Archive for the ‘Urban Challenge 2007’ Category

Alternator busted; replaced in an hour

Monday, October 29th, 2007

October 29, 2007 (2330 hrs), VICTORVILLE, CA.   I thought I’d never face this again after retiring CajunBot (I). I thought all the emergencies due to mechanical failures were history. Turns out I was wrong.Around 1800 hrs I got a call from Little J. that the Jeep was not cranking. We got Joshua out of the bed and rushed him. He diagnosed that one of the alternators was busted. CajunBot has two alternators, one added after market by a alternator-holic in Alexandria, LA. One of the alternator is bought from Autozone and the other from High-Output Alternators ( The latter is a speciality product.

By 1830 hrs Joshua, Adrian, Dallas, and Scott were headed to the pit, which is where our trailer is parked. The trailer, thanks to our contingency planning, held a spare alternator, the high-output one. By 1900 hrs, the broken alternator, which happens to be the high-output one, was replaced. Joshua has messed with these alternators for so long, he says he can change them in his sleep. Which is good, for the next three days I expect him to be walking in his sleep anyway.

Well then again, may be I was not wrong. The mechanical failure did not create any sense of emergency in the old-timers. I never stepped out of the hotel. The software guys stayed focused on their work. We were pretty confident that this shall also pass.

I have placed order for another HO alternator, just in case there is another failure in the next five days.

– Arun Lakhotia

Day 3 performance, thumbs down

Monday, October 29th, 2007

October 29, 2007 (1322 hrs), VICTORVILLE, CA – Our Day 3 performance was not really good, but we knew the issues going in. We still need to take care of a few things, before we’d be ready for passing this test.

In this test, held in Area B, the bot is expected to get out of a start chute, navigate an open space, go through a narrow winding lane bounded by massive K-rails, drive around a traffic circle, and then drive into a very convoluted neighborhood. We do not know what all goes in the neighborhood, but the general guess is that it has stalled vehicles parked on the side of the roads. The bot needs to safely travel through that area, avoiding rear ending any vehicle.  In this area is a parking lot. The bot has to find a designated parking spot, not run into vehicles parked into adjacent lanes, and then get out of the parking lot. Finally, in the area is an ‘obstacle zone.’ This is an open space, with barricades forming a gate. The vehicle has to find the gate and go through it.

CajunBot had trouble right out of the start chute. It was stumped by all the K-rails along the border of the open area, and decided not to budge. After two unsuccessful attempts, Suresh did some quick thinking and made some changes. That made CajunBot, go past the initial hesitation, travel through the winding lane, and onto the traffic circle.

Just short of completing the traffic circle, CajunBot came to a stop. For a few minutes you could see her attempting to take off, but stopping again. The trouble shooting team, consisting of Mark and Suresh, were rushed to the site. They attempted a few things, but nothing helped. By then we were out of our alloted 40 minutes.

The good news is DARPA announced a second round of tests in the remaining 2.5 days (Monday PM to Wednesday PM). Earlier they had announced the schedule only through Monday AM. We expected that after the first round of tests in the three areas, some teams will be selected as having passed the tests, and others will be given another go. It turns out all the teams are scheduled to run in the second round of tests. I can infer that to mean that there is clearly no perfect performer.

Inspite of all the long hours, the team is holding up well. Everyone is stretched to the limits, but no one is cracking. There are no outbursts, or name callings, or “I want my mommy” calls.

The clock is still on, and we intend to keep hustling.

– Arun Lakhotia

Angels driving the bot

Monday, October 29th, 2007

October 29, 2007 (0010 hrs), VICTORVILLE, CA. If you do not believe in angels, this should make you a convert. After looking at the data from Area A test we are completely stumped why CajunBot did not ram into the traffic vehicles. She came quite close to running over some of the cars. But she always stopped, just short.Here is a video of the test run on YouTube

Looking from outside, she looked like just an aggressive driver with little respect for other drivers. But cautious enough to brake at the right time.

But having looked through the data, it comes as a surprise that she avoided any vehicle at all. While she did not have a human driver, she sure looks she was bring driven by an angel.

