This paper is concerned with the behavior of second-order continuous-time LTI systems with the pulse-width-modulation (PWM) input on sampling instants. The input term of the difference equation describing the state transition is a nonlinear map of the control parameter of the rectangular wave, i.e., duty ratio. It is shown that the nonlinearity can be exactly compensated by varying the center of each rectangular wave as well as its duty ratio.

抄録全体を表示

To prevent harmful emission, misfire detection is required by regulations. In conventional method, misfire detection was obstructed in high engine speed. To clarify the reason, the torsional vibration of the crankshaft was analyzed. The results of the analysis suggest that the torsional vibration increased in high engine speed and that the misfire effect was hidden in the torsional vibration. We found that the torsional vibration became the most serious when the frequency of the torsional vibration coincides with the frequency of the ignition. To cancel the tosional vibration, we changed the width of the misfire detection window to 120degree (720degree/cylinder number). By this change, misfire detection was enabled at 6000rpm. To realize the misfire detection which is robust to engine acceleration and deceleration, we discussed the constraints for the FIR filter coefficients and designed the detection filter. Misfire detection based on this filter was evaluated by engine test. The results showed that both every cycle misfire and isolated misfire could detected using same method.

抄録全体を表示

This paper proposes a control method for a helicopter connected to a station on the ground with power supply and signal cables. Although the helicopter has virtually unlimited flight time because of the power supply from the station, the cable applies an extra load to the helicopter. The static cable tension exerted on the helicopter is estimated on the assumption that the cable can be considered to be a catenary. We obtain the optimum cable length for each helicopter position, which minimizes the helicopter thrust needed to balance the cable tension and gravity force on the helicopter. The energy loss due to the cable load is minimized by reeling the cable in or out to maintain the optimum length, according to the helicopter position. Experiments illustrate validity of the analysis.

抄録全体を表示

This paper described a signal processing method for the car-mounted vital sign monitoring system to prevent the drowsy driving. Recently, drowsy driving accidents of highway express bus address a serious social problem. We had developed the pneumatic vital signs monitor and launched them onto the care facility and at-home care market. Usual vital signs monitor is not practical for the vehicle use because of the artifact noise. We developed the adaptive filter preventing the interference from the artifact noise, and improved the ECM (Electric Condenser Microphone) sensor to be de-saturated for the artifact noise. By comparison between medical pulse oximeter and the developed monitor system, our proposing vital signs monitor system proved to be useful in a warning against the drowsy driving and the physical exhaustion of the driver and the crew.

抄録全体を表示

This paper describes consideration of addition of industrial wireless system to hydrogen gas sensors. Several significant features are proposed and their efficiencies are expressed by finding combination of each unique characteristic. Proposed wireless hydrogen gas sensor system is expected for contribution to increasing safety of hydrogen station and related facilities.

抄録全体を表示

This paper presents a new genetic algorithm (GA) using the edge assembly crossover (EAX) to remedy a problem of the genetic algorithm with EAX (GA-EAX) for traveling salesman problems (TSPs). GA-EAX is one of the most powerful approximation algorithms. GA-EAX executes two search stages sequentially. The first search stage improves tours locally in the population, preserving a diversity of the population. The second search stage takes the population of the last generation of the first search stage as an initial population and improves tours globally to find better tours than the first stage does. GA-EAX has reportedly succeeded in updating the world records of 100,000-city-scale instances. However, GA-EAX fails to find optimal solutions or known best ones with a high probability on some several-thousand-city-scale instances. In order to overcome the problem of GA-EAX, we propose an improved GA-EAX that employs a new switching condition of the two search stages taking account of a rate of failing to improve tours and a multi-start strategy for the second stage. Through some numerical experiments, we confirmed that the proposed method succeeds in finding the optimal solutions or the known best ones with up to five times higher probabilities than the original GA-EAX. Furthermore, the proposed method succeeds in reducing the number of generations to find the optimal solutions or the known best ones by up to 24.7% in comparison with the original GA-EAX.

抄録全体を表示