An Autonomous Mobile Robot (AMR) has various components that work together to ensure smooth and efficient operation. But for these components to communicate and function together seamlessly, the robot relies on something crucial: an embedded system. In this blog post, Kayas Ahmed, Embedded Software Engineer at arculus, explains the essential functions and purpose of the embedded software in AMRs.

What is Embedded Software?

Embedded software is purpose-built code that interfaces directly with a robot’s hardware components, like sensors and actuators. Unlike general-purpose software that can handle a variety of tasks, embedded software is designed to perform one specific function with a high degree of precision and reliability. Its job is to ensure that the robot’s hardware behaves exactly as expected, every time.

Kayas Ahmed, Embedded Software Engineer at arculus, explains the role of embedded systems in arculess (our AMRs), “The embedded software communicates on interfaces, on all the components, all the sensors, on the Printed Circuit Board (PCB) in the robot. In the system hierarchy, embedded comes right after the robot's electronics, making it alive. For example, a visible function of the embedded is to control features like LED blinking and manage motor control.”

How it All Works

The embedded software ensures a predictable response time and executes its specific function by ensuring that all the different components, such as sensors, motors, and processors, communicate effectively. That is where communication protocols come into play.

Communication Protocols

Serial communication protocols are a set of rules that define how devices transmit data to each other. These protocols enable the embedded software to send and receive data from the various components of the robot in real-time.

The arculee uses different serial communication protocols to exchange data between the sensors, motors, and the Linux module, which acts as the main processor running on the PCB. Kayas mentions the following protocols:

• Universal Asynchronous Receiver/Transmitter (UART): This protocol is for communicating with the Linux module, which serves as the central processing unit of the robot. It’s lightweight, fast, and ideal for simple, direct communication.
• Inter-Integrated Circuit (I2C): This is a synchronous protocol for connecting low-speed devices, such as sensors.
• Serial Peripheral Interface (SPI): It is a synchronous serial communication protocol for transferring data between sensors, microcontrollers, and peripherals.
• Controller Area Network (CAN): Originally developed for the automotive industry, CAN is ideal for robust, real-time communication in noisy environments. It’s functions involve coordinating communication between various control units, such as those managing motor functions.

Each of these protocols has its own strengths, and the embedded system knows which one to use based on the component it is interfacing with. This layered, modular approach enables the arculee to maintain smooth data flow between all its critical systems.

Managing Complex Processes

The arculee performs complex processes, which require efficient movement of motors and the processing of data from multiple sensors. So, how does embedded software handle it all?

“To handle complex tasks, we split the problem into smaller tasks,” explains Kayas. “We use an open-source, real-time operating system called FreeRTOS, which allows us to run multiple tasks concurrently on a single microcontroller. For example, in managing LED, the task is simplified and divided into: 1. requesting a new LED pattern and 2. applying the pattern in real-time. This division of labour ensures that each part of the system operates smoothly without interference.”

In the arculee, this distribution of tasks across multiple microcontrollers ensures that the system is more efficient and can handle the intricacies of motor control, sensor data processing, and other essential tasks without interference.

The Time Challenge

One of the biggest challenges in embedded software is adhering to strict timing requirements. Kayas believes that embedded systems are all about predictability. Therefore, it is crucial to ensure that tasks, especially motor control algorithms, are executed within a specific time frame. A motor control algorithm has very strict timing needs, and executing tasks in the required time window is crucial for the system’s operation. That is why the embedded software must work perfectly to guarantee a reliable AMR with predictable response times.

Adaptation: The Key to a Successful Embedded System

Just like any tech system, AMRs also evolve. New components are added, and features continue to improve. Therefore, the embedded software must also adapt and evolve. That’s why the arculees support over-the-air (OTA) updates, allowing engineers to upgrade and enhance the software as needed remotely.

Kayas explains, “Our embedded software supports OTA updates via the Linux module. It means that when the Linux module is updated, the software for the microcontrollers is also updated, allowing us to integrate new components or functionalities seamlessly.”

This adaptability ensures that the AMR can evolve, supporting new components or features without needing a complete revamp of the entire system. An up-to-date embedded system makes it easier to ensure the reliable and autonomous function of the robots.

Bottom Line

In short, embedded software is crucial for bringing arculees to life. It ensures the robots operate smoothly, guarantees effective communication between components, and adapts continuously with the addition of new features.

Learn more in the video below!