The multi actuator drive technology was unveiled by Seagate in December 2017, a breakthrough that can almost double the data performance of the future generation hard disk drives. This technology will equip drives with dual actuators operating on the same pivot point. Each actuator will control half of the drive’s arms. Since two actuators operate independently on the same pivot timber, the control forces and torques generated by one actuator can affect the operation of the other actuator. We will have a scenario when one actuator is track seeking and the other actuator is in the track following mode. The track seeking actuator will impart vibration disturbances to the track following actuator. Previously, we presented a single-input single-output (SISO) data-driven feedforward control design method (Shah and Horowitz, 2019. “Active Vibration Rejection in Multi Actuator Drives: Data Driven Approach,” Dynamic Systems and Control Conference, Vol. 3) to obtain feedforward controllers for the voice coil motor (VCM) and the micro actuator sequentially. The design was based on multiple frequency response measurements of the actuators. In this paper, first, we present a single-input multi-output (SIMO) data-driven feedforward control design technique to simultaneously obtain feedforward controllers for the VCM and the micro actuator. This methodology will obtain a common controller for multiple drives. We will compare the performance of this algorithm with the sequential SISO design technique (Shah and Horowitz, 2019. “Active Vibration Rejection in Multi Actuator Drives: Data Driven Approach,” Dynamic Systems and Control Conference, Vol. 3). Second, we present an add-on input shaping technique to suppress the residual vibration.

Active and passive control techniques have been devised over the years to mitigate the effect of vibrations on drill-string life with varying degrees of success. Here, it is proposed to design a robust trajectory tracking controller, which ultimately forces the rotary table and the drill-bit to move with the same speed (speed synchronization), hence reducing/eliminating torsional vibrations from the drill pipes. A model of the rotary drilling system, which includes torsional stick-slip, is first developed; then, an integral sliding mode control with time-varying exponent (ISMC-TVE) scheme is developed such that the bit motion tracks that of the rotary table to mitigate the effects of the induced vibrations. The ISMC-TVE is able to control the transient stage of the drill-string system’s response, maintain the system in the sliding state even under abrupt or existing external disturbances, and guarantee asymptotic stability of the rotary drilling system. The Lyapunov stability theorem is used here to analyze the performance of the closed-loop system, and the simulation results showed that the ISMC-TVE law is capable of accurately synchronizing the bit and rotary table speeds.

Highly automated vehicles (HAVs) must be rigorously evaluated before they are deployed on public roads. An accelerated evaluation framework was proposed in the literature to test HAVs more efficiently. However, running such a test is challenging due to the fact that some of the generated test cases may be not feasible or realistic. This paper proposes an improved accelerated evaluation framework that combines importance sampling with reachability analysis, so that the feasibility of all test cases are guaranteed, and the risk levels of cases are controlled. The performance of the proposed framework is studied using the unprotected pedestrian crossing scenario. A total od 2689 pedestrian–vehicle interaction events are extracted from open-source video data, and a truncated Gaussian mixture model (TGMM) is developed to describe the pedestrian–vehicle interaction. Simulation results show that the proposed method achieves unbiased crash rate estimation in an accelerated fashion while achieving the aforementioned benefits for test case generation (feasible and at controlled risk level).