This paper addresses the motion control in joint space of robot manipulators with friction described by the generalized LuGre friction model. The paper extends the nonadaptive version of the Slotine and Li’s control system originally designed for friction–free manipulators to the case where a friction observer is incorporated to deal with friction. This observer corresponds to an adaptation of ...

In the paper, a low friction pneumatic cylinder and a sliding table, and both of them are embedded with aerostatic bearings are designed. A low friction pneumatic table is constructed by combining the pneumatic cylinder and the sliding table. The characteristics for the friction force versus velocity of the pneumatic cylinder and the pneumatic table are measured. Moreover, a hybrid self-tuning ...

In this paper, robust adaptive NN control is investigated for small form factor hard disk drives which is mainly used in mobile applications. The hysteresis friction nonlinearity from the pivot bearing degrades the servo performance, as hard disk drive servo system operates in track-following mode. To deal with the effect of hysteresis friction nonlinearity, adaptive hysteresis friction compens...

In this paper, de-coupled discrete-time sliding-mode tracking controllers are designed for an x-y sliding table driven directly by linear motors. The controllers are designed using an integrated reaching law method, based on a simplified model of the current control loop of these motors. To achieve high bandwidth tracking performance, a feedforward controller is added. Although the sliding tabl...

Two adaptive nonlinear friction compensation schemes are proposed for second-order nonlinear mechanical systems with a partially known nonlinear dynamic friction model to achieve asymptotic position and velocity tracking. The first scheme has auxiliary filtered states so that a simple open-loop observer can be used. The second one has a dual-observer structure to estimate two different nonlinea...

Starting from the well-known fact that the rolling movement always has a lower friction compared to sliding friction, the authors have conceived and realized a pivoting movement joint on a "layer of balls" with "compensation space", placed between the acetabular cup and the femoral head. This technical solution allows free self-directed migration of the balls, depending on the resistance oppose...