Eddy-current losses in laminated and solid steel stator back iron in a small rotary brushless permanent-magnet actuator

The ever-increasing necessity to miniaturize smooth torque rotary actuators has placed severe constraints on the current slotless permanent-magnet technology. These constraints are mainly the consequence of the relatively large effective magnetic airgap which limits the achievable magnetic loading and, therefore, the torque density of slotless permanent-magnet rotary actuators. Further, the miniaturization has to be achieved at ever-decreasing costs and, therefore, it would be advantageous to implement solid back irons. However this, even at reduced magnetic loading, still results in considerable eddy-current losses. Therefore, a careful selection of the various actuator dimensions and most appropriate soft magnetic laminated or solid material is a prerequisite for applications that require smooth speed and torque characteristic. This paper will identify the influence of various parameters of the slotless permanent-magnet actuator on the eddy-current loss in the back iron using both 2-D and 3-D finite-element analysis

Modeling and experimental verification of a tubular actuator for 20-g acceleration in a Pick-and-Place Application

This paper presents the modeling and the experimental verification of a tubular actuator for a pick-and-place application. To increase the throughput of a placement robot for printed circuit boards, a very fast linear motion is required. A moving-magnet tubular actuator with axially magnetized magnets is selected. Using a semianalytical magnetic field model coupled to a thermal one, a design is created that achieves a translator acceleration of 20 g. A prototype of the designed actuator is built and coupled with a Simulink dSpace system to perform extensive measurements in order to validate the models and investigate the achievable acceleration within a predetermined motion profile. The electromotive force is measured, and the disturbance forces are identified. The position error is measured during the motion profile with an acceleration of 20 g and a stroke of 30 mm. Furthermore, thermal measurements are performed to check the achievable duty cycle. The built design shows good agreement with the models, and the specified acceleration of 20 g is achieved

Three-dimensional magnetic field modeling of a cylindrical Halbach Array

A semi-analytical description of the 3-D magnetic field distribution of a cylindrical quasi-Halbach permanent magnet array is derived. This model avoids the necessity of time-consuming finite element analyses and allows for fast parameterization to investigate the influence of the number of segments on the magnetic flux density distribution. The segmented magnet is used to approximate an ideal radial magnetized ring in a cylindrical quasi-Halbach array. The model is obtained by solving the Maxwell equations using the magnetic scalar potential and describes the magnetic fields by a Fourier series

Design and control of magnetic bearings for rotary-linear motion applications

In this paper, an analytical model of a homopolar magnetic bearing, based on a magnetic equivalent circuit (MEC), is developed. Comparison with a three-dimensional finite element (FE) model of the magnetic bearing shows that the accuracy of the developed MEC is acceptable. Therefore, the MEC can be used for the investigation of aspects such as stiffness and force linearity of the magnetic bearing, which are crucial in the design phase of a magnetic bearing. In addition, a prototype consisting of two magnetic bearings and a shaftis built for the verification of the concept applied to a rotary-linear motion system. Closed loop identifica tion performed on the experimental setup reveals the expected dynamics of the designed magnetic bearings as well as additional dynamics which are not taken into account in the design

Constant force linear permanent magnet actuators

In applications, such as vibration isolation, gravity compensation, pick-and-place machines, etc., there is a need for (long-stroke) passive constant force actuators combined with tubular permanent magnet actuators to minimize the power consumption, hence, passively counteract the gravitational forces. For example, in pick-and-place machines, the passive devices allow the powerless counteraction of nozzles or tooling bits. In these applications, an increasing demand is arising for high-speed actuation with high precision and high bandwidth capability mainly due to the placement head being at the foundation of the motion chain, hence, a large mass of this device will result in high force/power requirements for the driving mechanism (i.e. an Hbridge three linear permanent magnet motors placed in an H-configuration. This paper investigates the combined constant-force with tubular actuator topology, where the two actuator topologies are separately introduced and the combination is verified using comprehensive three dimensional (3D) finite element analyses

Moving device as well as a component placement device provided with such a moving device

Samenvatting van US 2011194923 (A1) A moving device comprises at least a first element provided with main magnets and a second element provided with coils. The main magnets are arranged in a grid of rows and columns, wherein main magnets in adjacent rows are oppositely polarised and staggered relative to each other. The coils can be energized for moving the first element relative to the second element in a direction parallel to the rows as well as in a direction parallel to the columns. Auxiliary magnets of the same polarity are disposed between the main magnets at least in a number of rows, wherein the strength of the magnetic field of said auxiliary magnets is different from that of the main magnets

Moving device as well as a component placement device provided with such a moving device

Samenvatting van US 2011194923 (A1) A moving device comprises at least a first element provided with main magnets and a second element provided with coils. The main magnets are arranged in a grid of rows and columns, wherein main magnets in adjacent rows are oppositely polarised and staggered relative to each other. The coils can be energized for moving the first element relative to the second element in a direction parallel to the rows as well as in a direction parallel to the columns. Auxiliary magnets of the same polarity are disposed between the main magnets at least in a number of rows, wherein the strength of the magnetic field of said auxiliary magnets is different from that of the main magnets

Tech United Eindhoven Middle size league winner 2016

\u3cp\u3eThe Tech United Eindhoven Mid-size league (MSL) team won the 2016 Championship in Leipzig. This paper describes the main progress we made in 2016 which enabled this success. Recent progress in software includes improved perception methods using combined omnivision of different robots and integrating the Kinect v2 camera onto the robots. To improve the efficiency of shots at the opponents’ goal, the obstacle detection is improved. During the tournament new defensive strategies were developed as an answer to the advanced attacking strategies that were seen during the round robins. Several statistics of matches during the tournament show the overall performance of Tech United at RoboCup 2016.\u3c/p\u3