Soft medical robotics: clinical and biomedical applications,challenges, and future directions

Bioinspired soft robotics allow for safer clinical interactions with human patients but conventional, hard robots, which are often built with rigid materials and complex control systems, compromise tissue integrity, freedom of movement, conformability, and overall human bio-compatibility. Soft, compliant materials intrinsically reduce mechanical complexity, accommodate their usage environment, and provide great practical potential for medical device developments. Previous review papers have generally covered the topics of materials, manufacturing processes, actuator modeling and control, and current trends. Here, we focus on recent developments in soft robotic applications for the medical field including advances in cardiac devices, surgical robots, and soft rehabilitation and assistance devices. In medical applications, soft robotic devices not only expedite the evolution of minimally invasive surgery but also improve the bio-compatibility of rehabilitation and assistance devices. Here, we evaluate design requirements, mechanisms, achievements and challenges in these key areas. Of particular note, this paper concludes with a discussion on advances in 3D printing and adapting neural networks for modeling and control frameworks that have facilitated the development of faster and less expensive soft medical devices.     

Digital twin-based industrial cloud robotics: Framework,control approach and implementation

Industrial cloud robotics (ICR) integrates cloud computing with industrial robots (IRs). The capabilities of industrial robots can be encapsulated as cloud services and used for ubiquitous manufacturing. Currently, the digital models for process simulation, path simulation, etc. are encapsulated as cloud services. The digital models in the cloud may not reflect the real state of the physical robotic manufacturing systems due to inaccurate or delayed condition update and therefore result in inaccurate simulation and robotic control. Digital twin can be used to realize fine sensing control of the physical manufacturing systems by a combination of high-fidelity digital model and sensory data. In this paper, we propose a framework of digital twin-based industrial cloud robotics (DTICR) for industrial robotic control and its key methodologies. The DTICR is divided into physical IR, digital IR, robotic control services, and digital twin data. First, the robotic control capabilities are encapsulated as Robot Control as-a-Service (RCaaS) based on manufacturing features and feature-level robotic capability model. Then the available RCaaSs are ranked and parsed. After manufacturing process simulation with digital IR models, RCaaSs are mapped to physical robots for robotic control. The digital IR models are connected to the physical robots and updated by sensory data. A case is implemented to demonstrate the workflow of DTICR. The results show that DTICR is capable to synchronize and merge digital IRs and physical IRs effectively. The bidirectional interaction between digital IRs and physical IRs enables fine sensing control of IRs. The proposed DTICR is also flexible and extensible by using ontology models.     

Nonlinear trilateral teleoperation stability analysis subjected to time-varying delays

A trilateral teleoperation system facilitates the collaboration of two users to share control of a single robot in a remote environment. While various applications of shared-control trilateral haptic teleoperation systems have recently emerged, they have mostly been studied in the context of single-DOF, LTI robotic systems. On the other hand, robotic manipulators with multiple degrees of freedom (DOF) and therefore nonlinear dynamics have recently found many applications such as in robotic-assisted surgery and therapy, space exploration and navigation systems. In this paper, considering the full nonlinear dynamical models of multi-DOF robots, stability analysis of a dual-user haptic teleoperation system is considered over a communication network subjected to asymmetrical time varying delays and through a dominance factor suitable for trainer–trainee applications. Stability in free motion and contact motion and asymptotic position tracking of the trilateral haptic teleoperation system in free motion are proven via Lyapunov stability analysis and Barbalat's lemma where operators and the environment are assumed to be passive. Simulation and experimental results concerning robot position tracking and user-perceived forces for three 2-DOF robots and experimental analysis of user-perceived stiffnesses for three 3-DOF robots validate the theoretical findings pertaining to the system stability and demonstrate the efficiency of the proposed controller.     

State-of-the-Art control strategies for robotic PiH assembly

Nowadays, industrial robots have been widely applied for performing position-controlled tasks with minimum contact such as spot welding, spray painting, packing, and material handling; however, performing high-tolerance assembly tasks still poses a great challenge for robots because of various uncertainties of the parts to be assembled such as fixtures, end effector tools, or axes. From this perspective, the advancement of research and development has led to cutting-edge robotic technologies for industrial applications. To understand the technological trend of industrial robots, investigated the state-of-the-art robotic assembly technologies to identify the limitations of existing works and clarify future research directions in the field. This paper especially interested on typical peg-in-hole (PiH) assemblies, as PiH methods provide insights for further development of robot assemblies. The assembly control strategies for PiH operations is classified by based on the types and features of the assemblies, and the literature in terms of the contributions of these studies is compared to PiH assembly. Finally, the control strategies for robotic PiH assemblies are discussed in detail, and the limitations of the current robotic assembly technologies are discussed to identify the future direction of research for the control of robotic assembly.     

