function [value,isterminal,direction] = eventRRr(t,x)

global  L1 L2 q10 q20 deltar

delta = L1*sin(x(1))+L2*sin(x(3))-(L1*sin(q10)+L2*sin(q20));

vt = -L1*x(2)*sin(x(1))-L2*x(4)*sin(x(3));

value = delta - deltar ;

isterminal = 1 ;

direction = 0 ;


% value(i) is the value of the ith event function.
% 
% isterminal(i)=1 if the integration is to terminate at a zero of this event function, otherwise, 0. 
% 
% direction(i)= 0 if all zeros are to be located (the default) 
%              +1 if only zeros where the event function is increasing
%              -1 if only zeros where the event function is decreasing