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For planetary exploration, small robots of just a few kilograms installed in the main spacecraft have a lot of advantages. Small robots can provide us with a wide range of exploration opportunities by using multi-robots, technical demonstrations, and science missions which require detailed data acquisition. There are not only mission advantages, but they can also be developed in a short period of time and at a low cost. MINERVA, MINERVA II, MASCOT are examples which are installed in the main spacecraft for surface exploration. In order to move on the surface of a “low gravity” object, like the Moon by a small robot, there are several options of locomotion, such as jumping, wheels, and legs. Wheel locomotion cannot step over obstacles where the size is bigger than the wheel radius, and the structure of leg locomotion is a very complicated piece of machinery and requires a lot of actuators. However, jumping locomotion is capable of moving a long distance by one action and the number of actuators required for jumping capability is very small. In addition, it can travel a longer distance on a planet or satellite which has a gravity lower than the Earth. For instance, it can jump 6 times longer on the Moon than on the Earth. To realize jumping locomotion for small robots in a low gravity environment, the mechanism has to meet the following functional requirements. (1) it can charge the required jumping energy, (2) it can release the energy instantly, (3) it can change the amount of the energy needed to control jumping distance, (4) it doesn't consume resources such as fuel and should be able to repeat the movement, (5) it has a ground contact part to apply power, (6) the size should be small and the weight should be small (7) it can move in a space environment (vacuum, high radiation). We studied some jumping mechanism concepts to meet these requirements. Our design of the mechanism uses springs to charge the energy and they are supported and connected to the shaft structure. A jumping pad is attached to the end of the structure and pushes the ground and robot so it can jump from the ground. For actuation, only one motor is used. In our mechanism, a one-way clutch is used to change from energy charge mode to release mode. This mode change is executed by changing the direction of motor rotation. After jumping, it can change the mode to energy charge mode again. The authors have developed a research model of the jumping rover which the jumping mechanism is mounted on. This model is developed for a lunar exploration mission. Science mission equipment mock-ups and wheels are also mounted on the model. The wheel is used to control the jumping direction. In this paper, our design of the jumping mechanism, development of a research model, and test results are presented in detail.

When a remote controlled rover traverses on planetary surfaces, it is difficult to realize the traversability of the long distance because there are measurement errors in the terrain data and the time delays in communication. A rover has a time lag until the rover reaches a measurement point. Since there might be a risk of the collision, the rover is required to get new environment data, which has more precise and less error however the new data have some differences from the old one. The wrong data also causes a severe problem, which makes the inappropriateness of operator's command path. Therefore, we proposed tele-driving method with Command Data Compensation (CDC). The CDC is a system of a path correction to adapt environment changes which improves the reliability of the command path. The efficacy of CDC system was evaluated by a lot of simulations and experiments. However, the correction performance of CDC system is reduced by a large measurement error in long-distance running, and then the correction path is bankrupt. In this paper, we consider the evaluation method for a degradation of the correction performance based on the matrix analysis, which detects the early signs of pre-path collapse.

In a teleoperated system, robots are often required to easily change among various modes of operation; further, an efficient development of large-scale teleoperated systems is desired. Thus, we propose a three-layer software architecture implemented using a database node module (DNM). All modules are connected to a DNM, with connections among modules defined as virtual connections. It is possible to change connections during operation via the virtual connection of the DNM, and the DNM can achieve high-speed communication and high-speed connection changes. We examined the evaluation index of our module design using this architecture because module interface and function design influence the architecture. Finally, we confirmed that a robot based on our architecture worked in a real environment.

Soft soil covers planetary surfaces, so the wheel of a planetary rover easily slips and gets stuck. In order to prevent increase in the slip and getting stuck, the wheel can have lugs that have a shape of a paddle to improve the wheel force. There have been some studies about the influence of the lugs. However, design method of an effective lug has not been studied well yet. Since terramechanics-based wheel models have been considered with a flat wheel surface, those models based on terramechanics are not applicable to the lugged wheel. In this research, in order to establish the design method of the effective lugs, a lugged wheel model was discussed and proposed regarding the variation of the shear characteristics. The variation of shear characteristics is indicated by a shear deformation modulus. The lugged wheel model is based on the shear deformation modulus varied by the lug design. In this paper, the simulation was performed to verify the validity of the lugged wheel model, and it was confirmed that the model could formulate the performance of the wheel traversability. Moreover, the wheel experimental device was described to understand the traversability of the lugged wheel. The evaluation method of the proposed lugged shear deformation model was also considered.

