Actuator Rotor Research Articles

Spherical actuator attitude measurement method based on multi-to-one WPT modeling

The measurement system of contact spherical actuator has the disadvantages of large friction resistance and poor rotor positioning accuracy. The structure or calculation of non-contact attitude measurement system is complicated. In order to solve the above problems, a multi-to-one wireless power transmission (WPT) spherical actuator attitude measurement method is proposed. The model of mutual inductance(MI) is built. This method effectively shortens the time of finite element analysis(FEA). Three motion states (spin, yaw and tilt) of actuator rotor are analyzed by using this measurement method. Compared with the micro electro mechanical system (MEMS) and fast complementary filter (FCF), the initial attitude error of this method is about 50% of that of the other two methods. Compared with MEMS method, the average angle error of WPT method is reduced by 35%. Experimental results show that this method has good real-time performance and repeatability.

Achieving Commutation Control of an MRI-Powered Robot Actuator

Actuators that are powered, imaged, and controlled by magnetic resonance (MR) scanners could inexpensively provide wireless control of MR-guided robots. Similar to traditional electric motors, the MR scanner acts as the stator and generates propulsive torques on an actuator rotor containing one or more ferrous particles. Generating maximum motor torque while avoiding instabilities and slippage requires closed-loop control of the electromagnetic field gradients, i.e., commutation . Accurately estimating the position and velocity of the rotor is essential for high-speed control, which is a challenge due to the low refresh rate and high latency associated with MR signal acquisition. This paper proposes and demonstrates a method for closed-loop commutation based on interleaving pulse sequences for rotor imaging and rotor propulsion. This approach is shown to increase motor torque and velocity, eliminate rotor slip, and enable regulation of rotor angle. Experiments with a closed-loop MR imaging actuator produced a maximum force of 9.4 N.

A model-based flexural rotor vibration control in cage induction electrical machines by a built-in force actuator

In this paper active control of flexural rotor vibration in electrical machines is examined. We consider attenuation of discrete low-frequency range forced vibration components by means of an adaptive harmonic control strategy. A built-in force actuator for actively generating force on the machine rotor is investigated. Previously, such an actuator has mainly been used in bearingless machine design for rotor levitation. The action of the actuator is based on electromechanical interaction between the rotor and the stator of the machine. A low-order linear parametric state-space model is derived for the actuator–rotor system. Parameter estimation is carried out using simulation data obtained from a detailed two-dimensional time-stepping finite element field-circuit model of the machine. Hence, model-based control design is performed using the identified model. The controller is verified by embedding it into the finite element analysis. As a result we present a virtual plant of the machine with vibration control. The virtual plant is introduced as a means of vibration control design prior to implementing the control algorithms in a real machine. Simulation results using real machine data and finite element time-stepping method are presented.

Finite element modeling of a two‐degree of freedom spherical actuator

PurposeComputational validation of the new concept of the rotor of the two‐degree of freedom spherical actuator is the aim of this paper.Design/methodology/approachThe first approach study leading to optimize the rotor's structure and parameters, realized using finite element method‐based software is presented. Rotor with two layers and rotor with ferromagnetic so‐called “teeth” crossing external layer are discussed.FindingsIt is shown that the rotor with teeth ensures higher torque and efficiency, but a negative slot effect appears, which is, however, possible to reduce.Research limitations/implicationsLimitations in the 3D simulations, especially lack of the movement modeling possibility. For the future the study of some other parameters such as the influence of the magnetic material's saturation, the geometrical from of the tooth and the appearance of the higher harmonics in the signal connected to the non‐sinusodial coupling between the rotor and the stator is considered, as well as the experimental confirmation.Originality/valueNew structure of the spherical actuator's rotor and its advantages are presented.

Rotation Induced by Optical-Thermal Energy Conversion with Laser Irradiation under Molecular Gas Dynamics Conditions

The laser opto micro actuator induced by a laser beam is proposed. In the Intermediate region of molecular gas dynamics, the actuator is a small fluid machinery rotated by the molecular gas dynamics effect with the energy conversion from laser beam energy to thermal energy. In this paper the effects of supporting systems, rotor materials, laser powers on the rotational phenomena are discussed by experimental approach. The supporting systems of an actuator axis were changed to a permanent magnet for a radial bearing. Aluminum and glass were selected for the rotor materials. By the permanent magnet bearing and glass rotor the rotational rates of the actuator rotor are faster than the rate of the alumimum rotor by 2.5 times.