Among the electric motor drives, the piezoelectric actuator (PA) is one drive which is becoming very popular in high precision biomedical applications, such as intracytoplasmic sperm injection. The main benefits of a PA include low thermal losses and, most importantly, the high precision and accuracy achievable consequent of the driect drive principle. One major source of uncertainties in PA control design is the hysteresis behavior which yields a rate-independent lag and residual displacement near zero input, reducing the precision of the actuators. Due to the typical precision positioning requirements and low offset tolerance of PA applications, the design and control of these systems, under the influence of these uncertainties, is particularly challenging since conventional PID control usually does not suffice in these application domains to meet the stringent performance requirements.
In this paper, we consider the design and realization of a piezo stack actuator which is capable of linear motion and non-full rotation to fulfill the stringent requirements associated with sperm injection applications. A complementary precise control system is developed employing a robust adaptive control algorithm to reject the hysteresis phenomenon associated with general PAs and to achieve rapid and highly precise positioning. The controller comprises of a PID feedback component and an adaptive component for hysteresis compensation. The adaptive component is continuously refined based on just prevailing input and output signals. In the paper, it will be proven that the tracking error can asymptotically converge to zero. In addition, analytical quantification is given to illustrate the improvement of the system's transient performance. Real-time experimental results verify the effectiveness of the proposed micro actuator for high precision motion trajectory tracking in intracytoplasmic sperm injection using mice eggs.