Takashi Yasuno

Moving control of quadruped hopping robot using adaptive CPG networks

This paper describes the moving control using the adaptive Central Pattern Generators (CPGs) including motor dynamic models for our developed quadruped hopping robot. The CPGs of each leg is interconnected with each other and by setting their coupling parameters can act as the flexible oscillators of each leg and adjust the hopping height of each leg to require stable hopping motion. The formation of the CPG networks are suitable not only to generate the continuous jumping motion but also can generate the moving motion in two-dimensional, respectively. We also propose the reference height control system which including the maximum hopping height detector and Proportional Integral (PI) controller to achieve the reference jumping height. By using the proposed method, the hopping height of each leg can be control independently in order to make the posture of robots body incline ahead and move forward. We create MATLAB/Simulink model to conduct various types of experiments and confirmed the effectiveness of our proposed CPG model including the reference height control system to generate the stable moving performance while jumping continuously.

Design and implementation of fuzzy cooperative catching controller for multiple mobile robots

In this paper, the use of cooperative knowledge for a catching problem with multiple mobile robots is considered. To achieve successful capture of an escaping target, the robots have to move toward the escaping target after the robots drive the target into the catching area formed by themselves. Then, the cooperative knowledge is represented as the fuzzy formation rules, and used to surround the escaping target. The fuzzy formation rules are tuned by genetic algorithm in advance of experiments. The same controllers with the approach rules and the tuned fuzzy formation rules are mounted on three robots. The catching motions of three robots and the target are measured. Experimental results demonstrate that the proposed cooperation control is effective to catch the escaping target.

Autonomous mobile robot based on behavior decision skill and control skill of the operator

This paper introduces a human skill base control algorithm using artificial neural networks and fuzzy reasoning for an autonomous mobile robot. Neural networks are used to select a suitable motion control pattern in actual environments. The back propagation algorithm adjusts the weights of the neural networks so that the selected motion control pattern corresponds to the action, which is obtained by the operators behavior decision skill. To realize the selected motion control pattern, the orientation angle and the speed of the mobile robot are determined by fuzzy reasoning in which fuzzy rules are also automatically tuned so as to simulate the operators control skill. We have implemented and tested the proposed control algorithm on an autonomous mobile robot and some experimental results demonstrate the effectiveness of the proposed control algorithm for the autonomous mobile robot.

Effectiveness of reference height control system for tripod hopping robot

In this paper, the generation of vertical jumping motion for tripod hopping robot through reference height control system method in order to converge the differences of reference height for each leg of tripod hopping robot is discussed. The proposed control system is designed using MATLAB/ Simulink which is consisted of maximum height detector, PI controller system in the system of Central Pattern Generator (CPG). By using the approached method, tripod hopping robot can maintain the hopping motion and control the jumping height to achieve the reference height. As the result, we evaluate the effectiveness of CPG networks to keep the stability of tripod hopping robot besides of confirm the validity of using reference height control system to generate moving capability at different reference height.

Evolutionary Acquisition for Moving Performance of Reduced D.O.F's Quadruped Robot

In this paper, an application of genetic algorithm for evolutionary generation of initial poses of a quadruped robot reduced degrees of freedom is described. Each leg of the robot has a slider-crank mechanism to reduce the degrees of freedom and is driven by an actuator. To generate the suitable initial pose, the initial angles of four legs are coded by real number as gene and tuned by genetic algorithm under the estimation functions for forward movement and right and left rotating movement. As a result of tuning, the adequate phases shift among the legs is generated. The experimental results demonstrate that the proposed scheme is effective for generation of the suitable initial poses to achieve the successful forward and rotating movements and the robot can walk smoothly for omni-directional movement with the generated initial poses

Correction method of wind speed prediction system using predicted wind speed fluctuation

This paper describes a prediction of a wind speed fluctuation by using hierarchical neural network to improve the wind speed prediction. The future wind speed fluctuation (increase or decrease) is predicted with discrete value (1 or -1). The timing of the wind speed changes after 10 minutes is predicted. Time delay is confirmed during the predicted and observed values. Therefore, the timing of wind speed change is focused. Besides, the correction system of the wind speed prediction by using the fluctuation prediction result is proposed where two types of correction methods are applied. The wind speed prediction by applying RMSE method in the existence/absence of correction is evaluated. Finally, the application limit of correction when using fluctuation prediction result and effectiveness of predicting the wind speed fluctuation also will be considered.

