In our current research, we have developed a novel standing assistance system for an elderly person. Our developing assistance system is designed compactly for family use. Our system is based on a robotic walker with novel manipulator mechanisms on its body with four parallel linkages. In this paper, we propose the assistance control scheme which can use a remaining physical strength of a patient. In general, a previous assistive device does not require the patient to use own physical strength and it causes the decreasing the physical strength of elderly people. Our key ideas are two topics. One is the real-time load estimation scheme using a human model with measuring information by our assistance system. Using this scheme, our system can change the assistance force based on the estimated results. The other is novel control scheme which consists of position and damping control. Our proposed scheme can change two control modes frequently and using this function, our assistance device can reduce a part of the load which the patient wants to reduce. This means the patient can choose two functions with our standing assistance device; (1) reducing the load for easy to stand up by own physical strength or (2) using the physical strength maximally during standing motion for a rehabilitation purpose.

In our current research, we are developing a robotic walker system with standing, walking and seating assistance function. Our developing system is based on a walker which is popular assistance device for aged person in normal daily life and realizes the standing and seating motion using the support pad which is actuated by the novel assistance manipulator mechanism with four parallel linkages. In this paper, we develop the control scheme which realizes the natural seating motion with fewer loads to the patient. For developing control scheme, we investigate the seating motion of aged people who requires to power support and typical seating motion by healthy young people. Comparing with two motions, we set the reference of seating motion with our system and we discuss the required assistance condition during seating motion. Our key ideas are two topics. One topic is analysis of condition which realizes the seating motion as young healthy people. The other topic is combination of force and position control. According to the patient's posture during seating motion, our control system select more appropriate control method from them. Using proposed control, our system reduces the patient's load and maintains his posture stably when it is necessary.

It is generally accepted that locomotion in animals is based on a trade-off between energy consumption and stability. However, this trade-off is the result of the interaction between complex mechanical and control systems. To gain insight into that issue, a step-by-step approach is needed. In this study, as a first step to investigate three dimensional quadrupedal walking, we aim at establishing a control system as “minimal” as possible, able to realize stable dynamic walk. Using a simple mechanical structure, we realized dynamic walk with a distributed control system, made of four independent leg controllers whose swing and stance phases durations are modulated based on leg loading information. Phase modulations contribute to stabilize the posture in the frontal plane via automatic duty ratios adjustments that tend to compensate perturbations of the body rolling motion. By applying lateral perturbations, we found that the control system withstands well perturbations increasing the rolling motion amplitude, but is sensible to perturbations that suddenly decrease it, as the foreleg on the more loaded side is prevented to swing. Hence, we implemented an ascending coordination mechanism where the transition to swing in a hind leg promotes the same event in the foreleg. The duration of the subsequent foreleg swing phase is reduced to prevent excessive increase of the rolling motion amplitude. The resultant control system, although extremely simple, was able to realize dynamic walk resistant to small disturbances (lateral perturbations and terrain irregularities).

This paper proposes a robotic walker system with standing, walking and seating assistance function. Our system focuses on domestic use for aged person who needs nursing in their daily life. Our key ideas are two topics. The first topic is combination of standing assistance function and walking assistance function. In previous works, many assistance devices are specialized in only ¿standing-up operation¿ or ¿walking operation¿. However, in their daily life, elderly people need standing, walking and seating assistance continuously by the same device. Therefore, our developing assistance system can support both operations by a small sized mechanism which is easy to use in the home. The second topic is a seating position adjustment assistance. From questionnaires of nursing specialists, a seating position adjustment requires the elderly people to walk backward and it is difficult operation for them. Furthermore, in many cases, a failure of this operation causes a fracture which has high risk to fall into bedridden life. Thus, our developing system can assist the aged users to adjust the seating position safety. The performance of our proposed system is verified by experiments using our prototype.

This paper proposes a robotic walker system with standing and walking assistance function. Our system focuses on domestic use for aged person who needs nursing in their daily life. Our key ideas are two topics. The first topic is combination of standing assistance function and walking assistance function. In previous works, many assistance devices are specialized in only “standing-up operation” or “walking operation”. However, in their daily life, elderly person needs standing, walking and seating assistance continuously by a same device. Our developing assistance system can support both operations by a small sized mechanism with low cost for domestic use. The second topic is steady standing assistance operation using an assistance manipulator and an active walker. In order to use the remaining physical strength of the patient, it is required to maintain the patient’s body posture which enables him to use own strength easily. According to the patient’s posture during standing up, our proposed system selects more appropriate device and controller, and realizes the standing assistance with steady posture of the patient based on the nursing specialists. The performance of our proposed system is verified by experiments using our prototype.

