Applied Mechanics and Materials Vols. 284-287

Abstract: A backstepping adaptive iterative learning control for robotic systems with repetitive tasks is proposed in this paper. The backstepping-like procedure is introduced to design the AILC. A fuzzy neural network is applied for compensation of the unknown certainty equivalent controller. Using a Lyapunov like analysis, we show that the adjustable parameters and internal signals remain bounded, the tracking error will asymptotically converge to zero as iteration goes to infinity.

Abstract: The paper develops gas detection modules for the intelligent building. The modules use many gas sensors to detect environment of the home and building. The gas sensors of the detection modules are classified two types. One is competitiveness gas detection module, and uses the same sensors to detect gas leakage. The other is complementation gas detection module, and uses variety sensors to classify multiple gases. The paper uses Bayesian estimation algorithm to be applied in competitiveness gas detection module and complementation gas detection module, and implement the proposed algorithm to be nice for variety gas sensor combination method. In the competitiveness gas detection module, we use two gas sensors to improve the proposed algorithm to be right. In the complementation gas detection module, we use a NH3 sensor, an air pollution sensor, an alcohol sensor, a HS sensor, a smoke sensor, a CO sensor, a LPG sensor and a nature gas sensor, and can classify variety gases using Bayesian estimation algorithm. The controller of the two gas detection modules is HOLTEK microchip. The modules can communicate with the supervised computer via wire series interface or wireless RF interface, and cautions the user by the voice module. Finally, we present some experimental results to measure know and unknown gas using the two gas detection modules on the security system of the intelligent building.

Abstract: Axial-flux motors (AFM) generally have higher torque and power densities, smaller volume and weight, larger diameter to length ratio, and compact construction for the same power level than radial-flux motors (RFM). Hence, AFM are attractive alternative to conventional RFM for applying in low torque and speed servo control systems. Additionally, magnetic Hall-effect sensors and commutation circuits are unsuitable for environment with high temperature and restricted space, so sensorless driving control method of AFM by detecting zero-crossing of back-EMF signals has been achieved. Furthermore, coreless design can reduce motor total weight, normal attractive force and torque pulsation and can increase efficiency of machines as compared with conventional design with cores. Thus, this study focuses on sensorless AFM design applying for blowers in vacuum cleaners to follow the concepts of axial-flux, edge-wire with high space-utilization factors, and stators without ferromagnetic cores. The closed-loop velocity controller designs by adopting proportional-integral-derivative (PID) and fuzzy logic control (FLC) algorithms have been demonstrated effectively for the design sensorless AFM of blowers in vacuum cleaners. As a result, the settling time of velocity closed-loop control methods can be converged within 1.0 second; i.e. the vacuum cleaners can switch and operate in various speeds with different operational environment rapidly. Therefore, the system characteristics and lifetime of the designed sensorless AFM have been enhanced and satisfied the demands of blowers to employ in vacuum cleaners.

Abstract: This paper presents vibration control responses of a multi-story structure installed with a semi-active magneto-rheological(MR) damper. As a first step, performance characteristics of three different working modes for MR fluid are compared and the mixed mode type of MR damper is chosen as an optimal candidate for the vibration control of the multi-story structure. An appropriate size of the mixed mode MR damper is devised and manufactured on the basis of the field-dependent Bingham model of the MR fluid which is commercially available. The damping force of the mixed mode MR damper is evaluated with respect to the excitation frequency at various magnetic fields. After formulating the governing equation of motion for the small scaled three-story structure associated with the MR damper, the linear quadratic regulator(LQR) controller to effectively suppress unwanted structural vibrations is designed by imposing semi-active actuating conditions. The control algorithm is then empirically implemented under earthquake conditions and the control responses of the horizontal relative displacement and acceleration are evaluated in time and frequency domains through computer simulations.

