Hybrid Electromagnetic Actuator Research Articles

Intelligent switching control of hybrid electromagnetic active suspension based on road identification

The hybrid electromagnetic actuator integrates a magnetorheological damper, and a linear motor can effectively reduce the energy consumption of linear electromagnetic active suspension by switching the control parameters with the same dynamic performances. Thus, the intelligent switching control of hybrid electromagnetic active suspension (HEMAS) is investigated with a fast–slow switching method for full road conditions for the first time, which uses the road level and system state variables as the switching rules. First, the intelligent switching control system architecture of HEMAS is designed, and the switching logic is refined. Then, the modified skyhook control strategy is adopted, and the control parameters (including overfull and transient objective control parameters) are optimized for different driving conditions. Then, the simultaneous estimation method of road profile and system state variables and the identification method of road level are studied. The identification result is used as a prerequisite for intelligent switching of system control parameters. Last, a road adaptive intelligent switching control system is designed, and the stability of the switching system is analyzed. Furthermore, a hardware-in-the-loop bench test is performed. The test results verify the effectiveness of the intelligent switching control system in improving the comprehensive performances (dynamic and energy-saving performances) of HEMAS.

A Hybrid Electromagnetic and Tendon-Driven Actuator for Minimally Invasive Surgery

Minimally invasive surgery (MIS) is a surgical technique that facilitates access to the internal tissues and organs of a patient’s body via a limited number of small incisions or natural orifice of the patients. Such a technique requires specialized slender surgical instruments with a high levels of dexterity and functionality. However, the currently available MIS instruments are rigid and could offer only limited degrees of freedom (DOFs) that hampers the surgeon’s effort to perform the required operation accurately. In this study, we have developed a hybrid electromagnetic and tendon-driven actuator as an integral part of MIS surgical instruments to provide them with optimum angulation. The design uses a novel electromagnetic structure to lock the position of individual joints, and a tendon-driven structure for the articulation of the surgical instrument. The finite element method (FEM) was utilized to predict the performance of the actuator, which was experimentally validated. Subsequently, a prototype was assembled, and corresponding kinematics analysis was presented to visualize the improvement of the developed mechanism on the functional workspace of the MIS instruments. It was concluded that the developed mechanism could offer three additional DOFs for the surgical instrument and angulation of 180° for each articulated joint.

Mode-switching control and stability analysis of a hybrid electromagnetic actuator for the vehicle suspension

To coordinate the contradictory relationship between dynamic performances and electrical energy consumption of an electromagnetic active suspension, a hybrid electromagnetic actuator that integrates with a linear motor and a hydraulic damper is developed, which can achieve active control and energy regeneration compared with the linear electromagnetic actuator. A mode-switching control method is put forward based on the modified skyhook control. The stability of the switched controller with a specific switching rule is investigated based on the Lyapunov theorem. Then, the switching control system of a hybrid electromagnetic actuator is designed. Finally, a linear electromagnetic actuator and a passive damper are taken as comparison objects, and comparative bench tests, including a dynamic performance test and an energy consumption test, are conducted. The test results show that the hybrid electromagnetic actuator with mode-switching control can balance the dynamic performances and electrical energy consumption effectively.

Optimal Design and Experimental Research on a New Hybrid Electromagnetic Actuator for Vehicles

In this study, a new hybrid electromagnetic actuator (HEMA) that integrates a cylindrical permanent magnet linear synchronous motor and a hydraulic damper is proposed and designed to solve the problem of poor reliability of a linear electromagnetic actuator. A modified skyhook control that matches the structure of the HEMA is adopted, and the performance parameters are optimized. Then, the relationships among structural parameters of the HEMA are analyzed using equivalent magnetic circuit method. On the basis of these relationships, multiple alternative groups of structural parameters are obtained. Moreover, finite element models are established in Ansoft Maxwell software. The structural parameters of the HEMA are optimized and determined to produce the peak electromagnetic thrust force that the linear motor requires. Finally, a prototype is developed on the basis of the optimized results for the bench test. Test results show that the linear motor tracks the desired force effectively. In contrast to the passive damper, the body acceleration and suspension working space of HEMA are decreased by 20.6% and 13.3%, respectively. The dynamic tire load is increased by 16%, which is in a reasonable range. And compared with LEMA, the body acceleration is increased by 2.73%, but the suspension working space and dynamic tire load are reduced by 1.1% and 38.1%. All the results above mentioned demonstrate that the HEMA can considerably improve the vehicle dynamic performance.

