Showing papers in "Journal of Dynamic Systems Measurement and Control-transactions of The Asme in 1981"
TL;DR: A new conceptually simple approach to controlling compliant motions of a robot manipulator that combines force and torque information with positional data to satisfy simultaneous position and force trajectory constraints specified in a convenient task related coordinate system is presented.
Abstract: A new conceptually simple approach to controlling compliant motions of a robot manipulator is presented. The 'hybrid' technique described combines force and torque information with positional data to satisfy simultaneous position and force trajectory constraints specified in a convenient task related coordinate system. Analysis, simulation, and experiments are used to evaluate the controller's ability to execute trajectories using feedback from a force sensing wrist and from position sensors found in the manipulator joints. The results show that the method achieves stable, accurate control of force and position trajectories for a variety of test conditions.
2,991 citations
TL;DR: A new approach to the dynamic control of manipulators is developed from the viewpoint of mechanics and it is shown that a linear feedback of generalized coordinates and their derivatives are effective for motion control in the large.
Abstract: Department of Mechanical Engineering, Faculty of Engineering SCience, Osaka University, Toyonaka, Osaka, 560 Japan A new approach to the dynamic control of manipulators is developed from the viewpoint of mechanics. It is /irst shown that a linear feedback of generalized coordinates and their derivatives are effective for motion control in the large. Next, we propose a method for task-oriented coordinate control which can be easily implemented by a micro-computer and is suited to sensor feedback control. The proposed method is applicable even when holonomic constraints are added to the system. Effectiveness of the proposed method is verified by computer simulation.
1,155 citations
TL;DR: In this article, the authors consider a class of linear dynamical systems containing uncertain elements and subject to uncertain inputs, and construct a feedback control, utilizing measured state or estimated state, which guarantees that every system response is ultimately bounded within a certain neighborhood of the zero state.
Abstract: We consider a class of linear dynamical systems containing uncertain elements and subject to uncertain inputs, and for which either uncertain state or output is available. We construct a feedback control, utilizing measured state or estimated state, which guarantees that every system response is ultimately bounded within a certain neighborhood of the zero state. Performance resulting from use of this control is compared with that due to the use of purely linear feedback control.
384 citations
TL;DR: In this paper, the joint torques of a hexapod locomotion vehicle in a tripod gait are computed under equality constraints on the maximum actuator torques and reaction forces at the tip of each chain of the system.
Abstract: Control of the force distribution in locomotion and manipulation systems containing closed kinematic chains is an important problem since many tasks such as walking or grasping depend upon it. The basic problem is to solve for the input joint torques for a particular system trajectory and is usually underspecified. As such, linear programming has been used to obtain a solution which optimizes a weighted combination of energy consumption and load balancings. Inequality constraints on the maximum actuator torques and reaction forces at the tip of each chain of the system are imposed, in addition to equality constraints which specify movement in a desired system trajectory. An example is given in which the joint torques to drive a hexapod locomotion vehicle in a tripod gait are computed.
231 citations
TL;DR: This paper presents a method of obtaining a time schedule of velocities and accelerations along the path that the manipulator may adopt to obtain a minimum traveling time, under the constraints of composite Cartesian limit on linear and angular velocity and acceleration.
Abstract: To assure a successful completion of an assigned task without interruption, such as the collision with fixtures, the hand of a mechanical manipulator often travels along a preplanned path. An advantage of requiring the path to be composed of straight-line segments in Cartesian coordinates is to provide a capability for controlled interaction with objects on a moving conveyor. This paper presents a method of obtaining a time schedule of velocities and accelerations along the path that the manipulator may adopt to obtain a minimum traveling time, under the constraints of composite Cartesian limit on linear and angular velocities and accelerations. Because of the involvement of a linear performance index and a large number of nonlinear inequality constraints, which are generated from physical limitations, the “method of approximate programming (MAP)” is applied. Depending on the initial choice of a feasible solution, the iterated feasible solution, however, does not converge to the optimum feasible point, but is often entrapped at some other point of the boundary of the constraint set. To overcome the obstacle, MAP is modified so that the feasible solution of each of the iterated linear programming problems is shifted to the boundaries corresponding to the original, linear inequality constraints. To reduce the computing time, a “direct approximate programming algorithm (DAPA)” is developed, implemented and shown to converge to optimum feasible solution for the path planning problem. Programs in FORTRAN language have been written for both the modified MAP and DAPA, and are illustrated by a numerical example for the purpose of comparison.
173 citations
TL;DR: Analysis, synthesis, and design of hydraulic servosystems and pipelines as discussed by the authors, Analysis, synthesis and design, and the development of hydraulic systems and pipelines are discussed in detail.
Abstract: Analysis, synthesis, and design of hydraulic servosystems and pipelines , Analysis, synthesis, and design of hydraulic servosystems and pipelines , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
156 citations
86 citations
48 citations
TL;DR: In this article, a mathematical model of a three-mass flexible rotor symmetrically supported on flexibly mounted journal bearings is presented, and three questions are posed: how many control sources are required, what measurement transducers are required and what information about the system dynamics is required in order to implement active control?
Abstract: Some recent experimental studies have been concerned with the stabilization of rotating machinery through control action applied at critical points on the rotor. These studies have tended to ignore fundamental constraints on the positioning of active control inputs and measurement transducers. Such constraints must be considered to ensure both a cost effective design and system integrity in the event of component failure. This paper presents the first stage of a theoretical examination of active control by investigating a mathematical model of a three-mass flexible rotor symmetrically supported on flexibly mounted journal bearings. Three questions are posed: how many control sources are required, what measurement transducers are required and what information about the system dynamics is required in order to implement active control? The multivariable nature of the model and uncertainty about the oil-film dynamics makes general solutions to these problems difficult. However some solutions are proposed based upon the structural properties of the model. It is shown that the general requirements for system identification and control are conflicting. The practical implications of this conflict are discussed.
