In the world of Autonomous Mobile Robots (AMRs), the term "AMR backpacks" refers to a specific range of attachments that assist the robots with object transportation. To better understand how these attachments empower our arculees, we sat down with Fabian Gebert, Robotics Engineer at arculus. Here are his insights into safety requirements, customisation options, and much more.

Understanding the basics of AMR backpacks

Efficient material transport is essential in the increasingly demanding field of intralogistics. In this dynamic environment, backpacks empower AMRs to become agile material carriers, revolutionising operations and unlocking new levels of efficiency and productivity. As Robotics Engineer Fabian Gebert explains, “A backpack is an attachment for the arculee, and it’s used to detect and transport different objects.”

Without a backpack, the arculees rely on load carriers called “tables”. These large modules are particularly well-suited for applications where box transport is the primary focus and handover stations are not required. However, in the context of VNA (Very Narrow Aisle) warehouses, backpacks present a range of distinct advantages. Unlike tables, backpacks offer a compact design that facilitates agile manoeuvrability within confined spaces, thereby optimising the utilisation of the available area. They also incorporate advanced technology, ensuring secure and stable pallet transportation, reducing the risk of accidents or damage along the way.

The arculus backpack arsenal

The standard arculee S backpack is designed to transport the classic EURO and Industrial pallets (EPAL 1, EPAL 3, and HD 1208). Its integration with the robot creates a powerful combination that enables seamless transport of goods weighing up to 1 tonne. It also features an identification plate, which facilitates effortless recognition by the AMR’s system and allows for seamless integration into existing workflows.

The AMR backpack also features light-barrier sensors that ensure accurate pallet detection and proper centring, minimising the risk of accidents and damage to goods and infrastructure. It also incorporates strong grip tape on the contact surfaces, which prevents pallets from slipping off even in demanding conditions. Both features work together smoothly, delivering a reliable and secure pallet handling process.

Backpack customisation at its core

Fabian explains that the customisation possibilities of AMR backpacks at arculus are numerous: “Sometimes a customer already has some shells or environment restrictions, and then we just need to modify our prototypes in a way that fits their needs. But sometimes we get requests for entirely new and bespoke developments.”

This is exactly what happened when a customer requested a new addition to the arculus portfolio: the conveyor backpack. As the name suggests, the system incorporates a conveyor belt to enhance the pallet handling processes. Its primary purpose is to safely pick up Euro-Pallets from a fixed station and transport them to a conveyor station. There, the backpack utilises its own conveyor mechanism to transfer loads of up to 250kg, ensuring precise positioning and controlled movement.

The system incorporates two inductive sensors that facilitate alignment with the conveyor mechanism. To maintain safety, the backpack is equipped with end-stops that act as safeguards, preventing the pallets from being carried too far. Additionally, light barriers in the backpack ensure secure positioning of the pallet. The solution also features emergency stops on all sides, preventing unintended movement and providing very safe operation. With its seamless integration of a conveyor system, the solution streamlines pallet handling processes, improves workflow efficiency and contributes to overall operational effectiveness.

Testing and validation of AMR backpacks

When it comes to ensuring the functionality and safety of the AMR backpack before deployment, rigorous testing and validation procedures are essential. These tests encompass fully functional assessments, including evaluating the handover process, detecting the potential slippage of goods, assessing the alignment of loads, and determining the maximum cargo capacity.

As Fabian explains, the testing process involves various scenarios to evaluate the performance of the AMR backpack. For instance, the team uses simulations to assess its functionality during conveyor pick-ups, its ability to detect and respond to obstacles, and its stability and safety during emergency stops. The goal is to ensure the backpack remains secure while providing optimal performance in real-world situations.

