Stanley A. Schneider

Object impedance control for cooperative manipulation: theory and experimental results

The dynamic control module of the Dynamic and Strategic Control of Cooperating Manipulators (DASCCOM) project for aerospace robotics is presented. The cooperative manipulation problem is analyzed from a systems perspective, and the desirable features of a control system for cooperative manipulation are discussed. A control policy is developed that enforces a controlled impedance not of the individual arm endpoints, but of the manipulated object itself. A parallel implementation for a multiprocessor system is presented. The controller fully compensates for the system dynamics and directly controls the object internal forces. Most importantly, it presents a simple, powerful, intuitive interface to higher level strategic control modules. Experimental results from a dual two-link-arm robotic system show the effectiveness of the object impedance controller compared to other strategies, both for free-motion slews and environmental contact. >

ControlShell: A Software Architecture for Complex Electromechanical Systems

Real-time system software is notoriously complex. Large projects must balance the special needs of real-time software—such as clock management, control systems, and strategy—with the needs of in teracting teams of programmers, managers, and long-term main tenance personnel. Successful projects require a solid software architecture, an intuitive graphical programming paradigm, a well- developed reuse system, and powerful system services. This paper walks through the methodology and application of ControlShell, the component-based real-time programming system. ControlShell provides an integrated development environment for building complex electromechanical systems. It targets complex systems that require both cyclic data processing and strategic event management and sequencing. ControlShell is specifically designed to facilitate team develop ment of complex electromechanical systems. Teams must share and reuse code; ControlShell provides component-level code shar ing and reuse. Complex systems require flexibility; ControlShell gains flexibility by supporting independent module-level code gen eration. Large systems are most easily designed as independent parts; ControlShell encourages easy interconnectivity of objects. Finally, complex systems are modal; ControlShellfeatures a unique configuration-control system for changing operating modes. The paper concludes by examining the application of this frame work to a dual-arm robotic work cell, a subsystem of the Space Shuttle Launch Processing System, and an underwater autonomous vehicle.

The ControlShell component-based real-time programming system

Real-time system software is notoriously hard to share and reuse. This paper walks through the methodology and application of ControlShell, a component-based programming system real-time system software development. ControlShell combines graphical system-building tools, an execution-time configuration manager, a real-time matrix package, and an object name service into an integrated development environment. It targets complex systems that require on-line reconfiguration and strategic control. ControlShell takes advantage of functional object hierarchies to enable code sharing and reuse. It gains flexibility by supporting easy interconnectivity of these objects. It features a unique configuration control system for changing operating modes. The paper concludes by examining the application of this framework to a dual-arm robotic workcell that is able to pick objects from a moving conveyor and perform simple assemblies,.

System design and interfaces for intelligent manufacturing workcell

This paper introduces a design technique for complex robotic systems called interfaces-first design. Interfaces-first design develops information interfaces based on the characteristics of information flow in the system, and then builds subsystem interfaces from combinations of these information interfaces. This technique is applied to a dual-arm workcell combining a graphical user interface, an on-line motion planner, real-time vision, and an on-line simulator. The system is capable of performing object acquisition from a moving conveyor belt and carrying out simple assemblies, without the benefit of pre-planned schedules nor mechanical fixturing. The information characteristics of this system are analyzed, and divided into three interfaces: world state, task command, and motion commands. Detailed descriptions of the resulting interfaces are provided. The paper concludes with experimental results from the workcell. Both single-arm and dual-arm actions are discussed.

Experimental Integration of Planning in a Distributed Control System

This paper describes a complete system architecture integrating planning into a two-armed robotic workcell. The system is comprised of four major components: user interface, planner, the dual-arm robot control and sensor system, and an on-line simulator.

ControlShell: component-based real-time programming

Real-time system software is notoriously hard to share and reuse. The paper walks through the methodology and application of ControlShell, a component-based programming system real-time system software development. ControlShell combines graphical system-building tools, an execution-time configuration manager, a real-time matrix package, and an object name service into an integrated development environment. It targets complex systems that require on-line reconfiguration and strategic control. ControlShell takes advantage of functional object hierarchies to enable code sharing and reuse. It gains flexibility by supporting easy interconnectivity of these objects. It features a unique configuration control system for changing operating modes.