Interpolating gain-scheduled H∞ loop shaping design for high speed ball screw feed drives.

This paper presents a method to design servo controllers for flexible ball screw drives with time-varying dynamics, which are mainly due to the time-varying table position and the workpiece mass. A gain-scheduled H∞ loop shaping controller is designed to achieve high tracking performance against the dynamic variations. H∞ loop shaping design procedure incorporates open loop shaping by a set of compensators to obtain performance/robust stability tradeoffs.

Food utilization and growth of cutworm Spodoptera litura Fabricius larvae exposed to nickel, and its effect on reproductive potential.

Food utilization and growth of the 5th and 6th instar Spodoptera litura Fabricius larvae, and its effect on reproduction potential was evaluated by feeding larvae diets with different doses of Ni for 3 generations. Dose-dependent relationships between Ni levels and food consumption and growth were variable with different larval developmental period and Ni exposure duration. RCR, AD and RGR of the 6th instar larvae were much more affected by Ni exposure than those of 5th instar larvae, and the effects were strongest in the 3rd generation.

Adaptive backstepping sliding mode control of flexible ball screw drives with time-varying parametric uncertainties and disturbances.

This paper presents a method to model and design servo controllers for flexible ball screw drives with dynamic variations. A mathematical model describing the structural flexibility of the ball screw drive containing time-varying uncertainties and disturbances with unknown bounds is proposed. A mode-compensating adaptive backstepping sliding mode controller is designed to suppress the vibration.

The effect of dietary nickel on the immune responses of Spodoptera litura Fabricius larvae.

By exposing Spodoptera litura Fabricius larvae to nickel (Ni) in artificial diets for successive three generations, we investigated the impacts of the dietary Ni on growth and immune response of the fifth and sixth instar larvae at 24 h intervals. The time of newly moulted fifth instar larvae was labelled as 0 h. After exposure to 5 mg/kg Ni for two generations, Ni exposure significantly improved larval phenoloxidase activity and encapsulation grade in fifth instar larvae when compared to controls, except for encapsulation grade at 72-120 h in the second generation.