RESEARCH

Last Update 2009.6.4   

Publications List

Research Topics

• Non-linear Digital Filter, ESDS
• Integration-type Ultrasonic Wave Sensor
• Robot Navigation
• Digital Acceleration Control
• Image Processing

Research Field

• Robotics
• Control
• Nonlinear signal processing

Affiliation Society

• The Japan Society of Mechanical Engineers
• The Robotics Society of Japan
• IEEE

Research Topics

• Non-linear Digital Filter, ESDS

Key Words: impulse noise, nonlinear filter, minimum time system, differential estimator, sliding mode system.



• Purpose of the research is to smooth and differentiate the sensor inputs with impulse noise.
• We smooth the distance value by assuming the trend of the sensor inputs.
• By using the sliding mode system, our estimator neglects the excessive inputs and follow a input signal.


• Integration-type Ultrasonic Wave Sensor

Key Words: ultrasonic wave sensor, autonomous mobile robot, speed control, obstacle avoidance.



• For autonomous mobile robot, ultrasonic Time-of-flight (TOF) ranging systems are widely used to measure distance. However, it tend to neglect minute reflected waves below the threshold level.
• We have proposed a technique to utilize the minute reflected waves by integrating the reflected waves. We named it integration-type ultrasonic wave sensor.
• We propose speed control and obstacle avoidance of a sonar-based mobile robot by using integration-type ultrasonic wave sensor.


• Robot Navigation

Key Words: navigation, local landmark, topological map, autonomous mobile robot, behavior-based robot, potential function method, graph map.



• We discuss decision making for a behavior-based robot with modules which determining robot action.
• We use Potential Function, in which maximum votes are collected from modules. Using event-driven state transition, the robot decides its action with appropriate sets of modules changed based on situation.
• We apply this to navigation tasks in a corridor and show simulation results. When we give a map and path designation to the robot, we use a handwriting map interface.


• Digital Acceleration Control

Key Words: digital acceleration control, differential estimator, filter, sensor, robot manipulator.



• Digital acceleration control has been proposed in order to control non-linear mechanical systems such as robot manipulators.
• It requires position, velocity, and acceleration of controlled object in order to construct a controller.
• Not all mechanical systems can obtain the information of velocity or acceleration of controlled object.
• So, we use position sensor and differentiate it by using filtering technique. As a filter, we use nonlinear digital filter, ESDS that is based on sliding mode technique.
• It estimates smoothed and differential value of noisy input signal, but more accurate estimation is required to implement the controller. Therefore, we propose the Difference value tracking ESDS (D-ESDS) that is superior to estimate the differential value.


• Image Processing

Key Words: image processing, impulse noise, nonlinear filter, median filter, image restoration.



• The purpose of this research is noise removal, particularly removal of impulse noise, from corrupted images.
• Our approach utilizes the trend of images instead of order statistics, and it is constructed on the basis of a nonlinear digital filter termed ESDS.
• The proposed approach can respond to abrupt input signal using the differential information calculated by ESDS.

Takanori Emaru ：

(c) Laboratory of Robotics and Dynamics, Hokkaido University