Designing and creating robots is not a simple job, and creating one that can be used on another planet comes with even more challenges.

However, NASA has revealed detailed designs behind one of the crucial components to creating its human-like space robots.

In a patent, which was recently published on NASA’s website, the space organisation details the complex construction of a robot’s finger.

The sixteen-page patent, which has been fully released, details how the joints of the finger are put together and interact with the robotic elbow, shoulder and more.

While the robot displayed in the patent isn’t described as Robonaut, it bears a large resemblance to the humanoid robot that is currently in space. It is possible the patent relates to Robonaut.

One version of the robot (R2) is already in space, and the development of future versions will be important to the success of future space missions.

In total NASA applied for 46 patents for the technology in R2, 21 of which were related to the hand.

Creating a robotic hand that is capable of completing human-like movements is one of the most complex areas of robotics, and the NASA patent sheds some light on the process, as well as the way that it thinks of humanoid robots.

Humanising the robot

In essence for the robot to count as a humanoid it needs to be recognisable as being designed to have a human appearance or traits.

The patent describes humanoid robots as having ”approximately human structure or appearance” and states that this can be a full body, a torso and the structural complexity of the robot being based upon the nature of the task that it is created for.

“The use of humanoid robots may be preferred where direct interaction is required with devices or systems that are specifically made for human use,” the patent reads.

“Due to the wide spectrum of work tasks that may be expected of a humanoid robot, different control modes may be simultaneously required.

“For example, precise control must be applied within the different spaces noted above, as well as control over the applied torque or force, motion, and the various grasp types.”

The benefits of having a humanoid robot in space come from its ability to complete the same tasks as its astronaut companions. For example, once the technology has been perfected, it is possible a humanoid robot in space could complete lengthy repairs to the exterior of a spacecraft – which would not be possible due to the oxygen that would be needed for an astronaut to undertake the work.

Repairs of this nature, or any general work, are likely to involve basic human actions, such as twisting, griping, and lifting.

Therefore it makes sense to build a robot that we are able to control in a similar way to how our own bodies work. In some of its most recent developments, NASA has been training Robonaut to perform surgery.

As we look toward the stars in search of putting humans on another planet, and in the further future the colonisation of those planets, robots that are able to aid astronauts in their daily activities will become more important as an aid to space exploration.

Building the hand

Creating a robotic hand that is able to imitate the human equivalent is a task that is riddled with difficulty.

Our hands, thanks to 27 individual bones, are capable of delicate and intricate movements in a range of different directions. Replicating this is in a robotic creation requires skilled engineering.

“A human hand is incredibly complete, which makes it a challenge to try to put all of the necessary pieces into the robotic hand and to integrate all of the actuators that allow for mobility similar to that of a human hand,” said Professor Mohamed Abderrahim from Universidad Carlos III de Madrid.

Abderrahim is helping to develop robotic hands that can be used in the future. He foresees that a robotic hand that can effectively mimic the abilities of a human hand.

NASA’s patent shows there are hundreds of parts to the robotic hand and fingers.

This hand is, naturally, connected to the overall arm of the robot, which comprises of a shoulder joint assembly, upper arm, forearm and elbow joint. The symmetrical structure on both the left and right sides is intended to be identical.

The hand has been designed, as much as possible, to be the same as a human hand. “A robotic hand assembly includes a base structure; a finger having first, second, and third phalanges,” the patent says.

It therefore follows that the size of the hand has also been modelled on that of humans. NASA says that it is comparable in size to that of “a sixtieth to eight-fifth percentile human male hand”.

In reality the hand that it depect is is 7.9in (20cm) long with a width of 3.6in (9cm).

Each finger is split into three different phalanges, in the same way human fingers are, which all have different capabilities.

Describing how a single finger works, the patent says: “a first joint operatively connecting the first phalange to the base structure such that the first phalange is selectively rotatable with respect to the base structure about a first axis.

“A second joint operatively connecting the second phalange to the first phalange such that the second phalange is selectively rotatable with respect to the first phalange about a second axis; and a third joint operatively connecting the third phalange to the second phalange such that the third phalange is selectively rotatable with respect to the second phalange about a third axis.”

This set-up allowed for a greater level of dexterity than was expected, and has seen the hand also incorporate sensors, actuators and tendons, which can be compared to the nerves, muscles and tendons that can be found in the human hand.

At the end of its fingers are touch sensors and each finger has a grasping force of 5lbs.

Developing the robotic hand

The success of Robonaut and its hands has meant that the technology behind it has also been used to create robotic gloves for human use.

General Motors and NASA used Robonaut’s tech to develop a Human Grasp Assist device, known as the Robo-Glove, to help astronauts and industry workers to easily complete the jobs they are tasked with.

The thoughts behind this include helping workers apply additional force to tasks – a valuable ability in manual work – and is expected to reduce the risk of repetitive strain injury.

Whatever the timescale on the development of robotic hands is, getting a hand to work in a natural human-like manner is becoming more of a reality.

NASA will continue to stretch what is possible and this will then filter down to commercial applications in everyday use.

When the robotic hand is perfected it will allow humans, on Earth and beyond, to take a more hands-off approach.