Team TWO^©

Mobile Robots

This is the official Mobile Robots Homepage of the Team TWO^©.
The Page is part of an elective project during our studies.

(Best viewed with 800x600)

The Team About The Project The Labyrinth The Headlight The Robots Eyes Straight On Driving The Programming The Final Presentation Download Area Link Area Why Do We Enjoy This   Project ? Private Area

Andreas	Claus	Kevin
- Analog IR Sensor Analyzing	- Project Management	- IR- Transmitter Design
- C- Programming	-  Straight On Driving	- The Headlight Development
- Documentation	- Online Documentation     Homepage	- Top Sensor Layout Design
- The Top Sensor Man	- C- Programming	- Documentation
- Top Sensor Layout Design	- The Ground Sensor Man	- Transmitter Modell

Marc	Stefan	Steffen
- C- Programming	- Documentation	- C- Programming
- Documentation	- C- Programming	- Documentation
- Top Sensor Layout     Prototype Manufacturing	- Product Placement	- Software Development

The project is an elective course at the University of Applied Science Kiel, Germany.
This was the first course about mobile robots. Causes of this there were a lot of challenges.
The first was to get the base robots from a company in the USA called Mekatronix(tm).
The robots wait three weeks at the German customs duty.
But Prof. Dr. Dispert, one of the instructors, was able to free the robots.
After that we rearmed the robot with our special equipment.
The base robot is a kit; a lot of parts are from radio controlled model cars and planes. For example, the drive engines are standard model servos and the tires came from a RC airplane.
The heart of the robot is a two layer computer board with a Motorola(tm) 68 000 processor.
We program the robot in 'standard C '. There is also a meta language available, called "PROGO", but this language is not powerful enough .
The inventor of PROGO(tm) is the company Mekatronix(tm).

The Robot had to find an IR- Emitter in the labyrinth. It is not allowed to touch any wall. The Robot had to stop in front of the Emitter and to signal, that he arrived. Perhaps in the future the other Robots are ready, so we can make a championship with other teams.
 
 

We also made the labyrinth	We proudly present: BLACK MAX

The robot in action	The robot stops at a black surface

Because no other team finished their robots at the end of the term, we just made a race:
Human being against our intelligent Robot. You can see the robot in bottom corner on the right.
 
 

There is also a  VIDEO  available (QuickTime(tm) Plug in or MS(tm) Media Player 2(tm) necessary).
Click here to go to the download area.

Here is the original model of the ir- light emitter.	The Robot stops, if he arrived on a back surface.

1.1 Headlight- Rules
(Taken from Un.Aveiro - Electronics Department, May 1998)

1.1.1 Goal area:
The headlight identifies the Goal area. The Goal area is a circle with a 50cm radius, painted in black. The headlight is at the center of the goal area.

1.1.2 Dimensions:
The headlight is 27cm to 29cm high. It stands on a rectangular base 10cm width, 15cm long and 5cm high.

1.1.3 Radiation:
The headlight radiate Infra-Red light, modulated at 25kHz. There are 12 leds in the headlight (MLED81 or equivalent), equally spaced on a 7cm diameter circle.

2 Realization:
2.1 Schematic:

2.2 Functional description:
The schematic is divided into the following three units:

2.2.1 The power unit:
The headlight works with a battery pack or a wired power connection. These two current circles are separated with the relay (V23042). That means if you use the wired power connection the battery pack is disabled.

2.2.1.1 If you use the battery pack the current just runs through the fuse into the oscillation and the sending unit.

2.2.1.2 If you use the wired power connection the input voltage will be fixed down to 7.2V. This is realized with the regulator LM317. You can adjust the voltage with the poti R7 but it should be the same voltage as the battery pack. The input voltage can be from 10V/DC to 23V/DC so that you can use a number of different voltage sources. The two diodes at the input of the voltage unit are just for safety if you change the positive and negative power cables.

2.2.2 The oscillation unit:
The oscillation unit is an standard application of the NE555- oscillator IC. There is to mention that you need the Diode D1 because the impulse time and the pause time of the sending signal should have the same time (20µs+20µs=40µs= 1/25kHz).
You can adjust the pause time with the poti ROFF and the impulse time with the poti RON.
On the output (pin 3) of the NE555 you can measure the rectangular sending signal, which is wired to the base of the switching transistor of the sending unit.

2.2.3 The sending unit
Die IR- diode matrix of the sending unit is made of three IR-diodes in serial (e.g. D2 D3 D4) which are parallel to other three IR-diode in serial (e.g. D7 D8 D9) and that four times. We had to do it that way because we used the IR-diode LD271 with a forward voltage of 1.9V. We are unable to put more than three diodes in serial because our power unit gives a voltage just about 7.2V.
The switching transistor Q1 switches the IR-Diodes in time of the oscillator unit. The parts R14 and C4 are just to speed up the Transistor. The resistors R5 R8 R9 R10 are for regulating the IR diodes current to 250mA. That sounds much but if you take a look into the datasheet of the LD271 you will see that you can pass a forward current up to 310mA if you had an interrupted source voltage like ours.
The announcing diodes (D8 D10 D14 D18) will emit light, if one of the IR-diodes has a defect. If an IR-Diode has a defect there will be a high resistance that means a high voltage. Because of that high voltage the Z-Diodes (D6 D19 D20 D21) will let the reverse current get through and the announcing diodes will spend light.

