Dynamic Transition Trajectory Planning of Three-DOF Cable-Suspended Parallel Robots

2017 ◽  
pp. 231-242 ◽  
Author(s):  
Xiaoling Jiang ◽  
Clément Gosselin
Keyword(s):  
Trajectory Planning ◽  
Parallel Robots ◽  
Dynamic Transition ◽  
Transition Trajectory

Dynamic Point-to-Point Trajectory Planning Beyond the Static Workspace for Six-DOF Cable-Suspended Parallel Robots

2018 ◽  
Vol 34 (3) ◽  
pp. 781-793 ◽  
Author(s):  
Xiaoling Jiang ◽  
Eric Barnett ◽  
Clement Gosselin
Keyword(s):  
Trajectory Planning ◽  
Parallel Robots ◽  
Six Dof ◽  
Point To Point

Dynamic Point-To-Point Trajectory Planning for Three Degrees-of-Freedom Cable-Suspended Parallel Robots Using Rapidly Exploring Random Tree Search

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Sheng Xiang ◽  
Haibo Gao ◽  
Zhen Liu ◽  
Clément Gosselin
Keyword(s):  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Parallel Robots ◽  
Tree Search ◽  
Planning Techniques ◽  
Motion Primitive ◽  
Planning Technique ◽  
Point To Point ◽  
Three Degrees Of Freedom ◽  
Specific Distance

Abstract This paper proposes a dynamic point-to-point trajectory planning technique for three degrees-of-freedom (DOFs) cable-suspended parallel robots. The proposed technique is capable of generating feasible multiple-swing trajectories that reach points beyond the footprint of the robot. Tree search algorithms are used to automatically determine a sequence of intermediate points to enhance the versatility of the planning technique. To increase the efficiency of the tree search, a one-swing motion primitive and a steering motion primitive are designed based on the dynamic model of the robot. Closed-form expressions for the motion primitives are given, and a corresponding rapid feasibility check process is proposed. An energy-based metric is used to estimate the distance in the Cartesian space between two points of a dynamic point-to-point task, and this system’s specific distance metric speeds up the coverage. The proposed technique is evaluated using a series of Monte Carlo runs, and comparative statistics results are given. Several example trajectories are presented to illustrate the approach. The results are compared with those obtained with the existing state-of-the-art methods, and the proposed technique is shown to be more general compared to previous analytical planning techniques while generating smoother trajectories than traditional rapidly exploring randomized tree (RRT) methods.

Time-Optimal Trajectory Planning of Cable-Driven Parallel Mechanisms for Fully Specified Paths With G1-Discontinuities

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Eric Barnett ◽  
Clément Gosselin
Keyword(s):  
Trajectory Planning ◽  
Optimal Trajectory ◽  
Trajectory Generation ◽  
Optimal Solution ◽  
Test System ◽  
Parallel Robots ◽  
Parallel Mechanisms ◽  
Cable Tension ◽  
Time Optimal ◽  
Optimal Trajectory Planning

Time-optimal trajectory planning (TOTP) is a well-studied problem in robotics and manufacturing, which involves the minimization of the time required for the operation point of a mechanism to follow a path, subject to a set of constraints. A TOTP technique, designed for fully specified paths that include abrupt changes in direction, was previously introduced by the first author of this paper: an incremental approach called minimum-time trajectory shaping (MTTS) was used. In the current paper, MTTS is converted to a dynamic technique and adapted for use with cable-driven parallel robots, which exhibit cable tension and motor torque constraints. For many applications, cable tensions along a path are verified after trajectory generation, rather than imposed during trajectory generation. For the technique proposed in this paper, the cable-tension constraints are imposed directly and fully integrated with MTTS, during trajectory generation, thus maintaining a time-optimal solution. MTTS is applied to a test system and path, and compared to the bang–bang technique. With the same constraints, the results obtained with both techniques are found to be very close. However, MTTS can be applied to a wider variety of paths, and accepts constraints on jerk and total acceleration that would be difficult to apply using the bang–bang approach.

Time-Optimal Trajectory Planning of Cable-Driven Parallel Mechanisms for Fully-Specified Paths With G1 Discontinuities

2013 ◽  
Author(s):  
Eric Barnett ◽  
Clément Gosselin
Keyword(s):  
Trajectory Planning ◽  
Optimal Trajectory ◽  
Trajectory Generation ◽  
Optimal Solution ◽  
Vertical Direction ◽  
Parallel Robots ◽  
Parallel Mechanisms ◽  
Time Optimal ◽  
Time Required ◽  
Optimal Trajectory Planning

Time-optimal trajectory planning (TOTP) is a well-studied problem in robotics and manufacturing, which involves the minimization of the time required for the operation point of a mechanism to follow a path, subject to a set of constraints. A TOTP technique, designed for fully-specified paths that include abrupt changes in direction, was previously introduced by the first author of this paper: an incremental approach called minimum-time trajectory shaping (MTTS) was used. In the current paper, MTTS is adapted for use with cable-driven parallel robots, which exhibit the additional constraint that all cable tensions remain positive along a path to be followed. For many applications, cable tensions along a path are verified after trajectory generation, rather than imposed during trajectory generation. For the technique proposed in this paper, the minimum-tension constraint is imposed directly and is fully integrated with MTTS, during trajectory generation, thus maintaining a time-optimal solution. This approach is relevant for cable-driven mechanism applications that involve high accelerations, particularly in the vertical direction.

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