An exoskeletal robot for human shoulder joint motion assist

We develop exoskeletal robots to assist the motion of physically weak persons such as elderly persons or handicapped persons. In our previous research (2001), a prototype of a two degree of freedom exoskeletal robots for shoulder joint motion assist have been developed. In this paper, we propose an effective fuzzy-neuro controller, a moving mechanism of the center of rotation (CR) of the shoulder joint of the exoskeletal robot, and an intelligent interface in order to realize a practical and effective exoskeletal robot for shoulder joint motion assist. The fuzzy-neuro controller enables the robot to assist a person's shoulder motion. The moving mechanism of the CR of the robot shoulder joint is used to fit the CR of the robot shoulder joint to that of the physiological human shoulder joint during the shoulder motion. The intelligent interface is realized by applying a neural network and used to cancel out the effect the human subject's arm posture change. The effectiveness of the proposed method was evaluated by experiment.     

Redundancy resolution of the human arm and an upper limb exoskeleton

The human arm has 7 degrees of freedom (DOF) while only 6 DOF are required to position the wrist and orient the palm. Thus, the inverse kinematics of an human arm has a nonunique solution. Resolving this redundancy becomes critical as the human interacts with a wearable robot and the inverse kinematics solution of these two coupled systems must be identical to guarantee an seamless integration. The redundancy of the arm can be formulated by defining the swivel angle, the rotation angle of the plane defined by the upper and lower arm around a virtual axis that connects the shoulder and wrist joints. Analyzing reaching tasks recorded with a motion capture system indicates that the swivel angle is selected such that when the elbow joint is flexed, the palm points to the head. Based on these experimental results, a new criterion is formed to resolve the human arm redundancy. This criterion was implemented into the control algorithm of an upper limb 7-DOF wearable robot. Experimental results indicate that by using the proposed redundancy resolution criterion, the error between the predicted and the actual swivel angle adopted by the motor control system is less then 5°.     

Upper-Limb Powered Exoskeleton Design

An exoskeleton is an external structural mechanism with joints and links corresponding to those of the human body. With applications in rehabilitation medicine and virtual reality simulation, exoskeletons offer benefits for both disabled and healthy populations. A pilot database defining the kinematics and dynamics of the upper limb during daily living activities was one among several factors guiding the development of an anthropomorphic, 7-DOF, powered arm exoskeleton. Additional design inputs include anatomical and physiological considerations, workspace analyses, and upper limb joint ranges of motion. The database was compiled from 19 arm activities of daily living. The cable-actuated dexterous exoskeleton for neurorehabilitation (CADEN)-7 offers remarkable opportunities as a versatile human-machine interface and as a new generation of assistive technology. Proximal placement of motors and distal placement of cable-pulley reductions were incorporated into the design, leading to low inertia, high-stiffness links, and backdrivable transmissions with zero backlash. The design enables full glenohumeral, elbow, and wrist joint functionality. Potential applications of the exoskeleton as a wearable robot include: 1) a therapeutic and diagnostics device for physiotherapy, 2) an assistive (orthotic) device for human power amplifications, 3) a haptic device in virtual reality simulation, and 4) a master device for teleoperation.     

Design and control of tele-matched surgery robot

In the present paper, we develop a tele-matched surgery robot for a precise force reflection, and stable and intuitive operation. The term ‘tele-matched’ means that the motions of master and slave robots are matched precisely by bilateral teleoperation. The developed tele-matched surgery robot has three main features: (1) Coupling forces among joints of slave end-effector are removed. (2) Power transmission mechanism of slave robot is designed suitable enough for torque estimation without a torque sensor. (3) The motion of each joint of master robot precisely matches to that of slave robot. Consequently, as the key contributions of this paper, a new tendon mechanism is designed to remove the coupling forces, a torque estimation scheme is used to estimate the external forces without using any physical sensors, and by the motion matching between the master and slave robots, a surgeon can operate the slave motion by intuitively controlling the master device. The effectiveness of the developed robot is verified through a number of experiments.     

