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Hydraulic Manipulator Shoulder Module

V. Hayward Parallel mechanisms may provide for structural rigidity and good dynamic performance, however their utility is generally limited by an inherently small workspace. The use of actuator redundancy can simultaneously increase the workspace and remove singularities. A novel method to perform multi-goal optimization has been devised to determine the set of optimal and realizable designs. Following this principle, a prototype of a 3 DOF spherical joint module, the ``shoulder'' for a light-weight robotic arm has been built. (See Figure 26). It is powered by four high-performance hydraulic actuators. The joint develops 200 Nm of torque around any direction with a supply pressure of 4 MPa and has a moving mass of less than 1 Kg. The torque control bandwidth exceeds 50Hz. Patent pending. This joint is currently being redesigned for optimal structural properties by Prof. L. Lessard and his co-workers (Mechanical Engineering). An elbow joint with two actuators is also being designed and constructed, taking advantage of advanced composite materials. [shoulder.eps].55 Hydraulic shoulder modulehayward:figure18



Thierry Baron
Mon Apr 7 12:54:24 EDT 1997