Inverse dynamics of parallel manipulators in the presence of drive singularities

Ider, SK
At drive singularities of parallel manipulators the actuators lose control of the end-effector in certain directions. It is shown that if certain conditions related to the consistency of the dynamic equations are satisfied by a proper design of the trajectory, the manipulator can pass through the singular positions while the actuator forces and the system motion remain stable. To find the values of the actuator forces in the neighborhood of the drive singularities, the dynamic equations are modified by using higher order derivative information.


Singularity robust inverse dynamics of planar 2-RPR parallel manipulators
Ider, SK (SAGE Publications, 2004-07-01)
In planar parallel robots, limitations occur in the functional workspace because of interference of the legs with each other and because of drive singularities where the actuators lose control of the moving platform and the actuator forces grow without bounds. A 2-RPR (revolute, prismatic, revolute joints) planar parallel manipulator with two legs that minimizes the interference of the mechanical components is considered. Avoidance of the drive singularities is in general not desirable since it reduces the ...
Söylemez, Eres (Elsevier BV, 1993-07-01)
Design of spatial four-bar mechanisms in which the skew crank axes are at right angles is investigated. Using an algebraic approach, the lengths of the moving links are expressed as functions of a single parameter. Transmission optimization of right-angled four-bar mechanisms can then be determined from the solution of a single parameter constrained optimization problem. When the motion is symmetric, mechanism proportions which yield constant force transmission characteristics can be obtained.
Trajectory tracking control of parallel robots in the presence of joint drive flexibility
Ider, S. Kemal; Korkmaz, Ozan (Elsevier BV, 2009-01-09)
Trajectory tracking control of parallel manipulators is aimed in the presence of flexibility at the joint drives. Joint structural damping is also considered in the dynamic model. The system is first converted into an open-tree structure by disconnecting a sufficient number of unactuated joints. The closed loops are then expressed by constraint equations. It is shown that, in a parallel robot with flexible joint drives, the acceleration level inverse dynamics equations are singular because the control torqu...
Tezer, Münevver (Wiley, 1986-09-01)
The magnetohydrodynamic (MHD) flow of an incompressible, viscous, electrically conducting fluid in an infinite channel, under an applied magnetic field has been investigated. The MHD flow between two parallel walls is of considerable practical importance because of the utility of induction flowmeters. The walls of the channel are taken perpendicular to the magnetic field and one of them is insulated, the other is partly insulated, partly conducting. An analytical solution has been developed for the velocity...
Inverse dynamics control of parallel manipulators around singular configurations
Özdemir, Mustafa; İder, S. Kemal; Department of Mechanical Engineering (2008)
In this thesis, a technique for the motion of parallel manipulators through drive singularities is investigated. To remedy the problem of unbounded inverse dynamics solution in the neighborhood of drive singularities, an inverse dynamics controller which uses a conventional inverse dynamics control law outside the neighborhood of singularities and switches to the mode based on the formerly derived modified equations inside the neighborhood of singularities is proposed. As a result, good tracking performance...
Citation Formats
S. Ider, “Inverse dynamics of parallel manipulators in the presence of drive singularities,” MECHANISM AND MACHINE THEORY, pp. 33–44, 2005, Accessed: 00, 2020. [Online]. Available: