Mynock Jumping Robot

Executive Summary

For the Winter 2018 quarter for ME112, each team was challenged to design and build a mechanical jumping robot, inspired by the Mynocks found in Star Wars. The robots were required to perform a jump under their own battery power, with linkages and movement reminiscent of a chosen earthly creature, such as a frog or a flea. The primary goal was for the robot to jump 1 [m] off the ground and stick to the underside of a test enclosure using Velcro. There were additional design constraints of charging and releasing in under 5 seconds, as well as being no more than 10 [cm] in height, 30 [cm] in width, and 30 [cm] in depth in the compressed state.

Our team drew inspiration from MSU’s flea inspired jumper, prioritizing a symmetrical design and flexibility in spring placement. Our initial design relied on a crank release mechanism, similar to that of the MSU jumper. After prototyping and testing, we found that using a crank further restricted certain geometries and heights in our overall design mechanism and so we moved forward with a simpler design. We decided to load the mechanism using a pulley and experimented with various release mechanisms before settling on a sliding plates design, which worked successfully and reliably. Through our early prototyping, we also learned that we were limited in the torque-to-weight ratio of Tamiya gearbox and decided to pursue a lighter and more compact motor.

We used Matlab and Adams software to inform our design decisions regarding the motor, batteries, and spring. Our final design was driven by a lightweight Pololu micro motor with a 6 [V] 100 [rpm] rating that operates at a 298:1 gear ratio. Three E-Flite batteries allowed our jumping robot to draw currents of up to 3.75 [Amps] at 11.1 [V]. Our selected spring, with a spring rating of 332.9 [n/m], in addition to two rubber bands provided sufficient spring energy to reach the desired jumping height of 1 [m]. The jumping robot is primarily made of acrylic, with the exception of the plywood base plate, which is designed to be lightweight and durable. The robot had a final weight of 149 [g], with a height of 10 [cm] in its compressed state and maximum height of 26 [cm]. Our final prototype jumped 1 [m] and successfully adhered itself to the mock spaceship, with enough force to signify that it could jump over 1 [m]. The jumping robot accomplished this task in 7 seconds, falling slightly short of our original goal to achieve this within 5 seconds.

In our next stage design we would focus on reducing the weight of the robot by using lighter materials, in order to increase the height of the jump. Another possible next stage implementation would be to create a more stable release mechanism by replacing the wire triangle with a laser cut piece. Additionally, we would consider adding a switch to reduce the risk of damaging the motor after the jump is completed.

Video - Robot performs a 1[m] jump after preloading for ~7 [sec]