The kinematics modeling based on Spinor theory for CT-guided hybrid robot

This paper focused on a simplified method for solving the hybrid robot kinematics in CT-guided(computerized tomography,CT)surgery.By position constraint introduced,the hybrid robot can betransformed as a redundant serial 7-DOF robot.The forward displacement calculation was developedbased on the product-of-exponential formula(POE).Because of the kinematics complexity of the hybridand redundant robot,the combination technique of Ulrich two-step iteration method and paul variablesdetachment method(UTT-PVD)was introduced to fulfill the inverse kinematics of redundant robot,thenovelty of which lay in the flexibility of various robots structures and in high calculation efficiency for real-time control.The process of solving the inverse displacement was analyzed.The UTI-PVD method can beapplicable to kinematics of many robots,especially for redundant robots with more than 6D0F.The kine-matics simulation was provided,and robot dexterity analysis was presented.The results indicated that thehybrid robot could implement the minimally invasive CT-guided surgery.

Dynamics of 3-DOF Hybrid Robot Manipulator

This paper introduces a 3-dof hybrid robotic manipulator which is constructed by combining a parallel mechanism and a pantograph to increase stiffness as well as workspace. And by analyzing its kinematics and dynamics with Lagrange’s method, the dynamic model is obtained which is essential for feed-forward control of the manipulator. An explicit solution is given out. Finally, a simulation test is carried out on computers.

An iterative learning method for realizing accurate dynamic feedforward control of an industrial hybrid robot

Feedforward control based on an accurate dynamic model is an effective approach to reduce the dynamic effect of the robot and improve its performance. However, due to the complicated work environment with considerable uncertainty, it is difficult to obtain a high-precision dynamic model of the robot, which severely deteriorates the achievable control performance. This paper proposes an iterative learning method to accurately design the industrial feedforward controller and compensate for the external uncertain dynamic load of the robot. Based on a standard dynamic model, a complete linear feedforward controller is presented.An iterative design strategy is given to iteratively update the feedforward controller by combining the Moore-Penrose Inverse and the PID learning rate. Experiments are carried out on a 5-DOF industrial hybrid robot to validate the effectiveness of the proposed iterative learning method. The experiment results illustrate that the industrial feedforward controller can rapidly converge to the optimal controller and significantly improve the servo performance by using the proposed method. This paper provides an effective method for applying iterative learning control to an unopened industrial control system. It is very useful for the practical control of hybrid robots in industrial field.

A Closed-Loop Dynamic Controller for Active Vibration Isolation Working on A Parallel Wheel-Legged Robot

Serving the Stewart mechanism as a wheel-legged structure,the most outstanding superiority of the proposed wheel-legged hybrid robot(WLHR)is the active vibration isolation function during rolling on rugged terrain.However,it is difficult to obtain its precise dynamic model,because of the nonlinearity and uncertainty of the heavy robot.This paper presents a dynamic control framework with a decentralized structure for single wheel-leg,position tracking based on model predictive control(MPC)and adaptive impedance module from inside to outside.Through the Newton-Euler dynamic model of the Stewart mechanism,the controller first creates a predictive model by combining Newton-Raphson iteration of forward kinematic and inverse kinematic calculation of Stewart.The actuating force naturally enables each strut to stretch and retract,thereby realizing six degrees-of-freedom(6-DOFs)position-tracking for Stewart wheel-leg.The adaptive impedance control in the outermost loop adjusts environmental impedance parameters by current position and force feedback of wheel-leg along Z-axis.This adjustment allows the robot to adequately control the desired support force tracking,isolating the robot body from vibration that is generated from unknown terrain.The availability of the proposed control methodology on a physical prototype is demonstrated by tracking a Bezier curve and active vibration isolation while the robot is rolling on decelerate strips.By comparing the proportional and integral(PI)and constant impedance controllers,better performance of the proposed algorithm was operated and evaluated through displacement and force sensors internally-installed in each cylinder,as well as an inertial measurement unit(IMU)mounted on the robot body.The proposed algorithm structure significantly enhances the control accuracy and vibration isolation capacity of parallel wheel-legged robot.

