The receive function waits up to N (10, 100, etc.) seconds to receive the NEXT incoming message in the stream -- it is not meant to receive the entire stream.
There are plenty of ways to receive the whole data set by repeatedly calling receive (Waits for the next message) or using the LatestMessage property (picks the last received message, can get the same message multiple times in a row if no new ones come in).
msg = receive(joint_state_sub,10);
msg = joint_state_sub.LatestMessage;
One way you could do it is in a for-loop. For example, suppose you want to receive the next 5000 messages that come in:
% Preallocate buffer of 5000 elements -- assuming there are 3 joints in this robot, hence 3 columns.
angles = zeros(5000,3);
% Loop through and receive
for idx = 1:5000
state_msg = receive(joint_state_sub,10);
angles(idx,:) = state_msg.Position;
end
By the way, it might be useful to also pick out the time stamps for each message if you want to plot these. To do this, you can use the Header portion of the message:
t_sec = state_msg.Header.Time.Stamp.Sec;
t_nsec = state_msg.Header.Time.Stamp.Nsec;
...
times(idx) = double(t_sec) + 1e-9*double(t_nsec)
- Sebastian
