Pulse with modulation (PWM) is widely used in proportional control systems for it is efficient, flexible and anti-interference. Due to the friction and hysteresis of electromagnet, hysteresis exists when hydraulic valve in steady-state, and hysteresis influences the dynamic characteristics of the valve seriously, the hysteresis can be improved by superimposing dithers with certain frequency and...

This paper describes the finite element (FE)-based design of a slotted tubular permanent magnet actuator (TPMA) used in railway vehicle active lateral secondary suspension that improves the actuator’s thrust and lowers its cogging force under thermal and geometric constraints. To consider the electromagnetic and thermal fields and the complex interactions among the design variables, design was ...

–This paper deals with a small mobile device, "Seal Mechanism," with three degrees of freedom (DOFs). An L-shaped structure of Seal Mechanism is proposed. This device consists of two controlled Electromagnets FA and FB connected by two Piezoelectric actuators EA and EB with Electromagnet FC that generates a constant friction. The friction at FA and FB are alternated by an on-off control. The wh...

The mathematical basis for bias linearization of quadratic magnetic actuators, as typified by magnetic bearings, is developed. The approach generalizes prior ad–hoc methods of linearizing the relationship between actuator force and electromagnet current, obviating the earlier assumptions of stator symmetry. This relationship is fundamentally quadratic in the regime where the magnetic material i...

Magnetic manipulation is a promising technique for lab-on-a-chip platforms. The magnetic approach can avoid problems associated with heat, surface charge, ionic concentration and pH level. The present paper investigates the migration of diamagnetic particles in a ferrofluid core stream that is sandwiched between two diamagnetic streams in a uniform magnetic field. The three-layer flow is expand...

In this paper, we are presenting a new type of pointing interface for computers which provides mouse functionalities with near surface haptic feedback. Further, it can be configured as a haptic display where users may feel the basic geometrical shapes in the GUI by moving the finger on top of the device surface. These functionalities are achieved by tracking three dimensional positions of the n...

In this paper, we address the problem of controlling an active magnetic bearing with reduced ohmic power losses. A solution is proposed which introduces an exponentially decaying bias ßux in the nonlinear control law. To avoid control singularities, the closed-loop system is exponentially stabilized at a faster rate than the bias decay. In the steady state, the proposed controller has zero bias...