• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.155-161
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• 2006

This paper introduces a new type of mechanical tape feeder for chip mounter. The mechanical feeder is composed of a pneumatic linear actuator and a linear feeding module with the application of a cam-slider. As semiconductor chips are getting smaller, PCB assembly makers require the feeder to position the chip with high accuracy. The linear feeding system improves the positioning accuracy of the chip by getting rid of the index error, which brings into existence on the sprocket rotating feeder. It also can make greatly reduce the dumping rate. The dumping error is caused by the impact occurred as the pawl to interrupt ratchet wheel rotation. The paper discusses its mechanism and mechanical performance. The positioning accuracy and the dynamic characteristic were measured for long time operation and analyzed. As a result, the feeder showed very good performance. However, the feeding system was dynamically unstable due to the cover film eliminator that is required to be modified

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.357-360
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• 1997

Abstract: In teleoperation field robotic system such as hydraulically actuated robotic excavator, the maneuverability and convenience is the most important part in the operation of robotic excavator. Particularly the force information is important in dealing with digging and leveling operation in the teleoperated excavator. Excavators are also subject to a wide variation of soil-tool interaction forces. This paper presents a new force reflecting joystick in a velocity-force type bilateral teleoperation system. The master system is electrical joystick and the slave system IS hydraulically actuated cylinder with linear position sensor. Particularly Pneumatic motor is used newly in the master joystick for force reflection and the information of the pressure of salve cylinder is measured and utilized as the force feedback signal. Also force-reflection gain greatly affects the excavation performance of a hydraulically actuated robotic system and it is very difficult to determine it appropriately since slave excavator contacts with various environments such as from soft soil to rock. To overcome this, this paper proposes a force-reflection gain selecting algorithm based on artificial neural network and fuzzy logic.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.321-324
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• 2007

The actuators of anti-vibration system(AVS) can be separated into several types: piezoelectric actuators, pneumatic springs, cylinders, rotating motor and linear motor. The last one has some advantages, such as low noise, low vibration, simpler configuration and possibility of direct drive. The voice coil motor(VCM) is one type of linear motor, originally used in speaker system. VCM actuators are usually used in occasions that rapid and controlled motion of devices are required. In this paper, a controller which satisfies system specification(e.g. current controller bandwidth) within whole operation range is designed. For that objective, parameters as position were initially obtained with 3D FEM analysis and motor modeling was performed. A current controller in 2-axis VCM drive system was designed and then performance of the proposed controller was verified with simulation using Simplorer and an experimental result.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.4 s.181
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• pp.132-138
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• 2006

A tape feeder is an important part to supply a micro chip such as 1005 and 0603 components in SMT process. Traditional sprocket wheel type feeder has several problems such as backlash and indexing errors, low compatibility and confidence. However, it is very difficult to solve such problems due to the inevitable fraction defectives of sprocket wheel. Thus, the object of this works is to develop a linear type high precision tape feeding system using cam-slider mechanism. The proposed cam-slider mechanism is composed of several links and a plate, pneumatic actuator is used to generate linear motion. The proposed mechanism has distinct advantages over the conventional mechanism. It has reduced feeding errors, long lift-cycle, and slim width. As a result, the developed tape feeder using cam-slider mechanism shows special characteristics far high precision feeding for chip-mounters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.771-782
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• 2017

This paper describes the development of a wearable robot to assist ankle power for the elderly. Previously developed wearable robots have generally used motors and gears to assist muscle power during walking. However, the combination of motor and reduction gear is heavy and has limitations on the simultaneous control of stiffness and torque due to the friction of the gear reducer unlike human muscles. Therefore, in this study, Mckibben pneumatic muscle, which is lighter, safer, and more powerful than an electric motor with gear, was used to assist ankle joint. Antagonistic actuation using a pair of pneumatic muscles assisted the power of the soleus muscles and tibialis anterior muscles used for the pitching motion of the ankle joint, and the model parameters of the antagonistic actuator were experimentally derived using a muscle test platform. To recognize the wearer's walking intention, foot load and ankle torque were calculated by measuring the pressure and the center of pressure of the foot using force and linear displacement sensors, and the stiffness and the torque of the pneumatic muscle joint were then controlled by the calculated ankle torque and foot load. Finally, the performance of the developed ankle power assistive robot was experimentally verified by measuring EMG signals during walking experiments on a treadmill.