2012 Journal of Vibration and Control

Decoupled Robust Vibration Control of an Optical Table


Fu-Cheng Wang, Chung-Hung Yu, Jeff Tsung-Hui Tsai and San-Ho Yang



In this paper we propose the design and control of a novel two-layer optical table. An optical table normally needs to isolate two main vibration sources: the ground disturbances and the load disturbances. Because the suspension settings for suppressing these two disturbances conflict with each other, we applied disturbance response decoupling (DRD) techniques to treat them independently. First, we used passive elements to insulate the ground disturbances. Second, we employed DRD methods to design active robust controllers that would drive piezoelectric transducers to improve the load responses without influencing the ground responses. Finally, the designed controllers were implemented for experimental verification. The DRD theorem and robust controllers were confirmed to be effective at suppressing system vibrations.

2012 International Journal of Hydrogen Energy

Design and Control of a PEMFC Powered Electric Wheelchair


Fu-Cheng Wang and Yu-Shu Chiang



This paper proposes the design and control of a fuel-cell powered wheelchair. Electric wheelchairs can improve moving ability for people with walking problems. However, their traveling distances are limited by the capacity of their batteries. We designed a fuel-cell powered electric wheelchair that can be continuously operated, thereby extending the moving range. The system consisted of three subsystems: a commercial electric wheelchair, a proton exchange membrane fuel cell (PEMFC), and two secondary battery sets. The study was carried out in three parts, investigating the fuel-cell control, power management, and system integration. First, we designed multivariable robust controllers for a 500 W PEMFC system to charge the battery sets by constant voltage/current. Second, we designed a serial power management system, where the wheelchair motors were directly driven by the secondary battery sets, which in turn were charged by the PEMFC when their capacities dropped below a certain level. Lastly, we integrated the three subsystems and verified the system performance by experiments. The results confirmed the effectiveness of the PEMFC system as a way to extend the traveling distance of a motorized wheelchair.

2012 Advanced Science Letters

Development of an Interactive Electrical Acupuncture Mannequin


Fu-Cheng Wang, Hsiao-Wu Wang and Ching-Wu Huang



This paper proposes a design for an interactive electrical acupuncture mannequin, which consists of three main parts: detecting sensors, electrical circuits, and a user interface. First, we use conductive rubber and polydimethylsiloxane to fabricate position sensors for detecting the piercing of needles and to mimic human skin texture. Second, a scanning circuit is constructed to inspect these sensors. Third, we develop a user interface and a disease database to record a number of different diseases and corresponding acupuncture therapies. Finally, the system is integrated as an interactive acupuncture mannequin that allows users to practice their acupuncture skills and therapies. The experimental results demonstrate the effectiveness of the system.

2012 Vehicle System Dynamics

Stability and Performance Analysis of a Full-Train System with Inerters


Fu-Cheng Wang, Min-Ruei Hsieh and Hsueh-Ju Chen



This paper discusses the use of inerters to improve the stability and performance of a full-train system. First, we construct a 28 degree-of-freedom train model in AutoSim, and obtain a linearised model for analysis in Matlab. Then, the benefits of inerters are investigated by the critical speed, settling time and passenger comfort. In addition, we apply a new mechatronic network for further performance improvement, and synthesise the optimal electrical circuit for experimental verification. From the results, inerters are shown to be effective in improving the stability and performance of train systems.

2012 Advanced Science Letters

Design and Control of a Fuel Cell Powered Electric Lifter


Fu-Cheng Wang, Chung-Huang Yu, Jeff Tsung-Hui Tsai, Bo-Yi Lee, Po-Chen Kuo and Hsiao-Kan Ma



This paper illustrates the design and control of a fuel cell powered electric lifter. The fuel cell is an attractive alternative energy source and has been applied to various vehicle systems, such as bicycles, motorcycles, and personnel carriers. In this paper, we integrated a 2 kW proton exchange membrane fuel cell (PEMFC) module with a 3.5 kW electric lifter, and designed a parallel power management system. The study was divided into three main areas: fuel cell control, power management, and system integration. First, we applied robust control strategies to regulate the hydrogen flow rate of the PEMFC in order to provide steady electric power. The designed robust controller improved the system’s stability, performance, and efficiency. Second, we constructed a parallel power train, which consisted of the 2 kW PEMFC and a 23 Ah Li–Fe battery set. When the current load was low, the PEMFC was able to provide steady power to drive the lifter and to charge the Li–Fe battery set. Under high current load, both the PEMFC and the Li–Fe battery set provided electricity to operate the lifter. Lastly, these subsystems were integrated for experimental verification. Quantitative comparison of hydrogen consumption and system efficiency demonstrated the effectiveness of the proposed system.

