用于水下机器人姿态调节的电磁式水下合成射流激励器

目前水下合成射流激励器主要采用机械传动的方式,如凸轮机构,其机械结构复杂且行程不可调.针对此问题,设计了一种机械结构简单且行程可调的电磁式水下合成射流激励器.采用音圈电机带动活塞做直线往复运动来产生合成射流,并对该激励器在不同腔体出口直径、不同活塞振动频率及不同活塞位移条件下开展了一系列推力实验.通过实验得出合成射流平均推力与出口直径呈反比例相关,与活塞振动频率及活塞位移呈正比例相关,且激励器效率随出口直径的增加而增加.结果表明,电磁式水下合成射流激励器能够产生平均推力,是一种新型的水下机器人姿态调节方式.     

基于免疫原理的信号调理系统的故障自愈分析

在机电装备信号调理系统的故障自愈研究中,通过对信号调理系统的结构特点、参数特性及典型故障特征等进行分析,并建立健康因子群,对系统抗衰性能进行评估．在深入分析生物免疫机理的基础上,建立自愈系统与免疫系统映射关系,构建基于免疫原理的故障自愈系统结构模型,并给出模型中主要模块结构和实现算法．根据系统故障自愈模型建立的方法,建立信号调理系统的模型,分析系统的故障,并对此模型进行仿真实验,验证故障自愈系统模型的可行性和有效性．经仿真实验证明,基于免疫原理构建的信号调理故障自愈系统可以实现其主要故障的自愈．     

Design and evaluation of disturbance observer algorithm for cable-driven parallel robots

Recently, a cable-driven parallel robots (CDPRs) has been applied to radio telescope as the accurate actuator, that is the five-hundred-meter aperture spherical telescope. It can be affected by the disturbances such as wind, earthquake and so on. Therefore, this paper developed a disturbance observer (DOB)-based control suitable for CDPR. The propose of the control is to reduce the effects of disturbance while the end-effectors maintains the same position even though the disturbance affects it. The key component of the DOB controller is a disturbance observer, which includes inverse nominal plant for each cable. So, a system identification test was carried out firstly. Then, the simulation and experiment were also carried out to evaluate the performance of the algorithm in CDPR. The results showed that the designed DOB algorithm could effectively reduce disturbances.

     

Expert system to match robots and to synchronize their operations to pick and place large parts

The operation of pick and place large parts is a very common operation on the manufacturing floor. The efficiency of the pick and place operation affects the efficiency of the entire manufacturing floor. Large parts in terms of this research are parts which must be transported by two robots.This paper concludes the development of an expert system and a numerical simulation to assign two available robots to perform the pick and place operations of large parts.The developed expert system consists of a knowledge-base structured in interrelated frames to define large manufacturing systems and an inference-engine to perform the robots matching and their performances monitoring. Matching robots considerations can not be performed by numerical algorithms in real time systems, because they are major computation time consumers. Therefore, unmatched robots can be assigned by the numerical algorithms to perform inefficient pick and place operations. The expert system and the numerical simulation were programmed, and many computer runs were performed to explore the efficiency of the two systems in a large variety of manufacturing systems.The achieved results show that the expert system has no advantage in assigning matched robots to perform the pick and place operations in systems characterized by very short machine process times (0.5 moment to 1 moment). If such short machine process times are relevant, the knowledge-base is updated very frequently, and the inference-engine reasoning processes can not be initiated. For longer machine process times, the frequency of knowledge-base changes is reduced, and the inference-engine reasoning processes can be initiated without delays. Therefore, the advantages of the expert system become significant if machine process times are extended.     

Sliding Mode and PI Controllers for Uncertain Flexible Joint Manipulator

This paper is dealing with the problem of tracking control for uncertain flexible joint manipulator robots driven by brushless direct current motor(BDCM). Flexibility of joint in the manipulator constitutes one of the most important sources of uncertainties. In order to achieve high performance, all parts of the manipulator including actuator have been modeled. To cancel the tracking error, a hysteresis current controller and speed controllers have been developed. To evaluate the effectiveness of speed controllers, a comparative study between proportional integral(PI) and sliding mode controllers has been performed. Finally, simulation results carried out in the Matlab simulink environment demonstrate the high precision of sliding mode controller compared with PI controller in the presence of uncertainties of joint flexibility.     

