Browsing by Author "Denizli, Mustafa Semih"

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Citation - Scopus: 3
On the Stability of Inverse Dynamics Control of Flexible-Joint Parallel Manipulators in the Presence of Modeling Error and Disturbances
(Tubitak Scientific & Technological Research Council Turkey, 2019) Korkmaz, Ozan; Denizli, Mustafa Semih; Ider, Sitki Kemal; 108608; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Inverse dynamics control is considered for flexible-joint parallel manipulators in order to obtain a good trajectory tracking performance in the case of modeling error and disturbances. It is known that, in the absence of modeling error and disturbance, inverse dynamics control leads to linear fourth-order error dynamics, which is asymptotically stable if the feedback gains are chosen to make the real part of the eigenvalues of the system negative. However, when there are modeling errors and disturbances, a linear time-varying error dynamics is obtained whose stability is not assured only by keeping the real parts of the frozen-time eigenvalues of the system negative. In this paper, the stability of such systems is investigated and it is proved that the linear time-varying system can be rendered stable by selecting the feedback gains such that the variation of the system becomes sufficiently slow. To illustrate the performance of the control method, deployment motion of a 3-(R) under bar PR planar parallel manipulator subject to impact is simulated. For the impact model, the impulse-momentum and the coefficient of restitution equations for the system are derived.
Trajectory tracking control of flexible joint parallel manipulators subject to impact
(2016) Denizli, Mustafa Semih; 01. Çankaya Üniversitesi
In this study, trajectory tracking control method for parallel manipulators having joint elasticity is examined and in addition the stability and the performance were investigated when the manipulator is subject to an impact with another object. Firstly, dynamic analysis for the parallel manipulators is carried out and the system equations of motion are derived by using Lagrange technique. Then the system impulse-momentum equations are derived. Moreover, an inverse dynamics control method is presented which is based on an input-output relation between the torques and end-effector position variables. In the case study, a 3-RPR planar parallel manipulator with three legs having joint elasticity is simulated considering an impact with a point mass body and all of these simulations are conducted by Matlab® and Simulink® software programs. After the simulations, it is observed that controller retrieved the desired trajectory and the results are provided at the end of the study.