螺旋型光纤传感软体操作臂状态测量及特性分析

微创手术软体操作臂是微创外科和机器人领域的科学前沿和研究热点,对提升微创手术水平至关重要。现有视觉、电子和光电等传感方法尚未解决软体操作臂的状态测量问题,以直线型布设在软体操作臂中的光纤传感器,在柔性操作臂伸展和弯曲等运动时存在易断裂和可重复性差等问题,未能实现手术操作臂的闭环控制,限制了其手术应用。为此,提出了一种基于螺旋型光纤传感的软体操作臂状态测量方法,并对其传感特性进行了研究。不同于直线布设光纤的传感方法,螺旋型布设光纤的传感方法可以实现可伸缩软体操作臂的测量,防止光纤在软体操作臂中的错位,满足可伸缩弯曲软体操作臂的测量需求。通过理论分析气动驱动软体操作臂伸缩和弯曲的运动特性,利用光纤上刻写的布拉格光栅传感点,建立软体操作臂中螺旋型光纤光栅的传感模型,推导出光纤光栅中心波长漂移量和软体操作臂弯曲曲率之间的关系。最后,为了验证螺旋型光纤光栅在软体操作臂中的传感性能,对其传感灵敏度和稳定性等进行了实验测试。实验结果表明:提出的螺旋型光纤传感方法可实现操作臂伸长10%、弯曲角度达到180°时的状态测量,且操作臂理论弯曲角度和光纤传感的误差最大为9%,传感灵敏度可达12.55 pm/(°),满足软体操作臂伸缩和各向弯曲操作时的测量需求。     

双臂六自由度空间机器人广义雅可比矩阵的推导

本文建立了双臂六自由度空间机器人的运动学模型,基于此模型,推导出描述机械手末端运动速度与各关节运动速度关系的广义雅可比矩阵(GJM).较现有的其他推导GJM方法相比,导出的GJM求解公式显式、易求,可直接对GJM表达式中各参数赋值,求出GJM.本文的建模方法适合采用分解运动速度(RMRC)控制方法.计算机仿真中,给出了基于RMRC控制方法,利用本文导出的GJM求解公式实现了对机械臂的运动控制.     

The hybrid OmniClimber robot: Wheel based climbing,arm based plane transition,and switchable magnet adhesion

Climbing robots that integrate an articulated arm as their main climbing mechanism can eventually take advantage of their arm for plane transition and thus to operate on 3D structures rather than only climbing planar surfaces. However, they are usually slower than wheel based climbing robots. Within this research we address this problem by integration of a light-weight arm and adhesion mechanism into an omnidirectional wheel based climbing robot, thus forming a hybrid mechanism that is agile in climbing and still able to perform plane transition. A 2DOF (Degree of Freedom) plannar mechanism with 2 linear actuators was designed as a light-weight manipulator for the transition mechanism. Furthermore, we customized and developed actuated switchable magnets both for the robot chassis and also as the adhesion unit of the arm. These units allow us to control the amount of magnetic adhesion force, resulting in better adaptation to different surface characteristics. The adhesion units are safe for climbing applications with a very small power consumption. The conceptual and the detailed design of the mechanisms are presented. The robots were developed and successfully tested on a ferromagnetic structure.     

Application of Photoelectric Devices to Robot Soft Grasp

A robot slide tactile sensor based on photoelectric devices is introduced.The sensor is mounted on the hydraulic manipulator and used in a soft grasp control system.The experimental results are also presented.     

