1) how do I create a function that monitors a variable for changes?
I am looking for some sort of operator to monitor a variable for changes and direction of change. Way back, I used VB to test if a variable has changed. They were called trigger+ve, trigger-ve, and udptrigger. My goal is to create a Text-To-Speech script that acts like a virtual flight instructor in a flight simulator. If the target altitude is 2000 feet, and the student deviates 200 feet to high, then the voice should say. "You are too high, descend to 2000 feet". For this case, I would like to monitor the variable alt_delta, which is the difference between the target altitude (target_alt) and the current indicated altitude (alt_ind). I have the code to find alt_delta, but now I want to monitor the newly created delta variable. So a trigger+ve event will occur if alt_delta moves from 198 feet to 202 feet. In this case, the trigger is satisfied, and the code will send an event to play the sound.
I have created three functions that will test the three types of triggers:
function **triggerpos** (var_test, value_test)
-- var_test is the variable to monitor, like "alt_delta"
-- value_test is the trigger point, like 200
function **triggerneg** (var_test, value_test)
function **monitor** (var_test)
So in the above example with altitude delta, the code would look like:
function monitor_alt ()
if triggerpos("alt_delta",200) and target_alt > alt_ind then
XPLMSpeakString("Check your altitude. You are too low. Climb to " ..
target_alt .. " feet.")
elseif triggerneg("alt_delta",-200) and target_alt < alt_ind then
XPLMSpeakString( "Check your altitude. You are too high. Descend to "
.. target_alt .. " feet.")
end
For the monitor, (as an example) I need to check the state of my scenario logic. This is an integer, so it is a whole number. For example:
monitor("scenario_state") and scenario_state=998
basically just asks if scenario_state has changed, and if so, did it change to a value of 998?? I don't care about what direction is changed, just that it DID change and to what value.
I searched the web for answers, but the code is all in C++ or java, and I can't understand it. Please help... I'm a newbie... Sorry.
Related
I'm simulating the operation of a railroad.
I have a table with train departure time, departure location, and arrival location data. Locations are given using longitude and latitude coordinates.
I created my rail yards on the GIS map using their coordinates.
I can make the trains depart following the schedules in the table and the correct departure location.
But I can't get them to go to the right destination.
When trying to use the moveTo block you can only indicate a single destination. In my simulator, each train will go to a different yard.
How can I perform this movement using a data table and geographic coordinates?
Some pertinent remarks:
I'm not using the rail library. I'm working in the GIS space with routes determined by Anylogic itself. I didn't design or import railroads.
For this reason, I'm using the "source" and "moveTo" blocks from the process modeling library.
In the "moveTo" block I didn't find options that allow me to use the longitude and latitude data of the destination and which are stored in the data table (as I do in the "source" block).
Whenever I try to insert some code that does this, Anylogic returns saying the error:
"Exception during discrete event execution:
root:
Non-unique value in the database!"
It is better to rather use an agent-based approach for this kind of movement instead of doing it using move to blocks. It is hard to explain here but do some more tutorial examples and you will understand. You want the agents to move at a specific time and in a process flow modelling approach unless you use delay or hold blocks agents will flow from one block to the next as soon as there is space.
Here is an example of how to do it using the agent-based approach using your setup.
I have an agent called Trem with a dynamic event to move it to a specific location.
Now we populate the dynamic events with data from the database at the start of the model using the code below.
List<Tuple> rows = selectFrom(db_table)
.list();
for (Tuple row : rows) {
//What is the start time of the movement
double timeToTripBegin = dateToTime(row.get( db_table.trip_begin_time ));
//Lets create a new movement event to trigger the movement in the future
create_MoveToLocation(timeToTripBegin,
row.get( db_table.latitude_chegada ),
row.get( db_table.longitude_chegada ));
}
These events will then trigger the required movement for us when the event executes.
I generated random values using following function :
P = floor(6*rand(1,30)+1)
Then, using T=find(P==5), I got values where outcome is 5 and stored them in T. The output was :
T =
10 11 13 14 15 29
Now, I want to calculate the mean value of T using mean(T) but it gives me following error :
error: mean(29): out of bound 1 (dimensions are 1x1) (note: variable 'mean' shadows function)
What I am trying to do is to model the outcomes of a rolling a fair dice and counting the first time I get a 5 in outcomes. Then I want to take mean value of all those times.
