RollResist_Viscous class

Contents

Description

This is a sub-class of the RollResist class for the implementation of the Viscous rolling resistance torque model.

This model assumes that the resistance torque dependends on the relative rotation velocity and normal force and is applied against the relative rotation.

$$M = -\hat{\omega} \mu R_{eff} \left | F_{n} \right | \left | V_{\omega} \right |$$

Notation:

$\hat{\omega}$: Relative angular velocity

$\mu$: Rolling resistance coefficient

$R_{eff}$: Effective contact radius

$F_{n}$: Normal contact force vector

$V_{\omega}$: Relative velocity due to rotation at contact point

References:

classdef RollResist_Viscous < RollResist

Public properties

    properties (SetAccess = public, GetAccess = public)
        % Contact parameters
        resist double = double.empty;   % rolling resistance coefficient
    end

Constructor method

    methods
        function this = RollResist_Viscous()
            this = this@RollResist(RollResist.VISCOUS);
            this = this.setDefaultProps();
        end
    end

Public methods: implementation of super-class declarations

    methods
        %------------------------------------------------------------------
        function this = setDefaultProps(this)

        end

        %------------------------------------------------------------------
        function this = setCteParams(this,~)

        end

        %------------------------------------------------------------------
        function this = evalTorque(this,int)
            % Needed properties
            dir = -sign(int.kinemat.vel_ang);
            res = this.resist;
            r   = int.eff_radius;
            f   = norm(int.cforcen.total_force);
            v   = norm(int.kinemat.vel_rot);

            % Total torque (against relative rotation)
            this.torque = dir * res * r * f * v;
        end
    end

end


Published with MATLAB® R2019b