W.A.L.T.E.R.

Here is the cutest video I have of W.A.L.T.E.R.  It co-stars my kitty, Doozi.

The Robot and the Pussycat

8-Dale

73 from N7PKT!

Here are some older videos of W.A.L.T.E.R. 1.x - the earlier years. These are all 2 or 3 years old, but do show the various things I have experimented with so far.

Octabot 1.5 In Action, 1 of 3

Octabot 1.5 In Action, 2 of 3

Octabot 1.5 In Action, 3 of 3

Scanning Behavior 101a

8-Dale

73 from N7PKT!

I've been working on a change that will get the wheels up closer to the lower deck. This will also allow me to strengthen the link where the steering servo attaches. I have not been happy with this link, which wobbles quite a bit. I've got a method to strengthen the link, which is borrowed from the Lynxmotion Scout where the hip rotate servo attaches to the body. I'll have to relocate the sensors I was planning to mount above the wheel steering servo, but have also resolved this. I will just mount those sensors a little bit forward from the location of the front steering servos. These changes will make WALTER much sturdier and and more stable.

8-Dale

73 from N7PKT!

Here is an update on my progress with WALTER.

Here you see the BotBoard II with the Atom Pro MCU module. The Atom Pro runs at 16 MHz and has 20 I/Os, all of which are dedicated to WALTER. The PS2 wirless receiver is on the right. I just have the four steering servos and PS2 receiver connected at this time, but there will be more.

This is the Sabertooth 2X5 Regenerative motor controller. It has several modes of control, including standard PWM, Simple Serial, and Packet Serial. I've used the PWM mode, which is controlled just like two standard R/C servos, but will be using the Packet Serial mode this time around. I'll eventually be replacing the Sabertooth with Basic Micro's RoboClaw 2X5A controllers because the RoboClaw has built in quadrature decoders.  I've got QME-01 quadrature encoders on WALTER's GHM-04 rear motors and will also have encoders on the front motors, so will be using two RoboClaws for motor control.

Here, I've attached all the necessary wires to the Sabertooth 2X5 motor controller. The twisted yellow/orange wires go to the motors and the wires out the top go to the BotBoard II (pin 15). I always use a wiring harness for power that has a switch.

This is the PS2 Wireless Robot Controller I have been tinkering with.

Another shot showing the BotBoard II/Atom Pro, PS2 wireless receiver, and Sabertooth 2X5 motor controller, and new pan/tilt for the two front sensors.

WALTER and my ICOM IC-706mIIg all band/all mode tranceiver. He can't talk yet, but that might be in his future. I am planning to install a small packet (or other digital mode) station on WALTER eventually.

8-Dale

73 from N7PKT!

Today, I am working on getting WALTER's motors going.  I've got all the necessary wires plugged into the Sabertooth 2X5 motor controller now and am ready to connect a battery and the motors to the controller. This time around, after I have the motors connected the way I need them, I am going to solder the motor wires to the motor rather than use the push on connectors.  Those connectors always keep coming off, which is not a good thing at all. I also have to add noise suppression capacitors to the motors to reduce noise that might get into the electronics. I don't really think I will have noise problems though, since all the electronics is on the second deck, and the motors are under the main deck.

I also have the PS2 wireless game controller wired in and have been working with it and learning how to utilize the analog sticks and buttons. I can read all the buttons perfectly, and have the triangle button setup to toggle between autonomous (WALTER roams around unattended) and remote control (I control WALTER). Right now, I am trying to control the front pan/tilt sensor platform on WALTER using the left analog stick - this works excrpt the stick does not automatically center when I release it. I'm still working on figuring this out. I also have a tentative design for a two stick control system to control all four wheels on WALTER, which have independent steering and speed control.

Now, I need to charge up some batteries.  WALTER will have three NiMH batteries - one for the electronics, one for the motors, and one for servos.

Pictures will follow!

8-Dale

73 from N7PKT!

