This paper discusses the design and implementation of two track-following controllers for dual-stage hard disk drive servo systems. The first controller is designed by combining an outer loop sensitivity-decoupling (SD) controller with an inner loop disturbance observer (DOB). The second is designed by combining mixed H 2 /H ∞ synthesis techniques with an… (More)
was limited by numerous non-off-track modes in the sensor signal.
This paper discusses optimal H ∞ control synthesis via discrete Riccati equations for discrete linear periodically time-varying (LPTV) systems. Based on the results presented in , an explicit minimum entropy H ∞ controller for general time-varying systems is obtained. The control synthesis technique is subsequently applied to LPTV systems and it is shown… (More)
This paper describes the integration of thin film ZnO strain sensors onto hard disk drive suspensions for improved vibration suppression for tracking control. Sensor location was designed using an efficient optimization methodology based on linear quadratic gaussian (LQG) control. Sensors were fabricated directly onto steel wafers that were subsequently… (More)
This chapter presents two new control synthesis approaches for dual-stage track-following servo systems. Both approaches are based on H 2 guaranteed cost analysis, in which an upper bound on the worst-case H 2 performance of a discrete-time system with gain-bounded unstructured causal LTI uncertainty is determined by solving either a semi-definite program… (More)
—Missing position error signal sampling data in hard disk drives (HDDs) results in their servo systems having irregular sampling rates (ISRs). With the natural periodicity of HDDs, which is related to the disk rotation, HDD servo systems with ISRs can be modeled as linear periodically time-varying systems. Based on our previous results, an explicit minimum… (More)
PID control is widely used in air conditioning system. The algorithm is simple but has a long response time, and the adjustment is not flexible. In this paper, we propose a method of optimizing PID controller parameters based on adaptive genetic algorithm. Specifically, the fitness function with penalty terms is added to the classical genetic algorithm and… (More)
Missing position-error-signal sampling data in hard disk drives (HDDs) results in their servo systems having irregular sampling rates. Due to the natural periodicity of HDDs, which is related to the disk rotation, HDD servo systems with missing samples can be modeled as linear periodically time-varying (LPTV) systems. Based on previous H ∞ control synthesis… (More)