In recent years, many researchers have studied and developed lunar or planetary rovers for unmanned surface exploration. By the way, mission scope of a lander, which does not have mobility, is just a point. If we can have a rover, this mission area can be expanded to two-dimensional mission area. The object of a rover mission is scientific investigation, therefore, a rover system is not a mobile engineering system but a part of scientific equipments. A manipulator has strong possibility to be one of the scientific equipments mounted on a rover. In this paper, we introduce a micro-rover called “Micro5” which has a new suspension system: PEGASUS for high-mobility performance; we discuss a manipulator for this rover and introduce a developed micro-manipulator. It has five degrees of freedom and each joint is driven by an ultra-sonic motor which needs no electrical power to keep a posture of the manipulator. The manipulator is operated with a virtual world simulator and images sent from a hand eye camera by a joystick located on a remote site.

Considering that the robots work in real environment, it is very important to recognize its condition by itself. Therefore, we are developing a self-diagnosis system for the autonomous robots. Especially, in this paper, we develop the basic sensory system and self-diagnosis method of an autonomous mobile robot. At first, we discuss the definition and classification of system accident. We also propose actual algorithm and method to diagnosis internal status of the robot using sensory information. The developed sensory system for self-diagnosis consists of multiple sensors, which are equipped on input/output node of each component. We show some experimental result using real autonomous mobile robot and our proposed diagnosis algorithm.

In this paper, our proposed software architecture for tele-operated systems such as planetary exploration rovers is introduced firstly. The architecture modularizes each function as a software module, makes advanced extendibility and flexible task management by connecting with a database via network and managing them, and, as a result, improves efficiency in development and operation stages of systems. Those functions of the architecture is realized with DNM (Database Node Module), therefore we discuss and design it. DNMs are databases to which all the functional modules on system are connected, and they require functions, which manage the connections of modules and control data flows and execution-sequences. The management function of module connections improves the system maintenancebility by applying a virtual attachment facility. The other function performing the data flows of modules is realized by a shared memory, and it is also in charge of improvement of communication speed and visualizing communication. Its system performance with DNM was evaluated with a transmission speed and a system load by a simulation, and stability assessment was proceeded by using an actual robot. According to experimental results, DNM and its system showed us their performance designed and required in this paper, and the validities of the architecture and DNM have been indicated.

We developed a lightweight, low-power microrover for surface exploration in space. Such a rover must travel safely over long distances and periods in unfamiliar terrain. We present an exploration mission, scientific significance, requirements, and technology of a rover, proposing mobility using 4 wheels and 1 supported wheel whose suspension is simple and light and as mobile as a 6-wheeled rover.

This paper presents a new type of human interface with force feedback attached to an arm, which we named Sensor Arm. The Sensor Arm can be utilized as an interface for interactive communication with the virtual environment and as a master manipulator of a tele-operation system. The number of degrees-of-freedom (DOF) of the Sensor Arm is seven, which is the same DOF of a human arm. Angle and torque of each joint can be measured. Moreover, in this system, force feedback can be realized at each joint of the human arm. To measure human force a new type of force sensor system is proposed in the Sensor Arm system.

In this paper we present a Dynamic Force Simulator (DFS) for force feedback in human-machine systems. DFS simulates object dynamics, contact model and friction characteristics of the human hand interacting with the object, in Virtual Reality. Interaction with DFS allows calculation and feedback of appropriate forces to the force controlled actuators of the sensor glove we have developed- In the future we will use this system to analyze human dextrous manipulations called Human Skill.

In this paper, the authors present a dynamic force simulator (DFS) for force feedback in human-machine systems. They propose a virtual world model with two force flows: one is the force flow from human to an object, the other is the force flow from an object to human. To use this model, the DFS simulates object dynamics, contact models, and friction characteristics of the human hand interacting with the object in virtual reality. After the derivation of kinematic and force relations between hand and object space, they balance the two forces: one from the human and the other from the object in the contact force space in virtual world and then realize the adequate feedback forces to human operator. Interaction with the DFS allows calculation and feedback of appropriate forces to the force controlled actuators of the sensor glove they have developed. In this paper grasping of a cylinder in the virtual world is presented. During object grasping, they measure joint angles and torques using the sensor glove system. In the future, they will use this system to analyze human dextrous manipulations called human skill.

