We have been developing a new mobility device, Tread-Walk 2, which supports walk for elderly people. This paper describes a mechanical model which considers friction forces of the treadmill to improve the operability of Tread-Walk 2. As a first step, an anteroposterior force is estimated using motor current value. By comparing the estimated anteroposterior force using motor current value with the measured one using force plate, the waveform pattern of the estimated anteroposterior force was similar with that of the measured anteroposterior force in two young subjects whose physical characteristics were quite different.
The purpose of this research is to discriminate many motions using EMG signal for prosthetic application's control. The basic idea of this study is that, the current degree of proficiency, i.e., how well the application is operated by a user is to be analyzed from bio-signal closely related to human motor process, and control rule is generated depending on the proficiency level. Thus, our proposed system consists of two parts: estimation of user's proficiency level using EMG signal, and motion classification using self-organized clustering. In the experiment, users trained to discriminate motions using our proposed system, and then they all were able to discriminate seven forearm motions with approximately 90% accuracy. In addition, one of the users was able to discriminate nine motions with 21% higher accuracy than before training. The results indicated the effectiveness of proposed system.
We have developed the probe scan mechanism for echography using pneumatic actuators. First we established a driving system of the actuator by driving an electro-pneumatic control valve to examine the relationship between force and pressure. Then we constructed the mechanism to be put on patient abdomen by arranging six actuators around the probe to realize five degrees of freedom including the press motion of the probe. Total weight of the mechanism could be set less than 700[g]. Next we established feedback control method of both of position and pressure in the probe. Because the contact force on body surface cannot be measured directly, we have applied an estimation control in contact force from inner pressures of actuators to realize maximum error of 25% in the contact force.
This paper proposes a method of wheelchair's step climbing using a wheeled robot which has two manipulators. The robot, TATEYAMA, has been developed to assist wheelchair users. In step climbing, the wheelchair and the robot are connected by the manipulators, and the shoulder and elbow joints of the manipulators are passively controlled. As it is important to control the link angle for the safe step climbing, we perform a numerical calculation to clarify its requirements. The system uses the robot's body to pin the passive rotary motions of the shoulder links during the pushing motion of the wheelchair. We ascertain the effectiveness of this method by the experiments.
The aim of this study is the development of a biocompatible tactile sensor for measuring softness, sliminess, smoothness, and so on. We have proposed active tactile sensing method using balloon expansion. A balloon is contacted with an object and expanded by using fluid. Tactile information is evaluated by measuring the expansion process. In this paper, we develop a sensor system using a syringe. It is a compact system and can ensure enough safety for human body tissues by sterilization and using no electric power. Pressure changes and volume changes of the balloon can be measured together in the expansion. First, overview of the developed sensor system is presented. Next, composition of the sensor system and the sensing process are presented. Then, experiments using the developed sensor system are conducted on samples with different stiffness and surface conditions. Features extracted from sensor outputs can discriminate the samples and have clear correlations with stiffness and sliminess. The results show the validity of the proposed sensor system.
Growing garden products involves a lot of work, such as harvesting, which is difficult to mechanize. Garden product crops require longer working hour compared with rice. We are developing a robot performing soil sterilization aimed at preventing repeated cultivation disorder. This robot is a medicinal solution injection robot injecting chloropicrin to use for soil sterilization automatically. The developed robot is driven by oil pressure actuators, runs on crawlers, with an chemical injector mounted in front of the robot. The robot is equipped with a gyroscopic sensor and a triangular surveying sensor. The robot covers entire working soil area with a combination of straight lines along which the position and orientation of the robot is compensated by the output from the sensors. Experiments were conducted to demonstrate that the robot can navigate on the uneven and soft terrain within required position errors.
The service robot technology is facing the pre-dissemination phase. In this paper, we clarify that a new robot service platform requirement for that phase is the remote interrupted operation, in addition to the requirements discussed in the previous paper. And we clarify also a requirement for supporting the robot service development. To solve these requirements, we propose the command profile and a robot service execution/development environment on the internet which is consist of RSNP library, real robot services such as a disaster prevention information service and a monitor service, RSi server, and RSI robot portal site. And we show our proposals are effective.
This paper proposes a system configuration method to realize a robot system which can perform daily-use object storage and management service in a living space. In the method, compliant mechanisms are utilized proactively to overcome position/posture errors and deviations in measurement or control phases. To validate the proposed system configuration method, we developed a home-use container transfer robot that is installed with (1) robust container handling mechanisms implemented by crank shafts and (2) passive compliant mechanisms for horizontal and inclination misalignment. The robot was integrated with a container position measurement system to perform experiments. Experiments confirmed that a robust container transfer motion can be realized without complex feedback measurement and control processes. Several key design points are also described to leverage mechanical compliance.
