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Does the humanoid robot idea really have legs?

Chris Middleton Profile picture for user cmiddleton July 18, 2022
They’ve got legs and they know how to use them. But why do some robots need to look like humans, or animals, in the first place?

Image of a robot
(Image by StockSnap from Pixabay )

Since Czech writer Karel Čapek’s play Rossum’s Universal Robots coined the word ‘robot’ into popular usage in 1920 (from the Slavic root ‘robot-’, meaning forced labour), the science fiction conception of a robot has been a humanoid machine, like the Maschinenmensch (aka Maria) in the 1927 film Metropolis, or, as in Čapek’s play, an artificial person created to work for us.

But in the real world of robotics – of industrial and logistics devices, drones, automation software, and more – is there any need for humanoid robots, or devices that have arms and legs?

Beyond humans’ centuries-old quest to make models of themselves as an engineering or artistic challenge – automata, for example – do humanoid, anthropomorphic, or zoomorphic (animal-like) machines serve a real purpose? We’ve seen them in videos running, jumping, somersaulting, and sometimes falling over, but what might they do for us, beyond entertaining or terrifying us?

A new white paper explores these issues and provides some answers. ‘Legged Robotics: Agile and Dynamic Interaction’ has been published by the UK-RAS Network, the unit inside the UK’s Engineering and Physical Sciences Research Council (EPSRC) that focuses on robotics and autonomous systems.

So why do some robots need limbs to move about, rather than wheels, tracks, rotor blades, or wings? The short answer has less to do with human vanity than with logic, despite the significant engineering and safety challenges involved. The human environment – at least, the able-bodied one – is designed to be navigated with legs and arms.

The paper explains:

One of the main drives for this research field is that our world is largely built with the human morphology in mind. Staircases, doorways, counter-tops and workstations are all built around the typical size of a human adult. Mobile robots in the homes and offices of our future need to adapt to our space, rather than the other way around.

Fair point, though it does still beg the question: why would humanoid robots be sitting in an office in the first place? It’s a science-fiction vision that lacks common sense. Why not just employ a person?

Meanwhile, the market for domestic robots that can move about and interact with us is both overcrowded and unproven. Few, if any of them, do enough to justify the expense; there’s little utility in the concept. The same applies to public service robots in hotels, stations, and shopping malls. People approach them with 100 years of science fiction in mind and find the real-world experience boring and disappointing

That aside, progress towards industrially feasible, technologically advanced walking robots is undeniable, says UK-RAS. Legs can help robots move across rough, complex, and unpredictable terrain better than wheels or tracks.

While Boston Dynamics’ Spot quadruped (one of the few such robots to have established a viable market) and the Atlas biped have achieved “a type of narrow, superhuman athleticism”, other companies such as ANYbotics, Unitree Robotics, and Ghost Robotics target specific segments: for example, industrial inspection, low-cost platforms, and military applications.

UK-RAS continues:

The key development which has enabled rapid progress is force sensing and whole-body balancing control. These core technological components have enabled compliant and flexible locomotion. Modern walking robots now adapt to the world's complexities rather than being brittle to the unexpected.

Embedded compute in small form factor, industrial grade depth cameras, high-quality MEMS IMUs, and lightweight materials are other components which have contributed to the commercialization of this generation of walking robots.

Useful and intelligent 

Within the UK, there is a vibrant research community working on legged robots, and also on robotic hands and grippers; the UK’s Shadow Robot Company is a world leader in the latter, for example. The Edinburgh Centre of Robotics, the Robot Intelligence Lab at ICL, the Real Robotics Lab at the University of Leeds, the Oxford Robotics Institute, and UCL are among the academic hotspots, as are Bristol, Plymouth, Manchester, and Reading universities. In addition, the UK has four overarching robotics hubs.

Promising applications might include safety, maintenance, and inspection in the oil and gas sectors (where automation is the clear direction of travel for corporations), nuclear decommissioning, and other extreme environments, such as deep mining, satellite maintenance, and deep-sea engineering. Two of the UK’s academic hubs are centered on nuclear applications.

The white paper says:

Removing humans from harm’s way is a common trait of our research field. Several legged robotic platforms have shown great capabilities and robustness in operating in challenging or hazardous environments.

In addition, the defence and security communities face risks on a regular basis, as a result of investigation, monitoring, or patrolling.

Telepresence in robotics has the potential to provide further solutions. While full autonomy is challenging to achieve, remote physical teleoperation can be useful in many circumstances, says UK-RAS:

The Defence Science and Technology Laboratory (DSTL) has been exploring the use of innovative telexistence solutions that would give military personnel, emergency services, or humanitarian workers the ability to operate in hazardous environments without physically being present.

The TeLeMan (Teleoperated Legged Manipulator) robot developed by the University of Leeds and University College London explores teleoperating a legged manipulator to tackle this challenge. The system consists of a quadrupedal legged robot with a robotic manipulator, and 3D sensing, as well as a human operator with an inertial-based motion capture bodysuit and virtual reality headset.

In particular, TeLeMan aims to understand the capabilities of such a system for defence and security with applications in real-world scenarios. As a proof of the concept, the research team are studying if Explosive Ordnance Disposal (EOD) can be achieved out of line of sight in this manner.

Humanoid machines, such as NASA’s female-formed Valkyrie, are being developed to work alongside humans if and when Mars colonization becomes feasible, and may also have applications in bomb disposal and other dangerous activities. Limbed robots could also work alongside human workers carrying heavy objects in warehouses and factories, with human-enhancing exoskeletons being a related area of research.

As the paper explains, all these research areas are about keeping humans away from extreme, hazardous, or lethal environments, or giving them a safe presence within them; the opposite of the Terminator trope.

However, another question asked by people nervous about the negative stereotypes pushed by moviemakers and tabloid journalists is, why do any robots need to be autonomous or intelligent?

One answer is physics. The further away a robot is from a human operator, the harder it is to control it in real time: on Mars, for example, a delay of up to 14 minutes for signals to arrive from Earth means that rovers need to have a degree of autonomy to achieve mission objectives. The same applies in some hazardous environments on Earth: under the sea, for example, as radio waves propagate poorly in salt water.

Autonomy and swarming behaviours may also make some robots smaller, faster, and lighter, because they would need to carry less hardware and therefore use less power.

That said, there may be real-world risks ahead. The US Army, via its ARL research facility is among those exploring the development of robots that can move around with autonomy, follow verbal instructions, and converse with human soldiers. I know, as I’ve been there, and the military have put some of this research in the public domain.

As ethicists have pointed out, individual innovations on the battlefield can be justified on logical grounds, and even on moral and ethical ones – keeping soldiers out of harm’s way, for example. If a squaddie can simply tell a robot, verbally, to walk towards a building, turn left, and then patrol an area and report back, then that soldier doesn’t have to carry kilos of bulky, heavy kit and sit with a laptop and a joystick.

But taken together, such innovations may, over time, add up to a significant moral hazard. At what point might we, in the real world, have given machines the power of life and death, as well as the power to protect us?

My take

A fascinating area that emphasises an important point: staying informed about what these technologies are actually for is vital. But equally important is common sense.

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