Time Minimum Trajectory Planning of a 2-DOF Translational Parallel Robot for Pick-and-place Operations

CIRP Annals ◽  
2007 ◽  
Vol 56 (1) ◽  
pp. 365-368 ◽  
Author(s):  
T. Huang ◽  
P.F. Wang ◽  
J.P. Mei ◽  
X.M. Zhao ◽  
D.G. Chetwynd
Keyword(s):  
Trajectory Planning ◽  
Parallel Robot ◽  
Pick And Place

Dynamic Trajectory Planning for a Three Degrees-of-Freedom Cable-Driven Parallel Robot Using Quintic B-Splines

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Sen Qian ◽  
Kunlong Bao ◽  
Bin Zi ◽  
W. D. Zhu
Keyword(s):  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Planning Method ◽  
End Effector ◽  
B Spline ◽  
B Splines ◽  
Pick And Place ◽  
Two Factors ◽  
Three Degrees Of Freedom

Abstract This paper presents a new trajectory planning method based on the improved quintic B-splines curves for a three degrees-of-freedom (3-DOF) cable-driven parallel robot (CDPR). First, the conditions of positive cables’ tension are expressed in terms of the position and acceleration constraints of the end-effector. Then, an improved B-spline curve is introduced, which is employed for generating a pick-and-place path by interpolating a set of given via-points. Meanwhile, by expressing the position and acceleration of the end-effector in terms of the first and second derivatives of the improved B-spline, the cable tension constraints are described in the form of B-spline parameters. According to the properties of the defined pick-and-place path, the proposed motion profile is dominated by two factors: the time taken for the end-effector to pass through all the via-points and the ratio between the nodes of B-spline. The two factors are determined through multi-objective optimization based on the efficiency coefficient method. Finally, experimental results on a 3-DOF CDPR show that the improved B-spline exhibits overall superior behavior in terms of velocity, acceleration, and cables force compared with the traditional B-spline. The validity of the proposed trajectory planning method is proved through the experiments.

scholarly journals Trajectory-Planning and Normalized-Variable Control for Parallel Pick-and-Place Robots

2019 ◽  
Vol 11 (3) ◽  
Author(s):  
Peyman Karimi Eskandary ◽  
Bruno Belzile ◽  
Jorge Angeles
Keyword(s):  
Trajectory Planning ◽  
Cycle Time ◽  
Kinematic Chain ◽  
Linear Quadratic Regulator ◽  
Parallel Robot ◽  
Linear Quadratic ◽  
Trajectory Tracking Control ◽  
Moving Plate ◽  
Control Scheme ◽  
Pick And Place

Trajectory planning and an efficient control scheme play a crucial role in improving the performance of pick-and-place robots. This paper introduces a novel method of trajectory planning with cycle time and path constraints. Assuming that a smooth trajectory is given, to be followed within a prescribed cycle time, the newly proposed method of trajectory planning removes the torque peaks of the actuators by a suitable scheduling of the velocity of the moving plate. Since pick-and-place robots are usually expected to meet the end poses in a certain time span, while disregarding the intermediate poses, the velocity can be tuned properly around the critical points of the trajectory by means of a time-scaling function. Moreover, the authors report the formulation of a linear quadratic regulator (LQR) controller with normalized variables to be used in conjunction with our trajectory-tracking control scheme for an in-house-developed Schönflies-motion generator. This parallel robot offers a functionally symmetric, single-loop architecture, with an isostatic kinematic chain, and virtually unlimited rotatability of its gripper. A comparison between two actuation systems developed by the authors is conducted via simulation results.

scholarly journals Trajectory Planning and Optimization for a Par4 Parallel Robot Based on Energy Consumption

2019 ◽  
Vol 9 (13) ◽  
pp. 2770
Author(s):  
Xiaoqing Zhang ◽  
Zhengfeng Ming
Keyword(s):  
Energy Consumption ◽  
Trajectory Planning ◽  
Design Method ◽  
Mechanical Energy ◽  
Parallel Robot ◽  
Sixth Order ◽  
Function Parameter ◽  
Pick And Place ◽  
Order Polynomial ◽  
Fifth Order

