Thermal Modeling of Robotic Arm and Hand Moving in a Nonhomogeneous Temperature Field

It is said that “human hand” is an agent of the brain. This might attract attention from many prominent robot engineers and researchers who eventually attempted to design multi-fingered robot hands that mimic human hands. In the history of development of multi-fingered robot hands (see the literature [1] ∼ [5]), a variety of sophisticated robot hands designed and make are indeed reported. However, most of them have not yet been used widely in practice such as assembly tasks and other automation lines in place of human hands. The most important reason of this must be owing to the high cost of manufacturing such multi-fingered hands with many joints together with expensive sensing devices such as tactile and/or force sensors, which can not redeem human potentials of flexibility and versatility in execution of a variety of tasks. In fact, multi-fingered robot hands were used only in open-loop control (see [2]) and the importance of sensory feedback was not discussed in the literature until around the year of 2000 (see [12]). This paper firstly introduces a mathematical model of full dynamics of planar but vertical motion a rigid object grasped by a pair of two and three d.o.f fingers with soft and deformable tips whose shape is hemispherical. The behavior of the soft finger tips is lumped-parameterized by assuming that the soft material is distributively composed of massless springs with spring constant k (stiffness constant per unit area) and dampers in parallel.

In this paper, we present a multi-fingered robot hand model with 20 Degrees of Freedom (DoF). We have developed a humaniform robot hand which containts 14 servomotors, equipped with several sensors and a wireless communication set. Based on the proposed design of the multi-fingered robot hand, efficient global model equations have been generated by the Lagrange formulation. Furthermore the dynamic model emphasize the coupling dynamic characteristics. The system is split to seven sub-blocs which can be separately simulated. The passivity approach is proposed and properties are illustrated by simulation results. Several simulation results show that the derived dynamic model can predict the motion of the multi-fingered hand in free motion or in constrained behavior.

This paper deals with two fundamental problems concerning a multi-fingered robotic hand with the capability of compliance control. One of them relates to developing a torque sensor useful for the tendon-pulley driving system and the other was a stable grasping and manipulating problem. In order to construct the finger joint actuation in multifingered systems, a tendon-pulley driving system has normally been used. In this kind of driving system a compact joint torque sensor plays an important role in achieving compliant motions at the finger tip and in turn constructing dextrous multifingered hands. It seems, however, that a satisfactory torque sensor has not yet been developed for such a driving system. To cope with this, a Tension Differential type Torque sensor (TDT sensor) is first proposed in this paper and applied to a newly designed robotic hand with two articulated fingers in experiments. Secondly, the stable grasping and manipulation problems in the multifingered hand are addressed assuming the existence of friction at the contact area of each finger tip and the object grasped. To formulate a stable grasping condition, the stiffness matrix of an object grasped by fingers with compliance adjustable joints was introduced. By using the stiffness components, the condition was described in a simple form. The stiffness matrix was resolved to the simpler form at the tip of each finger when the hand was grasping an object. To satisfy the desired stiffness matrix at the tip, the joint stiffness matrix at each finger was adjusted. To manipulate an object, the desired trajectories of the object were converted to joint trajectories using the inverse kinematics equations, and the position reference at each joint servomechanism was adjusted according to them, keeping the stable grasping condition. A robotic hand with two articulated fingers equipped with specially designed small TDT sensors was constructed. Using the hand, various experiments were carried out and the proposed methods were confirmed.

Two-dimensional thermal analysis of the effect of thermal insulation on the transient temperature distribution of a robotic arm and hand moving in a nonhomogeneous temperature field is presented. A finite-difference scheme is used to find the transient temperature distribution for a composite two-dimensional cylindrical rod moving periodically into and out of a hot environment. One part of the rod simulates the robotic hand with its insulation and the other part simulates the robotic arm. The heat transfer to the surface is by convection and radiation. Due to the periodic motion, the heat transfer coefficient has spatial and time dependence and the environmental condition is time dependent. The effect of thickness of insulation covering the robotic hand on the temperature distribution in the robotic arm and hand for fast, intermediate, and slow transients is studied and discussed.

