There are a lot of studies of step climbing for a mobile robot. However, almost all studies do not discuss the relation between the ability of step-climbing and the angle of entering step. We proposed a differential passive suspension mechanism for a mobile robot with two independent drive wheel and evaluated the ability of step-climbing with slantwise entering angle. In this paper, we improve and evaluate the mechanism with the numerical simulator and by the experimental model. As a result of the experiment, it was confirmed that the mechanism improved the ability of step-climbing with under 30 deg entering angle.

This paper deals with 3D flight path tracking control for unmanned aerial vehicles (UAVs) under wind disturbance. A 3D kinematic model for UAV flight is represented using the Serret-Frenet frame. A guaranteed cost controller minimizing the upper bound of a given performance function is designed to carry out tracking control for given 3D flight paths. The simulation results show the utility of the proposed 3D flight path tracking control under wind disturbance.

This paper describes the mechanism of the quad-rotor flying robot that ca prevent rainwater from infiltrating into its body and rotor parts. The robot consists of three parts such as a rotor part, a body part and a leg part. The rotor and leg parts are made of CFRP, the body part is made of CFRP composite materials, and the connecting portions is made of ABS and acrylic resin. Semicircular blade covers made of CFRP are attached around the rotor part to prevent contact between propellers and objects. Also, an aluminum heat sink is attached to a battery mounting plate to cope with the heat generated by electrical elements. Through several experiments the effectiveness of the mechanism of the flying robot is confirmed.

This paper describe development of a octocopter to execute hammering test, which is one of bridge inspection method. The octocopter is developed to inspect bridges substituting for human inspectors. In the bridge inspection, the inspectors are required to conduct hammering and visual tests to find defects. To conduct the hammering test, the octocopter needs to contact object surfaces and to keep contact force. The object surfaces are floor slabs and bridge piers, therefore the octocopter needs one DoF manipulator at least to contact them. The contact force against the floor slabs is proportional to throttle rate of the octocpter, and the force against the bridge piers is proportional to its pitch angle and weight. Therefore, one DoF is enough to control the contact force. A experiment shows that the octocopter can keep contact against the object surfaces.

This paper presents stable flight control for a flying-wing unmanned aerial vehicle (UAV). A six-degree-of-freedom nonlinear model for the UAV is constructed using wind trennel experimental data. The nonlinear model is separated and linearized as longitudinal and lateral models around a trimmed equilibrium. We design two stable controllers for the longitudinal and lateral models and investigate their performance through various flight simulations. The simulation results show the applicability of the designed controllers to the real flying-wing UAV in real environments.

In recent years, Unmanned Aerial Vehicle(UAV) is used for various purpose such as disaster investigation and Aerial photography. Vertical takeoff and landing(VTOL) used in this study is a UAV which has advantages of fixed wing aircraft and rotary wing aircraft. Tail sitter is one of VTOL. Tail sitter can vertical take-off and landing like a rotary wing aircraft, and it can fly long distances at high speed like a fixed wing aircraft.
In this study, we aim to develop a tail sitter VTOL that can fly as a rotary wing machine during hovering, and as a fixed wing aircraft in horizontal flight by attaching a multi copter to flying wing aircraft.
In this time, we designed and manufactured the flying wing aircraft for attaching a multi copter, and confirmed the operation of hovering and horizontal flight of the prototype.

In this research, I aim to develop VTOL which transitions to a horizontal flight with the movable leg equipped with a propulsion device facing the back of the aircraft. In this paper, we conducted experiments on vertical take-off and landing and hovering by a testing machine using a fixed leg equipped with a propulsion device as an introduction. I investigated the influence of the distance between the ducted fan and the deflecting plate on thrust control prior to the production of the testing machine. Experiments on vertical takeoff and landing and hovering were carried out using a test machine FLFO (Fixed Legs Flying Object) manufactured based on experimental results.

Platform carts have been used in various industries to carry heavy loads. However, heavily-loaded platform carts can’t climb step. Therefore, we verified height of the step that the loaded platform cart can climb through the simulation and the experiment with the actual machine. Further, we proposed a new loaded platform cart mechanism that enables climbing step.