A study on trajectory planning and optimization for a Par4 parallel robot was carried out, based on energy consumption in high-speed picking and placing. In the end-effector operating space of the Par4 parallel robot, the rectangular transition of the pick-and-place trajectory was rounded by a Lamé curve. A piecewise design method was adopted to accomplish trajectory shape planning for displacement, velocity and acceleration. To make the Par4 robot’s end run more smoothly and to reduce residual vibration, asymmetric fifth-order and sixth-order polynomial motion laws were employed. With the aim of reaching the minimum mechanical energy consumption for the Par4 parallel robot, the recently proposed Grey Wolf Optimizer (GWO) algorithm was adopted to optimize the planning trajectory. The validity of the design method was verified by experiments, and it was found that the minimum mechanical energy consumption of the optimal trajectory planned under the law of fifth-order polynomial motion is lower than that of sixth-order polynomial motion. In addition, the experiments also revealed the optimal values of Parameters e and f, which were the parameters of the Lamé curve function. Parameter e can be calculated as half the pick-up span for the minimum mechanical energy consumption, unlike parameter f, whose optimal value depends on specific circumstances such as the pick-and-place coordinates and the pick-up height.

scholarly journals Control Solution for a Cable-Driven Parallel Robot With Highly Variable Payload

2018 ◽  
Author(s):  
Etienne Picard ◽  
Stéphane Caro ◽  
Franck Plestan ◽  
Fabien Claveau
Keyword(s):  
Real Time ◽  
Parallel Robot ◽  
Pd Controller ◽  
Control Solution ◽  
Total Load ◽  
Heterogeneous Objects ◽  
Control Scheme ◽  
Pick And Place ◽  
Payload Mass ◽  
Moving Platform

This paper deals with the design of a robust control scheme for a suspended Cable-Driven Parallel Robot (CDPR), composed of eight cables and a moving platform (MP), suitable for pick-and-place operations of heterogeneous objects with different shapes, sizes and masses, up to a total load of 700 kg. Dynamometers measure the force applied by each cable onto the moving-platform and are used to assess the payload mass at any time. In the proposed control solution, each motor of the CDPR is directly driven by a PD torque controller, which takes benefit of the real-time payload estimation in a feedforward term. In order to evaluate its performance, experiments on a typical pick and place trajectory are realized for different payloads. As a result, three control schemes: (i) a Proportional-Derivative (PD) torque controller; (ii) a PD controller with compensation of the MP mass only and (iii) a PD controller with real-time mass estimation and compensation are experimentally compared with respect to their positioning accuracy. It turns out that a good estimation of the payload is obtained in real-time thanks to the dynamometers. Moreover, the higher the payload mass, the more accurate the proposed controller with respect to its two counterparts.

Delta Parallel Robot Based on Crank-Slider Mechanism

2017 ◽  
Vol 6 (2) ◽  
pp. 112
Author(s):  
Zhe Qin ◽  
Xiao-Chu Liu ◽  
Zhuan Zhao
Keyword(s):  
Parallel Robot ◽  
Force Transmission ◽  
Practical Application ◽  
Cartesian Space ◽  
Output Torque ◽  
Performance Indexes ◽  
Pick And Place ◽  
Delta Robot ◽  
Three Degree Of Freedom ◽  
Pick And Place Operation

A three-degree-of-freedom Delta parallel manipulator driven by a crank-slider mechanism is proposed. In Cartesian space, a gate-shaped curve is taken as the path of the pick-and-place operation, combining with the inverse kinematics theory of the Delta robot, and a mathematical model of robot statia force transmission is established. The force and the output torque of the robot-driven joint are taken as the main performance indexes, and the value of the crank-slider mechanism applied to Delta robot is further measured. The simulation results show that the delta robot driven by the crank slider mechanism can reduce the force and output torque of the driving joint during the picking and discharging operation, and has good practical application value.

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