Micro-Assembly and Packaging of MEMS Using Optically Transparent Electrostatic Gripper

2004 ◽  
Author(s):  
Eniko T. Enikov ◽  
Lyubomir Minkov
Keyword(s):  
Control Algorithm ◽  
Position Control ◽  
Optical Systems ◽  
Micro Assembly ◽  
Assembly Cell ◽  
Control Computer ◽  
Potential Applications ◽  
Position Sensitive ◽  
Lift Off ◽  
Gripping Force

This paper describes the assembly experiments with a novel miniature assembly cell for micro-electromechanical systems (MEMS). The cell utilizes a transparent electrostatic gripper and uses several disparate sensing modalities for position control: computer vision for part alignment with respect to the gripper, a fiber-coupled laser, and a position sensitive detector (PSD) for part to assembly alignment. Assembly experiments indicate that the gripping force and stage positioning accuracy are sufficient for insertion of 500μm wide parts in 550 μm wide slots etched in silicon wafers. Details on the cell operation, the control algorithm used and their limitations are also provided. Potential applications of the developed assembly cell are assembly of miniature optical systems, integration of optoelectronics, such as laser diodes with CMOS, and epitaxial lift-off (ELO) of thin films used in optoelectronic devices.

scholarly journals Force-Free Control for Direct Teaching of a Surgical Assistant Robot End Effector with Wire-Driven Bidirectional Telescopic Mechanism

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3498
Author(s):  
Youqiang Zhang ◽  
Cheol-Su Jeong ◽  
Minhyo Kim ◽  
Sangrok Jin
Keyword(s):  
Control Algorithm ◽  
Position Control ◽  
Friction Model ◽  
Surgical Instruments ◽  
Control Input ◽  
End Effector ◽  
Motor Current ◽  
Direct Teaching ◽  
End Effectors ◽  
Teaching Operation

This paper shows the design and modeling of an end effector with a bidirectional telescopic mechanism to allow a surgical assistant robot to hold and handle surgical instruments. It also presents a force-free control algorithm for the direct teaching of end effectors. The bidirectional telescopic mechanism can actively transmit force both upwards and downwards by staggering the wires on both sides. In order to estimate and control torque via motor current without a force/torque sensor, the gravity model and friction model of the device are derived through repeated experiments. The LuGre model is applied to the friction model, and the static and dynamic parameters are obtained using a curve fitting function and a genetic algorithm. Direct teaching control is designed using a force-free control algorithm that compensates for the estimated torque from the motor current for gravity and friction, and then converts it into a position control input. Direct teaching operation sensitivity is verified through hand-guiding experiments.

scholarly journals Neural Network Based Contact Force Control Algorithm for Walking Robots

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 287
Author(s):  
Byeongjin Kim ◽  
Soohyun Kim
Keyword(s):  
Neural Network ◽  
Contact Force ◽  
Force Control ◽  
Control Algorithm ◽  
Position Control ◽  
Linear Quadratic Regulator ◽  
Walking Robots ◽  
Test Model ◽  
Linear Quadratic ◽  
Contact Force Control

Walking algorithms using push-off improve moving efficiency and disturbance rejection performance. However, the algorithm based on classical contact force control requires an exact model or a Force/Torque sensor. This paper proposes a novel contact force control algorithm based on neural networks. The proposed model is adapted to a linear quadratic regulator for position control and balance. The results demonstrate that this neural network-based model can accurately generate force and effectively reduce errors without requiring a sensor. The effectiveness of the algorithm is assessed with the realistic test model. Compared to the Jacobian-based calculation, our algorithm significantly improves the accuracy of the force control. One step simulation was used to analyze the robustness of the algorithm. In summary, this walking control algorithm generates a push-off force with precision and enables it to reject disturbance rapidly.

Smooth transition adaptive hybrid impedance control for connector assembly

2018 ◽  
Vol 45 (2) ◽  
pp. 287-299 ◽  
Author(s):  
Jun Wu ◽  
Fenglei Ni ◽  
Yuanfei Zhang ◽  
Shaowei Fan ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Position Control ◽  
Impedance Control ◽  
Estimation Error ◽  
Adaptive Controller ◽  
Smooth Transition ◽  
Reference Trajectory ◽  
Content Type ◽  
Dynamic Uncertainty ◽  
Force Tracking ◽  
Potential Applications

Purpose This paper aims to present a smooth transition adaptive hybrid impedance control for compliant connector assembly. Design/methodology/approach The dynamics of the manipulator is firstly presented with linear property. The controller used in connector assembly is inspired by human operation habits in similar tasks. The hybrid impedance control is adopted to apply force in the assembly direction and provide compliance in rest directions. The reference trajectory is implemented with an adaptive controller. Event-based switching strategy is conducted for a smooth transition from unconstrained to constrained space. Findings The method can ensure both ideal compliance behaviour with dynamic uncertainty and a smooth transition from unconstrained to constrained space. Also, the method can ensure compliant connector assembly with a good tolerance to the target estimation error. Practical implications The method can be applied in the connector assembly by “pushing” operation. The controller devotes efforts on force tracking and smooth transition, having potential applications in contact tasks in delicate environment. Originality/value As far as the authors know, the paper is original in providing a uniform controller for improving force and position control performance in both unconstrained and constrained space with dynamic uncertainty. The proposed controller can ensure a smooth transition by only adjusting parameters.

An Integrated Micro-Gripping System for the Assembly of Miniature Mechanical Structures

2011 ◽  
Vol 317-319 ◽  
pp. 750-756 ◽  
Author(s):  
Yuan Sun ◽  
Zhi Jing Zhang ◽  
Xin Ye ◽  
Xiao Feng Zhang ◽  
Yan Feng
Keyword(s):  
Real Time ◽  
Feedback Mechanism ◽  
Linear Motion ◽  
Micro Assembly ◽  
Micro Gripper ◽  
Different Shapes ◽  
Motion Stage ◽  
Gripping Force

The current developed micro-grippers are not effectively used in micro-assembly within the scale of 0.01-10mm due to some practical problems. In this paper, we present a novel integrated micro-gripping system. In this system, the vac-sorb gripper and the micro-gripper based on a linear motion stage are employed together to stably pick up miniature mechanical structures in different shapes and dimensions. The gripping force is detected in real time and used as a feedback to control the action of the system. The design of the system and the implementation of the feedback mechanism are described in details. Experiments are taken and analyzed and the results show the designed functionality of the system.

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