ISAACS,P.M.AND COHEN, M.F. 1987. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. In Computer Graphics (Proceedings of SIGGRAPH 87). Annual Conference Series. ACM SIGGRAPH, 215--224.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....and functional methods to the models. The first approach consists of finding new ways of using the existing laws either directly or after simplification for motion control. 1] The major methods include keyframing, 2] functional method, 3] inverse kinematics, 3] direct and inverse dynamics, 4] 5] [6] or optimal control. 7] 8] The second approach corresponds to methods coming from various disciplines. In human animation, recent research includes walking, 9] motion of flexible torso and spine, 10] jumping, 11] ballroom dances, 12] etc. The goal of all these applications is looking for realism ....

....and torques acting on the joint, contrary to a passive object like a pinpointed chain that is only driven by external force and torque during motion. The problem is how to find the time varying forces and torques before using the direct dynamics. There has been some work in this aspect recently. [6] [8] 24] The Spacetime Control in [8] has given an impressive sequence of a dynamic lamp. The method describes a formation of animation as a constrained multipoint boundary value problem, thus allowing the user to specify initial, intermediate and final configurations. The SQR method used to ....

[Article contains additional citation context not shown here]

P.M. Isaacs and M. F. Cohen, Controlling Dynamics Simulation with Kinematic Constraints, Proceedings of Siggraph'87.

....of considerable literature. The main goal is to ease the burden of an animator by shifting the tedious task of detailed motion specification to an automated controller. The abstraction of motion mechanism from different points of views engendered several paradigms of motion control: dynamic models [27,1,12,7,17,19,21,11], inverse kinematics models [10,15,20,5] In dynamic models, forces and torques generating a particular motion are computed where as in inverse kinematics, an end goal is specified and an articulated structure is expected to reach it through an end effector subject to certain kinematic ....

....the other hand inverse kinematics models, owing to kinematic constraints, enable an animator to specify goal directed animation much more easily than in purely dynamic models. There have been combined techniques to overcome such limitations by embedding kinematic constraints within a dynamic model [12,6,14]. State space approaches: Laszlo et al. [16] use a state space by representing limit cycles using a set of Regulation Variables and attaining automatic balancing of articulated figure. Van de Panne et al. [25] use dynamic programming to search state space for appropriate torques at joints to ....

Isaacs, P.M., Cohen, M.F., Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions and Inverse Dynamics, Computer Graphics, 21, 4 (July, 1987), 215-224

....Even though the movements obey physical laws, the computation of the exact amount of forces and torques to apply still remains the key point. Additionally, the same problem as stated above occurs, where a specified goal configuration has to be reached which leads to an inverse dynamics problem [47] which we will not further discuss within this report. Zoran Popovic presented a remarkable work at SIGGRAPH 00 related to that topic: Interactive manipulation of rigid body simulation [86] This work presents a system which enables the user to interactively manipulate a physically based motion ....

P. M. Isaacs and M. F. Cohen. "Controlling dynamic simulation with kinematic constraints. " In Proceedings of the 14th annual conference on Computer graphics and interactive techniques, pages 215--224. ACM Press, 1987.

....choreography, animation, intelligent actors, physically based modeling I. Introduction Improving tools for use by animators has been an important research goal in computer graphics for nearly two decades. Much current work has been done in the areas of inverse kinematics and dynamics [1], 2] physical simulation [3] constraint systems [4] intelligent actors [5] and motion synthesis [6] Nevertheless, very little attention has been paid to the animator s working methodologies. The typical current practice in the computer animation industry is that the animator develops motion ....

P. M. Isaacs and M. F. Cohen, "Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions and Inverse Dynamics ", in Computer Graphics (ACM SIGGRAPH Conference Proceedings), July 1987, vol. 21, pp. 215--224.

....including cyclic movement like walking. Other approaches to combine control and physical simulation have been explored: Wilhelms [24] and Barzel and Barr [3] blend kinematic and dynamic analysis, Moore and Wilhelms [20] and Baraff [2] discuss the collision and contact problems, Isaacs and Cohen [16] incorporate inverse dynamics in their simulation system, and Brotman and Netravali [5] use dynamics and optimal control to interpolate between key frames. Other Work in Walking and Control The algorithmic approach is meant as a general method by which to control complex mechanisms. In this ....

P. M. Isaacs and M. F. Cohen. Controlling dynamic simulation with kinematic constraints, behavior constraints and inverse dynamics. In Computer Graphics (SIGGRAPH 87), pages 215--224. ACM, July

....or by a more complex path. Section 6 explains how to use these temporal constraints for scripting and synchronizing complex motions in a full animation sequence. We conclude and discuss work in progress in Section 7. 2 Related Work Constraints methods [2, 16, 9] and inverse dynamic techniques [12, 6, 16, 17] enable the specification of trajectories for some of the components of a complex structure, while leaving the system to animate the other degrees of freedom. They do not offer any help for improving the realism of the specified motions. In particular automatic collision processing (that would ....

