Tsutomu Ohmae

A Microprocessor-Controlled High-Accuracy Wide-Range Speed Regulator for Motor Drives

A new speed measurement system, which is suitable for microprocessor-based motor drive, and its application to speed regulator are explained.

A Microprocessor-Controlled Fast-Response Speed Regulator with Dual Mode Current Loop for DCM Drives

A new control method is described in which a microprocessor is used to regulate the speed of a dc motor driven by antiparallel-connected three-phase dual thyristor converters. A distinct feature of this speed regulating system is that speed response is improved by using a fast-response current controller for the internal loop. A fast-response current controller is obtained by employing a nonlinear compensation subloop and a proportional plus integral compensation subloop. The nonlinear compensation subloop is used to linearize the nonlinear load characteristics of the thyristor converter, which are encountered under discontinuous conduction states of current. The proportional plus integral compensation subloop reduces the deviation of detected current from the current reference. With these two current-control subloops a fast motor speed response is achieved under discontinuous as well as continuous conduction states; hence the steady-state accuracy of speed is improved. A speed regulator using a microprocessor was trial manufactured and tested with a 20-kW dc motor. It was found that an extremely fast controlled current response can be obtained even with a relatively long sampling period. Further, normal action was confirmed in four-quadrant operation.

A microprocessor-controlled speed regulator with instantaneous speed estimation for motor drives

A method for estimating instantaneous speed, suited for a microprocessor-based speed regulator for motor drives, and the characteristics of the speed control system are described. Features of the proposed method include the estimation of instantaneous speed at a real-time point using values of average speed detected by counting for a certain time the output pulses of an encoder as well as the estimated value as the speed feedback signal for the speed regulator. Since this method allows compensation to be made for the lag time of the feedback signal caused by detection of the mean value, it contributes to improved stability of the speed regulator. In particular, this provides a significant suppression of the vibrations that are generated in motor-driven machinery. >

A Microprocessor-Based Motor Speed Regulator Using Fast-Response State Observer for Reduction of Torsional Vibration

A new state observer, which is suitable for microprocessor-based motor drives, and its application to suppression control of shaft torsional vibration are described. A distinct feature of the state observer is that a fast-response load torque estimation is obtained by processing the detected motor current and the encoder output pulses by a hardware circuit for each encoder pulse generation. Suppression control of the shaft torsional vibration is achieved by calculating a compensation signal from the estimated load torque with the microprocessor software. A microprocessor-based speed regulator for dc motor drives, which utilizes the state observer and suppression control of the shaft torsional vibration, was developed for evaluation purposes and tested with a 15-kW dc motor. The load torque of the motor can be estimated accurately, even with a 15-Hz vibration frequency, and the torsional vibration can be eliminated with the proposed suppression control.

A Fully Digitalized Speed Regulator using Multimicroprocessor System for Induction Motor Drives

A fully digitalized speed regulator is proposed which executes all regulatory processing by using a multimicroprocessor. The hardware configuration of the regulator is standardized. A vector control algorithm is used to perform fast response speed control of an induction motor. Microprocessors execute a PWM gate pulse generation and current component detection in addition to speed control processing. In applications of the regulator to a 1.5-kW induction motor drive system, Its effectiveness is confirmed.

Servo System Using Optical Serial Transmission in Control Loop for Industrial Robots

A new servo system suitable for robot control is proposed. An optical serial transmission is applied in its servo-control loops to reduce the number of signal cables and the cable length between the robot mechanism and the controlling equipment, as well as to increase flexibility for expanding control functions.

A Microprocessor-Based Current Controller with an Internal Current-Rate Loop for Motor Drives

A new current-control method that is suitable for microprocessor-based speed regulation of motor drives is described. The method achieves fast-response and high-accuracy performance by using a major current loop and an internal current rate loop. The former loop is used to control precisely the mean value of the motor current by employing a current feedback signal obtained from a smoothing filter of the rippled current. The latter loop is used to stabilize the major loop with a high gain and to limit the variation rate of the motor current by employing the current feedback signal obtained from the instantaneous current without time delay. A current controller using a microprocessor was trail-manufactured and tested with a thyristor-converter-driven dc motor. It was found that fast-controlled current response can be obtained, even with a relatively long sampling period.

MICROPROCESSORS SYSTEMS FOR MOTION CONTROL.

Abstract This paper presents a review of the recent advances in microcomputer-based motion control systems. At first, the trends of microcomputers and systems are described. As a result, it was clarified that multiple microcomputer systems are suitable for motion control. Rolling mill main drives and robots are used as the application examples and their hardware configurations are described. Furthermore, some of the future technical trends of the above systems are also described.

A SERVO COMMAND-BASED FLEXIBLE SERVO SYSTEM FOR INDUSTRIAL ROBOTS

Abstract A new servo system which enables flexible motion control of an industrial robot is proposed, A servo command interface is introduced in the servo system to realize a flexible control function and standardized software configuration. Servo command interpretation and multi-axis digital servo processing are executed by a DSP. A position and speed control loops are constructed using detected and estimated state variables. The proposed servo system is applied to the robot controller for a 6-axis industrial robot and its effectiveness is confirmed.

A Servo Command-Based Flexible Servo System for Industrial Robots

Abstract A new servo system which enables flexible motion control of an industrial robot is proposed. A servo command interface is introduced in the servo system to realize a flexible control function and standardized software configuration. Servo command interpretation and multi-axis digital servo processing are executed by a DSP. A position and speed control loops are constructed using detected and estimated state variables. The proposed servo system is applied to the robot controller for a 6-axis industrial robot and its effectiveness is confirmed.