In recent years, robots working in human living space with human-robot interactions are actively studied. To these robots, it is important to perform environmental cognition not only building environment map for autonomous motion of the robots but also estimating presences of human around the robots. In this study, by utilizing human state estimation function and SLAM based mapping technology, a concept and architecture of Human Motion Map by representing human behavior in the human living space as a hybrid map system are proposed. Beyond the conventional map which represents the existence of wall and objects, Human Motion Map represents not only the existence of humans in a particular location but also motion distributions. With recent improvements of the cloud computing technology, Human Motion Map can be accumulated as a kind of big data while measurements of robots are performed continuingly while it is moving around. In this paper, we propose a motion feature classification algorithm for clustering human motions geographically. Some experiment result of basic motion feature extraction, geographical clustering, and human motion behavior analyzing are provided for illustrating the validity of proposed algorithm.

Object manipulation problem by multiple cooperating mobile robots using the concept of object closure is discussed in the paper. It is the condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance during the transportation. We proposed the concept of dynamic object closure for achieving object caging task that robots team is able to cage a moving object after a predefined time interval. In the paper, a method planning caging path and by using random caging formation path determination algorithm (RCFP) is proposed for achieving dynamic object closure. Some planning results are presented for illustrating the validity of the proposed algorithm.

When we consider a coordination of multiple mobile robots, it is difficult to know the geometric relations among them. Errors in position and orientation of each robot detected by dead reckoning system are inevitable because of the slippage between wheels and the ground. To overcome these problems, in this article, we introduce a caster-like dynamics for controlling the multiple mobile robots in coordination. By using the caster-like dynamics, multiple mobile robots could handle a single object without using the geometric relations among them and the shape of the object. The effectiveness of the caster-like dynamics is illustrated through the video in which several types mobile robots handle a single object in coordination.

In this paper, we propose a concept on realizing impedance-based motion control of passive type robots for transporting a single object in coordination with a human operator. In this research, we developed a prototype of passive type robot referred to as passive robot porter or PRP, which consists of three omni-directional wheels with MR Brakes, and on-board computer system. We analyze the singularity of PRP braking torques, and control the brake torque of each wheel based on the brake force/moment constraint so that impedance characteristics is realized on PRP with human's pushing. This allows a PRP to track a 2D path which includes motion perpendicular to human's pushing direction without using servo motors, and multi-PRPs to work cooperatively on handling a single object with orientation control for avoiding collision with obstacles. Experimental results are shown to illustrate the validity of the proposed concept.

In this paper, we introduce a passive mobile robot called PRP to realize a transportation of an object in cooperation with a human which is developed based on a concept of passive robotics. The PRP (Passive Robot Porter) consists of three omni-directional wheels with servo brakes and a controller. It can manipulate an object by controlling an external force/moment applied by a human based on the control of the servo brakes. Therefore, if the required external force and moment for realizing the manipulation of the object are become large, the burden of the human would increase and the controllability of the robot would decrease. To overcome these problems, in this paper, we propose a system in which the PRP carries the object through a free joint. By using the free joint, the orientation of the object is changed by the intentional moment applied by the human and the robot only controls the position of the object based on the servo brake control, so that the required intentional force for transporting the object could reduce compared to the previous version of the PRP without using free joint. Additionally, in this paper, we propose a motion control algorithm for the PRP with free joint and illustrate the validity of the proposed system and its control algorithm through the experiments of the object handling.

This paper proposes a new control approach for an active (motorized) robotic walking support system based on passive behavior concept. The control approach aims to enhance the interaction between the support system and the user. The passive behavior of a support system allows the user to safely interact with the system since it removes the system's capability to move when there is no user's intention. This passive behavior is realized using imposed apparent dynamics, which uses the user's intention represented by the applied force/torque to derive the system's desired motion. The control approach is extended into a user-oriented motion control algorithm to adapt user's controlling characteristics. This is implemented by varying the point of application of the apparent dynamics. The control approach is further extended to use environment information and realize environment feedback concept. This is implemented by varying the parameters of the apparent dynamics based on environment data. Experimental results are presented to show the validity of the proposed control approach.

This paper presents an approach in assisting a sit-to-stand movement using a robotic walking support system. In general, robotic walking support system is used to provide walking stability. We will extend its function to assist a user in executing a sit-to-stand movement. The first approach would be called passive support. In this approach, the support system would be stationary as the user execute the sit-to-stand movement. The knee torque would be determined and this would be compared to a sit-to-stand movement without support. The second approach would be called active support and the knee torque would be supported. A motion control algorithm would be proposed such that the support system will move based on the supporting torque. The actual experimentation on both approaches in assisting a sit-to-stand movement will be presented. The experimental result on active support shows the validity of the proposed motion control algorithm