This report explains a constant speed movement by the passive wheel of the tip of each leg of the four-legged robot named "Road Strider”, which can perform the leg-wheel hybrid locomotion. It moves on a flat plane by wheels and on the rough terrain with legs. “Road Strider” has unique joint mechanism which uses singular point to reduce the energy consumption when the robot stands. High energy-effectiveness is suitable for the various application, especially the robots acts in the extreme situation like a rescue mission. To measure precisely the surrounding environment, it is important to move the robot at constant speed. To make the constant speed movement, constant velocity motion in wheel motion is considered and implemented to the robot.

We proposed a stair climbing robot with a simple mechanism that takes into consideration the model of "a bar stood against a wall". Because it is simple, the range of adaptation is wide and various applications can be considered.

We are studying an inverted pendulum type robotic wheelchair with the ability of climbing stairs. The structure of the wheelchair consists of a seat slider and two rotary links between the front and rear wheels on either side. As the control, we used a linear-quadratic regulator consisting of a center of gravity control mode and a rotary link control mode. This work is focused on method for preventing fall of wheelchair when it contacts with the step. We grasp the mechanism that the fall is caused by the external force received from the side of step. We proposed a method to compensate for the attitude angle moment by the command value of the rotary link torque and confirm the effect of preventing the fall.

Rotary blade of the rotorcraft turning high rotational speed, sometimes poses extremely dangerous for us. Tragic accident occurs all over the world. The purpose of this study is developing a new robot, which it can hover without such a dangerous blade. In the present paper, a new power system has been proposed and we study on new wings to use for this system. We searched form of special airfoil which met demand performances using a fluid dynamic theory for use in special environment. And we found a tendency of airfoil considered to be useful for a new system if we could solve some problems.

Small multirotor unmanned aerial vehicles (UAVs) are convenient for multiple applications because they can hover and vertically take off and land. However, their posture in landing motion is unstable because of ground effect. However, ground effect on small quadrotor UAVs has been unclear compared to that of an isolated rotor. To examine the ground effect on small quadrotor UAVs, we measured thrust of a UAV model changing height from ground. In our experiment, we confirmed that thrust of the UAV was affected by ground effect at height below three times of the rotor radius. Moreover, we verified that diagonal rotor axis length changed thrust and hover efficiency in ground effect.

This paper describes an evaluation system using two three-dimensional laser range finders (3D-LRF) for a position control of multi-copter. Our research group has been tackling developing a multi-copter to inspect concrete bridges. Operation of a multi-copter requires expertise of an operator. Therefore position control is implemented on our multi-copter. To evaluate the precision of the control, the position of the multi-copter should be measured from the external environment. Therefore this study develops the evaluation system employing 3D-LRFs. 3D-LRFs get point cloud data of the multi-copter and the center of these points is calculated as the position of it. The precision of our evaluation system is assessed by comparing measurement data of it and motion capturing system (MC). The assessment shows that the system can that the system can measure the position with average error 0.07696[m]

In order to realize bridge inspection by multi-copter, we made prototype of hammering tester for mounting multicopter. A flight test was carried out using a multi-cotter equipped with this prototype hammering device. In this research, evaluation of trial hammering test equipment is shown.

This paper deals with a new Air-Land Unmanned Aerial Vehicle (UAV) with braking mechanism. The UAV is a quadrotor helicopter with two rolling protect-flame, and can not only fly in the air but also move on the ground, wall and ceiling. The braking mechanism plays an important role in a bridge inspection, since the mechanism can improve positioning accuracy of the UAV moving on the wall and ceiling. The accuracy depends on the timing of braking in the control system. This paper proposes a new and useful design method of the control system including the timing of braking for high accuracy of positioning. The effectiveness is demonstrated by some flight experiments.