A new lunar exploration mission including a lander and rovers is under studying in Japan. The main mission for lunar robotics exploration is to demonstrate the technologies for lunar or planetary surface exploration. They will cover pin-point landing technology, reliable landing scheme with obstacle avoidance, landing mechanism on rough terrain, exploration rover and tele-science technology. Lunar geologic survey will be also performed to investigate the underground materials. The working group has been conducting the feasibility study of advanced technologies for lunar robotics exploration. In the rover mission, a robotic manipulator plays an important role as scientific observation tools for geological exploration. This paper proposes a light-weight manipulator with low-power consumption function. To investigate the effectiveness of the proposed design, a manipulator was developed. This paper describes a proposed smart manipulator system. This paper also presents the environment test results on Ultra-Sonic Motor. The performance of the developed smart manipulator is discussed.

For a planetary surface exploration, grinding and drilling equipment is one of the mo st important devices in geological observation of sampled rocks. However, the equipment can't be directly applied for works in the space. More specifically, the weight of drilling and grinding machines generally used on the Earth is so heavy, an d they need lubricant. Therefore it is difficult to use them in the space. In this paper, we analyze transient process of destroyed surface of rocks. Especially, we focus on contact points between sampled rocks and the top of a horn. Through the analysis, we can suggest that a ultra sonic based device is effective to implement drilling and grinding of rocks in the space. The analysis suggests that a ultra sonic based device is effective to realize drilling and grinding of rocks in the space.

Planetary exploration requires rovers to perform a variety of challenging tasks autonomously. In order to complete relevant scientific mission, these rovers need to overcome difficulty for rough terrain traversing by "online methods". This paper discusses an idea that utilizes a rover mobile center of mass in order to aid in traversing rough terrain. According to vehicle pitch angle and contact angles, the rover recalculates the optimal position for the center of mass to minimize the indicator defined by two factors : the wheel driving force over the wheel normal force (adhesion coefficient) and tip-over stability angle (stability coefficient). Two innovative approaches are developed in this paper. The first one is that the authors defines easily comprehensible two factors, adhesion and stability coefficients for traversability indicator and proposes a method to calculate optimal center of mass position. The second one is that in the case of four-wheels drive, the relation between the front wheel and the rear wheel adhesion coefficient is easily solved and the best case for giving the driving forces can be solved as force making the front and the rear wheel adhesion coefficient equal. The authors call this "optimal force distribution method". Finally, this paper shows some simulation results for traversing rough terrain that compute the optimal center of mass while traversing the terrain.

Friction is a very old and universal issue in all mechanical systems. Since friction is non-linear, it is an ever challenging problem. Several empirical nonlinear friction models have been proposed in the technical literature. This paper does not propose any new model but it presents a new, tensor product (TP) based representation of the existing friction models which is suitable for control design. The TP model transformation is a relatively new method for transforming certain nonlinear models into polytopic model form. The main advantage of the TP model transformation is that the most of the linear state feedback design methods including Linear Matrix Inequality (LMI) can immediately applied to the resulting polytopic models to yield controllers with guaranteed performance.

In this paper, we discuss tele-driving method for a long driving of a mobile robot in the natural field and experimental results are shown. An operator uses virtual world simulator to make command path. The virtual environment of this simulator is constructed with measurement data from a rover. We have, however, a communication delay between the control station and the remote site. So, there is the difference between old map data which operator used for path planning and new data, which a rover is tracking on. The operator's path command has less reliability to avoid obstacles and to reach the goal. Therefore, to make high reliability of operator's command, we propose command-data compensation (CDC), which compensates this difference as the distortion of the environmental map

