Seiji Sugiyama

Path planning of a mobile robot for avoiding moving obstacles with improved velocity control by using the hydrodynamic potential

This paper describes the theory and the simulation of an improved velocity potential approach for path planning by which a mobile robot avoids standing and/or moving obstacles by using the hydrodynamic potential. This potential function for path planning is feasible for guiding a mobile robot to avoid an arbitrarily moving obstacle and to reach the goal in real time without finding the local maximum or minimum points in all cases. In this theory, there are two problems. One is that a mobile robot accelerates rapidly when it avoids a moving obstacle. The other is that a mobile robot has a discontinuous velocity when it is passing a moving obstacle. An ellipse field, which is obtained by using the conformal transformation, and a correction function, which generates the continuous velocity field, are installed in the previous potential function to cope with the difficulty. As a result, a mobile robot can gradually avoid a moving obstacle from further away, and can be safely guided without rapid acceleration.

Design and fabrication of convective inertial sensor consisting of 3DOF gyroscope and 2DOF accelerometer

This paper reports the design, simulation and fabrication of a MEMS fluidic inertial sensor, which integrates three-axis gyroscope and dual-axis accelerometer so that the device can independently detect three components of angular rate and two components of linear acceleration. The gyroscope utilizes jet flow directly created from an integrated micro pump. This simplifies packaging process while maintaining good characteristics of the device. The device was fabricated by standard bulk MEMS technology. Fundamental experiments have been done, the performance of the micro jet-pump was evaluated and the sensitivity of accelerometer was characterized.

Shuffle turn and translation of humanoid robots

This paper proposes a novel shuffle-translating method that combines shuffle turns repeatedly for a humanoid robot. Conventionally, the walking motion of a humanoid robot is performed through a repeated foot stepping motion. However, this motion is inefficient and has low stability. Previously, we have studied the shuffle-turning method for a humanoid robot, which can perform a stepless and stable turning. In this paper, we present a precise shuffle turn with feedback control and a new shuffle translation method by repeating shuffle turns. Experiments using a humanoid robot were conducted and the results revealed that the proposed method was effective for shuffle translation.

Collision avoidance control with steering using velocity potential field

It is expected that a collision avoidance system based on steering control could help avoid collisions even in cases where a collision cannot be avoided by braking only. For realizing steering-based collision avoidance, accurate environmental recognition and rapid motion planning in a highly dynamic environment are needed. The velocity potential field control method, which was proposed for mobile robot motion planning, has the advantages of a very low computation cost, even in dynamic environments with moving obstacles without any deadlock. In addition, the method generates the desired velocity vector to be followed but vehicle trajectory. With this feature, avoidance velocity vector is generated in realtime even in the case that the obstacles are moving and their movements cannot be anticipated. Thus, the present study proposes a collision avoidance method with steering control by generating a trajectory for obstacle avoidance using local environmental recognition based on application of the velocity potential field approach. In addition, a parameter determination method for the velocity potential function is derived. A preview steering control method for following the derived velocity vector is proposed. The simulation results obtained using vehicle dynamics software demonstrate that the proposed method can generate appropriate obstacle avoidance trajectories, even for moving obstacles, and the derived velocity vector can be tracked by an automobile.

Measurement of grasp position by human hands and grasp criterion for two soft-fingered robot hands

In this study, grasp positions of human hands are measured for planar objects for development of a reasonable grasp criterion for a two-soft-fingered robotic hand. We first propose a grasp criterion that yields the best grasping position for a robot hand with two soft fingers. To examine the properties of this criterion with respect to some weighting coefficients included in the criterion, a grasping experiment is performed by humans for planar objects with various sizes and shapes. Results show that many observed grasping positions used by humans correspond to a set of weighting coefficients that equally weigh all the factors in the criterion. A grasping experiment using a robot has also been conducted using a set of coefficients corresponding to the equal weight; the effectiveness of the criterion was confirmed.