Analysis on the crossing obstacle of wheel-track hybrid mobile robot

A novel wheel-track hybrid mobile robot with many movement patterns is designed.According to different environments,it can switch between the pure wheel pattern and the pure track one.According to a homogeneous coordinate transformation matrix,gravity stability and its obstacle performance are analyzed.Its gravity equation and climbing obstacle conditions are established.Experimental results show that this hybrid mobile robot could fully possess the advantages of both the wheel and the track mechanisms and achieve a good obstacle climbing capability.

A Study on Development of a Hybrid Aerial/Terrestrial Robot System for Avoiding Ground Obstacles by Flight

To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various terrestrial robots, such as snake-like, humanoid, spider-type, and wheeled units. Another area of active research in recent years has been aerial robots with small helicopters for operation indoors and outdoors. However,less research has been performed on robots that operate both on the ground and in the air. Accordingly, in this paper, we propose a hybrid aerial/terrestrial robot system. The proposed robot system was developed by equipping a quadcopter with a mechanism for ground movement. It does not use power dedicated to ground movement, and instead uses the flight mechanism of the quadcopter to achieve ground movement as well. Furthermore, we addressed the issue of obstacle avoidance as part of studies on autonomous control. Thus, we found that autonomous control of ground movement and flight was possible for the hybrid aerial/terrestrial robot system, as was autonomous obstacle avoidance by flight when an obstacle appeared during ground movement.

基于改进Hybrid A^(*)算法的阿克曼移动机器人路径规划

针对移动机器人路径规划的效率和所规划路径的安全性问题,基于阿克曼六轮转向模型,提出了一种基于改进Hybrid A^(*)算法的路径规划方法。通过改进Hybrid A^(*)算法中的启发式函数,引入距离惩罚函数,减少了节点搜索数量;通过构建安全走廊,引导移动机器人尽可能远离障碍物;在代价函数中加入了节点向前、换向和向后扩展的惩罚项,确保所规划路径的可执行性与安全性。通过仿真表明,基于改进Hybrid A^(*)算法的路径规划方法适用于阿克曼六轮移动机器人,提高了路径规划的效率,规划的路径更具安全保障。

Hybrid force control of astronaut rehabilitative training robot under active loading mode

In order to mitigate the effects of space adaptation syndrome(SAS) and improve the training efficiency of the astronauts, a novel astronaut rehabilitative training robot(ART) was proposed. ART can help the astronauts to carry out the bench press training in the microgravity environment. Firstly, a dynamic model of cable driven unit(CDU) was established whose accuracy was verified through the model identification. Secondly, to improve the accuracy and the speed of the active loading, an active loading hybrid force controller was proposed on the basis of the dynamic model of the CDU. Finally, the actual effect of the hybrid force controller was tested by simulations and experiments. The results suggest that the hybrid force controller can significantly improve the precision and the dynamic performance of the active loading with the maximum phase lag of the active loading being 9° and the maximum amplitude error being 2% at the frequency range of 10 Hz. The controller can meet the design requirements.

Docking process on hybrid self-reconfigurable modular robots

A novel hybrid self-reconfigurable modular robot is designed to finish the morphing action from line shape to hexagon shape. The robot is composed of many basic modules,each of which consists of a master module and a slave module in the shape of triangular prism. There are four connection ports on each basic module. For the master module there are two holes on each connection port,and for the slave one there are two pegs on each connection. The docking process between two neighboring basic modules is analyzed with a peg-in-hole mechanical structure. A small motion's method is presented and the contact forces are derived. According to the force/moment,the pose of a motion module should be adjusted to make two neighboring modules align and finish the docking process.Finally,a simulation of 3 basic modules is shown to finish the morphing and docking process effectively. The system can finish the morphing task from the line shape to the hexagon shape.

Robot Positioning and Navigation Based on Hybrid Wireless Sensor Network

Traditional sensor network and robot navigation are based on the map of detecting the fields available in advance.The optimal algorithms are developed to solve the energy saving,the shortest path problems,etc.However,in the practical environment,there are many fields,whose map is difficult to get,and needs to be detected.In this paper a kind of ad-hoc navigation algorithm is explored,which is based on the hybrid sensor network without the prior map in advance.The navigation system is composed of static nodes and dynamic nodes.The static nodes monitor the occurrances of the events and broadcast them.In the system,a kind of algorithm is to locate the robot,which is based on cluster broadcasting.The dynamic nodes detect the adversary or dangerous fields and broadcast warning messages.The robot gets the message and follows ad-hoc routine to arrive where the events occur.In the whole process,energy saving has been taken into account.The algorithms,which are based on the hybrid sensor network,are given in this paper.The simulation and practical results are also available.

