Showing papers by "Dale Lawrence published in 1994"
08 May 1994
TL;DR: A representative dynamic model is used to develop expressions for the limits on closed loop hand controller impedance, and implications of these trade-offs in designing "ideal-equivalent" hand controllers are discussed.
Abstract: Realistic specifications are developed for hand controller mechanical and control design, based on limitations of human operator motion and perception capabilities observed in initial experimental studies. A representative dynamic model is used to develop expressions for the limits on closed loop hand controller impedance. Specific trade-offs are derived between mechanical design options and control design options for achieving realistic performance specifications. Implications of these trade-offs in designing "ideal-equivalent" hand controllers are discussed, and applied to a high-performance laboratory hand controller prototype. >
75 citations
29 Jun 1994
TL;DR: In this paper, a control technique for small satellites is presented which offers reduced mass, power, and volume over conventional attitude control methods, and is specialized to match the unique dynamics models for spacecraft as well as the specific disturbance environment satellites encounter in low earth orbit.
Abstract: A control technique for small satellites is presented which offers reduced mass, power, and volume over conventional attitude control methods. Learning control methods common in the robotics literature are specialized to match the unique dynamics models for spacecraft as well as the specific disturbance environment satellites encounter in low earth orbit.
6 citations
TL;DR: In this article, an architecture-independent analysis approach is described for evaluation of control systems designed to provide compliant manipulator/task interaction, and two issues are highlighted: a new safety bound which provides an explicit, quantitative design objective; and an examination of typical task dynamics and their impact on the difficulty of control design.
Abstract: An architecture-independent analysis approach is described for evaluation of control systems designed to provide compliant manipulator/task interaction. Two issues are highlighted: a new safety bound which provides an explicit, quantitative design objective; and an examination of typical task dynamics and their impact on the difficulty (complexity) of control design. Two examples of control design within this framework are presented, demonstrating the need to consider safety bounds of the type proposed. >
3 citations
TL;DR: The proposed method is based on the evaluation of possible burstings in the adaptive loop and its simplicity and effectiveness is demonstrated by analyzing global stability and performance of the discrete-time direct adaptive controller.
Abstract: In this note, a new technique is proposed for the global stability analysis of adaptive control of time-varying systems. The proposed method is based on the evaluation of possible burstings in the adaptive loop. Its simplicity and effectiveness is demonstrated by analyzing global stability and performance of the discrete-time direct adaptive controller. The developed technique reflects physical phenomena inside the adaptive loop, i.e., possible occurrence of instabilities and burstings. Precise upper bounds on the admissible speed of the parameter variations and on all the signals are established in terms of clearly defined physical quantities. >
1 citations
29 Jun 1994
TL;DR: In this article, an exact linear time-invariant analysis of a simple adaptive filter for the cancellation of single tone disturbances is carried out and limits on adaptive tracking speed are discussed.
Abstract: Exact linear time-invariant analysis of a simple adaptive filter for the cancellation of single tone disturbances is carried out. Symmetry in the multivariable loop gain is exploited to simplify control design. Limits on adaptive tracking speed are discussed.
TL;DR: H1 and H*** safety bounds are introduced for evaluation of compliance control designs deriving from any control architecture or design method and examples are presented to demonstrate the use of these bounds and the need to consider safety bounds of the type proposed.
Abstract: Safe manipulator/task interaction is defined and quantified based on interaction forces resulting from manipulator motion commands. H1 and H*** safety bounds are introduced for evaluation of compliance control designs deriving from any control architecture or design method. Compliance control design examples are presented to demonstrate the use of these bounds, and to demonstrate the need to consider safety bounds of the type proposed. © 1994 John Wiley & Sons, Inc.