This paper proposes a robotic walker system with standing and walking assistance device. Our system focuses on domestic use for aged person who needs nursing in their daily life. Our key ideas are two topics. The first topic is combination of standing assistance function and walking assistance function. In previous works, many assistance devices are specialized in only “standing-up operation” or “walking operation”. However, in their daily life, elderly person requires standing, walking and seating assistance by a same device continuously. Our developing assistance system can support both operations by a small sized mechanism with low cost for domestic use. The second topic is standing assistance operation using assistance manipulator and active walker function. In order to maintain the stability of the patients during this motion, it is required to maintain the body balance of the patient into the range of his foot. According to the patient’s posture during standing up, our control system selects more appropriate controller for realizing his stability. The performance of our proposed control scheme is experimented by computer simulations and experiments using our prototype.

In this paper, a RTM-based network distributed monitoring system for human assistance robot system was developed to improve the interaction among the users and local service robotic system. Home integration robot system and network monitoring system using QuickCam Orbit cameras were developed and demonstrated from June 9 to June 19 at the 2005 World Exposition, Aichi, Japan. Improvements of network distributed monitoring system using IEEE1394 cameras with high performance and high resolution have been done in order to extend the application of system. Robot technology middleware (RTM) was used in the developed system. By using RTM, we can develop cameras functional elements as "RT software components" that can be implemented by different programming languages, run in different operating system, or connected in different networks to inter-operate. It is also easy to create comprehensive robot system application by re-using existing modules thus facilitating network-distributed software sharing and improving the cost of writing and maintaining software.

In this paper we present the system design and analysis of a quadruped robot, Rush, that we have constructed to study autonomous and efficient running on flat and rough terrain. The Rush robot is a compact, kneed, four legged machine with only one actuator per compliant leg. We have proposed a novel control strategy for the quadruped robot in consideration of several engineering limitations on sensory feedback. Several simulation studies have already been performed to confirm the validity of the control strategy in our previous reports. Here, the results obtained from experiments with Rush are found to agree with the simulation results. The work reported in this paper may help improve our understanding of energy efficient running locomotion and the simple control required to autonomously stabilize it on flat or rough terrain.

This paper proposes a walker system with power assistance device for standing up motion. Our system focuses on family use for aged person who needs nursing in their daily life. Our key ideas are two topics. The first topic is new assistance manipulator mechanism with four parallel linkages. Our proposed manipulator mechanism requires only smaller actuators and realizes rigid structure with lighter linkages comparing with general manipulator. Thus, we can design our assistance system compactly with low-cost using our mechanism. The second topic is the combination of force and position control. According to the patient's posture during standing up, our control system selects more appropriate control method from them. We use the reference of standing-up motion which is based on the typical standing up motion by nursing specialist for realizing the natural assistance. The performance of our proposed assistance system is verified by computer simulations and experiments using our prototype.

The intelligent home service robotic system has been developed in order to assist the aged or the disabled people in the population-aging society. The developed robotic system was demonstrated from June 9 to June 19 at the 2005 World Exposition, Aichi, Japan. The purpose of our research is developing robotic system to provide daily services such as bringing some objects to the elderly or disabled wheelchair users. Network distributed monitoring system was also developed in order to monitor the state of robotic system working and the state of the aged or disabled. The developed system uses robot technology middleware (RTM), which was developed by AIST (Agency of Industrial Science and Technology, Japan) to promote application of robot technology (RT) in various fields. RTM is based on CORBA, so has high scaling and inter-operating ability and facilitates network distributed software and sharing. Using RT middleware, we can develop robotic functional elements as "RT software component", which makes application and system integration easier. This paper introduces the architecture of the developed demonstration robotic system and the results of a demonstration conducted at the exhibition

Delivery is an essential task for a mobile robot. Automatically guided vehicles play a crucial role in many factories by performing delivery tasks. The next step involves having mobile robots work in populated environments, such as offices, hospitals, and health care facilities. This paper proposes a service robot that can deliver parcels, letters or documents in such an environment. The design policy, architecture, methodology and implementation of this system are presented.

