This paper describes algorithms for the animation of men and women performing three dynamic athletic behaviors: running, bicycling, and vaulting. We animate these behaviors using control algorithms that cause a physically realistic model to perform the desired maneuver. For example, control algorithms allow the simulated humans to maintain balance while moving their arms, to run or bicycle at a variety of speeds, and to perform a handspring vault. Algorithms for group behaviors allow a number of simulated bicyclists to ride as a group while avoiding simple patterns of obstacles. We add secondarymotion to the animations with springmass simulations of clothing driven by the rigid-body motion of the simulated human. For each simulation, we compare the computed motion to that of humans performing similar maneuvers both qualitatively through the comparison of real and simulated video images and quantitatively through the comparison of simulated and biomechanical data.

In order to build autonomous robots that can carry out useful work in unstructured environments new approaches have been developed to building intelligent systems. The relationship to traditional academic robotics and traditional artificial intelligence is examined. In the new approaches a tight coupling of sensing to action produces architectures for intelligence that are networks of simple computational elements which are quite broad, but not very deep. Recent work within this approach has demonstrated the use of representations, expectations, plans, goals, and learning, but without resorting to the traditional uses, of central, abstractly manipulable or symbolic representations. Perception within these systems is often an active process, and the dynamics

In this paper, we describe the design and control of RHex, a power autonomous, untethered, compliant-legged hexapod robot. RHex has only six actuators — one motor located at each hip — achieving mechanical simplicity that promotes reliable and robust operation in real-world tasks. Empirically stable and highly maneuverable locomotion arises from a very simple clock-driven, open-loop tripod gait. The legs rotate full circle, thereby preventing the common problem of toe stubbing in the protraction (swing) phase. An extensive suite of experimental results documents the robot’s significant ”intrinsic mobility ” — the traversal of rugged, broken and obstacle ridden ground without any terrain sensing or actively controlled adaptation. RHex achieves fast and robust forward locomotion traveling at speeds up to one body length per second and traversing height variations well exceeding its body clearance.

An ambitious goal in the area of physics-based computer animation is the creation of virtual actors that autonomously synthesize realistic human motions and possess a broad repertoire of lifelike motor skills. To this end, the control of dynamic, anthropomorphic figures subject to gravity and contact forces remains a difficult open problem. We propose a framework for composing controllers in order to enhance the motor abilities of such figures. A key contribution of our composition framework is an explicit model of the "pre-conditions" under which motor controllers are expected to function properly. We demonstrate controller composition with pre-conditions determined not only manually, but also automatically based on Support Vector Machine (SVM) learning theory. We evaluate our composition framework using a family of controllers capable of synthesizing basic actions such as balance, protective stepping when balance is disturbed, protective arm reactions when falling, and multiple ways of standing up after a fall. We furthermore demonstrate these basic controllers working in conjunction with more dynamic motor skills within a prototype virtual stuntperson. Our composition framework promises to enable the community of physics-based animation practitioners to easily exchange motor controllers and integrate them into dynamic characters.

Building on principles from our prior work on procedural texture synthesis, we are able to create remarkably lifelike, responsively animated characters in real time. Rhythmic and stochastic noise functions are used to de ne time varying parameters that drive computer generated puppets. Because we are conveying just the \texture " of motion, we are able to avoid computation of dynamics and constraint solvers. The subjective impression of dynamics and other subtle in uences on motion can be conveyed with great visual realism by properly tuned expressions containing pseudorandom noise functions. For example, we can make acharacter appear to be dynamically balancing herself, to appear nervous, or to be gesturing in a particular way. Each move has an internal rhythm, and transitions between moves are temporally constrained so that \impossible " transitions are precluded. For example, if while the character is walking we specify a dance turn, the character will always step into the turn onto the correct weight-bearing foot. An operator can makeacharacter perform a properly connected sequence of actions, while conveying particular moods and attitudes, merely by pushing buttons at a high level. Potential uses of such high level \textural " approaches to computer graphic simulation include Role Playing Games, simulated conferences, \clip animation", graphical front ends for MUDs (Ste92) (Ger92), and synthetic performances.

This paper describes our current research into nonprehensile palm manipulation. The term “palm ” refers to the use of the entire device surface during manipulation, as opposed to use of the fingertips alone.

Seemingly simple behaviors such as human walking are difficult to model because of their inherent instability. Kinematic animation techniques can freely ignore such intrinsically dynamic problems, but they therefore also miss modeling important motion characteristics. On the other hand, the effect of balancing can emerge in a physically-based animation, but it requires computing delicate control strategies. We propose an alternative method that adds closedloop feedback to open-loop periodic motions. We then apply our technique to create robust walking gaits for a fully-dynamic 19 degree -of-freedom human model. Important global characteristics such as direction, speed and stride rate can be controlled by changing the open-loop behavior alone or through simple control parameters, while continuing to employ the same local stabilization technique. Among other features, our dynamic "human" walking character is thus able to follow desired paths specified by the animator. Keywords: control...

Birds, fish, and many other animals travel as a flock, school, or herd. Animals in these groups must remain in close proximity while avoiding collisions with neighbors and with obstacles. We would like to reproduce this behavior for groups of artificial creatures with significant dynamics. In this paper we describe an algorithm for creatures that move as a group and evaluate the performance of the algorithm with three simulated systems: legged robots, human-like bicycle riders, and point-mass systems. Both the legged robots and the bicyclists are dynamic simulations that must control balance, facing direction, and forward speed as well as movement with the group. The point-mass systems have minimal dynamics and are included to facilitate our understanding of the effects of the dynamics on the performance of the algorithms. Introduction To run as a group, animals must remain in close proximity while changing direction and velocity and avoiding collisions with other group members and o...

. Robotic locomotion is based in a variety of instances upon cyclic changes in the shape of a robot mechanism. Certain variations in shape exploit the constrained nature of a robot's interaction with its environment to generate net motion. This is true for legged robots, snakelike robots, and wheeled mobile robots undertaking maneuvers such as parallel parking. In this paper we explore the use of tools from differential geometry to model and analyze this class of locomotion mechanisms in a unified way. In particular, we describe locomotion in terms of the geometric phase associated with a connection on a principal bundle, and address issues such as controllability and choice of gait. We also provide an introduction to the basic mathematical concepts which we require and apply the theory to numerous example systems. 1. Introduction The term "locomotion" refers to autonomous movement from place to place. Robotic locomotion employs a variety of mechanisms. Though most of today's mobile r...

Construction toys are a superb medium for creating geometric models. We argue that such toys, suitably instrumented or sensed, could be the inspiration for a new generation of easy-to-use, tangible modeling systems---especially if the tangible modeling is combined with graphical-interpretation techniques for enhancing nascent models automatically. The three key technologies needed to realize this idea are embedded computation, vision-based acquisition, and graphical interpretation. We sample these technologies in the context of two novel modeling systems: physical building blocks that self-describe, interpret, and decorate the structures into which they are assembled; and a system for scanning, interpreting, and animating clay figures. In Proceedings of SIGGRAPH 2000, July 23-28, 2000. New Orleans, Louisiana, USA. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted ...