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Universal Cartesian Robot (UCR): H.S. Kim and L.W. Tsai |
This innovative parallel manipulator consists of a fixed base, a moving platform, and three supporting legs. Each limb is made up of one prismatic and three parallel revolute joints. One linear actuator is used to control the motion of each prismatic joint. Furthermore, all joint axes in a limb are parallel to one another and the axes of the three limbs are orthogonal to each other. As a result, each limb provides two rotational constraints to the moving platform and the combined effects of the three limbs lead to a mechanism with three translational degrees of freedom. The three degrees of freedom are completely decoupled.
Patent disclosure: UC Case 2002-139
Prototype UCR
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Three degrees of freedom |
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3 parallel PRRR limbs (No S or U joints) |
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Orthogonal linear actuator arrangement |
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Isotropic everywhere within its entire workspace |
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Decoupled X, Y, and Z motions |
Potential Applications:
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Positioning devices |
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Assembling machines |
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Coordinate measuring machines |
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Multi-axes machine tools |
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Hybrid serial-parallel machines |
Side view
Front view
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Spatial 3-RPS Parallel Manipulators: H.S. Kim and L.W. Tsai |
This project is concerned with the design of spatial 3-RPS parallel manipulators from dimensional synthesis point of view. We have shown that at most six precision positions of the moving platform can be specified arbitrarily and, given six prescribed positions, there are at most ten RPS chains that can be used to construct up to 120 manipulators.
Manipulator synthesized to pass six precision positions.
Manipulator synthesized to pass six precision positions.
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Hybrid Kinematic Machines: S. Joshi and L.W. Tsai |
This project deals with the design and analysis of hybrid kinematic machines. A hybrid kinematic machine typically consists of a 3-DOF position mechanism and a 1 to 3-DOF orientation mechanism that can be arranged in series or in parallel. The kinematics, Jacobian, and stiffness of two classes of 3-DOF parallel positioning mechanisms, one with three and the other with four supporting legs, are studied.
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Structure Synthesis of 3-DOF Translational Platforms: Y. Fang and L.W. Tsai |
This project is concerned with the enumeration of the kinematic structures of general and overconstrained 3-DOF translational parallel manipulators.
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Parallel Hybrid Electric Vehicles: G. Schultz and L.W. Tsai |
This project is concerned with the design of an innovative transmission mechanism for use in parallel hybrid electric vehicles. The transmission can provide five basic modes of operation that can be divided into thirteen sub-modes: one electric motor mode, three power modes, four engine modes, one CVT mode, and four regenerative braking modes. These modes can be grouped into like clutching conditions, providing the functional appearance of a conventional 4-speed automatic transmission.
Patent Pending, Docket No. 08939/00001
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Six-DOF Parallel Manipulator: F. Tahmasebi and L.W. Tsai |
This manipulator consists of a moving platform, a fixed base, and three inextensible limbs. Each limb has a revolute joint on one end and a spherical joint on the other end. Furthermore, the lower end of each limb is connected to a two-DOF driver that can move freely on the base plate.
U.S. Patent No. 5,279,176
A six-DOF NanoStage produced by Adept Technology with a license agreement from Tsai and Tahmasebi
Main Features:
Mini travel: 28 mm: X and Y, 10 mm: Z, +/- 12 degrees in three directions.
Precise incremental motion: 50 nm (X,Y), 25 nm (Z), and 1 micro-rad in three directions.
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Three-DOF Translational Platform: R. Stamper and L.W. Tsai |
A three-DOF manipulator that employs only revolute joints and constrains the moving platform to translational motion was conceived. Both direct and inverse kinematics were solved in closed form. The workspace was optimized and the dynamical equations of motion were derived by using Lagrange's formulation.
U.S. Patent No. 5,656,905, 1997