TensegrityAerialVehicleCollisionSim/problem_setup.py at main · muellerlab/TensegrityAerialVehicleCollisionSim · GitHub

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"""
With the same mass budget for tensegrity and propeller guard,
compare the max stress in the system during the process of an external hit.
"""
class design_param():

    def __init__(self,s=1.0):
        #s: scaling factor
        s2 = s*s
        s3 = s2*s

        self.mStructure = s3*50/1000.0 #[kg] mass of the protection structure
        self.mQuad = s3*250/1000.0 #[kg] mass of the quadcopter

        propInch = s*2.5 # 2.5in propeller diameter
        self.propR = propInch*(25.4)/(2*1000) #[m], radius of propeller
        self.propNum = 4 # Vehicle with 4 propellers

        # rod
        self.rRho = 2000 #[kg/m^3] density of carbon fiber
        self.rE = 32e9 #[Pa] Young's modulus of carbon fiber
        self.rUS = 3.5e9 #[Pa] Ultimate strenth of carbon fiber "https://dragonplate.com/what-is-carbon-fiber"

        # string
        self.sRho = 1150; # [kg/m^3] density of nylon string
        self.sE = 4.1e9 #[Pa] Young's modulus of string
        self.sD = s*1e-3  #[m] diameter of string
        self.gamma_m = 20 # ratio between mass of rod and string
        self.sPreT = 20  # [N] string pre-tension force

        """
        Two ways to design vehicles:
        0: Given propeller size, assume that the propeller placement is symmetrical, find shortest rod length that can enclose it.
        Meanwhile, the prop guard protects the same vehicle put on tensegrtiy
        1: Given propeller size, find the shortest tensegrity that can hold it without the symmetrical assumption.
        Meanwhile, the prop guard is the smallest possible design to frame the propellers so they don't hit each other.
        """
        self.designCase = 1

        """
        Two ways to model damping in the system:
        0: pair each stiffness member with a critical damper
        1: specify damping for string, rod and joints
        """
        self.dampingCase = 0
        if self.dampingCase == 1:
            self.dString = 1000 #[N/(m/s)]
            self.dRod = 1000 #[N/(m/s)]
            self.dJoint = 0.02 #[Nm/(rad/s)] Rotational damping constant
        return