A Sensing and Robot Navigation of Hybrid Sensor Network

Traditional sensor network and robot navigation are based on the map of detecting fields available in advance. The optimal algorithms are explored to solve the energy saving, shortest path problems, etc. However, in practical environment, there are many fields, whose map is difficult to get, and need to detect. This paper explores a kind of ad-hoc navigation algorithm based on the hybrid sensor network without the prior map. The system of navigation is composed of static nodes and mobile nodes. The static nodes monitor events occurring and broadcast. In the system, a kind of cluster broadcast method is adopted to determine the robot localization. The mobile nodes detect the adversary or dangerous fields and broadcast warning message. Robot gets the message and follows ad-hoc routine to arrive the events occurring place. In the whole process, energy saving has taken into account. The algorithms of nodes and robot are given in this paper. The simulate and practical results are available as well.

Design of Underwater Robot Lines Based on a Hybrid Automatic Optimization Strategy

在这份报纸，混合自动优化策略为设计被建议在水下机器人线。Isight 作为一个集成平台被介绍。这个平台的构造包括 UG6.0， GAMBIT2.4.6 和 FLUENT12.0 基于用户编程和几个商业软件。一个聪明的参数优化方法，粒子群优化，被合并到平台。为了验证策略，求婚了，模拟被进行在上在水下机器人为 5470 建模，它从 DTRC SUBOFF 工程发源。与自动优化平台，最小的抵抗作为优化目标被拿；是的湿表面区域限制条件；象设计变量的船身前半部，最大的身体半径和船体后部最小半径的长度。随 CFD 计算， RANS 方程和标准骚乱模型被用于直接数字的模拟。由模拟结果的分析，平台效率高，这被结束。通过平台，为线的设计的许多计划被产生，最佳的解决方案被完成。聪明的优化算法和数字模拟的联合保证一个全球最佳的答案并且改进寻找的答案的效率。

Collision avoidance for a mobile robot based on radial basis function hybrid force control technique

Collision avoidance is always difficult in the planning path for a mobile robot. In this paper, the virtual force field between a mobile robot and an obstacle is formed and regulated to maintain a desired distance by hybrid force control algorithm. Since uncertainties from robot dynamics and obstacle degrade the performance of a collision avoidance task, intelligent control is used to compensate for the uncertainties. A radial basis function （RBF） neural network is used to regulate the force field of an accurate distance between a robot and an obstacle in this paper and then simulation studies are conducted to confirm that the proposed algorithm is effective.

Motion design of a hybrid wheeled/legged robot for lunar exploration

The robot consists of a quadruped mechanism and two active dual-wheel casters possesses the advan-tages of wheeled and legged mechanism, and can quickly move on the relatively plane ground with the wheeledmechanism, and can walk on the extremely uneven terrain with the legged mechanism. The effectiveness of themotion design of the hybrid robot is illustrated by simulation results.

Hybrid Visual Servoing Control for Robotic Arc Welding Based on Structured Light Vision

A novel hybrid visual servoing control method based on structured light vision is pro-posed for robotic arc welding with a general six degrees of freedom robot. It consists of a positioncontrol inner-loop in Cartesian space and two outer-loops. One is position-based visual control inCartesian space for moving in the direction of weld seam, i.e., weld seam tracking, another is image-based visual control in image space for adjustment to eliminate the errors in the process of tracking.A new Jacobian matrix from image space of the feature point on structured light stripe to Cartesianspace is provided for dierential movement of the end-e?ector. The control system model is simplifiedand its stability is discussed. An experiment of arc welding protected by gas CO2 for verifying iswell conducted.