Metrics of success

In addition to rigorous testing, the team evaluates the effectiveness of backpacks using various performance metrics, such as cost, manufacturability, and operation time. For this, field evaluations and simulations play a crucial role in assessing the backpack's performance. The results obtained in these procedures provide the engineers with valuable insights into improving the solutions’ efficiency. Operation time for example, measures the time required for an arculee equipped with the backpack to complete tasks such as load pick-up and drop-off. Other factors considered include reducing manufacturing costs, evaluating component feasibility, and meeting project deadlines.

"Testing and evaluating the AMR backpack are crucial steps to ensure its safety and functionality."

Fabian Gebert

Technical hurdles

The development of AMR backpacks has various technical challenges, particularly when it comes to safety assurance. As Fabian explains, “Everything we do comes back to safety. Safely detecting a station, safely detecting the object on the AMR backpack, safely detecting everything. That's one of the major challenges we face during development.”

Integrating the backpack with the arculee's control system also poses its own hurdles, particularly in software development, since communicating vital information between the backpack and the arculee's control system is critical for proper functioning. For instance, if the backpack's motor initiates movement while in a station, it must communicate this to the arculee, preventing it from engaging in any actions that could compromise safety. Effective communication and synchronisation between the backpack and the control system are essential for smooth operations.

Cross-team collaboration

The project’s multidisciplinary nature further adds complexity, requiring expertise in diverse fields such as electrical components, software integration, and mechanical design. Effective communication between teams plays a crucial role, as it ensures proper calibration and integration of all technical aspects and enables the development squad to approach challenges from various perspectives. By fostering effective communication and mutual understanding, the developers can overcome hurdles and ensure a smooth integration of the backpack with the arculee, ultimately leading to a successful and well-rounded product.

Packing it all up

The insights provided by Fabian Gebert offer a practical understanding of the arculee backpacks and their role in intralogistics. These attachments enable AMRs to become agile material carriers, offering distinct advantages over traditional load carriers. With features like accurate pallet detection, proper centring, and strong grip tape, the backpacks ensure secure and efficient pallet transport. Customisation options and rigorous testing further highlight arculus' commitment to delivering safe and functional solutions. By integrating advanced technology and fostering cross-team collaboration, arculus enhances pallet handling processes and contributes to operational effectiveness in diverse industrial environments.

As the demand for autonomous mobile robots (AMRs) continues to grow, both software and hardware development projects have become more complex and require effective management techniques. At arculus, we have adapted the popular Scrum framework to manage the development of our robot, the arculee. In this blog post, we'll take a closer look at how we use Scrum for hardware and software development in robotics and highlight some of the key benefits of using this framework.

Understanding Agile and Scrum

Scrum and Agile are two frequent terms used in the Project Management world. Although they share a close relationship and are often used interchangeably, it's important to understand their differences. In general, Agile is a mindset, a philosophy, and Scrum is a specific methodology that uses Agile to develop complex products and systems. The Agile mindset focuses on incremental delivery, team collaboration, continual planning and learning.

Many different frameworks use Agile as a basis, and Scrum is the most popular among them. It works by breaking down projects into smaller, more manageable chunks. Each part is then developed in short cycles, with each cycle building on the progress made in the previous one.

The basis of Scrum lies in empiricism and lean thinking. Empiricism is the belief that knowledge is derived from experience and practical observation, while Lean thinking emphasises efficiency by minimising waste and focusing on core elements. Scrum is also heuristic, meaning that it encourages continuous learning and adaptation to changing factors. It recognises that teams may not have all the necessary information at the outset of a project and will need to evolve through practical experience.

The arculus SCRUM playbook

The structured approach to Scrum is outlined in the Scrum guide. Although authors Ken Schwaber and Jeff Sutherland provide a set of roles, events, artefacts, and rules, the methodology is essentially flexible and adaptable, allowing teams and organisations to modify their approach to fit specific needs and circumstances. The Scrum's versatility is a crucial advantage for organisations seeking to adopt the framework successfully. Here is how we use it at arculus.