Testboard:

3. Layout:
We shared the whole schematic into two units for the layout.
The voltage unit and the oscillator unit at the bottom section of the housing. The sending unit at the top of the housing. This got it's advantage because we save a lot of work to wire the sending unit that means that there are just two wires.

Top- View	Bottom- View

4. Measurement:
We measured the voltage at R5 with an oscilloscope. Because R5 is an 10 Ohm resistor we can calculate the current that runs through R5 with the Ohms Law. The current through R5 is the current through the IR diodes that means the sending current.
The measurement of the sending current was in DC- connection with 1V/Div
 
 

Measuring	The HP Plot

As you can see, we measured a sending current of 250mA
Hint: If you work with the wired power opportunity you have to measure with an earth free oscilloscope.

5. Receiver:
The receiving diode of the LD271 is the SFH205F
 

 

To download the layout and the part list click here to go to the download area.

One problem is the straight on driving. The robot has two drives. If both drives turn with the same rate, the robot drive straight on. Cause of the chassis hardware design, the servos has to turn in contradiction direction, to drive forward or backward. The servos have very cheap hammer brushes, so that they have different turns per second in each direction. Ok so long, but the engines have a non-linear behavior. One way to drive on straight is to measure the rotation per minute and program a controller. But we do not have hardware to measure rotation. So we found out a very easy and cheap way to drive on straight. We just try out. We do this with different speeds.
The only problem we have is that the battery voltage is not constant. This is the fact for our solution. We just use a voltage regulation circuit.
 

Chassis Hardware Design	Voltage Regulation Circuit

We program the robot in standard C; the functions for direct hardware access are supported by Mekatronix(tm). Cause we made a competition, there is now only a part of the source code available. Sorry, but you must understand that. We spend a lot of time to program. Ok you can get a little example , download the source code of the example or all executable files.

The function turn(...) lets the robot spin around its axis until the tower is directly in the straight-ahead-position

void turn(int k, int speedr, int speedl, int uirdl, int uirdr)
{

/* the following do-while statement defines the variable k which is non-zero if */
/* the tower is not straight ahead from the robots upper IR's. */
/* while spinning into the straight-ahead-position, k gets smaller */
/* when it reaches a tolerance value smaller than 4, the robots' turn is finished */
        do
        {
              uirdr = UPPER_RIGHT_IR;
              uirdl = UPPER_LEFT_IR;
              if (uirdr > uirdl)
              {
                    speedl = SLOW_SPEED_L;
                    speedr = ZERO_SPEED;
                     k=uirdr-uirdl;
              }
              else
              {
                    speedl = ZERO_SPEED;
                    speedr = SLOW_SPEED_R;
                    k=uirdl-uirdr;
               }
               wait(200);                                                   /* wait for hardware delay*/
               if (k<4) k=0;
               motorp(RIGHT_MOTOR, speedr);
               motorp(LEFT_MOTOR, speedl);
          } while (k);
          motorp(LEFT_MOTOR, ZERO_SPEED);
          motorp(RIGHT_MOTOR, ZERO_SPEED);      /* stop the robots' spinning */
          wait(1000);                                                       /* wait for hardware delay */
}
 
 

The management is content	Guests are also present during the presentation

The instructors inspect our robot	Steffen is also pleased

Download Area

Click here to start downloading the example function: "turn".

Click here to start downloading the final layout and part list. 

Select the video format to start downloading the VIDEO  (249KB).
Intel Indeo(tm) Codec R4.1 or higher required.
- Video for Apple(tm) QuickTime(tm) or Browser QuickTime(tm) Plugin: VIDEO.MOV
- Video for Microsoft(tm) Media Player2(tm): VIDEO.MPG

Please chose the executable files you need:
-  A program to drive trough a channel.
-  A program to stop in front of an obstacle.
-  A program to avoid, if an obstacle is attached.
-  The final race program to find an IR- Emitter in a labyrinth.

   Here are the final source codes for all programs:
               (Restricted access, for instructors only, password required.)
 

Link Area

Interactive Manuals:

• Interactive C User's Guide

Manuals (PDF-files):

• PROGO Applications Manual for the TJ Pro Robot
• PROGO Language Reference Manual
• TJ Pro Education Manual Using IC
• Reinforcement Learning on a TJ Pro

Sharp-Manuals (Links, PDF-files):

• Sensors for Remote Control (Sharp U.S.A.)
• Data for IR Detecting Units
• GP1U58X Series, IR Detecting Unit for Remote Control
• GP1U58Y Series, IR Detecting Unit for Remote Control

IS1U621/IS1U621L, IR Detecting Unit for Remote Control

Having trouble having fun, dancing in the sun	The arrow marks the original light emitter