A new hybrid electromagnetic actuator for a modified skyhook control strategy with energy reduction

This paper puts forward a modified skyhook control strategy for the electromagnetic suspension to improve the dynamic performance of the vehicle body and coordinate the wheel vibration simultaneously. The influence of control parameters (skyhook damping coefficient and passive damping coefficient) on the vehicle dynamic performances is analyzed, and the optimal values are determined. In addition, a new type of hybrid electromagnetic actuator which integrates a linear motor and a hydraulic damper is proposed to guarantee the reliability of electromagnetic suspension, and implement the modified skyhook control strategy. The structure parameters of the linear motor are optimized when the hydraulic damper is taken as a design basis, and the prototype is produced. Since the hybrid structure exactly matches the “hybrid damping” of the modified skyhook control strategy, the linear motor simply imitates the skyhook damping, which reduces the power demand compared with the electromagnetic suspension only with a linear motor. Then, the double loop control system for the hybrid electromagnetic actuator is designed. The external loop with a combined filter is utilized to obtain the body absolute velocity for the desired skyhook damping force, and the internal loop controls the linear motor to track the desired force with current hysteresis control. Finally, a comparative bench test is conducted, and the test results verify the effectiveness and control effect of hybrid electromagnetic actuator.

Energy consumption sensitivity analysis and energy-reduction control of hybrid electromagnetic active suspension

Abstract A hybrid electromagnetic active suspension (HEMAS), which integrates a linear motor and magneto-rheological damper, is considered a potential solution to address the high electrical energy consumption of electromagnetic active suspension. The control objectives of HEMAS for different driving conditions are determined according to the dynamic responses of passive suspension (PS). The sensitivity of dynamic performance and electrical energy consumption of HEMAS to controllable and uncontrollable parameters is analyzed for different control objectives. On this basis, the electrical energy-reduction mechanism and control method are obtained. A new hybrid electromagnetic actuator and its control system are designed. The PS and linear electromagnetic active suspension (LEMAS) are taken as comparison objects. A hardware-in-the-loop comparative test, including dynamic performance and energy-reduction tests, is performed. Test results show that in comparison with PS, the suspension working space and dynamic tire load of HEMAS on Grade B are reduced by 88.1% and 6.6%; the suspension working space and body acceleration on Grade D are reduced by 15.9% and 29.4%; and the body acceleration, dynamic tire load, and suspension working space are reduced by 18.3%, 3.7%, and 43.5% on Grade C, respectively. In comparison with LEMAS, the electrical energy consumption of HEMAS for three different roads is reduced by 45.9%, 44.2%, and 39.9%, which proves the effectiveness of HEMAS in coordinating the system dynamic performance and electrical energy consumption.

Automated Noncontact Micromanipulation Using Magnetic Swimming Microrobots

This letter reports an approach to automated microfluidic trapping and manipulation using a peanut-like magnetic-drive swimming microrobot of about 0.8- $\mu$ m diameter and 3 $\mu$ m in length. A hybrid electromagnetic actuator was developed to drive the microrobot in two motion modes: rolling and kayaking. The rolling mode can generate strong vortex flows for two-dimensional trapping and manipulation of a microparticle several hundred times the volume of the microrobot by pushing, pulling, and steering. Because of its weaker trapping force, kayaking mode is more effective for the release operation. A vision- and behavior-based controller is proposed to iteratively correct emerging manipulation behaviors for improved performance in complicated trajectory tracking and transportation of microparticles in complex environments. The experimental results demonstrate the capability and flexibility of the microrobot in trapping and transporting microparticles of up to 15- $\mu$ m diameter along trajectories defined by scattered points, even steering microparticle out of a micromaze along the automatically generated trajectory point by point.

A modified energy-saving skyhook for active suspension based on a hybrid electromagnetic actuator

This study proposes a modified energy-saving skyhook consisting of active control, energy regeneration, and switch. The modified skyhook coordinates the contradiction between dynamic performance and energy consumption of electromagnetic active suspension. The control principle is analyzed, the switch condition between active control and energy recovery is provided, and the switch control system is designed for simulation. Results demonstrate that the presented strategy can coordinate the dynamic performance and energy consumption effectively. The realization structure, namely, a hybrid electromagnetic actuator, is then designed to satisfy the control requirements. It integrates a linear motor and a hydraulic damper. The linear motor is used for active control or energy regeneration, while the hydraulic damper is used to guarantee basic dynamic performance. The structural dimension of hybrid electromagnetic actuator is optimized to increase air gap flux density with the volume and weight limitation. A prototype is fabricated, and a bench test is conducted. Results show that the structure can satisfy the control requirements. Some errors within a reasonable range are also observed between the test and the simulation because the simulation model is prepared under ideal conditions.

