Nikolaus Seitz

The DLR hand arm system

An anthropomorphic hand arm system using variable stiffness actuation has been developed at DLR. It is aimed to reach its human archetype regarding size, weight and performance. The main focus of our development is put on robustness, dynamic performance and dexterity. Therefore, a paradigm change from impedance controlled, but mechanically stiff joints to robots using intrinsic variable compliance joints is carried out.

Multisensory five-finger dexterous hand: The DLR/HIT Hand II

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.

The HIT/DLR dexterous hand: work in progress

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.

FPGA based hardware architecture for HIT/DLR hand

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 palms 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 palms 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 hands hard- and software architecture adapted to new needs in data processing.

High performance DSP/FPGA controller for implementation of HIT/DLR dexterous robot hand

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 palms 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 palms 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.

DLR hand II: hard- and software architecture for information processing

In the robotic community more and more hands have been developed. These newly designed manipulators greatly outperform their ancestors in terms of available sensor signals, applicable grasping force, mechanical stability, reliability, kinematic design and more. This development extends the possible range and complexity of applications of robotic grippers also to areas outside of well structured laboratories and simple tasks. It also calls for more flexible control structures to provide a framework for implementing and executing these newly arising tasks without having to start from scratch for each new task. During the last few years we developed a control system architecture for DLR hand II that proved to be useful for a great variety of different applications. This paper presents the basic ideas behind DLR hand IIs hard- and software architecture adapted to new needs in data processing.

Dexhand: A Space qualified multi-fingered robotic hand

Despite the progress since the first attempts of mankind to explore space, it appears that sending man in space remains challenging. While robotic systems are not yet ready to replace human presence, they provide an excellent support for astronauts during maintenance and hazardous tasks. This paper presents the development of a space qualified multi-fingered robotic hand and highlights the most interesting challenges. The design concept, the mechanical structure, the electronics architecture and the control system are presented throughout this overview paper.

Embedded FPGA-based control of the HIT/DLR hand

In this paper, we developed a performance-enhanced, stand-alone dexterous robot hand with effective mechanical structure and lightweight control hardware. In the context, the paper shows the design methodology of HIT/DLR dexterous robot hand II controller using FPGA (field programmable gate array). Lower level controller is implemented in an FPGA and higher level controller is implemented in a DSP. Instead of a conventional architecture, a FPGA-based soft processor core is utilized. It includes a set of custom peripheral cores, such as data collection, brushless DC motors control and communication with palms FPGA by point-to-point serial communication (PPSeCo). FPGAs make modular fingers more versatile, adding some new features to the design of hand like real-time control, hardware reuse, lower cost, fault-recovering, and software/hardware co-design. Finger control system use the NIOS soft CPU as hardware platform and uC/OS II real-time operating system as software platform to improve the efficiency of the system and short the responding time of a task. The experiment results clearly illustrate the high performance of the control system

An intelligent linear actuator and its control system

This paper presents a very compact multisensory linear actuator and its control system. The key element of this linear actuator system is the DLR patented planetary roller spindle drive (PRSD/sup R/). With a volume of 50/spl times/50/spl times/104 mm (length/spl times/width/spl times/height), it can output more than 100 kg force and achieve a displacement of 50 mm with a resolution of 2 /spl mu/m. A compact microcontroller based stand-alone system enables the actuator to only need 3 cables for the RS232 and 5 cables for the RS422 serial communication with any commercial PC, in addition to 2 cables for the power supply.

Multisensory HIT/DLR dexterous robot hand

This paper describes 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 with multisensory system. The prototype of one finger has been successfully built. The finger has three DOF and four joints; 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 communications between the hand and DSP needs only 2 lines. The fingertip force can reach 10N.