After a hiatus of a few months due to health issues, I am back working on W.A.L.T.E.R. I am turning WALTER into a 2WD/4WD robot with independent steering on all wheels.

I have all the parts, but have decided to go with different wheels.  I need a 1/6" hex wrench for the set screws of the Banebot wheels, and have not been able to find one yet.  I always thought allen wrenches and hex wrenches were the same, but this is not true. In fact, it seems like several very different tools are calle hex wrenches. At any rate, I have found some wheels I like better, which will work with the Lynxmotion HUB-12 12mm hex hub. In fact, I have found several different wheels that will work with this hub and know there are even more out there, which gives me a wide choice of tread and wheel diameter.

I've also shot several pictures of WALTER which can be found at my PhotoBucket account.

Eventually, I want to turn WALTER into a true hybrid (walking and rolling) robot, but this will require much heftier servos than I have been using, so that will be delayed. In the meantime, I have decided to turn ASTRID into a quadrapod four legged walker using a custom SES leg I have designed. I have already built one of the legs and it looks very promising! I will be putting some pictures of ASTRID online soon!

8-Dale

I've been doing some tinkering with hybrid leg/wheel designs and built up a 5 joint leg with a steerable wheel attached at the end. I was looking at the completed assembly and was wondering how I could check it out and work with it. I did some rough mechanical alignment of the five servos according to how I want the assembly to move and the maximum ranges for each joint.

Since the only robot body I have that is large enough to support this leg is WALTER, I attached it to his body. I was amazed at how this hybrid leg looks on WALTER. His body is plently light enough with three decks that I think four of these legs will work fine to move him around, even with batteries and electronics installed. Since there are going to be four steerable wheels powered by gear head motors, I'll have to use two Sabertooth 2X5 motor controllers because it won't work to pair the motors up on a heavier duty controller. With each wheel being steerable, I need independent control of all the motors.

I'll definitely be using an SSC-32 servo controller to handle the hybrid legs. With five servos per leg and four motors, it will take up to 24 servo ports on the SSC-32 if I use PWM to control the motor controllers. With this new hybrid leg design, it may be possible for WALTER to adjust to terrain and maybe even do a bit of climbing.

8-Dale

73 from N7PKT

I will add a wireless communication system to WALTER also, which will consist of WiFi-G and ZigBee. The AXON controller has three available UARTs (TTL logic level serial ports), so one will connect with a ZigBee wireless module, and another one will connect to a WiFi-G module. I'll be getting a ZigBee module (with this adapter) from Sparkfun and may get the WiFi-G module there also. This would leave one UART available for other things. I am not sure if I will need an SSC-32 now, since I've decided to remove the arm.

I'm still researching the WiFi-G to see what is available that might work best on WALTER. With this, there would be the possibility have allowing internet users to control WALTER in a limited way. With ZigBee, the area of swarm research will be opened, and WALTER will have the capability of communicating with other robots, like ASTRID.  I'll be putting the same communication system on ASTRID after she is up and running.

This will be the last complete rebuild I do with WALTER.

8-Dale

73 from N7PKT

I've been working on the new decks for W.A.L.T.E.R., and have them almost done now. I have created 3 new decks, and assembled them into a new 3D CAD model. So far, everything is looking pretty good and I am almost ready to make a test run and have somebody create them. I just need to find somebody who has a CNC machine that can accept data from a DXF file and create parts 11 1/2" in diameter. I don't want to spend too much money on a trial run of making the new decks.

I originally designed W.A.L.T.E.R. to have four decks.  However, I may stay with a three deck setup since I have decided to focus his development on just a few specific areas.

8-Dale

73 from N7PKT

After thinking about what I am trying to do with WALTER, and robotics in general, I've decided to remove the pan/tilt from the bottom deck and remove the arm from the top deck. I think I've been trying to do way too much with WALTER, and am going to orient him only to three specific areas now. Doing this will allow me to use both of the nice ball casters I recently purchased for him and solve the last mechanical problem I've been working on. I've been real unhappy with the placement of the new casters on the bottom deck due to the location of the pan/tilt.

