Alfred Rizzi - Academia.edu (original) (raw)

Papers by Alfred Rizzi

Research paper thumbnail of Toward A Systems Theory for the Composition of Dynamically Dexterous Robot Behaviors

Robotics Research, 1996

We report on our efforts to develop robot controller composition techniques in the context of dex... more We report on our efforts to develop robot controller composition techniques in the context of dexterous "batting" maneuvers. A robot with a flat paddle is required to strike repeatedly at a falling ball until it is brought to zero velocity at a a specified position. The robot's workspace is cluttered with obstacles that disconnect the freespace formed when the ball and paddle remain in contact -the machine is forced to "let go" for a time in order to bring the ball to the desired state. The controller compositions that we create will guarantee that a ball introduced in the "safe workspace" remains there and is ultimately brought to the goal. We believe that the developing systems discipline described here may be extended to build a variety of useful dexterous machines that are similarly single-minded in their pursuit of the user's goal behavior and ability to surmount unanticipated perturbations along the way.

Research paper thumbnail of Physically Variable Compliance in Running

Summary. This paper explores the role and utility of variable compliance in run- ning behaviors. ... more Summary. This paper explores the role and utility of variable compliance in run- ning behaviors. While it is well understood in the literature that leg compliance plays an important role in running locomotion, our conjecture is that mechanically adjustable leg compliance improves the e-ciency and robustness of a running sys- tem. We claim that variable compliance can serve as an

Research paper thumbnail of An Actuator with Mechanically Adjustable Series Compliance

Running is a complex dynamic,task which places strict requirements on both the physical component... more Running is a complex dynamic,task which places strict requirements on both the physical components,and software control systems of a robot. This report explores some of thos e requirements and in particular explores how a variable compliance,actuation system can satisfy many,of them. We present the mechanical,design and software control of such an actuator system. We analyze its performance,through simulation and

Research paper thumbnail of Environmentally Sealed Combustion Powered Linear Actuator

Research paper thumbnail of Progress in spatial robot juggling

Icra, 1993

We review our progress to date in eliciting dynamically dexterous behaviors from a three degree o... more We review our progress to date in eliciting dynamically dexterous behaviors from a three degree of freedom direct drive robot manipulator whose real-time stereo cameras provide 60 Hz sampled images of multiple freely falling bodies in highly structured lighting conditions. At present, the robot is capable of forcing a single ping-pong ball into a specified steady state (near) periodic vertical motion by repeated controlled impacts with a rigid paddle. The robot sustains the steady state behavior over long periods (typically thousands and thousands of impacts) and is capable of recovering from significant unexpected adversarial perturbations of the ball's flight phase. Gain tuning experiments corroborate our contention that the stability mechanism underlying the robot's reliability can be attributed to the same nonlinear dynamics responsible for analogous behavior in a one degree of freedom forebear. We are presently extending an algorithm for simultaneously juggling two bodies developed in that earlier work to the three dimensional case.

Research paper thumbnail of A Rizzi. An actuator with mechanically adjustable series compliance

Research paper thumbnail of Exact Cellular Decompositions in Terms of Critical Points of Morse Functions for Sensor-based Coverage Tasks

Ijrr, 2002

... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, le... more ... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, let 11s introduce 3s: to be the jth connected component of FSx. Now, FS = uxuj.FSi. Consider the space X = .FS\(U, Uj FS;) for all FSi that contain a crit-ical point. ...

Research paper thumbnail of Preliminary Experiments in Robot Juggling: Transputer Based Real-Time Motion Control

In a continuing program of research in robotic control of intermittent dynamical tasks, we have c... more In a continuing program of research in robotic control of intermittent dynamical tasks, we have constructed a three degree of freedom robot capable of "juggling" a ball freely in the earth's gravitational field. This work is a direct extension of that previously reported in [5, 1, 4, 3, 2, 7].

Research paper thumbnail of Dynamic Ambiguities in Frictional Rigid-body Systems with Application to Climbing via Bracing

Proceedings of the 2005 Ieee International Conference on Robotics and Automation, 2005

ó Constructing climbing behaviors for hyper- redundant robots that account for the system dynamic... more ó Constructing climbing behaviors for hyper- redundant robots that account for the system dynamics requires a model of robot dynamics under contact and fric- tion. One common model, rigid-body dynamics with coulomb friction, unfortunately is both an ambiguous and inconsistent set of dynamic axioms. This paper addresses the ambiguity problem by developing an algorithm which computes the set of joint

Research paper thumbnail of Hierarchical Segmentation of Surfaces Embedded in R3 for Auto-Body Painting

Proceedings of the 2005 Ieee International Conference on Robotics and Automation, 2005

Robots are widely used for spray-painting in the automotive industry. Owing to a lack of fully au... more Robots are widely used for spray-painting in the automotive industry. Owing to a lack of fully automated trajectory gen-eration tools, paint specialists often require 3 to 5 months to produce the coverage trajectories for a new automobile model. This programming time is a critical ...

