Dallas BEST 2014 Blade Runner

Transcription

1 Dallas BEST 2014 Blade Runner Software Training 1

2 Easy C software training If needed, get your 150day EasyC licence code at Rkit pickup. Must run as admin to install EasyC license. RobotC and Simulink (Matlab) are also available, but not supported well locally. See additional training materials for these at BESTinc.org website. 2

3 SPA: Sense Plan Act Arcade2(,,,,,) : SPA all in one step Sense 2 joysticks Plan mix of joysticks to set motors Act by setting Motor port speeds JoysticktoMotorAndLimit : also 1step SPA Sense joystick and limits switch Plan to set motors, unless limit switch Act by setting Motor port speeds 3

4 SPA: Sense Plan Act Arcade2(,,,,,) : SPA all in one step Sense 2 joysticks Plan mix of joysticks to set motors Act by setting Motor port speeds JoysticktoMotorAndLimit : also 1step SPA Sense joystick and limits switch Plan to set motors, unless limit switch Act by setting Motor port speeds 4

5 SPA on your own Sense: Var1 = GetJoystickAnalog(); Var2 = GetDigitalInput(); Plan: If this or that then set var_mp3 = 2* var1; If Var2 then set var_mp3 = 0; // change mind Act: SetMotor( 3, var_mp3); 5

6 Common problems/solutions Robot drives backwards You have left/right wheel motors swapped HW fix by swapping motor plugs vs ports Or SW fix by swapping motor#s in code Robot spins instead of drives straight One motor needs polarity reversal HW fix by reversing 2wire to motor Or SW fix by using invert direction 6

7 Dallas BEST 2014 Blade Runner Build session Training 7

8 Main Points for Mentors/Coaches Students do all the work! See Generic Rules Follow the Engineering Design Process Document EDP in Engineering Notebook: Make it easy on Notebook graders by following order of judging guidelines Don t miss points by leaving out topics (eg safety) Keep the robot simple! Make practice field element (adults can do) Lots of practice time for all drivers helps lots! Follow the Q&A to keep up with Rule changes/clarifications. 8

9 Common Robot Failures Motor axle attachment Insufficient gearing on Arm motor Belt slips on pulley due to too much torque, vs insufficient tension. Late design of grippers (key part) Servos are weak, overheat easily when used in dual-opposing/fighting gripper. Friction in joints; (use bearings ) 9

10 Robot Example Pictures Driving game this year Look at the Arms and gripper mechanism Simple pivot arm: gripper moves with arm Arm wheel pulley and string to small shaft Toothed pulley Counter-weight or bungee spring 4-bar arm: gripper stays parallel More joints, easier to do springs. 10

11 New this year, common ¼ shaft Usual BEST robots use LARGE motors for wheels, especially when dragging game pieces, or climbing a ramp. BUT some teams have success with small (weak but faster) motors on wheels, if they use small enough wheels. Since motors have same shaft sizes now, it is easier to try both ways. 11

12 Small motor for claw actuator FOD bumpers 12

13 Igus slider 2 stage elevator arm lift 4 bar aluminum arm, Secondary linear lift 13

14 Side fold hinge parallel arm Allows very long arm, (thinking out of the 24 box) 14

15 Dual servo slide pincher claw grips from the top, can pickup pieces from the ground Curved bumper with wheel protector 15

16 Arm Counter- Weight box includes battery, also bungee spring assist 16

17 Vertical lift to hang the plane Parallelogram forklift with servo clamp Base notch so robot can hug airplane from behind, lift under wings 17

18 Folding forklift with double slide lift Note: Rubber tread on wheels 18

19 Notes on toothed Pulleys Do not do any drilling on the pulleys No holes in the large pulley, no change to the set screws. Plastic idler pulley may only be used with shoulder bolt. Do not modify the round belt, only straight 3 belt may be modified Setscrew allen wrench size is 1/16 Pulley set may be unreliable unless idler is used to get extra wrap on small drive pulley. Proper belt tension is also important. Added Plastic Idler pulley on shoulder bolt <8 of 18 teeth touching belt Now >12 of 18 teeth touching belt 19

