Two Legged Robot Design, Simulation And Realization

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  • 18/12/06
  • Two Legged Robot Design, Simulation And Realization

    1. 1. Two-Legged RobotDesign, Simulation and Realization (Sep-2006 to May 2007)Guided By: Prepared By: Dr. S N. Pradhan Nirav A. Patel Prof. K D. Shah ( 05mce011)
    2. 2. Architecture of two-legged robotMay 28, 2012 M.Tech Major Project 2
    3. 3. Subsystems of the robot• Mechanical subsystem• Electronics subsystem• Software subsystemMay 28, 2012 M.Tech Major Project 3
    4. 4. Mechanical subsystem• This subsystem focuses on • Actuators • CAD drawing of robot • Torque and speed calculation • Dimensional specification of the robotMay 28, 2012 M.Tech Major Project 4
    5. 5. Mechanical Subsystem• Consists of • Stepper motor for open loop control of different joints • Gearbox for increasing torque • CAD model showing placement of different componentsMay 28, 2012 M.Tech Major Project 5
    6. 6. Stepper Motors• Provides good open loop control by means of rotating one step per signal applied• Types • Unipolar • Less torque • Easy to control • Bipolar • Greater torque • Harder to control compared to Unipolar motorsMay 28, 2012 M.Tech Major Project 6
    7. 7. Stepper motors from precisionmotors Specifications D-48-42-B20 D-48-42-B25 D-48-42-B28 Units Bipolar Bipolar Bipolar Medium Torque High Torque High Torque Operating Voltage V 6 12 24 Resistance per phase ohms 2.7 6 15 Inductance per phase mH 3 6 12 Holding Torque mNm(oz-in) 94.9 (13.47) 148 (21.1) 164 (23.3) Detent Torque mNm(oz-in) 18.5 (2.67) 18.5 (2.67) 18.5 (2.67) Rotor Inertia g-m2 25.6 x 10-4 25.6 x 10-4 25.6 x 10-4 Weight gms (oz) 185 (6.52) 185 (6.52) 185 (6.52) Step Angle degrees 7.5 7.5 7.5 Step angle accuracy o +/- 0.5o +/- 0.5o +/- 0.5o Max. operating oC 100 100 100 temperature Dielectric strength - 1000 VAC for 1 min. 1000 VAC for 1 min. 1000 VAC for 1 min. End play mm (in) 0.2 (0.008) 0.2 (0.008) 0.2 (0.008)May 28, 2012 M.Tech Major Project 7
    8. 8. Torque characteristicsMay 28, 2012 M.Tech Major Project 8
    9. 9. Locations of Degrees of Freedom • figure shows position of all motors • ML1:Clock-AnticlockRotation of Ankle joint. • ML2:Up-Down movement of Ankle joint. • ML3: Movement of Knee joint. • ML4:Up-Down movement of Pelvis joint. • ML5: Clock-Anticlock rotation of pelvis jointMay 28, 2012 M.Tech Major Project 9
    10. 10. Values for torque calculations• Motor Weight = 185 gram• Gearbox Weight = 350 gram• Controller Weight = 50 gram• Other material weight = 1 kg• We also assume that total height will be 60 cm so distance of CG from any motor will not be more than 30 cm.May 28, 2012 M.Tech Major Project 10
    11. 11. Torque required by ML1Since this is the motor requiring maximum torque when it has to lift rest of the body to maintain CG.So weight required to be lifted by this motor is W = No of Motors *(Motor Weight + Controller Weight Gearbox weight) + Other Material Weight. (in gram) = 9 * (185 + 50 + 350) + 1000 =6265 gram =6.265 KgNow maximum torque required by this motor is T = W * 30 = 6.265 * 30 =187.95 Kg-cm May 28, 2012 M.Tech Major Project 11
    12. 12. Torque required by ML5 Weight required to be lifted by this motor is W = No of Motors *(Motor Weight + Controller Weight Gearbox weight) + Other Material Weight. (in gram) = 5 * (185 + 50 + 350) + 1000 = 3925 gram = 3.925 Kg Now maximum torque required by this motor is T = W * 30 = 3.925 * 30 = 117.75 Kg-cmMay 28, 2012 M.Tech Major Project 12
