In the paper, a new method named Cartesian Space Synchronous Impedance Control (CSSIC) has been developed. The method combines the synchronous control and the impedance control together which can not only be used in the position control but can also realize the purpose of force control of the system with multi-manipulators. Therefore, if there are multi-manipulators grasping the same object, it can ensure the object will not fall and not be destroyed. The mathematical validation process and the stability proof of the method have been given. Besides, an experiment setup which has two 7-DOF robot arms has been established to testify the method. The testing result shows that the dual arm system, under disturbance, can ensure stable grasping of the object with the CSSIC method.

This paper presents experimental results on the five-finger dexterous robot hand DLR-HIT II, with Cartesian impedance control based on joint torque and nonlinearity compensation for elastic dexterous robot joints. To improve the performance of the impedance controller, system parameter estimations with extended kalman filter and gravity compensation have been investigated on the robot hand. Experimental results show that, for the harmonic drive robot hand with joint toruqe feedback, accurate position tracking and stable torque/force response can be achieved with cartesian and joint impedance controller. In addition, a FPGA-based control architecture with flexible communication is proposed to perform the designed impedance controller.

This paper presents a new developed multisensory five-fingered dexterous robot hand: the DLR/HIT Hand II. The hand has an independent palm and five identical modular fingers, each finger has three DOFs and four joints. All the actuators and electronics are integrated in the finger body and the palm. By using powerful super flat brushless DC motors, tiny harmonic drivers and BGA form DSPs and FPGAs, the whole fingerpsilas size is about one third smaller than the former finger in the DLR/HIT Hand I. By using the steel coupling mechanism, the phalanx distalpsilas transmission ratio is exact 1:1 in the whole movement range. At the same time, the multisensory dexterous hand integrates position, force/torque and temperature sensors. The hierarchical hardware structure of the hand consists of the finger DSPs, the finger FPGAs, the palm FPGA and the PCI based DSP/FPGA board. The hand can communicate with external with PPSeCo, CAN and Internet. Instead of extra cover, the packing mechanism of the hand is implemented directly in the finger body and palm to make the hand smaller and more human like. The whole weight of the hand is about 1.5Kg and the fingertip force can reach 10N.

This paper presents a new developed multisensory five-fingered dexterous robot hand : the DLR/HIT Hand II. The hand has an independent palm and five identical modular fingers, each finger has three DOFs and four joints. All the actuators and electronics are integrated in the finger body and the palm. By using powerful super flat brushless DC motors, tiny harmonic drives and BGA form DSPs and FPGAs, the whole fingerpsilas size is about one third smaller than the former finger in the DLR/HIT Hand I. By using the steel coupling mechanism, the phalanx distalpsilas transmission ratio is exact 1:1 in the whole movement range. At the same time, the multisensory dexterous hand integrates position, force/torque and temperature sensors. The hierarchical hardware structure of the hand consists of the finger DSPs, the finger FPGAs, the palm FPGA and the PCI based DSP/FPGA board. The hand can communicate with external with PPSeCo , CAN and Internet. Instead of extra cover, the packing mechanism of the hand is implemented directly in the finger body and palm to make the hand smaller and more human like. The whole weight of the hand is about 1.5 Kg and the fingertip force can reach 10N.

This paper gives an overview of the Chinese intelligent space robotic system. The system consists of a 6 DOF robot arm, a large-error tolerated gripper with two stereo cameras and onboard computer. The robot arm is composed of six identical modular joints, a big central hole in the modular joint was designed for the placement of the cables and plugs in the robot arm, which prevented them from damage of high temperature, radiation in the space environment and the motion of the robot. Joint torque sensor, joint position sensor and temperature sensors etc.., were integrated into the fully modular multi-sensory joint, which made the joint more intelligent. Also, a large-error tolerated gripper with two stereo cameras has been also designed to capture a microtarget satellite (MTS). A fault-tolerant onboard computer (OBC) with dual processing modules has been developed for the robot control. A zero gravity experimental system was developed to verify the functions of the robot arm under zero gravity environment

