Here we present the control, performance and modeling of an untethered electromagnetically actuated magnetic micro-robot. The microrobot, which is composed of neodymium–iron–boron with dimensions 250 m 130 m 10 m, is actuated by a system of six macroscale electromagnets. Periodically varying magnetic fields are used to impose magnetic torques, which induce stick–slip motion in the micro-robot. ...

A new image-based control strategy for visual servoing of a class of under-actuated rigid body systems is presented. The proposed control design applies to “eye-in-hand” systems where the camera is fixed to a rigid body with actuated dynamics. The control design is motivated by a theoretical analysis of the dynamic equations of motion of a rigid body and exploits passivity-like properties of th...

This work presents the dynamic modeling of an untethered electromagnetically actuated magnetic micro-robot, and compares computer simulations to experimental results. The micro-robot, which is composed of neodymium-iron-boron with dimensions 250 μm x 130 μm x 100 μm, is actuated by a system of 5 macro-scale electromagnets. Periodic magnetic fields are created using two different control methods...

This paper presents an optimal shape trajectory planner for shape-accelerated underactuated balancing systems, which are destabilized by gravitational forces. These systems have unactuated shape variables and fully actuated external variables. They also have the same number of actuated and unactuated degrees of freedom. Their equations of motion result in nonholonomic acceleration/dynamic const...

In order to improve trajectory tracking accuracy for a redundantly actuated parallel manipulator, a so-called augmented nonlinear PD (ANPD) controller based on the conventional dynamic controller is proposed in this paper. The ANPD controller is designed by replacing the linear PD in the augmented PD controller with a nonlinear PD algorithm. The stability of the parallel manipulator system with...

In this note, we consider the problem of choosing which nodes of a linear dynamical system should be actuated so that the state transfer from the system’s initial condition to a given final state is possible. Assuming a standard complexity hypothesis, we show that this problem cannot be efficiently solved or approximated in polynomial, or even quasi-polynomial, time.

A bandwidth-tunable filter has been demonstrated based on a micro-electro-mechanical-system (MEMS) actuated single-crystalline silicon microtoroidal resonator. Bandwidth is tuned from 2.8 to 78.4 GHz by voltage control, the largest bandwidth tuning range reported to date to our knowledge in resonator-based filters. A 21.8 dB extinction ratio is attained as a dynamic add-drop filter.

This paper presents a novel robust fractional PIλ controller design for flexible joint electrically driven robots. Because of using voltage control strategy, the proposed approach is free of problems arising from torque control strategy in the design and implementation. In fact, the motor's current includes the effects of nonlinearities and coupling in the robot manipulator. Therefore, cancella...

In this paper, hysteretic behavior modeling, system identification and control of a mechanism that is actuated by shape memory alloy (SMA) wires are presented. The mechanism consists of two airfoil plates and the rotation angle between these plates can be changed by SMA wire actuators. This mechanism is used to identify the unknown parameters of a hysteresis model. Prandtl–Ishlinskii method is ...