An active hybrid parallel robot for minimally invasive surgery

During the last years, there has been an increase in research in the field of medical robots. This trend motivated the development of a new robotics field called “robotic-assisted minimally invasive surgery”. The paper presents the kinematic and dynamic behavior of a parallel hybrid surgical robot PARASURG-9M. The robot consists of two subsystems: a surgical robotic arm, PARASURG 5M with five motors, and an active robotized surgical instrument PARASIM with four motors. The methodology for the robot kinematics is presented and the algorithm for robot workspace generation is described. PARASURG-9M inverse dynamic simulation is performed using MSC Adams and finally some numerical and simulation results of the developed experimental model with its system control are also described.     

Kinematics and workspace modeling of a new hybrid robot used in minimally invasive surgery

The geometric and kinematic models of a new surgical hybrid robot used for camera and active instruments positioning are presented in this paper. The robot workspace is computed and illustrated following the singularities analysis. The robot structure consists of two modules: the PARAMIS robot, and the new serial positioning module. The serial positioning module is used to obtain a mechanically fixed remote center of motion (RCM), enabling the structure to manipulate also active instruments. The new robot provides the necessary motion control to respect the particularities and restrictions of surgical applications. The detailed workspace analysis demonstrates the importance of the relative positioning between the robot and the patient. A constructive solution of the new serial module, the numerical results and conclusions from the performed simulations are described.     

脊柱微创手术机器人运动控制系统的设计

设计了一套医疗机器人系统用于辅助脊柱微创外科手术操作。详细论述了这款5自由度脊柱微创手术导航机器人运动控制系统的设计与实现。提出了具有创新性的步进电机细分驱动模式,将电机定子电流从方波形状转变成为了正弦波形状,消除了步进电机的步间振荡现象。利用传感机构实现了对机器人末端工具的位姿反馈,并以此构成了对机器人末端工具的闭环控制。通过CAN实现了数字信号处理器之间的网络互联。最后对该系统进行实验,结果验证了控制系统具有良好的可靠性和稳定性。     

具有震颤抑制的微创机器人主从控制系统设计

详述了一种用于抑制微创手术机器人震颤现象的主从控制系统，提出了针对人手生理震颤的新型零相位滤波方法及针对从操作臂关节“粘滑行为”的前馈补偿PD伺服算法。新型零相位滤波避免了传统低通滤波器容易造成延时和传统零相位滤波无法在线使用的缺点，前馈补偿PD伺服算法通过摩擦补偿克服了非线性摩擦对从操作臂运动造成的影响。最后，对系统进行仿真及实验，结果表明该方法能有效地抑制机器人手术工具末端的震颤现象。     

Kinematic analysis of a new 5-DOF modular parallel robot for brachytherapy

Cancer represents one of the main causes of the death. Huge efforts have been made by the scientific community to provide better cancer treatment solutions. An innovative option is the brachytherapy (BT), a local radiation technique for cancer treatment, which enables the delivery of high doses of radiation inside the tumors. BT usage is limited by the insufficient accuracy of the radioactive seeds placement. In order to eliminate these limitations, the authors propose an innovative modular structure which would enable the precise positioning of the BT needles in any part of the patient body. The paper presents the kinematic modeling of the new 5-DOF robotic structure. The workspace analysis and the singularities are studied and the dexterous workspace for a given insertion point inside the patient is also shown. Finally, some numerical simulations of different BT needle trajectories are included.     

A robust adaptive control of a parallel robot

The work presented in this article deals with the robust adaptive control tracking of a 6 degree of freedom parallel robot, called C5 parallel robot. The proposed approach is based on the coupling of sliding modes and multi-layers perceptron neural networks (MLP-NNs). It does not require the inverse dynamic model for deriving the control law. The MLP-NN is added in the control scheme to estimate the gravitational and frictional forces along with the non-modelled dynamic effects. The nonlinearity problem, present in neural networks, is resolved using Taylor series expansion. The proposed approach allows to adjust the parameters of neural network and sliding mode control terms by taking into account a reference model and the closed-loop stability in the Lyapunov sense. We implemented our approach on the C5 parallel robot of LISSI laboratory and performed experiments to observe its effectiveness and the robust behaviour of the controller against external disturbances.     