Research paper thumbnail of Exact cellular decompositions in terms of critical points of Morse functions

Proceedings 2000 Icra Millennium Conference Ieee International Conference on Robotics and Automation Symposia Proceedings, Feb 1, 2000

... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, le... more ... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, let 11s introduce 3s: to be the jth connected component of FSx. Now, FS = uxuj.FSi. Consider the space X = .FS\(U, Uj FS;) for all FSi that contain a crit-ical point. ...

Research paper thumbnail of Toward optimal coverage of 2-dimensional surfaces embedded in IR : Choice of start curve

Abstractó For automated spray painting robots, the choice of a start curve from,which all subsequ... more Abstractó For automated spray painting robots, the choice of a start curve from,which all subsequent paths will be determined, plays a critical role in ensuring uniform coverage of the target surface. In this paper, we ultimately propose a method to determine the start curve for two different procedures of coverage path construction. For the rst procedure, we average the target

Research paper thumbnail of A Dynamical Sensor for Robot Juggling

We discuss the sensory management strategy that has evolved over the course of our efforts to bui... more We discuss the sensory management strategy that has evolved over the course of our efforts to build a three degree of freedom robot capable of juggling two balls at once . A field rate stereo camera system passes estimates of the balls' positions to a juggling algorithm that drives the robot's joint actuators. In order to meet the stringent real-time constraints imposed by such a visual servoing task, we have found it necessary to pay increasingly careful attention to our strategy for controlling the dynamics of the camera window management system. The paper concludes with an initial attempt to formalize this control problem.

Research paper thumbnail of Toward the control of attention in a dynamically dexterous robot

Proceedings of 1993 Ieee Rsj International Conference on Intelligent Robots and Systems, Jul 26, 1993

Toward the control of attention in a dynamically dexterous robot", . July 1993.

Research paper thumbnail of Deposition Modeling for Paint Application on Surfaces Embedded in for use in Automated Trajectory

Research paper thumbnail of Development of deposition models for paint application on surfaces embedded in /spl Ropf//sup 3/ for use in automated path planning

Ieee Rsj International Conference on Intelligent Robots and Systems, Dec 4, 2002

As part of an ongoing collaborative effort with the Ford Motor Company, our research aims to deve... more As part of an ongoing collaborative effort with the Ford Motor Company, our research aims to develop practical and efficient trajectory planning tools for automotive painting. This paper documents our efforts to develop analytic deposition models for electrostatic rotating bell (ESRB) atomizers, which have recently become widely used in the automotive painting industry. Conventional deposition models, used in earlier automatic trajectory planning tools, fail to capture the complexity of deposition patterns generated by ESRB atomizers. The models presented here take into account both the surface curvature and the deposition pattern of ESRB atomizers, enabling planning tools to optimize trajectories to meet several measures of quality, such as coating uniformity. In addition to the development of our models, we present experimental results used to evaluate our models, and verify the interaction between the deposition pattern, trajectory, and surface curvature.

Research paper thumbnail of Uniform Coverage of Simple Surfaces

Research paper thumbnail of Preliminary Experiments in Spatial Robot Juggling

The 2nd International Symposium on Experimental Robotics Ii, 1991

Research paper thumbnail of Hierarchical Segmentation of Piecewise Pseudoextruded Surfaces for Uniform Coverage

Ieee Transactions on Automation Science and Engineering, 2009

Complete automation of trajectory planning tools for material deposition/removal applications has... more Complete automation of trajectory planning tools for material deposition/removal applications has become increasingly necessary to reduce the "concept-to-consumer" timeline for rapid product introduction in industries such as the automotive industry. The work in this paper is specifically motivated by automotive spray painting. Prior developments in automated trajectory planning tools promise to reduce the time required to program the robots; however, these approaches are limited to surfaces that are either approximately planar or topologically simple (i.e., with no holes). To extend the applicability of these planning tools to nonplanar and topologically complex surfaces, currently the user has to manually segment a complex surface into simpler subsets, i.e., subsets that are approximately extruded surfaces and contain no holes. However, the complex nature of the relationships between surface segmentation and resulting output characteristics such as material deposition uniformity, process cycle time, and material waste makes the task of manually segmenting the surface difficult. In this paper, we develop a hierarchical procedure that automatically segments a surface based on surface geometry, surface topology, and path geometry to obtain topologically simple subsets that are approximately extruded surfaces. Finally, we compare the effectiveness of our segmentation with the state of the art on a few automotive surfaces in simulation.

