Boston Dynamics’ SpotMini, with its disturbing resemblance to a deadly quadrupedal robot that starred in the “Metalhead” episode of Black Mirror, has new competition in its territory: ANYmal, designed by the Robotics Systems Lab at ETH Zurich University. They both have four legs. They both look somewhat like a dog. And they both have arms that let them open doors, operate elevators, and manipulate objects. How were the engineered designs of these two canine-like robots compare to each other — and is there any danger of them hunting us?
ANYmal supports different gaits, allowing it to manoeuvre on a wide variety of both indoor and outdoor terrain. It is also is ruggedized and sealed against both dust and water ingress (IP67 protection). It can travel of speeds up to 1 m/s (about as fast as a human walking quickly) on two to four hours of battery power. ANYmal can be set up with either stereo cameras or LIDAR so that it can map its environment in 3D. These features aid with both localization and path planning.
This robot has been designed with torque controllability and compliant behaviour to better support safe human-robot collaboration. All the joints can rotate 360° for extreme manoeuvrability, and like SpotMini, ANYmal is all electric with no hydraulic actuators. ANYmal runs UBUNTU, is ROS-enabled, and has an open-source modular software framework.
ANYmal’s mechanical components are primarily made from aluminium and carbon fibre, weighing in at just 30 kg, but still able to support a payload of up to 10 kg. At it’s smallest (when lying down), ANYmal is 80 x 60 x 40 cm. Standing, it’s 80 x 60 x 70 cm without its arm. In short, it’s about the size of a mid-sized dog — and looks somewhat like one, too, except for the arm where its head would normally be.
ALMA is the term for ANYmal when its articulating robot arm is attached. ALMA stands for Articulated Locomotion and Manipulation. This articulating arm is what enables it to open doors and cooperate with humans on lifting objects. In some situations, it can also help it manoeuvre through challenging terrain.
Unlike the robotic dog from Dark Mirror, ANYmal is not designed to hunt down human beings even though it has been designed for autonomous operation. Instead, its designers envisioned it as an inspection robot with supporting visual, thermal, and auditory inspection skills. It can also be used for 3D mapping, remote object detection, and even gas detection. And ANYmal is already available for purchase.
SpotMini has been in the public eye a little bit longer than ANYmal. SpotMini first appeared in 2016, and its futuristic panelling made it look more polished than most of the Boston Dynamics creations, which usually allow the inside components of the robot (wires, actuators, PCB boards, etc.) to be readily visible. Because of this panelling, it looks even more like the evil dog robot from Black Mirror than ANYmal.
SpotMini seems to have been descended from BigDog, which debuted in 2005. BigDog was, as the name implies, much larger and designed to act as a pack mule for soldiers in the field. Anyone who has watched videos of BigDog in action knows it was not designed to be a stealth robot. SpotMini, however, is much quieter.
For environment mapping and path planning, SpotMini uses a stereo camera and depth cameras. It is reportedly waterproof, but not made for a rugged operating environment like ANYmal. SpotMini can run for about 90 minutes, depending on the tasks it is performing.
SpotMini has a variety of sensors to provide feedback, including force and pressure proprioception sensors in its limbs that, among other things, allow it to recognize the position of its limbs relative to itself. In addition, SpotMini is all electric, with no hydraulic actuators.
SpotMini weighs in at about the same as ANYmal: 30 kg with its arm. It can, however, support a slightly higher payload of 14 kg. In terms of height, SpotMini is 84 cm, making it about 14 cm taller than ANYmal. It is also about the size of a medium-size dog.
Like ANYmal, SpotMini has an articulating arm, and it provides five degrees of freedom. It seems that someone with artistic flair made the top part of the end effector appear as if SpotMini has rather large eyes, but that isn’t where its visual system is located. However, Evan Ackerman noticed what seemed to be a camera mounted inside the end-effector.
SpotMini is also designed to be autonomous. The future envisioned for SpotMini involves performing supporting tasks in a home or office environment where a larger robot would be difficult to use. Hunting human beings is not currently a part of its design, and fortunately for humankind, it hasn’t been weaponized. SpotMini will be released for sale in 2019.
SpotMini versus ANYmal
Both SpotMini and ANYmal are able to move their bodies around while keeping the end-effector of their articulating arm stationary, which is a significant technological achievement for both robots. They also have excellent mobility over a variety of terrain types that include manoeuvring up and down stairs. However, they were designed for very different work environments, which is reflected in the more rugged, waterproof design of ANYmal. And the technology within them is quite different. For example, ANYmal depends heavily on torque sensors while SpotMini uses more force and pressure sensors.
Their purposes are quite different, despite any physical resemblance they may have to each other. SpotMini was designed to be a house and office robot, able to autonomously navigate the complexities of an office and interact readily with doors and elevators. ANYmal, on the other hand, is primarily a rugged inspection robot that can be sent out to perform autonomous inspections.
ANYmal and SpotMini do look similar to each other (and look similar to a domesticated dog), but the technology that drives them and their operational goals are quite different. While one is designed for rugged inspection work, the other is designed to act as an assistant in a home or office environment. Engineers are continually creating and building more innovative smart assistants that make our lives more convenient. It will be interesting to see how widespread their use becomes, and whether or not we end up with a four-legged, one-armed robot in our homes or offices.