The SCRUM Team

A Scrum team is a small group of people dedicated to working on specific segments of the product. At arculus, we divided our robotics department into six smaller groups: Enablement, Functions, Embedded Software, Electronics, Mechanics, and Project Engineering. Each Scrum team has three essential roles:

• Product Owner (PO): responsible for defining and prioritising the product backlog to ensure the development team works on the right tasks according to the business needs.
• Scrum master: responsible for ensuring that the Scrum framework is followed, facilitating the events and removing any impediments that prevent the development team from achieving its goals.
• Developers: The individuals in the Scrum Team responsible for producing any component of a functional product by completing items from the sprint backlog (more on that soon).

The Sprint

The guide defines sprints as "the heartbeat of Scrum, where ideas turn into value". In more practical terms, a sprint is a time-box event during which the different teams work towards their respective targets. These so-called sprint goals provide a structured framework for teams to collaborate, plan, and deliver work predictably and consistently. At arculus, sprints have a set duration of two weeks.

The Events

Each sprint has a set of events. The first one is sprint planning, which officially begins the sprint. Scrum Master Rudolf Guth explains, "This is where the POs define the sprint goals according to upcoming product needs. The whole team can then negotiate which stories make sense and are achievable according to the sprint goals, always taking capacity or potential obstacles into account – and assuring delivery of value."

Throughout the sprint, the teams also get together in short daily meetings. The group has 15 minutes to align on tasks for the next 24 hours, ensuring everyone is on track to achieve their defined goals by the end of the sprint.

At the end of the sprint, there is the sprint review. That's where the team presents which goals it has achieved in the past two weeks. "Sprint reviews are also essential to ensure the Scrum pillars of transparency and inspection", explains Rudolf. "The whole company and other important stakeholders are invited to see what the teams have accomplished during the sprint."

The sprint ends with the sprint retrospective. In this event, the team inspects its own performance by examining the individuals involved, their interactions, the processes followed, and the tools used. This review then serves as a basis for improving cooperation during the next sprint.

Scrum of Scrums

Besides the official events described in the Scrum guide, arculus has one additional event for the teams: the Scrum of Scrums. In this meeting, each development team presents their sprint goals and focus. This helps them align on any unforeseen dependencies or potential issues which can prevent delays or conflicts. "One day after the sprint planning, one person from each team comes to this meeting to present their goals and ensure cross-team alignment", describes Rudolf.

The Artefacts

In Scrum, artefacts are tangible and transparent representations of work or value. They are created and used to establish a shared understanding and effective communication among the Scrum Team, stakeholders and customers. The three artefacts defined by the Scrum guide and used at arculus are:

• Product Backlog is a list of work the Scrum Team needs to complete to improve or finish the product. The PO maintains this dynamic list of features, requirements, enhancements, and fixes, which serve as the primary input for the Sprint Backlog. It is essentially the team's "To Do" list, and it is constantly reviewed, reprioritised, and maintained.
• Sprint Backlog is a selection of items, including user stories or bug fixes, chosen by the POs and development team to implement during the current sprint cycle. During the sprint planning, the team selects which items they will work on from the product backlog. While the sprint backlog can be flexible and may evolve during the sprint, the team's fundamental sprint goal, which defines what they aim to achieve in the current sprint, cannot be compromised.
• Sprint Goal, or increment, is a concrete step towards the Product Goal. The teams can work on multiple increments during a cycle. These goals are then presented at the Sprint Review to showcase what the developers accomplished during the sprint.

Scrum For Robotics

Scrum was initially created for software development and is still primarily used in that context. However, the framework has become more flexible and adaptable, making it suitable for other types of projects. At arculus, we have adapted Scrum for robotics development, where both hardware and software are integral components.

This adaptation has allowed us to effectively manage our projects, improve communication between our team members, and increase overall efficiency. But it didn't come without challenges. Rudolf explains, "while software can easily be iterated, hardware changes can be prohibitively expensive. That means that the hardware development teams must carefully consider the impact of any changes and plan accordingly to minimise disruption to the overall project timeline and budget." This is typically where the iterative design process takes place in order to avoid significant changes later on in the development cycle.

