Stefan Jörg

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.

DLR MiroSurge: a versatile system for research in endoscopic telesurgery.

PurposeResearch on surgical robotics demands systems for evaluating scientific approaches. Such systems can be divided into dedicated and versatile systems. Dedicated systems are designed for a single surgical task or technique, whereas versatile systems are designed to be expandable and useful in multiple surgical applications. Versatile systems are often based on industrial robots, though, and because of this, are hardly suitable for close contact with humans.MethodTo achieve a high degree of versatility the Miro robotic surgery platform (MRSP) consists of versatile components, dedicated front–ends towards surgery and configurable interfaces for the surgeon.ResultsThis paper presents MiroSurge, a configuration of the MRSP that allows for bimanual endoscopic telesurgery with force feedback.ConclusionsWhile the components of the MiroSurge system are shown to fulfil the rigid design requirements for robotic telesurgery with force feedback, the system remains versatile, which is supposed to be a key issue for the further development and optimisation.

Flexible robot-assembly using a multi-sensory approach

Recent research in industrial robotics aims at the involvement of additional sensory devices to improve robustness, flexibility and performance of common robot applications. Many different sensors have been developed over the past years to fit the requirements of different but very specific tasks. Special seam tracking sensors support the robot in welding applications. Vision systems are common in quality control and inspection. Force/torque sensors mounted to a robots wrist are still an exception and limited to the fields of scientific research. Compared to the number of annual robot sales the number of sensor equipped robots is still negligible, although the benefits of sensory feedback are obvious. In this paper we introduce a general approach to tackle the problem of sensor-based robot assembly. We realized a flexible assembly cell that includes a variety of different sensors for mating with moving parts.

MICA - A new generation of versatile instruments in robotic surgery

Robotic surgery systems are highly complex and expensive pieces of equipment. Demands for lower cost of care can be met if these systems are employable in a flexible manner for a large variety of procedures. To protect the initial investment the capabilities of a robotic system need to be expandable as new tasks arise.

The DLR MiroSurge - A robotic system for surgery

This video presents the in-house developed DLR MiroSurge robotic system for surgery. As shown, the system is suitable for both minimally invasive and open surgery. Essential part of the system is the MIRO robot: The soft robotics feature enables intuitive interaction with the robot.

Flexible Signal-Oriented Hardware Abstraction for Rapid Prototyping of Robotic Systems

Diffuse and changing specifications for the design of light-weight robots result in high design costs for the desired robotic system, especially the electronic modules and related software drivers. To reduce those costs, we created a flexible robot platform, consisting of FPGA joint modules that are connected by a high speed communication. To fully exploit the hardware flexibility, we introduce a flexible signal-oriented hardware abstraction that is based on a signal flow oriented middleware (SFMiddleware). SFMiddleware enables the transparent integration of changing joint hardware functionality with robot control applications. Utilizing a static system specification approach, we benefit from the abstraction of a middleware without the typical overhead of common middleware implementations. Thus, we achieve a small run-time footprint and control cycles of more than 10 kHz

FPGA based real-time visual servoing

Real-time image processing tasks not only require high computing power but also high data bandwidth. Though current processors excel in computing power, memory throughput is still the bottleneck for stream-oriented applications such as low-level image processing tasks. The alternative of special-purpose systems lacks flexibility at a high design effort and long development time. This effort often becomes void by the rapid advance of mainstream computing technology. FPGA technology promises flexibility and the necessary computing performance at affordable design costs. In this paper, we describe our approach for a prototype image processing system for robot vision applications, based on FPGA technology. We use a commercially available PCl-board to implement a typical application based on the experimental servicing satellite (ESS) scenario.

The computing and communication architecture of the DLR Hand Arm System

The computing and communication architecture of the DLR Hand Arm System is presented. Its task is to operate the robots 52 motors and 430 sensors. Despite that complexity, the main design goal for it is to create a flexible architecture that enables high-performance feedback control with cycles beyond 1kHz. Flexibility is achieved through a hierarchical net of computing nodes that goes from commercial-of-the-shelf hosts down to the physical interfaces of sensors and actuators. The concept of a Hardware Abstraction Layer (HAL) provides a convenient high-level interface to the entire robotic hardware. First experiments with prototypical control applications, featuring 100 kHz and 3 kHz control loops, demonstrate the performance of the architecture.

The Virtual Path: The Domain Model for the Design of the MIRO Surgical Robotic System

Abstract The MIRO Platform, designed at DLR, is a highly integrated and compliant mechatronic robotic system for minimally invasive surgery. This publication presents the “Virtual Path,” a domain model in the sense of Domain Driven Design, which provides a formal guideline for all designers of the MIRO Platform to obtain a deterministic implementation without the necessity of a monolithic framework. Using Hardware-Software Co-Design methods, the roles of the basic component types of a robotic system were formally defined. The result is a set of design idioms that provide a solution for three main issues when mapping those components to a distributed heterogeneous mechatronic architecture: synchronization, scheduling, and error handling.

The Hardware Abstraction Layer — Supporting control design by tackling the complexity of humanoid robot hardware

Humanoid robots are highly integrated robotic systems with many sensors and actuators. The DLR Hand Arm system has 52 motors and 430 sensors. Design goal is to operate the robot with high-performance feedback control at cycles beyond 1kHz but to retain the flexibility of prototyping control algorithms. This is achieved with the concept of a Hardware Abstraction Layer (HAL) that provides a convenient high-level interface to the entire robotic hardware. The requirements for the design of a HAL in terms of functionality and implementation are presented that improve the integration of complex robot hardware with prototype control applications. Experiments with the HAL of the DLR Hand Arm System demonstrate the high performance of a Simulink Interface implementation. A 3 kHz control loop yields a latency below 333/is and a jitter below 50/xs.