Collaborative Robotics Applications Research Articles

Safety Assessment of Collaborative Robotics Through Automated Formal Verification

A crucial aspect of physical human–robot collaboration (HRC) is to maintain a safe common workspace for human operator. However, close proximity between human–robot and unpredictability of human behavior raises serious challenges in terms of safety. This article proposes a risk analysis methodology for collaborative robotic applications, which is compatible with well-known standards in the area and relies on formal verification techniques to automate the traditional risk analysis methods. In particular, the methodology relies on temporal logic-based models to describe the different possible ways in which tasks can be carried out, and on fully automated formal verification techniques to explore the corresponding state space to detect and modify the hazardous situations at early stages of system design.

Dynamic speed and separation monitoring for collaborative robot applications – Concepts and performance

Abstract Speed and separation monitoring (SSM) allows safeguarding the operator in collaborative robot applications by maintaining a certain minimum separation distance during operation. A continuous adaptation of the robot velocity in response to relative operator and robot motion can be employed to improve the efficiency of SSM-type applications. The present paper presents two approaches for obtaining a robot velocity limit for this adaptation, considering the separation distance as well as the direction of robot motion. Using a collaborative machine tending task as an example, the impact of these approaches on application productivity was assessed in physical trials and compared to that of conventional safeguarding methods, i.e. zone-based supervision and safeguarding by physical barriers. The trials confirmed that the continuous speed adaptation has a notable productivity benefit over the state of industrial practice. Major factors that influence the particular benefit, such as the frequency and timing of operator presence near the robot, have been identified and investigated. Before these concepts can be applied in industry, machinery safety requirements must be satisfied; at present, this depends particularly on the availability of sufficiently reliable information on the human position, which is not provided by safety sensors today.

Formal model of human erroneous behavior for safety analysis in collaborative robotics

Abstract Recent developments in manufacturing technologies, also known as Industry 4.0, seek to build Smart Factories where supply chains and production lines are equipped with a higher level of automation. However, this significant innovation does not entirely eliminate the need for the presence of human operators; on the contrary, it requires them to collaborate with robots and execute hybrid tasks. Thus, creating safe workspaces for human operators is crucial for the future of factories where humans and robots collaborate closely in common workspaces. The uncertainty of human behavior and, consequently, of the actual execution of workflows, pose significant challenges to the safety of collaborative applications. This paper extends our earlier work, a formal verification methodology to analyze the safety of collaborative robotics applications (Askarpour et al. 2017) [1], with a rich non-deterministic formal model of operator behaviors that captures the hazardous situations resulting from human errors. The model allows safety engineers to refine their designs until all plausible erroneous behaviors are considered and mitigated. The solidity of the proposed approach is evaluated on a pair of real-life case studies.

An application of collaborative robots in a food production facility

Despite the food industry being a leading sector of the European economy, the level of penetration of automation is still low. The main reasons lie on the small margin of food items which does not encourage technological investments, the extremely spread vendors market i.e. mostly small and medium enterprises, and the high level of flexibility and care required to handle food products along production, packaging, and storage operations. Nevertheless, the advent of collaborative, small and flexible robots provides great opportunities for the design and development of new effective processes integrating the human flexibility with the efficiency of automation.This paper explores the impact of adopting collaborative robots in the food catering industry, by illustrating a case study developed for the end-of-line of a catering production system. A generalizable methodology is proposed to support the study of the technical and economic feasibility of the implementation of such technology.This methodology is intended to support managers of the food industry to analyse the constraints that limit the automation of a process and to measure the expected performance of the system in terms of throughput, ergonomics and economic benefits resulting from the adoption of collaborative robots.

Collaborative robots in assembly: A practical approach for tasks distribution

The challenge of tasks allocation between human and robot is a known problem for industrial application of collaborative robots in assembly. This paper aims to describe a framework for a dynamic task distribution based on physical properties of the components, tasks characterization and collaborative workspace. The developed tasks-distribution is achieved through a set of assembly attributes with various scores for contrasting cycle times, adaptability and safety. The work is demonstrated with an industrial case of human-robot collaborative assembly process.

