Robust periodic disturbance compensation via multirate control

Master'sMASTER OF ENGINEERIN

Advanced Driving Assistance Systems for an Electric Vehicle

This paper describes the automation of a Neighborhood Electric Vehicle (NEV) and the embedded distributed architecture for implementing an Advanced Driving Assistance System (ADAS) with haptic, visual, and audio feedback in order to improve safety. For the automation, original electric signals were conditioned, and mechanisms for actuation and haptic feedback were installed. An embedded distributed architecture was chosen based on two low-cost boards and implemented under a Robotics Operating System (ROS) framework. The system includes features such as collision avoidance and motion planning.Muñoz Benavent, P.; Armesto Ángel, L.; Girbés Juan, V.; Solanes Galbis, JE.; Dols Ruiz, JF.; Muñoz, A.; Tornero Montserrat, J. (2012). Advanced Driving Assistance Systems for an Electric Vehicle. International Journal of Automation and Smart Technology. 2(4):329-338. doi:10.5875/ausmt.v2i4.169S3293382

Improved performance of hard disk drive servomechanism using digital multirate control

Ph.DDOCTOR OF PHILOSOPH

Suppression of chatter in high-speed milling machine using spindle speed variation method with microphone feedback PID controlller

High-speed milling process is the most common and versatile technology compared with conventional milling process for machining productivity of metal cutting industry. However, the productivity of machining is often limited by chatter at high signed in milling process. Chatter is a wavy mark on a product surface finish that occurs when self-excited vibration developed during the process, which results in low surface final part then degree measure of tool wear and less in amount the spindle lifetime. Main purpose of this study is to suppress chatter by spindle speed variation method at highspeed machinery and a better surface finish. Before chatter study proceeds, nonconventional machining applied with the high-speed machining method. This experiment investigates the effects of varying combination of depth of cut and feed rate to tool wear rate length using metallurgical microscope and surface roughness using portable surface roughness tester after end milling of aluminium and P20 steel. Then, in further experiment, PID controller was developed to give on-line feedback to the machine based on data fed by the microphone sensor. The data received from microphone sensor is analyzed in time and frequency domain. Furthermore, after machining, result also was compared with the surface roughness and surface topography of all cutting conditions. Results gathered from high-speed machining method applied on non-conventional milling shows feed rate significantly influences the surface roughness value while depth of cut does not as the surface roughness value keep increasing with the increase of feed rate and decreasing depth of cut. Whereas, tool wear rate almost remain unchanged indicates that material removal rate strongly contributes the wear rate. In further experiment, material’s surface roughness and surface topography improved until 86.7% in active experiments better than initial experiments after spindle speed variation has been implemented together with highspeed milling technique. This proves that chatter occurrence during machining can be suppressed using spindle speed variation method with microphone feedback PID controller. The researches contribute to high-speed milling usage industries with extra benefits of high productivity and can conserve time and money. Moreover, this method could enable providing high efficiency, accuracy, quality of final workpieces and eliminates semi-finishing process

First applications of sound-based control on a mobile robot equipped with two microphones

International audience— This paper validates experimentally a novel approach to robot audition, sound-based control, which consists in introducing auditory features directly as inputs of a closed-loop control scheme, that is, without any explicit localization process. The applications we present rely on the implicit bearings of the sound sources computed from the time difference of arrival (TDOA) between two microphones. By linking the motion of the robot to the aural perception of the environment, this approach has the benefit of being more robust to reverberation and noise. Therefore neither complex tracking method such as Kalman filtering nor TDOA enhancement with denoising or dereverberation methods are needed to track the correct TDOA measurements. The experiments conducted on a mobile robot instrumented with a pair of microphones show the validity of our approach. In a reverberating and noisy room, this approach is able to orient the robot to a mobile sound source in real time. A positioning task with respect to two sound sources is also performed while the robot perception is disturbed by altered and spurious TDOA measurements

Robotic contour tracking with adaptive feedforward control by fuzzy online tuning

Industrial robots have great importance in manufacturing. Typical uses of the robots are welding, painting, deburring, grinding, polishing and shape recovery. Most of these tasks such as grinding, deburring need force control to achieve high performance. These tasks involve contour following. Contour following is a challenging task because in many of applications the geometry physical of the targeted contour are unknown. In addition to that, achieving tasks as polishing, grinding and deburring requires small force and velocity tracking errors. In order to accomplish these tasks, disturbances have to be taken account. In this thesis the aim is to achieve contour tracking with using fuzzy online tuning. The fuzzy method is proposed in this thesis to adjust a feedforward force control parameter. In this technique, the varying feedforward control parameter compensates for disturbance effects. The method employs the chattering of control signal and the normal force and tangential velocity errors to adjust the control term. Simulations with the model of a direct drive planar elbow manipulator are used to last proposed technique

Sensors and Technologies in Spain: State-of-the-Art

The aim of this special issue was to provide a comprehensive view on the state-of-the-art sensor technology in Spain. Different problems cause the appearance and development of new sensor technologies and vice versa, the emergence of new sensors facilitates the solution of existing real problems. [...