For a two-cart system (TCS), this paper presents a new design method for a self-repairing control system (SRCS). The SRCS can automatically detect the failure of the sensor within a prescribed time, and the detection time period can be shortened by adjusting the parameter of the nonlinear detection filter. The control part of the SRCS is based on high-gain feedback which is utilized in adaptive control. However, the TCS is of the relative degree two. Hence, in this paper, the well-known backstepping strategy is introduced to make a virtual plant of the relative degree one for the purpose of high-gain feedback.

View full abstract

In this paper, a new robust active suspension control scheme is developed so that ride comfort at any specified location becomes best for four-wheel vehicle. To achieve this end, a combined ideal vehicle is de-signed so that ride comfort at a specified location becomes best easily by using only two design parameters. To achieve the good property stated above in real vehicles, a robust tracking controller is proposed.

View full abstract

The development of a clean and fuel efficient diesel engine control method is required for enhancing global environmental protection. However, in the EGR control of turbo-charged engines, the system has nonlinear characteristics, and there is mutual interference on the engine performance between the EGR valve and the VNT guide vane inputs. In this paper, we propose a cooperative control method to deal with the nonlinearity of the diesel engine, in which a method for model identification and MPC (Model Predictive Control) is introduced. As the result of using this method, which can systemize the process from model identification to the mapping of the model parameter, high environmental performance and efficiency are achieved.

View full abstract

First generation robots were mainly for application of industry. Now, next generation robots are for many applications such as security, cleaning, nursing care, living assistance, rescue, etc. We have focused on the rescue robot especially for the unknown situation. We have proposed multi-purpose module system (MMS) which consist of joint modules and function modules. The MMS can change the form such as series-connected from, quadruped form and so on. This is an advantage for unknown situation, because we can change the MMS to the appropriate form after arrived at disaster sites. We have developed several types of modules which included joint modules, sensor modules and communication modules. In this paper, we developed series-connected MMS (MMS-C) and applied the serpentine locomotion to the MMS-C. Trajectory of the MMS locomotion was evaluated by simulation and experiment. Friction force between MMS and ground was considered for simulation. The results indicated that the side slipping is properly evaluated by proposed calculation model. We believe the proposed calculation model is useful in achieving control of MMS to adapt a changing environment.

View full abstract

This paper proposes SSM (Sensor Steering Mechanism) for a lateral guided vehicle with an articulated body. Authors demonstrated the simple lateral guiding method SSM for the front wheel steer type, the reverse phase four-wheel steer type and the rear wheel steer type vehicle. SSM presents the stable lateral guiding performance for automated vehicle which follows a straight and curved path created by guideway. This paper proposes a simplified SSM to remove the following servo system for the camera rotation. The simplified SSM is applied to 1/25 scaled articulated dump truck which is developed by the previous paper. The stability of the simplified SSM is discussed. Experimental and simulation results show the stable moving and the performance of proposed method.

View full abstract

We have been developed an electric skateboard considering dynamics of a driver standing on the board. In general, the mechanism of posture control in upright standing of human is not completely understood. In this application, delay time of human body is very important because it is difficult to estimate the value and it has influence on stability of the system. In this study, we focus on the delay time in posture control. If a human standing on the board is regarding as a single pendulum system with spring, appropriate delay time depends on natural period of the system. On the other hand, the structural natural period varies according to the stance width. As a result, we assume that the delay time of posture control changes according to the stance width. The purpose of this study is to clarify the relation between stance width and delay time of human posture control on frontal plane. We implemented impulse response tests in upright standing and estimate the delay time by transfer function assuming that the system is composed of a single pendulum and control torque is generated by proportional and derivative feedback control with delayed feedback. Center of mass of human body is estimated by motion capture system and center of pressure is estimated by load mesurement devices in experiment. In this report, we denote the delay time estimated from experimental results.