Position tracking of a 3-PSP parallel robot using dynamic growing interval type-2 fuzzy neural control

Parallel robots have complicated structures as well as complex dynamic and kinematic equations, rendering model-based control approaches as ineffective due to their high computational cost and low accuracy. Here, we propose a model-free dynamic-growing control architecture for parallel robots that combines the merits of self-organizing systems with those of interval type-2 fuzzy neural systems. The proposed approach is then applied experimentally to position control of a 3-PSP (Prismatic–Spherical–Prismatic) parallel robot. The proposed rule-base construction is different from most conventional self-organizing approaches by omitting the node pruning process while adding nodes more conservatively. This helps preserve valuable historical rules for when they are needed. The use of interval type-2 fuzzy logic structure also better enables coping with uncertainties in parameters, dynamics of the robot model and uncertainties in rule space. Finally, the adaptation structure allows learning and further adapts the rule base to changing environment. Multiple simulation and experimental studies confirm that the proposed approach leads to fewer rules, lower computational cost and higher accuracy when compared with two competing type-1 and type-2 fuzzy neural controllers.     

基于D-H法的农业采摘机器人运动协作控制系统设计

为提升农业采摘机器人运动协作控制性能,降低机器人碰撞概率,利用D-H法优化设计机器人运动协作控制系统。改装位置、力矩以及碰撞传感器设备,优化运动协作控制器与驱动器,调整系统通信模块结构,完成硬件系统的优化。利用D-H法构建农业采摘机器人数学模型,在该模型下,利用传感器设备实现机器人实时位姿的量化描述,通过机器人采摘流程的模拟,分配机器人运动协作任务,从位置和姿态等多个方面,确定运动协作控制目标,经过受力分析求解机器人实际作用力,最终通过控制量的计算,实现农业采摘机器人的运动协作控制功能。通过系统测试实验得出结论：与传统控制系统相比,机器人位置、姿态角和作用力的控制误差分别降低了约40mm、0.2°和1.2N,在优化设计系统控制下,机器人的碰撞次数得到明显降低。     

基于PLC技术的焊接机器人主从协调运动控制系统研究

焊接机器人运动控制系统的控制功能直接决定了焊接工作质量,利用PLC技术优化设计焊接机器人主从协调运动控制系统。在系统硬件设计方面,装设位置、速度、旋转电弧等传感器设备,利用传感数据检测焊接机器人实时位姿。在考虑焊接机器人组成结构、工作原理以及动力驱动方式的情况下,构建焊接机器人的数学模型。结合当前位姿和控制目标之间的位置关系,规划焊接机器人主从协调运动轨迹,在约束条件的作用下,利用PLC控制器生成控制指令,作用在改装的焊接机器人驱动器上,实现系统的焊接机器人主从协调运动控制功能。通过系统测试实验得出结论：与传统控制系统相比,优化设计系统的速度控制误差、姿态角控制误差分别降低了0.075mm/s和0.38°,在优化系统控制下,主从焊接机器人的运动轨迹与规划轨迹之间无明显差异。     

Robust control of 3-DOF parallel robot driven by PMAs based on nominal stiffness model

This paper deals with an efficient implementation of robust controller on 3-DOF parallel robot driven by pneumatic muscle actuators (PMAs). PMA is a new flexible pneumatic actuator with relatively complex mathematical model. For the purpose of controlling robot, a new method to establish mathematical model of PMA is proposed. Based on analysis of stiffness characteristics of PMA, the concept of nominal stiffness coefficient is put forward and applied to establishment of mathematical model of PMA. According to 3-DOF robotic decoupling property, two rotational freedom of X, Y-axis are controlled by robust controller. Based on the dynamics, trajectory tracking control in simulation performs well under the circumstances of different interference via robust controller. Experimental results show that robust controller has satisfactory tracking performance and the characteristic of high real time. Its maximum tracking errors around X–Y axis are not more than 0.4°. Due to its less interference in motion around Z-axis, controlling Z-axis also has good tracking performance via computed torque method.     

