Human–Robot Collaboration (HRC) is an interdisciplinary research area that has gained attention within the smart manufacturing context. To address changes within manufacturing processes, HRC seeks to combine the impressive physical capabilities of robots with the cognitive abilities of humans to design tasks with high efficiency, repeatability, and adaptability. During the implementation of an HRC cell, a key activity is the robot programming that takes into account not only the robot restrictions and the working space, but also human interactions. One of the most promising techniques is the so-called Learning from Demonstration (LfD), this approach is based on a collection of learning algorithms, inspired by how humans imitate behaviors to learn and acquire new skills. In this way, the programming task could be simplified and provided by the shop floor operator. The aim of this work is to present a survey of this programming technique, with emphasis on collaborative scenarios rather than just an isolated task. The literature was classified and analyzed based on: the main algorithms employed for Skill/Task learning, and the human level of participation during the whole LfD process. Our analysis shows that human intervention has been poorly explored, and its implications have not been carefully considered. Among the different methods of data acquisition, the prevalent method is physical guidance. Regarding data modeling, techniques such as Dynamic Movement Primitives and Semantic Learning were the preferred methods for low-level and high-level task solving, respectively. This paper aims to provide guidance and insights for researchers looking for an introduction to LfD programming methods in collaborative robotics context and identify research opportunities.

Human–robot collaboration (HRC) can be defined as the close interaction between a human user and a robot working together to accomplish a specific task. True collaboration, however, can only be realized when humans and robots can share the same workspace simultaneously and move freely within it. To address these problems, Learning from Demonstrations (LfD) helps robots become competent in solving plenty of complicated tasks, greatly reducing programming times and allowing task generalization. However, complex robot tasks require complex path planning modeling for a robot to move from one place to another in a heavily constrained workspace following a collision-free path. To this end, a robot programming framework based on Dynamic Movement Primitives (DMPs) is proposed. The framework derives and implements a solution for robot path planning and includes a new DMP formulation with volumetric obstacle avoidance for robot LfD. The formulation equips robotic systems with the capability of online adaptation in the presence of dynamic obstacles. Quantitative evaluations demonstrate high success rates (>96% in tested scenarios) in collision avoidance and typical trajectory adaptation times in the order of milliseconds (<5 ms), supporting its applicability. These methods have been applied in both simulation and real robotic scenarios using a UR10e collaborative robot from Universal Robots for testing and validation purposes. The results indicate that the proposed approach can effectively make the robot follow a user-defined trajectory and learn how to adapt it to avoid collisions with volumetric obstacles of different shapes and poses in an unconstrained human–robot collaborative environment.