Christopher Mire, the unassuming and quiet graduate student on the team, patiently trudged through the loads and loads of data collected by CajunBot, looking for an explanation for her aggressive behavior. His conclusion the vehicle was running WITHOUT its primary sensors, the Ibeo and SICK lidars. The physical sensors themselves were working, but our program that analyzes the sensor data to identify objects in the world had crashed. And by crashed it means, the program was not running. The sensors were generating data, but there was no program using the data. For most practical purposes, CajunBot was running blind.

CajunBot was running on her secondary sensors, the radars, two of which were acquired and mounted after we came to Victorville, CA.

It just cannot be a happenstance that we acquired two radars after arriving in Victorville, CA and those lidars save the bot from total destruction. There must be an angel watching over CajunBot.

Christopher has diagnosed the reason for the crash. When we run the bot in Cajun Field, a wide open parking lot, CajunBot sees a very few (between 50 and 100) objects. Our obstacle detection and tracking system was configured to track 100 obstacles. But in the test area, an abandoned air base, there is a lot of clutter, The area has buildings, trees, bushes, and other traffic. As a result the sensors see about 500 obstacles. This exceeds the max limit of 100 programmed into the system, and our obstacle detection program simply crashes.

The fix for this problem is rather simple, and has now been taken care of.

– Arun Lakhotia

Day 2 – A fantastic turn around

Sunday, October 28th, 2007

October 28, 2007 (1533 hrs), VICTORVILLE, CA. — CajunBot went through the test of fire, and came out looking real good. Its been a great 36 hrs day for many, in particular, Little John, and now he is too excited to fall asleep.The test in Area A is plain and simple scary. The track consists of a two lane (one each way) rectangular road, about 120m long and 40m wide. Across the middle of the long segment, top to bottom, runs a one lane road.

The test setup consists of 10 (may be more) cars making laps around the course, five in the inside loop and five in the outside loop.

CajunBot (as are other vehicles) is given the mission to loop around as well, but she does not travel the full rectangle. Instead she is supposed cut across the rectangle, along the one lane road.

The vehicles in the outer loop have the right of way.

The test requirement is that when CajunBot turns left from the outerloop to the one lane segment, she has to yield to the traffic in the oncoming lane. When she makes the next left turn from the one lane segment to the outer loop, she has to yield to the traffic coming from the left and the right.

The traffic flows around 8 to 12 miles/hour.

The traffic vehicles is manned by race car drivers. They are driving specially built with amazing amount of reinforcement. The drivers too are in full race-car regalia, with helmets and suites designed for race car driving.

The evaluation is based on number of loops completed in the 40 minutes alloted, the number of loops made without any safety error. There is penalty for making the other drivers honk. There is also a penalty for taking too long to merge into traffic.

I forget the number of loops CajunBot did, but it was in double digits (around 15, or more). Over six of those loops were flawless. (I didn’t keep track of the count. The experience was too gut wrenching to worry about counting loops.)

The grapevine has it that our performance is amongst the top quartile.

The team is very upbeat, and feeling really good about the accomplishments. If only you knew how hard this team has worked every single day since arriving in California you’d not believe it.

I am so glad that Adrian “Fatty” Aucoin is here. After retiring CajunBot (the mama), we had thought we’d never have to haul a bot in a trailer. We sure were wrong. We really do not want to be driving a $2MM car in normal traffic. One fender bender, and we’d be history. So we have rented a flat bed car hauler. Fatty is a pro in hauling the trailer. He also serves as one of the drivers during traffic tests.

Besides renting a car hauler, we have rented another RV, a small one. This will serve as a ‘nap mobile’ for the team, especially useful when the team is working in the field. It came in real handy last night. I got to take a nap in it at from 0400 to 0600 (hrs).

Tomorrow we test in Area B. This is the longest test, and has some really interesting situations. Tonight will be another long night.

After today’s performance, we have a chance to be back in the running for the final. Tomorrow’s test is very crucial.