Sleeved Bending Actuators for Soft Grippers: A Durable Solution for High Force-to-Weight Applications

Soft grippers are known for their ability to interact with objects that are fragile, soft or of an unknown shape, as well as humans in collaborative robotics applications. However, state-of-the-art soft grippers lack either payload capacity or durability, which limits their use in industrial applications. In fact, high force density pneumatic soft grippers require high strain and operating pressure, both of which impair their durability. This work presents a new sleeved bending actuator for soft grippers that is capable of high force density and durability. The proposed actuator is based on design principles previously proven to improve the life of pneumatic artificial muscles, where a sleeve provides a uniform reinforcement that reduces local stresses and strains in the inflated membrane. The sleeved bending actuator features a silicone membrane and an external two-material sleeve that can support high pressures while providing a flexible grip. The proposed sleeved bending actuators are validated through two grippers, sized according to foreseen soft gripper applications: A small gripper for drone perching and lightweight food manipulation, and a larger one for the manipulation of heavy material (>5 kg) of various weights and sizes. Performance assessment shows that these grippers have payloads up to 5.2 kg and 20 kg, respectively. Durability testing of the grippers demonstrates that the grippers have an expected lifetime ranging from 263,000 cycles to more than 700,000 cycles. The grippers are tested in various settings, including the integration of a gripper into a Phantom 2 quadcopter, a perching demonstration, as well as the gripping of light and heavy food items. Experiments show that sleeved bending actuators constitute a promising avenue for durable and strong soft grippers.

Stretchable, Flexible, Scalable Smart Skin Sensors for Robotic Position and Force Estimation.

The design and validation of a continuously stretchable and flexible skin sensor for collaborative robotic applications is outlined. The skin consists of a PDMS skin doped with Carbon Nanotubes and the addition of conductive fabric, connected by only five wires to a simple microcontroller. The accuracy is characterized in position as well as force, and the skin is also tested under uniaxial stretch. There are also two examples of practical implementations in collaborative robotic applications. The stationary position estimate has an RMSE of mm, and the sensor error stays within mm even under stretch. The skin consistently provides an emergency stop command at only N of force and is shown to maintain a collaboration force of 10 N in a collaborative control experiment.

A flexible system for gesture based human-robot interaction

In industrial collaborative robotics, operators and robots perform complex tasks working together without physical barriers. Under this premise, the availability of a flexible, robust and fast interaction system between the robot and the workers is a necessity.Human beings use voice and gestures to achieve a natural interaction. Taking into account the environmental conditions usually present in workshops with noise and poor lighting conditions, combining both communication channels can contribute to make the interaction more robust.This research work presents a solution to define, setup and run a flexible and robust gesture interaction system to integrate in collaborative robotics applications.

Collision Avoidance Algorithm for Collaborative Robotics

The paper discusses a study on a real-time collision avoidance algorithm for collaborative robotics applications. Within the work it is considered that a vision system detects the position of an obstacle and defines an ellipsoid which completely includes it. A similar virtual ellipsoid is considered to include the end effector, and its pose is computed based on the robot configuration. The distance between ellipsoids is input into the collision avoidance algorithm based on the method of artificial potentials. The tuning of the algorithm is described herein, along with an analysis of its performance under different operating conditions. The results of two collision avoidance tests are also presented. For the first test, the end-effector must avoid a fixed obstacle placed along a planned path. For the second test, the obstacle is moving, following a trajectory that intersects that of the end-effector. Finally, the behavior of the algorithm with increasing velocities of the end-effector and obstacle is analyzed.

Movement Characteristics Analysis and Dynamic Simulation of Collaborative Measuring Robot

Human-machine collaboration is becoming increasingly more necessary, and so collaborative robot applications are also in high demand. We selected a UR10 robot as our research subject for this study. First, we applied D-H coordinate transformation of the robot to establish a link system, and we then used inverse transformation to solve the robot’s inverse kinematics and find all the joints. Use Lagrange method to analysis UR robot dynamics; use ADAMS multibody dynamics simulation software to dynamic simulation; verifying the correctness of the derived kinetic models.

A computationally efficient safety assessment for collaborative robotics applications

Safety during interaction with unstructured and dynamic environments is now a well established requirement for complex robotic systems. A wide variety of approaches focus on the introduction of safety evaluation methods in order to shape a consequent safety-oriented control strategy, able to reactively prevent collisions between the robot and potential obstacles, including a human being. This paper presents a new safety assessment, named kinetostatic safety field, that captures the risk in the vicinity of an arbitrary rigid body “source of danger” (e.g. an obstacle, a human body part or a robot link) moving in R3. The safety field depends on the position and velocity of the body but it is also influenced by its real shape and size, exploiting its triangular mesh. The introduction of a body-fixed reference frame in the definition of the field provides closed form computability and an effective computation time reduction, that allows for real-time applications. In particular, intensive computations, connected to the specific body geometry, can be performed only once and off-line, ensuring a fast and constant on-line computation time, independently of the number of mesh elements. Furthermore, we combine the safety field concept with a safety-oriented reactive control strategy for redundant manipulators. Our approach allows to enhance safety in several real-time collision avoidance scenarios, including collision avoidance with potential obstacles, self-collision avoidance and safe human–robot coexistence. The proposed control strategy is validated through experiments performed on an ABB FRIDA dual arm robot.

