Improvement of Optical Disk Controller Using a MEMS Accelerometer

Abstract

As the usage of optical disks in outdoor equipments is increasing, robust methods of reading and writing data under vibratory conditions should be developed. This paper proposes a method of directly feeding forward signals from a MEMS accelerometer. Newly developed MEMS accelerometers are so small that it does not require any design modification to mount them on the surface of a current optical pickup. The influence of the external vibration can be effectively cancelled by feeding forward the acceleration measured by a MEMS accelerometer mounted on the optical pickup. This paper presents a detailed equation of motion of the optical pickup in subject to external vibration applied to the base. Linear quadratic controller and sliding mode controller are designed separately. The effectiveness of the proposed control system is verified using simulations with realistic inputs. For all considered cases, the system showed excellent performance improvement in terms of disturbance rejection in low frequency region.