I need to run to a team meeting. After the meeting several members will go to bed, and others will head to work.

– Arun Lakhotia

Someone — send my little daughter a card

Sunday, October 28th, 2007

October 28, 2007 (2009 hrs), VICTORVILLE, CA.  Took a three hour sleep. I am really glad Scott Wilson, my “lets go, lets go, lets go” guy is here. He has taken charge of the drum beat for the team. And he beats really fast.I woke up and realized I had not talked to my little daughter Manjistha in three days. She is six years old. Last I talked she said, “Daddy you shouldn’t have gone on this stupid trip.” She had wanted to come with me, and I knew there is no way I could be attending to her as well.

Every day she likes going to the mail box, the real physical mailbox, looking for mail. Most of the mails she gets are Disney magazine and brochures. Every now and then she gets a birthday invitation. Any mail with her name on it causes a big excitement for her.

I have been meaning to send her cards. But the eight days I have been here are a blur. I have not yet sent her a card.

I’d like to appeal to send her a card. You could send it to my office address, and it will get delivered to my home.

My office address is on the following website:

(Rochelle: Should you receive any mail, please pass them on to Enam. Given the open nature of this blog, I may be putting my daughter at risk if I put my home address on the website.)

– Arun Lakhotia

Day 1 didn’t go as well….

Sunday, October 28th, 2007

October 28, 2007 (0933 hrs), VICTORVILLE, CA.  — You’ve not heard from me in 24 hrs, and I am sure you guessed that cannot be good news. Our performance in Test Area C was sub par. CajunBot goofed up on things we have tested over and over again, and didn’t complete one task we knew she may have difficulty.

The moment we finished (rather, did not finish) the test, we went into a huddle. Analyzed the reasons, and then started focusing on the next test today in Area A. This one is going to be a killer. Almost everyone has been working through the night. That makes it two nights barely with any sleep for several members — Pablo, Suresh, Mark, John, Chandan, and Dallas.

Here is a quick summary of what happened in Test Area C. The area is a ring with two 4-way stops (intersections) on opposite end. The bot is expected to go around the ring, and at each 4-way stop she is met with other traffic vehicles. She has to maintain the rules of a ‘stop’ sign, give precedence to other vehicles that come before it.

This capability was tested  few months ago in the site visit, and we test it routinely.

CajunBot did well for the first two interactions at the stops. In the third interaction, there were three vehicles already at the intersection. She let two vehicles go, but then took before the third vehicle moved. This was a complete surprise to us.

After that the behavior kept getting worse. A similar scenario was created in the next stop. This time CajunBot almost kissed the bumper of the car ahead. In the next loop, she was riding the curb and didn’t care of any other vehicle at the stop sign. You kind of get a feeling she was irritated to be given such stupid test.

As the loop progressed she was to encounter a blockage in the road and expected to turn around. This is also something she has done many times. But this time around, she just went stopped in front of the blockage and decided not to move.

That was the end of the test, for the bot would not progress any further.

What caused this misbehavior? Our analysis indicates two things: first, it looks like after two loops the bot began experiencing a GPS drift, which essentially means she was shifting the middle of the road about two feet to the right (in some situations). That made her ride the curb. Second, we have never tested in a situation like this before. All our tests are in wide open spaces. This is the first time we are testing in a real neighborhood. The main difference now is that our sensors pick up a lot, lot more data in this environment. In the process something has tripped.

More on this later… I need to rush out to the test area.

– Arun Lakhotia

Get to know the NQE test area

Saturday, October 27th, 2007

VICTORVILLE, CA. — The NQE start today. Since you are following the challenge, you may be interested in the knowing about the physical location.As a starter, locate us on Google Maps. Click on View Map or search for ‘Starfighter Lane, Victorville, CA.’ The ‘arrow’ on the map points to the ‘start chute’ location for the finals of the challenge.

This area is now called ‘Southern California Logistics Agency.’ It used to be George Air Force Base. All that remains in this base are some empty buildings and an elementary school. Since no one really lives here, I wonder how this school gets kids.

