Showing papers in "Journal of Dynamic Systems Measurement and Control-transactions of The Asme in 1986"

Industrial Robot Forward Calibration Method and Results

Abstract: Methode d'etalonnage d'un robot industriel et resultats (les coordonnees de l'outil sont obtenues a partir des valeurs des codeurs situes aux articulations)

A Finite Element/Lagrange Approach to Modeling Lightweight Flexible Manipulators

Abstract: This paper presents a finite element/Lagrangian approach for the mathematical modeling of lightweight flexible manipulators. Each link of the manipulator is treated as an assemblage of a finite number of elements for each of which kinetic and potential energies are derived. These elemental kinetic and potential energies are then suitably combined to derive the dynamic model for the system. It is contended that satisfactory modeling and analysis of the manipulator dynamics can lead to the use of advanced control techniques to solve some of the problems associated with the flexure of otherwise attractive lightweight manipulator arms. Detailed model development and simulation results for the case of a two-link manipulator system are presented.

An adaptive control scheme for mechanical manipulators. Compensation of nonlinearity and decoupling control

Abstract: This paper presents a new adaptive control scheme for mechanical manipulators. Making use of the fundamental properties of the manipulator equations, an adaptive algorithm is developed for compensating a nonlinear term in the dynamic equations and for decoupling the dynamic interaction among the joints. A computer simulation study is conducted to evaluate the performance of a manipulator control system composed of the manipulator, adaptive nonlinear compensator/decoupling controller and state feedback controller with integral action. Simulation results show that the manipulator control system with adaptive controller is insensitive to variations of manipulator configurations and payload.

Model Reference Adaptive Control of Feed Force in Turning

Abstract: Application de la technique de conception avec commande adaptative avec reference a un modele a une seule entree, une seule sortie en temps discret, technique de Landau et de Lozano, au probleme de regulation de la force d'avance sur un tour dans diverses conditions de coup

Control of Elastic Robotic Systems by Nonlinear Inversion and Modal Damping

Abstract: Energy efficient, lightweight robot arms for space applications have considerable structural flexibility. For large and fast motions, both the nonlinear coupled dynamics and the elastic behavior of the robots must be considered in control system designs. This paper presents an approach to the control of a class of flexible robotic systems. A control law is derived which decouples the joint-angle motion from the flexible motion and asymptotically decomposes the elastic dynamics into two subsystems, representing the transverse vibrations of the elastic link in two orthogonal planes. This decomposition allows the design of an elastic mode stabilizer independently based on lower order models representing structural flexibility. The closed-loop system is shown to be globally asymptotically stable and robust to uncertainty in system parameters. Simulation results are presented to show that large, fast control of joint angles can be performed in spite of space vehicle motion and uncertainty in the payload.

Mechanical Behavior and Design Equations for Elastomer Shear Pad Remote Center Compliances

Abstract: Comportement mecanique et equations de dimensionnement de transmissions elastiques avec patins de cisaillement en elastomere (dispositifs elastiques avec centre de compliance eloigne)

Dynamic Simulation of a Leadscrew Driven Flexible Robot Arm and Controller

Abstract: High performance requirements in robotics have led to the consideration of struc­ tural flexibilty in robot arms. This paper employs an assumed modes method to model the flexible motion of the last link of a spherical coordinate robot arm. The model, which includes the non backdrivability of the leadscrews, is used to in­ vestigate relationships between the arm structural flexibility and a linear controller for the rigid body motion. This simple controller is used to simulate the controllers currently used in industrial robots. The simulation results illustrate the differences between leadscrew driven and unconstrained axes of the robot; they indicate the trade-off between speed and accuracy; and show potential instability mechanisms due to the interaction between the controller and the robot structural flexibility.

A Model-Based Approach to Adaptive Control Optimization in Milling

Abstract: An adaptive control optimization system using a model to represent actual physical phenomena in milling is discussed. The model is used for the identification of physical parameters, the calculation of the temperature at the tool edges, and the estimation of the tool wear rate. The shear angle of the shear plane, the flank wear land length of the tool edge, the true contact area at the flank wear land, the radial depth and the axial depth of cut are identified as the physical parameters, the shear stress, and the hardness of the work material from bending moments and torque in the spindle generated by the cutting force. The temperature at the flank wear land is calculated from identified parameters. The tool wear is represented theoretically as the summation of the thermal, mechanical and shock wears. Each wear is calculated from identified parameters and the temperature at the tool edges. Adaptive control experiments to keep the tool-wear rate at a constant value verify that the total system works well. An adaptive control optimization system using the tool-wear rate equation is compared with an adaptive control constraint system using Taylor’s tool life equation in a computer simulation. The simulation shows that adaptive control optimization gives higher cost efficiency than adaptive control constraint when the process parameters vary.

Vibro-Impact Analysis of Control Systems With Mechanical Clearance and Its Application to Robotic Actuators

Abstract: Analyse des chocs et des vibrations dans un systeme de commande muni de jeux mecaniques. Application aux actuateurs de robots

Limit Cycle Prediction Conditions for a Class of Hydraulic Control System

Abstract: Conditions de prevision des cycles limites pour une classe de systemes de commande hydraulique

Two Contrasting Versions of the Optimal Active Vehicle Suspension

Abstract: Etude de 2 indices de performances qui conduisent a des lois de reaction variable a l'etat optimal pour la force de suspension

Closed-form solutions for a class of optimal quadratic regulator problems with terminal constraints

Abstract: Closed-form solutions are derived for coupled Riccati-like matrix differential equations describing the solution of a class of optimal finite time quadratic regulator problems with terminal constraints. Analytical solutions are obtained for the feedback gains and the closed-loop response trajectory. A computational procedure is presented which introduces new variables for efficient computation of the terminal control law. Two examples are given to illustrate the validity and usefulness of the theory.

Linearization and Sensitivity Models of the Newton-Euler Dynamic Robot Model

Abstract: Within the framework of the Newton-Euler formulation of robot dynamics, linearized and trajectory sensitivity models are constructed about a nominal trajectory. The approach illustrates the property that linearization of the O(N) recursive Newton-Euler formulation leads to O(N) recursive algorithms. These algorithms are conceived for simulation, parameter identification, and real-time control applications which require the numerical evaluation of the linearized or trajectory sensitivity models. The O(N) linearized recursive algorithms complement their O(N5 ) linearized Lagrange (Lagrange-Euler) counterparts which are conceived for physical insight, and manipulator and controller design.

Improvement in the Computing Time of Robot Manipulators Using a Multimicroprocessor

Abstract: A multimicroprocessor having a hardware circuit designed to aid the synchronization of CPUs and software to schedule tasks on the CPUs is proposed. The system is applied to the calculation of the joint angles of six-axis robot manipulators. It is verified that the scheduling software gives the optimum schedule for an elbow manipulator and a sub-optimum one for the Stanford manipulator. Actual calculations on the multiprocessor verifies that the computing time is decreased to 3.6 ms by the proposed parallel processing using seven CPUs and seven APUs, while it takes about 20 ms by ordinary processing using one CPU and one APU.

A Preliminary Investigation of the Dynamic Stability of Flexible Manipulators Performing Repetitive Tasks

Abstract: The governing equations of motion for the compliant coordinates describing a flexible manipulator performing repetitive tasks contain parametric excitation terms. The stability of the zero solution to these equations is investigated using Floquet theory. Analytical and numerical results are presented for a two-degree-of-freedom model of a manipulator with one prismatic joint and one revolute joint.