Lecture 6: Sensors and Actuators of NAO

Transcription

1 Lecture 6: Sensors and Actuators of NAO Cognitive Systems - Reading Club Christian Reißner Based on slides by Mike Beiter, Brian Coltin and Somchaya Liemhetcharat Applied Computer Science, Bamberg University Last change: May 14, 2014 Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

2 Overview Today s Topics Short introduction into Python Sensors of the NAO Actuators of the NAO Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

3 Python A Short Introduction Philosophy of Python I/II Beautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. Special cases aren t special enough to break the rules. Although practicality beats purity. Errors should never pass silently. Unless explicitly silenced. Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

4 Python A Short Introduction Philosophy of Python II/II In the face of ambiguity, refuse the temptation to guess. There should be one and preferably only one obvious way to do it. Although that way may not be obvious at first unless you re Dutch. Now is better than never. Although never is often better than *right* now. If the implementation is hard to explain, it s a bad idea. If the implementation is easy to explain, it may be a good idea. Namespaces are one honking great idea let s do more of those! Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

5 Python Blocks Blocks in Python Structuring by indentation no brackets! no keywords! forced clarity by sequences of spaces or indentations as syntax element calculation of faculty with C: int fakultaet(int x) { if (x > 1) { return x * fakultaet(x - 1); } else { return 1; } } calculation of faculty with Python: def fakultaet(x): if x > 1: return x * fakultaet(x - 1) else: return 1 Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

6 Python Reserved Words Reserved Words The following list shows the reserved words in Python. These reserved words may not be used as constant or variable or any other identifier names. and exec not assert finally or break for pass class from print continue global raise def if return del import try elif in while else is with except lambda yield Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

7 Python Data Types Data Types and Variables Python does not necessarily need a data type Data are interpreted directly Example: >>> i = 42 >>> i = i + 1 >>> print i 43 String: >>> s = "Python" >>> print s[0] P >>> print s[3] h Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

8 Python Loops& Branches Loops Python offers only two loops. For and while. Python has fewer syntactic constructions than many other structured languages While: #!/usr/bin/env python n = 100 sum = 0 i = 1 while i <= n: sum = sum + i i = i + 1 print "Sum of 1 to %d: %d" % (n,sum) Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

9 Python Loops& Branches Branches Python offers only two loops. For and while. Branches: IF ELIF ELSE If: #!/usr/bin/env python if expression1: statement(s) elif expression2: statement(s) elif expression3: statement(s) else: statement(s) Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

10 Python Functions Functions Key word for functions is def Example for a function with optional parameters #!/usr/bin/python def add(x, y=5): """Gib x plus y zurueck.""" return x + y print add(2, 3) Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

11 Python R/W Read and Write Data Sets Example: Read a file and outputs it line by line fobj = open("yellow_snow.txt") for line in fobj: print line.rstrip() fobj.close() Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

12 Python R/W Read and Write Data Sets Example: Write into a file fobj = open("yellow_snow.txt") for line in fobj: print line.rstrip() fobj.close() w parameter for write Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

13 Python Modules Modules Libraries (Bibliotheken) - (data types and functions for all Python-programs) the extensive standard library own library s library s of third-party s local modules - (only for one program) integration by import math Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

14 Python Modules Different kinds of modules There are different kinds of modules written in Python ending:.py dynamic loaded C-modules ending:.dll,.pyd,.so,.sl usw Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

15 Python Modules Search Paths If you want import a module e.g. abc the interpreter searches in the following order 1 Current directory 2 PYTHONPATH 3 If PYTHONPATH is not set the system searches in default-path e.g. /usr/lib/python2.7. in Linux/Unix You may find out a module position by >>> import math >>> math. file /usr/lib/python2.5/lib-dynload/math.so >>> import random >>> random. file /usr/lib/python2.5/random.pyc Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

16 Python Modules Module Content Get defined names of module with the build-in-function dir() >>> dir(math) [ doc, file, name, acos, asin, atan, atan2, ceil, cos, cosh, degrees, e, exp, fabs, floor, fmod, frexp, hypot, ldexp, log, log10, modf, pi, pow, radians, sin, sinh, sqrt, tan, tanh ] >>> Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

17 Python Questions to Python? End of Introduction Questions? Are you missing something? Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

18 NAO Back to NAO Sensors Actuators Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

19 NAO Sensors How feels NAO? Human senses: hearing, sight, touch, smell, taste other senses like sense of balance, the sense of temperature, and kinesthetic sense NAO s senses: Two cameras in its head Four microphones into its heat A tactile sensor on its head that is split into three parts The chest button Two foot bumpers No sensors that allow it to smell or taste things *images by Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