Adaptable compliance or variable stiffness for robotic applications [From the Guest Editors]

Exciting new robots are being developed that will operate in a different environment from traditional industrial factories or research laboratories. Researchers are working worldwide to create robots that are integrated into our daily lives. For the advancement of these new robots, compliant, safe, and new actuators are one of the important issues turning energy into safe motion. The biological counterpart is the muscle tendon structure that has functional performance characteristics and a neuromechanical control systemthat has far more superior capabilities. The superior power to weight ratio, force to weight ratio, and sensing characteristics limit the development of machines that can match motion, safety, and energy efficiency of a human or other animal. One of the key differences of biological systems is their adaptable compliance or variable stiffness compared with the traditional stiff electrical drives used for the standard industrial robotic applications, which require accurate, reference-trajectory tracking.More and more applications such as robots in close human or robot proximity, legged autonomous robots, and rehabilitation devices and prostheses demand a different set of design specifications, for which the use of compliant actuators can be beneficial as compared with the traditional stiff actuation schemes.     

An evaluation of machine guarding techniques for robot guarding

An increasing number of problems caused by the use of industrial robots should be expected due to the dramatically increasing population of robots today. In this paper, machine guarding functions and techniques are reviewed. The possibilities of transferring the concepts of machine guarding to robotic systems are then analyzed. The analysis shows that most of the guarding techniques are still applicable to industrial robots with modifications to accommodate differences. A set of guidelines for installing safeguarding devices is also presented. Research is need in the areas of guarding techniques for robotic cells, new sensor development, and sensor reliability, fusion, and coordination problems.     

基于PLCopen的六轴工业机器人运动控制功能块设计

针对工业机器人控制系统的开放性要求,设计符合PLCopen规范的六轴工业机器人运动控制功能块。基于CodeSys软件开发环境,结合SMC_CNC库中数组、结构体和功能块,采用IEC61131-3编程语言开发了六轴工业机器人运动控制功能块,包含：坐标变换、正逆运动变换、直线与圆弧插补运动等;在此基础上,开发了一系列机器人运动控制指令和可视化编程界面。最后,以埃夫特ER50六轴工业机器人为实验对象,采用研制的机器人运动控制器,实施机器人编程控制实验,结果表明所开发的机器人运动控制功能块及其指令达到了设计要求。     

视觉伺服机器人对运动目标操作的研究

机器人视觉伺服系统是机器人领域一重要的研究方向，它的研究对于开发手眼协调的机器人在工业生产、航空航天等方面的应用有着极其重要的意义．本文着眼于视觉伺服机器人操作运动目标这一问题，分析了建立此类系统的控制结构并指明其特点；同时，详细地阐述了三个组成环节：视觉图像处理、预测及滤波、视觉控制器的研究方法和现状．最后，分析了今后的研究趋势．     

The state of the art of testing standards for integrated robotic systems

Technology standards facilitate the transparency in market and the supplies of products with good quality. For manufacturers, standards make it possible to reduce the costs by mass production, and enhance system adaptabilities through integrating system modules with the standardized interfaces. However, International standards on industrial robots such as ISO-9283 were developed in 1998, and they have not updated since then. Due to every-increasing applications of robots in complex systems, there is an emerging need to advance existing standards on robots for a broader scope of system components and system integration. This paper gives an introduction of the endeavors by National Institute of Standards and Technology (NIST); especially, it overviews the recent progresses on the standardized tests of robotic systems and components. The presented work aims to identify the limitations of existing industrial standards and clarify the trend of technology standardizations for industrial robotic systems.     