In operation environment with communication time delay, it's difficult to compose a closed loop control structure between a master and slave system, and then, some scheme to achieve the stability is necessary. In this paper, we discuss and evaluate our proposed human machine cooperative tele-drive system consisted of global and local path-planning, for a long range traversability. Operator can command any desired path as waypoint sequences, by using 3D terrain model which was measured as DEM by on-board sensor of a rover and then transmitted to the ground and evaluated with dangerousness. For corresponding to unknown obstacle, a conventional autonomous path-planning algorithm is applied between each waypoint. In addition, a rover is up-dating environment data set, and then it causes the difference between terrain data used for commanding of an operator and for traversing of a rover. Therefore, we have to compensate waypoints by using the latest measurement data which can be assumed more reliable than previous data, for corresponding to the difference automatically. Here, the difference is assumed as the distortion between each data set, and compensated by using a distortion compensation matrix which is the mapping between the old and new terrain data sets. Simulation and experimental results and its evaluations, by using the rover test-bed, are mentioned

The approach presented is this paper is based on two ideas: (1) on the planning level an electrostatic potential field in the configuration space of the robot is used. The generalized force curves are attractive to the goal point avoiding obstacles without local minima; (2) on the control level the system follows these force curves using sliding mode control. The system is attracted to the swiching manifold using sliding mode and therewith the systkm is robust to disturbances and parameter variations. the system control variables so that sliding mode occurs in the vicinity of the force field curves and the system is attracted to them. This means that the system trajectories are identical to the force field curves. Sliding mode assures robust control performance despite unknown disturbances and parameter variations.

In this paper we present a dynamic force simulator (DFS) for force feedback in human-machine systems. DFS simulates object dynamics, contact model and friction characteristics of the human hand interacting with the object in virtual reality. Interaction with DFS allows calculation and feedback of appropriate forces to the force controlled actuators of the sensor glove we have developed. In the future we will use this system to analyze human dextrous manipulations called human skill.

Intelligent cooperative manipulation is proposed as a new paradigm for human-machine interaction and cooperation. Aiming at intelligent assistance of human operators the information and power flow between operator-system-task environment is carefully analyzed using a virtual reality to simulate the task environment. Central issue of this virtual reality is the dynamic force simulator (DFS) for feedback force calculation proposed in this paper. The DFS simulates object dynamics, contact model and friction characteristics of the human hand interacting with objects in the virtual reality. An example shows the efficiency of the proposed realization scheme of the DFS. >

Summary form only given. We present Sensor Glove II (SGII), a multi-DOF haptic interface, which has 20 degrees-of-freedom. Each joint is driven by an actuator through wire transmission. We measure joint angles by rotary encoders and torques of human fingers by strain-gauges as the stress of links. The operator can interact with the virtual environment simulator by this device. It is also used for teleoperation or telerobotics. The intention is not only that SGII should be used for telecontrol but also that the robot should learn human skills, and so perform more dextrous and intelligent manipulation. SGII acquires information about the complicated movements and forces of human fingers. It is the first step in the development of the Intelligent Assisting System (IAS).

In this paper we present a system that is able to give force feedback for the handling of virtual objects to a human operator and discuss how this system can learn low-level reflective behaviors from the human. A dynamic force simulator (DFS) that simulates object dynamics, contact model and friction characteristics of the human hand was developed to interact with the object in virtual reality. The DFS allows calculation and feedback of appropriate forces to the force controlled actuators of a glove type haptic interface. The measured data is used for task-teaching of the robot in the remote site. However usually the task can not be achieved by simple playback teaching. As each task execution is different due to various sources of small errors a low-level motion behavior to compensate for this errors is needed. In this paper, this function is assumed to be a reflective behavior and we acquire it by learning from human. Two learning schemes, neural nets and radial basis functions are experimentally evaluated.

In this paper the authors propose a one degree-of-freedom master-slave system called the HandShake device (HSD). HSD is composed of two systems: one is a master system, which is grasped by an operator; the other is a slave system, which grasps an operator's palm. Two HSDs are respectively placed in a local site and a remote site so that people can physically communicate with each other through HSDs. HSD applies the virtual model method as the algorithm of teleoperation (tele-handshake).

Communication among robots is necessary for autonomous robots to execute tasks cooperatively. Previous researches related to cooperative behavior among robots have largely depended on a predefined action or communication system.. However, it is difficult to set a fixed system., and more difficult for the agents to adapt to novel situations or tasks in a dynamic environment. Against these conventional fixed systems, new systems such as an emergence scheme have been proposed. In these systems, agents are required to understand the environment through experiences interacting with the environment, and adapt to it. We describe a method for robots to learn appropriate actions including communication to adapt to the environment without giving a fixed behavior or communication system precedency.