High speed and high accuracy positioning systems are essential elements in advanced manufacturing systems such as semiconductor industry(eg. wire bonder). Demands on higher productivity and product quality call for the development of high performance positioning devices and accompanying control algorithms.
The Linear Motor has been hailed as the motion device of the next generation because of its superior performance compared to conventional linear positioning devices such as ball-screw drives. The most attractive features of the linear motor for precision motion control are the absence of backlash and compliance.
Industry has favored classical controllers such as PID due to their structural simplicity and well-known characteristics. As performance requirements become more stringent, conventional controllers often fail because of system uncertainties, the presence of high-order dynamics and nonlinearities such as friction(coulomb,viscous and stiction) and actuator saturation.
In this research, several advanced estimation and control algorithms will be used to overcome such difficulties. For example, several kinds of sensors will be used indipendently or with combination for better estimation of system nonlinearities and control purpose. Several control algorithms will be applied to obtain desired performance specifications, such as Feedback, Feedforward, Friction Compensator, Disturbance Observer, etc. After all, using current setup with NSK Linear Motor, those algorithms will be applied for verification purpose.(Dong-Jun Lee, August 1999)