View full abstract

This paper proposes a coaxial trirotor helicopter constructed with coaxial mechanism driven by one motor. There two types of trirotor unmanned aerial vehicles (UAVs) are existed. One is the single trirotor which has three motors for rotors and one servo motor for tilt angle. The other is the coaxial trirotor which has two rotors on each axis and six motors requires in total. In order to reduce the number of motor this paper discuses a coaxial mechanism which is driven by one motor. This mechanism is possible to suppress the reaction torques of each rotor. But, the counter torque of motor rotor in the direction to the rotor axis is remaining. For the control of yaw rotational angle and suppressing the reaming torque, one of the three axes has a servo motor for tilt angle rotation, as well as single trirotor type. This paper is developed a trirotor type UAV with three motors and a servo motor. Experimental results show the advantage of proposed method system.

View full abstract

In fields of sports and rehabilitation, opportunities of using motion analysis of the human body have dramatically increased. To analyze the motion dynamics, a number of subject specific parameters and measurements are required. For example the contact forces measurement and the inertial parameters of each segment of the human body are necessary to compute the joint torques. In this study, in order to perform accurate dynamic analysis we propose to identify the inertial parameters of the human body and to evaluate the influence of the model's number of degrees of freedom (DoF) on the results. We use a method to estimate the inertial parameters without torque sensor, using generalized coordinates of the base link, joint angles and external forces information. We consider a 34DoF model, a 58DoF model, as well as the case when the human is manipulating a tool (here a tennis racket). We compare the obtained in results in terms of contact force estimation.

View full abstract

Various robots have been researched and invented along with improvement of actuators. However, gigantic robot is not possible to be built with ordinary robot structure which is based on a series of rigid links connected by actuated and passively compliant joints. Square-cube law confines the limitation of size. To make up more than 10m height robot, we apply Tensegric structure which is offspring of Tensegrity for the structure of the robot. In Tensegrity, form is achieved by using a disconnected set of rigid elements connected by a continuous network of tensile elements. Tensegrity structure is so light that the king size structure can be constructed neglecting the square-cube law. This paper introduces an idea of the structure of the modular tensegric parts which configure the massive size robot and proposes the determination way of the robot-arm configuration and the wire lengths in endpoints given by operators. In the way, configuration of the arm settled on coordinate is determined along with a quadratic function. A validation of the means has resulted in effectiveness in certain endpoints.

View full abstract

This paper studies a planar passive biped walker with flat feet and knees whose motion is restricted to the sagittal plane. It consists of two legs with knees connected by a frictionless hinge at the hip and two flat feet connected to each leg by a frictionless hinge at the ankle. Torsional springs are attached to the ankles. Passive walking consists of different phases such as the double-support phase and the impact phase due to the impact between the feet and the ground. It is assumed that when the knee of the swing-leg reaches full extension, the knee joint is locked. We develop a mathematical model of bipedal locomotion by using a set of differential equations describing the dynamics of walking and discrete models describing impact events. The effects of torsional spring stiffness are investigated through numerical simulations. Numerical simulations show that the planar passive biped walker with flat feet and knees can walk stably.

View full abstract

To reduce the collision shock and injury risk to a baby in a child-car bed during a car crash, it is necessary to keep the impulsive force acting on the bed constant and below a certain allowable value. To this end, a semi-active child-car bed with joint application of regular and inverted pendulum mechanisms is proposed. This system not only reduces the impulsive force but also transfers the force to the baby's back via a spin control system, i.e., the force acts perpendicularly on the bed. The spin control system has previously been developed. In this study, an acceleration control system is developed. In the proposed system, the child-car bed is supported like a pendulum by arms, and the pendulum system is supported like an inverted pendulum by arms. And, the acceleration affecting the bed is controlled by adjusting moments of the revolution joint between the base and the arm and the revolution joint between the arms. Then, its effectiveness is confirmed via numerical simulations. The proposed system gradually increases the acceleration affecting the bed and keeps it at about the reference value of -25 G, when the vehicle decelerates at 30 G.

View full abstract

In order to improve the labor environment of dangerous agriculture work or to correspond to reduction of worker by population ageing of the farmer, it is necessary to perform technical development which eases the burden of agricultural work. The weeding work is one of the agricultural work of high load in such a background. Therefore, authors developed Brush-cutting robot which can move off-road using articulated steering mechanism for weeding work by published paper. This paper proposes a method of the self-localization in outdoor using Laser Range Finder, GPS, odometry, environment map and this robot, and show autonomous driving in grassland using lateral guid method "Sensor Steering Mechanism" which is established for the articulated vehicle that was proposed by the authors.

View full abstract