Senior Design
The Jumping Jack robot is an eight-legged symmetrical robot designed to complete jumps onto platforms between 30 and 40 inches high and between 20 and 30 inches away. Made of ABS plastic legs and a 3D printed chassis, the robot uses sensors to autonomously detect its distance from an obstacle, the height of the obstacle, and the robot’s orientation with respect to the ground and the obstacle. Using motors within each of the legs, the robot will compress a spring resting on each of the telescoping legs to it’s desired compressed length. A secondary motor will be used to adjust the length of the robot’s legs, and in turn, adjust the angle and orientation of the robot’s jump. The primary motors attached to the spring will then release the spring, which will apply a force and propel the robot into the air towards the top of the obstacle. Once the robot has landed, it will once again determine its orientation with respect to the ground, and determine if there are any other obstacles that it could, in theory, jump onto from its new position.
The Jack is an 8 legged, autonomous jumping robot, capable of jumping up to 40 inches while carrying a small payload.
Cage Chassis:
Removed material, lighter design
Internally attached sensors
Telescoping Legs
Adjustable jump angle
Nested tiers minimizes overall size
Symmetry
Always lands right side up, ready to complete secondary jump
Drawings
Tolerance Study
A tolerance study was performed on the leg to determine the diameter of the third tier of the leg
The diameter was calculated to be 0.75 inches with a tolerance of ±0.064 inches
Equation:
Gap = (1)A+(1)B+(1)C+(1)D+(1)E+(1)F+(1)G+(1)H+(-1)I
Gap =(1)(0.06)+(1)(0.375)+(1)(0.002)+(1)(0.118)+(1)(0.118)+(1)(0.002)+(1)(0.375)+(1)(0.06)+(-1)(-2.00)
Gap = -0.75
Tolerance =0.01+0.01+0.002+0.01+0.01+0.002+0.01+0.01+0=0.064
Coding
While the Arduino assembly contains 16 motors, 6 ultrasonic sensors, and 1 gyro, in order to actually complete a jump, only 1 ultrasonic value is needed, and only 8 motors are needed. The program doesn’t know the robot’s orientation to start out with, however, so it needs to be told to check. To do so, it checks which ultrasonic sensor is reading a distance less than the maximum distance that an ultrasonic facing the floor would read. From there, it reads the bottom ultrasonic’s four adjacent ultrasonic sensors to see which one has the smallest reading. That ultrasonic sensor is the one facing the object that it must jump over. Knowing the faces pointing toward the ground and the object allows the program to identify which of the motors are needed to jump, as well as their position on the robot (front right leg, front left leg, back right leg, back left leg).