分布式电源在仿人机器人控制系统中的应用

为实现仿人机器人无缆工作的时间更长,设计了采用分布式电源的控制系统.仿人机器人关节电机驱动器采用动力电和数字电分开供电的方式,动力电主要为电机供电,而数字电主要为控制芯片供电,因而采用分布式电源方案,即由一个电池组对多个关节驱动器的数字电部分供电,而对单个关节驱动器的动力电部分由一个电池组供电.该方案在搭建的多电机控制...     

Beat gesture recognition and finger motion control of a piano playing robot for affective interaction of the elderly

This paper introduces a piano playing robot in views of smart house and assistive robot technology to care the affective states of the elderly. We address the current issues in this research area and propose a piano playing robot as a solution. For affective interaction based on music, we first present a beat gesture recognition method to synchronize the tempo of a robot playing a piano with the desired tempo of the user. To estimate the period of an unstructured beat gesture expressed by any part of a body or an object, we apply an optical flow method, and use the trajectories of the center of gravity and normalized central moments of moving objects in images. In addition, we also apply a motion control method by which robotic fingers are trained to follow a set of trajectories. Since the ability to track the trajectories influences the sound a piano generates, we adopt an iterative learning control method to reduce the tracking error.     

基于Fuzzy–CPG的双足机器人适应性行走控制

为提高双足机器人的环境适应性,本文提出了一种基于模糊控制与中枢模式发生器(CPG)的混合控制策略,称之为Fuzzy–CPG算法.高层控制中枢串联模糊控制系统,将环境反馈信息映射为行走步态信息和CPG幅值参数.低层控制中枢CPG根据高层输出命令产生节律性信号,作为机器人的关节控制信号.通过机器人运动,获取环境信息并反馈给高层控制中枢,产生下一步的运动命令.在坡度和凹凸程度可变的仿真环境中进行混合控制策略的实验验证,结果表明,本文提出的Fuzzy–CPG控制方法可以使机器人根据环境的变化产生适应的行走步态,提高了双足机器人的环境适应性行走能力.     

基于CPG的六足机器人运动步态控制方法

中枢模式发生器（CPG）在六足机器人的运动步态控制中起着至关重要的作用。为了研究六足机器人的运动控制方法,首先基于仿生学原理设计了六足机器人的机械结构,并在虚拟样机软件ADAMS中搭建其三维模型;其次选择Hopf振荡器作为CPG单元,并改进了振荡器模型;然后设计了六足机器人的CPG网络拓扑结构,包含单腿关节映射函数方案和腿间CPG环形耦合网络方案,并对其进行了改进;最后通过ADAMS和MATLAB联合仿真实验,验证了所设计六足机器人的运动稳定性和CPG控制方案的可行性与有效性。仿真结果表明,该方法能够满足六足机器人不同运动步态的控制需求,对六足机器人的运动控制具有一定的实际应用价值。     

Petri net modelling and design of task oriented messaging system for robot control

Manufacturing Message Specification (MMS) is an international standard for shop floor machine control. It defines a set of conceptual schema and an interactive software object known as Virtual Manufacturing Device (VMD). Many systems have been established using this protocol but very few formal methods have been used to build such systems. This paper addresses the problems of the design and analysis of a network-based task oriented messaging system for flexible robot task control using a Petri net. The information and message transfer processes of the MMS systems were analysed. The modelling methodology allows a top down approach by which the net model is decomposed into fine details with clear identification of components which can be realised directly from the model. This approach is illustrated in this paper by a Windows-based robot control prototype system implemented from the Petri net model. The prototype was built using Object Windows Library and the NetBIOS session layer protocol on a PC network.     