A multi-fingered hand has been used in the explosive Disposal Robot to improve the disposal ability of explosive. Grasping ability of the multi-fingered hand is a problem with the change of grasping posture. This paper discusses grasping ability of the multi-fingered robot hand. Screw theory and BP neural network are used to optimize the joint angle of the finger. The most favorite grasping posture is calculated when the multi-fingered robot hand can withstand the largest external wrench. In order to guarantee the explosive not to be exploded under the exceeding grasp force, the weight of the explosive the multi-fingered hand can hold is also discussed in this paper. It is an important theoretical guidance for the multi-fingered robot hand handling of hazardous items.

We propose a novel bilateral telemanipulation framework to tame master and slave devices having different structures. This condition applies to multicontact teleoperation scenarios where the number of contact points on the slave side and the number of interaction points on the master side are different. An example is a master device interacting with the thumb and the index fingertips of the human operator, and as slave device, a robotic arm with a multifingered robotic hand. In case of a manipulation task, it is not straightforward to transmit motion commands and reflect forces from the interaction with the environment. A general telemanipulation framework, that does not consider the specific kinematics of the devices involved, is needed. The main idea of this study is to take advantage of a virtual object as a mediator between the master and slave side. The arising forward and backward mapping algorithms are able to relate the motions and the exerted forces of very dissimilar systems. The approach has been evaluated in a case study consisting of two haptic interfaces used both to track the index and thumb motions and to render forces on the master side and a robotic arm with a multifingered hand as end effector on the slave side. The results presented in this paper can be extended to cooperative grasping scenarios where multiple robots telemanipulate the same object.

The paper presents a robotic arm having as end effector an anthropomorphic hand and its control system. The robotic arm and hand are controlled using a Complex Interactive Control Glove (CICG) and operator joint sensors. The robotic hand imitates the finger and joint movements of the human operator. The anthropomorphic hand sends pressure feedback from a pressure sensor array mounted at the robotic hand's fingers and palm to the human operator wearing a Complex Interactive Control Glove that comprises haptic actuators. The pressure exerted by the robotic hand on various objects is perceived as vibrations on the corresponding hand area of the human operator. The robotic arm adjusts its position in correlation with the human operator's arm, placing the end effector at the right position, corresponding to the operator's hand. Data for the movement of the robotic arm are collected from the movements of the human operator by means of three joint sensors placed on the shoulder, elbow and hand wrist. Targeted applications of the tele-operated robotic arm and hand with intuitive control and haptic feedback include all situations where a human-like operation is needed in a hazardous or remote environment: space environment, operations executed in toxic atmosphere, working in high-radiation level environments, marine applications. In such cases, the robotic hand and arm that are executing the same movements as the human operator can replace the actual human operator. This will control the robotic arm form a safe, possibly remote, environment, and will be able to process the haptic feedback of the systems.

Golf balls often become lost in bodies of water due to the nature of the sport and the specific design of its respective courses. Once lost, these balls sink and pollute the water. Not only does this pose a threat to the environment, but these balls can be quite valuable. Our project aims to design and develop an underwater remotely operated vehicle (ROV) with an integrated robotic arm to detect, localize, and collect golf balls. Robotic systems have shown promise in exploring underwater infrastructure and environment field studies. Various hull shapes and thruster configurations have been designed to cater to speed, maneuverability, or a combination of both. The current robotic vacuum arm consists of three 3D-printed links where a motor on the previous link drives the next link. Homogeneous transformation matrices were derived for the three-link robot arm and used to plot the workspace of the unique robotic arm. These matrices were then utilized to help create the Jacobian matrices of the center of mass and geometric centroid of the links so that the torque about the z-axis of the base of the robotic arm could be calculated. The torque at the joints of the robot arm is due to the weight of the robotic arm’s links and the drag due to the links movement. The maximum torque due to these two aspects was calculated as 1.1038 Nm. We found that the Dynamixel XL450-W250 servo motor will suffice for these torque requirements as it can output slightly more than 0.6 Nm of torque at 17.5 rpm. Taking into account the 3.75:1 gear ratio, the servo can output 2.25 Nm of torque to the robotic arm. It is not likely that we will need this maximum torque requirement as we plan to avoid the spaces in the workspace with the greatest torque requirement and will instead move the ROV so the end effector can be used in locations where the required torque is much lower.

