Robohub.org
 

Compliant actuator for 1DOF hopper

by
26 September 2011



share this:

For a long time, robots were seen as rigid machines driven by sturdy motors. This raised worries concerning the safety of people interacting with them. One option to make robots safer is to equip them with compliant actuators that can adapt to external forces, such as a human getting in the way. Note that most natural systems also rely on compliant actuators such as muscles that can store energy, thereby making them more efficient for tasks such as running or hopping.

Building on the potential of safe and energy efficient actuators, Vanderborght et al. propose a new type of actuator called MACCEPA 2.0 (Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator). As seen in the figure below, when the position of the profile disk (heart shape) is changed by a servomotor or the joint is bent, this causes the tendon that is guided over the profile to pull on the spring. To counteract the pulling force, a torque will be generated that depends on the shape of the profile. To change the compliance of the actuator, simply replace the profile by another shape. Similar to what happens in human legs, the stiffness of the actuator increases with joint flexion.

Working principle of the MACCEPA 2.0. Top: Bent position (generating torque). Middle: At equilibrium position (not generating torque). Bottom: Preloaded spring caused by rotating profile.

The actuator was demonstrated on the 1DOF hopping robot Chobino1D shown below. The spring is preloaded by turning the profile using a servomotor before releasing the tension for the jump. Using MACCEPA 2.0, the robot was able to jump much higher than a robot with a stiff actuator.




Sabine Hauert is President of Robohub and Associate Professor at the Bristol Robotics Laboratory
Sabine Hauert is President of Robohub and Associate Professor at the Bristol Robotics Laboratory





Related posts :



Our future could be full of undying, self-repairing robots – here’s how

Could it be that future AI systems will need robotic “bodies” to interact with the world? If so, will nightmarish ideas like the self-repairing, shape-shifting T-1000 robot from the Terminator 2 movie come to fruition? And could a robot be created that could “live” forever?
01 February 2023, by

Sensing with purpose

Fadel Adib uses wireless technologies to sense the world in new ways, taking aim at sweeping problems such as food insecurity, climate change, and access to health care.
29 January 2023, by

Robot Talk Episode 34 – Interview with Sabine Hauert

In this week's episode of the Robot Talk podcast, host Claire Asher chatted to Dr Sabine Hauert from the University of Bristol all about swarm robotics, nanorobots, and environmental monitoring.
28 January 2023, by

Special drone collects environmental DNA from trees

Researchers at ETH Zurich and the Swiss Federal research institute WSL have developed a flying device that can land on tree branches to take samples. This opens up a new dimension for scientists previously reserved for biodiversity researchers.
27 January 2023, by

The robots of CES 2023

Robots were on the main expo floor at CES this year, and these weren’t just cool robots for marketing purposes. I’ve been tracking robots at CES for more than 10 years, watching the transition from robot toys to real robots.
25 January 2023, by





©2021 - ROBOTS Association


 












©2021 - ROBOTS Association