RYH: Mechatronics – Electronic ARTrium

Raise Your Hand: Mechatronics

The Electromechanical Team’s goal was to build various mechatronic props and characters, including the blooming flower, the waving flower bush, the funky tree, the bright-eyed owl, Snowy the Owl, the Poisson mushrooms, and the spinning mushrooms.

Interactive Blooming Flower

The Interactive Blooming Flower was an interdisciplinary capstone design project in Fall 2022. The project had four goals:

To create a lifelike and visually appealing flower model that conceals the underlying mechanical mechanism
Have the model bloom open and close in a realistic and natural manner in response to a visitor’s relative hand height. When the visitor raises their hand, the flower should bloom, and when the visitor lowers their hand, the flower should close.
The model should be robust enough that it can be transported and operated repeatedly without risking damage.
Be able to interface with the rest of the exhibit’s preexisting Ethernet network, which would deliver commands to the flower.

The flower employs two blooming mechanisms: a pushrod and hinge system that provides most of the actuation for petal motion, and a Flexinol wire on the petals, a memory alloy enabling the flower petal to curl. The flower is constructed out of steel, brass, and 3D printed parts to give the flower robustness. Control is managed by an Arduino Uno with an Ethernet adapter. When the participant enters the exhibit, current through the Flexinol wires increases, causing the Flexinol to contract the petals into a bud state. When the participant raises their hand, the current in the Flexinol is shut off, allowing the petals to relax, and a linear actuator pushes up a rod, causing the flower to open.

Flexinol was chosen because it can heat up to a temperature of 90 degrees while producing no smoke, so it can be reliably used without fear of it becoming a fire hazard. However, the Flexinol is unable to create the desired range of motion by itself. This is where the pushrod and hinge system come in, providing most of the actuation for the flower. The pushrod (stem) is mounted to the base and controlled by a linear actuator, enabling the flower to open and close.

The linear actuator pushes upwards a circular ring that serves as a hinge to the petal rods, creating rotational motion for each of the petals. Each individual petal moves from 0 to 90 degrees.

Lovely Interactive Worm

The Lovely Interactive Worm was an interdisciplinary capstone design project in Fall 2022. Located in the third section of the Raise Your Hand Exhibit, the Lovely Interactive Worm responded to the participant’s head location. The worm robot remains hidden in a tree until the presence of a participant is detected in the section. At that point, the robot will emerge, revealing its lit eyes and blinking eyelids and moving its head and body in conjunction with the participant.

Originally, the ROS2 (Robotic) Operating System) system was used due to the high amount of devices and systems integrated together. However, due to its complexities and steep learning curve, the choice was made to instead use UDP communication with Mediapipe and Unity. This would allow cameras, speakers, Arduinos, and many other devices to communicate with each other. Because of the need for the robotic worm to quickly react to participant movements, all processing should be done on a computer rather than an Arduino to reduce processing delay.

As stated earlier, the Lovely Interactive Worm must be able to exit and enter the tree upon detecting the presence of a user in the section, and once fully exposed, the robot must be able to mimic the motions of the user’s head across at least one plane of motion while blinking its glowing eyes.

The following lists information about the various concepts created to fulfill the requirement of facilitating the robot entering and exiting the tree.

Rack and Pinion Gear System: Uses 3D printed rack and pinion gear to raise the Lovely Interactive Worm out of the tree and allow it to emerge without obstruction.
Linear Actuator with Lead Screw Design: Uses a linear actuator in combination with a lead screw to provide vertical horizontal movement to push the Lovely interactive worm out of the tree.
Lead Screw with Inclined Basement Design: Uses a lead screw on an inclined basement to provide movement to push the Lovely Interactive Worm diagonally out of the tree.

Likewise, there were also several concepts created envisioning how the robot would be able to move the user’s head motion across at least one plane of motion.

Wooden Snake Toy Body: Uses a design like the common wooden snake toy to mimic the organic motion of a worm head moving side to side.
Single Section of Circular Tapered Disks: Uses circular, tapered disks controlled through wires to puppet the worm up, down, left, and right.
Dual Sections of Circular Tapered, Disks: Uses two sections of circular, tapered disks controlled through wire to puppet the worm up, down, left and right. The addition of the extra section allows more movement in the body of the worm, increasing range of motion.
Final Design: Similar to the previous slide's designs but with upgraded motors to handle higher torque, a connection to the base, and addition of shells. The rear plastic spine buckled under the load, so it was replaced with a rigid spine.