Research paper thumbnail of Urban Hopper : SPIE Conference briefing

Research paper thumbnail of Toward A Systems Theory for the Composition of Dynamically Dexterous Robot Behaviors

Robotics Research, 1996

We report on our efforts to develop robot controller composition techniques in the context of dex... more We report on our efforts to develop robot controller composition techniques in the context of dexterous "batting" maneuvers. A robot with a flat paddle is required to strike repeatedly at a falling ball until it is brought to zero velocity at a a specified position. The robot's workspace is cluttered with obstacles that disconnect the freespace formed when the ball and paddle remain in contact -the machine is forced to "let go" for a time in order to bring the ball to the desired state. The controller compositions that we create will guarantee that a ball introduced in the "safe workspace" remains there and is ultimately brought to the goal. We believe that the developing systems discipline described here may be extended to build a variety of useful dexterous machines that are similarly single-minded in their pursuit of the user's goal behavior and ability to surmount unanticipated perturbations along the way.

Research paper thumbnail of Physically Variable Compliance in Running

Summary. This paper explores the role and utility of variable compliance in run- ning behaviors. ... more Summary. This paper explores the role and utility of variable compliance in run- ning behaviors. While it is well understood in the literature that leg compliance plays an important role in running locomotion, our conjecture is that mechanically adjustable leg compliance improves the e-ciency and robustness of a running sys- tem. We claim that variable compliance can serve as an

Research paper thumbnail of An Actuator with Mechanically Adjustable Series Compliance

Running is a complex dynamic,task which places strict requirements on both the physical component... more Running is a complex dynamic,task which places strict requirements on both the physical components,and software control systems of a robot. This report explores some of thos e requirements and in particular explores how a variable compliance,actuation system can satisfy many,of them. We present the mechanical,design and software control of such an actuator system. We analyze its performance,through simulation and

Research paper thumbnail of Environmentally Sealed Combustion Powered Linear Actuator

Research paper thumbnail of Progress in spatial robot juggling

Icra, 1993

We review our progress to date in eliciting dynamically dexterous behaviors from a three degree o... more We review our progress to date in eliciting dynamically dexterous behaviors from a three degree of freedom direct drive robot manipulator whose real-time stereo cameras provide 60 Hz sampled images of multiple freely falling bodies in highly structured lighting conditions. At present, the robot is capable of forcing a single ping-pong ball into a specified steady state (near) periodic vertical motion by repeated controlled impacts with a rigid paddle. The robot sustains the steady state behavior over long periods (typically thousands and thousands of impacts) and is capable of recovering from significant unexpected adversarial perturbations of the ball's flight phase. Gain tuning experiments corroborate our contention that the stability mechanism underlying the robot's reliability can be attributed to the same nonlinear dynamics responsible for analogous behavior in a one degree of freedom forebear. We are presently extending an algorithm for simultaneously juggling two bodies developed in that earlier work to the three dimensional case.

Research paper thumbnail of A Rizzi. An actuator with mechanically adjustable series compliance

Research paper thumbnail of Exact Cellular Decompositions in Terms of Critical Points of Morse Functions for Sensor-based Coverage Tasks

Ijrr, 2002

... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, le... more ... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, let 11s introduce 3s: to be the jth connected component of FSx. Now, FS = uxuj.FSi. Consider the space X = .FS\(U, Uj FS;) for all FSi that contain a crit-ical point. ...

Research paper thumbnail of Preliminary Experiments in Robot Juggling: Transputer Based Real-Time Motion Control

In a continuing program of research in robotic control of intermittent dynamical tasks, we have c... more In a continuing program of research in robotic control of intermittent dynamical tasks, we have constructed a three degree of freedom robot capable of "juggling" a ball freely in the earth's gravitational field. This work is a direct extension of that previously reported in [5, 1, 4, 3, 2, 7].

Research paper thumbnail of Dynamic Ambiguities in Frictional Rigid-body Systems with Application to Climbing via Bracing

Proceedings of the 2005 Ieee International Conference on Robotics and Automation, 2005

ó Constructing climbing behaviors for hyper- redundant robots that account for the system dynamic... more ó Constructing climbing behaviors for hyper- redundant robots that account for the system dynamics requires a model of robot dynamics under contact and fric- tion. One common model, rigid-body dynamics with coulomb friction, unfortunately is both an ambiguous and inconsistent set of dynamic axioms. This paper addresses the ambiguity problem by developing an algorithm which computes the set of joint

Research paper thumbnail of Hierarchical Segmentation of Surfaces Embedded in R3 for Auto-Body Painting

Proceedings of the 2005 Ieee International Conference on Robotics and Automation, 2005

Robots are widely used for spray-painting in the automotive industry. Owing to a lack of fully au... more Robots are widely used for spray-painting in the automotive industry. Owing to a lack of fully automated trajectory gen-eration tools, paint specialists often require 3 to 5 months to produce the coverage trajectories for a new automobile model. This programming time is a critical ...

