In the world of robotics, questions often arise about walking. Surely in order to make a robot as lifelike as possible it needs to be able to walk like a human, right?

This question is probably best answered in the words of Engineered Arts founder Will Jackson, who says, “We always strive for more – more entertaining, more interesting, more capable – and more human. Enter Byrun: poised to take the next giant leap for robot-kind.”

Creating a pedal robot is no walk in the park

The thing is, creating walking robots is extremely difficult. It requires not just engineering expertise, but radical and novel approaches to the problems of dynamic balance, actuation efficiency, and locomotion.

All of this makes the process incredibly expensive. Which means that there isn’t really a business case for doing so. Even companies such as Boston Dynamics with their amazing walking robots don’t really sell any.

But, says Will, the question doesn’t go away. People are always asking of RoboThespian, “Can it walk?”

“I realised that most people would love to see it,” he says. “And they can, in perfect safety – at a show or public event. But just walking is not enough. It must run, jump, hop and leap. To be worth its cost, this robot must perform like something never seen before. If it can do just 10% of John Travolta’s walk, Margot Fonteyn’s dance and Julia Roberts’ smile, we have a winner.”

Thankfully, work like this is something that can be funded as research. And so, having secured a grant from the Technology Strategies Board (now Innovate UK), we began work on a unique parallel electric-pneumatic design we called Byrun.

Large scale problems

Take a trip to your local toy shop and you’ll be faced with a range of walking robot toys. So what’s the challenge with making them at a larger scale?

First of all, smaller things are easier to get moving than larger ones. Secondly, a toy robot isn’t walking in the same way a human does. Some older models of robots have been able to walk but not with the graceful elegance of a human taking a pleasant stroll, more with the mechanical waddle of a penguin.

A human’s walk is actually highly complex. From the moment we pick up one foot we’re essentially falling until that foot reaches the floor again. We’re constantly monitoring and adjusting our whole bodies to ensure we stay balanced. 

And there are so many variables to take into account. For example, how should a robot react if they’re walking and they stub their toe? Or if they reach an incline or some stairs? With a human brain, this is instinctive. With a robot, it all has to be programmed.

Safety first

Another challenge that faces any creator of a walking robot is the element of safety. If a robot is walking and does fall over – or doesn’t stop in time – it can be extremely dangerous. After all, we’re talking about 50kg of moving metal.

Yes, robots are heavy. In order to be autonomous they have to be, containing batteries so that there’s no need for restrictive wires. And because these batteries are located in their torso, they’re not just heavy but top heavy. Plus, the taller they are the heavier they get.

“Of course, there are some application areas where causing serious injury or death are not a concern,” says Will, only half joking. “We could create a ‘Terminator’ biped. Personally, I oppose the mechanisation of death for ethical reasons. I want to build machines that make people laugh, not cry.”

What we did to combat these challenges

Research to overcome these difficulties is important and could pave the way for future developments in walking robots. And if we do say so ourselves, Byrun really was a feat of innovative mechanics. 

In order to create a stable and safe walking robot, we used a biarticular hip-knee linkage alongside advanced force sensors to help keep its centre of mass in a stable location.

We also had to consider how the torso and upper body would affect the balance of the robot, and used a combination of SEAs in parallel with pneumatic muscles to create fast, strong and accurate joints on the robot.

There are always challenges to be faced in robotics, and we are always ready to innovate to overcome these challenges. We’re a way off from seeing robots walking down the high street, but Byrun helped move the dial forward a notch. And who knows what our research will lead to next?

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