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Project2: The Walker

Ziyi Zhang Rui Shi

31/1/2018

Description

Our robot is a walker which is driven by two motors. To simulate the move of animals, we use four legs rather than wheels or tracks to achieve the walking function. Through control the motors with Python language, the robot can accomplish functions of walking forward and backward.

We use pedals as our robot's front feet to keep balance and stable while walking. We connect the one side legs to one gear and connect the gear with one motor. This design can ensure coordination. To make the walker move more efficiently, back legs of the walker is triangle in shape. While walking, the area where the back foot touches the ground is very small, which offers more power to the walker.

Construction

Basically, our robot has three main components. Motors, controller, and four legs. Motors are fixed on the body of controller. We used some bricks and sticks in front of and on the back of the motors to reinforce them so that they won’t dislocate during the walking process. Two gears are installed on the motors to drive our legs. Each front leg is connected directly on the gear, and the back leg is installed on the front leg to ensure two legs can walk consistently. The main technology we use is the crank mechanism which can efficiently convert the rotation of gears into straight motion. Since both legs are also attached with the ‘’body” of the robot, they can rotate for a small angle and walk like animials

Thinking Process

At first, we challenged to use only one motor to achieve the functionality of walking. However, we faced a lot of trouble with fixing the motor on the body and controlling the four legs to move differently as we thought. Therefore, we finally decided to use to motors. Also, we tried to use gear set to move the legs, but we failed when trying to fix all the gears we want on the body due to the irregular shape of the motor and we couldn’t control the distance between the legs because the width of gears is definite. Lately we found that crank mechanism is suitable for this situation. Another problem we encountered is the shape of the legs, at first, we used a shaft to support the whole robot, but it was really unstable. However, four rectangular bricks will make the robot hard to move, we tested a lot of combinations and this one we finally used is the best one.

Images

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Side view:

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Rear view:

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Side view:

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Video Description

Code

Our code can drive the motor to achieve normal speed movement, high speed movement and move backward. The two motors are connected to port A and port B. We can see from the video that our robot can have better performance when move at high speed, and it can also walk smoothly when move backwards.

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