We have developed a wearable anti-gravity muscle support system, which assists daily activities of physically weak persons by reducing the load to lower extremities. Many activities of human beings are performed smartly by cooperative motions of different body parts to distribute loads. In this paper, we propose a dynamics-based support concept adapted to the cooperative motion in order to assist a user smartly and naturally by the wearable support system. Experimental results illustrate the validity of the proposed concept

We have proposed a dance partner robot, which has been developed as a platform for realizing the effective human-robot coordination with physical interactions. In the previous research, we have improved an estimation system for dance steps, which estimates the next dance step intended by a human. Although estimating the intended step is important for realizing the human-robot coordination, the cases that the estimation is failed and that the robot selects an incorrect step are not considered. Such cases have to be discussed carefully for realizing the effective human-robot coordination. In this paper, a method for error detections of dance step selections are proposed, which is designed using hidden Markov models. Experimental results illustrate the validity of the proposed method

In this paper, we discuss the manipulation of planar objects by multiple cooperating mobile robots using the concept of object closure. It is the condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. We proposed the concept of dynamic object closure for achieving object caging task that robots team is able to cage a moving object after a predefined time interval. A random caging formation testing algorithm (RCFT) is proposed for checking dynamic object closure condition. Some simulation results are presented for illustrating the validity of the proposed algorithm

In this paper, to construct the system, which can assist daily activities of physically weak person more smartly, we propose a new wearable antigravity muscles support system, which supports antigravity muscles based on the posture and motion of user. In this system, a dynamics-based control algorithm for the device without using biological signals is implemented to the wearable antigravity muscles support device. Experimental results show the potential of this proposed system.

We address the manipulation of planar objects by multiple cooperating mobile robots using the concept of object closure, a condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. In this paper, we develop a distributed testing algorithm of object caging by multiple cooperative robots. By implementation of a complete testing based on the sufficient and necessary condition of object closure, the proposed algorithm works efficiently even for case to cage an irregular object.

We propose a leader-follower type motion control algorithm of multiple mobile manipulators handling a single object in coordination. In this algorithm, the representative point of each robot is controlled as if it has a caster-like dynamics in 3-D space, and each robot handles a single object in coordination with other robots without using the geometric relations among the robots. The proposed control algorithm is experimentally applied to multiple mobile manipulators, and the validity of the proposed control algorithm is illustrated by the experimental results.

This paper addresses the problem of multi-robots object transportation by using the concept of Object Closure. In contrast to Form or Force Closure which is used in the research of grasping, Object Closure is a condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. Once Object Closure is achieved, the robots can cooperatively drag or flow the trapped object to the desired goal. In this paper, we address the concept CC-Closure Object and testing algorithms using properties of CC-Closure Object. Also the scaling and control problem of caging formation is addressed and two algorithms to realize two-effectors pushing on fixed caging formation control is proposed.

In this paper, we address a decentralized control method for object transportation in coordination by using a leader-follower type multiple robot system, which consist of a pushing leader, a leader robot without grasping mechanisms, and multiple follower robots. During the object transportation, a desired trajectory is given to the leader robot only, and follower robots estimate the trajectory of the leader based on force/moment from the object. In the proposed system, a variable internal force is introduced to each robot's controller in decentralized style to let the follower's estimator work on not only the pushing but also the "pulling" case that the leader needs to slow down or move back the object. Finally, a multiple robot system including three omni-directional mobile robots is presented and experiment results are shown to illustrate the concept of the proposed control algorithm.

In this paper, we propose a decentralized control algorithm of multiple mobile manipulators for handling a single object in cooperation with a human. In this algorithm, a grasping point of each mobile manipulator is controlled as if it has a caster-like dynamics referred to as virtual 3-D caster, and each mobile manipulator could handle the object based on an intentional force/moment applied by a human. In addition, the coordination among multiple mobile manipulators was realized without using the geometric relations among robots. The proposed control algorithm is experimentally applied to two mobile manipulators referred to as DR HelperII and experimental results illustrate the validity of the proposed control algorithm.

This paper addresses the problem of multi-robots object transportation by using the concept of object closure. Once object closure is achieved, the robots can cooperatively drag or flow the trapped object to the desired goal. In this paper, we address the concept CC-closure object used for efficient testing of object closure. Properties of the CC-closure object and testing algorithm are described. Finally, an example of object closure constructed from both bodies and hands of mobile-manipulators is discussed and an experiment is presented for illustrating the proposed concept.

This paper addresses the problem of multi-robots object transportation by using the concept of object closure. In contrast to form or force closure which is used in the research of grasping, object closure is a condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. Once object closure is achieved, the robots can cooperatively drag or flow the trapped object to the desired goal. In this paper, we address the concept CC-closure object, which is used for efficient testing of object closure. Testing algorithms using these properties is described. Also object closure margin is defined and the scaling and control problem of the caging formation is addressed. Finally, an example of object closure constructed from both bodies and hands of mobile-manipulators, which have different shape and size, is discussed and experiments are presented for illustrating the proposed concept.

