ME102B Final Project

Three-Legged Jumping Robot (Mechatronics Design Project

Project Overview

A three-leg jumping robot explores a form of locomotion that is rarely studied, offering a balance between stability and mechanical simplicity. Designing it presents important challenges, including coordinating all three legs, maintaining balance during loading and landing and controlling jump direction. This project gives us the chance to innovate in an under-explored area of robotics while pushing our skills in dynamics, control and integrated mechatronic system design.

Our solution concept is a three-legged robot that moves through controlled hops using a three-state control strategy: loading, launching, and landing. While loading, the robot operates DC motors to load an extension spring. For launch, a cam mechanism at each leg disengages the motor from the spring. During flight, the robot reorients itself with an IMU to land successfully and repeat the process. Future works aim to achieve precise directional control, target-based landing, and repeated hopping. We wanted to reach a jump of 5 cm at a launch speed of about 0.99 m/s.

Project Requirements

1. One moving transmission / DOF
2. One DC motor (brushed/brushless)
3. One analog input
4. One digital button input to an I/O pin
5. Microcontroller
6. State Machine and event-driven programming

Key Software / Application

1. Fusion 360 / Solidworks
Design mechanical prototypes (rigid body, bearing, linkage system, dowel pins, etc.)
2. Arduino
Finite state machine programming and integrating mechanical/electrical components together
3. CircuitLab
Circuit schematic maker and simulator

Mechanical Design

Figure 1. Full Assembly Isometric View

Figure 2. Full Leg Exploded View

Figure 3. Leg Flexion

Figure 4. Labeled Diagram of Assembly (including Electronics)

4-Bar Linkage Calculations

Figure 5 and 6. Full Assembly of Breadboard Casing + Detailed/Exploded View

Electronics + Software

The circuit connects a microcontroller to motors, motor drivers, an IMU sensor, and a button to control motion and sensing. The state transition diagram shows how the robot moves through stages like idle, windup, launch, flight, landing, and shutdown based on button input and IMU acceleration data. Together, they explain how the robot safely powers on, jumps, detects its motion, and turns off after completing a cycle or if it falls over.

Figure 7. Snapshots of Relevant Output on Serial Monitor (IMU, Motor RPM, and resulting states)

Final Deliverable + Award

Through the ME102B Project, I learned how mechanical design, electronics, and software must work together for a system to function reliably. I improved my skills in component integration by wiring motors, sensors, and drivers correctly and ensuring they communicated properly with the microcontroller. I also strengthened my software programming skills by implementing a state machine that used sensor data to control timing, motion, and safety behaviors during the jump cycle. Our team also won the Best Mechanical Design Award!

Video 1. Jump Mechanics (Click on Image!)

Video 2. Leg Full Extension Mechanism