• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.44-44
• /
• 2007

New inchworm type piezoelectric actuator design, which can reduce the number of the piezoelectric body for manufacturing inchworm type actuator, is suggested in this work. Inchworm type actuator consists of three or more piezoelectric bodies, on the other hand the new-designed inchworm type actuator has only one piezoelectric body. The one piezoelectric body that size is $2\;{\times}\;2\;{\times}\;4\;[mm^2]$ (DWL) has 2 clamping part and 1 extending part. The size of the new-designed actuator with one piezoelectric body is $5\;{\times}\;6\;{\times}\;9\;[mm^2]$ (DWL). The new-designed inchworm type actuator performed the operation at a cycle (6 steps) of $0.3{\mu}m$ per $33.3{\mu}s$ and a generated force of 0.6N.

• The Journal of Korea Robotics Society
• /
• v.2 no.2
• /
• pp.178-182
• /
• 2007

Precision stages are essential device for micro machines, fiber optic assembly systems, and biology instruments. In this paper, a precision inchworm type actuator for a linear stage is proposed and evaluated. An analytic method to design an inchworm type motor is proposed. Developed actuator provides fast motion compared with a commercial inchworm actuator, and can be used as an actuator for a stage in substitution for a conventional rotary actuator.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.843-848
• /
• 2000

In general, inchworm actuators are composed of two clamping piezoelectric elements and one expansion piezoelectric element. In this paper, two electromagnetic clampers are used for higher speed and high load. Dynamic equation is derived to simulate the behavior of the inchworm actuator with electromagnets. Electromagnetic clamper is used to improve the performance of the inchworm actuator. The electromagnetic clamper is composed of two permanent magnets and one traditional electromagnet. The permanent magnets play the role of the source of magnetic field to make clamping force higher, and the electromagnet is to change the mode between clamping and free. The driving voltage profile is also analyzed to improve the speed of inchworm actuator. The real system was manufactured and experimented to find dynamic characteristics and the maximum speed is obtained. Dynamic model is verified by comparing with experimental results.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.18 no.2
• /
• pp.137-143
• /
• 2009

This paper presents the fabrication of inchworm motor for high precision actuator system of large displacement and high force. The inchworm motor consists of a extend actuator that provides displacement of tool guide and two clamping actuators which provide the holding force. In order to avoid the PZT fracture, design of pre-load housing was conducted by flexure hinge structure, because PZT actuator has low tensile and shear. To design the pre-load housing and optimize the clamping mechanism, the static and dynamic analysis were conducted by finite element method. From these results, a prototype of the inchworm motor was fabricated and dynamic characteristic with respect to the various frequency was tested. The maximum velocity of the inchworm motor was $41.1{\mu}m/s$ at 16Hz.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.8
• /
• pp.685-690
• /
• 2007

The new design of inchworm-type piezoelectric actuator is presented in this paper, Compared to conventional inchworm-type actuators, which are composed of more than three piezoelectric bodies, we can reduce the number of piezoelectric bodies by employing the proposed design, resulting in only one piezoelectric body. The overall size of the proposed actuator which consists of one piezoelectric body, two clamping parts and one extending part, is only $5{\times}6{\times}9 [mm^3]$ (DWL). The actuating characteristics of fabricated Monolithic Inchworm Type Actuator(MITA), were found to be a displacement of $0.3{\mu}m$, a generating force of 0.6N and an electric power of 0.5W.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.1088-1091
• /
• 1997

This paper describes the characteristic of hinges on which a lever pivots within a limited angle due to the torque. The hinges are exerted by the thermally expanded actuators connected with a level through hinges. To enhance the stroke of inchworm actuator, FEM(Finite Element Method) was utilized for the characterization in view of stress displacement according to the variation of notch radius and notch width. As a result, notch width of the hinges plays an important part in improvement of micro inchworm actuator.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.7 s.100
• /
• pp.878-884
• /
• 2005

This paper presents an algorithm for the precision motion control based on the dynamic characteristics of piezoelectric actuators in the inchworm. The dynamic characteristics are identified by the frequency domain modeling technique using the experimental data. For the motion control, the hysteresis behavior is compensated by the inverse hysteresis model. The dynamic stiffness of an inchworm is generally low compared to its driving condition, so mechanical vibration may degenerate the motion accuracy of the inchworm. The Sliding mode controller and the Kalman filter are designed for motion control of the inch-worm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.630-637
• /
• 2003

This paper proposes a new modeling scheme to describe the hysteresis and the dynamic characteristics of piezoelectric actuators in the inchworm and develops a control algorithm for the precision motion control. From the analysis of piezoelectric actuator behaviors, the hysteresis can be described by the functions of a maximum input voltage. The dynamic characteristics are also identified by the frequency domain modeling technique based on the experimental data. For the motion control, the hysteresis behavior is compensated by the inverse hysteresis model. The dynamic stiffness of an inchworm is generally low compared to its driving condition, so mechanical vibration may degenerate the motion accuracy of the inchworm. Therefore, the sliding mode control and the Kalman filter are developed for the precision motion control of the inch-warm. To demonstrate the effectiveness of the proposed modeling schemes and control algorithm, experiment validations are performed.

• International Journal of Precision Engineering and Manufacturing
• /
• v.6 no.2
• /
• pp.34-39
• /
• 2005

The precision stage is an essential device for optic fiber assembly systems, micro machines and semiconductor equipments. A new piezoelectric inchworm type actuator is proposed to implement an actuator-integrated long-stroke linear stage. An in-and-quadrature phase (I/Q) heterodyne interferometer is developed as a feedback sensor of a servo system, and a synchronized counting method is proposed. The proposed measurement system can measure the accurate position of fast moving object with robustness to external sensing noise from actuator vibration. The developed servo stage will be applied to optic fiber device assembly system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2005.05a
• /
• pp.458-461
• /
• 2005

In this paper, a new type of inchworm motion actuator is developed in fabrication of actuators for micro-press machine. This is consisted of three piezoelectric actuators, one is for moving the tool guide and the other are for clamping the guide. The inchworm motor provides both high load and large displacement in small size actuator. PZT has compressive strength and often fails under tensile stress and pulling. Thus, in order to prevent failure, we have designed pre-load housing and accomplished FEM analysis. The pre-load housing was used for determining the optimal design condition by comparing the von-mises stresses with the change of hinge stiffness. Also, in order to predict the performance of the motor under certain conditions, the system model was simulated using MATLAB. This is open loop control actuator and driven by the period of input voltage.