In recent years, there is an increase in the number of people that require support during walking as a result of a decrease in the leg muscle strength accompanying aging. An important index for evaluating walking ability is step length. A key cause for a decrease in step length is the loss of muscle strength in the legs. Many researchers have designed and developed orthoses for walking assistance. In this study, we advanced the design of an orthosis for walking assistance that assists the forward swing of the leg to increase step length. We employed a pneumatic artificial muscle as the actuator so that flexible assistance with low rigidity can be achieved. To evaluate the performance of the system, we measured the effect of assistance quantitatively. In this study, we constructed a prototype of the orthosis and measure EMG and step length on fitting it to a healthy subject so as to determine the effect of assistance, noting the increase in the obtained step length. Although there was an increase in EMG stemming from the need to maintain body balance during the stance phase, we observed that the EMG of the sartorius muscle, which helps swing the leg forward, decreased, and the strength of the semitendinosus muscle, which restrains the leg against over-assistance, did not increase but decreased. Our experiments showed that the assistance force provided by the developed orthosis is not adequate for the intended task, and the development of a mechanism that provides appropriate assistance is required in the future.

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An outline of the developed system for autonomous loading operation by wheel loader will be described. The system consists of three subsystems: (1) Environment measuring and modeling, (2) Planning and (3) Motion control. The environment measuring subsystem measures 3D shape of the environment by stereo-vision system. The shape of the pile is converted into the environment models. The planning subsystem determines the position and direction of scooping on the pile based on the environment models. It generates the V shape path between the scooping point and the loading point as well. The motion control subsystem controls actuators on the loader based on the reference values from the planning subsystem in traveling on the V shape. However the motion of the bucket at scooping is controlled based on the resistance force applied on the bucket during scooping motion. The developed system is installed on an experimental small size scale model in lab and on a real wheel loader in the experimental field.

A control method of positioning a serial link manipulator suspended by a crane type robot with multiple wires is proposed. The manipulator is fixed on a base plate suspended by three wires. Since the manipulator is suspended by wires, the position and orientation of the base may change according to external forces applied to the manipulator or the change of the manipulator pose. Thus, the inverse kinematics becomes very complicated, and moreover, the mechanism does not seem to be suitable for tasks requiring manipulator tip forces. In this paper, it is shown that the inverse kinematics becomes very simple by using a redundant D.O.F. manipulator, and a method of exploiting the manipulator for tasks requiring forces is described.

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