4-DOF多功能机器人运动控制算法的研究

随着机器人技术的不断发展,机器人在现在社会发展中发挥着越来越重要的作用。文中对实验室研发的多功能4-DOF机器人的运动控制相关问题进行研究。首先对4-DOF机器人的机构整体设计并PROE三维建模,然后通过基于D-H法建立机械臂坐标系,对4-DOF机器人进行运动学正逆解分析,在逆解计算中,提出了当两轴平行两轴耦合的计算方法,即将两轴关节角视为整体计算,再利用代数方法依次得出单个关节角。同时针对机械臂的连续轨迹运动给出轨迹规划的方法,为设计机械臂控制器的实现和机械臂的运动控制提供了依据。     

Design and Characterization of Hand Module for Whole-Arm Rehabilitation Following Stroke

In 1991, a novel robot named MIT-MANUS was introduced as a test bed to study the potential of using robots to assist in and quantify the neurorehabilitation of motor function. It introduced a new modality of therapy, offering a highly backdrivable experience with a soft and stable feel for the user. MIT-MANUS proved an excellent fit for shoulder and elbow rehabilitation in stroke patients, showing a reduction of impairment in clinical trials with well over 300 stroke patients. The greatest impairment reduction was observed in the group of muscles exercised. This suggests a need for additional robots to rehabilitate other target areas of the body. Previous work has expanded the planar MIT-MANUS to include an antigravity robot for shoulder and elbow, and a wrist robot. In this paper we present the ldquomissing linkrdquo: a hand robot. It consists of a single-degree-of-freedom (DOF) mechanism in a novel statorless configuration, which enables rehabilitation of grasping. The system uses the kinematic configuration of a double crank and slider where the members are linked to stator and rotor; a free base motor, i.e., a motor having two rotors that are free to rotate instead of a fixed stator and a single rotatable rotor (dual-rotor statorless motor). A cylindrical structure, made of six panels and driven by the relative rotation of the rotors, is able to increase its radius linearly, moving or guiding the hand of the patients during grasping. This module completes our development of robots for the upper extremity, yielding for the first time a whole-arm rehabilitation experience. In this paper, we discuss in detail the design and characterization of the device.     

次镜支撑小型三自由度机构动力学及控制策略

提出了利用一种可实现一个移动和两个转动的小型3自由度（3-DOF）并联机构来支撑并控制次镜,以达到激光精确聚焦目的的方案。通过对小型3-PRS机构的运动模式分析,采用欧拉角描述动平台的运动方式,对其运动学特性做了简要分析。引入该机构连接杆的质量分布因子,利用虚功原理建立了逆动力学模型。基于建立的动力学模型,提出了两种控制策略方案。利用ADAMS/Control模块和MATLAB/Simulink模块联合仿真了该机构的控制精度。最后将该机构应用于实际光路系统中,测量了两种控制方案下该机构控制的调焦次镜对聚焦光斑性能的影响。仿真结果充分证明了该机构完全满足支撑激光聚焦次镜结构的设计要求。     

Novel 3-DOF counterbalance mechanism based on spring balancer for mobile robot arms

Mobile robot arms have been recently used in service sites. However, their payload is usually small due to the limitation of battery capacity, making it difficult to perform various tasks. Counterbalance mechanism (CBM), a mechanical device that compensates for gravitational torque or force acting on the robot, is one of the good solutions to this payload limit. However, conventional CBMs are focused only on revolute joints, so their application to mobile robot arms possessing a prismatic joint is limited. Therefore, we propose a 3-DOF CBM that counterbalances a robot with prismatic–pitch–pitch joints utilizing only one spring balancer. One prismatic joint and two pitch joints are counterbalanced through a single wire, which is subjected to a constant restoring force generated by a base-mounted spring balancer, and each link of the CBM is only equipped with small idlers. Thanks to this unique structure of the proposed 3-DOF CBM, its application to mobile robot arms can efficiently enhance the payload performance with a minimal increase in volume and mechanical complexity. The experiments confirmed that the proposed CBM and the mobile robot arm equipped with it can properly counterbalance all joints of the arm.     