2012 Applied Mathematics & Information Sciences

Development of a Modularized Seating System to Actively Manage Interface Pressure


Chung-Huang Yu, Fu-Cheng Wang, Tung-Yu Chou and Cheng-Huan Chen



Pressure ulcer is a fatal complication. Many long-duration wheelchair users face this threat, because many of them have difficulties in actively redistributing the pressure underneath. Therefore, using a good pressure management method is important. There are many passive cushions in the market. However, ready-made seat cushions and custom-made cushions, air-filled or jelly-filled, are not fully satisfactory. There are also air-filled active cushions which can change pressure distribution by alternately pumping different air bags; but the performance of these is not clear and cannot be optimized. There is a need to develop a good seating system for pressure management. We proposed an active approach for seating systems based on the concept that the interface pressure is changed for different shapes of a seat surface. Accordingly, we developed a system whose seating surface was composed by height-adjustable pillars. The system was with modular design. Each four-pillar unit was composed of the force sensors, position sensors, linear actuators, signal conditioners, driving circuits, signal processors, I2C interfaces and so on. The module can be chained and assembled together easily to form different seat dimensions. Due to torque requirements and economic considerations, each pillar would take up 3cm-by-3cm that should be improved in the future. The position resolution was 0.1mm and force sensor error was within 1 gram, which met our design requirements. Through a dead-weight test, each pillar of the system could provide 49N pushing force under the speed of 2.36 mm/s. Several verification tests were performed to access the whole system’s feasibility. In summary, this modularized system was capable of real-time interface pressure management.


2012 Proceedings of the SICE Annual Conference

Inverse Disturbance Response Decoupling Control of an Optical Table


Fu-Cheng Wang, San-Ho Yang and Sheng-Yao Wu



This paper proposes the design and control of an optical table, which needs to isolate two main vibration sources: load disturbances from the machine and ground disturbance from the environment. Because the suspension settings to suppress these two disturbances are conflicting, we applied disturbance response decoupling (DRD) techniques to independently treat these two vibration sources. In previous studies, we used passive suspension elements to isolate the ground disturbances, and applied active actuators to improve the load responses. However, the soft passive structures might result in large vibrations to load disturbances and damage the precision machines. Therefore, in this paper we propose an inverse DRD structure that uses stiff passive elements to suppress the load disturbances and applies the active actuators to improve the ground responses. The designed controllers are implemented for experimental verification. Based on the results, the proposed inverse DRD control is deemed effective.

2012 Proceedings of the SICE Annual Conference

Design and Implementation of Multivariable Robust PID Control for an Active Gait Trainer


Fu-Cheng Wang, Chung-Huang Yu and Chia-Hui Chen



This paper applies multivariable robust PID control for an active gait trainer for people with walking disability. We integrate linkage mechanism and motors to construct an active gait trainer, which can produce preferred gait traces. First, we find the transfer function matrices of the gait trainer. Second, because robust control can deal with system uncertainties and disturbances, we design standard robust controllers to regulate motor motions during operation. Third, because PID control is well accepted in industrial, we combine the merits of robust control and PID control, and design robust PID controllers for the gait trainer. Lastly, the designed controllers are implemented on cRIO and micro-chip systems for experimental verification. The results show the effectiveness of these controllers.
Domestic Conference

2012 Proceedings of 2012 CACS International Automatic Control Conference

Robust Controller Design and Integration for a Multiple-Axis Piezoelectric Nanopositioning Stage


Fu-Cheng Wang and Yan-Chen Tsai



This paper applies robust control to a three dimensional piezoelectric transducer (PZT) stage. PZT stages are usually applied for precision positioning. However, their nonlinear characteristics, such as hysteresis, might degrade system performance. Therefore, we applied robust control strategies to identify their linear models and regard the nonlinearities as system uncertainties which are treated by robust methodologies. The designed controllers are shown to achieve an accuracy of 5nm and 17 nrad.