An event oriented data management method for displaying genealogy: Widespread Hands to InTErconnect BASic Elements (WHIteBasE)

In this paper, we propose a new data management method for handling relations on genealogy display software easily. It is named “Widespread Hands to InTErconnect BASic Elements (WHIteBasE)”. The WHIteBasE is a hidden node for integrating the relations due to an event including a married couple and their children. That is, individuals data does not refer to others directly, and only refers to WHIteBasEs. As a result, the number of references is less than the existing data structure. Therefore, the volume of database is smaller, the complex multiple marriages can be set easily, and the positions of the segment intersections can also be searched easily. Then, display traditional handwriting genealogy can be achieved on computers. Our new prototype software and the effectiveness of our method are shown.

A sliding walk method for humanoid robots using ZMP feedback control

In this paper, we propose two methods for a highly stable sliding walk for humanoid robots working in narrow areas under constrained postures. The first method uses a new displacement of the center of gravity with Zero Moment Point (ZMP) feedback control. ZMP is a force distribution on the soles of the feet. This method is faster and more stable than previous techniques. The second method utilizes sliding forward movements using the inverse kinematics of the leg mechanism, which are calculated from the positions variation of the sole. The sliding walk is experimentally demonstrated using the humanoid robot HOAP-2, and an evaluation of the lateral variations in ZMP and the lateral acceleration variations are shown.

A basic concept of displaying electronic text with seamless pages -Magnifying And Simplifying System for text EXTension (MaSSTExt)-

In this paper, we propose a new system for enhanced viewing of electronic text. It is named “Magnifying And Simplifying System for Text EXTension (MaSSTExt)”. This system for displaying text has the operational feeling like a map system displayed on a web browser. No link buttons are used for changing the other pages in this system because it is made by using Ajax. Then, it allows us to display huge text files in only one window or seamlessly display/not-display from index to body or annotation data. As using this system, footnotes, references, tables and figures on the text can be located at optimal positions. Comparing simultaneously two different texts is easy to read. Grasping a text with both a birds-eye view in its totality and a detailed view can be easy. Simulation software “MaSSTExt” of our prototype system is introduced and the effectiveness of our research is shown.

Study on geometry of valveless-micropump

A gas-jet micro pump with novel cross-junction channel has been designed and fabricated using a Si micromachining process. The valveless micro pump is composed of a piezoelectric lead zirconate titanate (PZT) diaphragm actuator and fluidic network. The design of the valveless pump focuses on a cross-junction formed by the neck of the pump chamber and one outlet and two opposite inlet channels. The structure of cross-junction allows differences in fluidic resistance and fluidic momentum inside the channels during each PZT diaphragm vibration cycle, which leads to the gas flow being rectified without valves. The flow channels were easily fabricated by using silicon etching process. To investigate the effects of the structure of the cross-junction on the gas flow rate, two types of pump with different cross-junction were studied. The design and simulation were done using ANSYS-Fluent software. The simulations and experimental data revealed that the step-nozzle structure is much more advantageous than the planar structure. A flow rate of 5.2 ml/min was obtained for the pump with step structure when the pump was driven at its resonant frequency of 7.9 kHz by a sinusoidal voltage of 50Vp-p.

Approach to haptic guidance control in steering operation based on cooperative states between driver and control system

Haptic guidance provides good affinity between the driver and the assist control system for steering assist control automobiles. It is expected that haptic shared control can achieve smooth transferring of automation authority between human and automated system because it involves continuous physical interaction. Many research studies have derived smooth transferring control authority between human and machine based on such environmental factors as position in a lane. However, it is difficult to change control authority smoothly when the drivers intent changes, due to difficulty of detecting such change. Thus, the present study proposes a method to estimate the cooperative relationship between human and machine in the haptic guidance control of a steering assist system. In addition, a gain-tuning control method based on detection of cooperative status is proposed. The proposed control method is applied to a lane-keeping assist control that enables the driver to change lanes smoothly. Finally, its effectiveness is demonstrated by experiment results using a driving simulator.