Stable visual servoing of camera-in-hand robotic systems

In this paper, the control problem of camera-in-hand robotic systems is considered. In this approach, a camera is mounted on the robot, usually at the hand, which provides an image of objects located in the robot environment. The aim of this approach is to move the robot arm in such a way that the image of the objects attains the desired locations. We propose a simple image-based direct visual servo controller which requires knowledge of the objects' depths, but it does not need to use the inverse kinematics and the inverse Jacobian matrix. By invoking the Lyapunov direct method, we show that the overall closed-loop system is stable and, under mild conditions on the Jacobian, local asymptotic stability is guaranteed. Experiments with a two degrees-of-freedom direct-drive manipulator are presented to illustrate the controller's performance     

Structural design, analysis, and performance evaluation of a new semi-direct drive robot arm: theory and experiment

This paper reports the mechanical design, structural analysis, and experimental verification of a new high-performance semi-direct drive robot arm. A design-optimization methodology employing finite element analysis (FEA) is reviewed, and a resulting arm design is reported. FEA simulations of the final design predict high structural vibration frequencies throughout the arms workspace. Extensive structural vibration experiments with the completed manipulator confirm the predicted structural vibration characteristics throughout the arm's workspace. Position-tracking experiments show that the manipulator accurately tracks fast time-varying reference trajectories-peak tip velocities greater than 6 m/s and peak tip accelerations greater than 7 g.     

基于STM32的智能搬运机器人的研究与设计

针对老年人和行动不便者日常生活困难的问题,设计了一款可以进行基本日常操作的智能搬运机器人。机器人以STM32单片机为主控制器,通过红外线、超声波等传感器获取外界环境信息,对履带式行走机构和机械臂进行控制。履带结构较为平稳,具有良好的越障能力;机械臂自由度高,可完成360度全方位无死角的的抓取活动。本文使用Creo进行建模,实现机器人的运动仿真,优化机器人机械结构,借助Keil进行程序编译,解决机器人运动的算法问题。智能机器人利用多个传感器作为“感觉器官”,凭借稳定的履带行走机构和高自由度的机械臂,实现超声避障、智能循迹、定距抓取等多个功能。     

基于STM32的语音控制机械手

智能机器人技术为近年来研究热点,机械手在智能机器人教学研究与工业机器人领域占据很大比例,本文设计实现了基于STM32为控制平台的四自由度机械手控制系统,系统可以调试,存储机械手动作,并且使用语音控制模块,使机械手具备人机对话,语音控制功能。系统高效,灵活,使用方便,对于智能机器人研究教学,工业机械人控制系统研发具有重大意义     

The design and control of a therapeutic exercise robot for lower limb rehabilitation: Physiotherabot

This study explains the design and control of three degrees of freedom therapeutic exercise robot (Physiotherabot) for the lower limbs of a patient who needs rehabilitation after a spinal cord injury (SCI), stroke, muscle disorder, or a surgical operation. In order to control this robot, a “Human-Machine Interface” with a rule-based control structure was developed. The robot manipulator (RM) can perform all active and passive exercises as well as learn specific exercise motions and perform them without the physiotherapist (PT) through the Human-Machine Interface. Furthermore, if a patient reacts against the robot manipulator during the exercise, the robot manipulator can change the position according to feedback data. Thus, the robot manipulator can serve as both therapeutic exercise equipment and as a physiotherapist in terms of motion capability. Experiments carried out on healthy subjects have demonstrated that the RM can perform the necessary exercise movements as well as imitate the manual exercises performed by the PT.     

Effects of joint dynamics on the dynamic manipulability of geared robot manipulators

Information obtained through the analysis of dynamic manipulability can be useful in the design and control of robotic manipulators. In this paper, we investigate the influences of the joint drive systems on the dynamic manipulability, with special attention to the effects of gear reduction ratios. In order to reflect this influence, a new form of the dynamic manipulability ellipsoid is developed, which includes the gear reduction ratios, and a modified formula is derived for the dynamic manipulability measure. This formula indicates that joint drive dynamics can significantly influence the dynamic manipulability of a robot. The most important effect is that changing the gear reduction ratios modifies the nature of the dynamic manipulability distribution throughout the workspace of the manipulator. Examples of a two-link planar arm and a PUMA 560 robot are presented to illustrate the results.     

