Linear-to-rotary motion converter using asymmetric compliant mechanics and single-crystal PMN-PT stack actuator

Na, Tae-Won,Kang, Dae-Hyun,Jung, Jin-Young,Han, Jae-Hung,Oh, Il-Kwon SAGE Publications 2014 Journal of intelligent material systems and struct Vol.25 No.18

<P>In this article, we report a novel linear-to-rotary motion converter that employs a single-crystal 0.71Pb(Mg<SUB>1/3</SUB>Nb<SUB>2/3</SUB>)O<SUB>3</SUB>-0.29PbTiO<SUB>3</SUB> (PMN-29PT) (PMN-29PT ) stack actuator and asymmetric compliant mechanics for flexural hinges. This unique motion converter is compact, economical to fabricate and has the capacity to be utilized in small-scale applications. The linear-to-rotary motion converter prototype was designed and fabricated using a seven-bar linkage kinematic model. Additionally, compliant mechanics at flexural hinges were used in place of conventional revolute joints. The converter consists of a stack actuator and a structural mechanism, including flexural hinges and a pivot hinge to convert linear motion to rotary motion. To determine the feasibility of the mechanism design and to estimate the accurate rotational motion of the designed converter, numerical simulations utilizing COMSOL Multiphysics 4.3 and experimental validation were performed by evaluating the displacement of the stack actuator and the rotational angle of the linear-to-rotary motion converter according to the changes of driving voltages. The experimental results show that the linear-to-rotary motion converter can produce a rotation angle of 1.52° at an input voltage of 900 V. The unique linear-to-rotary motion converter design proposed here can be applied to various engineering fields, instead of existing mechanical linear-to-rotary mechanisms, due to the advantages in compact size and precise control.</P>

Evaluation of Structural Safety of Electro-Mechanical Linear Actuator and Load Simulator with Plate Spring

김동협,김영철,김상우,이종환 항공우주시스템공학회 2020 항공우주시스템공학회지 Vol.14 No.6

This study investigated the structural behaviors and safety of an electro-mechanical linear actuator and a load simulator with a plate spring. The material and dimensions of the plate spring were determined by theoretically calculating the stress and torsional angle for the rating load of the actuator. Thereafter, a flexible multibody dynamics (FMBD) analysis was conducted on the linear actuator and load simulator to confirm the performance of the load simulator and acquire the reaction forces acting on the actuator and simulator. The structural safety of the linear actuator and load simulator was evaluated via finite element analysis using the aforementioned reaction forces. Consequently, the proposed linear actuator and load simulator were determined to be structurally safe; however, the safety factors for the actuation rod and the housing on the actuator were excessively high. Therefore, the weight and cost must be reduced to improve their design parameters in the future.

A novel design of active accelerator pedal using linear electromagnetic actuator

Lee, Jae-Yong,Kim, Jin-Ho,Woo, Sang-Min,Lee, Jeh-Won 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1

This paper describes a novel design of an active accelerator pedal(AAP) using a linear electromagnetic actuator that transfers warning messages recognized by the automobile from the sensors to the driver. In an emergency driving situation, the electromagnetic actuator creates additional pedal forces such as active pedal force and vibration force. In a passive situation however, the actuator does not produce additional force. In the past, a system with a rotary actuator was developed for AAP but was found to have critical drawbacks such as inaccurate movement by backlash and torque occurrence due to the high gear ratio. This research, therefore, aims to solve these drawbacks and maximize car safety by optimizing the electromagnetic linear actuator. Finite element analysis is performed to analyze the coupled system of electric, magnetic, and mechanical subsystems, and to characterize the dynamic performance of the proposed actuator system. A novel design of the AAP system with the optimized electromagnetic linear actuator is developed. The dynamic characteristics of the AAP system are simulated by a 3D dynamic analysis software program. Satisfactory results were obtained. Finally, the test result and the simulation result of the AAP system are compared.

Analysis Grasp Stability for Multi-fingered Robot Hand

Eun-Hye Kim,Myo-Taeg Lim,Yong-Kwun Lee 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

This paper describes grasp stability for a multi-fingered robot hand, called the KIST hand. The robot hand has controlled by four under-actuated fingers with totally nine DOFs, which are controlled by two linear actuators and linkage knuckles. This mechanism is able to generate high power compare to common robot hands that use rotary actuators. The robot hand has four tactile sensors which are attached to the fingertips on the each finger. The each tactile sensor can independently measure the contact force between the robot hand and an object. Using the tactile sensors, various objects can be grasped, such as a small tennis ball, a plastic ball and a rubber ball. In the former part of the paper, the mechanical design of the robot hand is presented. In the latter part of the paper, the control algorithm is described, and the analysis of grasp stability is confirmed by the experimental result.