A high displacement ultrasonic actuator based on a flexural mechanical amplifier

Commonly used high displacement ultrasonic actuators are composed of a Langevin transducer and of a sectional ultrasonic concentrator working as a displacement amplifier. In this work, a novel ultrasonic actuator, which exploits a displacement amplifier vibrating in a flexural mode, is proposed. Design and analysis of the actuator have been performed by using a FEM software. Performances of the proposed actuator have been evaluated by using a classical ultrasonic actuator, based on a stepped horn concentrator, as a benchmark. Simulated results have shown that the flexural amplifier exhibits a displacement amplification about 50% higher than that of the stepped horn; furthermore, due to its capability to absorb a higher electrical power, the whole actuator has shown a maximum displacement that is twice the maximum displacement of the stepped horn actuator. Simulated results have been validated by measurements carried out on two manufactured prototypes.     

Adaptive neuro-fuzzy modeling of a soft finger-like actuator for cyber-physical industrial systems

Soft robotics is a trending area of research that can revolutionize the use of robotics in industry 4.0 and cyber-physical systems including intelligent industrial systems and their interactions with the human. These robots have notable adaptability to objects and can facilitate many tasks in everyday life. One potential use of these robots is in medical applications. Due to the soft body of these robots, they are a suitable replacement for applications like rehabilitation and exoskeletons. In this paper, we present the neuro-fuzzy modeling of a soft pneumatic finger-like actuator. This actuator is a fiber-reinforced soft robot with the shape and dimensions of a real finger and moves in planar motion. A bending sensor is used as a feedback for curvature motion of this actuator. In order to model this actuator, an adaptive neuro-fuzzy inference system is utilized to overcome the hardship in the modeling of the nonlinear performance of the soft materials. An experimental setup is designed to obtain suitable input–output data needed for modeling. The results show the applicability of the utilized method in the modeling of the soft actuator.

     

Synchronized adaptive control for coordinating manipulators with time‐varying actuator constraint and uncertain dynamics

This paper addresses the control issue for cooperative visual servoing manipulators on strongly connected graph with communication delays, in which case that the uncertain robot dynamics and kinematics, uncalibrated camera model, and actuator constraint are simultaneously considered. An adaptive cooperative image‐based approach is established to overcome the control difficulty arising from nonlinear coupling between visual model and robot agents. To estimate the coupled camera‐robot parameters, a novel adaptive strategy is developed and its superiority mainly lies in the containment of both individual image‐space errors and the synchronous errors among networked robots; thus, the cooperative performance is significantly strengthened. Moreover, the proposed cooperative controller with a Nussbaum‐type gain is implemented to both globally stabilize the closed‐loop systems and realize the synchronization control objective under the existence of unknown and time‐varying actuator constraint. Finally, simulations are carried out to validate the developed approach.     

霍夫空间中多足球机器人协作目标定位算法

针对嵌入式仿人足球机器人提出一种霍夫空间中的多机器人协作目标定位算法。机器人利用实验场地中的标志物采用基于三角几何定位方法进行自定位,把机器人多连杆模型进行简化,通过坐标系位姿变换把图像坐标系转换到世界坐标系中,实现机器人目标定位;在多机器人之间建立ZigBee无线传感器网络进行通信,把多个机器人定位的坐标点进行霍夫变换,在霍夫空间中进行最小二乘法线性拟合,获取最优参数,然后融合改进后的粒子滤波实现对目标小球的跟踪;最后在21自由度的仿人足球机器人上进行仿真和实验。数据结果表明,这种多机器人协作的定位算法的精度提高了约48%,在满足实时性的前提下,对目标的跟踪效果也得到了改善。     

Drive based damping for robots with secondary encoders

Robot machining is a growing field due to the combination of large working envelope with relatively low investment and operating costs, compared to milling machine. Besides, the flexibility, which robot serial kinematics bring along, makes application of robot machining possible for different use cases. However, an occurring drawback of robot based machining systems is low stiffness compared to milling machines and, thus, poor accuracy and low eigenfrequencies with few damping. By that, robots for machining are prone to vibrations, resulting in poor machining results. In this paper the authors therefore present an approach for damping these vibrations, using state-of-the-art drives. Secondary encoders, which are increasingly available on industrial robots, are applied to detect these vibrations. This presented strategy has already been proven applicable on feed drives in milling machines and is now applied on industrial robots. To do so, the robot's vibrational behavior, like eigenfrequencies and eigenmodes, is examined in the whole workspace via measurements on real robots. Additionally the excitation by the milling process has been examined in relation to the occurring oscillations at the robot structure. The results of these research is adduced to estimate the applicability of this approach. Based on these results simulations are carried out to test the applicability of the damping strategy on industrial robots. As compliance of robots results mostly from gearboxes, simulation is carried out using a rigid-body-flexible-joint model. The simulations show that the dynamic behavior of the robots axes can be influenced in a positive way and vibration of the robots tool center point can be reduced significantly. Based on these findings, it is planned to implement this method on real hardware to perform tests, develop it further and optimize it.     