Another challenge comes from one of the critical principles of the methodology: breaking down tasks into smaller chunks. "Finding a way to effectively dismantle hardware tasks and present progress to stakeholders can require adaptation on the story level. It's a challenge that we are constantly working to overcome in order to ensure that we are transparently evolving with the product and effectively managing our projects.", says Rudolf.

Values And Principles

Scrum is built on a set of values and principles that guide the behaviour and decision-making of its practitioners. Despite the adaptation of Scrum to the unique needs of robotics development, Rudolf explains that such values and principles should remain untouched. Only then can the teams really benefit. The values defined by the guide are:

• Commitment to achieving the goals and supporting each other;
• Focus on the work of the sprint;
• Openness to ensure transparency and honesty within the team;
• Respect towards other team members' perspectives;
• Courage to take risks and make bold decisions that foster innovation.

Along with these values, Scrum also has a set of principles that guide the framework's implementation at arculus. These principles are:

• Control over empirical processes → making decisions based on evidence, not assumptions;
• Value-based prioritising → focusing on delivering the most valuable features first;
• Collaboration → working together towards a common goal;
• Self-organisation → taking ownership and making decisions autonomously;
• Time-boxing → helps to create a sense of urgency and encourages the team to deliver results within a fixed timeframe
• Iterative development → continuously refining and improving the product over time.

Our Pro Tip

For Rudolf, our successful use of Scrum for both hardware and software development comes from the crucial understanding that it is not a one-size-fits-all methodology. As he put it, "we always need to understand our reality, and then we need to adapt the framework to fit it."

In other words, while Scrum provides a framework and guide, it is ultimately up to each team to adapt it to their specific needs and constraints. By doing so, organisations can experience the benefits of Agile methodologies, such as increased communication, transparency, and efficiency. So, even though hardware development may present unique challenges, with the correct adaptation and mindset, Scrum can be a valuable tool for managing any type of project, including robotics.

Safety standards ensure that robots and humans successfully co-exist in the industrial world. Every (AMR) Autonomous Mobile Robot – including our arculee – must meet basic protocols to operate without endangering humans or causing material damage. But what are safety standards, who defines them, and how does arculus incorporate them into its product? This article will answer all these questions and provide insights into the impact of the guidelines for Intralogistics 4.0.

What are safety standards?

Safety standards are a set of guidelines to ensure compliance with robotic specifications. They establish protective measures taken by all agents involved – from the robot's production to customer use. The unique aspect of these guidelines is that any stakeholder (consumers, manufacturers, businesses, research institutes, and public authorities) can propose a standard. It is then reviewed and developed by regional and international experts with full consensus to reach a common standpoint.

"Simply put, safety standards are primarily concerned with protecting workers from hazardous accidents, and regulating the robot’s operation."

Martin Schöpp, our Functional Safety and Automation Engineer, who analyses these protocols and derives requirements for arculus.

A recognised European Standards Organization – CEN, CENELEC or ETSI – sets the rules for all products, services and processes in Europe. These standards are regularly updated to keep pace with advancements in the field. Guidelines for electrical safety of Autonomous Mobile Robots, for example, usually take about five years. On the other hand, general standards that apply to all machines in the EU are reviewed less frequently, usually every 15 to 20 years. This continuous review and updating of processes ensures that technology within the EU is safe, reliable and up-to-date.

Safety features of the arculee

When it comes to the arculee, arculus has integrated various features to prevent on-site injury to warehouse workers or damage to goods and premises. One of its core safety components is the capability to detect humans in close proximity, allowing the robot to behave accordingly. As Martin describes it:

"From the human safety perspective, the main capacity of the arculee is to detect a person around it using LiDAR sensors, also commonly known as safety scanners. It notes the travel speed and direction and uses that to estimate the braking/stopping distance. Based on these three factors, it evaluates if the person is inside the hazardous zone or not."

