Interior singularity analysis for a 2(3HUS+S) parallel manipulator with descending matrix rank method

Singularity analysis is one of the basic problems for parallel manipulators. When a manipulator moves in a singular configuration, the motion and transmission performance are poor. In certain serious cases, the normal operation could be damaged. Based on the topology structure and kinematics analysis of a 2(3HUS+S) parallel manipulator, the Jacobian matrices were established. Then, the singular locus surface was obtained by numerical simulation. In addition, the relationship between the motion path curve and the singular locus surface was analyzed. In this study, α, β, and γ are the attitude angles that describe the motion of moving platforms. There is a nonsingular attitude space in singular locus surfaces, and the singular locus surface is a single surface in a small attitude angle range. The nonsingular attitude space increases as the absolute value of γ increases, and singularity could be avoided when γ is large. Furthermore, the motion path curve passes through the singular locus surface two times, and the two intersection points are consistent with the positions where the motion dexterity is equal to zero. This study provides new insights on the singularity analysis of parallel manipulators, particularly for the structure parameter optimization of the nonsingular attitude space.

Simulation of kinematic and workspace analysis of 3-PRS parallel manipulator

In the present era, the competitive producers are forced to use maximally newer advanced technology and its effective fast implementation using various available tools for synthesis of new product requirement. Use of current state of art computer aided technology supports the creation of flexible assemblies and their built up though unified modular approach. The design of robotic mechanism is a complex process involving geometric, kinematic, singularity analyses during its synthesis phase. The present work is aimed at the effective utilization of CAx system Pro/Engineer tools for creation, ease in modification and analysis of spatial parallel manipulator. Three degrees of freedom of 3-PRS parallel manipulator is obtained using mobility analysis. Parallel manipulator with 3-DOF with 3-PRS configuration is investigated. The kinematics simulation of the robot is carried out using mechanism simulation and compared with closed form solutions. The concept of reachable, orientation and dexterous workspace is expressed. Tool tip coordinates obtained through simulation are plotted for workspace development. Inner and outer workspace boundaries are developed and analyzed for four different cases to understand the problem of interior singularity within workspace.

Kinematic Analysis of a 2-DOF Planar Parallel Manipulator with Automated Selective Activation Mechanism to Avoid Singularities

Parallel Manipulator has lot of applications in areas like flight/automobile simulators, earthquake simulators, milling machine, etc. Main disadvantage of parallel manipulator is the presence of singularities within the workspace. Due to this, entire workspace of a parallel manipulator cannot be used effectively. To overcome this disadvantage, an automated selective activation mechanism is proposed, designed and fabricated using solenoids, gear train and belt drive arrangement. By using this mechanism interior singularity are crossed and this enables the user to utilize the entire workspace. Selective activation mechanism with automation ability is designed in such a way that, depending on activation of solenoid, active joint of manipulator changes from one position to another, which subsequently changes the singularity curves. By changing active joint positions, 4 ways of operating manipulator are identified. For all type of operations, singularity curves are plotted using MATLAB.