H. Canbolat

A Novel Level Measurement Technique Using Three Capacitive Sensors for Liquids

The liquid level in a tank should be measured for most applications. In this paper, a new capacitive method is presented to detect the liquid level. Existing methods are generally approximations based on the large difference between the dielectric constants of the liquids and the air. The method proposed here eliminates the effect of air and gives the accurate reading of the liquid level in the tank. The main advantage of the method is that it can directly be applied to any kind of nonconductive liquid without calibration. The method is based on the measurements of capacitances of three parallel plate capacitive structures, which are designated as level, reference, and air sensors. It is mathematically proven that the method completely eliminates different factors, which affect the readings, such as air and temperature. The capacitance measurements are performed using a capacitance-to-digital converter integrated circuit, which can measure very small capacitances up to plusmn4 fF error. The result of a computer simulation, which demonstrates the performance and limitations of the proposed structure, is also provided.

Boundary control of a cantilevered flexible beam with point-mass dynamics at the free end☆

In this paper, we develop boundary controllers for a cantilevered Euler-Bernoulli beam with point-mass dynamics at the free end. Specifically, we develop an exact model knowledge controller which exponentially stabilizes the beam displacement and an adaptive controller which asymptotically stabilizes the beam displacement. Experimental results are utilized to validate the performance of the controllers.

Adaptive Boundary Control of Out-of-Plane Cable Vibration

This paper develops active controllers for the out-of-plane vibration of a flexible cable using boundary actuators and sensors, An exact model knowledge controller exponentially stabilizes the cable displacement assuming known system parameters. An adaptive controller asymptotically stabilizes the cable displacement while compensating for parametric uncertainty in the actuator mass and cable tension. The performance of the controllers is experimentally demonstrated.

Simulation of a SCARA robot with PD and learning controllers

Abstract In this study, a SCARA robot manipulator is simulated under PD and learning based controllers. The trajectory following performance of the robot is studied against these controllers. The adaptive/learning hybrid controller scheme and learning controller method are utilized as learning based controllers. The results of simulations show that, learning algorithm based controllers reduce the position tracking error effectively. The hybrid adaptive/learning controller has similar performance as the learning controller although it uses partial state information and compensates both mechanical and electrical dynamics, whereas the learning controller needs both position and velocity measurements neglecting electrical dynamics.

Adaptive position/force control of BDC-RLED robots without velocity measurements

This paper considers the problem of controlling the position and force of a constrained rigid-link electrically-driven robot manipulator actuated by brushed DC motors (BDC-RLED robot). Based on inexact knowledge of almost all of the system parameters and the lack of link velocity measurements, the integrator backstepping approach is used to design a voltage-level, adaptive position/force controller which ensures semi-global asymptotic tracking for the end-effector position, velocity, and force.

A backstepping-type controller for a 6-DOF active magnetic bearing system

In this paper we utilize a nonlinear model of a six degree of freedom (DOF), active magnetic bearing system to develop a nonlinear backstepping-type controller for the full-order electromechanical system. The controller requires measurement of the rotor position, rotor velocity, and stator current, and achieves global exponential rotor position tracking.

Boundary control for a general class of string models

We study the control of an undamped, nonlinear string model with actuator dynamics at the boundary. Specifically, we develop a boundary controller which asymptotically stabilizes the out-of-plane displacement. The performance of the controller is illustrated via dynamic simulation.

Boundary control of a flexible cable with actuator dynamics

We develop boundary controllers for a flexible cable with actuator dynamics at the boundary. Specifically, we develop an exact model knowledge controller which exponentially stabilizes the position of the cable and an adaptive controller which asymptotically stabilizes the position of the cable while compensating for parametric uncertainty. The performance of the controllers is illustrated via experimental results.

Repetitive Control for an Electrostatic Microbridge Actuator

Electrostatic microactuators are used extensively in MEMS sensors, RF switches, and microfluidic pumps. Due to high bandwidth operation, however, reduction of residual vibration using feedback control is diffcult to implement. This paper designs, proves stability, and simulates a feedforward repetitive controller for an electrostatic microbridge. Squeeze film damping ensures boundedness of the distributed transverse displacement. Offline processing using repetitive control algorithm updates a waveform generator’s parameters based on measured response to reduce errors between the desired and actual displacement distribution. Simulations show a 36% reduction in midspan overshoot.Copyright

A hybrid learning/adaptive partial state feedback controller for RLED robot manipulators

In this paper, we present an adaptive partial state-feedback repetitive learning control algorithm for a rigid-link electrically-driven (RLED) robot manipulator actuated by brushed DC (BDC) motors. The proposed controller is designed to compensate for repeatable mechanical uncertainty via a learning control term while an adaptive control loop is used to compensate for parametric uncertainty in the electrical dynamics. The proposed controller guarantees semi-global asymptotic link position tracking while only requiring measurements of link position and electrical winding current (e.g. measurements of link velocity are not required).