机器人视觉伺服系统的标定

机器人视觉伺服系统是机器人领域一项重要的研究方向,它的研究对于开发手眼协调的机器人在工业生产、航空航天等方面的应用有着重要的意义。本文针对机器人视觉伺服系统的特点,对典型的标定算法进行了分类和比较,最后对标定方法进行了总结。     

Design of a modular assembly of four-footed robots with multiple functions

Modern industries use many types of robots. In addition to general robotic arms, bipedal, tripedal, and quadrupedal robots, which were originally developed as toys, are gradually being used for multiple applications in manufacturing processes. This research begins with establishing the platform for four-footed robots with multiple functions, high sensitivity, and modular assembly and this is how a fundamental model of the industrial robots is constructed. Under additional loads, the four feet of the quadrupedal robot reinforce its carrying ability and reliability compared to bipedal or tripedal robots, which helps it to carry more objects and enhances functionality. Based on different requirements and demands from the manufacturing processes, the highly sensitive four-footed robot provides an expandable interface to add different sensing components. In addition, when combined with a wireless communication module or independent 1.2 GHz radio frequency CCD wireless image transmission system, the user can control the robot remotely and instantly. The design helps the four-footed robot to expand its applications. By assembling and disassembling modules and changing the sensing components, the highly sensitive four-footed robot can be used for different tasks. Moreover, the remote control function of the robot will increase interaction with human beings, so it can become highly become involved in people's lives. The platform of the four-footed robot will become a design reference for the commercialization of different industrial robots, and it will provide the design of industrial robots with more options and useful applications.     

Neural computing increases robot adaptivity

The limited adaptivity of current robots is preventing their widespreadapplication. Since the biological world offers a full range of adaptive mechanisms working at different scales, researchers have turned to it for inspiration. Among the several disciplines trying to reproduce these mechanisms artificially, this paper concentrates on the field of Neural Networks and its contributions to attain sensorimotor adaptivity in robots. Essentially this type of adaptivity requires tuning nonlinear mappings on the basis of input-output information. After briefly reviewing the fundamentals of neural computing, the paper describes several experimental robotic systems relying on the following adaptive mappings: inverse kinematics, inverse dynamics, visuomotor and force-control mappings. Finally, the main trends in the evolution of neural computing are highlighted, followed by some remarks drawn from the surveyed robotic applications.     

Modelling the dynamics of industrial robots for milling operations

Using industrial robots as machine tools is targeted by many industries for their lower cost and larger workspace. Nevertheless, performance of industrial robots is limited due to their mechanical structure involving rotational joints with a lower stiffness. As a consequence, vibration instabilities, known as chatter, are more likely to appear in industrial robots than in conventional machine tools. Commonly, chatter is avoided by using stability lobe diagrams to determine the stable combinations of axial depth of cut and spindle speed. Although the computation of stability lobes in conventional machine tools is a well-studied subject, developing them in robotic milling is challenging because of the lack of accurate multi-body dynamics models involving joint compliance able of predicting the posture-dependent dynamics of the robot. In this paper, two multi-body dynamics models of articulated industrial robots suitable for machining applications are presented. The link and rotor inertias along with the joint stiffness and damping parameters of the developed models are identified using a combination of multiple-input multiple-output identification approach, computer-aided design model of the robot, and experimental modal analysis. The performance of the developed models in predicting posture-dependent dynamics of a KUKA KR90 R3100 robotic arm is studied experimentally.     

Design Issues for Therapeutic Robot Systems: Results from a Survey of Physiotherapists

Over the years, research into rehabilitation robots has increased considerably. Using robots for rehabilitation can improve persons with physical disabilities to perform the basic activities of daily living. However, rehabilitation robots are not welcome yet in clinical environments. While surveys concerning how patients respond to robots used for rehabilitation have been conducted, no survey exists in the literature concerning how the therapists themselves think of these robotic devices, and what functionality they should possess in order to be effective. This paper presents a survey of physiotherapists concerning their thoughts, experience, and what functionality should be included in robots used for rehabilitation. In particular, the therapists were asked about the development of an intelligent robotic device capable of performing repetitive tasks for patients who suffer from reduced upper and lower limb mobility. In general, the results from this survey suggest that therapists respond positively to the idea of robotic devices in a clinical setting. Furthermore, the majority of respondents are interested in rehabilitation robotics. The results of the survey will be very helpful in the design of robotic systems for use during physiotherapy.     