20 Igus Spherical bearings vs RAZZ ball bearings The usual Igus parts bag is late, may not make kickoff. RAZZ ball bearing Stronger (made of steel) ball bearings (rotates easily) Requires nested pocket Requires retainer (or shaft nut) Difficult to align 2 correctly IguBall spherical bearing Igus Iguball bearing Light weight Self-lubricating nylon sleeve Use with drylin black rod Built in mount & retainer Sphere self-aligns +/- 10 RAZZ ball bearing Axel (1/4 rod) 20

21 DC Motor Torque vs Speed BEST POWER at 50-60% of free motor speed Scale current Torque Speed Power Eff

22 Build Operations: Work in teams of 2 students coach is welcome too Wear Safety glasses at all times in room Must have Closed toe shoes (no sandals) N different tasks Queue manager will provide organization 22

23 Bending Motor mounts Gripper motors, or motors mounted in Arm tower may not want bent mounts. You can cut off bent parts later if you change your mind. Alternate activity: cut ½ Aluminum in bend vice with hacksaw Some people say its possible to cut Al with a hacksaw: find out if you agree Trade-off people, keep steady, build muscle! 23

24 #1: Soldering Motors and Potentiometers Materials to bring Bring 4 motors, limit switches, volume knob red and black motor wire, cat5 (thin multistrand) wire Heat shrink tubing, zip-ties Solder red/black wires to motors Use thin wire on limit switches Rotate several people through this station if you have a large team 24

25 Solder Station What to Bring?: R-kit bring entire box C-kit items Potentiometer (volume knob), limit switch red/black wire for motors Thin wire for switches Heat Shrink tubing Zip-ties Operations: Cut to wire length & strip ends of wires Solder ends to motors, cut off excess Apply heat-shrink tubing Zip-tie wires to motor body for strain relief 25

26 Analog Potentiometer soldering aka Volume knob An example showing how to connect a potentiometer to an analog input port is shown in Figure 5. IMPORTANT, the signal terminal of the potentiometer should be connected to the signal pin of the analog input port (Knob looks different this year) 26

27 Axle connectors This is usually the hardest, most critical item for rookie teams. Don t do this right, and your axles will fall off. This build session will help you do it right. Materials: Aluminum block ½ thick Use drill press, thread taps, and chopsaw to form the aluminum block into axle connectors. 27

28 Wheel Hubs What to Bring: 2x12x1/2 Aluminum What is it? Connects Motor Axle to wheel 2 by 2 Operations: drill corner holes for press-fit-nuts Drill axle hole (off-center for short setscrew) Drill set-screw hole in edge Cut to length on chop saw 28

29 Chopsaw Aluminum work Chopsaw (outside) Practice without aluminum first, go slow Sand edges (12 edges per block) 1 swipe each edge, sandpaper flat on table Chop after all drilling, but before press-nut 29

30 Drill Press: Drill press station: (eye protection) Rotate chuck by hand to show bit is straight Every time you change the bit Use drop of oil, vacuum, pause to clip spiral HOT! Use wire tool to move block to water! Then to rag to dry it off 3/8 x 1/8 deep corner holes using step drill ¼ axle hole using step drill from both sides #21 drill in edge for #10-32 tapped setscrew 30

31 Tap the setscrew holes Clamp Aluminum in vice Dip tap in oil bottle, between each hole to clean off the chips allow to drain a few seconds Use two twist forward, half-twist back, This helps break up the chips Stop half-way through and unscrew tap and clean it, then redo to finish. 31

32 Wheels Use ½ plywood for wheels Cut 1 x2 from 2 x4 plywood with jigsaw Cut into 1x1 squares with jigsaw Mark center holes with template Drill center hole using drill & vertical block Mount squares on board with center pivot, Router out circles, using ¼ depth at a time (4 passes) 32

33 Other activities Brainstorm gripper mechanisms using example game pieces Plug Rkit together and demonstrate default program. Bend motor mounts (in white box) 33

34 Progress Chart School bend solder drill tap chop Wheels D 34 Dallas BEST 201 Rookie Build