Here is an aerial image of the Test Area A. (Click on the image to see a bigger picture.)

The test area is created in an abadoned parking lot. The yellow lines on the map show the DARPA map given to us. This track will be used for testing the ability of the bot to merge in traffic. The area consists of a rectangle with two way traffic, and a path cutting through the rectangle. During the tests, vehicles operated by DARPA drivers will be doing laps on the rectangle. The bot is expected to arrive at the intersections, and wait for other vehicle before merging in the traffic.

The following is an aerial image of Test Area B.

Area B looks the most complicated. It will be used to test the bot’s ability to drive even if the map given by DARPA does not have enough data points, the ability to park and unpark, the ability to drive through open space while avoiding obstacles.

Finally, the aerial image of Test Area C.

This area will be used for the bot’s ability to re-route it planned path if it comes across a blocked road.

Today we test in Area C, then in Area A on Sunday, and in Area C on Monday.

– Arun Lakhotia

Day 1 – Acitivities picking up

Saturday, October 27th, 2007

October 27, 2007 (0738 hrs), VICTORVILLE, CA.Day 1 activities are picking up. Most members of the team have been working through the night. Yesterdays licking in E-stop test served a purpose. The first timers have gotten a taste of what to expect in the next few days. The overall energy level is high.

Pablo Mejia, our Chief Architect, arrived last night. His presence changes the dynamics of the team. He has earned respect of everyone by his sharp mind, shooting from the hip simple solutions to difficult problems, and staying calm like a rock even in turbulence.

Pablo and crew have worked through the night. We have had a to close a lot of loose ends, issues we have known, but have not had time to attend.

At 0850 we have a practice run scheduled. We get a 40 minute slot in a wide open, dirt area. But for the bot, nothing else is allowed in this area. Which means we cannot really test some of the advanced capabilities in this area. However, our plan is to test the system’s ability to run for the whole duration. This will be a test of the electronics of the system. We experienced an electrical interference yesterday during E-stop test. Need to test whether similar issue may arise after the machine has been running (with all systems on) for a long duration.

The NQE test starts at 1220. We are the first in the group, followed by Stanford.

My role today is to wait on the team members. Joshua, Chandan, and Mark slept at 0430. I am not sure if Pablo slept at all. Suresh slept early, but woke up at 0100. They will be tired when they wake up. My role is to drive them to pit, power them up with coffee, and cater breakfast.

Quite coincidentally this hotel is owned by an immigrant of Indian descent. This guy has been great, serving me ‘chai’ every morning. So, my first stop out of my room is to go to his office and get my chai.

Time to shutdown the machine and roll.

– Arun Lakhotia

Broadpoint satellite brings Internet to Team CajunBot pit

Friday, October 26th, 2007

VICTORVILLE, CA. — If you are eager to follow the happenings in the challenge, you got to thank Mark LaGrone and Danny Burgess of Broadpoint. Thanks to them I am sitting comfortably in a motorhome in our pit and writing this note. I hope to bring you daily events as soon as they happen.Broadpoint has provided us with a satellite dish and subscription to the Internet service. The day before the bot left Lafayette I called Mark, my former student and neighbor, requesting a satellite hookup. Next morning 8:00am it was all ready to be picked up, with tech support instructions and all.

I was surprised how nice and compact the whole package was. Just three pieces. A satellite dish, a big suitcase with all the electronics, and a cardboard box with stand for the antenna. All I had to acquire on this side was sandbags to hold the base down.

Setting up the satellite dish was easy too. At least Dallas made it look easy. He is another multifaceted person. A computer science major, who is part of a rock band, does house renovation, great with logistics, and can climb up the RV to setup satellite dish.

While getting the dish setup on the roof of a RV is physically challenging task, for someone like me, the big work in setting up the dish is pointing it to the right satellite and setting up the correct orientations. Thanks to Broadpoints technology this was a breeze. Mark has given us an instrument called Birddog. With this instrument, you just punch in a few numbers, and it does all the work needed to talk to the satellite.

