• Proceedings of the KWS Conference
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• 2005.06a
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• pp.63-65
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• 2005

Because of simple principal and low cost, resistance spot welding has been used a lot for joining the sheet metal in automotive manufacturing process. Welding current, welding time, and force are the most important variables in resistance spot wording. Air guns have hem still used widely. The requirement of synchronizing between robot and weld-gun has become bigger as the field has been automated. The number of servo-gun in the field is trending upward because there're advantages as like to synchronize with robot and to control the stroke path and force by programming on servo-gun system. But no cleared force control method is suggested on servo-gun system until now. In this study, we proved the feedback current of the servo-motor can be used to an excellent force measuring sensor and the force is controlled by the feedback current. And we also detected force lowering during welding cycle on the servo-gun system and solved by compensated force control.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.4
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• pp.123-129
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• 2001

Recent requirements for the fast and accurate motion in industrial robot manipulators need more advanced control tech-niques. To satisfy the requirements, importance of force control is being continuously increased and the expensive force sensor is usually installed to obtain the contact force information in practice. This information is indispensable for the force control of maintaining the desired contact force. However, the sensor cost is too high to be used in industrial applications. In this paper, it is proposed to estimated the contact force occurring between the end-effector of 2 DOF robots and environ-ment. The contact force estimation system is developed based on the static and dynamic models of 2 DOF robot manipula-tors. where the contact force is described with respect to the link torque. The Extended Kalman Filter is designed and its performance is verified in simulations.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.14-19
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• 2000

Recent requirements for the fast and accurate motion in industrial robot manipulator need more advanced control techniques. To satisfy the requirements, importance of the force control is being continuously increased and the expensive force sensor is usually installed to obtain the contact force information in practice. This information is indispensable for the force control of maintaining the desired contact force. However the sensor cost is too high to be used in industrial applications. In this paper, it is proposed to estimate the contact force occurred between the end-effector of 2 DOF robots and environment. The contact force estimation system is developed based on the static and dynamic models of 2 DOF robot manipulators, where the contact force is described with respect to the link torque. The Extended Kalman Filter is designed and its performance is verified in simulations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.2
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• pp.192-197
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• 2001

Recent requirements for the fast and accurate motion in industrial robot manipulators need more advanced control techniques. To satisfy the requirements, importance of the force control is being continuously increased and the expensive force sensor is often installed to obtain the contact force information in practice. This information is indispensable for the force control of maintaining the desired contact force. However, the sensor cost is too high to be used in industrial applications. In this paper, it is proposed to estimate the contact force occurred between the end-effector of robots and environment in 3-D. The contact force monitoring system is developed based on the static and dynamic models of 3 DOF robot manipulators, where the contact force is described with respect to the link torque. The Extended Kalman Filter is designed and its performance is verified in simulations.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.127-134
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• 2012

Stroke patients must do the rehabilitation exercise to recover their fingers' function using a rehabilitation robot. But the rehabilitation robots mostly have not the force sensors to control the applied force to each finger. Thus, in this paper, the development of a force sensor for thumb rehabilitation robot and four two-axis force sensors for four-finger rehabilitation robot were developed. The force sensor and four two-axis force sensors could be used to measure the applied force to each finger, and the forces could be used to control the applied forces to each sensor in rehabilitation exercise using in the rehabilitation robot. The developed sensors have non-linearlity error of less than 0.05 %, repeatability error of less than 0.03 %, and the interference error of two-axis force sensor is less than 0.2 %.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.3
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• pp.226-232
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• 2016

This paper describes the design of a smart three-axis force sensor for measuring forces Fx, Fy and Fz. The smart three-axis force sensor is composed of a three-axis force sensor, a force-measuring device, housing and a cover, where the three-axis force sensor and the force-measuring device are inside the housing and the cover. The measuring device measures forces Fx, Fy and Fz from the three-axis force sensor, and calculates the resultant force using the measured forces, and then sends the resultant force and forces to a PC or other controller using RS-485 communication. The repeatability error and the non-linearity error of the smart three-axis force sensor are less than 0.03%, and the interference error of the sensor is less than 0.87%. It is thought that the sensor can be used for measuring forces in a robot, automatic systems and so on.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.524-529
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• 2016

We describe the design and fabrication of a two-axis force/torque sensor with parallel-plate beams (PPBs) and single beams for measuring force and torque in hip-joint rehabilitation exercise using a lower rehabilitation robot. The two-axis force/torque sensor is composed of an Fz force sensor and a Tz torque sensor, which detect z direction force and z direction torque, respectively. The two-axis force/torque sensor was designed using the FEM (Finite Element Method) and manufactured using strain gages. The characteristics experiment of the two-axis force/torque sensor was carried out. The test results show that the interference error of the two-axis force/torque sensor was less than 0.64% and the repeatability error and the non-linearity of the two-axis force/torque sensor were less than 0.03%. It is thought that the developed two-axis force/torque sensor could be used for a lower rehabilitation robot.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1169-1172
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• 1995

In this paper, the external force control and hybrid force control algorithms are proposed to apply Deburring process. the purpose of adjust which can be implemented to on unknown environments, adaptive control law(MRAC) is adopted. IF a model system is given, the plant system can be controlled on the way which we will introduce to. We showed the validation and the possibility of Deburring process with multi-dimensional force control through experiments. the experimental result show the validity of Deburring in the robot manipulator.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.1
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• pp.61-66
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• 1997

로보트 매니퓰레이터가 일정한 접촉 힘을 유지하며 공작물의 표면을 따라가게 하는 작업은 많은 자동화 생산공정에서 유용하게 이용될 수 있다. 일반적인 위치제어용 산업용 로보트를 이러한 공정에 사용하기 위해서는 접촉힘이 계측되어 로보트의 제어에 이용되어야만 한다. 이 연구는 accommodation force control 방식으로 산업용 로보트를 제어하여 edge-following에 응용하도록하며, 접촉 힘의 계측에는 wrist force sensor를 사용한다. 이 시스템의 궤도추적속도와 force regulation 등이 예견제어에 의해 향상될 수 있다. 예견제어에 의해 설계된 전체 제어 시스템은 feedback 제어기와 feedforward 예견제어기로 구성된다. 여기서, 시스템의 안정성은 feedback 제어기에 의해서 결정되며, 예견제어기는 시스템에 미치는 외란을 통제하는 것을 주 기능으로 한다. 일반적으로 선형제어 방식을 채택한 경우와 예견제어를 이용한 edge-following을 실험을 통해 비교함으로써, 예견제어의 효용성을 확인한다.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.3
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• pp.173-180
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• 2015

In this paper, we propose a new precise control technology of robotic gripper for assembling and handling of part. When a robot manipulator interacts mechanically with its environment to perform tasks such as assembly or edge-finishing, the end-effector is thereby constrained by the environment. Therefore grasping force control is very important, since it increases safety due to monitoring of contact force. A comparison of various force control architecture is reported. Different force control methods can often be configured to achieve similar results for a given task, and the choice of control algorithm depends strongly on the application or on the characteristics of a particular robot. In the research, the adjustable gripping force can be controlled and improved the accuracy using the artificial intelligence techniques.