Charlie

A robot in with two legs and hooked arms bends over in a moon-like environment to be in quadruped form. — An ape-inspired robot. Photo: Daniel Kuhn/DFKI

Charlie is a legged robot that can switch between quadrupedal and bipedal locomotion. Just like a chimp, it moves around on all fours, and when it needs to grasp something, it uses its forelimbs.

Creator

DFKI Robotics Innovation Center

Year

2012

Country

Germany 🇩🇪

Categories

Features

A series of images show a spin of a robot with two legs and hooked arms bent over to be in quadruped form. — See a 360° view of Charlie. Photos: Annemarie Hirth/DFKI

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Did you know?

Charlie is based on a chimp, but its creators were inspired by an earlier project that involved a robotic scorpion.

Electronics seen on the robot. — Close-up view of the robot's spine. Photo: Daniel Kuhn/DFKI

History

The researchers at the German Research Center for Artificial Intelligence (known as DFKI) who built Charlie have a long history of studying legged robots. One of their first projects, more than 15 years ago, involved teaching a hexapod to walk on different kinds of terrain. Next they developed robots with eight legs based on the biological model of the scorpion. Those projects showed that legged robots can improve their agility by monitoring the contact forces between their limbs and the ground. With Charlie, the DFKI team wants to develop sensor-packed feet that precisely keep track of ground forces. The robot will be able to react to these forces using active mechanisms like a flexible spine. Charlie, which is part of DFKI's iStruct (intelligent structures) project, will help researchers develop control approaches for quadrupedal and bipedal locomotion and, they hope, provide insight into the evolution of walking in humans.

Specs

Overview: Equipped with a mechanical spine that bends in multiple directions and measures the applied forces and torque. Feet have embedded tactile sensors.
Status: Ongoing
Year: 2012
Website: robotik.dfki-bremen.de/en/research/robot-systems/charlie
Width: 44 cm
Height: 75 cm (quadrupedal posture) 130 cm | 51.1 in (bipedal posture)
Length: 54 cm
Weight: 21.7 kg
Speed: 1 km/h
Sensors: Torso: two inertial measurement units (IMUs) for 3D orientation and 3D acceleration. Limbs: 6-DOF force/torque sensors. Feet: tactile sensors, acceleration sensors, and absolute encoders. Spine: force sensors. Additional current, position, and temperature sensing on each joint.
Actuators: Seven brushless DC motors on each posterior limb; 4 brushless DC motors on each anterior limb; 6 brushless DC motors for spine actuation; 6 brushless DC motors for head actuation.
Degrees of Freedom (DoF): 36 (Head: 6 DoF; Posterior Limb: 8 DoF x 2; Anterior Limb: 4 DoF x 2; Spine: 6 DoF)
Materials: Spine: carbon fiber and aluminum. Body and feet: aluminum. Legs: milled aluminum and plastic.
Compute: ARM Cortex-A8 and wireless 802.11b/g inside torso. Custom FPGA-based controller on each joint.
Software: Linux OS and custom control software with C, C++, and VHDL.
Power: 48-V 2400-mAh lithium-polymer battery, 1 hour of operation