关键词： 森林防火   履带平台   机器人   Adams   动力学仿真  

摘要： 针对森林的复杂环境,为满足森林防火机器人履带平台的越障性能要求,本文提出一种基于椭圆定理的可变形履带平台。该履带平台通过摆臂的转动来调节履带形状,具有更好的越障性能和张紧能力。为充分了解履带平台的越障性能,在履带平台的运动机理分析基础上,对履带平台典型障碍进行动力学分析,得到越障过程的最大理论值。根据理论值结合林区实际情况计算,用Adams建立仿真平台,对攀爬高地及跨越沟壑的状态进行仿真实验,验证表明履带平台可攀爬200 mm高度台阶,跨越255 mm宽度沟壑,具有良好的越障性能。

关键词： MEMS mirror   micro-robotics   electrothermal actuation   LiDAR  

摘要： Light detection and ranging (LiDAR) has been widely used for airborne surveillance and autonomous driving. The ability of robotics or even micro-robotics can be drastically enhanced if equipped with LiDAR, but very light and small LiDAR must be used. Micro-robots have sizes close to birds or insects, and almost all existing LiDAR are too heavy and too large for them. In this work, a novel MEMS LiDAR, with its optical scanner separated from its base, is proposed and demonstrated. The scanner head will be carried by a moving micro-robot while the LiDAR base is fixed on the ground. There is a thin, flexible optical/electrical cable connecting the scanner head to the base. The scanner head consists of a MEMS mirror and a rod lens, which weighs only 10 g and measures under 4 cm long. The MEMS mirror has an aperture of 1.2 mm x 1.4 mm and can scan a field of view (FoV) of 9 degrees x 8 degrees. As the micro-robot and the optical scanner head moves with respect to the optical receiver, an IMU (inertial measurement unit) has been embedded in the scanner head to track the motion and an algorithm has been developed to reconstruct the true point clouds. The movable head LiDAR can acquire 400 points per second and detect targets up to 35 cm away. A micro-robot can carry the scanner head while it is moving, and the point clouds can be generated at the LiDAR base. This new LiDAR configuration enables ranging, mapping, tracking, and zoom-in scanning for micro-robots.

关键词： 关节电机   行星减速器   动力学仿真  

摘要： 关节电机是足式机器人核心部件之一,其动态响应直接影响着机器人的性能。其中的行星减速器属于精密机械传动机构,其传动精度与关键零件的变形密切相关。利用Adams建立了关节电机行星减速器刚柔耦合动力学仿真模型,模拟在启动过程中的瞬态输出特性。模型中对关键零件进行柔性化处理,设置各零件间的运动副约束,利用Hertz接触理论计算了行星轮与太阳轮、内齿圈的接触刚度系数。仿真结果表明,关节电机的动态特性与加速时间和惯性载荷密切相关,较大的加速时间与较小的惯性载荷有利于提高其动态性能。

关键词： Cognition   Perception   Reaching and grasping task   Visual servoing   Sensing approach   Learning approach   Gripping approach  

摘要： Interaction between a robot and its environment requires perception about the environment, which helps the robot in making a clear decision about the object type and its location. After that, the end effector will be brought to the object's location for grasping. There are many research studies on the reaching and grasping of objects using different techniques and mechanisms for increasing accuracy and robustness during grasping and reaching tasks. Thus, this paper presents an extensive review of research directions and topics of different approaches such as sensing, learning and gripping, which have been implemented within the current five years.

关键词： Bipedal robots   Hybrid systems   Port-Hamiltonian dynamics   Fractional sliding surface   Finite-time control   Disturbance estimator  

摘要： In this paper, disturbance reconstruction and robust trajectory tracking control of biped robots with hybrid dynamics in the port-Hamiltonian form is investigated. A new type of Hamiltonian function is introduced, which ensures the finite-time stability of the closed-loop system. The proposed control system consists of two loops: an inner and an outer loop. A fractional proportional-integral-derivative filter is used to achieve finite-time convergence for position tracking errors at the outer loop. A fractional-order sliding mode controller acts as a centralized controller at the inner-loop, ensuring the finite-time stability of the velocity tracking error. In this loop, the undesired effects of unknown external disturbance and parameter uncertainties are compensated using estimators. Two disturbance estimators are envisioned. The former is designed using fractional calculus. The latter is an adaptive estimator, and it is constructed using the general dynamic of biped robots. Stability analysis shows that the closed-loop system is finite-time stable in both contact-less and impact phases. Simulation studies on three types of biped robots (i.e., two-link walker, RABBIT biped robot, and flat-feet biped robot) demonstrate the proposed controller's tracking performance and disturbance rejection capability. (C) 2021 Elsevier B.V. All rights reserved.