A robust trajectory tracking control of a polishing robot system based on CAM data

Polishing a die that has free-form surfaces is a time-consuming and tedious job, and requires a considerable amount of high-precision skill. In order to reduce the polishing time and cope with the shortage of skilled workers, a user-friendly automatic polishing system was developed in this research. The polishing system is composed of two subsystems, a three-axis machining center and a two-axis polishing robot. The developed polishing system with five degrees of freedom is able to keep the polishing tool normal to the die surface during operation. A sliding mode control algorithm with velocity compensation is proposed to reduce tracking errors. Trajectory tracking experiments showed that the effect of reducing the tracking error by the proposed sliding mode control is superior to that by the proportional derivative control. The polishing data is generated from computer-aided design (CAD) data or from teaching data by PolyCAM, a computer-aided manufacturing (CAM) system consisting of 4 modules: a geometric modeller, a CAD data exchange module, a polishing data generation module, and a graphic simulator. To evaluate the performance of the polishing robot system, some polishing experiments on a shadow-mask die were performed.     

自由漂浮空间机器人轨迹跟踪的模型预测控制

针对传统控制方法难以解决自由漂浮空间机器人(free-floating space robot, FFSR)轨迹跟踪过程中的各类约束的问题,采用模型预测控制对自由漂浮空间机器人的轨迹跟踪问题进行了研究.在自由漂浮空间机器人拉格朗日动力学模型的基础上,建立了系统伪线性化的扩展状态空间模型;在给定系统的性能指标和各类约束的情况下,基于拉盖尔模型设计相应的离散模型预测控制器,并证明控制器的稳定性,控制器中引入任务空间滑模变量实现了对末端期望位置和期望速度的同时跟踪;以平面二杆自由漂浮空间机器人为例,对无约束末端轨迹跟踪和有约束末端轨迹跟踪两种情况进行对比仿真验证.仿真结果表明,该模型预测控制器不仅可以实现对末端期望轨迹的有效跟踪,还能满足各类约束.     

Application of a hybrid controller to a mobile robot

This paper presents the application of a hybrid controller to the optimization of the movement of a mobile robot. Through hybrid controller processes, the optimal angle and velocity of a robot moving in a work space was determined. More effective movement resulted from these hybrid controller processes. The experimental scenarios involved a five-versus-five soccer game and a MATLAB simulation, where the proposed system dynamically assigned the robot to the target position. The hybrid controller was able to choose a better position according to the circumstances encountered. The hybrid controller that is proposed includes a support vector machine and a fuzzy logic controller. We used the method of generalized predictive control to predict the target position, and the support vector machine to determine the optimal angle and velocity required for the mobile robot to reach the goal. First, we used the generalized predictive control to predict the target position. Then, the support vector machine is used to classify the angle that must be followed by the mobile robot to reach the goal. Next, a fuzzy logic controller is designed to determine the velocity of the left and right wheels of the mobile robot. Thus generated, the velocity was optimized according to the measures obtained by the support vector machine. Finally, based on the optimal velocity of robot, the output membership function was modified. Consequently, the proposed hybrid controller allowed the robot to reach the goal quickly and effectively.     

高压输电线除冰机器人的建模及运动控制

针对高压输电线除冰机器人工作环境的特殊性以及工作任务的复杂性,建立了机器人的运动学与动力学模型。在此基础上,通过采用粒子群算法对PID控制器三个参数进行在线寻优,实现了除冰机器人的运动控制。最后针对除冰机器人在斜坡爬行的情况进行仿真实验,证明了所设计的模型与运动控制方法的可行性。     

基于局部模型逼近的一种绳牵引并联机器人自适应径向基神经网络控制

为了保证风洞试验绳牵引并联机器人(WTT–WDPR)末端执行器的位姿,提出了一种基于局部模型逼近的自适应径向基(RBF)神经网络控制.采用牛顿–欧拉法建立了飞机模型的动力学方程,并基于动态力矩平衡方程建立了驱动系统的动力学方程.采用RBF神经网络进行了局部模型的逼近设计和控制律设计,并通过构建Lyapunov函数对系统...