NXT Quad Drive Holomonic Platform

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I’ve been working on a new LEGO Mindstorms NXT Dual Drive, Quad Holomonic Platform. This Robot uses dual Rotacasters on each of the four axis’s. The Robot also uses four NXT Ultrasonic Sensor between each of the four axis’s. The four Ultrasonic Sensor work in ‘MODE 3: Event Capture Mode’. The Ultrasonic Sensor are cycled through one-at-a-time, to avoid interference between each of the sensors.
Holomonic Quad
Quad Drive Holomonic Platform with Power Functions<

I have built three versions of this Robot:

 Version One using Four Large Power Functions Motors too drive the 4 axis’s, controlled via the Power Functions Infra-red Protocol.

Quad Drive Holomonic Platform using Power Function Control via Mindstorms NXT
Quad Drive Holomonic Platform with Power Functions Control

Quad Drive Holomonic Platform CAD View Quad Drive Holomonic Platform CAD View
Quad Drive Holomonic Platform CAD View Quad Drive Holomonic Platform CAD View
Quad Drive Holomonic Platform CAD View Quad Drive Holomonic Platform CAD View

Quad Drive Holomonic Platform with Power Functions Control

Videos Coming Soon!

Version Two using Four Large Power Functions Motors too drive the 4 axis’s, controlled directly via the NXT Birck’s Motor Ports. Opposite Motors are paralleled to each other. One pair is connected to Motor Port ‘A’ and the other to Motor Port ‘C’. 


Quad Drive Holomonic Platform with NXT Controlled Power Functions Motors

Quad Drive Holomonic Platform with NXT Controlled NXT Motors Using Mindsensor NXTMMX Quad Drive Holomonic Platform with NXT Controlled NXT Motors Using Mindsensor NXTMMX
Quad Drive Holomonic Platform with NXT Controlled NXT Motors Using Mindsensor NXTMMX Quad Drive Holomonic Platform with NXT Controlled NXT Motors Using Mindsensor NXTMMX
Quad Drive Holomonic Platform with NXT Controlled NXT Motors Using Mindsensor NXTMMX Quad Drive Holomonic Platform with NXT Controlled NXT Motors Using Mindsensor NXTMMX

CAD of Quad Drive Holomonic Platform with NXT Controlled Power Functions Motors

Videos Coming Soon!

Version Three using Four NXT Motor’s. Three connected to the NXT Motor Ports, and the fourth is controlled via a NXTMMX. The NXTMMX’s ‘Sensor Daisy Cain Port’ is used to control the NXTMMX and a single Ultrasonic Sensor. You just have too love the NXTMMX’s design.


Quad Drive Holomonic Platform Using NXT & NXTMMX Controlled NXT Motors

CAD of Quad Drive Holomonic Platform using NXT & NXTMMX Controlled NXT Motors

Videos Coming Soon!

Notes Regarding the CAD Drawings:

The Red Wheels, in the CAD drawings need to be swapped for Rotacaster Omni-wheels for the Robot to work.

The Bright Pink, 16-tooth Gears need to be replaced with 24-tooth Technic Gears. Due to the difficulty of aligning ’24-tooth Technic Gears’, I decided it would be less frustrating on my behalf just to use the Bright Pink 16-tooth Gears.

 

Download the LEGO Digital Designer CAD Files:


If you wish to use Multiple Ultrasonic Sensors on your NXT Robot, you need to program them so only ONE Sensor is taking a measurement at any given time. If you have all the Ultrasonic Sensors on at once, they interfere with each other and give incorrect readings. To get around this you need to take advantage of the Sensors ‘Mode 3: Event Capture Mode‘. Refer to the Lego Mindstorms NXT Hardware Developer Kit: Appendix 7: LEGO MINDSTORMS NXT Ultrasonic Sensor I2C communication protocol.pdf for details.

Event Capture Mode:

NXC Source Code:

To use the Ultrasonic Sensor’s “Mode 3” with NXC, you need to use I2CWrite(PORTnumber, 0×41, 0×03) to turn on and initialise the sensor.  You can the then use SensorUS(PORTnumber) to read the distance to object. To turn the Sensor Off again, you need to use I2CWrite(PORTnumber, 0×41, 0×00). You need to repeat these commands for each Ultrasonic Sensor you are using. It pays to initialise all your Ultrasonic Sensors to the Off state when the program starts.

 

NXC Source Code:

(Large Power Function Motors paired & NXT Motor Port Control)

 

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