This paper proposes new small-sized two-wheeled Unmanned Aerial Vehicles (UAVs) in order to get into and visually inspect a narrow-mindedness part, for example, a bridge bearing. First, we present a design method of the multi-copter with two passive wheels to downsize the wheel of the size of 66cm to size of 25cm. Second, for high accuracy positioning of inspection, a new multi-copter with two drive wheels is proposed. The effectiveness is demonstrated by some flight experiments moving on a wall and a ceiling

This paper presents measurements of a robot hand made of shape memory gel by a depth camera. The shape memory gel can be easily deformed at high temperature. Because various shapes of the hand can be realized, the measurement of its shape is required. We propose the method to measure the plate of the shape memory gel for the robot hand by a depth camera. The data of the camera includes thousands of points and we calculate eight representative points from the thousands of points. We measure the gel plate of various shapes and make their database. Examples of the measurement and calculation are presented to show the effectiveness of our method.

The purpose of this study is to develop a tactile sensor based on an ionic polymer-metal composite (IPMC) which can realize simultaneous measurements of surface shape and texture. In this paper, we verify the possibility of simultaneous measurements through experiments. The object shape is estimated by using an observer system based on an identified model of the sensor response. The roughness of the surface texture is estimated by a frequency analysis of sensing signals.

One problem in both the design and application of Electro-rheological (ER) gels is the wiring of the electrodes that must sandwich the ER gel. The use of a patterned electrode on one side only is expected to be a suitable solution for omitting the wiring to the movable electrode using ER gel. We investigated the shear stress produced by ER gel applied to such a patterned electrode during rotational and translational motion with variation of the shear rate.

Plasticized poly vinyl chloride (PVC) gel which has a large deformation by applying a voltage and high driving stability in the atmosphere is considered as a promising material for a soft actuator. To fabricate a more flexible and high performance multilayered PVC gel actuator, in this study, we attempt to develop automation technology for fabricating thin film PVC gel used in multilayered PVC gel actuator based on digital 3D printing technology. We proposed automation system and examined to adjust amount of coating by control the condition of coating. Under the condition of 0.06 mg/shot of the amount of coated gel per shot, the average dot diameter of the point coated gel was about 0. 86 mm and the height was about 8 μm. It was expected that a gel thin film of about several μm can be automatically produced in an arbitrary shape by using the proposed system.

In this study, we developed a torque controllable device using a magnetorheological fluid with several ten nanometer sized Fe particles (Nano-MRF). We described the structure of the device and measured the static and dynamic torque characteristics with a rotational testing machine. The results shows the Nano-MRF showed better stability and response times than those of a commercial MRF.

In this study, we report on a teleoperation system for an overhead traveling crane with obstacle avoiding method by the winding. We have developed simple teleoperation systems not to cause pendulum vibrations in conveyance and overshoots at the target location. However it was only superficial operation. Therefor we implemented a winding mechanism, and experimented whether the obstacle avoidance with three-dimensional operation was possible. From in experimental results, the crane recognized an obstacle and wound up appropriately for its height. Finally, the crane reached the target location precisely, and its vibrations was converged. In conclusion, we confirmed the crane is possible to avoid obstacles with winding.

This paper proposes a small-sized two-wheeled Unmanned Aerial Vehicle(UAV) in order to get into and visually inspect a narrow part, for example, a bridge bearing. First, we present the two-wheeled multi-copter loading with a digital control device to downsize the wheel of the size of 66cm to size of 25cm. Second, for high accuracy positioning of inspection, a new design method of the optimal digital PID controller for the multicopter is proposed. The optimal controller minimizes a cost functional. The design method is reduced to the standard LQR method and is straightforward. The effectiveness is demonstrated by some flight experiments moving on a wall.

This paper proposes a new small-sized two-wheeled Unmanned Aerial Vehicle(UAV). Generally, a small-sized multi-copter has some practical problems such that the size of propeller is too small to reject against torque disturbance on the direction of the yaw, since the torque input to control is too small. In this paper, a new mechanism on thrusts using small and light propellers is added to the two-wheeled multi-copter. The additional thrusts can generate a large torque input to control the rotation of the yaw direction and to reject a large disturbance on the yaw. The design method of the new two-wheeled multi-copter with the additional thrusts is presented and the effectiveness is demonstrated by a flight experiments on a ceiling.

