Autocompensation of torque ripple of direct drive motor by torque observer

Dept. of Electr. & Comput. Eng., Nagoya Inst. of Technol.
IEEE Transactions on Industry Applications (Impact Factor: 1.67). 02/1993; DOI: 10.1109/28.195906
Source: IEEE Xplore

ABSTRACT Since a direct drive motor (DDM) does not require a reduction
gear, the drive system can be made simple, and therefore it is used in
high-precision robot and machine tool applications. However, without
reduction gear, a disturbance torque is directly reflected to the motor
shaft, and a torque ripple generated by the motor is directly
transmitted to the load, causing poor speed control characteristics. An
improved torque control system for DDM with a permanent magnet rotor,
equipped with a torque observer implemented by digital signal software,
is proposed. The speed fluctuation can be fully removed with a torque
feedforward loop

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes a robust control scheme for high-speed and long stroke scanning motion of high precision linear motor system consisting of linear motor, air bearing guide and position measurement system using heterodyne interferometer. Nowadays, semiconductor process and inspection of wafer or LCD need high speed and long travel length for their high throughput and extremely small velocity fluctuations or tracking errors. In order to satisfy these conditions, linear motor system are widely used because they have large thrust force and do not need motion conversion mechanisms such as ball screw, rack & pinion or capstan with which the system are burdened. However linear motors have a problem called force ripple. Force ripple deteriorates the tracking performances and makes periodic position errors. So, force ripple must be compensated. To maximize the tracking performance of linear motor system, we propose the control scheme which is composed of a robust control method, Time Delay Controller (TDC) and a feedforward control method, Zero Phase Error Tracking Control (ZPETC) for accurate tracking a given trajectory and an adaptive force ripple compensation (AFC) algorithm fur estimating and compensating force ripple. The adaptive ripple compensation is continuously refined on the basis of tracking error. Computer simulation results based on modeled parameters verify the effectiveness of the proposed control scheme for high-speed, long stroke and high precision scanning motion and show that the proposed control scheme can achieve a sup error tracking performance in comparison to conventional TDC control.
    Journal of the Korean Society for Precision Engineering. 01/2005; 22(12).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a solution for observer based diagnostic system in high speed train with induction motor. The concept of the diagnostic system is dedicated to the mechanical part of the drive. The system is monitoring both motor speed sensor and torque transmission system. In case of speed sensor fault the control system could be switched into sensorless mode. Monitoring of torque transmission system allows to limit the motor torque in case of serious problem and gives an information to maintenance center for testing the suspected gear. The proposed system was verified by simulation and in test bench for 1.2 MW rail induction motor.
    Power Electronics and Motion Control Conference, 2008. EPE-PEMC 2008. 13th; 10/2008
  • [Show abstract] [Hide abstract]
    ABSTRACT: Torque ripple minimisation is achieved by an adaptive feedforward control for mass produced permanent magnet synchronous motors. Torque ripple, a major problem for such motors can be reduced using appropriate estimation scheme from speed information. The proposed method employs online zero phase filtering which can effectively minimise all torque harmonics at low speed operation. Experimental results validate the proposed scheme reducing the torque ripple factor from 6.87% to 1.28% using the proposed method. The adaptation scheme make use of PD type iterative learning control scheme which has the advantage of fast convergence compared to the more commonly used P type iterative learning control. The PD-ILC scheme is also quite robust to an initial error in the estimation of the parameter J.