The technological developments in distributed systems have led to new telerobotic applications, such as virtual laboratories and remote maintenance of complex equipment. These applications must satisfy both the general requirements of distributed computing, e.g. location transparency and interoperability, and the domain-specific requirements of reconfigurability, guaranteed performance, real-time operation, and cooperation among robots and sensory systems. In this paper, we describe a software framework for distributed telerobotic systems exploiting advanced CORBA features, including Asynchronous Method Invocation and real-time priorities. The framework allows development of portable multithreaded client-server applications supporting concurrent and preemptable actions in the target robot system, and has been evaluated in a laboratory setup including a robot manipulator and two cameras accessible by multiple clients

No abstract

Distributed telerobotic applications exploiting Internet-related technologies, such as virtual laboratories and on-line robots, require effective techniques for timely delivery of sensory data to remote clients. In these systems, there is a need to distribute increasing quantities of sensory data to a potentially large number of clients during system operation. In this paper, we describe and evaluate three implementations of a sensory data distribution subsystem in the context of a CORBA-based framework for telerobotic applications. Experimental results show that solutions exploiting CORBA services and based on the event channel paradigm represent a viable alternative to ad-hoc solutions. The overhead associated to CORBA services becomes less significant with larger message size. Moreover, these services ensure portability, extensibility, reduction in programming complexity, and improved scalability when the number of clients increases

A new class of telerobotic applications is making its way into research laboratories, fine arts or science museums, and industrial installations. Virtual laboratories and remote equipment maintenance are examples of these applications, which are built exploiting distributed computing systems and Internet technologies. Distributed computing technologies provide several advantages to telerobotic applications, such as dynamic and multiuser access to remote resources and arbitrary user locations. Nonetheless, building these applications remains a substantial endeavor, especially when performance requirements must be met. The aim of this paper is to investigate how mainstream and advanced features of the CORBA object-oriented middleware can be put to work to meet the requirements of novel telerobotic applications. We show that Real-Time CORBA extensions and asynchronous method invocation of CORBA services can be relied upon to meet performance and functional requirements, thereby enabling teleoperation on local area networks. Furthermore, CORBA services for concurrency control and large-scale data distribution enable geographic-scale access for robot teleprogramming. Limitations in the currently available implementations of the CORBA standard are also discussed, along with their implications. The effectiveness and suitability for telerobotic applications of several CORBA mechanisms are tested first individually and then by means of a software framework exploiting CORBA services and ensuring component-based development, software reuse, low development cost, fully portable real-time and communication support. A comprehensive telerobotic application built based on the framework is described in the paper and evaluated on both local and wide area networks. The application includes a robot manipulator and several sensory subsystems under concurrent access by multiple competing or collaborating operators, one of which is equipped with a multimodal user interface acting as the master device