In the design and development of UAV (unmanned aerial vehicle), application of a variable pitch propeller which can freely change the propeller angle is expected. In this presentation, we report the frequency response of thrust change with propeller pitch angle input.

In this research we develop a robotic hand mounted on a multi-copter to perform operations with mechanical contact using a multi-copter. This hand is mounted on the upper part of a multi-copter. The lower side of a multi-copter is secured as a contact operation area performed by using another hand. We aim to prevent the fall accidents during a contact operation by fixing the body to the object to be grasped and securely perform the operation. For this purpose, we will develop a robotic hand with a locking mechanism for gripping and hanging linear objects of various thickness.

In this paper, we describe the control of an unmanned aerial vehicle (UAV) using a vision sensor with visual markers. Our research has been developing a UAV that performs autonomous flight to inspect concrete bridges. In general, UAV relies on GPS for self-position estimation. However, UAV can not acquire GPS signal in our objective environment, under bridges. Hence another sensor is necessary to estimate the position in an environment where GPS can not be acquired. Therefore our UAV use a vision sensor to estimate its own position and control it. In this study, we employs ArUco algorithm to estimate UAV’s position referring visual markers. There is still a possibility that the UAV miss the markers and can not control its position. Therefore we implemented an algorithm referring other sensor during the missing situation. An experiment shows that the UAV can control its position using our algorithm.

A quad tilt-rotor UAV has ability to fly with completely independent position and attitude control by changing the directions of the propellers. However, the control method against disturbance with this type of UAV has not been much discussed yet. This paper evaluates motion of the quad tilt-rotor UAV when the quad tilt-rotor UAV collides with an obstacle. Then, this paper proposes attitude switching flight control method considering impact disturbance. The attitude switching control method is to reset the reference attitude after the impact detected. This approach is possible only with the quad tilt-rotor UAV due to the mobility of the UAV. The numerical simulation is carried out to evaluate the efficiency of the proposed attitude switching flight control.

Synthetic fiber ropes, which are lightweight and have high tensile strength and flexibility, have attracted attention as an alternative to stainless steel wire rope. This study clarifies various physical characteristics of synthetic fiber ropes to design a tendon-driven mechanism and this paper focuses on creep of ropes. We first designed and constructed a creep testing machine for ropes. Second, we performed experiments with three types of synthetic fiber ropes and one stainless steel wire rope. As a result, in stainless steel wire rope, creep was not observed. In addition, Polyarylate(PAR) fiber rope and Poly-phenylene-Benzobisoxazole(PBO) fiber rope have much higher creep resistance than Ultra High molecular weight Polyethylene(UHPE) fiber rope.

Synthetic fiber ropes, which are lightweight and have high tensile strength and exibility, have attracted attention as an alternative to stainless steel wire rope. This study clarifies various physical characteristics of synthetic fiber ropes to design a tendon-driven mechanism. This paper investigates a viscoelasticity model for Ultra High molecular weight Polyethylene (UHPE) rope and its dynamic property applied to a long distant antagonistic tendon-driven servo system. We confirm that UHPE can be modeled by four element model, and obtained its transfer function of a tendon-driven servo system. The validity of the transfer function was confirmed by a frequency response experiment.

Synthetic fiber rope which has lightweight, high tensile strength and flexibility is receiving a lot of attention as the replacement for stainless steel wire rope. This study is clarifying various physical characteristics of synthetic fiber ropes to design tendon-driven mechanism. This paper take note of durability of repeated twist. We developed a device that repeatedly twists a wire rope and performed an experiment with one synthetic fiber ropes and one stainless steel wire rope. As a result, stainless steel wire rope didn’t get loss of tensile strength. However, repeated twists causes damage to the strands of the synthetic fiber rope, so the tensile strength of the synthetic fiber ropes is decreased.

This paper newly proposes a three-joint robotic finger mechanism on the basis of biomechanical structure of human fingers. This finger consists of MP, PIP, and DIP joints activated by two tendons and motors. This tendon driven mechanism is designed to create secure coupled motion of the joints, which can be realized by applying different insertion configuration of the tendons. We experimentally verify that the bioinspired mechanism is appropriate for adaptive grasping. Finally, this study identifies a transfer function model with respect to the tapping force from dynamic repetitive motion.

Robot driven by single actuator is one of the prominent designs that realizes the lowest weight. In order to drive multiple joints, each link has via-point through which a tendon that connects with the actuator passes, and a position of the via-point influences behavior of the robot. This study deals with the jumping robot that has three joints: hip, knee, and ankle, and appropriate via-points are searched. By grouping the via-points that provide higher jumping and successful landing, we found tendency of the via-points.

A novel 6 dof 8 cable-driven parallel robot (CDPR) is proposed. The proposed CDPR, Octave, has a pulley embedded inside moving part (MP). Octave has large rotational workspace. Octave must satisfy two conditions, wrench-closure condition. The rank of the transpose Jacobian matrix JdxT doesn't fall into deficient. At the same time, all elements of the null space vector of the transposed Jacobian matrix JdxT share the same signum. When the two conditions are satisfied, the robot is appreciated as a CDPR. In this paper, firstly, wrench-closure condition is discussed. Then, MP of Octave satisfying wrench-closure condition is proposed. Finally, Wrench closure workspace extracted.

For helicopter, the velocity parameter is important for stable real-time control, and the velocity is generally calculated by the IMU (Internal Measurement Unit) from the three-axis acceleration and three axis gyro sensors. Since the IMU unit developed and designed for multi-purpose use, high-frequency range of the acc/gyro sensors information was used for estimating the velocity and it is afraid to do overestimation of the velocity especially when the drone collision against the wall (even with light contact) and the impact due to gusts. The result shows that the IMU unit calculated velocity was divergent from the real velocity measured from the camera on the ceil even when low speed contact with a wall (50 cm/sec speed). This experimental result is generally related to all type of the four-rotor drone system, it will be necessary to consider the problem of the overestimation of the velocity to develop the drone system for inspection at infrastructure equipment such as the bridge or tunnel.

In the recently, a lot of research and development by UAV has been done. The flying robot has an advantage of being able to shoot a moving image from a viewpoint that people cannot normally see. In this paper, I propose the system for automatic monitoring of almond fields using flying robots. Specifically, I do a growth study by comparing almond leaf pixels and growth form.

This paper presents a simple model of moving robot on tree branches. We use the helicopter to move the robot with of pruning mechanism from the ground up to tree branches. So the robot can move on long branches and prune them. In this paper, the design of the mechanical equipment and simulation using Inventor Software will be presented.

This paper proposes a Passive Aeroelastic Wing. The wing mechanism is constructed mainly from flexible materials. Thus, the range of fluid resistance becomes different between high-speed flows and low-speed flows. Under fast-flow conditions, the flexible wing mechanism is compressed, and the range of the shape control becomes low. Then, the mechanism can control the posture of the robot under various flow speeds. This reports explain the construction of the proposed mechanisms by using closed loop dynamics based on the task space P-SD servo controller. The repeatability of the position control based on the proposed system were explained in the results.

This paper considers a communication range extending method using a mobile robot as wireless communication relay node for a robot teleoperation. In the case of long distance wireless communication, and wireless communication in a building and underground environment, it is necessary to extend the communication range by wireless communication relay in order to maintain communication with the teleoperated robot. The proposed method evaluates the communication quality required for remote operation, and moves the robot so that extend the communication range while maintaining comfortable operability. We confirmed that the proposed method operates as a system of “Robot Wireless Sensor Networks” in outdoor environment, and maintains its communication quality.

Authors have been developing an information gathering system using a mobile robot and Leaky Coaxial Cable in underground space at post-disaster. Leaky Coaxial Cable radiates a radio wave along the cable for constructing networks, then it able to provide wireless communication infrastructure in post-disaster environment. This paper describes a study of a mobile robot tele-operation by utilizing radiating mode of Leaky Coaxial Cable in post-disaster underground space. Network constructability of between the Leaky Coaxial Cable and the mobile robot was evaluated by measuring throughput and packet jitter as communication quality. Then availability of our proposed method was confirmed by experimental results.

