Taking control of technology

UAVs are playing a greater role in modern domestic life
UAVs are playing a greater role in modern domestic life

Electronics and engine control system specialists, MBE Systems’ accreditation of DO178-C makes it one of only a few SMEs supplying electronics to the US defence industry. Aerospace Manufacturing reports.

Unmanned aerial vehicles, more commonly UAVs, and still more commonly drones, are playing a greater role in modern domestic life, and this role is almost certain to increase hugely.

Aerial photography is one example how drones can revolutionise business, though it goes beyond electro-optical photography to encompass radar, laser (LIDAR) and the full electromagnetic spectrum. Mapping and surveying are used in a wide range of industries, and many industries also use them to inspect areas that would otherwise be too difficult such as very high buildings.

Engine-mounted flexible circuit board assembly with integral sensing
Engine-mounted flexible circuit board assembly with integral sensing

Although drones have been around for over a century, the market took off only in 2016, reaching $18 billion worth by 2018, and it is predicted to grow to around $43bn by 2024. Despite the market widely expanding to consumer and commercial sectors, 70% of it is still linked to military applications. However, though commercial use is expected to increase hugely over the next couple of years, perhaps with door-to-door deliveries, it is also becoming more widely used within the defence forces as well.

Here they are also referred to as UAS as the system is more than the aerial vehicle - the ground control station, communications and payload are equally important. However, they are also called Remote Aerial Systems, Remotely Piloted Aerial Systems/Vehicles (RPAS) and there are subsectors such as Robotic Autonomous Systems and several other acronyms!

There is a wide range of RPAS: nano, micro, small, medium and large plus further subdivisions. The largest, Global Hawk, is a jet, the Airbus Zephyr uses solar, but most are electric using battery packs.

An eye in the sky

The predominant use of drones in the early days was surveillance and reconnaissance. Now the range of their use is extending, including search and rescue, and traffic monitoring. They are capable of roving on land, streaking through the skies, and diving under the seas and more.

Drones are becoming smaller, quieter and lighter, allowing for longer flight times and a wider range of applications. However, this is only the case when the manufacturing and testing of the drones has been done right. For example, currently in the Ukraine war it has been reported that the Shahed-136 Iranian-made drones, recently purchased by Russia and described as ‘kamikaze’, have proven to be relatively ineffective against sensitive targets.

With a range of 600 miles, a maximum speed of 111mph and costing $20,000, the drones are easily identified, easy to spot and taken down by small air-defence systems or even small arms, especially when compared to the drones produced for the US Army, with one drone costing $15m!

However, rain enough of them down on a poorly equipped country, and you can see the results on the news. There is also a cost efficiency balance to air defence. If your missile intended to bring a cheap drone down is significantly more expensive, then you may be losing the war despite short term success.

The weapon of choice

The US is renowned for its use of UAVs in military applications and could be one of the first countries to make the growing UAV technology its main weapon of choice in the coming years. Some reports show that the government spends almost $18 billion on UAVs and the military has 11,000 machines.

Highly integrated engine controller circuit board assembly with integral sensing
Highly integrated engine controller circuit board assembly with integral sensing

While the US Armed Forces use drones in its missions around the world, with further development of the technology it is possible that UAVs may be able to replace the role of the soldiers on the battlefield, completely reshaping many of the military affairs of the future.

More modern UAVs capabilities match those of humans in some situations. For example, instead of sending a group of soldiers into an area to gather intelligence, it can be performed remotely with the help of a drone. This will save both the financial resources of the army and reduce the risk to soldiers.

Like any aircraft, the engines are key to effective operation. The more effective the engine, the more effective the drone, with speed and lack of detection being key drivers of success. An interesting twist here is that the freedom of manoeuvre by an enemy can be restricted more if he knows the drone is there so it may be useful to leave them noisy. Drone engine control units (ECU), also known as engine control modules (ECM), provide electronic control of a wide range of internal combustion for UAV engines.

The primary function of drone ECUs is to control the speed and power output of the engine. The engine control system is essentially a collection of interdependent Proportional Integral Derivative (PID) control loops such as throttle position, fuel pressure, fuel quantity, ignition angle. Each loop must demonstrate stability and robustness in the event of failure of any aspect of the propulsion system.

With response times in order of 1ms to 200ms, the ECM is usually subject to the most demanding control loops on the vehicle and often to the most demanding failure recovery requirements. Applying the design rigour required to meet aviation standards of safety whilst maintaining the performance requirements of multiple interdependent control loops is a feat of engineering.

To achieve these requirements, maintaining redundancy and reliability whilst minimising size and weight of the control systems necessitates an innovative approach. That approach is often best served by small dynamic teams unencumbered by the processes and procedures employed by larger organisations.

Meeting software standards

A leader in the field of electronics and engine control systems is MBE Systems. All MBE ECUs feature lifetime onboard data logging that allows performance data to be collected for analysis and future efficiency improvement.

Again, like any aircraft, a UAV comprises the body and chassis, power supplies that can vary from a regular battery to solar, to laser beam power and various sensors such as laser, radar, camera, gyroscope, accelerometer, compass, barometer and GPS receiver.

Holding and controlling all these is the electronics and control systems. As you would expect drones use advanced computing technology, from analogue controls to microcontrollers, systems-on-chip and single-board computers.

MBE has recently secured accreditation of the US military quality standard, DO178-C, which makes it one of only a handful of SMEs that can supply electronics to the US defence industry, which is also a key stepping stone for the military of other countries.

Steve Baker, of MBE makes an important point: “We are really pleased to have secured DO178. But designing to this standard is more complex than just controlling the engine. You need to be able to design and supply the whole system, as well as the engine controllers.”

The company invested 8,500 engineering hours into the process, and it has led to a restructuring and revolutionising of systems and processes. Achieving DO-178C Design Assurance Level B (DAL-B), MBE joins only a few companies in the world that have seen the task through the final avionics design audit known as SOI#4 for engine control systems.

To give it its full title, RTCA DO-178C/EEUROCAE ED-12C has a well-earned reputation as being the most demanding software development standard in the world, requiring systematic engineering process and four formal audits at key project stages from an FAA designated representative. Which is as it should be – because the lives of soldiers on the battlefield and the defence of countries could depend on it.



MBE Systems

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