Embedded solutions for a class of highly unstable, underactuated and self-balancing robotic systems

This paper presents a didactic framework in embedded electronics systems that is used to elicit awareness into students and engineers on the design issues arising in the realization of a class of underactuated robots and aerial vehicles that needs be robustly controlled due to their intrinsic unstability. The applications prototyped on the embedded platform presented here are conceived, by design, to be compliant with tiny collaborative robotics applications in order to adhere to the needs of the complex cyber-physical systems problem. The proposed platform is self-contained with on-board sensing and computation. Its engineering uses only off-the-shelf and mass production components. The system is based on a general purpose embedded board equipped with a 32-bit microcontroller which is able to manage all the basic tasks of this robotic platform: sensing, actuation, control and communication. The framework is described, and initial experimental results are introduced. Three applications are presented in this work as a validation of the methodology: a ballbot robot, a legged robot and a quadrotor aerial vehicle. The chosen case studies are robotics applications that are specialized in performing maneuvers when operating in tight spaces as in the human living environments.

The Pransky interview: Dr Esben Ostergaard, inventor, co-founder and CTO of Universal Robots

Purpose – This paper, a “Q&A interview” conducted by Joanne Pransky of Industrial Robot Journal, aims to impart the combined technological, business and personal experience of a prominent, robotic industry engineer-turned entrepreneur regarding the evolution, commercialization and challenges of bringing a technological invention to market. Design/methodology/approach – The interviewee is Dr Esben H. Ostergaard, inventor, co-founder and chief technology officer of Universal Robots. From building his first robot to solve a local industrial problem at the age of four, to building the world’s first collaborative robot company, Dr Ostergaard shares his lifelong ventures as a robot scientist, inventor and entrepreneur. Findings – Dr Ostergaard received degrees in computer science, physics and multimedia at Aarhus University in Denmark, and a PhD in robotics from the University of Southern Denmark. While at Aarhus, Dr Ostergaard pursued his hobby of robot football, and in 1998, his team STATIC became the world champion of the Federation of International Robot-soccer Association (FIRA). Dr Ostergaard held research positions at the University of Southern California (USC) Robotics Labs and at the Advanced Industrial Science and Technology (AIST) in Tsukuba/Tokyo. During the years 2001-2005 as a researcher and assistant professor in robotics and user interfaces at University of Southern Denmark, he created the foundation for a reinvention of the industrial robot. This led him to found Universal Robots in 2005 with two of his research colleagues. Originality/value – From a young child who played with LEGOs until he got a Commodore 64, Dr Ostergaard has always been interested in robotics. His unique multidisciplinary education and multicultural research experiences helped him to pioneer a new multi-axis, lightweight industrial robot and launch the successful company, Universal Robots, which has grown from its three co-founders to nearly 150 employees, with more than 4,000 collaborative robot applications installed in over 50 countries worldwide. Dr Ostergaard has over 30 patents and has received many awards, including the 2012 IEEE-IFR Invention and Entrepreneurship Award (IERA), the 2013 Japanese Institute Good Design Award, the 2013 Robotics Business Review Game Changer Award and the Ernst & Young Entrepreneur of the Year 2012 in Region Funen.

A Mobile Computing Framework for Pervasive Adaptive Platforms

Ubiquitous computing is now the new computing trend, such systems that interact with their environment require self-adaptability. Bioinspiration is a natural candidate to provide the capability to handle complex and changing scenarios. This paper presents a programming framework dedicated to pervasive platforms programming. This bioinspired and agentoriented framework has been developed within the frame of the PERPLEXUS European project that is intended to provide support for bioinspiration-driven system adaptability. This framework enables the platform to adapt itself to application requirements at high-level while using hardware acceleration at node level. The resulting programming solution has been used to program three collaborative robotic applications in which robots learn tasks and evolve for achieving a better adaptation to their environment.

A software system for collaborative robotics applications and its application in particle swarm optimization implementations

This paper presents a particle swarm optimization (PSO)-inspired multi-robot search application based on an innovative software system for collaborative robotic applications. The system has a multi-layer architecture which provides low- and high-level interfaces to the robots, resource (robots) management, security policies and concurrent robot access. The main result is the successful testing of the PSO-inspired algorithm on real-world experiments, using Khepera III and e-puck robots. Simulated results obtained in other studies are therefore validated by the real-world experiments. Differences between simulation and real-world experiments are presented and discussed critically.