http://yetl.yabesh.ir/yetl1/handle/yetl/19040 Mon, 27 Apr 2026 10:59:55 GMT 2026-04-27T10:59:55Z http://localhost:80/yetl1/bitstream/id/184276/ http://yetl.yabesh.ir/yetl1/handle/yetl/19040 http://yetl.yabesh.ir/yetl1/handle/yetl/4311000 An Improved Dual Quaternion Dynamic Movement Primitives-Based Algorithm for Robot-Agnostic Learning and Execution of Throwing Tasks Liendo, Freddy; Hernández, Camilo; Galez, Christine Inspired by human nature, roboticists have conceived robots as tools meant to be flexible, capable of performing a wide variety of tasks. Learning from demonstration methods allow us to “teach” robots the way we would perform tasks, in a versatile and adaptive manner. Dynamic movement primitives (DMP) aims for learning complex behaviors in such a way, representing tasks as stable, well-understood dynamical systems. By modeling movements over the SE(3) group, modeled primitives can be generalized for any robotic manipulator capable of full end-effector 3D movement. In this article, we present a robot-agnostic formulation of discrete DMP based on the dual quaternion algebra, oriented to modeling throwing movements. We consider adapted initial and final poses and velocities, all computed from a projectile kinematic model and from the goal at which the projectile is aimed. Experimental demonstrations are carried out in both a simulated and a real environment. Results support the effectiveness of the improved method formulation. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4311000 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310996 Design and Modeling of an Expandable Bending Actuator With Multiple Pneumatic Sources Jing, Xishuang; Zhang, Zhenyu; Zeng, Bo; Zhao, Zhe; Hao, Jiakang; Chen, Siyu; Zhang, Chengyang This article describes the design and modeling of an expandable and inflatable bending actuator with multiple pneumatic sources. The actuator includes independent pneumatic modules sewn onto a flexible, nonstretch fabric structure. The bladders of the actuator consist of the maintaining layer with constant pressure and the driving layer with adjustable pressure. The active state of the actuator can be altered by adjusting the pressure of the driving layer while varying the number of driving layers can lead to different operational modes. Compared to other soft actuators, the proposed pneumatic actuator can achieve a favorable balance between high unit mass output torque and better response performance. Based on the geometrical constraints, we propose a mathematical model for our design to forecast the output torque and confirm its validity through experimentation. Finally, we examine the impact of modifying the actuator air supply mode on both the functionality and operational state of the actuator and test its dynamic performance. Additionally, it should be mentioned that the output torque performance of the actuator remains stable, with no significant changes observed undergoing more than 500 inflation and deflation cycles. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310996 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310993 A Conformal Geometric Algebra Method for Inverse Kinematics Analysis of 6R Robotic Arm Zhu, Dongyang; Zhang, Zhonghai; Li, Duanling Addressing the issue of angle multiplicity in solving joint angles using cosine expressions within the context of conformal geometric algebra for inverse kinematics analysis, an extended method for joint angle determination has been developed. The core of this method lies in the precise definition of the rotation plane for each joint and its corresponding rotation vector. By accurately calculating the angle between these two vectors and introducing a sign function as a coefficient, the correct sign for each joint angle is ensured, thereby determining the unique and correct value of the joint angle. Based on this foundation, we applied this improved joint angle solution method to the inverse kinematics analysis framework of conformal geometric algebra. To verify the effectiveness and accuracy of this method, we conducted detailed case studies using a 6R robotic arm with three orthogonally oriented axes and another with three parallel axes. The results showed that for the positional inverse solution of the three-axis orthogonal robotic arm, all eight possible solutions were successfully obtained; for the positional inverse solution of the three-axis parallel robotic arm, all four possible solutions were found. Furthermore, compared to the traditional Denavit–Hartenberg (D–H) parameter method, the conformal geometric algebra approach exhibits significant advantages in complex mechanisms. Especially when performing inverse kinematics analysis for three-axis parallel robotic arms, the conformal geometric algebra method achieves operational efficiency that is more than double that of the D–H parameter method, fully demonstrating its remarkable superiority in high-performance computing. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310993 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310991 Dynamic Manipulability for a Two-Link Manipulator Driven By Pneumatic Artificial Muscles and Passive Springs Maurya, Sushant; Dutta, Ashish In the case of manipulators actuated by unidirectional pneumatic artificial muscles (PAMs) and passive restoring springs, the system parameters and spring stiffness affect the reachable workspace and the dynamic manipulability. A two-link planar manipulator actuated by PAMs and passive springs was designed and fabricated to analyze the limitations of its dynamic manipulability. Kinematic analysis and forward dynamics simulations show the influence of parameters of passive springs, such as spring stiffness and spring prestretch, on workspace and trajectory tracking performance. Simulation results prove the limitations on the dynamic motion ability of a manipulator with passive springs in certain regions of its workspace as compared to that of bidirectional actuated manipulators. These motion limitations cannot be improved by optimizing the controller. Experimental results show the trajectory tracking performance similar to those obtained in the simulations, thus validating the simulations and the dynamic manipulability analysis. Consequently, we propose a task-based optimization formulation for determining the system parameters, such as stiffness and prestretch of passive springs, to track a given trajectory accurately. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310991 2025-01-01T00:00:00Z