Another crucial feature is the robot's ability to identify six types of load using inductive sensors. Each load, including tables and pallets, has a different size and can be transported crosswise or lengthwise (depending on the type) on the arculee. "If a robot does not accurately identify the load type and carries a bigger load than initially estimated, it has a higher probability of crashing into a wall or a human. This is a safety function that truly saves the day.", Martin explains.

In addition to load carrier recognition, the arculee can also detect the placement of pallets via sensors in the Backpack — a piece of equipment mounted on our robot to drive pallets. These sensors are critical to placing the pallets correctly and safely transporting them to their destination. In Martin's words:

"For pallets, we extend the braking distance, and the arculee drives slower. A pallet must be placed on top of the Backpack in the centre to prevent the robot from tipping. Bad positioning can make the arculee lose its balance and potentially damage the load it is transporting. This feature enables our robot to detect if the pallets are in the right position and not drive further to prevent any accidents."

Lastly, our AMR has a safe recovery function for lifting and driving. "When the arculee encounters an obstacle within its safety fields, it signals that it cannot drive further. In such cases, the worker(s) can switch to recovery mode and manually move it out of the deadlock.", explains Martin. In case of system failure or hardware issues, the workers can use a recovery trolley to move the arculee. "The user first needs to switch off the robot to stop it from operating automatically, place the trolley beneath it, and connect the cable to the arculee. The brakes then open, allowing the user to pull the robot to the service area without creating havoc in the warehouse.", he continues.

From Regulations to CE Mark and beyond

The primary purpose of complying with safety standards is ensuring that our AMR meets all requirements to safely drive in the warehouse alongside humans. While arculus has successfully attained various certifications, one of the most significant milestones the company has recently achieved is getting the statement of conformity for the latest version of arculee by the notified body TÜV SÜD Product Service GmbH. This assures that the robot has been developed and tested for safety and complies with national and European safety standards.

"All industrial robots have to provide elementary safety functionality, and the manufacturer can declare conformity and put the CE Mark on the robot. However, not all of them are inspected and tested by a notified body, which ensures that there are no critical bugs implemented. The statement of conformity by the notified body, TÜV Süd Product Service GmbH for the newest arculee generation is a big achievement for arculus and its team."

Romano Wolf (Product Lead - Robotics)

For the accreditation mentioned above, the arculee has to comply with at least four DIN Standards (German Institute for Standardisation), namely DIN EN 1175:2020-10, DIN EN ISO 3691-4:2020-11, DIN EN 12100:1997-11, and DIN EN ISO 13849-1:2016-06.

How does arculus comply with safety standards?

The safety standards are fundamental to building the arculee. For that, it is equally important to test the robot to ensure full compliance. As Martin puts it:

"Quite often, the instructions for testing are provided by the standard itself. For example when testing personnel detection, the standard states which obstacles need to be detected, what we need to place on the floor and where. The guidelines also specify that we should test at full speed and with a 110% overload situation. And if everything runs as expected, the robot immediately stops before hitting the obstacle."

However, when no directions are given, the team is responsible for defining what tests they need to run for safety verification. "Some can be verified by doing calculations like the mechanical strength of the robot. But processes that have to do with the functioning of the arculee, or what determines its behaviour, need to be tested", adds Martin.

Some of these tests include:

• Hardware integration tests
• Type tests for European Conformity (CE)
• In-Line and End-of-line tests during production
• Release tests for potential software updates

Training for a safe and sound co-workspace

To ensure that employees are familiar with the latest safety standards, arculus incorporates them into the company's system. This makes them easily accessible to all teams at all times. Additionally, the company conducts regular training sessions led by industry experts to provide employees with in-depth information on the latest guidelines. With that, arculus employees are up-to-date with the latest safety regulations and can apply them effectively in their work.