The development of cybernetic human HRP-4C is presented in this paper. The word “Cybernetic Human” is a coinage for us to explain a humanoid robot with a realistic head and a realistic figure of a human being. HRP-4C stands for Humanoid Robotics Platform-4 (Cybernetic human). Standing 158[cm] tall and weighing 43[kg] (including batteries), with the joints and dimensions set to average values for young Japanese females, HRP-4C looks very human-like. This paper introduces the project overview, the design process, mechanical features, and electrical features with specifications of HRP-4C.
In this paper, we show a high power prototype biped robot for application of nursing or running or jumping motions. Light and powerful actuators are required to realize the high-power performance. We propose a method to bring out maximum performance of electric motors aggressively. The technique of motor core temperature estimation and control improves the motor power performance dramatically but safely without motor burnout. High power acctuator system and robust interbody network are depeloped for high power robot. Fundamental demonstrations of high power motion are shown.
We propose track-changeable quadruped walking robot, named “TITAN X”. TITAN X is a novel leg-track hybrid mobile robot with a special leg driving system on each leg. Driving belt on each leg changes to a timing-belt in leg form and a track-belt in track form. TITAN X walks in leg form on rough terrain and makes tracked locomotion using track-belt on level or comparatively low-rough terrain. The characteristics of TITAN X are: 1) it has a hybrid function but is lightweight, 2) it has potential capabilities to demonstrate high-performance on highly-rough terrain. In this paper, details of leg design with special belt are reported. Also form change mechanism are integrated into the system. We have constructed prototype of TITAN X and successfully demonstrated basic performance of TITAN X and the validity of the concept of a track-changeable walking robot.
The wheel-less active cord mechanism is suitable for moving on rough environment. In this paper, we introduce the new wheel-less active cord mechanism “ACM-R7”. ACM-R7 has dust and water proof property. The coupled drive mechanism is installed to the joint mechanism, which enlarge output torque and motion range of the joint angle. In addition, the new control method of Loop-Gait locomotion was also developed. The new loop shape “Serpenoid-oval” and the steering control method ware proposed. These control methods were implemented to ACM-R7. ACM-R7 was able to move speedy and freely on the ground with those control methods.
In this paper, a light-weight and high precision anthropomorphic robot hand we developed is discussed. One of the common problems of robot hands is the mechanism of the finger joint. Gears and wires are often used in robot hands, but these mechanisms have demerits like backlash and maintenance. To solve these, we developed a unique 3D cam mechanism and used it in the finger joint of the robot hand. The mechanism can extremely reduce backlash and can also be miniaturized allowing high power transmitting abilities. The robot hand has 20 joints with 16 DOF and the weight is approximately 800 grams. Considering the weight of the hand and the high degree of freedom, it is one of the lightest robot hands in the world. Cutkosky's 16 grasp types was used to verify the versatility and the dexterity of the hand. The results show that the hand is effective and features a high degree of maneuverability.
We propose a new linear actuator, named Spiral-motor, which has more advantage than conventional linear motor. Spiral-motor consists of a mover and a stator with spiral structure. Our first prototype of Spiral-motor has a ball-screw to keep constant air gap between mover and stator, and has surface permanent magnets (SPM). In this paper, we present a new Spiral-motor, which does not have ball-screw and has interior permanent magnets (IPM). Also, we analyze characteristics of the new Spiral-motor by permeance method and finite element method, and consider magnetic levitation control by simulation.
Above their glass transition temperature, shape-memory polymers (SMPs) can be deformed by applying a small load. They maintain their shape after they have been cooled below the glass transition temperature, and then return to a predefined shape when heated above the glass transition temperature. The reversible change in the elastic modulus between the glassy and rubbery states of SMPs can be of the order of 100 to 1000 times. Exploiting these characteristics, this study seeks to evaluate the fundamental performance of a position-keeping module that uses an SMP. When this position-keeping module is warmed above its glass transition temperature, the SMP deforms and the module deforms on applying a small load. After the position-keeping module reaches a desired length, it is cooled to below the glass transition temperature and the SMP can be fixed in a rigid state without supplying electric power. The experimental results of a preliminary proof-of-concept investigation conducted on SMP tubes confirm the feasibility of using an SMP to fabricate a reliable, light and low-cost position-keeping module for a robot arm.