Educational training software for modelling and synthesis of controllers for robotic manipulators and robotized manufacturing cells

A general software system aimed at computer-aided design of controllers for robots and robotized technological systems is described in this paper. The software system includes modules for the synthesis of various levels of robot controller as well as controllers of complex robotized technological systems. The software includes simulation of robotic systems within manufacturing cells using various types of models: complete dynamic models, kinematic models and simple models in the form of finite automata. Using these modelsvarious algorithms for all controls levels in robot controllers may be synthesized taking into account the actual interaction between the robot and its environment. The software system enables the solution of the important problem of the interaction between higher and lower levels of controllers. Finally, a general purpose controller as a target system for the proposed software is described. The controller is designed as an open system allowing the user to apply various control laws and to run in conjunction with an actual robot. The general software system together with the controller represents a powerful educational tool in modern robotics.     

A cable feeder tool for robotized cable winding

Cable winding is an alternative technology to create stator windings in large electrical machines. Today such cable winding is performed manually, which is very repetitive, time-consuming and therefore also expensive. This paper presents the design, function and control system of a developed cable feeder tool for robotized stator cable winding. The presented tool was able to catch a cable inside a cable guiding system and to grab the cable between two wheels. One of these wheels was used to feed cable through the feeder. A control system was integrated in the tool to detect feeding slippage and to supervise the feeding force on the cable. Functions to calculate the cable feed length, to release the cable from the tool and for positional calibration of the stator to be wound were also integrated in the tool. In validating the function of the cable feeder tool, the stator of the linear generator used in the Wave Energy Converter generator developed at Uppsala University was used as an example. Through these experiments, it was shown that the developed robot tool design could be used to achieve automated robotized cable winding. These results also complied with the cycle time assumptions for automated cable winding from earlier research. Hence, it was theoretically indicated that the total winding cycle time for one Uppsala University Wave Energy Converter stator could be reduced from about 80 h for manual winding with four personnel to less than 20 h in a fully developed cable winding robot cell. The same robot tool and winding automation could also be used, with minor adjustments, for other stator designs.     

A modular robot that exhibits amoebic locomotion

This paper discusses a fully decentralized algorithm able to control the morphology of a two-dimensional modular robot called “Slimebot”, consisting of many identical modules, according to the environment encountered. One of the significant features of our approach is that we explicitly exploit “emergent phenomena” stemming from the interplay between control and mechanical systems in order to control the morphology in real time. To this end, we particularly focus on a “functional material” and a “mutual entrainment”, the former of which is used as a spontaneous connectivity control mechanism between the modules, and the latter of which plays as the core of the control mechanism for the generation of locomotion. Simulation results indicate that the proposed algorithm can induce “amoebic locomotion”, which allows us to successfully control the morphology of the modular robot in real time according to the situation without losing the coherence of the entire system. The results obtained are expected to shed light on how control and mechanical systems should be coupled, and what the carefully designed interaction between control and mechanical systems brings to the resulting behavior.     

Flexible real-time mobile robotic architecture based on behavioural models

Behaviour-based models have been widely used to represent mobile robotic systems, which operate in uncertain dynamic environments and combine information from several sensory sources. The specification of complex mobile robotic applications is performed in such models by combining deliberative goal-oriented planning with reactive sensor driven operations. Consequently, the design of mobile robotic architectures requires the combination of time-constrained activities with deliberate time-consuming components. Furthermore, the temporal requirements of the reactive activities are variable and dependent on the environment (i.e. recognition processes) and/or on application parameters (i.e. process frequencies depend on robot speed).In this paper, a real-time mobile robotic architecture to cope with the functional and variable temporal characteristics of behaviour-based mobile robotic applications is proposed. Run-time flexibility is a main feature of the architecture that supports the variability of the temporal characteristics of the workload. The system has to be adapted to the environmental conditions, by adjusting robot control parameters (i.e. speed) or the system load (i.e. computational time), and take actions depending on it. This influence is focused on the ability of the system to select the appropriate activity to be executed depending on the available time, and, to change its behaviour depending on the environmental information. The flexibility of the system is allowed thanks to the definition of a real-time task model and the design of adaptation mechanisms for the regulation of the reactive load.The improvement of the robot quality of service (QoS) is another important aspect discussed in the paper. The architecture incorporates a quality of service manager (QoSM) that allows dynamically monitor analyse and improve the robot performances. Depending on the internal state, on the environment and on the objectives, the robot performance requirements vary (i.e. when the environment is overloaded, global map processes generating high-quality maps are required). The QoSM receives the performance requirements of the robot, and by adjusting the reactive load, the system enables the necessary slack time to schedule the more suitable deliberative processes and hence fulfilling the robot QoS. Moreover, the deliberative load can be scheduled by different heuristic strategies that provide answers of varying quality.     

