1. Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics  TEMA  IEETA  http://www.mec.ua.pt/robotics Simulation Tools for a Real Humanoid Robot Pedro Ferreira 1 Filipe M. T. Silva 1 Vítor M. F. Santos 2 1 Department of Electronics and Telecommunications 2 Department of Mechanical Engineering University of Aveiro, PORTUGAL

2. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Overview  Humanoid overview  Inclinometers  From measure to control  High-level motion algorithms  Bipedal locomotion  Rotation  Kick  Simulation Platform  Why Matlab?  Specification and functionalities  Limitations  About Future

3. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Humanoid Structure  Complete humanoid model  22 degrees of freedom  Weight - 5 kg  Height - 60 cm  Max. width - 25 cm  Foot print - 20  8 (cm 2 )  Actuation  Servomotors with transmission ratio  Sensors  A vision Camera (CCD)  Servos’ position (through its internal potentiometers)  Sensitive foot to applied forces  Accelerometers/Inclinometers  Gyroscopes

4. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Local Control  Each slave controller is made of a PIC 18F258 device with I/O interfacing  All slave units:  Connect up to 3 servomotors  Have a common base (a piggy- back unit can add I/O sensors)

5. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Distributed Control System  A Main Control Unit (PC):  Exchanges high-level orders and interacts with the camera.  RS-232 communication with the Distributor unit.  Distributor Unit (Master):  Interface between the Main and the Local control units.  Adapts the RS-232 to CAN commands (and vice-versa).  8 Local Control Units (Slaves):  Control the low-level features of the several devices.  CAN bus to connect them. Main Control RS232 Master CAN BUS 1 2 3 1 2 3 1 2 3 1 2 1 2 3 1 2 3 1 2 3 1 2 Slaves

6. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Accelerometer/Inclinometer  The Accelerometer/Inclinometer used is ADXL202E (Analog Devices).  It can measure accelerations with a full-scale range of ±2G.  It can measure both dynamic acceleration (e.g., vibration) and static acceleration (e.g., gravity).  When the accelerometer is oriented so both its X and Y axes are parallel to the earth’s surface it can be used as a two axis tilt sensor with a roll and a pitch axis.

7. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics From Measure to Control  Proportional Control  Delta = error*2.5*K*1e-2; Delta is the increment applied to servo Error is the difference between the wanted and the measure inclination 2.5 is the transmission ratio of servo K*1e-2 is the real gain of controller  K vary between 10 and 50 Higher values give rise to oscillations Lower values has a very slow effect

8. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Inclinometers Experiment  Experiment condition  Varying reference CoP, so the leg perform a square trajectory  Square with ~15cm width  2 seconds to perform a edge  Controller gain was 30  Response of inclinometer controller  Max delay = 0.797 seconds  Max error = ~9 degrees

9. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics High-level Motion Algorithms  Quasi-static Motion  All the movements are planned at a low velocity and with the CoP always on the support foot.  Locomotion  Essential algorithm based on a quasi-static walking motion which assure that the CoP is always on the support foot.  Rotation  Very important movement with tricky aspects.  Kick  Simple movement  Stair Walking  Not yet developed!

10. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Bipedal locomotion 1  Cartesian space  Specification Parameters  Step Length  Hip height  Hip y-coordinate center position  Foot max elevation  Divided in 4 phases  Prepare  Start Step Middle point  End of step  Prepare Next Step 1 Developed by Professor Filipe Silva

11. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Bipedal Locomotion  Multiple Steps

12. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Rotation 1  Cartesian and joint space motion plan  Specification Parameters  Inclination angle  Rotation angle  Hip height  Foot max elevation  Divided in 10 phases  Prepare  Rise free foot  Rotate  Align CoP with new support foot  Finish movement 1 Developed by Professor Filipe Silva

13. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Rotation  Tricky aspect  Rotation axis isn't align with the foot  Final foot position isn’t align with the hit  Need adjust booth hit rotation joint to change the CoP to the new support foot

14. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Kick  Specification Parameters  Inclination angle  Hip height  Foot max elevation  Divided in 4 phases  Prepare  Align CoP with new support foot  Rise free foot  Kick

15. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Simulator TwoLegs_22dof  Motivations  Turn the interaction with the robot more easy  Need to assemble multiple work already developed like high-level movements, control adjust, communication interface…  Create an interface that allow a new user start playing with the robot in a more intuitive way  Developed on Matlab tool GUIDE

16. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Why Matlab?  Disadvantages  Not the most flexible  Poor GUI development objects  Often must use tricks and unfriendly techniques  Slow performance  Advantages  Communications protocol already developed  Mathematical solutions (inverse and direct kinematics among others mathematical operations)  Easy integration of new work developed on Matlab  Easy and intuitive development environment  Do you speak Matlab? A little bit! No need to learn object oriented languages like Visual Basic, C++, C#, …

17. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Specifications and Functionalities  Joint space motion plan  Integrate high-level movements  Plot adjusts like  Change ground dimensions and position  Put in Ball  Put in Stairs  Show CoG and CoP  Communication interface  Allow send and receive joint position for/from Humanoid robot  Trajectory plane visualization  Plot all the trajectory that the SCU will build up, with all the phases of the entire movement

18. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Limitations  Besides the Matlab limitations already pointed…  Isn’t modeled dynamic forces  Do not detect components collision  Has no physical joint limitations  Need to know the implementation to include new high-level movements  Don’t allow to change the slaves local control  Only joint movements are allowed on the main windows

19. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics Future work  Modeling dynamic forces  Include different terrain topologies  Highlight active joint when performing a move  Develop different ways of doing the same movement  Allow dynamic adjust of PID parameters  Include a virtual image of the real Humanoid Robot  Modeling all the sensor which take in redundancy and better control  (…)

20. UNIVERSITY OF AVEIRO, PORTUGAL Centre for Mechanical Technology and Automation Institute of Electronics Engineering and Telematics The End