We have induced a quadruped robot to walk with medium walking speed on irregular terrain based on biological concepts. The PD-controller at joints constructs the virtual spring-damper system as the visco-elasticity model of a muscle. The neural system model consists of a CPG (central pattern generator) and reflexes. A CPG receives sensory input and changes the period of its own active phase. The desired angle and P-gain of each joint in the virtual spring-damper system is switched based on the phase signal of the CPG. CPGs, the motion of the virtual spring-damper system of each leg and the rolling motion of the body are mutually entrained through the rolling motion feedback to CPGs, and can generate adaptive walking. We report our experimental results of dynamic walking on terrains of medium degrees of irregularity in order to verify the effectiveness of the designed neuro-mechanical system.

This paper proposes a novel method to integrate Internet distributed robotic systems using Common Object Request Broker Architecture for implementing telecare robotic system to aid the aged or disabled. The proposed method makes system have low cost and wide availability, high scaling and inter-operating ability to allow the clients and server objects, written in different languages, run in different operating system, and connected in different network to inter-operate. It also makes it easier for system to be extended and integrated with the other technologies and applications distributed over the Internet. Using CORBA as a communication architecture, we developed hardware base, Web user management server, task-level robot arm control server, live image feedback server, mobile robot control server and iGPS server, which can provide some basic care services to aid the aged and disabled.

A delivery service system employing multiple mobile robots, which enables many users to use the delivery service simultaneously, needs the capability to reliably direct robots to their destinations in an office-like environment. In the preliminary stages of our work, we achieved deadlock-free navigation of such a multi-robot system in a static environment, where obstacles did not move. The next stage, which is presented in this paper, progressed to the robust navigation of a multirobot system in a dynamic environment, where obstacles, such as chairs or people, are moving. To do this, we used two methods. The first method recognizes obstacles by a mark-based vision technique and updates the environmental map with iGPS. The second method is a conventional one that detects unknown obstacles by an onboard laser range finder. To test our navigation methods, we conducted actual multi-robot experiments in an office-like environment.

Because the elderly population is growing while the number of people to take care of them is declining, the aging problem is becoming an increasingly important social issue. Thus, developing an inexpensive support system for these elderly people staying alone at home or small-scale distributed facilities is becoming particularly important. The paper proposes a basic platform design of a network distributed telecare robotic systems using CORBA as communication architecture, which has high scaling and inter-operating ability that allows the different support groups to make their own independent computing decisions to develop their applications. It also has remote accessibility for caregivers, and the other helpers from any location where a Web browser is available. Using the developed platform, we implemented a task-level robot arm server, a mobile robot control server, and a live image feedback server, which realized some basic telecare services for the aged and disabled.

We attempt to induce a quadruped robot to walk dynamically on irregular terrain by using a neural system model consisting of a central pattern generator (CPG) and reflexes. In this paper, we report on a newly developed quadruped robot, which contains a mechanism designed to make adaptive 3D space walking (pitch, roll and yaw planes) on irregular terrain be performed more simply. In 3D walking, a rolling motion is naturally generated in most gaits. By having the rolling motion be the standard oscillation and making the CPGs of the legs be entrained with a rolling motion, we realized the stabilization of the gait at a constant walking speed, in spite of an unbalanced gravity load between the fore and hind legs. We also realized an autonomous gait transition in changing walking speeds, by utilizing such rolling motion feedback to CPGs, in order to reduce energy consumption. Rolling motion feedback to CPGs contributes to gait stabilization in walking on an irregular terrain as a tonic labyrinthine reflex for rolling. At present stage, the robot succeeded in walking over several 2D irregular terrains by using CPGs, a flexor reflex and tonic labyrinthine reflexes for pitching and rolling.

Tracking a target robustly by utilizing vision is very difficult for a mobile robot running over the irregular terrain of a natural environment, due to the image deformation caused by the rolling and pitching of the camera, as well as due to the relative movement between the target and the camera. One approach for coping with such problems is matching the target image with many affine-transformed candidate images while tracking. However, when the number of candidate images increases significantly, such an approach is not practical to real-time tasks due to the high computational cost involved. In the present paper, we propose a new system called robustness analysis for tracking (RAT) that improves tracking ability. RAT is an analysis based on the features of the object image, in which three parameters - detectability, robustness for depth and robustness for rotation - are defined. Many more robust templates can be found by analyzing the object image using RAT before the tracking task is performed. The experimental results are shown to verify the effectiveness of this method.

Because the elderly population is growing while the number of people to take care of them is declining, we propose an Internet telerobotic system to assist the aged or disabled in their homes when their caregivers are away. We analyze typical teleoperation robotic systems and design an Internet telerobotic system using CORBA . We detail the system's features, architecture, and implementation. The proposed system gives users the ability to control the robotic system remotely by an intuitive user interface. The client can transparently invoke methods on the application servers across the network without knowing where the application servers are located, what programming language the application is written in, or what operating system is being used. This is because, in developing and implementing the system, CORBA for the distributed, object-oriented applications was used.

