became practically possible due to technological developments, creating powerful computers, sensors, and detectors, collecting info about human movements, and advances in control theory. Introduction of available achievements in the domain of exoskeleton engineering and design, as well as exoskeleton parts and their control methods, protected by patents, to a general audience is the objective of the article. The research methods are analysis of patents and scientific publications on the topic of exoskeletons, and graphical processing of research results. The result of the conducted research is the survey of the patented exoskeletons available in the scientific world. It has been found that the available exoskeleton models are still not user-friendly enough. Therefore, the authors of the article developed and patented a model of an exoskeleton with variable-length links. The model of practical implementation of variable-length link based on using magneto-rheological fluid and adjusting the link stiffness by applying an external magnetic field has been proposed. The proposed model augments the exoskeleton user experience. It has been found that intense publication growth in scientific journals on researched topics started after 2011. The number of published exoskeleton patents increased almost tenfold in the past ten years by 2021. All these demonstrate significant interest in exoskeletons design.

Determination of the rotation axes of the artificial foot and ankle using a robotic gyroscopic mechanism

Determination of the rotation axes of the artificial foot and ankle using a robotic gyroscopic mechanism

Design of an Automatic Sealing Mechanism for Extraterrestrial Sample-Collecting Robot

Returning extraterrestrial samples to Earth for analysis is crucial for planetary geological research and resource utilization. However, during their return journey, these samples undergo significant environmental changes, such as varying pressure, temperature, impact, and vibration. Hence, a dependable sealing technique that preserves sample integrity without requiring high-powered tools is necessary. This article aims to develop an automatic sealing system for collecting extraterrestrial samples, conducting parametric design and mechanical analysis on two types of proposed sealing structures with minimal sealing force as the benchmark. Additionally, the system will undergo validation through sealing and leakage detection experiments. An automated sealing system, capable of storing samples in multiple sampling tubes, is assembled for the extraterrestrial sampling device.

Application of social entertainment robots based on machine learning algorithms and the Internet of Things in collaborative art performances

In terms of control strategies for social entertainment robots, advanced control system design was adopted in the study, aiming to enable robots to achieve efficient collaborative art performances. The control system is based on machine learning algorithms and Internet of Things technology, combined with the application of sensing technology, providing accurate environmental perception and real-time feedback mechanisms for robots. Considering the collaboration and interaction between robots and human actors, control strategies adapted to different scenes were designed by analyzing and understanding the needs of artistic performances. These strategies not only consider the robot’s own actions and performance, but also the interaction with human actors and the coordination with the entire performance scene. The control method in this article combines machine learning algorithms and sensing technology to enable robots to make intelligent decisions and action planning by learning and perceiving real-time environmental information. By modeling and simulating the structure and characteristics of the robot, precise planning and control of the robot’s motion trajectory can be achieved. Through dynamic modeling, it is possible to better understand the motion characteristics and energy consumption of robots, and to adjust and optimize their actions during the performance process.

Automation of 3D digital rolling circle amplification using a 3D-printed liquid handler

Automation of liquid handling is indispensable to improve throughput and reproducibility in biochemical assays. However, the incorporation of automated systems into laboratory workflows is often hindered by the high cost and complexity associated with building robotic liquid handlers. Here, we report a 3D-printed liquid handler based on a fluidic manifold, thereby obviating the need for complex robotic mechanisms. The fluidic manifold, termed a dispensing and aspirating (DA) device, comprises parallelized multi-pipette structures connected by distribution and aspiration channels, enabling the precise supply and removal of reagents, respectively. Leveraging the versatility of 3D printing, the DA device can be custom-designed and printed to fit specific applications. As a proof-of-principle, we engineered a 3D-printed liquid handler dedicated for 3D digital rolling circle amplification (4DRCA), an advanced biochemical assay involving multiple sample preparation steps such as antibody incubation, cell fixation, nucleic acid amplification, probe hybridization, and extensive washing. We demonstrate the efficacy of the 3D-printed liquid handler to automate the preparation of clinical samples for the simultaneous, in situ analysis of oncogenic protein and transcript markers in B-cell acute lymphoblastic leukemia cells using 4DRCA. This approach provides an effective and accessible solution for liquid handling automation, offering high throughput and reproducibility in biochemical assays.