Accurate dynamic modeling and control parameters design of an industrial hybrid spray-painting robot

To obtain higher performance for hybrid robots subject to nonlinear dynamics and friction, feedforward compensations have been ubiquitously utilized in the industrial robotic field to attenuate these disturbances. However, due to the complex friction model and the coupling and time-varying dynamic of hybrid robots, there is no effective approach to realize accurate feedforward compensations in industrial control systems. This paper investigated an accurate dynamic modeling and control parameters design method to address these issues all at once. Taking the friction of each joint into account, the accurate dynamic model of the hybrid robot is developed and verified by experiments. With the accurate dynamic model, an exact control parameter design method is proposed based on the mapping relationship between the dynamic model and the feedforward compensations. Additionally, the control system designed by the method proposed in this paper is compared with the one tuned by an experienced engineer. Particularly, the robot's position and motion accuracy are also tested by a third-party inspection agency. The experimental and test results show that the position and velocity accuracy of the robot is improved significantly when the control system is designed by using the method proposed in this paper, which proves the effectiveness of the proposed method.     

Merging the autoview image processing language with prolog

A new computer language, called provision, is defined. It combines features of both prolog (for artificial intelligence) and autoview (for image processing). Predicates for image processing, controlling cameras, illumination sources, optics, a video multiplexor and simple robotic devices are all integrated with PROLOG2, an extension of standard core prolog. The result is a powerful medium for expressing a wide range of algorithms for the visual control of robots and advanced industrial inspection. Several provision applications (i.e. ‘programs’) are presented.     

A software engineering approach for the development of heterogeneous robotic applications

One of the most evident characteristics of robotic applications is heterogeneity: large robotic projects involve many different researchers with very different programming needs and areas of research, using a variety of hardware and software that must be integrated efficiently (i.e.: with a low development cost) to construct applications that satisfy not only classic robotic requirements (fault-tolerance, real-time specifications, intensive access to hardware, etc.) but also software engineering aspects (reusability, maintainability, etc.). Most existing solutions to this problem either do not deal with such heterogeneity or do not cover specific robotic needs. In this paper we propose a framework for the integration of heterogeneous robotic software through a software engineering approach: the BABEL development system, which is aimed to cover the main phases of the application lifecycle (design, implementation, testing, and maintainance) when unavoidable heterogeneity conditions are present. The capabilities of our system are shown by its support for designing and implementing diverse real robotic applications that use several programming languages (C, C++, JAVA), execution platforms (RT-operating systems, MS-Windows, no operating system at all), communication middleware (CORBA, TCP/IP, USB), and also a variety of hardware components (Personal Computers, microcontrollers, and a wide diversity of sensor and actuator devices in mobile robots and manipulator arms).     

An imaginary robot model and double-PD control for redundant robotic systems

The theory and applications of an imaginary robot model with a double-PD control law for redundant robotic systems are presented. The imaginary robot model is based on a special Riemannian metric decomposition for general nonlinear dynamic systems. This model offers an effective way for reducing nonlinear feedback formulation while preserving the linearized system equation. The developed procedure is also applicable to redundant robots. A three-dimensional redundant robot main-frame having three revolute joints plus a prismatic joint is used in the paper to illustrate the design procedure based on the imaginary robot model with the double-PD control scheme. The entire dynamic control algorithm is also verified by a simulation study on the four-joint three-dimensional robot arm.     

Dynamic optimization of N‐joint robotic limb deployments

We describe an approach using a stochastic optimization framework (SOF) for operating complex mobile systems with several degrees of freedom (DOFs), such as robotic limbs with N joints, in environments that can contain obstacles. As part of the SOF, we have employed an efficient simulated annealing algorithm normally used in computationally highly expensive optimization and search problems such as the traveling salesman problem and protein design. This algorithm is particularly suited to run onboard industrial robots, robots in telemedicine, remote spacecraft, planetary landers, and rovers, i.e., robotic platforms with limited computational capabilities. The robotic limb deployment optimization approach presented here offers an alternative to time‐intensive robotic arm deployment path planning algorithms in general and in particular for robotic limb systems in which closed‐form solutions do not exist. Application examples for a (N = 4)‐DOF arm on a planetary exploration rover are presented. © 2009 Wiley Periodicals, Inc.     

Merging the autoview image processing language with prolog

A new computer language, called provision, is defined. It combines features of both prolog (for artificial intelligence) and autoview (for image processing). Predicates for image processing, controlling cameras, illumination sources, optics, a video multiplexor and simple robotic devices are all integrated with PROLOG2, an extension of standard core prolog. The result is a powerful medium for expressing a wide range of algorithms for the visual control of robots and advanced industrial inspection. Several provision applications (i.e. ‘programs’) are presented.