20 NAO Sensors Eye Color & Foot Bumpers Change NAO s Eye Color by Foot Bumpers Write a box that change the eye color of NAO red with the left bumper and green with the right bumper Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

21 NAO Sensors Monitor Sensing with Monitor We will learn how to observe the raw sensor values of the robot and graph them with Monitor Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

22 NAO Sensors Monitor Sensing with Monitor 1 Run Monitor in the same directory that you run Choregraph 2 Click on Memory We want observe some of the sensors This informations are stored in the NAO s memory 3 Select your robot from the list and connect it 4 Select New Configuration. 5 A dialog window appears. Check View Devices at the bottom 6 Scroll down until you find Device/SubDeviceList/ InertialSensor/AccX/Sensor/Value, and check this item. Also select.../accy/sensor/value and.../accz/sensor/value 7 These are the accelerometer readings along the x,y and z axes. 8 Click OK Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

23 NAO Sensors Monitor Sensing with Monitor Check boxes Watch All Graph All and change the Subscription Mode to Every nb ms the axis accelerometer reading will appear on the graph. Try turning NAO in all directions Try it with other sensor readings Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

24 Actuators Actuators of NAO NAO has an internal gyroscope and accelerometer inside its torso for the balance the gyroscope measures angular velocity the accelerometer measures acceleration together they tell NAO if it is upright, lying on its back, or lying on its front Additionally, the two sensors let the NAO know if it is falling down, so it can brace itself for a fall with its arms. Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

25 Actuators Actuators of NAO you can control the whole pose of NAO s entire body for example, the NAO can calculate how far the hand is from the head it does so using a kinematic chain, which essentially uses trigonometry to calculate relative positions of joints the picture on the right shows a two-link arm with an elbow joint using the length of the arms and the angle of the elbow, we can calculate the position of the end-effector relative to the base Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

26 Exercises LED Disco Exercise Use each of the three head buttons to control one of the three color components: red, green and blue. By combining these colors, we can make others. For example, red and blue together will make purple, and red and green make yellow. How to do so? 1 add a new box. Add three inputs for the colors (boolean) 2 add a Tactile Head box (Sensors), and connect the outputs to the new box the three outputs of the Tactile Head box trigger when the head buttons are touched 3 configure the Python code of your box initialise the LED s ( def init (self): ) implement a toggle of the colors ( oninput onstop(self): ) Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

27 Exercises LED Disco cont. Exercise Make this box thing 1 add a new box. Add three inputs for the colors (boolean) 2 add a Tactile Head box (Sensors), and connect the outputs to the new box Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

28 Exercises LED Disco cont. Exercise Let s do Python 1 add a new box. Add three inputs for the colors (boolean) 2 add a Tactile Head box (Sensors), and connect the outputs to the new box 3 configure the Python code of your box initialise the LED s ( def init (self): ) Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

29 Exercises LED Disco cont. Exercise Let s do Python 1 add a new box. Add three inputs for the colors (boolean) 2 add a Tactile Head box (Sensors), and connect the outputs to the new box 3 configure the Python code of your box initialise the LED s ( def init (self): ) implement a toggle of the colors ( oninput onstop(self): ) Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

30 Exercises LED Disco cont. Exercise All in one: Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

31 Exercises Mirror, Mirror on the Wall Mirror, Mirror on the Wall One more sensor of NAO is its encoder. Now we will disable stiffness on one of the NAO s arms so that it can moved freely then, we will use the encoders to read the position of the other arm and mirror these same position on the NAO s other arm You move one arm the other arm will follow Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

32 Exercises Mirror, Mirror on the Wall Mirror, Mirror on the Wall Do it 1 create a Bumpers box, and connect it to a custom Mirror Joints box Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

33 Exercises Mirror, Mirror on the Wall Mirror, Mirror on the Wall Do it 1 create a Bumpers box, and connect it to a custom Mirror Joints box 2 enter the Python code shown on the right into your custom box Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34

34 Exercises Mirror, Mirror on the Wall Mirror, Mirror on the Wall Do it 1 create a Bumpers box, and connect it to a custom Mirror Joints box 2 enter the Python code shown on the right into your custom box 3 run the behaviour. Press the foot bumper, and move the robot s arm Christian Reißner (CogSys, WIAI) RC Sensors and Actuators May 14, / 34