Velocity anisotropy of an industrial robot

Industrial robots are part of production systems and it is important to place them into the system according to their properties and behaviour. The information, obtained from the technical sheets of robots, about workspace (its dimensions and shape) is insufficient for designing the production system. The information about mobility is missing. To represent the behaviour of the robot in the workspace, velocity anisotropy of the robot is introduced and defined as the length of the shortest velocity ellipsoid axes, which can be constructed for any position of robot in its tool centre point. The position of a tool centre point is equivalent to the point in the workspace. A graphical representation of the 3D workspace with included velocity anisotropy is then performed and an example for a design of a robotised welding production system is given. In this example the benefits of the graphical representation of the workspace with included velocity anisotropy are presented and discussed.     

Path planning of cooperating industrial robots using evolutionary algorithms

In recent years carbon fibre reinforced plastics (CFRP) have gained enormous popularity in aircraft applications. Since the material is very expensive, costs have to be saved through an automated production. For the manufacturing of large structures it is often advisable to use cooperating robots. However, a major problem for the economic use of complex components is the programming of the robot paths. Manual teach-in is no feasible solution and therefore often decides if automated production is profitable. In this work, a system is presented which automatically calculates robot paths using evolutionary algorithms. The use of the proposed system allows, to reduce the commissioning time drastically and changes to the process can be made without great effort by changing the component data.     

Automatic singularity avoidance using joint variations in robottask modification

The research community has addressed the need to improve the flexibility of robot systems. Two particular concepts that have resulted from this research are off-line programming and modular tooling. These concepts are directed at allowing the robot system to be used to perform a variety of tasks with minimal setup time and to allow easy replication of an application. Both of these concepts require that the robot system have the ability to measure the position and orientation of features in the workspace. These measurements can then be used to perform coordinate transformations on each of the task data points. These modified task data points then, theoretically, facilitate the performance of the task by the robot system without human intervention     

Development of minimalist bipedal walking robot with flexible ankle and split-mass balancing systems

This paper presents a novel design of minimalist bipedal walking robot with flexible ankle and split-mass balancing systems.The proposed approach implements a novel strategy to achieve stable bipedal walk by decoupling the walking motion control from the sideway balancing control.This strategy allows the walking controller to execute the walking task independently while the sideway balancing controller continuously maintains the balance of the robot.The hip-mass carry approach and selected stages of walk implemented in the control strategy can minimize the efect of major hip mass of the robot on the stability of its walk.In addition,the developed smooth joint trajectory planning eliminates the impacts of feet during the landing.In this paper,the new design of mechanism for locomotion systems and balancing systems are introduced.An additional degree of freedom introduced at the ankle joint increases the sensitivity of the system and response time to the sideway disturbances.The efectiveness of the proposed strategy is experimentally tested on a bipedal robot prototype.The experimental results provide evidence that the proposed strategy is feasible and advantageous.     

Architecting centralized coordination of soccer robots based on principle solution

Coordination strategy is a relevant topic in multi-robot systems, and robot soccer offers a suitable domain to conduct research in multi-robot coordination. Team strategy collects and uses environmental information to derive optimal team reactions, through cooperation among individual soccer robots. This paper presents a diagrammatic approach to architecting the coordination strategy of robot soccer teams by means of a principle solution. The proposed model focuses on robot soccer leagues that possess a central decision-making system, involving the dynamic selection of the roles and behaviors of the robot soccer players. The work sets out from the conceptual design phase, facilitating cross-domain development efforts, where different layers must be interconnected and coordinated to perform multiple tasks. The principle solution allows for intuitive design and the modeling of team strategies in a highly complex robot soccer environment with changing game conditions. Furthermore, such an approach enables systematic realization of collaborative behaviors among the teammates.     

Motion coordination and reactive control of autonomous multi-manipulator systems

The emerging field of service robots demands new systems with increased flexibility. The flexibility of a robot system can be increased in many different ways. Mobile manipulation—the coordinated use of manipulation capabilities and mobility—is an approach to increase robots flexibility with regard to their motion capabilities. Most mobile manipulators that are currently under development use a single arm on a mobile platform. The use of a two-arm manipulator system allows increased manipulation capabilities, especially when large, heavy, or non-rigid objects must be manipulated. This article is concerned with motion control for mobile two-arm systems. These systems require new schemes for motion coordination and control. A coordination scheme called transparent coordination is presented that allows for an arbitrary number of manipulators on a mobile platform. Furthermore, a reactive control scheme is proposed to enable the platform to support sensor-guided manipulator motion. Finally, this article introduces a collision avoidance scheme for mobile two-arm robots. This scheme surveys the vehicle motion to avoid platform collisions and arm collisions caused by self-motion of the robot. © 1996 John Wiley & Sons, Inc.     

