Home Up News Robotics Team Schedule Resources Community

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Drive Systems

Omni Drive, Omni Directional Drive, Omni Track,

Mecanum wheels are a manufactured wheel assembly that is now replacing Omni wheel derive system

Other Types of Drives: Omni Drive, Mecanum wheels, Front Regular & Rear Omni, Cross Omni, Rear Caster, Four to Six Wheel, Two Rotate and Casters, Four Rotate, Four Independent, All Drive

Link about omni drive: http://www.societyofrobots.com/robot_omni_wheel.shtml

 

Click here for video                             

              TEST ROBOT                    EMU 2004 XEROX CREATIVITY AWARD ROBOT

We have been developing Omni drive for many years and have seceded. The problem is that we could not find students that could drive it. The mixing control program was not sensitive and the students had trouble making short turns (to set a item on goal). They also had trouble keeping track of all the directions they that they could go. At that time we used the trigger button to go from rotate to tank style drive. The best control set up was two joysticks mechanically tied together. The left controller would mix and control the left two drives motors and the right controller would mix and drive the right motors. The mechanical tie would not allow the joy sticks to move apart or together but forward and back or side ways. So using this method was easy to program and what you could do is go forward, back, rotate, sideways and angle. We used the drives on a 45 degree angle to front and back to make use of four wheel drive in forward and reveres. On angles it would only be two wheel drive. Below are two different styles.

  Above are two joysticks and if you install the above piece (we made out of plastic) into the handle , it allows the two joysticks to go forward and back , but only allows them to go sideways together. Doing this with a simple mix program that is already in the program, you can copy and past for the second joystick mix program, you can use tank style driving but get all the directions of omni drive.

       Above: The motor is mounted inside the wheels for each drive. The wheels have a longer length and the use of four rows give more traction.

 

               Above: We C&C plastic (HDPE) and snapped the wheels into place. Each unit has two rows of wheels, one in front and one in back. With two of these units at each drive location that would be equal to four wheels at each drive giving a good amount of traction. Their is a lot of pushing power and of course lots of control. The system will go up ramps but only in a angle direction. We have developed a easy suspension that would allow for ramp use in any direction.  If you have questions contact us jkweber@charter.net

Above, the motor you see will slide into the cylinder which has the supports for the omni wheels. The triangle plate on the motor has bearings and then a bearing will slide over the tube on the end of the motor. The slot in the tube allows for contact of the gears to the motor gear. We used a 1/4 in rod for the axel with brass bearing collars. The omni wheels are PVC caps glued together and lathed for the curve. The white support was changed to aluminum on the final robot. We used this omni design on the 2005 robot. With the motors inside the wheels it left us with allot of space. Notice How the wires from the PWM go through the white base, we routed them in slots in the HDPE between the white and a top layer of Black HDPE. Yes the electrical was upside down in the robot.

Above drawing, the wheels are actually staggered. The robot is a very fast robot and the work effort of the motors is very low. They are not fighting each other at all.

Above: A new design for our omni drive

Omni Drive, Fast, a lot of power (if with many wheels), rotates quick, can go any direction, programming can be a challenge, Must have a talented driver. If not designed perfect it is hard to control.

____________________________________________________________

omni track design

_________________________________________________________

Mecanum wheels

The Mecanum wheel is one design for a wheel which can move in any direction. It is sometimes called the Ilon wheel after its Swedish inventor, Bengt Ilon, who came up with the idea in 1973 when he was an engineer with the Swedish company Mecanum AB.

It is a conventional wheel with a series of rollers attached to its circumference, these rollers having an axis of rotation at 45° to the plane of the wheel in a plane parallel to the axis of rotation of the wheel. As well as moving forward and backward like conventional wheels, they allow sideways movement by spinning wheels on the front and rear axles in opposite directions.

Below: Wheels by Andy Mark. To view these and other omni wheels visit http://andymark.biz/

  We are currently using the standard four wheeled drive system but have omni wheels in the rear.  In this configuration the arm is located above the front solid wheels to make the axes turn at the arm so we can have more control of the claw. With the claw so close to the turn axes it does not move very far in a turn thus allowing for more control.

 Remember, any claw will work, it's how well you build it. (get the bugs out)

 The above Idea proposed by Pat Major of the Goodrich Martins allows for easy turning but stops other robots from spinning your robot so easily when hit from the front or rear side.

Standard  two wheel drive with casters. Easy to build and drive, can be fast.

        

Four wheel drive and Six wheel drive, takes a lot of power to turn so you will loose high speed unless you install a two speed gear system which can give you trouble if you don't get it perfect.

                          

Two wheel drives that rotate, casters in rear. Easy to drive , not bad to program. can go all directions including sideways. Limited traction, can be pushed sideways.

Four wheel drive that all wheels rotate together, the arm would have to rotate with the drives to make it work. Easy to program easy to drive, a lot of traction and stable. can go any direction. Good for many jobs. Click  IDEAS  for more information

            

Four wheel drive that all wheels rotate separate, you can go straight and angle or rotate. good traction, hard to set up, hard to program, hard to get the controls right for easy driving. Can go any direction including rotate.

Tank track, Tank track with drop down casters for turning. Can out push another robot but is limited on its speed. Even with two speeds it will not turn quick. Drop down caster will help but added engineering required.  Good for a specific job.

All drive:  All wheels across the bottom of the robot drive and rotate. An idea not solved but has a lot of potential. Click  IDEAS  for more information

Top of page

 

 

 

 

 

 

 

 

 

 

 

                            

FCA FOUNDATION

Home | Up | News | Robotics | Team Schedule | Resources | Community

 
Copyright 2007
Last updated: 06/26/15.