Geoff the RoboDog

Content

 

David Carratu
Paul Gelhaus

Project Description

For this project we wanted to created a robot of an animal that we were both familiar with the movements so that we could accurately recreate them in our robot. Therefore, both us having pet dogs back home, we decided on creating a robotic dog named RoboDog.

For our structure we started by building a front frame onto the brick which houses the medium motor, which the head of the dog is mounted to. We had to reinforce this front frame with a few triangulations to make it sturdy while it undergoes the dog’s head shaking. To make the dog’s head, we used an ultrasonic sensor mounted to a touch sensor which not only gave us a lot of room for inputs on the dog’s face, but also made the dog look very lifelike. We added ears to further that effect. We then moved on to the back legs, and for this used a piston and driving rod structure which transfers the rotational motion of the motor to back and forth motion of the leg, which is hinged to a beam attached to the case of the motor and is pumped by a beam attached to the rotating element of the motor. We then built up the front drive, as initial tests with the back legs proved that legs alone would not suffice to move the robot. For the front drive we geared a single big wheel off of the left hand side drive motor, so it pulls the dog forward as the legs push it from the back. The gearing system we used is very complicated and ended up being one of the main challenges of the build. To finish it off, we mounted a touch sensor on the side of the brick towards the back that you can “pet” the dog with, and a tail mounted on a motor that hangs off the back.

Our robot employs three sensors and four motors. Our robot has a touch sensor on the nose and on its back so it can sense when someone is petting its nose or back. The robot also has ultrasonic sensors in the location of what would be the dog’s eyes - they also perform a similar function. We used two large motors to rotate the hind legs (one motor for each leg), one large motor to wag the tail, and one medium motor to shake the dog’s head. We used LabVIEW Block Diagrams to program the robot and targeted the code to the Lego Brick so that the code runs on the Lego Brick and can operate autonomously, without having to be plugged into the computer. When each of the touch tensors are pressed, both the dog’s head and tail shake repeatedly for several seconds. Also, when someone holds a bone (several Lego beams connected together) within 9 inches of the robot’s face, it will stop walking forward until someone holds out their hand in front of its face to tell it to stop moving forward.

The hardest challenge with the construction of our robot was the design and creation of the hind legs of the dog. We had difficulty getting the legs to move in a similar fashion to a dog and at the same time move the robot forward. However, we feel that our project is a success since our robot walks in a motion similar to that of a dog, can shake its head and wag its tail, and can sense and respond to the environment with its three sensors and four motors.   

Gallery
Video

 Video Presentation of RoboDog

Attachments

 LabVIEW Code

AttachmentTypeSize
robotdogcode_57e08d77a3799Robot Dog Code .vi262.89 KB

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