Autonomous Systems Scientist (A&K Robotics) Lingkang Zhang has designed and built over a dozen robots over the years that range from bipedal and quadruped to rovers and drones. His latest creation is Quadruped Robot Tsuki — an ROS-enabled, highly dynamic robot that builds off his previous quadruped design (Quadruped Kaze), only it’s stronger, faster, and more robust. It’s also wholly position controlled, with no contact sensors on its feet, or any IMUs for that matter.
Tsuki was designed using Fusion 360, has 12 degrees of freedom, and is equipped with 12 RDS3135 servomotors that act as actuators for the 3D-printed legs, which are also outfitted with metal shock absorbers/dampers to help reduce the amount of torque required to actuate each leg. A 3D-printed torso reinforced by several carbon fiber tubes makes up the body of the robot, which houses all the necessary hardware that drives Tsuki.
Tsuki is outfitted with the same motor driver system as Kaze, which includes an Orange Pi Zero Plus 2 to control the robot, and an Arduino Pro Micro with Adafruit PWM Shield to convert the signal from the Pi to drive the servomotors via I2C.
On the software side, Zhang explains, “No IMUs or foot contacting sensors are used at the moment. All the control is simply “position control,” not force control involved. The basic idea is to imagine the four legs are four robotic arms and take turns to lift up or move forward. ROS is being used for the high-level control.” Zhang says he may open source the code he used for Tsuki at some point in the future, but those interested can check out a similar solution he created for his earlier Quadruped 9g robot.