“In the robotics community, these motions are largely ignored due to their complexity,” Callen Fisher, a PhD student on Patel’s team, says. “In the bigger picture, it’s not useful to have a robot that can run very fast if it needs a few minutes to reach that speed or to slow down from that speed. We are trying to solve that by developing novel controllers and platforms.”
Designing a robot
The first step in achieving this is Baleka. Named after the Zulu word for ‘sprint’, Baleka was designed by master’s student Alexander Blom as a platform capable of testing controllers for these agile motions.
It took two years to develop and create Baleka, with at least one year dedicated to design and optimisation.
“It was really difficult to do, because no-one knows anything about rapid acceleration motions,” Blom says. “We had to develop an entirely novel way to design the robot. By testing acceleration and deceleration motions, and trying out different leg lengths and gear ratios, we could identify what we needed to build.”
The build work was novel in its own right, and sent Blom to the Institute of Electrical and Electronics Engineers’(IEEE) 2018 International Conference on Robotics and Automation in Brisbane, Australia.
“We were the only African university represented there, which is a testament to this work being sufficiently novel and interesting,” Patel says.
The first step
Baleka was designed with one key purpose in mind: to be capable of demonstrating specific transient movements.
“That means how high it can jump and how repetitively it can do that,” Blom says.
This, however, is just the first step. The team will now use the work that went into developing Baleka to develop a quadruped robot for testing how the spine is used in transient motion.
“Alex has designed a leg that can handle a range of motion with a spine attached to it. Now we’re going to build on that to identify the optimal spine to support rapid acceleration and deceleration,” Fisher says.
Baleka will also be put to further use. Stacey Shield, another PhD student on Patel’s team, will use the robot to test how arms affect motion. Specifically, she’ll look at the role of arms in stopping and how arms can assist with acceleration.