Adaptive robot training by programming and guiding

The simplest and most common robot training method is operator-guiding, but this method is inflexible and limited to fixed sequences. Explicit textual robot programming has enjoyed many advances in the last decade and current research implementations are powerful. But explicit programming is complex and programmers must be specially trained. Mixed systems attempt to unite the facility of guiding with the power of programming. However, existing mixed systems exhibit mismatches in the interaction between programming and guiding, because they ignore underlying dependencies between the programmer and operator. An operator may (1) be given insufficient visual cues; (2) lack the required dexterity; or (3) be required to add unforeseen movement sequences to the program. This paper presents the design and implementation of ART (adaptive robot trainer), a prototypical mixed robot training system that eliminates or corrects deficiencies in visual cues and dexterity, and additionally improves the guiding and programming components. Mixed systems and assembly tasks are analysed, to give an effective representation of task state, which in turn motivates the design of ART's language to automate much of the program-guiding interaction. The language allows the programmer to express assembly operations and object-feature relationships in a natural way while providing the system with the information necessary to maintain the task state. The representation also enables the correction of guiding errors, flexibility in the guiding protocol and the generation of meaningful messages to prompt operator actions. These principles in the design and implementation pave the road to more instructable, capable robots.Now at Bell Northern Research, Ottawa.     

Analysis of active vibration control of multi-degree-of-freedom flexible systems by Newmark method

A flexible robot arm can be modeled as a lumped-parameter multi-degree-of-freedom mass–spring system. The actuator at one end positions the payload at the other end. The flexibility causes the vibration of the payload at the end point. This paper considers a 4-degree-of-freedom mass–spring system. A closed loop active vibration control system is analyzed to suppress the end-point vibrations. The mathematical model of the system is established by using the Lagrange equations. The average of the displacements of the masses is used for the feedback. A PID control is applied. The numerical solution is obtained by integrating the control action into the Newmark method. The instantaneous average displacement is subtracted from the reference input to find the error signal value at a time step in the Newmark solution. The PID control action is applied to find the actuator signal value in the time step. This input value is used to find the displacements for the subsequent time step. The process is continued until the steady-state value is approximately reached. The analytical solution is given by using the Laplace transform method to check the validity of the Newmark solution. It is observed that the numerical and analytical results are in good agreement. The integration of the control action into Newmark solution as presented in this study can be extended to finite element solutions to simulate the control of complex mechanical systems.     

A support-design framework for Cooperative Robots systems in labor-intensive manufacturing processes

Manufacturing processes and industrial systems gradually change their traditional layouts and configurations, preparing to introduce novel integrated human-robot technologies as collaborative robots and exoskeletons. Whether mass customization of lot size and the production mix discourages the adoption of capital-intensive automation, collaborative robots become affordable and effective and a hotspot of the debate on manufacturing systems. This paper provides a novel support-design framework for the cooperative robot system in labor-intensive manufacturing processes to aid layout and task scheduling design. Through an iterative closed-loop methodology, this framework explores the impact of a cooperative robot in a labour-intensive manufacturing system like the production facility of a food service company. The framework leads the designer through the re-layout of the end-of-line, the economic and technical feasibility analyses, using simulation to estimate payback and ergonomics benefits for workers. Within the proposed layout, we state that adopting a cooperative cobot for the end-of-line is affordable and ergonomically convenient without representing a safety threat for workers. The testbed confirms the framework as an enabling tool for human-robot technologies integration in current manufacturing systems under budget and workers-driven constraints.     

RosLaunch文件的可视化创建方法设计与实现

机器人软件开发不仅涉及到机器人硬件架构还有相关的机器人软件架构,这要求开发人员具备很好的知识储备。ROS(Robot Operating System)系统中通常使用RosLaunch文件一次启动多个节点(Node)完成指定任务,对于非专业的人员来说,设置启动文件十分困难。可视化开发能够让开发人员以图形的方式编辑和设计程序的功能和格式,不必再对着代码修改。这种方式更加直观,能很好的降低出错误几率。本文设计了一种可视化RosLaunch文件创建工具,能够有助于创建机器人启动文件,并将已有启动文件映射成图形直观展示出来。在验证实验中创建了Kinova jaco机械臂的完整启动文件,放在其工作空间下可以正常启动机器人。本文中的方法可以大大降低机器人开发难度和门槛,不熟练的开发人员也可以使用此软件对机器人进行简单的调试和开发,从而节省了机器人开发人员培养的成本,提高了开发效率。     