From now on, I will orient WALTER completely for line following, maze solving, sensor experimentation, swarm research (with ASTRID), and behavior based robotics. With the AXON controller, I have the processing power and potential to do some really cool and interesting stuff in these areas. I think this will be the perfect fit for WALTER. I'm getting a Tracker sensor that I'll mount at the front of the bottom deck for line following.

This will be the last complete rebuild I do with WALTER.

8-Dale

73 from N7PKT

W.A.L.T.E.R. is now officially in pieces.  Many pieces!  Today I am connecting and testing the new electronics that will serve as the main control section.  I've resolved the power connection issues I had and will be routing all power from the SSC-32 servo controller instead of from the AXON controller. This is mainly because the AXON doesn't have power connections that are compatible with the battery packs I have. I'll have the SSC-32 setup with the VL=VS1 jumper installed and the VS1=VS2 jumpers removed. This allows me to power all the electronics from the VL/VS1 battery pack (7.2V@2800mAH NiMH) and use a 6V@2800maH battery pack for the VS2 supply which will power the servos.

I am looking at the possibility of using a RoboDuino (an Arduino compatible board designed for robotics) to handle reading several PING ultrasonic and a few Sharp IR range sensors, plus maybe the front pan/tilt where a pair of sensors will be mounted.

I'll adjust the spacers between the bottom and second decks to accomodate the new pan/tilt sensor base. The pan/tilt is already assembled and has a PING sensor on it.  I just have to add a Sharp IR sensor to that and mount everything to the bottom deck. I will move the batteries up to the second deck to put them right in between where the AXON/SSC-32 (third deck) and motor controller (bottom deck) are. This should make routing the power cables easier.

Today's main project is connecting power to the SSC-32 and routing power to the AXON so I can start tinkering with code. I seem to have misplaced my motor controller, so I have to find that also. The motor controller and motors will be powered from the 7.2V@2800maH battery that also powers the rest of the electronics and most sensors. With this setup and powering servos from a separate 6V@2800mAH battery, I should get a reasonable run time with W.A.L.T.E.R.

8-Dale

73 from N7PKT!

I've started working on the new control code for W.A.L.T.E.R., in anticipation of receiving the new Axon controller this coming week. I want to be able to start tinkering with the AXON as soon as it arrives. The first part of the code I am working on is what is required to read the PING Ultrasonic and Sharp GP2D12 IR sensors I have.  These will be the workhorses of W.A.L.T.E.R.'s sensory perception. I like to mount these as a pair because what one doesn't see, the other one usually will. This pairing increases the chances that W.A.L.T.E.R. will see an obstacle.

Since the existing routine for processing the PING doesn't do things quite the way I want to do it, I have cloned the existing routine and renamed it so I can modify it to do things my way. I will eventually mount several of the PING sensors in various locations around the body and want to be able to process them all inside a loop. If this works out as I hope, I'll create a routine for the GP2D12 that processes them in the same way.

One pair of sensors will be on a front mounted pan/tilt base, which will allow for coverage of the area in front of and slightly to either side of center that isn't covered by the sensors on the sides of the robot. It will also allow seeing down, which I hope will help keep W.A.L.T.E.R. from falling down stairs and off cliffs.

Once I have completed the sensor processing code for the PING and GP2D12, I will be able to move on to writing motor control code for the Sabertooth 2X5 that controls the two GHM-4 gear motors that move W.A.L.T.E.R. around. Once this is completed, I'll have all the basics for W.A.L.T.E.R. and can move on to working on actual behavior code that will control how he sees and interacts with his environment.

8-Dale

73 from N7PKT

I finally did it!