Research paper thumbnail of Exact cellular decompositions in terms of critical points of Morse functions

Proceedings 2000 Icra Millennium Conference Ieee International Conference on Robotics and Automation Symposia Proceedings, Feb 1, 2000

... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, le... more ... Before we define cellular decomposi-tions in terms of .critical points of Morse functions, let 11s introduce 3s: to be the jth connected component of FSx. Now, FS = uxuj.FSi. Consider the space X = .FS\(U, Uj FS;) for all FSi that contain a crit-ical point. ...

Research paper thumbnail of Toward optimal coverage of 2-dimensional surfaces embedded in IR : Choice of start curve

Abstractó For automated spray painting robots, the choice of a start curve from,which all subsequ... more Abstractó For automated spray painting robots, the choice of a start curve from,which all subsequent paths will be determined, plays a critical role in ensuring uniform coverage of the target surface. In this paper, we ultimately propose a method to determine the start curve for two different procedures of coverage path construction. For the rst procedure, we average the target

Research paper thumbnail of A Dynamical Sensor for Robot Juggling

We discuss the sensory management strategy that has evolved over the course of our efforts to bui... more We discuss the sensory management strategy that has evolved over the course of our efforts to build a three degree of freedom robot capable of juggling two balls at once . A field rate stereo camera system passes estimates of the balls' positions to a juggling algorithm that drives the robot's joint actuators. In order to meet the stringent real-time constraints imposed by such a visual servoing task, we have found it necessary to pay increasingly careful attention to our strategy for controlling the dynamics of the camera window management system. The paper concludes with an initial attempt to formalize this control problem.

Research paper thumbnail of Toward the control of attention in a dynamically dexterous robot

Proceedings of 1993 Ieee Rsj International Conference on Intelligent Robots and Systems, Jul 26, 1993

Toward the control of attention in a dynamically dexterous robot", . July 1993.

Research paper thumbnail of Deposition Modeling for Paint Application on Surfaces Embedded in for use in Automated Trajectory

Research paper thumbnail of Development of deposition models for paint application on surfaces embedded in /spl Ropf//sup 3/ for use in automated path planning

Ieee Rsj International Conference on Intelligent Robots and Systems, Dec 4, 2002

As part of an ongoing collaborative effort with the Ford Motor Company, our research aims to deve... more As part of an ongoing collaborative effort with the Ford Motor Company, our research aims to develop practical and efficient trajectory planning tools for automotive painting. This paper documents our efforts to develop analytic deposition models for electrostatic rotating bell (ESRB) atomizers, which have recently become widely used in the automotive painting industry. Conventional deposition models, used in earlier automatic trajectory planning tools, fail to capture the complexity of deposition patterns generated by ESRB atomizers. The models presented here take into account both the surface curvature and the deposition pattern of ESRB atomizers, enabling planning tools to optimize trajectories to meet several measures of quality, such as coating uniformity. In addition to the development of our models, we present experimental results used to evaluate our models, and verify the interaction between the deposition pattern, trajectory, and surface curvature.

Research paper thumbnail of Uniform Coverage of Simple Surfaces

Research paper thumbnail of Preliminary Experiments in Spatial Robot Juggling

The 2nd International Symposium on Experimental Robotics Ii, 1991

Research paper thumbnail of Hierarchical Segmentation of Piecewise Pseudoextruded Surfaces for Uniform Coverage

Ieee Transactions on Automation Science and Engineering, 2009

Complete automation of trajectory planning tools for material deposition/removal applications has... more Complete automation of trajectory planning tools for material deposition/removal applications has become increasingly necessary to reduce the "concept-to-consumer" timeline for rapid product introduction in industries such as the automotive industry. The work in this paper is specifically motivated by automotive spray painting. Prior developments in automated trajectory planning tools promise to reduce the time required to program the robots; however, these approaches are limited to surfaces that are either approximately planar or topologically simple (i.e., with no holes). To extend the applicability of these planning tools to nonplanar and topologically complex surfaces, currently the user has to manually segment a complex surface into simpler subsets, i.e., subsets that are approximately extruded surfaces and contain no holes. However, the complex nature of the relationships between surface segmentation and resulting output characteristics such as material deposition uniformity, process cycle time, and material waste makes the task of manually segmenting the surface difficult. In this paper, we develop a hierarchical procedure that automatically segments a surface based on surface geometry, surface topology, and path geometry to obtain topologically simple subsets that are approximately extruded surfaces. Finally, we compare the effectiveness of our segmentation with the state of the art on a few automotive surfaces in simulation.

Research paper thumbnail of Urban Hopper : SPIE Conference briefing