关键词： artificial intelligence   machine learning   deep learning   digital twin   digital shadow   Industry 4.0 & nbsp   sustainability   sustainable smart manufacturing   robotics   review  

摘要： Digital twin (DT) and artificial intelligence (AI) technologies have grown rapidly in recent years and are considered by both academia and industry to be key enablers for Industry 4.0. As a digital replica of a physical entity, the basis of DT is the infrastructure and data, the core is the algorithm and model, and the application is the software and service. The grounding of DT and AI in industrial sectors is even more dependent on the systematic and in-depth integration of domain-specific expertise. This survey comprehensively reviews over 300 manuscripts on AI-driven DT technologies of Industry 4.0 used over the past five years and summarizes their general developments and the current state of AI-integration in the fields of smart manufacturing and advanced robotics. These cover conventional sophisticated metal machining and industrial automation as well as emerging techniques, such as 3D printing and human-robot interaction/cooperation. Furthermore, advantages of AI-driven DTs in the context of sustainable development are elaborated. Practical challenges and development prospects of AI-driven DTs are discussed with a respective focus on different levels. A route for AI-integration in multiscale/fidelity DTs with multiscale/fidelity data sources in Industry 4.0 is outlined.

关键词： Coupling dynamics   control   legged robot   simulation  

摘要： This article develops a coupling dynamic method focusing on the coupling relationship between the leg and the body of a legged robot. The dynamic equation of the method reflects the mechanism between an active operating part and a passive moving part among a multibody system. It is used to adjust the position and posture of the body by driving the motion of the joint of the leg, thereby solving problems such as rollover or overturning of the body during its walking or running. Because the robot has enough redundant degrees of freedom, we can design other additional constraints to achieve coordinated control of the robot. The developed dynamic modeling method is applied for two control tasks. By the results of numerical simulations, the effectiveness of this method is verified.

关键词： wearable assistive robotics   wearable sensors   machine learning   human factors   standards  

摘要： Wearable assistive robotics is an emerging technology with the potential to assist humans with sensorimotor impairments to perform daily activities. This assistance enables individuals to be physically and socially active, perform activities independently, and recover quality of life. These benefits to society have motivated the study of several robotic approaches, developing systems ranging from rigid to soft robots with single and multimodal sensing, heuristics and machine learning methods, and from manual to autonomous control for assistance of the upper and lower limbs. This type of wearable robotic technology, being in direct contact and interaction with the body, needs to comply with a variety of requirements to make the system and assistance efficient, safe and usable on a daily basis by the individual. This paper presents a brief review of the progress achieved in recent years, the current challenges and trends for the design and deployment of wearable assistive robotics including the clinical and user need, material and sensing technology, machine learning methods for perception and control, adaptability and acceptability, datasets and standards, and translation from lab to the real world.

关键词： brain biopsy   frame-less stereotactic surgery   registration   robot-assisted surgery   stereoelectroencephalography  

摘要： Background: Safety, efficacy and efficiency of neurosurgical robots are defined by their design (i.e., framed and non-framed) and procedural workflow (PW) (from image to surgery). The present study describes the quality indicators of three different robots in brain and spine surgery. Methods: This single-centre study enrolled 252 patients over a 10-year period. Safety (complication rate) and efficacy (diagnostic yield, pedicle screw placement) were determined. Predictors of workflow efficiency (e.g., skin-to-skin) were evaluated and compared to conventional techniques (neuronavigation, stereotaxy). Results: All robots showed excellent reliability (97.5%-100%) with low complication rates (4.5%-5.3%) and high efficacy (94.7%-97.7%). Robotics demonstrated a better time-efficiency than neuronavigation. However, there was no shortening of surgery time compared to conventional stereotaxy. Time-efficiency differed significantly between framed and non-framed workflows. Conclusion: While all neurosurgical robots were reliable, safe and efficacious, there were significant differences in time-efficiency. PWs should be improved to increase the acceptance of robotics in neurosurgery.

关键词： anti-freezing hydrogel   diverse surface adhesion   human-machine interface   ionic skin   soft robotics   stretchable electronics  

摘要： Natural living systems such as wood frogs develop tissues composed of active hydrogels with cryoprotectants to survive in cold environments. Recently, hydrogels have been intensively studied to develop stretchable electronics for wearables and soft robots. However, regular hydrogels are inevitably frozen at the subzero temperature and easily dehydrated, and have weak surface adhesion. Herein, a novel hydrogel-based ionic skin (iSkin) capable of strain sensing is demonstrated with high toughness, high stretchability, excellent ambient stability, superior anti-freezing capability, and strong surface adhesion. The iSkin consists of a piece of ionically and covalently cross-linked tough hydrogel with a thin bioadhesive layer. With the addition of biocompatible cryoprotectant and electrolyte, the iSkin shows good conductivity in wide ranges of relative humidity (15-90%) and temperature (-95-25 degrees C). In addition, the iSkin can adhere firmly to diverse material surfaces under different conditions, including cloth fabric, skin, and elastomers, in both dry and wet conditions, at subzero temperature, and/or with dynamic movement. The iSkin is demonstrated for applications including strain sensing on both human body and winter coat, human-machine interaction, motion/deformation sensing on a soft gripper and a soft robot at extremely cold conditions. This work provides a new paradigm for developing high-performance artificial skins for wearable sensing and soft robotics.