The cost and risks associated with the execution of robotics tasks in space require that all procedures be verified on Earth prior to their execution. The DLR-HIT Joint Robotics Lab is responsible for the verification of all the tasks of space manipulator of the Chinese free-flight robot space satellite system. We are currently developing the free-flight robot task verification facility (FTVF) through a hardware-in-the-loop way. It consists of a series of simulation and analysis tools to be used for verifying the kinematics (clearance, interface reach, degrees of freedom), dynamics (computed torque, flexibility), visual accessibility (ability to see the work site) and computation power (control period). This paper presents both theoretical and experimental study on the control of a free-flying robot manipulator for space application. The goal of the study is to develop a new control method and hardware-in-the-loop simulation system for target capturing with vision sensor in micro-gravity space environment, considering the dynamical interaction between the space robot and its mobile satellite base. Finally experimental results demonstrate the effect of the simulation system

In this paper, FPGA (field programmable gate array) based hardware architecture for the HIT/DLR hand has been investigated. With the FPGAs for lower level control and DSP (digital signal processor) for higher level control, the whole hardware is very intelligent. By using the high capacity of FPGAs, the additional hardware such as communication controller and PWM generators, can be implemented in a single chip and the hardware system is more flexible and compact. In each finger there is an FPGA for data collection, brushless DC motors control and communication with palm's FPGA by point-to-point serial communication (PPSeCo). The kernel of the hardware system is a PCI-based high speed floating-point DSP for data processing, and FPGA for high-speed (up to 25Mbps) real-time serial communication with the palm's FPGA. There needs only 4 cables for the data transmission and the sampling cycle for each sensor is only 200 /spl mu/s. This paper presents the basic ideas behind the HIT/DLR hand's hard- and software architecture adapted to new needs in data processing.

The paper presents hardware and software architectures of the HIT/DLR Hand. The hand has four identical fingers and an extra degree of freedom (d.o.f) for the palm. In each finger, there is a re-configurable Field Programmable Gate Array (FPGA) for data acquisition, Brushless DC (BLDC) motor control and communication with the palm's FPGA by Point-to-Point Serial Communication (PPSeCo). The kernel of the hardware system is a PCI-based high speed floating-point Digital Signal Processor (DSP) for data processing, and an FPGA for high speed (up to 25 Mbps) real-time serial communication with the palm's FPGA. In order to achieve high modularity and reliability of the hand, a fully mechatronic integration and analog signals in-situ digitalization philosophy are implemented to minimize the dimension, number of the cables (5 cables including power supply) and protect data communication from outside disturbances. Furthermore, according to the hardware architecture of the hand, a hierarchical software architecture has been established to perform all data processing and control of the hand. The software structure provides basic Application Programming Interface (API) functions and skills to access all hardware resources for data acquisition, computation and teleoperation.

This paper presents the current work progress of HIT/DLR Dexterous Hand. Based on the technology of DLR Hand II, HIT and DLR are jointly developing a smaller and easier manufactured robot hand. The prototype of one finger has been successfully built. The finger has three DOF and four joints, the last two joints are mechanically coupled by a rigid linkage. All the actuators are commercial brushless DC motors with integrated analog Hall sensors. DSP based control system is implemented in PCI bus architecture and the serial communication between the hand and DSP needs only 6 lines(4 lines power supply and 2 lines communication interface). The fingertip force can reach 10N.

We prove a new necessary and sufficient condition for 2D three-finger equilibrium grasps and implement a geometrical algorithm for computing force-closure grasps of polygonal objects in this article. The algorithm is quite simple and only needs some algebraic calculations. An easily computable measure of how far a grasp is from losing force-closure is provided as well. Finally, we implement the algorithm and demonstrate its usefulness by an example.

This paper presents a novel passive robot system with 6 DOF force/torque sensor for measuring spacesuit joint damping parameters. Based on its special mechanical structure, a 3 DOF model of flexible IVA (intra vehicular activity) spacesuit joint has been built. Experimental results prove the effectiveness of the measuring principle. Potential application of the measuring system is discussed.