Insufficient number of outputs from right hand side of equal sign to satisfy assignment.

Hello

I am new to Matlab. I am trying to execute a script which has PID modelled. There is one main script which has overall code to be simulated and another script has PID controller. I am calling the main script which will call the PID controller function .Everytime i try to execute the main sscript it throws error as

"Insufficient number of outputs from right hand side of equal sign to satisfy assignment." .

Error in simulate (line 97)

[in,controller_params] = controller(controller_params,thetadot);

the variable controller_params is a structured array.

The function defined in PID controller script is :

function c = PID()
    c = @(state, thetadot) pid_controller(state, thetadot);
end

function [inputs,state] = pid_controller(state, thetadot)
% Rest of the Code
end

I am unable to debug this error. Please help in understanding scenarios when it occurs and how do i resolve it.

Thanks

Answer 1

[Adam Danz]

To address your question, an anonymous function only returns a single output. So,

x = PID(. . .)      % This is fine, it returns 'inputs' from the pid_controller()
[x,y] = PID(. . .)  % This produces an error since 'state' cannot be returned.

Why wrap the anonymous function within a function?

This function

function c = PID()
    c = @(state, thetadot) pid_controller(state, thetadot);
end

merely returns a function handle that calls the pid_controller function. Why not just call that function directly and have access to both outputs?