Although you don't explicitly say so in your question, it looks like you wrote
mean = mean(T);
When I tried that, it worked the first time I ran the code but the second and subsequent times it gave the same error that you got. What seems to be happening is that the first time you run the script it calculates the mean of T, which is a scalar, i.e. it has dimensions 1x1, and then stores it in a variable called mean, which then also has dimensions 1x1. The second time you run it, the variable mean is still present in the environment so instead of calling the function mean() Octave tries to index the variable called mean using the vector T as the indices. The variable mean only has one element, whose index is 1, so the first element of T whose value is different from 1 is out of bounds. If you call your variable something other than mean, such as, say, mu:
mu = mean(T);
then it should work as intended. A less satisfactory solution would be to write clear all at the top of your script, so that the variable mean is only created after the function mean() has been called.
I must calculate a function on EES.
Function: T(t)=((T_surface-T_infinity)*(e^(-bt)))+T_infinity
t is time and limits are between 1 and 40 second. I need calculate every seconds in 1-40.
How can I write this function in EES?
If I understand the question correctly, no differential equation should be solved, no integration, summation or the like should be carried out. Only a calculation with variation of the variable t is to be accomplished.
There are two possibilities. But first: EES is not 'key-sensitive'! So you should choose one—T or t—and the other should get another 'name'. I prefer 'tau' for time.
Parametric table
Write the equation in the equation window and aad the parameter you may have(?). Do not define 'tau'. like:
T=((T_surface-T_infinity)*(exp(-b*tau)))+T_infinity
T_surcace = 80[C]
T_infinity = 20[C]
b=3
Then open the parametic table, add the variables you want to see. At least you should take T and tau. Expand the rows of the table to 40 and enter the respective times. Then press the green play-button (top left in the table).
Duplicate function:
T_surface = 80[C]
$varinfo tau[] units='s'
b=0.1[1/s]
Duplicate i=1,40
tau[i] = i*1[s]
T[i]=((T_surface-T_infinity)*(exp(-b*tau[i] )))+T_infinity
End
T_infinity = 20[C]
$varinfo T[] units='C'
I'm trying to implement an Inertial Navigation System using an Indirect Kalman Filter. I've found many publications and thesis on this topic, but not too much code as example. For my implementation I'm using the Master Thesis available at the following link:
https://fenix.tecnico.ulisboa.pt/downloadFile/395137332405/dissertacao.pdf
As reported at page 47, the measured values from inertial sensors equal the true values plus a series of other terms (bias, scale factors, ...).
For my question, let's consider only bias.
So:
Wmeas = Wtrue + BiasW (Gyro meas)
Ameas = Atrue + BiasA. (Accelerometer meas)
Therefore,
when I propagate the Mechanization equations (equations 3-29, 3-37 and 3-41)
I should use the "true" values, or better:
Wmeas - BiasW
Ameas - BiasA
where BiasW and BiasA are the last available estimation of the bias. Right?
Concerning the update phase of the EKF,
if the measurement equation is
dzV = VelGPS_est - VelGPS_meas
the H matrix should have an identity matrix in corrispondence of the velocity error state variables dx(VEL) and 0 elsewhere. Right?
Said that I'm not sure how I have to propagate the state variable after update phase.
The propagation of the state variable should be (in my opinion):
POSk|k = POSk|k-1 + dx(POS);
VELk|k = VELk|k-1 + dx(VEL);
...
But this didn't work. Therefore I've tried:
POSk|k = POSk|k-1 - dx(POS);
VELk|k = VELk|k-1 - dx(VEL);
that didn't work too... I tried both solutions, even if in my opinion the "+" should be used. But since both don't work (I have some other error elsewhere)
I would ask you if you have any suggestions.
You can see a snippet of code at the following link: http://pastebin.com/aGhKh2ck.
Thanks.
