An Improved Dual Quaternion Dynamic Movement Primitives-Based Algorithm for Robot-Agnostic Learning and Execution of Throwing Tasks
Abstract 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 […]
Chained Timoshenko Beam Constraint Model With Applications in Large Deflection Analysis of Compliant Mechanism
Abstract Accurately analyzing the large deformation behaviors of compliant mechanisms has always been a significant challenge in the design process. The classical Euler–Bernoulli beam theory serves as the primary theoretical basis for the large deformation analysis of compliant mechanisms. However, neglecting shear effects may reduce the accuracy of modeling compliant mechanisms. Inspired by the beam […]
Harnessing Biomechanical Energy Using Shoulder Exoskeleton: Electrical Energy Regeneration
Abstract Implementing back-drivable actuators with energy regeneration capabilities can improve the efficiency and extend the battery life of robotic exoskeletons, by converting a portion of dissipated energy during negative mechanical work into electrical energy. We present the first study of the regeneration capabilities of shoulder exoskeletons, which includes experimental motor parameter identification, the development of […]
Kinematic Modeling and Workspace Analysis of a Cable-Driven Parallel Robot Considering Environmental Collisions
Abstract Traditional cable-driven parallel robots (CDPRs) are limited by the collision-free constraints imposed by cables and environmental obstacles; however, motion planning cannot avoid all obstacles, limiting the CDPR’s workspace. This article presents a kinematic model for the CDPR that accounts for environmental collisions with straight lines, cylinders, and cuboids enabling the cables to keep operating […]
A Conformal Geometric Algebra Method for Inverse Kinematics Analysis of 6R Robotic Arm
Abstract 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 […]
Dynamic Manipulability for a Two-Link Manipulator Driven By Pneumatic Artificial Muscles and Passive Springs
Abstract 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 […]
Case Study and Preliminary Validation of a Parametric, Three-Dimensional Printable Tendon-Driven Biomimetic Hand Exoskeleton
Abstract Portable hand exoskeletons are reaching homes, providing daily assistance to people with hand impairments and enhancing their quality of life. Their design, however, is rarely based on the biomimetics of human finger kinematics, missing the benefits of anatomical tendon pulley-based actuation, such as natural and comfortable movement with efficient force transmission. We present a […]
Design and Control of a Piezo-Driven z – θ x – θ y Parallel Nanopositioning Stage With Two-Stage Rhombic Amplification Structure
Abstract In this article, a large-stroke compact of z-θx-θy piezoelectric nanopositioning stage and the corresponding control method are designed. A two-stage rhombic amplifying mechanism equipped with piezoelectric actuator (PZTA) is designed, which provides driving energy through flexible lamina deformation. A large-stroke compact piezoelectric nanopositioning stage is designed using four-corner arrangement. Based on the statics analysis, […]
Stiffness Evaluation of a Decoupled Cartesian Parallel Manipulator
Abstract This article proposes a new approach to evaluate the stiffness of a three degrees-of-freedom decoupled Cartesian parallel manipulator which uses revolute joints. Prior to the discussion on the new approach, the stiffness of an individual limb is discussed. This discussion focuses on the influence of kinematic parameters on the limb’s stiffness. Taking advantage of […]
Design and Modeling of an Expandable Bending Actuator With Multiple Pneumatic Sources
Abstract 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 […]