46 citations
TL;DR: In this paper, a method for the computation of response variance is presented which uses the concept of a "spatial" shaping filter to represent the uneven ground, leading to a state space form for the combination of vehicle and excitation.
Abstract: The motion of vehicles traveling over rough ground at variable speed is nonstationary. In this paper, a method for the computation of response variance is presented which uses the concept of a "spatial" shaping filter to represent the uneven ground, leading to a state space form for the combination of vehicle and excitation. The formulation is for linear systems of arbitrary order and allows any deterministic velocity history to be accommodated easily. An example is discussed in detail.
45 citations
TL;DR: In this article, a unified presentation of the two techniques is possible; the S-STURE being interpreted as a stochastic self-tuning regulator, and the underlying concepts and the structure of these adaptive control systems are described.
Abstract: The control objectives for Model Reference Adaptive Control Systems (MRAC) are specified in terms of a reference model. The control objectives for Stochastic Self-Tuning Regulators (S-STURE) are specified in terms of an ARMA model. These two types of adaptive control systems share a common characteristic (duality). This duality extends the one existing in the linear case with known parameters between modal control (pole-placement) and minimum variance control. Based on the duality properties, a unified presentation of the two techniques is possible; the S-STURE being interpreted as a stochastic MRAC. The underlying concepts and the structure of these adaptive control systems are described. The available theoretical results concerning the analysis of these systems are briefly reviewed. The primary domain of application of these techniques are indicated. An overview of the unsolved problems concludes the paper.
TL;DR: In this article, the authors present a unified treatment of stability and curving mechanics of steel wheel/steel rail vehicles utilizing low order, predominantly linear models, applicable to both conventional and self-steering radial passenger trucks.
Abstract: This paper presents a unified treatment of stability and curving mechanics of steel wheel/steel rail vehicles utilizing low order, predominantly linear models. The analysis is applicable to both conventional and self-steering radial passenger trucks. A six degree of freedom truck model is utilized to illustrate the various instability modes that can occur due to the destabilizing influence of a wheelset. It is shown that the individual wheelset mode, the rigid truck mode and the carbody mode are of academic interest only, while the elastically coupled wheelset mode is the one which limits the performance of intercity trucks. Carbody resonance can occur but is controlled by relatively small amounts of damping in the secondary lateral suspension. A four degree of freedom steady-state curving model is used to investigate the influence of shear and bending stiffness on both off and on-flange curving performance. It is shown that a low bending stiffness provides superior on and off-flange curving and that the selection of the shear stiffness depends upon the severity of the curves to be negotiated. A low shear stiffness improves the ability of the truck to stay off the flange while a high shear stiffness results in a “floating” truck which flanges earlier but results in the lowest flange forces and angle of attack once flange contact occurs.
TL;DR: It is shown that the JNR and other time-duration dependent criteria based on wheel load measurements alone are unsuccessful in predicting derailment safety and the derailment limit can be estimated from quasisteady analysis of wheel/rail forces.
Abstract: This paper shows that the JNR and other time-duration dependent criteria based on wheel load measurements alone are unsuccessful in predicting derailment safety. For wheelclimb processes involving negligible lateral velocities, the derailment limit can be estimated from quasisteady analysis of wheel/rail forces. The evaluation of criteria is based on experiments with a single wheelset and a nonlinear theory for dynamic wheelclimb.
TL;DR: In this article, an approximate method employing a Lyapunov-type function and an associated optimization problem is presented for investigating reachable sets for nonlinear control systems, which is applicable to systems of any dimension and does not require integration of the equations of motion.
Abstract: Two methods are presented for investigating reachable sets for nonlinear control systems. One method, based on a reachability maximum principle, lacks appropriate boundary conditions if the reachable set is not closed. The main result of the paper is an approximate method employing a Lyapunov-type function and an associated optimization problem, both involving a parameter vector. For each value of the parameter vector the resulting estimate for the reachable set (and the intersection of all such estimates) is guaranteed to contain the actual reachable set. The method is applicable to systems of any dimension and does not require integration of the equations of motion.
TL;DR: In this paper, a theory of nonlinear state observers for nonlinear and bilinear distributed parameter systems is presented and convergence results for these observers are proved for closed-loop stability.
Abstract: This paper presents a theory of nonlinear state observers for nonlinear and bilinear distributed parameter systems. Convergence results are proved for these observers. Linear feedback control derived from such state observers is applied to the distributed parameter system and conditions are presented for closed-loop stability. The emphasis is on finite dimensional state observers and controllers (which can be implemented with on-line computers) and conditions for their successful operation with infinite dimensional distributed parameter systems.
TL;DR: In this paper, a review of current research on applications of control systems and theory to achieve energy conservation in automotive vehicles is presented, including controllers for both conventional transmissions and those employing flywheel energy storage.
Abstract: This paper is a review of current research on applications of control systems and theory to achieve energy conservation in automotive vehicles. The development of internal combustion engine control systems that modulate fuel flow, air flow, ignition timing and duration, and exhaust gas recirculation is discussed. The relative advantages of physical and empirical models for engine performance are reviewed. Control strategies presented include optimized open-loop schedule type systems, closed-loop feedback systems, and adaptive controllers. The development of power train and hybrid vehicle control systems is presented, including controllers for both conventional transmissions and those employing flywheel energy storage.