计算机网络E1链路接口自愈保护解决方案

根据商用等专用网络存在的问题,提出一种智能网络自愈解决方案,在不改变现有网络结构的情况下,通过在内外网之间加入自行研发的智能网络自愈装置实现网络故障的自愈。该方案设计并实现了对E1链路进行1+1热备份的系统,使E1接入端具备故障的监测、定位和自动处理等功能,系统可在30 s内自动完成自愈处理操作。     

Development of large-scale stacked-type electrostatic actuators for use as artificial muscles

Electrostatic actuators have the advantages of light weight, flexibility, and high energy efficiency, which make them suitable for use as artificial muscles. However, a traditional electrostatic actuator cannot generate long strokes and a high force density at the same time because such actuator would excessively widen the gap between the electrodes because of its structure. This paper presents a newly developed large-scale stacked-type electrostatic actuator (LSEA) intended for use as an artificial muscle for robots. LSEA is a multi-stacked electrostatic actuator that can be linearly contracted by the application of a voltage. It has a unique structure that prevents overextension of the gap between the electrodes. It can therefore generate a large force. The spring characteristics and the relationship between the contractive force and the stroke were experimentally determined. The findings showed that LSEA prevents the overextension of the gap between the electrodes and has a high contraction ratio that is equivalent to that of a mammalian skeletal muscle.     

Adaptive Distributed Fault-tolerant Formation Control for Multi-robot Systems under Partial Loss of Actuator Effectiveness

This paper presents an adaptive distributed fault-tolerant formation control for multi-robot systems. Both the kinematics and dynamics of differential wheeled mobile robots are considered. In particular, the problem caused by actuator faults is investigated. Based on dynamic surface control techniques, adaptive formation controllers can be obtained under a directed communication network. The closed-loop stability is guaranteed by using Lyapunov stability analysis such that all followers can exponentially converge to a leader-follower formation pattern. Simulation and experimental results illustrate that the desired formation pattern can be preserved for a group of wheeled robots subject to unknown uncertainties and actuator faults.     

Deflection of coupled elasticity–electrostatic bimorph PVDF material: theoretical,FEM and experimental verification

Piezoelectric materials have wide applications in the field of mechanical, aerospace and civil engineering because of its voltage dependent actuation. Piezoelectric material goes through voltage generation whenever deflection is induced in it and vice versa. Piezoelectric bimorph beam has been widely used for sensing and actuating. In the actuation mode, an electric field is applied across the beam thickness, one layer contracts while the other expands. This results in the bending of the entire structure and tip deflection. In the sensing mode, the bimorph is used to measure an external load by monitoring the piezoelectric induced electrode voltages. In this research work, a 2D bimorph piezoelectric actuator model having two layers made of polyvinylidene fluoride (PVDF) material was developed to examine the inverse piezoelectric effect. Finite element analysis (FEA) was carried out on specially designed actuator model by using MATLAB Partial Differential Equation (PDE) Toolbox™. Theoretical analysis has been carried out to measure the tip deflection under applied electric field. The laboratory test was performed to investigate the deformation behavior of piezoelectric actuator. It is observed that, more the electric field applied, more the material would be deformed in a particular direction. The experimental results are in good agreement with numerical results.

     

An Intelligent Robust Tracking Control for a Class of Electrically Driven Mobile Robots

This paper addresses the problem of designing robust tracking control for a class of uncertain wheeled mobile robots actuated by brushed direct current motors. This class of electrically‐driven mechanical systems consists of the robot kinematics, the robot dynamics, and the wheel actuator dynamics. Via the backstepping technique, an intelligent robust tracking control scheme that integrates a kinematic controller and an adaptive neural network‐based (or fuzzy‐based) controller is developed such that all of the states and signals of the closed‐loop system are bounded and the tracking error can be made as small as possible. Two adaptive approximation systems are constructed to learn the behaviors of unknown mechanical and electrical dynamics. The effects of both the approximation errors and the unmodeled time‐varying perturbations in the input and virtual‐input weighting matrices are counteracted by suitably tuning the control gains. Consequently, the robust control scheme developed here can be employed to handle a broader class of electrically‐driven wheeled mobile robots in the presence of high‐degree time‐varying uncertainties. Finally, a simulation example is given to demonstrate the effectiveness of the developed control scheme.     