Robotics Autonomous Systems (RAS) in Food Laboratories are the Future of Food Processing Industries: A Review

Recent advancements in robotics have witnessed significant progress in both industrial and mobile robotics, paving the way for a new era of automation. However, a paradigm shift is underway in robotics research, focusing on enhancing the interaction between humans and robots, termed as service robotics. This emerging field aims to cater to a wide array of human social needs by bridging the gap between man and machine. Traditionally, laboratory automation has been constrained by the rigid control mechanisms of computer-driven robots. Despite their utility, particularly in liquid handling tasks, many laboratory procedures remain only partially automated. Nonetheless, by breaking down laboratory processes into discrete unit operations and integrating them, overarching analysis schemes can be accomplished. The future of laboratory automation necessitates interdisciplinary skills, requiring scientists to blend biological knowledge with engineering expertise to fully exploit its potential. Simultaneously, a new wave of robotic innovations is permeating various sectors, from robot lawn mowers to autonomous vehicles, alongside smarter robots in manufacturing environments. This progression underscores the increasing reliance on automation, with future research endeavours expected to pivot towards leveraging laboratory automation to tackle novel scientific challenges. This abstract underscore the necessity for future scientists to acquire a comprehensive skill set that integrates both biological knowledge and engineering expertise. It highlights the trend towards greater automation in laboratory environments, representing the merging of scientific and engineering fields to tackle new research challenges.

Wireless Peristaltic Pump for Transporting Viscous Fluids and Solid Cargos in Confined Spaces

AbstractThe transport of fluids and solids is a vital process inside the human body, facilitated by the wave‐like motion in the lumen called peristalsis. However, peristalsis may be compromised due to tumor growth, resulting in difficulties in lumen motility. The dysmotility of the human lumen can result in blockages and pose numerous challenges, including aspiration in the lungs and reproductive issues in the female oviduct. Restoring peristalsis in medical devices, such as medical stents, can prevent device blockage and promote effective transport. Here, a wirelessly actuated soft robotic undulating pump designed to efficiently transport both viscous fluidic and solid cargos is proposed. The kinematics of the single sheet and the coordination between pairs are systematically designed to generate undulation and peristalsis, enabling the pumping of both liquids and solids. The integration of the undulating pump is demonstrated onto an esophageal stent. The same undulating motion‐based pumping mechanism can be adapted for usage in other organs, such as the female oviduct, thereby offering potential applications for treating lumen dysmotility in various diseases. The proposed wirelessly actuated robotic pumping mechanism holds promise in facilitating diverse implantable medical devices aimed at treating diseases characterized by impaired peristalsis and dysmotility.

PATENT ANALYSIS OF EXOSKELETON MECHANISMS AND WAY TO IMPROVE THEIR COMFORT

The issue of creating robotic anthropomorphic mechanisms called exoskeletons for humans is relevant. The exoskeleton design became practically possible due to technological developments, creating powerful computers, sensors, and detectors, collecting info about human movements, and advances in control theory. Introduction of available achievements in the domain of exoskeleton engineering and design, as well as exoskeleton parts and their control methods, protected by patents, to a general audience is the objective of the article. The research methods are analysis of patents and scientific publications on the topic of exoskeletons, and graphical processing of research results. The result of the conducted research is the survey of the patented exoskeletons available in the scientific world. It has been found that the available exoskeleton models are still not user-friendly enough. Therefore, the authors of the article developed and patented a model of an exoskeleton with variable-length links. The model of practical implementation of variable-length link based on using magneto-rheological fluid and adjusting the link stiffness by applying an external magnetic field has been proposed. The proposed model augments the exoskeleton user experience. It has been found that intense publication growth in scientific journals on researched topics started after 2011. The number of published exoskeleton patents increased almost tenfold in the past ten years by 2021. All these demonstrate significant interest in exoskeletons design.

Dynamic Analysis of the Locomotion Mechanism in Foxtail Robots: Frictional Anisotropy and Bristle Diversity.

This study investigated the locomotion mechanism of foxtail robots, focusing on the frictional anisotropy of tilted bristles under the same friction coefficient and propulsion strategy using bristle diversity. Through dynamic analysis and simulations, we confirmed the frictional anisotropy of tilted bristles and elucidated the role of bristle diversity in generating propulsive force. The interaction between contact nonuniformity and frictional anisotropy was identified as the core principle enabling foxtail locomotion. Simulations of foxtail robots with multiple bristles demonstrated that variations in bristle length, angle, and deformation contribute to propulsive force generation and environmental adaptability. In addition, this study analyzed the influence of major design parameters on frictional anisotropy, highlighting the critical roles of body height, bristle length, stiffness, reference angle, and friction coefficient. The proposed guidelines for designing foxtail robots emphasize securing bristle nonuniformity and inducing contact nonuniformity. The simulation framework presented enables the quantitative prediction and optimization of foxtail robot performance. This research provides valuable insights into foxtail robot locomotion and lays a foundation for the development of efficient and adaptive next-generation robots for diverse environments.