Abstract: A follow spot, known as a spot light, is a kind of stage lighting instrument which projects a beam light onto a specific, mobile, and individual object, i.e. actor. The developed system pans and tilts the follow spot by using its actuator mechanism, manual operating mechanism, tracking sensors, and control system. The system operates in four modes (manual operation, pre-defined motion saving/playing, auto tracking, and console operation). In the manual operation mode, a human operates the robotic follow spot by using a force sensor (load cell). This mode is activated in emergency situations and for pre-defined motion generation. The pre-defined motion saving/playing mode is applied for motion playing, which is generated by a human. A specific trajectory, e.g. circle, rectangle, and etc., can be saved and played for future use. The auto tracking mode makes the beam light to follow the actor. A vision system is used to detect the actor’s location. In the console operation mode, the robotic follow system communicates (through DMX512 protocol) with the light console, which controls the various lighting instruments in the theater. This paper explains the system design that fulfills the above stated 4 modes in detail. In addition, experimental results are presented in snap shot photos.

Abstract: The proposed approach is to design a tracking controller for five degree-of-freedom coplanar nanostage which can provide high precision applications. This study propose a viscoelastic creep model, it was modeled as a series connection of springs and dampers to describe the creep effect. Then, utilize a PI controller using Taguchi method to search the optimization parameters to suppress the tracking error. Finally, a cross-coupling control scheme is proposed to eliminate the contour error which is typical in dual-axes tracking control problem. The developed approaches are numerically and experimentally verified which demonstrate performance and applicability.

Abstract: The paper presents the low cost redundancy interface applied in distributed servo system of unmanned aerial vehicle(UAV).Digital bus and analog dual-redundancy control interface is implemented, it can switchs to analog interface automatically when the digital bus works abnormally, the reliability and the antijamming capability of servo system are made to be promoted. CAN bus is chosen to be the UAV digital bus after analyzing the distributed servo system structure and servo equipments work condition. The operating principle of redundancy interface is expatiated, the hardware interfaces and the software process are provided，and the communication network performance is also analyzed. Both ground test and flight test indicate that the redundancy interface works steadily, CAN bus channel can switch to analog channel fast and smoothly, it can meet the needs of UAV flight control system.

Abstract: Multi-rotor is one of the emerging Unmanned Aerial Vehicle platforms. This paper covers the design, fabrication, modeling and testing of a quad-rotor control system. To take into account the salient nonlinearities, a model with six degrees of freedom nonlinear dynamics and some linear approximation of the aerodynamic part are used when extracting a linear model and designing a attitude controller. We obtained a linear model from experimental data using system identification method and developed attitude control algorithm. The control algorithm was realized using an on a board microprocessor and verified through experiment in real environment.

Abstract: This article is dealing with a modular electro-mechanical actuator (EMA). Modular EMA consists of harmonic reducer, servo motor, electric brake, multi-turns absolute encoder, drive, network board. There are various modular EMAs in the market. Most of them are used for toys and educational device. In this research, we are more focused on an industrial high power (400W) modular EMA. All of components are designed and fabricated as hollow shaft type module for applying an industrial robotic system in the future. The robot which is linked to the modular EMA is easily able to assemble and disassemble or reconfigure it. We try to implement a modular EMA and this tries to be verified through an experiment.

Abstract: Some previous studies have demonstrated that variable valve timing can effectively enhance engine performance, as well as significantly reduce fuel consumption and emission for SI engines. Use of electromagnetic valve train (EMV) in an engine allows valve timings to be variably controlled at different operating conditions. By this way, an EMV engine is superior to an engine with conventional camshaft-based valve train in improving engine efficiency. In this paper, a novel EMV, which uses permanent and electromagnet together, has been proposed. Improvements in structure, actuating method and optimal parameters for this EMV have brought many advantages about low actuating power, easy actuation and fast response, etc. The results show that this EMV achieves 15% volume reduction and 20% holding force enhancement by special armature design. With the aids of permanent magnet and valve releasing strategies, this novel EMV only needs small EMV actuating power compared with conventional EMV.