    13. 13. Motor and gearbox specifications• Stepper Motor • Motor Model : D-48-42-B28 • Weight = 185 gram • Holding Torque = 1.24 Kg-cm • Operating Voltage = 24V • Step Angle = 7.5 degree• Gearbox • Gearbox Model:GB4 • Maximum torque = 200 Kg-cm • Gear efficiency = 0.6May 28, 2012 M.Tech Major Project 13
    14. 14. Available torque calculation…• Suppose we assume that • N is Gear Ratio • To is Output torque at gearbox shaft • Ti is input torque to gearbox • Tm is torque produced by motor • Ge is gearbox efficiency• Then, • To = Ti * Ge * N or To = Tm * Ge * N because Tm=TiMay 28, 2012 M.Tech Major Project 14
    15. 15. Available torque calculation• Here, • Tm = Ti = 1.24 Kg-cm • Ge = 0.6 • To = 187.95 Kg-cm• So, • 1.87.95 = 1.24 * 0.6 * N • =>N = 252.62May 28, 2012 M.Tech Major Project 15
    16. 16. Dimensional specifications of robotMay 28, 2012 M.Tech Major Project 16
    17. 17. Mechanical CAD drawingMay 28, 2012 M.Tech Major Project 17
    18. 18. Factors affecting the design• Weight of motors. • Should be less enough so that it meets torque requirements• Weight of Gearbox • Should be less enough compared to maximum torque at output shaft• Torque of Motors • Should be high enough to lift the whole body when combined with gearboxMay 28, 2012 M.Tech Major Project 18
    19. 19. Electronics subsystem• This subsystem focuses on • Microcontroller development board and its connection with stepper motor controllers • Microcontroller and its interfacing with computerMay 28, 2012 M.Tech Major Project 19
    20. 20. Electronics subsystem• Consists of • Microcontroller development board • Atmel 89S52 In system programmable Microcontroller • Stepper motor controllers • A3982 from Allegro MicrosystemsMay 28, 2012 M.Tech Major Project 20
    21. 21. Microcontroller• Used to control movements of stepper motors and to communicate with PC• Easy to program with the help of development boards available in the market• 89S52 is one of the most popular 8-bit Microcontroller which have 4 output ports so provides enough no of pins to control more no of motors• 89S52 can easily interfaced with PCMay 28, 2012 M.Tech Major Project 21
    22. 22. AT89S52 PCB layoutMay 28, 2012 M.Tech Major Project 22
    23. 23. AT89S52 development boardMay 28, 2012 M.Tech Major Project 23
    24. 24. Stepper Motor Controller• Controlling stepper motor just by 2 signals instead of one for each coil which ranges from 4 to 8• Reduced programming complexity• Two signals per motor • Step • Direction (CW/ACW)May 28, 2012 M.Tech Major Project 24
    25. 25. Functional block diagram of A3982May 28, 2012 M.Tech Major Project 25
    26. 26. Block diagram representation ofA3982May 28, 2012 M.Tech Major Project 26
    27. 27. Microcontroller Development boardand stepper motor controllersMay 28, 2012 M.Tech Major Project 27
    28. 28. Software subsystem• This subsystem focuses on • Controlling stepper motors to establish stable walking • Generating stable walking pattern• It consists of • Two-legged robot simulator • Application Specific Compiler • Torque AnalyzerMay 28, 2012 M.Tech Major Project 28