Analysis of Instantaneous Kinematic Properties Regarding the Shape of Robotic Mechanisms

Abstract A theoretical framework for analyzing instantaneous kinematic properties regarding the shape of robotic mechanisms is proposed. Conventional research on kinematic analysis regarding the shape has been conducted with the primary goal of approximating a target shape. In contrast, this study does not set a target shape, and instantaneous kinematic properties regarding the shape formed by multiple reference links are analyzed. The properties provide information about the shape change that is easy to achieve and about the controllability of the shape. Furthermore, in contrast to the standard kinematic analysis of robot manipulators that assumes having a single hand link configuration with respect to the base link, the kinematic analysis in this study is free from this assumption. When analyzing instantaneous kinematic properties regarding the shape, it is crucial to decompose motions of reference links into rigid and nonrigid components. After formulating this decomposition, the Jacobian matrices that relate active joint velocities and nonrigid motions are defined. The indices of instantaneous kinematic properties regarding the shape are defined on the basis of the Jacobian matrices. Moreover, application examples using the defined indices are demonstrated.

Towards a high-energy efficiency world: Assessing the impact of artificial intelligence on urban energy efficiency

Global warming has increased the frequency of natural disasters, making enhancing energy efficiency an inevitable choice to address the worsening global climate risks. Whether industrial robots, as a crucial component of artificial intelligence, can contribute to improving energy efficiency remains a subject of debate. This study employs the SBM and super-efficiency SBM models to assess the energy efficiency of 262 Chinese cities from 2010 to 2020. We investigate the impact and mechanisms of industrial robots at the city level on energy efficiency. The research findings indicate that the application of industrial robots promotes enhanced energy efficiency, which remains robust after subjecting it to a battery of tests, including SYS-GMM and instrumental variable analyses. However, a significant nonlinear relationship exists between industrial robot utilization and energy efficiency, with diminishing marginal effects. Mechanism analysis reveals that the fundamental mechanisms facilitating this improvement are the digital economy, industrial structural adjustments, and innovations in green technology. Heterogeneity analysis suggests that industrial robots have a more pronounced impact on cities with higher energy efficiency, greater manufacturing levels in resource-dependent areas, and lower population densities. Furthermore, the application of industrial robots can influence the energy efficiency of neighboring regions through spatial spillover effects.

Design and experiment of multi-locomotion tensegrity mobile robot

Multi-locomotion tensegrity mobile robots have garnered significant attention in recent research due to their strong terrain adaptability and high stiffness-to-mass ratio. However, the lack of effective design method limits the application range of these robots. In this article, a mechanism design method for the multi-locomotion tensegrity mobile robot is proposed. Firstly, based on the characteristics of worms, mechanism design objectives for the tensegrity robot are put forward from three perspectives, namely bionics, motion law and tensegrity characteristics. Accordingly, the mechanism design process is conducted from two sections in terms of the design of multi-locomotion tensegrity units and the splicing of the identical units. In the mechanism design for the tensegrity units, the rod distribution is firstly determined on compliance with the proposed design objectives, followed by the determination of cable distribution with force-balance analysis method. On this basis, two identical multi-locomotion tensegrity units are axially spliced, and a series of multi-locomotion tensegrity robotic mechanisms can be acquired naturally. Finally, examples are provided, and simulations and experiments are conducted to demonstrate the effectiveness of the proposed mechanism design method.

Physical Integrated Digital twin-based Interaction Mechanism of Artificial Intelligence Rehabilitation Robots Combining Visual Cognition and Motion Control

Physical Integrated Digital twin-based Interaction Mechanism of Artificial Intelligence Rehabilitation Robots Combining Visual Cognition and Motion Control

Nonlinear optimal control for robotic exoskeletons with electropneumatic actuators

Nonlinear optimal control for robotic exoskeletons with electropneumatic actuators

Human–robot mechanics model using hip torque identification with a dual-arm nursing-care transfer robot

In response to the growing demand for robotic interventions to mitigate the profound physical strain experienced by caregivers during transfers, dual-arm robotic systems have emerged as a focal point of interest in the caregiving community due to their adaptability and versatility. However, the accuracy of existing human–robot mechanics model is insufficient, impacting the execution of transfer tasks. To enhance the model’s precision, an improved model is proposed, integrating hip torque identification. This proposed methodology involves the simplification of the human structure based on the kinematic attributes associated with the embrace of individuals by robotic arms and the subsequent computation of its inertial parameters. Accordingly, the application of D’Alembert’s principle is employed to analyze the impact of embracing motion, human posture, and the position of human–robot contact on the forces exerted on the human. This culminates in the establishment of a model. Considering the static indeterminacy predicament inherent in the model, a biomechanical data set is curated for the dual-arm transfer scenario. Leveraging this data set, a deep neural network utilizing multilayer perceptron is trained to accurately identify hip torque, thereby improving the model. Accordingly, a robotic transfer platform featuring dual arms is developed and trailed on six subjects with varying anatomical profiles. The results show that the constructed model has high accuracy. This study provides critical mechanics insights for dual-arm transfer tasks, offering potential application value in the field of nursing and rehabilitation.