This paper presents a tele-control system constructed from a multi-fingered robot hand and operator. The angle of the robot hand is controlled by the angle of the operator’s finger, and the operator feels the environmental force, as detected by the robot hand, constituting so-called bilateral master/slave control.

The 7-DOF humanoid robotic arm joint coordinate systems are established and link parameters are determined by D-H method, and the robotic arm kinematics model is established. The position and orientation of robotic arm end-effector is generated by homogeneous transform method. Monte Carlo method is proposed in analyzing the workspace of robotic arm and the echogram of robotic arm is calculated based on mapping relation from joint space to workspace of robotic arm. The reference basis is provided for follow-up robot trajectory planning, dynamics analysis, and motion control and parameter optimization.

Describes a dexterous and robust manipulation system for mechanical assembly with a multifingered hand. The system is composed of a grasp planner and a real-time execution subsystem. The planner plans an initial grasp from which a required continuous motion of the object is achieved while keeping rolling contact at the fingertips. Task error detection and recovery strategies have been developed based on the task context. The system architecture and experiment results are shown.

Describes a dexterous and robust manipulation system with a multi-fingered hand. The system is composed of a real-time pose estimation of an object manipulated by the hand, a precise manipulation using fingertip with rolling contact, motion primitives for mechanical assembly, and error-recovery strategies based on the task observation function. The system architecture and experimental results are shown.

This paper presents a tele-control system constructed from a multi-fingered robot hand and operator. The angle of the robot hand is controlled by the angle of the operator's finger, and the operator feels the environmental force, as detected by the robot hand, constituting so-called bilateral master/slave control. In the experiments, the operator grasped the object in spite of Round Trip Time (RTT) as Osec, 0.56sec, using a multi-fingered humanoid robot hand by master/slave control feeling fingertip force. However, with increases in the RTT, the operation became more difficult. We also analyzed the stability of the master site and the slave site by frequency characteristics. The results showed that this system was unstable. However, grasping by tele-control with a communication delay was demonstrated.

Multi-finger Robotic hands (MFRH) are desired similar to human hands in order to perform stable grasping and fine manipulation of different objects. Their industrial applications including material handling fulfills the requirement of unique end-effector tool empowering specific reach, payloads, and flexibility. The design and control of dexterous and prosthetic robotic hands is of important concern these days. The performance of these hands depends on their mechanical design, prosthetics etc. The mechanical range of movement must be properly controlled and monitored to get the best performance of the robotic hand. In order to obtain the desired outcome from these robotic hands, various design parameters are discussed. The control issues of the multi-finger hand-arm system in order to interact with the human environment are also discussed. The objective of this paper is to evaluate multi-finger robotic hands capable of grasping a large variety of products. An overview of the relations between the designing features for the robotic hand, its anthropomorphism and dexterity is reported. Also, the best known robotic hands developed so far are reviewed emphasizing on their ergonomics and mechanical features. Based on these parameters, a newly designed four fingered tendon actuated robotic hand is discussed along with its mechanical structure.

This paper describes a geometrical method for grasping objects wherein an object is caged by rigid parts of a robot hand and simultaneously grasped by soft parts attached to said rigid parts. We term this process as caging-based grasping. In this study, we derive concrete conditions for two- and three-dimensional caging-based grasping of objects of various shapes using circular robots and multi-fingered robot hands. Then, we validate the derived conditions by performing caging-based grasping experiments.