    29. 29. Two-Legged Robot simulator• Simulates movements of different parts of body• Can be used to analyze movements and their effects on centre of gravity• Shows 3D model on computer screen• Provides GUI with buttons for applying movements to different parts.May 28, 2012 M.Tech Major Project 29
    30. 30. Need for Two-Legged RobotSimulator.• Development of humanoid costs a lot so its better to use computer for simulation at low cost.• It can simulate almost all possibilities.• Can go for applying different algorithms without applying much more changes in design.May 28, 2012 M.Tech Major Project 30
    31. 31. Snapshots of the simulatorMay 28, 2012 M.Tech Major Project 31
    32. 32. Isometric view of robotMay 28, 2012 M.Tech Major Project 32
    33. 33. Front view of robotMay 28, 2012 M.Tech Major Project 33
    34. 34. Side view of the robotMay 28, 2012 M.Tech Major Project 34
    35. 35. Top view of the robotMay 28, 2012 M.Tech Major Project 35
    36. 36. Application specific compiler(ASC)• Special type of compiler having application specific instruction set• Developed compiler is for two-legged robot which have instructions like • MOVE LEFT LEG UP BY 5 • ROTATE LEFT ANKLE CLOCKWISE BY 34• Generates assembly language code for 8051 family of microcontrollersMay 28, 2012 M.Tech Major Project 36
    37. 37. Flowchart of ASCMay 28, 2012 M.Tech Major Project 37
    38. 38. Instructions supported by ASC Instruction Joint Actuated ROTATE LEFT ANKLE CLOCKWISE BY Left Ankle(Rotate) ROTATE LEFT ANKLE ANTI-CLOCKWISE BY Left Ankle(Rotate) MOVE LEFT ANKLE UP BY Left Ankle(Move) MOVE LEFT ANKLE DOWN BY Left Ankle(Move) MOVE LEFT KNEE UP BY Left Knee MOVE LEFT KNEE DOWN BY Left Knee ROTATE LEFT LEG CLOCKWISE BY Left Leg(Rotate) ROTATE LEFT LEG ANTI-CLOCKWISE BY Left Leg(Rotate) MOVE LEFT LEG UP BY Left Leg(Move) MOVE LEFT LEG DOWN BY Left Leg(Move) ROTATE RIGHT ANKLE CLOCKWISE BY Right Ankle(Rotate) ROTATE RIGHT ANKLE ANTI-CLOCKWISE BY Right Ankle(Rotate) MOVE RIGHT ANKLE UP BY Right Ankle(Move) MOVE RIGHT ANKLE DOWN BY Right Ankle(Move) MOVE RIGHT KNEE UP BY Right Knee MOVE RIGHT KNEE DOWN BY Right Knee ROTATE RIGHT LEG CLOCKWISE BY Right Leg(Rotate) ROTATE RIGHT LEG ANTI-CLOCKWISE BY Right Leg(Rotate) MOVE RIGHT LEG UP BY Right Leg(Move) MOVE RIGHT LEG DOWN BY Right Leg(Move)May 28, 2012 M.Tech Major Project 38
    39. 39. Snapshot of ASCMay 28, 2012 M.Tech Major Project 39
    40. 40. Complete flow of Simulator andCompiler• 1: Write high level code in ASC• 2: Verify the code using simulator for desired functionality• 3: Compile the verified code to generate Assembly language code for specific Microcontroller• 4: Compile Assembly code using Assembler to generate Hex file• 5: Load the Hex file in the MicrocontrollerMay 28, 2012 M.Tech Major Project 40
    41. 41. High Level Language ProgramMay 28, 2012 M.Tech Major Project 41
    42. 42. Verify the programMay 28, 2012 M.Tech Major Project 42
    43. 43. Compile the verified programMay 28, 2012 M.Tech Major Project 43
    44. 44. Load in the KeilMay 28, 2012 M.Tech Major Project 44
    45. 45. Logic AnalyzerMay 28, 2012 M.Tech Major Project 45
    46. 46. Torque Analyzer• Torque analyzer • Records torque required by each joint of robot while program is being executed by ASC. • Shows recorded data in form of graphs.• Program to take first step from start position rotate left ankle anti-clockwise by 35 , rotate left leg clockwise by 35 , rotate right leg anti-clockwise by 35 , rotate right ankle clockwise by 35; move right leg up by 60 , move right knee down by 30;move right leg up by 32 , move left leg down by 32 , move right knee down by 32 , move left ankle down by 40; move right knee up by 32 , move right ankle down by 40;May 28, 2012 M.Tech Major Project 46
