heatctrl.m

Matlab学习课件

% Simulation of heater control using a PWM actuation
% This system uses minimum latency scheduling
% File: heatcntrl.m
% Created 8/4/95 by DM Auslander
%  Based on pwm_samp.m

heatglbl  % Read in global definitions -- because each function
	%in Matlab requires a new file, this is a more compact
	%way to share variables

% System setup and initialization
% Put initial values for all variables here

% Simulation parameter values (time units are seconds)
tfinal = 20;
%del_t = 0.02;	% Use del_t=0.01 for pwm_period=0.5; 0.02 for 1.0
del_t = 0.0115;	% For calibrated time
del_tsim = 0.06;
ept = del_t / 100;	% Used to check for round-off errors

% Use this to control the number of output values
t_outint = del_t * 5;	% Time interval for outputs
		% This is particularly important for the student edition!
nouts = ceil(tfinal / t_outint);
yout = zeros(nouts + 1,4); % Set this up for proper output dimension
tout = zeros(nouts + 1,1);
t_outnext = 0;	% Time at which next output will be copied
iout = 1;		% Index for outputs
tstep = 0;		% Running time

% Set up the options for the differential equation solver
% (if one is being used). The lines given here use a modified
% version of "Odesuite"
ode_opts = odeset('refine',0,'reltol',1.e-3);	% Differential solver options

% Make up a task list using the string-matrix function, str2mat()
% Note that this can only take 11 strings in each call, so it must be called
% multiple times for more than 11 tasks
% Each name represents a function (file) for that task

%t1 = str2mat('heat_pid','heat_sup');  % Continuous tasks
%t1 = str2mat('heat_pid','heat_sup','heat_pwm');  % Continuous tasks
t1 = str2mat('heat_pid','heat_sup','dummy1','dummy1','dummy1');  % Continuous tasks
tasks_con = str2mat(t1);
nncon = size(tasks_con);
ntasks_con = nncon(1);		% Number of rows

t1 = str2mat('heat_pwm'); % Intermittent tasks
tasks_int = str2mat(t1);
nnint = size(tasks_int);
ntasks_int = nnint(1);		% Number of rows
%ntasks_int = 0;

% Initial variable values
duty_cycle = 0;
pwm_out = 0;
Tpid_delt = 1; % How often the PID control task should run
Theat_pid = 0; % Next run time for command
Kp = 3.5;	% Controller gains
Ki = 4.0;
Kd = 0.0;
temp_soak = 0.5;	% Processing temperature
temp_set = 0;		% Initialization
soak_time = 5.0;
pwm_period = 1;  % Two periods are used for this sample:  0.5 and 1
pwm_out = 0;
duty_cycle = 0;

% Variables associated with measuring pwm duty cycle
kdc = 0;
start_pwm = -1;
meas_duty = [];
start_off = -100;

% Set initial states
Sheat_pid = 0;	% A state of 0 is used as a a flag to the
Spwm_gen = 0;	% state to do whatever initialization it needs
Sheat_sup = 0;

% Target system parameters
Kin = 2;	% Conversion from pwm_out 
Kout = 1.5;	% Heat loss coeffiecient
Csys = 10;		% Target system total heat capacity
temp_amb = 0;	% Ambient temperature
temp_init = 0.3;
x(1) = temp_init;	% Initial temperature
dummy1;
% Initialize all the tasks
for j = 1:ntasks_con		% Continuous tasks
	tsk = tasks_con(j,:);	% name of j-th task
	feval(tsk);	% No arguments - task takes care of state
			% and when it runs internally.
end

for j = 1:ntasks_int		% Intemittent tasks
	tsk = tasks_int(j,:);	% name of j-th task
	feval(tsk);	% No arguments - task takes care of state
			% and when it runs internally. ('Completion' isn't
			% relevant here)
end

i_audit = 1;	% Index for transition audit trail
trans_trail = [];	% Initialize transition autid trail

tic;	% Start the real-time clock
tstep = 0;
tbegin = get_time;	% Time at the beginning of simulation step

% Step out the solution
while tstep <= tfinal
	% Copy output values to the output array
	if (tstep + ept) >= t_outnext
		t_outnext = t_outnext + t_outint;	% Time for next output
		yout(iout,1) = duty_cycle;
		yout(iout,2) = pwm_out;
		yout(iout,3) = x(1);
		yout(iout,4) = temp_set;
		tout(iout) = tstep; % Record current time
		iout = iout + 1;
	end
	
	% Run the control tasks

	for j = 1:ntasks_con
		tsk = tasks_con(j,:);	% name of j-th task
		feval(tsk);	% No arguments - task takes care of state
				% and when it runs internally.
		inc_time;	% Increment time
		% Simulation stuff
		del = get_time - tbegin; % Time since last simulation
		if del >= del_tsim	% If true, do a simulation step
			tbegin = get_time;
			[tt,xx,stats] = odeeul('heat_sys',del,x,ode_opts); 
			x = xx;	% Update the state vector
		end
		for k = 1:ntasks_int
			tsk = tasks_int(k,:);	% name of k-th task
			del = get_time - tbegin; % Time since last simulation
			if del >= del_tsim	% If true, do a simulation step
				tbegin = get_time;
				[tt,xx,stats] = odeeul('heat_sys',del,x,ode_opts); 
				x = xx;	% Update the state vector
			end
			flag = 0;	% Completion flag
			while ~flag
				flag = feval(tsk);
					% Loop until task signals completion
				inc_time;	% Increment time
				del = get_time - tbegin; % Time since last simulation
				if del >= del_tsim	% If true, do a simulation step
					tbegin = get_time;
					[tt,xx,stats] = odeeul('heat_sys',del,x,ode_opts); 
					x = xx;	% Update the state vector
				end
			end
		end  % k-loop
	end % j-loop
	
	tstep = get_time;	% Update time
end
% Record the final output values
yout(iout,1) = duty_cycle;
yout(iout,2) = pwm_out;
yout(iout,3) = x(1);
yout(iout,4) = temp_set;
tout(iout) = tstep;

%Trim the output arrays in case there are extra rows
% (which can happen in real time where the time increment is
% not known)
nry = size(yout,1);
if nry > iout
	yout = yout(1:iout,:);
	tout = tout(1:iout);
end

% Plot results
subplot(2,1,1);	% Top subplot
plot(tout,yout(:,1),'k--');
ylabel('Duty Cycle');
subplot(2,1,2); % Bottom subplot
plot(tout,yout(:,3),'r',tout,yout(:,4),'k--');
ylabel('Temperature');
xlabel('Time');