Papers by Keyword: 3-DOF

Abstract: The forearm is a typical ball and socket joint which have three degrees of freedom rotation. In this case the study of a 3-DOF manipulators is very interesting. In this paper, a novel manipulators based on 3-DOF orthogonal spherical parallel mechanism is proposed. Error analysis play an important role on the design and applications of the manipulators. The error model is derived in closed forms by using differential theory. Error evaluation index is defined. Terminal platform error distribution is analyzed and discussed in detail by using the error model technique. The analytic results indicate error value is smallest in initial position of the manipulators,the bigger value of error distributes in the workspace edge. So, this paper could provide a theoretical foundation for design and application of the manipulators.

Abstract: In this paper, a novel 3-degree-of-freedom (DOF) parallel manipulator that can perform three rotations around the remote centre is presented. The theory of screws and reciprocal screws is employed for the analysis of the geometric conditions. In particular, using circular guide to instead of R joints, so that has the advantage of enabling continuous 360° revolute around Z-axis. The inverse kinematics of mechanism is given and the workspace has a good performance. To compare with the machine constructed with traditional joints, it has the advantage of high rigidity and precision.

Abstract: A friction-free planar motor, which is composed of piezoelectric elements (piezos), is proposed. The motor is based on the principle of an inchworm using levitation mechanisms. The vertical vibration of the piezo generates the levitation force of the motor. The horizontal deformation of the piezo causes the thrust force of the motor. These piezos realizes three degree-of-freedom motion on a flat surface. We measure the displacement in the vertical and horizontal direction of the levitation mechanism. The feasibility of the inchworm using levitation mechanisms is described.

Abstract: Hybrid-driven mechanism synthesis the constant speed motor and the servo motor as the power source through a multi degree of freedom mechanism. The text study on the trajectory planning of hybrid-driven planar 3-RRR mechanism. Firstly, based on compatible link combinations, all possible basic configurations of planar 3-dof kinematics chains were derived. Based on the requirements of hybrid-driven mode, the kinematics chains were selected one by one Planar 3-RRR mechanism was determined to be the research object finally. Then, based on the conclusions of inverse kinematics analysis, using the cubic spline function on point to point path planning, the servo motor rotation laws were presented. Comparing the different speed situation of constant motor, the influence trends on planning results were analyzed.

Abstract: 3-dof wire-driven parallel mechanism is studied in this research. The kinematic analysis of this wire-driven parallel mechanism is given according to analytical method. The method for spline function is proposed to generate a continuous, smooth and noiseless trajectory of the wire. The simulation results, based on simulink, verify the rationality of this trajectory planning algorithm

Abstract: This study proposes a 3-axis AC servo motor parallel platform with intersecting rails. The 3-actuators are designed to be horizontally on the base platform with their extensions intersect in the base platform center. The forward kinematics, inverse kinematics and work space of this mechanism are established and the singularity distribution is investigated. Optimal maneuvering regions are recommended from the viewpoints of singularity and stiffness.

Abstract: The paper reports on the main assumptions and guidelines regarding construction of a novel type of parallel micro-robot with 3 degrees of freedom. Such micromanipulator is a hybrid construction, consisting of three arms connected together in parallel structure. The mechanical construction is a combination of rotational joints with bearings and flexible compliant joints so called: flexures. The whole construction measures several cubic centimeters and operates within c.a. 4 cubic centimeters workspace. In addition, the article relates to selected aspects of the control system, mathematical analysis of kinematics, basic simulations, specification of the range of movement of all actuators, and workspace of the moving platform. Modeling flexures using FE method will also be presented.

Abstract: Parallel mechanisms could be hardly used in contour tracking because of their mechanism features. This study proposed a link-space real time contour tracking for a 3 DOF (Z、α and β) hydraulic parallel mechanism. The essence of this approach is to convert control points of command trajectory to link space by inverse kinematics. A real-time interpolator was created and the multi-axis cross-coupled pre-compensation control (MCCPM) was constructed for link-space contour tracking. It was shown that a contour-accurate trajectory tracking could be performed which was impossible in the original Z-α-β space. Other advantages of this link-space approach were time efficiency and the uniform tracking velocity.