    47. 47. Torque required at right knee jointMay 28, 2012 M.Tech Major Project 47
    48. 48. Torque required by all the jointsMay 28, 2012 M.Tech Major Project 48
    49. 49. Conclusion• For two-legged robots torque requirements are very high compared to multi legged robots and wheeled robots.• Balancing is one of the most difficult tasks for two-legged robots.• In the Table 1 maximum torque required by robot without including dynamics of the robot are given for taking one step forward from rest condition.• From the table we can conclude that knee joint requires highest torque.May 28, 2012 M.Tech Major Project 49
    50. 50. Table 1. Maximum torque requiredby joints of robot Joint Name Maximum Torque Kg-cm Left Ankle(Up/Down) 145 Left Ankle(Clock/Anti-clock) 43 Left Knee 0 Left Pelvis(Up/Down) 70 Left Pelvis(Clock/Anti-clock) 53 Right Ankle(Up/Down) 2 Right Ankle(Clock/Anti-clock) 43 Right Knee 34 Right Pelvis(Up/Down) 77 Right Pelvis(Clock/Anti-clock) 46May 28, 2012 M.Tech Major Project 50
    51. 51. References• Satoru Shirata, Atsushi Konno, and Masaru Uchiyama, “Design and Development of a Light-Weight Biped Humanoid Robot Saika-4”, Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems, Sendai, Japan, September 28 - October 2, 2004, pp. 148-153.• Rainer Bischoff and Tamhant Jain,”Natural Communication and Interaction with Humanoid Robots”, Second International Symposium on Humanoid Robots, Tokyo, Japan, October 1999.May 28, 2012 M.Tech Major Project 51
    52. 52. References…• Qiang Huang, Yoshihiko Nakamura, Hirohiko Arai, and Kazuo Tanie, “Development of a Biped Humanoid Simulator”, Proceedings of the lEEE/RSJ International Conference on intelligent Robots and Systems , Takamatsu, Japan, Vol. 3, 2000, pp. 1936-1942.• Riadh Zaier, “Motion Generation of Humanoid Robot based on Polynomials Generated by Recurrent Neural Network”, Proceedings of the First Asia International Symposium on Mechatronics, Xi’an, China, September 27-30, 2004.• Tetsuro Kitazoe, “Unsupervised Learning of Two Legged Robot”, IEEE International Workshop on Robot and Human Communication, Nagoya, Japan , 18-20 Jul, 1994, pp. 351-355.May 28, 2012 M.Tech Major Project 52
    53. 53. References…• Andre Senior, and Sabri Tosunoglu, “Design of a Biped Robot”, Florida Conference on Recent Advances in Robotics, Miami, Florida, May 25-26, 2006.• Kazuo Tanie, “Humanoid Robot and its Application Possibility”, IEEE Conference on Multisensor Fusion and Integration for Intelligent Systems, 30 July-1 Aug, 2003, pp. 213 – 214.• “ASIMO Technical Information”, American Honda Motor Co. Inc. Corporate Affairs and Communications, January 2003. ,http://asimo.honda.com/downloads/pdf/asimo-technical- information.pdfMay 28, 2012 M.Tech Major Project 53
    54. 54. References• “History of ASIMO” http://asimo.honda.com/AsimoHistory.aspx• “Stepper Motor Specifications”, Precision Motors, http://www.pmpl.co.in/d4842bi.pdf• “Gearbox Specifications”, Mech-Tex Manufacturing Co., http://www.mechtex.com/PDF/gb4.pdfMay 28, 2012 M.Tech Major Project 54

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