KBase: A customizable tool for building DBase-compatible knowledge-based systems

KBase is a customizable development tool for building knowledge-based systems that are compatible with DBase III tables. Currently, most tools for developing knowledge-based systems do not integrate well with databases. DBase III is the most common database system used in the personal computer environment. KBase is built such that all DBase III commands and functions are supported. Furthermore, customizing and extending KBase is as easy as programming in DBase. This flexibility arises because KBase is built using the “C” programming language and Clipper, a DBase compiler. Using Clipper also allows KBase to use many functions in the Clipper library. In this paper, we describe how KBase's design is conceived. At the end, we also give a brief tour of the program with an implemented example to illustrate its application.     

Investigations on increasing flexibility of hardware and software of industrial robots

The high flexibility of an industrial robot results from its free programmable control and high moveability. Still, there are some cases of application that demand more flexibility of hardware and software. If a case of application is found that requires more control functions than the standard control offers to the user, a lot of time and work is necessary to implement new control software to the existing control program. This is possible in an easy and quick way if the control program is written in a higher programming language. Also the programming of new robot controls becomes easy, quick and transparent. Other problems are found in the adaption of end effectors to the handling task. One solution is automatic changing of end effectors. Another solution is construction of universal end effectors, like versatile grippers. Both possibilities have their own range of application and must be chosen under the requirements of the special application case.     

Development of CAM system based on industrial robotic servo controller without using robot language

This paper describes the development of a robotic CAM system for an articulated industrial robot RV1A from the view point of robotic servo controller. It is defined here that the CAM system includes an important function which allows an industrial robot to move along cutter location data (CL data) consisting of position and orientation components. In addition, the developed CAM system has a high applicability to other industrial robots whose servo systems are technically opened to end-users. The developed robotic CAM system works as a straightforward interface between a general CAD/CAM and an industrial robot. At the present stage, the relationship between CAD/CAM and industrial robots is not well established compared to NC machine tools that are widely spread in manufacturing industries. The CAM systems for NC machine tools are already established, however, the CAM system for industrial robots has not been sufficiently considered and developed yet. A teaching pendant is generally used to obtain position and orientation data of the arm tip before an industrial robot works. Here, in order to enhance the relationship between a conventional CAD/CAM system and an industrial robot, a simple and straightforward CAM system without using any robot language is developed and implemented. The basic design of the robotic CAM system and the experimental results are presented in this paper.     

Flexible system for simulating and tele‐operating robots through the internet

Simulation and teleoperation tools offer many advantages for the training or learning of technological subjects, such as flexibility in time‐tables and student access to expensive and limited equipment. In this paper, we present a new system for simulating and tele‐operating robot arms through the Internet, which allows many users to simulate and test positioning commands for a robot by means of a virtual environment, as well as execute the validated commands in a real remote robot of the same characteristics. The main feature of the system is its flexibility in managing different robots or including new robot models and equipment. © 2005 Wiley Periodicals, Inc.     

移动机器人的可重构控制系统

针对未知环境下如何提高移动机器人导航控制系统的柔性和鲁棒性,分析了复杂控制系统（Complex Control System）的体系结构,以异构多Agent系统理论为基础,提出了一种可在多个层次上动态重构的控制系统设计方案,有效地增强了移动机器人的适应能力,为实现控制系统跟随任务和环境变化而动态配置提供了一条可行的途径。设计方案在移动机器人MORCS-I上得到了初步的技术验证,部分实验数据展示了重构控制的实际效果,所具有的通用性表明其亦适合应用于其他类型的复杂控制系统。     

Tracking in nonlinear differential-algebraic control systems with applications to constrained robot systems

We consider the design of a feedback control law for control systems described by a class of nonlinear differential-algebraic equations so that certain desired outputs track given reference inputs. The nonlinear differential-algebraic control system being considered is not in state variable form. Assumptions are introduced and a procedure is developed such that an equivalent state realization of the control system described by nonlinear differential-algebraic equations is expressed in a familiar normal form. A nonlinear feedback control law is then proposed which ensures, under appropriate assumptions, that the tracking error in the closed loop differential-algebraic system approaches zero exponentially. Applications to simultaneous contact force and position tracking in constrained robot systems with rigid joints, constrained robot systems with joint flexibility, and constrained robot systems with significant actuator dynamics are discussed.