Rickertsen2
30-03-2006, 22:09
Now that the build season is over i am looking for some interesting project to occupy my time. One thing that came to mind was a mini rc segway about a foot or so tall. I figure it will make a fun toy and challenging MISO control problem.
In order for an inverted pendulum to remain stable, the sum of the horizontal forces must equal zero. On a segway, the rider shifts their mass forward to signal that they want to go forward. This moves the horizontal center of mass of the system in front of the point where the wheels touch the ground. If the segway did not accelerate, the rider and the segway would fall forward. Acceleration leads to a counterforce that balances out the falling while at the same time increasing the velocity of the system. I would assumme that eventually the segway reaches a maximun velocity and stops accelerating at which point the center of mass must once again be above the wheels. The decelleration process is the reverse.
All of this is just inference and assumptions. I have never even ridden a segway before and don't really have a clue how the balancing works.
This is all fine and dandy until you remove the rider as would be the case in my robot. Now you have nothing to shift the center of mass in front of the the wheels during acceleration. The only way i can think of to make the thing drive forward is to first jerk backward. I cannot fathom a reasonably intuitive remote control scheme that would accomplish this. I have considered an actuated counterweight but would prefer to avoid this.
http://www.segway.com/products/rmp/
That works somehow without a counterweight
In order for an inverted pendulum to remain stable, the sum of the horizontal forces must equal zero. On a segway, the rider shifts their mass forward to signal that they want to go forward. This moves the horizontal center of mass of the system in front of the point where the wheels touch the ground. If the segway did not accelerate, the rider and the segway would fall forward. Acceleration leads to a counterforce that balances out the falling while at the same time increasing the velocity of the system. I would assumme that eventually the segway reaches a maximun velocity and stops accelerating at which point the center of mass must once again be above the wheels. The decelleration process is the reverse.
All of this is just inference and assumptions. I have never even ridden a segway before and don't really have a clue how the balancing works.
This is all fine and dandy until you remove the rider as would be the case in my robot. Now you have nothing to shift the center of mass in front of the the wheels during acceleration. The only way i can think of to make the thing drive forward is to first jerk backward. I cannot fathom a reasonably intuitive remote control scheme that would accomplish this. I have considered an actuated counterweight but would prefer to avoid this.
http://www.segway.com/products/rmp/
That works somehow without a counterweight