Pathfinder Generation #3

Pathfinder Fall 2016 Final Summary

Project Overview By Sabina Subedi, Project Manager Project Objective The Pathfinder is an autonomous rover that is self-sufficient using solar panels. The design of the Pathfinder is inspired by the twin Mars rovers “Spirit and Opportunity.” The Pathfinder will utilize navigation waypoints on Arxterra control panel to traverse through the defined course, articulating ultrasonic range […]

Waypoint Navigation

Waypoint Navigation for the Pathfinder By Jose Alcantar, Electronics and Controls Engineer Introduction: This blog post covers the proposed waypoint navigation algorithm along with some issues regarding how the GPS data was transmitted and decoded by the Arduino. Sample code and navigational calculations are included. Navigation Algorithm: When the pathfinder travel mode is to Autopilot, […]

Stress Test

Stress Test By: Nick Lukin (Design and Manufacturing Engineer)  Introduction In order to ensure that the Pathfinder chassis could support the weight of the solar panels in order to properly interface it was necessary to perform a stress/displacement test in Solidworks. The solar panels overall weight was a maximum of 50lbs. The chassis was designed […]

Form Factor

From Factor By: Nick Lukin (Design and Manufacturing Engineer)   Introduction In order to meet the requirement of the Pathfinder being dimensionally proportional to the actual Spirit and Opportunity rovers it was necessary to develop a measurement method in order to properly scale the overall design. Figure 1: Small Scale Model Analysis A small scale […]

Experiment: LiDAR Lite

By Jose Alcantar, Electronics and Controls Engineer Introduction The LIDAR is a laser range finder which can measure distances of up to 40 meters with an accuracy of ­­±2.5 cm. The device can be used via I2C interface or through pulse width modulation. The LIDAR is to be implemented onto the pathfinder for the use […]

Heading and GPS Coordinates Formatting

By Jose Alcantar, E&C Engineer Introduction: The GPS information received through the Arxterra control panel can be sent through three different data types. The first data type is a 32-bit floating point, the second is a 64-bit floating point or “double” and lastly a 32-bit integer or “long”. Depending on how the settings are configured […]

Implementing MOVE Command Firmware

By Jose Alcantar, Electronics and Controls Engineer Introduction: The pathfinder is controlled using the direction pad on both the control panel and through RC mode on the Arxterra app. When using the D-pad, the MOVE command is called from the 3Dotlibrary which is used to control the movement of the motors. Through the design of […]

Motor Control Interface

By Jose Alcantar, Electronics and Controls Engineer Introduction: To drive the six motors independently as per requirement, 3 dual motor drivers are being utilized. Three VNH5019 motor drivers will be used to control each motor along with a PCA96805 I/O expander and a hex inverter. VNH5019: The VNH5019 dual motor driver requires three pins to […]

Current Sensors Experiment

Current Sensing Experiment: Purpose: Measuring motor draw current on current sensing pins via the VNH5019 to identify no load conditions and determine no-load threshold to shut off motors. The VNH5019 provides two current pins to the user, which can be used to measure the instantaneous current absorption by each H-Bridge. Procedure: While running a motor […]

Digital Slip Differential Voltage Ratio

By: Jose Alcantar, Electronics and Controls Engineer Speed Ratio Calculation for slip differential Purpose: To implement slip differential turning, the speed ratio for the left and right set of wheels needs to be calculated. Further testing needs to be done to find a comfortable speed for the left and right wheels. Procedure: To determine the […]