Accurate contour control of mechatronic servo systems usingGaussian networks

This paper presents a method of contour control of mechatronic servo systems by using neural networks. The neural network learns the inverse dynamics of the mechatronic servo system. The input data for the mechatronic servo systems are modified from objective trajectories by using the neural network. The Gaussian network is adopted to construct the inverse dynamics of the mechatronic servo system because the Gaussian function is well defined, and its structure and initial parameters can be systematically selected such that the initial network approximates the inverse dynamics of the mechatronic servo system. The actual input/output data of the mechatronic servo system are used for the learning of the Gaussian network. Effectiveness of the proposed method is assured by experimental results of contour control of an X-Y table     

Artificial realization of human skill for contour control of robot manipulator

A methodology for the artificial realization of expert human skill is described. Artificial human skill was realized in the problem of contour control of mechatronic servo systems including robot manipulators and machine tools. The merits of the artificial human skill thus obtained are discussed. This work was presented, in part, at the International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20, 1996.     

The development of a controller for mechatronics equipment

This paper describes the developmental history of mechatronics equipment controllers especially within Yaskawa Electric. First, the philosophy and definition of the word “mechatronics” are introduced. Then a discussion is presented about mechatronics equipment controllers in which they mean a numerical control (NC) system for machine tools and industrial robots. The NC system covers three fields of technology: controller hardware, software, and an actuator control system (servosystem). Second, the 20-year progress of each item is discussed. Finally, the necessary performance and functions for future NC systems are outlined     

Optimum contouring of industrial robot arms under assigned velocityand torque constraints

Presents a general solution to the contouring problem of industrial robot arms, under the constraints of assigned Cartesian velocity and joint torque/acceleration. The proposed solution is an off-line trajectory generation algorithm and, therefore, it possesses significant industrial implications, as no hardware changes are needed for its implementation. According to the proposed method, the maximum utility of joint torque/acceleration is guaranteed to be bound to the assigned velocity constraint. In the proposed method, a realizable trajectory is generated from the objective trajectory and its delay dynamics are compensated for by using a forward compensator. The proposed method has been experimented with using a Performer MK-3s (PMK-3s) industrial robot arm, and optimum contouring has been realized     

Enhanced contour control of SCARA robot under torque saturationconstraint

Contour control of a robot arm is an act of the end-effector tip being moved along a reference Cartesian path, with an assigned velocity. When torque saturation occurs, and lasts for some time, contour deteriorations result. In addition, system delay dynamics also causes contour deteriorations. In this paper, an offline trajectory generation algorithm is described, which achieves both optimum avoidance of torque saturation and delay dynamics compensation     

Accurate contour control of mechatronic servo systems without parameter adjustment by use of modified input data method

This paper describes a technique of accurate contour control by a modified input data method for industrial mechatronic servo systems with unadjusted servo parameters. Adjustment of the servo parameters in order to achieve high‐performance contour control in mechatronic servo systems is a tedious task. The modified input data method can realize satisfactory contour control performance accuracy within rather large tolerances for servo parameter errors. The effectiveness of the proposed method has been verified by simulation and experimental studies of contour control of an actual mechatronic servo system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(4): 60–69, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20322     

Dual mode synchronous positioning with switching of master–slave axes by using a torque signal for contour control of articulated robot arms

Dual mode synchronous positioning control with switching of master and slave axes is proposed to realize accurate contour control of industrial robot arms. The axis which is contaminated with disturbance is selected as the master axis, then the disturbances in both first axis and second axis can be compensated. The effectiveness of the proposed method was verified by experimental results of an actual articulated robot arm. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 33–40, 2002     

Pole selection of feedforward compensators considering bounded control input of industrial mechatronic systems

A new pole selection method for feedforward compensators of mechatronic servo systems is presented in this paper. It is necessary to have the system poles located at desirable positions on the s-plane in order to realize better servoing performance. However, selection of new poles is not a straightforward problem and in most industrial mechatronic systems, it has been a mere cut-and-dry procedure. In this research, feedforward compensator poles are related to the control input, and a criterion was developed to determine the desirable poles that improve the control input within its limits. This method was developed for the second-order model and it was simulated and experiments were performed with the Performer MK3s articulated industrial robot manipulator. Some attractive results have been obtained with the new method.     

Mechatronics-an industrial perspective

The term "mechatronics" is defined to provide a framework for technical and practical considerations. Within this framework, the importance of "intimate and organic" integration in mechatronics product designs is raised. Several issues pertaining to attaining this ideal integration of mechanical, electronic controls, and system engineering in mechatronics product designs are cited. To further advance the current mechatronics products, areas of improvement are also presented.     

Vibration Absorption Control of Industrial Robots by Acceleration Feedback

This paper describes an electrical control method of absorbing arm vibrations of industrial robots. Arm vibration problems are divided into two categories: resonance vibration phenomenon depending on actuator velocity and transient oscillations caused by acceleration change of actuators. Because resonance frequency of an industrial robot changes more than double due to the arm posture, mechanical vibration absorbing methods may not be easily utilized. The method applied in this paper is to compose dampers as electric manners by utilizing arm acceleration feedback to actuators of an industrial robot. Acceleration sensors are attached on three axes which construct a robot arm. Acceleration signals are fed back to the corresponding actuators passed through phase compensation circuits. By experiments applied to an industrial robot, this method has been proved to be effective in eliminating both resonance and transient vibrations. According to this control, a smart motion industrial robot which does not have resonance characteristics and operates speedily and smoothly has been realized.