For high speed pick-and-place work, we develop a 3 D.O.F parallel paired cable robot motivated by Dleta type parallel link robot. The robot consists four paired parallel wires enabling always keeping horizontal motion which is suitable for pick-up-place task. The paper proposes a mechanism using constant force spring to reduce the motor torque of the robot and high stiffness. The paper also shows advantages of using the constant force spring by position control experiments.

Wire-parallel mechanisms are categorized as two groups: fully constrained mechanisms and under-constrained mechanism. In this study, focusing on the under-constrained mechanism, a cable-suspended robot system have been developed. In such a mechanism, slacks of cables affects its design or control. In this paper, to improve them, slacks of cables are estimated by a model including the gravity and external forces as virtual cables. Experimental results valid the proposed method.

A wire suspension system with four wires is developed and a control method for the positioning of the suspended base is proposed. This system can be used for transporting heavy object, inspection of bridges by attaching a camera on the base, and so on. Since the suspended base cannot be completely restrained with four wires, the base swings against external forces or inertia forces caused by the base motions. Therefore, in this research, we propose a method to suppress the swing motions of the base by using the gyro mounted on the base. The base swing motion is eliminated by the gyro effect which is feedback controlled through an IMU sensor embedded in the base.

This paper discusses on the control system and stability of the marionette style elastic tendon driven robot arm. The idea of this robot arm is a light weighted and easily customizable structure by using low-cost materials for the links and tendons. Due to the lower rigidity of the positioning action through tendons, positioning error when carrying an unknown load is an important issue. In this paper, we show an iterative compensation method of the gravity force, based on the static relation of forces. A criterion of the error reduction, considering the nonlinearity of the tendon elasticity. Experimental results using a prototype robot arm are shown to demonstrate the basic behavior, and confirm the proposed gravity compensation method.

Non-circular pulleys and a wire can be used to constrain the motion between two rotational joints in order to generate a given coordinated motion of the joints. In this paper, the methodology to derive the shapes of non-circular pulleys for a given coordinated motion of the joints is introduced. Furthermore, the shapes of non-circular pulleys to move the robotic leg with four joints using the wire constraints are derived by this methodology for both of the stance and swing phase. The designed robotic leg can be used to develop a new passive dynamic walker.

3D printers are becoming popular and using in many scenes. They enable to make products simply and rapidly according to the design models. However, they can make only a single bulk parts at a time in general. If we can make a whole robot structure at once by 3d printer, it became possible to manufacture a desired robot on the spot in a minute. In this report, we propose a method for making a robot structure including joints at one time by a Fused Deposition Modeling (FDM) type 3D printer. It is unnecessary to assemble after printing. Further, we produced a wire-driven quadruped walking robot as an example of the proposed method.

We have been discussing a communication quality of tele-operation in between mobile robots and operator. This paper describes a method for measuring communication quality for wireless tele-operations. To prevent disconnection of wireless communication between mobile robots and operator, the operator has to monitor communication qualities. In this study, we propose the communication quality measurement method by the using command packet of mobile robot tele-operation. This propose method is not necessary to use measurement packet. The communication quality measurement system using the proposed method was implemented, then evaluation experiment was conducted. Then the availability of proposed method was confirmed by experimental results.

Latency is one of the most important factors to the overall performance of cloud robotics. In this paper, we propose a latency-aware computation-offloading algorithm for cloud robotics. We first propose a novel framework of networked cloud robotics. Then we formulate the latency-aware computation-offloading problem, and develop a MILP-based algorithm based on DFG model to obtain the feasible solution.

In this research, we study the teaching method of manipulation of medical equipment introducing human motion measurement technology and robot / ICT technology. Specifically, we quantify the work skill based on the exercise information of the operator and embody the remote work support system based on the information transmission. In this report, as a first step of the research, basic experiments on quantification of operation proficiency using 9 axis information of 3-axis acceleration, angular velocity, and geomagnetism of the worker's wrist for the operation of the ventilator are described. In addition, we report on the results of examining the effectiveness of a work support system from a remote place based on the video / audio communication function.