The difficulty you're running into is the difference between the theory and the practice. Taking your code from the snippet instead of the symbolic version in the question:
% Apply corrections
Pned = Pned + dx(1:3);
Vned = Vned + dx(4:6);
In theory when you use the Indirect form you are freely integrating the IMU (that process called the Mechanization in that paper) and occasionally running the IKF to update its correction. In theory the unchecked double integration of the accelerometer produces large (or for cheap MEMS IMUs, enormous) error values in Pned and Vned. That, in turn, causes the IKF to produce correspondingly large values of dx(1:6) as time evolves and the unchecked IMU integration runs farther and farther away from the truth. In theory you then sample your position at any time as Pned +/- dx(1:3) (the sign isn't important -- you can set that up either way). The important part here is that you are not modifying Pned from the IKF because both are running independent from each other and you add them together when you need the answer.
In practice you do not want to take the difference between two enourmous double values because you will lose precision (because many of the bits of the significand were needed to represent the enormous part instead of the precision you want). You have grasped that in practice you want to recursively update Pned on each update. However, when you diverge from the theory this way, you have to take the corresponding (and somewhat unobvious) step of zeroing out your correction value from the IKF state vector. In other words, after you do Pned = Pned + dx(1:3) you have "used" the correction, and you need to balance the equation with dx(1:3) = dx(1:3) - dx(1:3) (simplified: dx(1:3) = 0) so that you don't inadvertently integrate the correction over time.
Why does this work? Why doesn't it mess up the rest of the filter? As it turns out, the KF process covariance P does not actually depend on the state x. It depends on the update function and the process noise Q and so on. So the filter doesn't care what the data is. (Now that's a simplification, because often Q and R include rotation terms, and R might vary based on other state variables, etc, but in those cases you are actually using state from outside the filter (the cumulative position and orientation) not the raw correction values, which have no meaning by themselves).
So say I have a variable, which holds a song number. -> song_no
Depending upon the value of this variable, I wish to call a function.
Say I have many different functions:
Fcn1
....
Fcn2
....
Fcn3
So for example,
If song_no = 1, call Fcn1
If song_no = 2, call Fcn2
and so forth...
How would I do this?
you should have compare function in the instruction set (the post suggests you are looking for assembly solution), the result for that is usually set a True bit or set a value in a register. But you need to check the instruction set for that.
the code should look something like:
load(song_no, $R1)
cmpeq($1,R1) //result is in R3
jmpe Fcn1 //jump if equal
cmpeq ($2,R1)
jmpe Fcn2
....
Hope this helps
I'm not well acquainted with the pic, but these sort of things are usually implemented as a jump table. In short, put pointers to the target routines in an array and call/jump to the entry indexed by your song_no. You just need to calculate the address into the array somehow, so it is very efficient. No compares necessary.
To elaborate on Jens' reply the traditional way of doing on 12/14-bit PICs is the same way you would look up constant data from ROM, except instead of returning an number with RETLW you jump forward to the desired routine with GOTO. The actual jump into the jump table is performed by adding the offset to the program counter.
Something along these lines:
movlw high(table)
movwf PCLATH
movf song_no,w
addlw table
btfsc STATUS,C
incf PCLATH
addwf PCL
table:
goto fcn1
goto fcn2
goto fcn3
.
.
.
Unfortunately there are some subtleties here.
The PIC16 only has an eight-bit accumulator while the address space to jump into is 11-bits. Therefore both a directly writable low-byte (PCL) as well as a latched high-byte PCLATH register is available. The value in the latch is applied as MSB once the jump is taken.
The jump table may cross a page, hence the manual carry into PCLATH. Omit the BTFSC/INCF if you know the table will always stay within a 256-instruction page.
The ADDWF instruction will already have been read and be pointing at table when PCL is to be added to. Therefore a 0 offset jumps to the first table entry.
Unlike the PIC18 each GOTO instruction fits in a single 14-bit instruction word and PCL addresses instructions not bytes, so the offset should not be multiplied by two.
All things considered you're probably better off searching for general PIC16 tutorials. Any of these will clearly explain how data/jump tables work, not to mention begin with the basics of how to handle the chip. Frankly it is a particularly convoluted architecture and I would advice staying with the "free" hi-tech C compiler unless you particularly enjoy logic puzzles or desperately need the performance.