P.M. Isaacs and M.F. Cohen. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. Computer Graphics, 21(4):215--224, July 1987.

....and the angular acceleration. Direct dynamics is the application of these laws which calculate the motion generated by a given force. Conversly, inverse dynamics methods calculate the forces that would generate a given motion. The equations above hold for a single solid. Specic methods [25, 2, 19, 1] have been used to apply these equations to an articulated skeleton, modeled as a hierarchy of rigid solids (namely the limbs) connected by joints. A full description of these methods is beyond the scope of this paper. We brieAEy describe the two basic approaches. The rst method was introduced by ....

....apply these equations to an articulated skeleton, modeled as a hierarchy of rigid solids (namely the limbs) connected by joints. A full description of these methods is beyond the scope of this paper. We brieAEy describe the two basic approaches. The rst method was introduced by Isaacs and Cohen [25] and relies on a Lagrangian formalism. Using generalized coordinates (each limb angular position is expressed in its father s local coordinate system) a igeneralized mass matrixj M can be computed. Computing motion then means solving an INRIA Computer Animation of Human Walking: a Survey 11 ....

P.M. Isaacs and M.F. Cohen. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. In Proceedings of ACM SIGGRAPH, pages 215224. Addison Wesley, July 1987.

....and the articulated structure into the system so that it can execute certain aspects of movement autonomously. This has lead to the development of higher level control schemes [5, 6, 15, 22, 33] where the knowledge is frequently specified in terms of rules, and physically based modeling techniques [8, 12, 18, 30, 31] in which knowledge is embedded in the equations of motion, constraints and possibly an optimization expression. Both approaches often suffer from lack of interactiv 1 School of ComputingScience, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada, armin cs.sfu.ca) 2 Apple Computer, Inc. ....

ISAACS,P.,AND COHEN, M. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. In ComputerGraphics (SIGGRAPH '87 Proceedings) (1987), vol. 21, pp. 215--224.

....solves half the problem. Remaining is how to specify forces and torques which actually move the figure in a way which the animator might desire. 3.3. 2 Inverse Dynamics Isaacs and Cohen described the DYNAMO system which allowed algorithmic and kinematic motion to coexist in a dynamic framework (Isaacs and Cohen, 1987). Some degrees of freedom were specified algorithmically or with key frames, while those not specified this way were subject to the dynamics simulation. Inverse dynamics were used to derive the forces necessary to move end effectors in the way described by the kinematic constraints. Barzel ....

Isaacs, P. M. and Cohen, M. F. (1987). Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. In Stone, M. C., editor, Computer Graphics (SIGGRAPH '87 Proceedings), volume 21, pages 215--224.

....motion NLP Inverse dynamics Figure 1: Comparison of Various Animation Methods In this section we review the major animation techniques for articulated rigid bodies. These methods fall into two categories: those based on forward dynamics [29, 6, 25, 22, 16, 5] and those using inverse dynamics [20, 8, 9, 33, 3, 26, 21]. Sometimes inverse dynamics based methods also need forward dynamics for simulation [20, 26] Optimal control based techniques [2, 19] uses forward dynamics. The Spacetime constraints method[33, 3] and Following Footprints of Reality[21] are based upon inverse dynamics. We can also classify the ....

....discretize continuous time dynamic systems to create nonlinear programming problems. This approach is a variant of the finite difference method for solving two point boundary value problems [33, 3] Inverse dynamics methods have been used to calculate joint torques given kinematic motion planning [20, 8, 9, 26]. Pure inverse dynamic methods typically lack reality because the motion has been pre planned, and we need a special tool which will work as a motion planner. Motion planning becomes difficult, especially when free base motion is involved 2 . Forward dynamic simulation usually gives the best ....

P. Isaacs and M. Cohen. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. Computer Graphics 21, 4, 215--224 (1987).

....1993 ] employs an equation system. Buchanan and de Pennington, 1993 ] illustrates the use of computer algebra. 13 [Ruttkay, 1995] presents an editor based on constraint processing, too. 14 The analysis of the complexity of this method is left for future work. Kondo, 1992] p. 146) Isaacs and Cohen, 1987 ] already propagates along DOFs. Kramer, 1992 ] reviewed also in [ Bouzy, 1993 ] and [ Sacks, 1993 ] allows to reformulate the problem so that the search space is discrete, and it declines to prefer iterative methods because these ones cannot exploit intelligently the case when just a small ....

Paul M. Isaacs and Michael F. Cohen. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. Computer Graphics, 21(4):215--224, 1987. SIGGRAPH '87, Anaheim, California, July 27--31, Proceedings, A publication of ACM SIGGRAPH, acm press, New York, NY, U.S.A.

