鈴木 智

Recently, in order to carry out tasks efficiently such as infrastructure inspection and goods transportation, operations using multi-rotor Unmanned Aerial Vehicles (UAVs) in formation flight are often considered. One of the main issues in motion planning among multiple UAVs is collision avoidance. Model Predictive Control (MPC) is characterized by its ability to consider collision avoidance in the framework of constrained optimization. For this reason, there have been many studies on collision avoidance using MPC, but few studies take into account the uncertainty that occurs in real environments. On the other hand, Chance constrained MPC (CCMPC) is considered to be more robust in collision avoidance due to the consideration of uncertainty. However, the structure of the collision probability constraint equation to be introduced into the evaluation function of MPC has not been sufficiently studied. In this study, the structure of equations for incorporating probability constraints into the evaluation function is examined. Moreover, by quantitatively comparing the equations with the same structure with deterministic constraints introduced into the evaluation function, the difference in collision avoidance is clarified.

In this study, we aim at realizing the adaptive control system that enables the multi-rotor helicopter to fly autonomously without the tuning by human operator. This paper presents the design of the inner loop feedback control of multi-rotor helicopter based on adaptive PID control. The controller is designed by using the theory of simple adaptive control (SAC) method. Numerical simulation and flight experiment are carried out to verify the efficiency of proposed feedback control. Copyright (C) 2019. The Authors. Published by Elsevier Ltd. All rights reserved.

In this paper, collision-free guidance control of multiple small aerial robots is designed. Collision avoidance should be considered in the operation of a fleet of aerial robots. A guidance control system using a distributed model predictive control (DMPC) is proposed to realize the collision avoidance. A constraint of the relative position vector between each robot is considered in the design for efficient avoidance. Small multi-rotor helicopter is considered as controlled object, and the guidance control system is designed by using the translational model of the helicopter. The robots exchange information about current state and optimal input sequence each other for calculating the predictive trajectory of others. Based on the calculated trajectories, each helicopter solves its local optimization problem. Here, sharing the velocity information is difficult because calculation processing capability of the small sensor and communication capability among the robots are strictly restricted. Therefore, a dynamic compensator for velocity compensation is introduced. By introducing the dynamic compensator, collision avoidance using only exchange on the position and the input sequence information is accomplished without exchanging velocity information. The effectiveness of the proposed control system is verified by numerical simulations and flight experiment.

In this study, novel robust navigation system for aerial robot in GPS and GPS- denied environments is proposed. Generally, the aerial robot uses position and velocity information from Global Positioning System (GPS) for guidance and control. However, GPS could not be used in several environments, for example, GPS has huge error near buildings and trees, indoor, and so on. In such GPS-denied environment, Laser Detection and Ranging (LIDER) sensor based navigation system have generally been used. However, LIDER sensor also has an weakness, and it could not be used in the open outdoor environment where GPS could be used. Therefore, it is desired to develop the integrated navigation system which is seamlessly applied to GPS and GPS-denied environments. In this paper, the integrated navigation system for aerial robot using GPS and LIDER is developed. The navigation system is designed based on Extended Kalman Filter, and the effectiveness of the developed system is verified by numerical simulation and experiment.

In this study, curling robot that can win in curling game with human has been developed. In previous papers, a stone delivery robot, strategy and motion simulator were developed. This paper deals with the game result of human and robot. A strategy simulator constructed by using a motion simulator that based on using the motion model. The strategy simulator evaluates the placement of stone and condition on the ice sheet, than determine the delivery parameter to the robot. Curling robot played and won one end game on irregular rules such as human team contained only one person and no time limits. This system was evaluated by the skilled coach and player after the game. Details and results of the game and evaluation result of the system were reported in this paper.

Multi-copters have the capability to control the torque in three dimensions without interference from each axis. With that feasible characteristic, multi-copters are applied for many tasks. However, they cannot control the thrust in three dimensions, only in the vertical direction. Therefore, they cannot control their position and attitude independently. Because of this drawback, applicable tasks for conventional unmanned aerial vehicles (UAVs) are limited. The proposed U AV realizes 6DOF controllability by tilting the rotors of a conventional hexacopter. The proposed UAV can undertake the tasks that cannot be done by conventional multi-copters. The authors also designed the controller for the proposed U AV and the effectiveness was verified through a simulation.

© 2015 The Society of Instrument and Control Engineers-SICE. Fleet of flying robots are expected to be applied to various practical tasks such as surveillance, inspection of infrastructures, and rescue. In this study, we aim at realizing precise formation flight of multiple flying robots. To realize precise formation flight, high tracking performance for given path is required. Therefore, tracking controller should be designed. In this paper, tracking control system based on Differential Flatness is designed for small unmanned helicopter. The numerical simulation is carried out to verify the effectiveness of designed tracking controller.

© 2015 The Society of Instrument and Control Engineers-SICE. Fleet of flying robots are expected to be applied to various practical tasks such as surveillance, inspection of infrastructures, and rescue. In this study, we aim at realizing precise formation flight of multiple flying robots. To realize precise formation flight, high tracking performance for given path is required. Therefore, tracking controller should be designed. In this paper, tracking control system based on Differential Flatness is designed for small unmanned helicopter. The numerical simulation is carried out to verify the effectiveness of designed tracking controller.