Performance analysis of wireless warning device for upper body level of deaf-blind person

For blind people, it is generally very hard if not impossible to notice the obstacles which exist around them except by touching the objects and by hearing the information from around them. Especially the obstruction which is existed at upper level of body. The issue becomes more severe when a blind person also has multiple sensory problems such as impaired hearing. Conventionally, they rely on white canes or guide dogs to assist them in order to reach their desired destination safely. However, the conventional method is beneficial only if the obstructions are existed at below level of body. They could not sense and hear the surrounding and cannot recognize their locations. It is very hard for them to travel independently from one destination to another without the proper navigation tools. In this paper, the performance analyses of a wireless vibration warning device in order to sense the obstructions at upper level of body for deaf-blind people is described. Four pieces of vibrator are used in order to give warning signals when obstacles are detected by ultrasonic sensors which are mounted to detect the obstacle at four directions such as front, down, left and right. From the experiment which is conducted, the configuration of the vibrators in order to warn the user when the obstacles are detected is confirmed. The location and the response of the user are acquired from the experiment which has been done. By using the developed wireless vibration warning device, the upper body level obstacles can be detected without touching the object and the effective wireless vibration warning device functions successfully.

Moving motion control system on developed tripod hopping robot

This paper discussed on evaluation and validation of method in order to generate the moving motion control system of the developed tripod hopping robot. The proposed method to control the system is designed by using MATLAB&Simulink which consist of reference height control system and the networks of Central Pattern Generator (CPG) that can controlled the hopping height of each leg independently. By using this method, one of the legs of the tripod hopping robot is set to different value than the other leg in order to make the posture of hopping robots body incline ahead towards to the direction which it should move, respectively. As the result, the effectiveness of the approached method to generate moving motion of the hopping robot using CPG networks that including the reference height control system is confirmed while maintain the stability of developed tripod hopping robot from tumbled ahead.

Multiple Vehicles Semi-Self-driving System Using GNSS Coordinate Tracking under Relative Position with Correction Algorithm

This paper describes a simple and low-cost semiself- driving system which is constructed without cameras or image processing. In addition, a position correction method is presented by using a vehicle dynamics. Conventionally, selfdriving vehicle is operated by various expensive environmental recognition sensors. It results in rise in prices of the vehicle, and also the complicated system with various sensors tends to be a high possibility of malfunction. Therefore, we propose the semi-self-driving system with a single type of global navigation satellite system (GNSS) receiver and a digital compass, which is based on a concept of a preceding vehicle controlled by a human manually and following vehicles which track to the preceding vehicle automatically. Each vehicle corrects coordinate using current velocity and heading angle from sensors. Several experimental and simulation results using our developed smallscale vehicles demonstrate the validity of the proposed system and correction method.

Two-phase buck converter for battery charger of small scale wind turbine power system

In this study, we investigate the two-phase buck converter which is used to charge the battery in small scale wind turbine power system. The proposed converter consists of two pieces of a single buck converter that each output is connected in parallel. The benefit of proposed converter offers better output power that can reach two times of a single converter. Therefore, it can increase the charging speed at the time of maximum generated by the wind turbine. The proposed converter is carefully calculated and verified by the experiment of 200 Watt wind turbine. The results show that the proposed converter power output becomes twice of the single buck converter at under 4 A output current operation. And the amplification slows down when the output current reaches 12 A.