Welcome to the SkiBot
A Senior Project
Meet The Team
Team Leader
Caleb Bump
I am a senior in the Electrical Engineering program. I am responsible for writing the software for GPS navigation, and the linear actuators, as well as assisting with the construction of the frame.
Problem Statement
What Do We Need To Do?
Design and build a robot that skis and remains upright, stops when needed, avoids obstacles, and follows a predetermined path down the mountain.
The selected path will be chosen by a trainer wearing a gps tracker and skiing down the trail first.
The robot will also be fitted with a wireless killswitch in the event of an emergency.
Solution
How Will It Ski?
Actuator between the skis causing the skis to create a plow (pizza).
This creates more surface area against oncoming snow.
More surface area equals more friction and more forces pushing back on the skis
System Diagram
The GPS allows the robot to follow a specific path. The obstacle sensors detect objects in path.
The microcontroller (MyRio) takes data from the GPS and obstacle sensors to decide the direction of movement.
The linear actuators tilt each leg independently.
The horizontal linear actuator control the distance between the skis and their angle.
Actuator movement is controlled via a motor controller.
Obstacle Avoidance
We are use two HRLV MAX-Sonar ultrasonic sensors mounted on the front of the robot at a 30 degree angle to the left and right of center. These sensors have a maximun range of 5 meters.
We are using one HRXL-MAX Sonar-WR ultrasonic sensor looking straight ahead. This sensor has a maximum range of 10 meters.
The information from the sensors is given to the micro controller and a decision is made based on the presence of obstacles and how far away they are.
When an object is detected on the side the robot will turn away from that object. When an object is detected in front of the object
Stopping and Slowing
If an object becomes present in front of the SkiBot, an attempt to stop will be the first course of action for the SkiBot. If turning to avoid the obstacle is more favorable then that will occur.
Click the arrows to the side to see more.
How Does GPS Work?
Quick Intro
The user must be in clear view of at least three satellites to locate position.
The method of positioning is called “Trilateration”.
Trilateration works by the receivers use of “time-of-flight” on the satellites radio waves to calculate the distance to satellite A and using that distance as the radius of circle A. The same is then done for satellites B and C.
The users location is where the 3 circles intersect.
The real satellites use this same method but with spheres.
GPS Navigation
GPS navigation works hand in had with the obstacle sensors. The GPS receiver is used to mark a path down a trail, that data will then be compared to the SkiBot's current location. If the SkiBot is positioned to far to the left or right compared to original path then the software will correct for the error.
Click the arrows to learn more.
Test Run
Previous test were run on rough terrain and good results were not achieved. In this test run, we pulled the SkiBot on flat ground to simulate the downward force of the hill.
Components
Parts used to create our subsystems