Actuator control for a new hybrid electromagnetic valvetrain in spark ignition engines

Valve timings of a spark ignition engine have been limited to a narrow range of alternatives within the constraints of the fuel economy, the emissions and the dynamic performance. Variable valve timing shows promise as a new key technology for improving the fuel consumption and emissions of spark ignition engines. Several techniques have been developed to perform variable valve timing, and the method with the most potential, called a hybrid electromagnetic valvetrain actuator, is an electromagnetic valvetrain with a permanent magnet and electromagnetic coils installed together. In this study, a novel hybrid electromagnetic valvetrain with a permanent magnet and electromagnetic coils, which significantly differs from existing electromagnetic valvetrains, was designed to overcome the drawbacks of conventional electromagnetic valvetrains that have been introduced previously. This new hybrid electromagnetic valvetrain is characterized by a simple structure, simple actuation and an ultra-low actuating power. Magnetic simulation was applied to analyse the magnetic flux density of the electromagnetic valvetrain and to optimize the design parameters. Dynamic simulation results show that the proposed hybrid electromagnetic valvetrain with soft-landing control can fully satisfy the valve dynamics in spark ignition engines. Additionally, the utilization of a permanent magnet and an optimal actuating current to catch and release valves has many advantages in energy consumption for valve catching and releasing when compared with other electromagnetic valvetrains.

미진동 저감을 위한 복합형 전자기식 작동기의 개발에 대한 연구

A hybrid electromagnetic actuator with an air mount is designed so as to achieve the desired isolation reduce the vibration efficiency on the floor vibration. The performance specification of the hybrid electromagnetic actuator is determined based on the vibration criterion for vibration-sensitive equipment. In the design stage of the electromagnetic actuator, the simple reluctance method is adapted to analyze magnetic circuits. The result is verified by finite element analysis using ANSYS Emag. Finally, in order to confirm the design performance, a dynamic characteristic test is carried out for the prototype of a hybrid electromagnetic actuator.

Research of Novel Hybrid-Electromagnetic Actuator with Adjustable Rigidity and Damping

A novel hybrid-electromagnetic actuator with the permanent magnet is designed, by which the operating component can realize the to-and-fro driving movement by changing the current direction of its control coil and it is more convenient to use for active vibration control. The electromagnetic force of the actuator is theoretically calculated by equivalent magnetic circuit and by the finite element respectively. Finally the characteristic of its rigidity and damping in an active vibration isolation system are analyzed, and it is indicated that they are not only related to its structure parameters，but also to the parameter of controller.

리니어 펌프 구동용 하이브리드 전자기 리니어 엑츄에이터 해석 및 설계

리니어 펌프 구동용 하이브리드 전자기 리니어 엑츄에이터를 해석하고 설계하였다. 솔레노이드 엑츄에이터는 기계적인 에너지 변환장치가 필요하지 않기 때문에 공간을 많이 차지하지 않는 이점으로 인해 널리 사용되고 있다. 또한 에너지 손실이 매우 낮고 소음이 발생하지 않는 장점을 가지고 있다. 하지만, 솔레노이드 엑츄에이터는 전력소비가 크다는 단점을 가지고 있다. 이런 단점을 보완하여 전력소비를 줄이기 위하여 영구자석을 활용한 새로운 하이브리드 전자기 리니어 엑츄에이터를 제안하고 향상된 성능을 검증하기 위해 동적 유한요소 분석을 통해 시뮬레이션을 수행하였다. The purpose of this paper is to analyze and design a new hybrid electromagnetic linear actuator for linear pumps. Solenoid linear actuator is widely used because it occupies small space due to no mechanical energy conversion system. In addition, the energy loss is very low and it has no noise. Conventional solenoid linear actuator, however, has the critical drawback of high power consumption. In this research, we present a new hybrid electromagnetic linear actuator using a permanent magnet in order to reduce power consumption. The enhanced performance of the hybrid linear actuator was verified by dynamic finite element analysis.