....of having to always be physical. They Constraint Based Motion Adaptation 4 also suffer from being hard to control, which has lead many to study how to determine what forces and torques must be applied to achieve specified requirements. Methods for this include Inverse Dynamics [AGL85] Wil87][IC87] and dynamic constraints [BB88] Pla92] Almost all constraint based approaches apply constraints to individual instants in time to either compute the needed configurations to meet specified constraints (e.g. inverse kinematics) or required forces to apply at the current instant to meet ....

Paul Isaacs and Michael Cohen. Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions, and Inverse Dynamics. Computer Graphics, 21 (4). Proceedings of SIGGRAPH 87.

....The solution to the initial value problem is the motion. The advantage of this approach is that the resulting motion looks realistic since the motion obeys physical laws. So far, this approach has been used to successfully creat motions of chains, bowling, pool, waves, snakes, automobiles, etc [2, 3, 6, 27, 30, 31, 36, 41, 44, 55, 10, 42]. One problem with the simulation approach is that the user has no control over the motion once the initial conditions are specified. Therefore it is difficult to create motions with some desired goals. For example, one can use dynamic simulation to generate a physically correct rotation motion of ....

Paul M. Isaacs and Michael F. Cohen. Controlling dynamic simulation with kinematic constraints, behavior functions, and inverse dynamics. In Proceedings of SIGGRAPH'87 (Anaheim, California, July 27--31, 1987), pages 215--224. ACM, July 1987. BIBLIOGRAPHY 113

.... the physical simulation of flexible objects [10] Isaacs and Cohen performed the physical simulation of rigid bodies for the special case of linked systems without closed kinematic chains, and emphasized ease of modeling, while using an inverse dynamics formulation to control the models behavior [7]. Barzel and Barr used dynamic constraints together with inverse dynamics to find the constraint forces to do physically based modeling [4] Witkin and Kass introduced the concepts of optimal control and spacetime constraints to computer animation [15] Cohen made these spacetime constraints ....

Isaacs, Paul M., and Michael F. Cohen, "Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions, and Inverse Dynamics, " Computer Graphics, pp. 215-224.

....Object animation in Computer Graphics. Researchers in the field of Computer Graphics have developed the concept of physical model for providing objects with realistic behaviours in animated scenes. Several approaches have been developed for the purpose of animating articulated rigid bodies [8] or deformable objects [16] Among these approaches, the model of CordisAnima [1] which basically represents the physical world using elementary particles and spring connectors is the first system of this type which has been used for solving robotics problems [10] 9] As we will see further down, ....

P.M. Isaacs and M.F. Cohen. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. Computer Graphics (SIGGRAPH'87), 21(4), 1987.

No context found.

ISAACS,P.M.AND COHEN, M.F. 1987. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. In Computer Graphics (Proceedings of SIGGRAPH 87). Annual Conference Series. ACM SIGGRAPH, 215--224.

No context found.

Isaacs, P., and Cohen, M. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. In Computer Graphics (SIGGRAPH '87 Proceedings) (1987), vol. 21, pp. 215--224.

No context found.

Isaacs, P. M., and Cohen, M. F. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. Proceedings of SIGGRAPH'87 (Anaheim, Calif., July 27--31, 1987.

No context found.

Isaacs P.M. and Cohen M.F., "Controlling Dynamic Simulation with Kinematic Constrains, Behavior Functions and Inverse Dynamics", Proceedings of SIGGRAPH'87 (Anaheim, California, July 27-31, 1987). In Computer Graphics 21, 4 (July 1987), 215-224

No context found.

Isaacs P.M. and Cohen M.F., "Controlling Dynamic Simulation with Kinematic Constrains, Behavior Functions and Inverse Dynamics", Proceedings of SIGGRAPH `87, Computer Graphics, 21(4):215-224, July 1987.

No context found.

Isaacs87.P. M. Isaacs and M. F. Cohen, Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions, and Inverse Dynamics, Computer Graphics 21, 4 (July 1987), 215-224.

No context found.

Isaacs PM, Cohen MF (1987) Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions and Inverse Dynamics, Proc. SIGGRAPH'87, Computer Graphics, Vol. 21, No4:215-224

No context found.

Isaacs PM, Cohen MF (1987) Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions and Inverse Dynamics, Proc. SIGGRAPH'87, Computer Graphics, Vol. 21, No4, pp.215-224

No context found.

Paul M. Isaacs and Michael F. Cohen. Controlling dynamic simulation with kinematic constraints, behavior functions and inverse dynamics. In Maureen C. Stone, editor, Computer Graphics (SIGGRAPH '87 Proceedings), volume 21, pages 215--224, July 1987.

No context found.

Isaacs PM, Cohen MF (1987) Controlling Dynamic Simulation with Kinematic Constraints, Behavior Functions and Inverse Dynamics, Proc. SIGGRAPH'87, Computer Graphics, Vol. 21, No4:215-224

First 50 documents

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC