Control Strategy and Trajectory Planning for Reconfiguration of a vA Based Metamorphic Parallel Manipulator

2013 ◽  
Author(s):  
Evangelos Emmanouil ◽  
Ketao Zhang ◽  
Jian S. Dai
Keyword(s):  
Phase Change ◽  
Trajectory Planning ◽  
Control Strategy ◽  
Parallel Manipulator ◽  
Redundant Actuation ◽  
Planning Algorithm ◽  
Source Phase

Mechanisms with reconfigurability have become a trend in development of multi-functional robots which can adapt to unexpected environments and perform complicated tasks. This paper presents a novel metamorphic parallel manipulator with the ability to change its mobility through the phase change of a variable-axis (vA) joint integrated in each limb. The platform has 6 DOFs in the source phase and can reconfigure its mobility to 5, 4 and 3 resorting to redundant actuation. This leads to reconfigurability and multi-functionality of the parallel manipulator characterized by the mobility configuration variation. A control strategy and a trajectory planning algorithm for reconfiguring the mobility configuration of the manipulator are proposed and simulations are carried out to identify a proper way of reconfiguration.

Synchronization Control of Planar 2-Dof Robot with Redundant Actuation

2012 ◽  
Vol 468-471 ◽  
pp. 1414-1420 ◽  
Author(s):  
Jian Wei Mi ◽  
Hong Bao ◽  
Jing Li Du
Keyword(s):  
Control Strategy ◽  
Parallel Manipulator ◽  
Synchronization Control ◽  
Redundant Actuation ◽  
Model Errors ◽  
Position Measurement ◽  
Coupling Relationship ◽  
The Stability ◽  
Coupling Error ◽  
Synchronization Performance

Considering the special characteristics of the redundant parallel manipulator, with emphasis on the variable of structure, relatively small workspace and the strong coupling relationship among arms，a synchronization control strategy is presented in this paper. Since in the feedforward ,the inertial and the coriolis matrix are designed constant according to relatively small workspace, position measurement of the endeffector in plane is ignored. Synchronization error and coupling error are introduced to reject the model errors of inertial and coriolis matrix as stated above. Using the method, the errors of driving arms may be reduced, as well as synchronization performance among axes improves. The stability of the controllers was proved by Lyapunov. Finally, experimental results show the feasibility.

Cubic Polynomial Trajectory Planning Algorithm Based on Ideal Drive Force for Aircraft Fusagle Automatic Position and Pose Adjustment

2013 ◽  
Vol 655-657 ◽  
pp. 1691-1696
Author(s):  
Yong Guo Zhu ◽  
Xiang Huang ◽  
Guo Hua Qing
Keyword(s):  
Trajectory Planning ◽  
Driving Forces ◽  
Optimal Algorithm ◽  
Least Square ◽  
Redundant Actuation ◽  
Minimal Norm ◽  
Automatic Adjustment ◽  
Drive Force ◽  
Planning Algorithm ◽  
Cubic Polynomial

In order to ensure the stationarity of the aircraft fusagle automatic adjustment and reduce the fluctuation of the drive force, the redundant actuation optimal algorithm is presented in this paper. Firstly, using Newton-Euler method, the dynamics equations of pose adjustment system are established. Based on the equations, the driving forces can be sovled. Secondly, according to the constraint conditions and pose adjustement process, Cubic Polynomial trajectory planning algorithm is proposed for the aircraft fusagle automatic adjustment. Thirdly, in order to reduce the fluctuation of the drive force, the redundant actuation optimal algorithm is presented. Simulation results show that the presented trajectory planning algorithm has good dynamic characteristics and satisfies engineering requirements. Moreover, the differences between the solutions of optimal algorithm and ideal drive forces are much less than the differences between the minimal norm least square solution and ideal drive forces.

Trajectory Planning of Wire-Driven Parallel Manipulator Based on Influence Coefficient Method

2010 ◽  
Vol 143-144 ◽  
pp. 313-317
Author(s):  
Yi Cao ◽  
Xuan Yao Wang ◽  
Hui Zhou ◽  
Shen Long ◽  
Meng Si Liu
Keyword(s):  
Trajectory Planning ◽  
Parallel Manipulator ◽  
Angular Acceleration ◽  
Influence Coefficient ◽  
Influence Coefficient Method ◽  
Planning Algorithm ◽  
Moving Platform ◽  
Orientation Parameters ◽  
Orientation Workspace ◽  
Coefficient Method

The dynamic model of a 6-DOF wire-driven parallel manipulator is established, based on influence coefficient method for wire-driven parallel manipulator trajectory planning algorithm is proposed, the orientation parameters by Euler angles of moving platform of time first-order and second-order derivative which is not a moving platform angular velocity and angular acceleration is verified. For the moving platform position and orientation workspace trajectory planning, the kinematic characteristics of wires are discussed. The simulation results show that the tension of the wires are always greater than 0, the expressions of velocity, acceleration and tension of wires are exceptionally clear and simple. Also, the method of trajectory planning proposed is suitable for general 6-DOF wire-driven parallel manipulator.

Minimum-Jerk Trajectory Planning of a 3-DOF Translational Parallel Manipulator

2015 ◽  
Author(s):  
Song Lu ◽  
Yangmin Li
Keyword(s):  
Trajectory Planning ◽  
Parallel Manipulator ◽  
Optimization Problem ◽  
Fixed Time ◽  
Minimax Optimization ◽  
Time Duration ◽  
Minimum Jerk ◽  
Kinematic Inversion ◽  
Planning Algorithm ◽  
Improving Accuracy

Since jerk-limiting is universally recognized to possess the advantages of reducing residual vibration and improving accuracy, this paper utilizes a minimum-jerk trajectory planning algorithm in trajectory planning of a three degree-of-freedom 3-Prismatic-Universal-Universal (3PUU) translational parallel manipulator. The trajectory execution time is set to fixed time duration. The sequence of joint positions are derived by a series of predefined via-points in Cartesian space through kinematic inversion. In order to generate a trajectory featuring great continuity and fine smoothness, a piecewise fifth-order polynomial is used to interpolate the joint position series and generate a smooth trajectory characterized by continuous velocity, acceleration, and jerk. The minimum jerk trajectory planning algorithm, which minimizes the maximum of the absolute value of joints’ jerk, is actually a constrained minimax optimization problem. Subjecting to the specified limitations of kinematic constraints, this multi-variables constrained optimization problem is solved by the sequential quadratic programming (SQP) strategy. The simulated results demonstrate that this trajectory planning algorithm for the designed parallel manipulator is effective and feasible.

scholarly journals Control system of 4-DOF palletizing robot based on improved R control multi-objective trajectory planning

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110027
Author(s):  
Jianqiang Wang ◽  
Yanmin Zhang ◽  
Xintong Liu
Keyword(s):  
Control System ◽  
Trajectory Planning ◽  
Robot Control ◽  
Machining Process ◽  
Planning System ◽  
Positioning Accuracy ◽  
Multi Objective ◽  
Planning Algorithm ◽  
Function Testing ◽  
Robot Control System

To realize efficient palletizing robot trajectory planning and ensure ultimate robot control system universality and extensibility, the B-spline trajectory planning algorithm is used to establish a palletizing robot control system and the system is tested and analyzed. Simultaneously, to improve trajectory planning speeds, R control trajectory planning is used. Through improved algorithm design, a trajectory interpolation algorithm is established. The robot control system is based on R-dominated multi-objective trajectory planning. System stack function testing and system accuracy testing are conducted in a production environment. During palletizing function testing, the system’s single-step code packet time is stable at approximately 5.8 s and the average evolutionary algebra for each layer ranges between 32.49 and 45.66, which can save trajectory planning time. During system accuracy testing, the palletizing robot system’s repeated positioning accuracy is tested. The repeated positioning accuracy error is currently 10−1 mm and is mainly caused by friction and the machining process. By studying the control system of a four-degrees-of-freedom (4-DOF) palletizing robot based on the trajectory planning algorithm, the design predictions and effects are realized, thus providing a reference for more efficient future palletizing robot design. Although the working process still has some shortcomings, the research has major practical significance.

Trajectory planning for coordinately operating robots

1990 ◽  
Vol 4 (3) ◽  
pp. 165-177 ◽  
Author(s):  
Y. P. Chien ◽  
Qing Xue
Keyword(s):  
Trajectory Planning ◽  
Three Dimensional ◽  
Initial Position ◽  
Minimum Time ◽  
Future Research ◽  
Rigid Object ◽  
Redundant Robots ◽  
Planning Algorithm ◽  
The Common ◽  
Joint Velocity

An efficient locally minimum-time trajectory planning algorithm for coordinately operating multiple robots is introduced. The task of the robots is to carry a common rigid object from an initial position to a final position along a given path in three-dimensional workspace in minimum time. The number of robots in the system is arbitrary. In the proposed algorithm, the desired motion of the common object carried by the robots is used as the key to planning of the trajectories of all the non-redundant robots involved. The search method is used in the trajectory planning. The planned robot trajectories satisfy the joint velocity, acceleration and torque constraints as well as the path constraints. The other constraints such as collision-free constraints, can be easily incorporated into the trajectory planning in future research.

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