Asses if a signal is within range (with dynamic setpoint) for last 60 seconds.

Im looking to build a model to asses if a incoming speed signal is within +/-3 km/h.

There are 2 options that are statisfactory for me: Look back every 60 seconds if the signal was in range (with setpoint speed at t=0s or t=60s) of Look back every sample if the 60 seconds before where within range.

So for example if the speed at 120 seconds is 79 km/h, I want to know if the speed from 60 until 120 was between 76 and 82. But when a 180s it is 90 km/h it has to be between 87 and 93 km/h Can anybody help me with this?

Kind Regards, Roel Geurts

Answer 1

[Prateekshya]

Hello Roel,

To achieve your goal of assessing whether an incoming speed signal is within a specified range over a moving window, you can implement a simple algorithm that processes the speed data in real-time. The idea is to maintain a moving window of the last 60 seconds of speed data and check if all values within this window are within the specified range of the current speed.

Here is a step-by-step guide on how to implement this in MATLAB:

• Collect Speed Data: Assume you have a vector speedData that contains the speed values sampled at regular intervals (e.g., every second).
• Define Parameters: windowSize (The number of samples corresponding to 60 seconds), tolerance (The allowable deviation from the current speed (e.g., ±3 km/h)).
• Process Each Sample: For each new speed value, check if all previous values within the window are within the specified range of the current speed.

Here is a MATLAB script to implement this:

% Example speed data (replace with your actual data)
speedData = [78, 79, 80, 81, 82, ... ]; % Extend this with your actual data
    
% Parameters
samplingRate = 1; % Samples per second
windowSize = 60 * samplingRate; % 60 seconds window
tolerance = 3; % ±3 km/h

% Initialize results
isWithinRange = true(size(speedData)); % Logical array to store results

% Loop over each sample starting from the window size
for t = windowSize:length(speedData)
    % Current speed at time t
    currentSpeed = speedData(t);
    
    % Extract the window of speeds
    speedWindow = speedData((t - windowSize + 1):t);
    
    % Check if all speeds in the window are within the range
    lowerBound = currentSpeed - tolerance;
    upperBound = currentSpeed + tolerance;
    
    % Check if all values are within the range
    isWithinRange(t) = all(speedWindow >= lowerBound & speedWindow <= upperBound);
end

% Display the result
for t = windowSize:length(speedData)
    fprintf('At time %d seconds, speed is %d km/h: ', t, speedData(t));
    if isWithinRange(t)
        fprintf('All speeds in the last 60 seconds are within range.\n');
    else
        fprintf('Not all speeds in the last 60 seconds are within range.\n');
    end
end

I hope this helps!