가사지원용 인체모방 고효율 로봇핸드

김은혜(Eun-Hye Kim),이용권(Yong-Kwun Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

This paper describes a development of bio-mimetic robot hands and its control scheme. The robot hand has controlled by four under-actuated fingers with totally nine DOFs, which are controlled by two linear actuators and linkage knuckles. This mechanism is able to generate high power compare to common robot hands that use rotary actuators. The robot hand has four tactile sensors which are attached to the fingertips on the each finger. The each tactile sensor can independently measure the contact force between the robot hand and an object. Using the tactile sensors, various objects can be grasped. In the former part of the paper, the mechanical design of the robot hand is presented. In the latter part of the paper, the grasping control is described.

A Dexterous Robot Hand with a Bio-mimetic Mechanism

김은혜,이석원,이용권 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.

This paper describes a development of bio-mimetic robot hand and its control scheme. This robot hand has four independently moving fingers, which are driven by four-coupled link mechanism with two linear actuators. By using the linear actuators, we make the hand similar to human hand in its structure and motion. The coupled link mechanism makes the hand compact in structure and efficient in power. The robot hand is designed considering the dexterity and the compact size suited for various tools and objects in daily life. The hand has tactile sensors mounted on the palm and the fingertips at each finger. With tactile sensor based feedback control and force closure method, the paper shows the control of the robot hand which is very stable in grasping and handling various objects.

기립 및 보행 보조 휠체어의 개발

송찬양(Chan Yang Song),윤효준(Hyo Joon Yoon),이치범(Chibum Lee) 한국생산제조학회 2013 한국생산제조학회지 Vol.22 No.3-1

Until recently, the primary users of wheelchairs were people with lower body disabilities. However, the number of patients recovering from accidents or surgery, as well as the number of elderly people using wheelchairs, is constantly increasing. This study examined the design and manufacture of standing and gait assist wheelchairs that assist temporary gait disturbed patients to take rehabilitation training and elderly people to engage in walking exercise. A kinematic analysis was used to select a drive motor and design a four-bar linkage mechanism for lifting the backrest vertically. Using a multibody dynamic simulation, detailed design was performed taking into consideration the spatial motion and partial interference, and the necessary push force and stroke of the linear actuator were also calculated. To ensure structural safety, the von-Mises equivalent stresses of the upper and lower brackets of the linear actuator were verified through a finite element analysis. The manufactured wheelchair was shown to operate successfully as intended, using the developed controller for the drive motors and linear actuator.

기립 및 보행 보조 휠체어의 개발

송찬양,윤효준,이치범 한국생산제조학회 2013 한국생산제조학회지 Vol.22 No.3

Until recently,the primary users of wheelchairs were people with lower body disabilities. However, the number of patients recovering from accidents or surgery, as well as the number of elderly people using wheelchairs, is constantly increasing. This study examined the design and manufacture of standing and gait assist wheelchairs that assist temporary gait disturbed patients to take rehabilitation training and elderly people to engage in walking exercise. A kinematic analysis was used to select a drive motor and design a four-bar linkage mechanism for lifting the backrest vertically. Using a multibody dynamic simulation, detailed design was performed taking into consideration the spatial motion and partial interference, and the necessary push force and stroke of the linear actuator were also calculated. To ensure structural safety, the von-Mises equivalent stresses of the upper and lower brackets of the linear actuator were verified through a finite element analysis. The manufactured wheelchair was shown to operate successfully as intended, using the developed controller for the drive motors and linear actuator.

지능형 능동 가속 페달의 원통형 선형 액추에이터 설계 및 해석

이재용(Jae-Yong Lee),김진호(Jin-Ho Kim),이재원(Jeh-Won Lee),이정훈(Jung-Hun Lee),한승철(Seung-Chul Han) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

This paper has described a design and analysis of a tubular linear actuator for intelligent AAP(Active Accelerate Pedal) system. In AAP system, an electromagnetic actuator occurs the thrust force as a warning of accident in order to release driver's foot on the accelerate pedal. At emergency situation during driving, the electromagnetic actuator creates the additional pedal force such as active pedal force and vibration force. On passive situation, the actuator doesn't make the additional force. The AAP system with rotary actuator has the critical drawback such inaccurate movement generated by backlash and torque due to high gear ratio. This research, therfore, proposes the electromagnetic tubular actuator AAP system to overcome inherent drawback of rotary actuaotor AAP system and maximize the safety of cars. Electromagnetic finite element analysis is executed to analyze and design the tubular actuator and dynamic analysis is done to characterize dynamic performance of AAP system with designed tubular actuator according to two types of thrust force.

A flexure-based linear motion stage with parallel actuation mechanisms driven by piezo actuators

Kee-Bong Choi,Jae Jong Lee,Gee-Hong Kim,Hyung Jun Lim 한국생산제조학회 2012 한국생산제조시스템학회 학술발표대회 논문집 Vol.2012 No.10