(OBLIX, 1978-79) (MOGURA, 1982-84). In order to make a hyper-redundant arm to move three dimensionally, a light weight and high output segment drive mechanism is required. The oblique swivel joint arm is a mechanism that alternately connects oblique swivel joints, which rotate around the axis that forms angle a from the central axis of the arm, and a coaxial swivel joint as indicated in Fig. 1, . The oblique swivel joint is regarded as a segment that executes bending movement of +-2a based on cooperative control with the neighboring two coaxial swivel joints.

This oblique swivel mechanism can be designed with compact segments. It also can have an exoskeleton shape forming a shell, and this can lessen the weight and heighten the rigidity. Photo. 1, shows a three dimensional movement experiment based on the OBLIX. Photo. 2, shows a running experiment based on the OBLIX which has been equipped with drive wheels. There is a total of 16 segments; an overall length of 1.6 m; and a total weight of 4.3 kg.

Photo. 3, is the MOGURA arm which utilizes an oblique swivel mechanism developed in cooperation with Toshiba Co. After casting a water wheel for hydroelectric power generation with a diameter of about 4-5 m, this is the arm that performed the grinder finishing of the water runners that follow along the fins of the interior part. Until this time, workers climbed into the curving runners to measure the surface conditions and do the grinding as shown in Fig. 2, . The MOGURA is a oblique swivel mechanism that forms a compact and highly rigid arm, and it can bring about the kind of system shown in Fig. 3, . The total length is 2.5 m, the diameter is 200 mm, and the oblique swivel angle a is 15[deg].