Pi Zero controlled
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This 4-legged, 8 degrees-of-freedom (8DOF with 4 legs, each with hips and knees) walking robot was 'inspired' by the various Arduino MiniKame robots that can be found on the web.
The main 3D printed body is a new custom design that accommodates:
- a Raspberry PiZero,
- a PCA9685 PWM control module for the 8 servos, plus
- separate power sources for the Raspberry Pi and the servos, as well as
- an ultrasonic sensor
- a holder for a wireless controller/gamepad USB dongle
- an OLED, and
- 3 slide switches for on/off and operational mode control.
The quadrabot's eight servos move the four legs, each with a 'hip' and 'knee' joint where the movement mechanism or 'gait' is best described as a creeping style, and a spreadsheet has been used to tabulate how a defined set of leg movements are converted into a set of individual servo movements that are then used in the control code to create 'walking' functions.
Additional 'mount' components have been designed to attach the various components to the main body, a number of design tweaks were made to the leg and hip components so that they are more easily 3D printed, and 'channels' were incorporated into the hip and leg prints so that the servo wiring could be threaded internally through to the PCA9685 in the main body.
It should be noted that the overall assembly has been evolved over an extended period of time with the wireless controller ‘dongle’ holder and OLED 'bolted on' to an earlier overall arrangement, so some 'consolidation' of the 3D print designs would certainly be possible! All the current 3D print designs can be downloaded from the Prusa web site here.
A Python and Flask web server software development, with all the code and associated documentation and images downloadable from this GitHub repository, allows the following usage options:
- demo mode: running through a set series of 'moves' as shown in the video clip below - simply activated by a slide switch setting;
- autonomous mode: that lets the quadrabot roam on its own using the ultrasonic sensor to avoid obstacles - also activated by a slide switch setting;
- wireless controller mode: allows the quadrabot to be controlled by a handheld wireless controller (see this GitHub link for more details) - also activated by a slide switch setting;
- web mode: initiated by another slide switch setting, that starts the Flask web server which allows the quadrabot to be controlled from a browser running on another device ('phone, tablet etc.) that is connected to the same network as the quadrabot.
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| 8DOF quadrabot demo routine with the robot taking a bow at the end  |
Walking robot projects:
Robotics projects:
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