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BACKGROUND In a patient with severe hemiplegia, the risk of the knee giving way is high during the early stage of gait exercise with an ankle-foot orthosis. However, use of a knee-ankle-foot orthosis has many problems such as large amount of assistance and compensatory motions. To resolve these problems, we have engaged in the development of the Gait Exercise Assist Robot (GEAR). OBJECTIVE To evaluate the improvement efficiency of walk with GEAR in a stroke patient. METHODS The subject was a 70-year-old man presented with left thalamus hemorrhage and right hemiplegia. The patient underwent exercise with the GEAR 5 days a week, for 40 minutes per day. We evaluated the Functional Independence Measure score for walk (FIM-walk score) every week. The control group consisted of 15 patients aged 20-75 years with hemiplegia after primary stroke, who had equivalent walking ability with the subject at start. As the primary outcome, we defined improvement efficiency of FIM-walk, which was gain of FIM-walk divided the number of required weeks. RESULTS Improvement efficiency of FIM-walk of the subject was 1.5, while that of control group was 0.48±3.2 (mean±SD). CONCLUSIONS GEAR is potentially useful for gait exercise in hemiplegic patients.

Traditionally, robots and humans work independently, isolated from each other for safety reasons. We developed a robot for use on the assembly line which works together with a human operator, assisting and augmenting the operator's skills. Because of its function, this robot is known as the “Car Window Installation Assist Robot” and is currently in use on the plant of Toyota Motor Corporation. In this paper, we propose a method to estimate human intent as well as a skill assist control method. Moreover, we present technology that enables safe human-robot cooperation, high product quality, and the cycle time of only 48 seconds.

Industrial robots have been widely used in factory automation. On the other hand, in the final assembly in automobile factories, many tasks are still completed by humans due to the difficulties and costs associated with automation. One example still requiring skilled human operators is the installation of the automobile window. The window installation assist robot we developed enables a single operator to install a window easily. The present study focuses on kinesthetic assistance including preliminary experiments and application to automobile window installation during car assembly demonstrating the effectiveness of our proposal.

In the social context of an aging workforce in the labor intensive manufacturing sector, we discuss an assistance system for older workers (mainly in their 40's and 50's) who have excellent skills though their physical ability to perform iterative tasks at a constant speed with high quality over one eight hour shift has declined. "Skill-Assist" which is proposed in this paper is a new type of assisting system which varies its mechanical impedance to give workers who have been working under the lifetime employment system a sense of achievement in being again able to accomplish the skilled tasks they were capable of when younger. This paper discusses the control algorithm of Skill-Assist based on variable impedance control. First, a criterion for varying the impedance of Skill-Assist in response to task condition variations is explained. Second, impedance patterns experimentally determined to be desirable are discussed. These patterns are those required to produce a good subjective operational feel when maneuvering Skill-Assist and precise positioning based on the criterion for varying the impedance. Finally, the control algorithm of Skill-Assist is presented. This algorithm is estimated based on the subjective operational feel, physical stress, and productivity of one selected iterative positioning task.