Isn’t that great. Another Ragin’Cajuns supporter stepping up to the plate to give a little helping hand to Team CajunBot.

Judice Middle students – I have read your comments on the blog. You can EARN T-Shirts, CajunBot visit to the school, and even an invitation to CajunBot’s homecoming celebration. All you need to do is find some creative way to thank my sponsors (individuals and companies that have helped my team).

Lets start with Broadpoint. Show me what you can do to make them proud of supporting us. I have other sponsors too. So get started fast. I’d be reeling out other names once I see your spirit. You help me with appreciating the sponsors, and you can earn a visit to Cajunbot’s homecoming on November 8th.

In case you need it, Broadpoint’s address is  113 N. Pat St., Scott, LA 70583.

The above offer is open to students of other Lafayette area schools as well. Please don’t mind my bias towards Judice Middle. My wife works there, and I couldn’t have done what I am doing without her support.

– Arun Lakhotia

Started off on the wrong foot

Friday, October 26th, 2007

VICTORVILLE, CA.    Through these reports, I want you (the reader) to experience what we are experiencing.  This means sharing with you the excitements of our successes and pain of our failures. Today, I have to share a pain.Today was supposed to be an uninteresting day. Start with opening ceremony at 0700. Then go for ‘safety testing’ at 1030. We have gone through safety testing so many times that it was expected to be a mechanical step.

Turns out that things did not go as smoothly as expected. We exhausted our alloted 30 minutes, and would need to do the test again.

Lets start with the basics of the capability being tested. The robots are autonomous, they drive by themselves. But you’d not want a car to go beserk. So DARPA has provided us with an ‘E-stop’, a wireless equipment. The receiver is setup on the bot. The transmitter is held by the DARPA operator. The E-stop has two buttons: DISABLE and PAUSE/RUN.

Before starting the bot, the operator presses the PAUSE button. Then the bot is given command to launch. The operator than releases PAUSE (and changes to RUN). The bot can now move. The operator may press PAUSE at anytime, and the bot must come stop. When the PAUSE is released, the bot may move. However, if the operator deems the bot to be getting dangerous, s/he may press DISABLE. At which point the bot must turn off the engine and never start again even if its put in RUN mode.

The E-stop safety test is intended to test this capability. If the bot behave as described above, it cannot proceed to any other tests.

The E-stop safety test proceeds as follows. We are given a ‘E-stop Test RNDF’, which essentially has a straightline path with two waypoints. The bot is placed on the first waypoint, the operator presses PAUSE, we are asked to give bot the command to go to the second waypoint, the operator releases PAUSE (changing to RUN mode), the bot begins to move, the operator presses DISABLE.

Nothing to it, we went through these steps for the DARPA site visit in June.

But, sometimes its the simple things that can bite you. In the above sequence when the operator pressed released PAUSE, the bot would not move. When the bot goes autonomous she is expected to turn on its emergency (flashing) lights and the siren. This time she was completely quiet. Not a beep and not lights.

The launch team, consisting of Joshua, Suresh, and Little John, were in the spotlight. Crew from Discovery Channel howering over goading them to verbalize what they were thinking. DARPA radio crackling, reporting the issue to higher up the chain. The teams in line for e-stop testing were queuing up. Just a frenzy of activity and excitement. Top it all the Sun was showing no mercy either. The high desert has no clouds. If anything is blocking the heat, its the smoke from the fires on the west.

Most people would crack under such pressure.  But Suresh and Joshua have been hardened, having gone through such things and worse in the past two challenges. This is first experience for Little John, and he was holding his nerves well. The trio, who were the only people around the bot, were thinking on their feet as fast as they could. They came up with a slew of possibilities. Its hard to believe all of the possibilities they came up with turned out to be correct. Very soon they ran out of clock, and had to give way to the next team.

Just to be fair to the team, we are not the only team in this boat. There are other teams that have experienced problems as well. That’s what makes this challenge so much fun.

We are now schedule for a re-test at 1700. But DARPA is running behind schedule, and its possible we may have a retest in the morning.

– Arun Lakhotia