Application of rubber artificial muscle manipulator as arehabilitation robot

The application of a robot to rehabilitation has become a matter of great concern. This paper deals with functional recovery therapy, one important aspect of physical rehabilitation. Single-joint therapy machines have already been achieved. However, for more efficient therapy, multjoint robots are necessary to achieve more realistic motion patterns. This kind of robot must have a high level of safety for humans. A pneumatic actuator may be available for such a robot, because of the compliance of compressed air. A pneumatic rubber artificial muscle manipulator has been applied to construct a therapy robot with two degrees of freedom (DOF). Also, an impedance control strategy is employed to realize various motion modes for the physical therapy modes. Further, for efficient rehabilitation, it is desirable to comprehend the physical condition of the patient. Thus, the mechanical impedance of the human arm is used as an objective evaluation of recovery, and an estimation method is proposed. Experiments show the suitability of the proposed rehabilitation robot system     

Inverse Double NARX Fuzzy Modeling for System Identification

In this paper, a novel inverse double nonlinear autoregressive with exogenous input (NARX) fuzzy model is applied to simultaneously model and identify both joints of the prototype two-axis pneumatic artificial muscle (PAM) robot arm's inverse dynamic model. Highly nonlinear features of both joints of the nonlinear manipulator system are identified by the proposed inverse double NARX fuzzy (IDNF) model based on experimental input–output training data. The modified genetic algorithm (GA) optimally generates the appropriate fuzzy if–then rules to perfectly characterize the dynamic features of the two-axis PAM manipulator system. The evaluation of different IDNF models with various ARX model structures will be discussed. For the first time, the nonlinear IDNF model of the two-axis PAM robot arm is investigated. The results show that the nonlinear IDNF model that is trained by GA performs better and has a higher accuracy than the conventional inverse fuzzy model.      

A Microprocessor-Based Robot Manipulator Control with Sliding Mode

The application of a sliding-mode control based on a Variable Structure System (VSS) for a multijoint manipulator is presented. The high-gain effect of a sliding-mode control suppresses the complicated interactions between each joint of a robot arm. The resulting system is completely robust whereas the obtained control law is simple and easy to apply to on-line computer control. In this-paper, the practical sliding-mode controller, which has a simple nonlinear compensator and proper continuous function, is implemented for a two-linkage manipulator. The validity of this technique is confirmed in experiments where the system shows robust performance in spite of the existing nonlinear interactions and unknown parametric changes. In addition, this sliding-mode control is improved to track the desired path.     

Adaptive neural network based controller for robots

A new Adaptive Neural Network (ANN) controller for robot trajectory trackingproblem is developed. A novel and efficient training algorithm for the proposed controller ispresented in this paper. The proposed training algorithm is based on updating the weights of thenetwork each step by minimizing the quadrant tracking errors and their derivatives.A simulation study is carried out on a polar robot manipulator to assure the effectivenessof the proposed trajectory tracking robot control system. The effects of the new controllerparameters and noisy external load disturbances on the control performance are studied. Thesimulation results of the proposed adaptive ANN controller are compared with those of aconventional ANN controller. The obtained results assured the robustness of the proposed ANNcontroller for: (i) uncertainties of the robot arm dynamic model and/or parameters, (ii) variousnoisy external load disturbances. Also, the simulation results assure the effectiveness of theproposed adaptive ANN controller against the conventional ANN one.     

Calculation of a robot manipulator model in the form of arecurrent neural net

A neural model for robot manipulator is proposed similar to the mathematical model of a robot manipulator in the form of a Lagrange-Euler equation. A learning algorithm based on the backpropagation method is given for a neural model. A numerical example of calculation of a neural model for Puma 560 robot is presented.     

