Position Control of a 3-RRR Planar Parallel Manipulator with Non-Planar Links Using External Encoders

2014 ◽  
Vol 971-973 ◽  
pp. 1280-1283 ◽  
Author(s):  
Anjan Kumar Dash ◽  
Sai Krishnamurthy ◽  
Shyam Prasadh ◽  
Vishanth Sundar
Keyword(s):  
Motion Control ◽  
Horizontal Plane ◽  
Parallel Manipulator ◽  
Position Control ◽  
Bending Stress ◽  
Planar Parallel Manipulator ◽  
Payload Capacity ◽  
Position Feedback ◽  
Novel Method ◽  
At Home

A Planar Parallel Manipulator (PPM) with non-planar links overcomes most of the shortcomings in conventional manipulators. Due to cantilever action, the links of a PPM develop bending stress. When the links are non-planar (having inclination with the horizontal plane), this cantilever action reduces and the same manipulator can have higher payload capacity. In this project, a planar 3-RRR manipulator with non-planar links is investigated for rectifying singularity at home configuration, and a novel method of position feedback of the motor is designed, fabricated and tested with rest of the motion control components.

scholarly journals SINGULARITY ANALYSIS OF A 3-PRRR KINEMATICALLY REDUNDANT PLANAR PARALLEL MANIPULATOR

1970 ◽  
Vol 41 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Soheil Zarkandi
Keyword(s):  
Motion Control ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Singularity Analysis ◽  
Redundant Manipulators ◽  
Static Behavior ◽  
Singular Configurations ◽  
Planar Parallel Manipulator ◽  
And Control ◽  
Planar Parallel Manipulators

Finding Singular configurations (singularities) is one of the mandatory steps during the design and control of mechanisms. Because, in these configurations, the instantaneous kinematics is locally undetermined that causes serious problems both to static behavior and to motion control of the mechanism. This paper addresses the problem of determining singularities of a 3-PRRR kinematically redundant planar parallel manipulator by use of an analytic technique. The technique leads to an input –output relationship that can be used to find all types of singularities occurring in this type of manipulators.Key Words: Planar parallel manipulators; Redundant manipulators; Singularity analysis; Jacobian matrices.DOI: 10.3329/jme.v41i1.5356Journal of Mechanical Engineering, Vol. ME 41, No. 1, June 2010 1-6

scholarly journals Experimental and Numerical Study on the Semi-Closed Loop Control of a Planar Parallel Robot Manipulator

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yong-Lin Kuo ◽  
Tsu-Pin Lin ◽  
Chun Yu Wu
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Parallel Manipulator ◽  
Position Control ◽  
Robot Manipulator ◽  
Numerical Study ◽  
Research Work ◽  
Loop Control ◽  
Dc Motors ◽  
Planar Parallel Manipulator

This paper implements the model predictive control to fulfill the position control of a 3-DOF 3-RRRplanar parallel manipulator. The research work covers experimental and numerical studies. First, an experimental hardware-in-the-loop system to control the manipulator is constructed. The manipulator is driven by three DC motors, and each motor has an encoder to measure the rotating angles of the motors. The entire system is designed as a semiclosed-loop control system. The controller receives the encoder signals as inputs to produce signals driving the motors. Secondly, the motor parameters are obtained by system identification, and the controllers are designed based on these parameters. Finally, the numerical simulations are performed by incorporating the manipulator kinematics and the motor dynamics; the results are compared with those from the experiments. Both results show that they are in good agreement at steady state. There are two main contributions in this paper. One is the application of the model predictive control to the planar parallel manipulator, and the other one is to overcome the effects of the uncertainties of the DC motors and the performance of the position control due to the dynamic behavior of the manipulator.

scholarly journals Robust Position Control of an Over-actuated Underwater Vehicle under Model Uncertainties and Ocean Current Effects Using Dynamic Sliding Mode Surface and Optimal Allocation Control

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 747
Author(s):  
Mai The Vu ◽  
Tat-Hien Le ◽  
Ha Le Nhu Ngoc Thanh ◽  
Tuan-Tu Huynh ◽  
Mien Van ◽  
...  
Keyword(s):  
Control System ◽  
Motion Control ◽  
Optimal Allocation ◽  
Position Control ◽  
Sliding Mode ◽  
Underwater Vehicle ◽  
Ocean Current ◽  
Model Uncertainties ◽  
Control Module ◽  
Dynamic Sliding Mode

Underwater vehicles (UVs) are subjected to various environmental disturbances due to ocean currents, propulsion systems, and un-modeled disturbances. In practice, it is very challenging to design a control system to maintain UVs stayed at the desired static position permanently under these conditions. Therefore, in this study, a nonlinear dynamics and robust positioning control of the over-actuated autonomous underwater vehicle (AUV) under the effects of ocean current and model uncertainties are presented. First, a motion equation of the over-actuated AUV under the effects of ocean current disturbances is established, and a trajectory generation of the over-actuated AUV heading angle is constructed based on the line of sight (LOS) algorithm. Second, a dynamic positioning (DP) control system based on motion control and an allocation control is proposed. For this, motion control of the over-actuated AUV based on the dynamic sliding mode control (DSMC) theory is adopted to improve the system robustness under the effects of the ocean current and model uncertainties. In addition, the stability of the system is proved based on Lyapunov criteria. Then, using the generalized forces generated from the motion control module, two different methods for optimal allocation control module: the least square (LS) method and quadratic programming (QP) method are developed to distribute a proper thrust to each thruster of the over-actuated AUV. Simulation studies are conducted to examine the effectiveness and robustness of the proposed DP controller. The results show that the proposed DP controller using the QP algorithm provides higher stability with smaller steady-state error and stronger robustness.

Stiffness analysis of a planar parallel manipulator with variable platforms

2021 ◽  
pp. 1-18
Author(s):  
Xiaoyong Wu ◽  
Yujin Wang ◽  
Zhaowei Xiang ◽  
Ran Yan ◽  
Rulong Tan ◽  
...  
Keyword(s):  
Parallel Manipulator ◽  
Stiffness Analysis ◽  
Planar Parallel Manipulator

Kinematics of a New High-Precision Three-Degree-of-Freedom Parallel Manipulator

2006 ◽  
Vol 129 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Farhad Tahmasebi
Keyword(s):  
Power Dissipation ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degree Of Freedom ◽  
Base Plane ◽  
Degree Polynomial ◽  
Payload Capacity ◽  
Half Angle ◽  
Three Degree Of Freedom ◽  
Direct Kinematics

Closed-form direct and inverse kinematics of a new three-degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three-DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base mounted, higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of the tangent of the half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.

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