3DCLIMBER: Climbing and manipulation over 3D structures

This paper describes the development of a novel pole climbing robot with the ability of climbing and manipulating across 3D structures, like petrochemical pipelines. The robot consists of a 4-DOF serial climbing mechanism and two grippers. Unlike many other developed pole climbing robots, 3DCLIMBER can overcome bends, T-junctions, flanges, and sharp changes on the pole’s diameter. With the current gripper, the robot can operate on circular profiles with diameters ranging from 200 mm to 350 mm and is able to scan the exterior surface of the pole. Existence of separate gripping and climbing modules allows application of various grippers for different profile shapes and sizes without any change on the climbing mechanism. In case of power failure the robot maintains its status without slipping on the structure. Furthermore, some nondestructive test operations require fine manipulation over the structure. Fine manipulation with an industrial arm encounters many well known difficulties. Such difficulties become even more problematic when the base of the robot’s arm is mobile. This problem was addressed by a robotic proprioception solution embedded into the robot by integration of inclinometers and range finder sensors as well as error compensation and self calibration algorithms. The proposed algorithms and sensors significantly improved the manipulation accuracy of the robot.     

Optimal kinematic design of a haptic pen

This paper investigates the performance demands of a haptic interface and shows how this information can be used to design a suitable mechanism. A design procedure, previously developed by the authors (1996), consisting of a global isotropy index and a discrete optimization algorithm, allows one to compare a range of geometric variables, actuator scale factors, and even different robot devices for optimum performance. The approach is used to compare the performance of three 6-DOF robots including two well-known parallel platform robots and a novel hybrid robot called the Twin-Pantograph in terms of their semi-dextrous workspaces and static force capabilities. Since the Twin-Pantograph yields the best results, its design is refined to address practical constraints and it is implemented as a haptic pen. The performance of the resulting design is analysed and presented     

A real-time optical sensor for simultaneous measurement of three-DOF motions

The need for simultaneous measurement of multiple degree-of-freedom (DOF) motions can be found in numerous applications such as robotic assembly, precision machining, optical tracking, wrist actuators, and active joysticks. Conventional single-axis encoders, though capable of providing high-resolution (linear or angular) measurements, rely on mechanical linkages (that often introduce frictions, backlashes, and singularities) to constrain the device so that the three-DOF (3-DOF) motion can be deduced from the individual orthogonal measurements. We present here a noncontact optical sensor for 3-DOF planar and spherical orientation measurements. We begin with the operational principle of a microscopic-surface-based optical sensor. The design concept and theory of a dual-sensor system capable of measuring 3-DOF planar and spherical motions in real time are then presented. Along with a detailed analysis, the concept feasibility of two prototype 3-DOF dual-sensor systems for measuring the instantaneous center of rotation and the angular displacement of a moving surface is demonstrated experimentally. It is expected that the analysis will serve as a basis for optimizing key design parameters that could significantly influence the sensor performance.     

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.     

Networked telemicromanipulation systems "Haptic Loupe"

In this paper, "Haptic Loupe" telemicromanipulation systems are proposed. We have developed telemicromanipulation systems that enable human operators to perform micro tasks, such as assembly or manufacturing without stress . These systems are based on a scaled bilateral teleoperation system between different structures. The systems are composed of an original six-degrees-of-freedom (6-DOF) parallel link manipulator to carry out micromanipulation and a 6-DOF haptic interface with force feedback. A parallel mechanism is adopted as a slave micromanipulator because of its good features of accuracy and stiffness. The haptic master interface is developed for micromanipulation systems. Haptic device system modeling and a model reference adaptive controller are implemented to compensate for friction forces, which spoil the free motion performance and force response isotropy of the system. Total system performance as a telemicromanipulator system is evaluated by performing some primitive manipulation tasks in a teleoperation experiment. Experimental results are presented and discussed.     

5-DOF并串联机器人运动学分析及仿真

并联机器人强度刚度较高,但是工作空间较小;串联机器人工作空间较大,但强度刚度较小。混联机构因兼顾了并联和串联机构的优点而具有更加广泛的应用前景。文中介绍了一种新型五自由度并串联机器人来实现复杂曲面的加工。应用螺旋理论对其运动性质进行分析并计算了自由度。通过数值法推导了机器人的正解,运用解析法推导了机器人的反解。用SolidWorks构建了机器人的三维模型并导入到ADAMS中对其进行运动学仿真。仿真结果显示,该机器人能够实现复杂曲面的加工,可以为工业生产提供帮助。     

Development of micromanipulator and haptic interface for networkedmicromanipulation

Telemicromanipulation systems with haptic feedback, which are connected through a network, are proposed. It is based on scaled bilateral teleoperation systems between different structures. These systems are composed of an original 6 degree of freedom (DOF) parallel link manipulator to carry out micromanipulation and a 6-DOF haptic interface with force feedback. A parallel mechanism is adopted as a slave micromanipulator because of its good features of accuracy and stiffness. The system modeling and control of the parallel manipulator system are conducted. Parallel manipulator feasibility as a micromanipulator, positioning accuracy and device control characteristics are investigated. A haptic master interface is developed for micromanipulation systems. System modeling and a model reference adaptive controller are applied to compensate friction force, which spoils free motion performance and force response isotropy of the haptic interface. These systems aim to make the micromanipulation more productive constructing a better human interface through the microenvironment force and scale expansion     

A cooperative multi-robot architecture for moving a paralyzed robot

In this paper we study the possibility of cooperation between reactive and deliberative based robots, which are generally considered as antinomic approaches. We focus on a case study composed, on the one hand, of an “intelligent” robot that submits failures which prevent it from moving, and on the other hand, of a pool of simple autonomous mobile robots which are able to push. The paralyzed robot can broadcast signals to recruit mobile robots and to be pushed by them. These signals are interpreted as force fields by agents in order to compute their reactive behavior. We present these different robot behaviors and analyse two experiments. We show that the proposed system provides a control loop which is independent of the number of robots pushing on each arm, showing that a combination of multi-agent and deliberative architectures can define intelligent and robust multi-robot systems.     

Upper Extremity Limb Function Discrimination Using EMG Signal Analysis

A signal analysis technique is developed for discriminating a set of lower arm and wrist functions using surface EMG signals. Data wete obtained from four electrodes placed around the proximal forearm. The functions analyzed included wrist flexion/extension, wrist abduction/adduction, and forearm pronation/supination. Multivariate autoregression models were derived for each function; discrimination was performed using a multiple-model hypothesis detection technique. This approach extends the work of Graupe and Cline [1] by including spatial correlations and by using a more generalized detection philosophy, based on analysis of the time history of all limb function probabilities. These probabilities are the sufficient statistics for the problem if the EMG data are stationary Gauss-Markov processes. Experimental results on-normal subjects are presented which demonstrate the advantages of using the spatial and time correlation of the signals. This technique should be useful in generating control signals for prosthetic devices.     

基于Kinect体感器的康复机械手臂系统算法设计与实现

设计实现一种新的机械手臂康复系统。利用Kinect体感器获取人体右肩、右肘和右腕3个关节的三维坐标,计算得出所需控制参数。建立体感器与机械手臂之间通信机制,通过数据反馈调整所需控制参数。实现多自由度同时协调运动的康复型机械手臂控制方法。实验表明,该系统控制下的机械手臂能够平滑无明显停顿感地模仿人类手臂的自然动作,提高患者使用时的舒适度,增强康复效果。     

Real-time static deflection compensation of an LCD glass-handling robot

Progress in the LCD industries has been very rapid and the demand for large LCD panel has also been increasing. Therefore, LCD device makers have invested in manufacturing line which uses larger mother glasses than before. As the size of mother glass is larger, LCD glass-handling robots also get larger. The large robot causes unavoidable static deflection of the arm inherently. This static deflection should be compensated to stack maximum mother glasses on the given footprint. This paper presents a novel static deflection compensation algorithm. This algorithm does not need any measurement instrument and additional vertical axis on the robot. It can be realized by robot controller software only. The forward and inverse kinematics considering compensation always guarantee a unique solution, so that the proposed algorithm can be applied to an arbitrary robot position. The proposed algorithm reduces static deflection by 40% in stationary robot state experiment. Furthermore, when the robot arm moves with the maximum speed, static deflection compensation improves vertical path accuracy up to 60%. This algorithm has been commercialized and applied to the 7th generation LCD glass-handling robot.     

The Tricept robot: dynamics and impedance control

The Tricept is a novel industrial robot characterized by a hybrid kinematic design featuring a three-degrees-of-freedom (3-DOF) structure of parallel type and a 3-DOF spherical wrist. In this work the authors focus on the derivation of a dynamic model to be used for both simulation and control purposes. Two different approaches are discussed and compared in terms of inverse dynamics computation. Then, a model-based control is derived aimed at enforcing a 6-DOF impedance behavior at the end effector to manage interaction with the environment. Simulation results are presented to evaluate the accuracy of an approximate dynamic model computation as well as to test the effectiveness of the proposed impedance control strategy.