Let's Make Robots!

Rover 5 tracked robot chassis with adjustable clearance


AttachmentSize
Chassis_size.jpg195.69 KB
Rover5_Arduino.zip4.11 KB
Vendor's Description: 


Rover 5 is a unique and powerful  tracked chassis designed by OddBot and produced by DAGU.

Specifications:

Motor rated voltage: 7.2V
Motor stall current: 2.5A
Output shaft stall torque: 10Kg/cm
Gearbox ratio: 86.8:1
Speed: 1Km/hr
Encoder type: Quadrature
Encoder resolution: 1000 state changes per 3 wheel rotations

Tips on using the encoders with sample code can be found here: http://letsmakerobots.com/node/24031

Video indoors autonomous: http://v.youku.com/v_show/id_XMjE5NzkwODA0.html
Video outdoors RC mode: http://v.youku.com/v_show/id_XMjIwMTkxODk2.html
Video mecanum wheels:  http://v.youku.com/v_show/id_XMjI2MDAwMDEy.html

Unlike conventional tracked chassis's you can adjust the clearance. Strechy rubber treads maintain tension as the clearance is changed.

The standard chassis comes with two motors and gearboxes. Each gearbox has an optical quadrature encoder with a resolution of 1000 state changes per 3 revolutions of the output shaft (333.33 pulses per revolution).

The chassis can be upgraded to 4 motors and gearboxes with encoders making it ideal for mecanum wheels such as those produced by FINGERTECH.

The chassis is compatible with Pololu's expansion plates for the RP5 chassis. These plates are ideal for mounting hardware on the chassis.

The gearbox angle can be changed in 5 degree increments and adaptors are available allowing standard RC car wheels to be fitted.

Currently we have a PCB designed to allow Arduino development boards (not included) Diecimila, Duemilanove, Nano and Mega to mount easily on the chassis. This PCB includes power supply, motor drivers with current sensing, IR sensors on each corner, 2 small breadboards, a pan/tilt kit with our IR compound eye and a large prototype area under the breadboards where custom circuitry can be fitted.

The photo below and video show the robot using an Arduino Mega which is not part of the kit.

See the attachments for basic dimensions and autonomous sample code.

 

 

 

 

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Hi.

2 weeks ago, i bought this rover 5 with 4 motors and 4 encoders from local store in Indonesia. And i just had figure it out when i open the gearbox and find out the gear has no black and white pattern just like figure on datasheet pdf rover 5 tank.

Is it has no black and white pattern and personaly adding needed? Or it was factory issue?  And what a 4 black tube is in the center of the platform is sir? Is that a fuse ? os some like a noise filter?

I'm sorry if my english not so good sir.

 

Thanks

 

Only the old Rover 5 chassis's had optical encoders that needed the black and white pattern. The new encoders are all magnetic and use an 8-pole disc magnet stuck to the gear.

The 4 black tubes are inductors to help reduce electrical noise from the motors.

Is the magnetic encoder has the same resolution with the optical one sir? And is it ok if the gear has ever been removed? i mean, is there a zero position thing of this gear? I was trying to connected signal A to external interrupt pin microcontroller and signal B to and ordiinary input pin microcontroller. If the signal B had a logic 1, counter up and if 0 then counter down. And the result, i got 86 counter in 1 wheel rotation. How to use it sir? I think the manual of this rover 5 need to be updated whit a new one sir. Thanks

Oddbot has mentioned elsewhere the magnetic encoders have the same resolution as the optical encoders.

Your 86 is pretty close to the 83.3 full cycles one would expect from the encoders. Oddbot has a tutorial here on how to use quadrature encoders.

From what I've read, I think most Arduinos aren't fast enough to capture all the quadrature encoder interrupts and still have time to perform other tasks. I believe reading all four quadrature encoders requires a fast microcontroller. I used a Propeller in both of my Rover 5 projects.

Here's a link to my Rover 5 with treads. Here's my Mecanum wheeled Rover 5 project.

The arduino running at 16 MHz (the normal speed) processes close to 16 million instructions per second.  At 180 RPM on each wheel, using all four encoders, and the motors turning 180 RPM, there would be a total of right at 1000 interrupts per second.  With each interrupt taking about 20 instruction cycles, that would be 20000 out of 16000000 each second, or 00.125% of the total processing cycles available.  That amount is negligible.  Even horrible code that took 100 times longer would still leave over 87% of the processing cycles for other things.

Thank you very much for your reply. I'm very curious about this myself. Rather than hijack this thread, I started a forum thread to expand on what you told me.

You may have just saved me from a lot of unneeded work.

oops... sorry double post

Oddbot,

I foolishly snapped a gear... do you know where I can purchase a replacement?  Anywhere in the world?

It was only foolish if you had no fun in the process.

Unfortunately there are no shops I know of that stock spare parts. Your best bet is to email Claudia at DAGU and request some replacement parts. Might be worth ordering a few extras as the postage will be higher than the cost of the part.

thank you!  she was very helpful!