基于双混联机器人协同运动控制的薄壁件镜像铣削研究

为提高薄壁件镜像铣削过程中的加工质量,本文提出一种针对双混联机器人镜像铣削的协同运动控制策略。首先,结合机器人运动控制特点,研发出一种双CPU主从控制架构的开放式数控系统,以实现人机交互和运动控制;然后,为实现双机协同运动并提高薄壁件加工质量,在数控系统中集成了4大关键技术,分别是双机器人的镜像路径生成、同步速度规划、协同运动学和运动误差实时补偿;最后,基于自主开发的集成式镜像铣削数控系统,开展了单点和多点支撑、双机协同与非协同加工的平面薄壁件槽铣削试验,多点支撑的平面铣削试验,大曲率路径高速协同运动试验与曲面薄壁件槽铣削加工试验。试验结果表明,提出的协同运动控制策略能够保证双机器人具有较高的同步位置精度。此外,多点支撑方式在保证薄壁件铣削壁厚的同时,还可提高工件铣削的颤振稳定性。

基于改进HybridA^(*)的非完整约束机器人路径规划算法研究

为了实现单舵轮AGV在物流场景下的精准自主导航,针对基于HybridA*算法搜索的路径容易贴近障碍物的缺陷和算法在路径平滑后可能与障碍物冲突的问题,本文提出一种基于改进HybridA*的非完整约束轮式移动机器人路径规划方法。对于路径搜索部分,将距离场地图引入启发式函数,以提高搜索效率,并保持搜索路径远离障碍物;对于路径平滑部分,将优化问题转化为二次规划问题,通过边界约束保证避障效果。在ROS平台上仿真实验的结果表明,该路径规划方法可有效用于非完整约束系统,为单舵轮AGV自主导航的准确运动奠定了路径智能规划的基础。

香蕉采摘与吊运作业机器人运动与动力性能分析

由于香蕉果串的结果高度和果形尺寸较大,且采摘过程极易发生损伤,给其采摘带来极高难度,目前仍停留在比较落后的人工采摘方式上,劳动强度大。为此,提出了一种香蕉采摘与吊运作业机器人,可将香蕉果柄的切割、夹持和香蕉果串的吊放作业整体性完成,其机械系统主要由伺服连杆机械臂、夹持与切割末端执行器和液压履带行走动力单元等部分组成。工作时,末端执行器夹持与切割香蕉果柄的直径范围为40~150mm,液压履带车行走的最大行走速度为1.07m/s。通过基于ADAMS的机械系统运动和动力学仿真分析获得了伺服连杆机械臂的作业范围,以香蕉按照宽窄行宜机化种植模式为基础,对接近实际情况的伺服驱动作业流程进行了仿真研究,验证了各伺服电机的驱动能力。

Compliant landing of a trotting quadruped robot based on hybrid motion/force robust control

A compliant landing strategy for a trotting quadruped robot on unknown rough terrains based on contact force control is presented. Firstly, in order to lower the disturbance caused by the landing impact force, a landing phase is added between the swing phase and the stance phase, where the desired contact force is set as a small positive constant. Secondly, the joint torque optimization of the stance legs is formulated as a quadratic programming(QP) problem subject to equality and inequality/bound constraints. And a primal-dual dynamical system solver based on linear variational inequalities(LVI) is applied to solve this QP problem. Furthermore, based on the optimization results, a hybrid motion/force robust controller is designed to realize the tracking of the contact force, while the constraints of the stance feet landing angles are fulfilled simultaneously. Finally, the experiments are performed to validate the proposed methods.

对称悬架混联轮腿机器人结构设计与参数优化

为了实现机器人在地下空间低能耗的灵活运动,文中设计了一种对称悬架混联轮腿机器人,并针对其腿部参数优化问题,提出了一种基于沙猫群算法的性能均衡优化方法(简称均衡优化方法)。结合对称四边形机构与悬架系统,设计了一种对称悬架混联式轮腿结构,并建立其运动学和动力学模型,分析了腿部杆长对单轮腿运动空间和灵活性指标的影响,预优化确定了腿部初始杆长均为0.3 m。在满足轮腿越障规划空间及高灵活性的基础上,为了实现低能耗,建立了轮腿性能均衡优化评价指标,采用均衡优化方法对腿部杆长进行了优化研究。数值计算结果表明:大腿和小腿杆长最优值分别为0.23 m和0.3 m,该轮腿运动能耗为23.18 J,运动空间为0.1322 m2,灵活性指标变化范围为(0.2,1)。优化后灵活性保持不变,运动空间减小了24.54%,能耗降低了22.60%,验证了该方法合理有效,为轮腿机器人的设计与优化提供了一种新的思路。