I've selected and ordered the first of what will be several controller boards for W.A.L.T.E.R. I've been looking at the Axon controller for awhile now, but jave not purchased anything due to there being so many good controllers available. I am extremely picky about controller features due to some not so good experiences in the past. However, the Axon does have the features I need for W.A.L.T.E.R., at least for now, and can be used as an auxilliary controller in the future when I decide what I want to use for the on board Linux based main controller. For the time being, after I get a bluetooth tranceiver for the Axon, my main Windows/Linux PC will be the main controller.

Essentially, the Axon will be the main controller for W.A.L.T.E.R. for now as I learn to program it and use all of its features to the fullest. The Axon is programmed in the 'C'/C++ language, which is a major requirement. I'm through using proprietary hardware that requires me to be at the mercy of the company who makes a controller, their proprietary development system, and proprietary programming language! From now on,  I require 100% Open Source and standard development tools for W.A.L.T.E.R. and any other robot I may build in the future. My main programming language on the main controller, whatever it ends up being, will be Python, which is also 100% Open Source as well as platform independent. Python is available for Windows as well as Linux, UNIX, and most other operating systems.

The only other type of controller I would consider is one that has its development system integrated into the board itself, such as the ServoPod.  This is definitely another controller I want to work with in the future.

My next step is to get a few pictures of W.A.L.T.E.R. in his current disassembled state and get them online here or on a Wiki, to start tracking my progress for version 2.0. I'm quite excited about being able to actually start working on everything for W.A.L.T.E.R. v2.0 now!

8-Dale

73 from N7PKT

OK, it's time to stop thinking about what I want to do with W.A.L.T.E.R. and start doing something about it! I have him down on my work table, got Python installed, and am ready to start getting back to making things happen. I have a lot of rewiring to do to get ready to make W.A.L.T.E.R. operational again, and he still needs a new brain, but I am getting closer to seeing him roll around again. Python is an interpreted programming language that is great for many things, including scripting and prototyping of applications. I like to use it as a control language because changes can be made and the results seen right away. I hope to use Python as the main programming language for W.A.L.T.E.R.'s software.

I still don't know what I am going to do about casters for him, because there aren't any stock casters that will work properly. Ideally, I would like to use two omni-wheel casters, one on the back and one on the front, but this would require some custom design and machining which I am not able to do. Well, I can do the designing that would be required, but my PC isn't currently up to running my 3D CAD software at this time. That would still leave the machining. I'd want an adjustable design that would allow the casters to be made the proper height and allow that to be changed if I use different sized wheels or otherwise affect the height the casters would need to be at.

I'm definitely convinced the way to go for processing power on W.A.L.T.E.R. is to have one master processor with a lot of power that has several smaller processors for given functions, such as sensor processing. One processor might even be assigned to a single sensor, depending on the sensor's complexity. I'll be tinkering with Arduinos and Sanguinos for at least some of these tasks, and I have one of each here now. There is also the onboard arm which will require dedicated sensor and movement processing. I'd like to mount a small camera on the end of the arm near the gripper.

For now, I have some untrasonic (sonar) and infrared sensors, as well as an accelerometer and digital compass. I want to eventually get a GPS unit for W.A.L.T.E.R. when he ventures outdoors. I have quite a bit of stuff to tinker with right now and it will take some serious time to integrate everything. I'm planning to pair an IR sensor and an ultrasonic sensor, which should give the best chance of "seeing" any object for distance detection.  If one sensor misses something, the other one will usually "see" it.

I'm going to be changing the deck setup for W.A.L.T.E.R. I've designed a new pan/tilt unit that I'll mount on the front which will have a +/- 60 degree range of motion horizontally and +60 degree and -90 degree vertical motion. This will allow W.A.L.T.E.R. to "see" with a very wide range. There's also going to be two pair of sensors (IR and ultrasonic together) mounted fixed that will point off to the sides about 30 degrees either side of center. Beyond that and the accelerometer for tilt and speed, compass for course, plus eventual GPS, I only want to add a thermopile (heat) sensor for detection of warm bodies (like my cat and Humans).

Well, that's my story and I am hoping I can stick to it!

8-Dale. 73 from N7PKT.