Takashi Takimoto

Dynamic state-derivative feedback control for quadrotor helicopters

We consider an attitude stabilization of a quadrotor helicopter with a sensor offset by a state-derivative feedback controller. The sensor offset produces non-zero steady-state input and output, even if the quadrotor helicopter is stabilized. In previous research, it has been investigated that steady-state blocking zeros of the stabilizing controller play an important role. In this paper, we develop a design method for a dynamic state-derivative feedback controller. Then, we show that the proposed state-derivative controller eliminates the bias in the steady-state and stabilizes the quadrotor helicopter attitude.

Development of throw type automatic photographing device

In disaster, it is important to photographs and video from the sky. Aerial photographing devices such as helium gas balloons and helicopters have ever been used for information gathering activities at that time. However, these devices have a high risk because they are strongly affected by air stream at low airspace. As the new photographing device improving the above problem, in this paper, we have developed a throw type photographing device packaged in a plastic capsule egg, and proposed an automatic photographing system. The photographing device is controlled by the control circuit with an accelerometer and takes a photograph when it reaches the top of air. The accelerometer is used to calculate the time that the device until photographing. Moreover, we take aerial photographs in practice and show the effectiveness of the proposed system.

Washout control for inverted pendulum mobile robots with sensor drifts

We consider a stabilization problem of an inverted pendulum robot with a sensor drift by using a dynamic state feedback controller. The sensor drift occurs a bias in the steady-state, even if the inverted pendulum is stabilized. In previous research, it is investigated that steady-state blocking zeros of the stabilizing controller play an important role. Such a controller is called a washout controller. In this paper, we propose a new washout controller which eliminates the bias in the steady-state. Then, we develop a design method for the proposed washout controller that can be designed by a stabilizing state feedback gain.

Development of Flying Observation System with Helium gas balloon and Tilt rotors

This paper deals with a flying observation which are consist of a helium gas balloon and a tilt rotor helicopter. The helium gas balloon can make flight for a long time. The tilt rotor helicopter is stable in the wind and increase buoyant force. The observation system with the helium gas balloon and the tilt rotor gets the best of both worlds. In general, helium gas is released from a balloon in every aerial photographing work. Moreover most aerial photographers with the balloon give up a flight in the wind of 5 m/s or greater. However proposed device does not need to release helium gas. Additionally, the flying observation device in the proposed can make a flight in the winds of 5 m/s or greater.

Stabilization of uncertain equilibrium points by dynamic state-derivative feedback control

We consider a local stabilization problem of an uncertain equilibrium point existed in a nonlinear continuous-time system by a state-derivative feedback controller. In previous researches, it is investigated that the uncertainty of the equilibrium point results in nonzero steady-state control input so that a different equilibrium point is stabilized. Then, a feedback controllers with steady-state blocking zeros eliminate the dependence on the steady-state. In this paper, we focus on the class of state-derivative feedback control, and develop a design method for a dynamic state-derivative feedback controller with steady-state blocking zeros. The proposed controller can reject the dependence on the uncertainty of equilibrium points. Moreover, we illustrate the effectiveness of the proposed control method by the numerical example which is the stabilization problem of the uncertain equilibrium point. In addition, we show that the poles of the closed-loop system with the proposed dynamic controller can be assigned at the desired locations.

Development of gliding locomotion robot by single servo motor

The gliding locomotion is defined as forward motion by the difference of friction between normal direction and tangential direction. Unlike conventional propulsion, the gliding locomotion method can move on low friction surface. Gliding locomotion robots have a simple mechanism, but it is difficult to control these robots. In previous researches, many gliding locomotion robots have been developed, and most of these robots need some actuators. In this paper, we have considered mechanism of the gliding locomotion which uses only one servo motor. Moreover, we have developed a robot with this mechanism which can move forward and turn. Then, we have shown experimental results that illustrate the effectiveness of the proposed mechanism.

Attitude control of quadrotor helicopters with sensor offsets

We consider an attitude stabilization problem of a quadrotor helicopter with a sensor offset by using a dynamic state feedback controller. The sensor offset produces non-zero steady-state input and output, even if the quadrotor helicopter is stabilized. In previous research, it has been investigated that steady-state blocking zeros of the stabilizing controller play an important role. Such a controller is called a washout controller. In this paper, we apply the washout controller to the attitude stabilization for the quadrotor helicopter with the sensor offset. Then, we show that the washout controller eliminates the bias in the steady-state and stabilizes the quadrotor helicopter attitude.

Development of an unmanned autonomous flying wing for aerial observations

The unmanned aerial vehicles (UAVs) are the aircraft without a human operator on board. Since operators can control the aircraft without some danger, they are useful as an emergency aerial observation method. In this paper, as one of these UAVs, we focus on the flying wing which is a fixed-wing aircraft. In general, the fixed-wing-type UAV can fly longer time than the helicopter-type one because the lift force is produced by rotation of propeller only. However, since the flying speed is very fast in order to produce lift force, it is difficult to take the stationary picture for the observation. Therefore, we have developed the flying wing which can fly slowly at a small field. Moreover, in order to realize the autonomous flight, we have proposed a target point follow-up control method. Then, the effectiveness of the proposed flying wing is explained by experimental results.

Development of surface vehicle with single motor by gliding locomotion

The conventional screw propeller is widely used for ships and water vehicles. However, the screw propeller has safety problems that get entangled in the fish net or the algae. In addition, the propulsion by the screw consumes a lot of energy. The goal of our research is the development of an alternative propulsion method for the unmanned surface vehicle to the screw propeller. In this paper, we focus on the gliding locomotion which is defined as the forward motion by the difference of the friction between the normal direction and the tangential direction. In particular, we have considered a mechanism of the surface vehicle propulsion with the gliding locomotion using only single servo motor. Moreover, we have developed a model vehicle with the proposed propulsion which can drive forward and gyrate. Then, we have shown experimental result and consider the performance.

Development of Aerial Photographing System with Throwing Device for Disaster Information Gathering

Recently, as a disaster information gathering tool, aerial photographing devices which gather photos and videos from the air get much attention. Especially, the aerial photographing method at low altitude below 15 meters is important to the disaster information gathering. As these devices, there are helium gas balloons, radio-controlled helicopters, and pole/crane vehicles. However, these devices have risks that trigger accidental contact and crackup by air stream at low airspace. In order to improve the safety of these devices, in this paper, we have developed a throw type photographing system which consists of an automatically photographing device packaged in a plastic capsule egg and a launching device. The attitude of the photographing device is controlled by the microcomputer with acceleration, gyro and compass sensors. These sensors also used to estimate the time when the device reaches the top of air. Moreover, we have shown the effectiveness of the proposed system by shooting aerial photographs in practice.