In planetary explorations, rovers are required to traverse rough terrain that often includes craters (traces of meteorite impacts) and rear cliffs (walls that become bare as a result of not being covered with soil). Hence, it is important for the rovers not to overturn or lose mobility while traversing such terrain. Planetary rovers therefore are required a high performance to traverse rough terrain like loose soil with steeps. Our proposed robot has high mobility performance, especially; it can traverse loose soil with steep slopes. The proposed mechanism can support on surface of loose soil with steep slope because of it has "piles" which are penetrated into the soil. In other word, this robot can use earth pressure to support itself weight on loose soil with steep slope. The proposed robot has two bodies and four pile's units. Two bodies are connected two ball screws units. Therefore, the mobility motion of bodies is fro-back system. Then, the piles can be penetrated into soil by mechanism with up-down system. In this study, we research the optimal piles, for instance, the optimal diameter and the optimal penetrated length. We will furthermore carry out traversing experiments using slope actually, 20°, 25°, 30°. The supporting force of a pile moreover is measured by using the proposed experiment device. From these results, we discuss traversing performance of the proposed mechanism.

Autonomous mobility robots are required a high performance to traverse rough terrain like loose soil with steeps. Our proposed robot has high mobility performance, especially; it can traverse loose soil with steep slopes. The proposed mechanism can support on surface of loose soil with steep slope because of it has "piles" which are penetrated into the soil. In this study, we research the optimal piles, for instance, the optimal diameter and the optimal penetrated length. We will furthermore carry out traversing experiments using slope actually, 20°, 25 °, 30°. From these results, we discuss traversing performance of the proposed mechanism.

In this study, the optimal mechanical design method for fixed-pitch coaxial-rotor helicopter is proposed. The fixed-pitch coaxial-rotor helicopter has several advantages compared with any single-rotor type or variable-pitch rotor type helicopters. For example, it has great simplicity of the mechanisms, well maintainability, and well energy conversion efficiency, and so on. However, fixed-pitch coaxial-rotor helicopter has a drawback in forward flight named pitch-up phenomenon. The pitch-up phenomenon causes a little cruise speed of the helicopter, and it is fatal problem in the practical operations. To overcome such a problem, optimal mechanical design of the fixed-pitch coaxial-rotor helicopter is proposed. The optimal design is based on the precise mathematical model of the helicopter and numerical optimization method. The mechanical parameters are examined to maximize the cruise speed of the helicopter. First, the dynamics of a fixed-pitch coaxial-rotor helicopter is modeled by using multi-body dynamics technique and aerodynamics theory. In the modeling, the helicopter is considered as a rigid body system consist of multiple rigid bodies, mission and frame unit, and rotors. Additionally, the aerodynamic interaction between upper and lower rotor is considered in the model. Second, mechanical parameter optimization based on derived mathematical model and Particle Swarm Optimization (PSO) method is proposed. Finally, the fundamental optimization of mechanical parameter is performed to show the validity of proposed optimal design method. In the simulation, the position of the universal joint is optimized to maximize the cruise speed of the helicopter.

In this study, we aim to achieve an autonomous locomotion of the mobile robot in the unknown environment regardless of indoor and outdoor. An information obtained from indoor and outdoor environment are completely different. In indoor case, dense information like a wall could be obtained. However, only sparse information is obtained in outdoor case. Therefore, in this study, dense information of indoor environment is convert to sparse information and same navigation algorithm is performed in the indoor and outdoor environment. For the first step of the study, the autonomous locomotion of the mobile robot in unknown indoor environment is realized. In particular, a novel landmark construction and detection method are proposed. The landmark is generated by combined image and shape features. By combining these features, some fault of each features are filled up and robust landmark detection in various environment could be achieved. In the landmark detection step, we represent the new matching method with automatic weighting for each features. The confidences are made from image and shape indicators of degree of the characteristic. The effectiveness of the proposed landmark is verified by experiment. Moreover, we introduce the novel landmark based graph SLAM. In our method, the landmark detection is performed on each node of pose graph. Then, if the robot find the landmark which is detected once, local loop closure is generated and optimization is performed. The main advantage of the method is that we can perform graph optimization before find global loop-closure. Hence, our method can minimize global error of the graph even if the robot don't come back the place visited at once. The effectiveness of the proposed graph SLAM is verified by numerical simulation and experiment.

© 2014 The Japan Society of Mechanical Engineers. In this paper, collision-free guidance control of multiple small unmanned helicopters is designed. Collision avoidance of the helicopters should be considered in the control system design for safe operation. Therefore, a guidance control system using a distributed nonlinear model predictive control (DNMPC) is proposed to realize the collision avoidance. A constraint for the relative position vector between the each helicopter is considered in the design for efficient avoidance. Small single rotor helicopter is considered as controlled object, and the guidance control system is designed for the nonlinear translational model treated a helicopter as an ellipsoid. DNMPC is designed with three constraints, an input constraint, a state constraint, and a relative position vector constraint. An input constraint and a state constraint realize collision avoidance in input within the constant limits. If the moving path of the one helicopter is significantly affected by the moving path of other helicopter, the relative position vector constraint makes the helicopters exchange their relative position each other. By using these constraints, smooth collision avoidance is realized. The helicopters exchange information about current state and optimal input sequence each other for calculating the predictive trajectory of others. Based on the calculated trajectories, each helicopter solves its local optimization problem. Here, sharing the velocity information is difficult because calculation processing capability of the small sensor and communication capability between UAVs are restricted. Therefore, a dynamic compensator for velocity compensation is introduced. By introducing the dynamic compensator, collision avoidance using only exchange on the position and the input sequence information is accomplished without exchanging velocity information. The effectiveness of the proposed control system is verified by numerical simulations.