Distributed boundary coverage with a team of networked miniature robots using a robust market-based algorithm

We study distributed boundary coverage of known environments using a team of miniature robots. Distributed boundary coverage is an instance of the multi-robot task-allocation problem and has applications in inspection, cleaning, and painting among others. The proposed algorithm is robust to sensor and actuator noise, failure of individual robots, and communication loss. We use a market-based algorithm with known lower bounds on the performance to allocate the environmental objects of interest among the team of robots. The coverage time for systems subject to sensor and actuator noise is significantly shortended by on-line task re-allocation. The complexity and convergence properties of the algorithm are formally analyzed. The system performance is systematically analyzed at two different microscopic modeling levels, using agent-based, discrete-event and module-based, realistic simulators. Finally, results obtained in simulation are validated using a team of Alice miniature robots involved in a distributed inspection case study.     

A rescue robot system for collecting information designed for ease of use — a proposal of a rescue systems concept

A remote controlled robot for collecting information in disasters, e.g. earthquakes, is one of most effective applications of robots, because it is very dangerous for human beings to locate survivors in collapsed buildings and, in addition, small robots can move into narrow spaces to find survivors. However, previous rescue systems that use robots have a significant problem — a shortage of operators. In catastrophic disasters, in order to save victims, we must explore wide areas within a limited time. Thus, many rescue robots should be employed simultaneously. However, human interfaces of previous rescue robots were complicated, so that well-trained professional operators were needed to operate the robots and, thus, to use many rescue robots, many professional operators were required. However, in such catastrophic disasters it is difficult to get many professional operators together within a short time. In this paper we address the problem and propose a concept of rescue team organization in which professional rescue staff and volunteer staff work together for handling a catastrophic disaster. We point out the necessity for rescue robots which can be operated easily by non-professional volunteer staff. To realize a rescue robot which can be operated easily, we propose a rescue robot system which has a human interface seen in typical, everyday vehicles and a snake-like robot which has mechanical intelligence. We have demonstrated the validity and the effectiveness of the proposed concept by developing a prototype system.     

Programmable springs: Developing actuators with programmable compliance for autonomous robots

Developing real robots that can exploit dynamic interactions with the environment requires the use of actuators whose behaviour can vary from high stiffness to complete compliance or zero impedance. We will outline our design for an electric actuator, called a programmable spring, which can easily be configured using a high-level programming interface to emulate complex multimodal spring damping systems. The types of behaviour that our actuator can exhibit are explored, including antagonistic actuation, cyclic behaviour and hysteresis. This system is intended as the basis for a cost-effective ‘off-the-shelf’ component for robotics research and development.     

CaRINA Intelligent Robotic Car: Architectural design and applications

This paper presents the development of two outdoor intelligent vehicles platforms named CaRINA I and CaRINA II, their system architecture, simulation tools, and control modules. It also describes the development of the intelligent control system modules allowing the mobile robots and vehicles to navigate autonomously in controlled urban environments. Research work has been carried out on tele-operation, driver assistance systems, and autonomous navigation using the vehicles as platforms to experiments and validation. Our robotic platforms include mechanical adaptations and the development of an embedded software architecture. This paper addresses the design, sensing, decision making, and acting infrastructure and several experimental tests that have been carried out to evaluate both platforms and proposed algorithms. The main contributions of this work is the proposed architecture, that is modular and flexible, allowing it to be instantiated into different robotic platforms and applications. The communication and security aspects are also investigated.     

Snake-Like Robot for Rescue Operations — Proposal of a Simple Adaptive Mechanism Designed for Ease of Use

Rescue operations are one of most effective applications for robots and various rescue robots operated by rescue staff have been developed. However, in large-scale disasters, there is a significant problem, i.e., a shortage of operators. In this paper, we consider this problem and propose a snake-like rescue robot which is designed for non-professional volunteer operators. To realize the rescue robot simply, we focus on mechanical design, and realize usability by utilizing properties of its body and the real world. Experiments have been carried out to demonstrate the effectiveness of the proposed robot.