We propose a practical method of multiple mobile robot navigation aimed at the realization of service robots that deliver letters, parcels and documents in an office building. For robust execution of delivery tasks by mobile robots, navigation is important, and localization of robots is a key function for designing robust navigation. We developed a global positioning system for indoor mobile robots by using cameras distributed in the robots' working domain. This system can execute fast and accurate localization of mobile robots. By integrating the positioning system with a deadlock free navigation algorithm for multiple mobile robots, we implemented a successful autonomous service robot system.

We are trying to induce a quadruped robot to walk dynamically on irregular terrain by using a neural system model. In our previous study, we integrated several reflexes into a CPG (central pattern generator) and realized adaptive 2D walking on terrain of medium degree of irregularity. In this paper, in order to make the role of a CPG be clear, we investigate the relation between parameters of a CPG and the mechanical system by simulations and experiments. In addition, we show a newly developed quadruped robot, of which mechanism is designed to make adaptive 3D walking on irregular terrain be realized more simply. At this moment, 3D walking on flat terrain is realized by using a neural system model consisting of CPG and reflexes.

Proposes task-based data exchange for teleoperation systems through a communication network as an efficient method of transmitting data between an operation device and a remote robot. On the task-based data exchange, the more important information according to the contents and conditions of the task which the robot performs is given transmission priority, for example, by altering the contents of the transmitted data. We have built an experimental system in which the master arm in Tsukuba and the slave arm in Kawasaki, separated by, about 100 km, are connected through N-ISDN and the standard techniques are utilized, such as TCP/IP, socket, JPEG, etc. A series of experimental tasks has been effectively carried out by the task-based data exchange, that is, crank operation which consists of grasping and revolution. The communication network with capacity limitations was used effectively, and the high maneuverability in real-time with bilateral servo control has been realized. The effectiveness of the task-based data exchange has been confirmed.

Introduces a methodology that will allow robots to execute tasks autonomously and with a high degree of success. Taking as an example the mobility of a robot without collision in a dynamic environment, a task-level feedback control system is proposed. The key idea is to incorporate the real-time recognition and motion planning functions into the task control loop. For real-time recognition of the environment, mark-based vision is used. In addition, algorithm to do a global motion planning in the environment where movable obstacles exist is proposed. By integrating the real-time recognition and motion planning, we succeed in forming a control loop, for a robust and deadlock free navigation.

In this paper, remote robot collaboration using a network with communication time delay is discussed in multi-operator-multi-robot (MOMR) teleoperation. Recently, collaboration tasks have rapidly emerged in many possible applications such as plant maintenance, construction, and surgery, because multi-robot collaboration would have a significant advantage over a single robot in such cases. Problems and several noticeable results have been reported in a single-operator-single-robot (SOSR) teleoperation system. However, the effect of time-delay would pose a more difficult problem to the MOMR teleoperation systems and seriously affect their performance. In this work, first, some of the constraints on performance in MOMR teleoperation applications are examined. Then, the time-delay effects on tele-collaboration are investigated through several experimental studies. Finally, a method to cope with the time-delay in MOMR teleoperation systems is proposed exploiting the virtual thickness modification scheme.

We have been developing prototypes of teleoperation systems via a standard protocol with a standard human interface, where VRML2.0 is employed as the protocol and a Web browser as the human interface. Using a Web browser, an operator can plan motions of objects interactively on a manipulation simulator with a world model which was sent from a remote site via VRML. The employment of a standard protocol and human interface enables our teleoperation system to be used by non-specialists from any Internet site, or by anyone from anywhere, without installing any specific software on the client side a priori.

We have developed a teaching system based on the assumption that the assembly task is a series of operations for achieving a target contact state among objects through changing their contact states. The features of our system are as follows: 1) teaching data for fine motion is extracted from a demonstration by an operator in a virtual world, 2) the operator can edit intermediate expressions on a display, 3) intermediate expressions can be used by any robot system with a skill library which has the ability to achieve the corresponding contact states. This paper describes the configuration of the system, program generation using intermediate expressions and a skill library to achieve each contact state.