This paper addresses the function distribution and behavior design problem for a multirobot system which incorporates a behavior-based dynamic cooperation strategy for object handling. The proposed multiple robot system is composed of a managing robot and homogeneous behavior-based robots. The cooperation strategy in this system is realized in two steps: designing the distributed robot's cooperative behavioral attributes according to the robot's abilities, and organizing these behavioral attributes so that team cooperation is realized. For indicating an incremental style of local behavior construction, an advanced design of cooperative behavior for coping with unknown disturbance is addressed. Additionally, two extended cooperation strategies designed for a path tracking task are described. These three strategies are based on the same concept on performing manipulation in coordination. Therefore, by considering the function distribution among the managing robot and worker robots, and considering behavior design of each worker robot, the proposed system is able to achieve the object handling task with different performances according to the task requirement, such as with or without path tracking and with or without contact with the environment. Experimental results demonstrate the applicability of the proposed system.

Road-following by mobile robots under varying outdoor illumination demands special care to be taken on development of an algorithm, which should be flexible to color changes in sunny or shadow parts. The ill-structured weak-paved or dirt roads such as forest or mountain roads have no significant geometrical shape and are not planar. This paper describes a selective color-based road extraction method, in which appropriate color parameters are selected by one sample color of the road. We also report on experiments with mission of a small 4-wheel mobile robot equipped with a color camera sensor through a real natural field.

We address the manipulation of planar objects by multiple cooperating mobile robots using the concept of object closure. In contrast to form or force closure, object closure is a condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. Once object closure is achieved, the robots can cooperatively drag or flow the trapped object to the desired goal. We define object closure and develop a set of decentralized algorithms that allow the robots to achieve and maintain object closure. We show how simple, first-order, potential field based controllers can be used to implement multirobot manipulation tasks.

In this paper, we propose a decentralized control algorithm of multiple mobile manipulators handling a single object in coordination. In this algorithm, the grasping point of each robot is controlled as if it has a caster-like dynamics in 3-D space, and each robot handles a single object in coordination with other robots without using the geometric relations among the robots. The proposed control algorithm is experimentally applied to three mobile manipulators, and the validity of the proposed control algorithm is illustrated by the experimental results.

This paper extends the constrain-move strategy for four robots lifting an object in a distributed manner. Ahmadabadi et al. (1996, 1998) have successfully applied constrain-move to three robots, but due to existence of redundancy in vertical forces in a team of four robots, this protocol is not applicable to such systems in its original form. In the presented cooperation strategy, the robots support the load on its bottom face and there is no lateral artificial constraint on the object. The distributed coordination protocol is designed in such a way that with minimum volume of communication and implementing their own local sensors, the robots can lift the object while its Euler angles and robot-object contact are controlled. Stability condition for the system is attained mathematically. Simulation results are given to support the applicability of the presented system.

A real-time obstacle avoidance algorithm is presented for autonomous mobile robots equipped with a CCD as its only sensing modality. The approach uses segmentation technique to segregate ground from other fixtures. It uses a simple computation for the threshold value. The processing speed of the algorithm is fast enough that it can avoid some active obstacles. The algorithm was tested in various lighting conditions in an indoor environment and is remarkably robust. Results of the different thresholding techniques are also presented in conjunction with our computation of the threshold value.

Describes a multi-robot system which incorporates a behavior-based dynamic cooperation strategy for object transportation with various requirements on task performance. This cooperation strategy is realized in two steps: designing the distributed robot's cooperative behavioral attributes according to its abilities and task dynamics, and organizing these behavioral attributes so that the team cooperation is realized. Through the behavior design, this strategy allows the dynamic cooperation control to be distributed equally to each robot. Constraint-based behavior is designed to cope with the requirements of task performance. In organizing robots' abilities, the concept of form closure is introduced as the basic strategy and additional closure rules are introduced to realize various constrained motions.

This paper describes a robots system BeRoSH which incorporates a behaviour-based dynamic cooperation strategy for multiple behaviour-based robots. This behaviour-based dynamic cooperation strategy is realized in two steps: designing the distributed robot's cooperative behavioural attributes according to its abilities, and organizing these behavioural attributes. Through the behaviour design, this strategy allows the dynamic cooperation control to be distributed equally to each robot. In organizing the robots' abilities, the concept of form closure is introduced as the basic strategy. An experimental robot system and experimental results of object transportation and assembly work are also shown.

A multiple vehicle robot system for cooperative object manipulation is described. This system consists of a host and several distributed behavior-based vehicle robot agents. A strategy on cooperatively organizing the behavior-based robots which only have limited ability in manipulation is discussed. An extended subsumption architecture, which has some layers for manipulation and cooperation, is built for each vehicle robot. A simulator and some simulation results are also shown.>