UBC Thunderbots Robot
UBC Thunderbots is an engineering student design team that designs and creates competitive robots to compete in the Small Size League of the international Robocup Federation. In 2019 we were the champions of the Robocup World Cup Competition in Sidney, Australia. This year we are redesigning the entire robot to add new features and be more optimized. As I lead the mechanical subteam I also helped design the chipper and kicker components of the new fleet of robots.
I made this simplified prototype for the kicker and chipper layout for the Thunderbot’s soccer playing robot. The kicker is mounted on a Geneva drive for multiple shooting angles and the chipper is mounted below. This prototype was to generate ideas for saving space.
This is a more specific prototype I made of a chipper mechanism based off of what was learned from the above prototype. This one was animated to understand the mechanics and relative dimensions of the movement. I also wrote a MATLAB script that takes the inputs of the dimensions of the chipper and the force from the solenoid, and calculated the output force the chipper makes on the ball. The design and script are to be used together to determine a specific design for the chipper.
MATLAB Code
function [forces] = ChipSimpTransfer(density,soltravel,thickness,armwidth,platewidth,Blength,F,H,angle)
%%Purpose: Input parameters and Force and output Force of Chip
% Input: density: density of material
% soltravel: horizontal distance of travel through solenoid
% thickness: thickness of arms
% armwidth: width of arms
% platewidth: width of chipper plate
% Blength: length of horizontal arm of chipper
% F: Input Force from solenoid
% H: Height of center of solenoid from pinned point
% angle: angle of chip plate from the ground (45° probably)
%Output: [forceoutGp forceoutGs; forceoutJp forceoutJs]
% forceoutGp: force at point G assuming thin plate approximation for MMOI
% forceoutGs: force at point G assuming slender rod approximation for MMOI
% forceoutJp: force at point J assuming thin plate approximation for MMOI
% forceoutJs: force at point J assuming slender rod approximation for MMOI
%%Component Variable Setup
%Unit conversions for ease of input
theta=angle*pi/180;
soltravel=soltravel/1000;a
thickness=thickness/1000;
armwidth=armwidth/1000;
platewidth=platewidth/1000;
Blength=Blength/1000;
H=H/1000;
%Constraints for C
dimA=[(sqrt(soltravel^2+H^2)+armwidth) armwidth thickness];
dimB=[(Blength) armwidth thickness];
dimC=[((0.013+armwidth/2)/sin(theta)) (dimB(2)) (platewidth)];
%Calculate Masses of each section of the chipper
ma= density*dimA(1)*dimA(2)*dimA(3);
mb= density*dimB(1)*dimB(2)*dimB(3);
mc= density*dimC(1)*dimC(2)*dimC(3);
%%MMOI Calculations
%MMOI if Thin Plate Approx
Iap= 2*(1/12)*ma*(dimA(1)^2+dimA(2)^2)+ma*(dimA(1)^2/4);
Ibp= 2*(1/12)*mb*((dimB(1)+armwidth)^2+dimB(2)^2)+mb*(dimB(1)^2/4);
Icp= mc*((1/12)*dimC(1)^2+(dimB(1)+dimC(1)*cos(theta))^2+(dimC(1)*sin(theta))^2); %ThinPlate
%MMOI if Slender Rod Approx
Ias= 2*ma*(1/3)*dimA(1)^2;
Ibs= 2*ma*(1/3)*(dimB(1)+armwidth)^2;
Ics= mc*((1/12)*dimC(1)^2+(dimB(1)+dimC(1)*cos(theta))^2+(dimC(1)*sin(theta))^2);
%MMOI about pinned point O
Iop=Iap+Ibp+Icp; %Thin Plate
Ios=Ias+Ibs+Ics; %Slender Rod
%%Angular Acceleration of Chipper
alphap=(F*H)/(Iop);%Thin Plate
alphas=(F*H)/(Ios);%Slender Rod
%%Acceleration of J and G
%J is point halfway down bar C at 45∫
%G is point at bottom point of bar C at 45∫
aGp= alphap*[dimC(1)*sin(theta);dimB(1)+dimC(1)*cos(theta)]; %Thin Plate
aGs= alphas*[dimC(1)*sin(theta);dimB(1)+dimC(1)*cos(theta)]; %Slender Rod
aJp= alphap*[dimC(1)/2*sin(theta);dimB(1)+dimC(1)/2*cos(theta)]; %Thin Plate
aJs= alphas*[dimC(1)/2*sin(theta);dimB(1)+dimC(1)/2*cos(theta)]; %Slender Rod
%%Force Calculation at chip location
disp('forces=');
disp('forceoutGp forceoutGs');
disp('forceoutJp forceoutJs');
forces=[norm(aGp)*(ma+mb+mc) norm(aGs)*(ma+mb+mc); norm(aJp)*(ma+mb+mc) norm(aJs)*(ma+mb+mc)];
% forceoutGp=norm(aGp)*(ma+mb+mc);
% forceoutGs=norm(aGs)*(ma+mb+mc);
% forceoutJp=norm(aJp)*(ma+mb+mc);
% forceoutJs=norm(aJs)*(ma+mb+mc);