classdef MyControllerSubsystem < HybridSubsystem
% A controller for a bouncing ball modeled as a HybridSubsystem subclass.
    properties
        ...
    end
    properties(SetAccess = immutable)
        % The indices for each component in the state vector.
        p_ndx = 1; % index of the strength of the impulse at the next jump.
        tau_ndx = 2; % index of the controller timer.
        target_period = 2.0;
    end
    
    methods
        function obj = MyControllerSubsystem() % Constructor.
            state_dim = 2;
            input_dim = 1;
            output_dim = 1;
            output_fnc = @(x) x(1); 

            % Call the constructor of the superclass 'HybridSubsystem' to create
            % the object.
            obj = obj@HybridSubsystem(state_dim, input_dim, output_dim, output_fnc);
        end

        % To define the data (f, g, C, D) of the system, we implement 
        % the abstract functions from HybridSubsystem.m
        
        function xdot = flowMap(~, ~, ~, ~, ~)  
            % Define the value of f(x, u). 
            xdot = [0; 1];
        end

        function xplus = jumpMap(this, x, ~, ~, ~) 
            % Extract the state components and parameters:
            p = x(this.p_ndx);
            tau = x(this.tau_ndx);
            tau_ref = this.target_period;
            % Define the value of g(x, u): 
            xplus = [max(0, p + 0.5*(tau_ref-tau)); 0];
        end 

        function inC = flowSetIndicator(~,~,~,~,~)
            inC = 1;
        end 

        function inD = jumpSetIndicator(~, ~, u, ~, ~)
            % Set 'inD' to 1 if 'x' is in the jump set and to 0 otherwise.
            inD = u;
        end
    end
end