Control of a multijoint manipulator "Moray arm"

We introduce a multijoint manipulator that was named "Moray arm", which is a slider-integrating multijoint manipulator, where a powerful slider is installed at the base of the arm. The Moray arm emulates the motion of a Moray, thus, allowing it to easily enter a narrow space while avoiding obstacles. To elucidate the features of the Moray arm, we present new control methods named "Moray drive" and "two-degrees-of-freedom (2-DOF) Moray drive". The Moray drive control generates rotating motion of the joints in synchronization with linear motion of the slider while restricting the arm on the trajectory. The 2-DOF Moray drive control reduces the control problem of the hyper DOFs to the simple one of 2-DOFs: one of the control variables signifies the linear combination of the objective initial and final postures of the arm, while another expresses the amount of the pull-out-displacement when pulling the arm out of the housing. The properties of Moray arm controlled by Moray drive or 2-DOF Moray drive are described. Based on the 2-DOF Moray drive control, we also propose an obstacle avoidance scheme for the "Moray arm" to perform a pick-and-place task while avoiding the existing static obstacles in environment. The scheme is based on the posture space analysis and generates the obstacle collision-free trajectory in the posture space. From the simulation result, we conclude that the Moray arm controlled by the proposed schemes gives great possibility for the hyper-redundant manipulator to perform applications such as maintenance of nuclear reactors, collection of lumps of existing manganese under sea, and care of patients.     

Optimization of a spherical mechanism for a minimally invasive surgical robot: theoretical and experimental approaches

With a focus on design methodology for developing a compact and lightweight minimally invasive surgery (MIS) robot manipulator, the goal of this study is progress toward a next-generation surgical robot system that will help surgeons deliver healthcare more effectively. Based on an extensive database of in-vivo surgical measurements, the workspace requirements were clearly defined. The pivot point constraint in MIS makes the spherical manipulator a natural candidate. An experimental evaluation process helped to more clearly understand the application and limitations of the spherical mechanism as an MIS robot manipulator. The best configuration consists of two serial manipulators in order to avoid collision problems. A complete kinematic analysis and optimization incorporating the requirements for MIS was performed to find the optimal link lengths of the manipulator. The results show that for the serial spherical 2-link manipulator used to guide the surgical tool, the optimal link lengths (angles) are (60 degrees, 50 degrees). A prototype 6-DOF surgical robot has been developed and will be the subject of further study.     

Design and control of robot manipulator with a distributed actuation mechanism

This paper presents a design methodology based on the distributed actuation principle to achieve a high-performance robot manipulator. Spatial movement of the actuation points provides several advantages such as high payload capacity, high efficiency and a light weight structure for the proposed robot manipulator. Based on the analysis, the distributed actuation mechanism using a single slider is adopted for the proposed manipulator. A prototype of the manipulator with two degrees of freedom is developed and controlled as an example. The efficacy of the proposed approach is verified experimentally.     

Articulated hybrid mobile robot mechanism with compounded mobility and manipulation and on-board wireless sensor/actuator control interfaces

This paper presents the development of a remotely operated mobile robot system with a hybrid mechanism whereby the locomotion platform and manipulator arm are designed as one entity to support both locomotion and manipulation interchangeably. The mechanical design is briefly described as well as the dynamic simulations used to analyze the robot mobility and functionality. As part of the development, this paper mainly focuses on a new generalized control hardware architecture based on embedded on-board wireless communication network between the robot’s subsystems. This approach results in a modular control hardware architecture since no wire connections are used between the actuators and sensors in each of the mobile robot subsystems and also provides operational fault-tolerance. The effectiveness of this approach is experimentally demonstrated and validated by implementing it in the hybrid mobile robot system. The new control hardware architecture and mechanical design demonstrate the qualitative and quantitative performance improvements of the mobile robot in terms of the new locomotion and manipulation capabilities it provides. Experimental results are presented to demonstrate new operative tasks that the robot was able to accomplish, such as traversing challenging obstacles, and manipulating objects of various capacities; functions often required in various challenging applications, such as search and rescue missions, hazardous site inspections, and planetary explorations.