Since general automatic assembly motion planning using a geometric CAD model is computationally difficult, automation of a general assembly task is not feasible. However, if a human operator roughly specifies an assembly motion, the remainder of the process except for planning can be automated. We construct a teaching system for assembly tasks according to the above concept. This paper describes our teaching system for assembly tasks by using a position/force simulator. We show how to construct the position/force simulator and analyse the hybrid position/force control which is needed when dealing with general rotational motion. We show the example of extracting a sequence of contact state transitions from the motion which the operator performs in the position simulator of our system. The sequence of contact states automatically extracted from the motion shown by the operator makes it feasible to achieve an error-tolerant automated assembly motion. If a sequence of contact states is obtained, studies of the automatic assembly task system can progress based upon this information.

Investigates motions of a polyhedron in contact with a fixed polyhedron under the frictionless assumption. The authors propose a complete algorithm for determining possible velocity of the moving polyhedron and force applicable from the moving one to the fixed one automatically from their geometric models. The algorithm consists of two parts. The first part derives the constraints for the velocity of the moving polyhedron from their shape descriptions. The constraints are represented by linear inequalities of the velocity. The algorithm is complete in the sense that it can be applied to any case in which polyhedra with arbitrary shapes are in contact with arbitrary state. It includes the degenerate case in which a vertex contacts another vertex or edge. The second part solves the inequalities and obtains the set of possible velocity vectors of the moving polyhedron. The authors prove that this part is equivalent to the algorithm for enumerating all vertices of a compact polytope in higher dimensional space. The solution is the direct sum of a nonnegative linear combination of the vectors that break the contact state and a linear combination of the vectors that maintain the state. The minimum set of force vectors that are applicable from the moving polyhedron to the fixed one can be obtained from the set of possible velocity vectors of the moving one. The algorithm is fully implemented in an object-oriented lisp with a solid modeler and in C. The possible applications of the algorithm are also presented.

A model-based robot system is described. This system was developed to replace and improve upon the conventional robot control scheme of teaching-by-showing and replay. The key concept of this system consists of the combination of manipulation skills with an environment model. The model provides the geometric structure and the physical properties of the objects in the environment. Manipulation skills enable reliable task execution in the presence of unavoidable errors and uncertainties. Skills are implemented within the hybrid position/velocity/force control scheme and incorporate sensing procedures to detect the state to be achieved. An experiment involving the disassembly of a valve using this system is presented.>

A model-based robot system is described. This system was developed to replace and improve upon the conventional robot control scheme of teaching-by-showing and replay. The key concept of this system consists of the combination of manipulation skills with an environment model. The model provides the geometric structure and the physical properties of the objects in the environment. Manipulation skills enable reliable task execution, in the presence of unavoidable errors, and uncertainties. Skills are implemented within the hybrid position/velocity/force control scheme and incorporate sensing procedures to detect the state to be achieved. An experiment involving the disassembly of a valve using this system is presented.>

This paper presents a general algorithm for derivation and analysis of motion constraints of objects in contact. The constraints can be derived as linear inequalities for a general case, even when a vertex contacts another vertex or an edge. The solution of the inequalities is a direct sum of a nonnegative linear combination of motions which change the contact state and a linear combination of them which maintain it. From the singular value decomposition of the coefficient matrix of the inequalities it is possible to find the solution in the minimal dimensional space, where the complexity of the algorithm is also minimal. An algorithm is proposed which is not optimal as asymptotic complexity, but is fast in the practical cases and uniform for the dimension of the cone. The algorithm presented can be applied not only to the sensing and control of motion in contact, but also to the planning of it.>

A structured programming and teaching system is described for a robot manipulator where stress is laid on the consistent integration of programming and teaching. In the PAL programming system being developed at Purdue University, tasks are represented in terms of structured Cartesian coordinates. Every motion statement is a request to position and orient the manipulator such that a position equation, representing a closed kinematic chain of homogeneous transformations, is satisfied. In the teaching process, the transformation which represents the position of the end of the manipulator is defined using the manipulator itself, and an equation relating any undefined transformations is obtained. By defining these equations during the interpretation of the task program and progressively solving them, the task is taught. The method is applicable both to practical industrial robot control and to intelligent robot control.

This paper describes a structured programming and teaching system for a robot manipuLator where stress is Laid on the consistent integration of programming and teaching. Tn the PAL programming system being developed at Purdue, tasks are represented in terms of structured Cartesian coordinates. Every motion statement is a request to position and orient the manipulator such that a position equation, representing a closed kinematic chain of homogeneous transformations, is satisfied. In the teaching process, the transformation which represents the position of the end of the manipulator is defined using the manipulator itself, and an equation relating any undefined transformations is obtained. By defining these equations during the interpretation of the task program and progressive by solving them, the task is taught. The method is applicabLe both to practical industrial robot control and to intelligent robot control.