tgSpringCableActuator::Config Struct Reference

Inheritance diagram for tgSpringCableActuator::Config:

Public Member Functions
	Config (double s=1000.0, double d=10.0, double p=0.0, bool h=false, double mf=1000.0, double tVel=100.0, double mnAL=0.1, double mnRL=0.1, double rot=0, bool moveCPA=true, bool moveCPB=true)
void	scale (double sf)

Public Attributes
double	stiffness
double	damping
double	pretension
bool	hist
double	maxTens
double	targetVelocity
double	minActualLength
double	minRestLength
double	rotation
bool	moveCablePointAToEdge
bool	moveCablePointBToEdge

Detailed Description

Definition at line 51 of file tgSpringCableActuator.h.

Constructor & Destructor Documentation

tgSpringCableActuator::Config::Config	(	double	s = 1000.0,
		double	d = 10.0,
		double	p = 0.0,
		bool	h = false,
		double	mf = 1000.0,
		double	tVel = 100.0,
		double	mnAL = 0.1,
		double	mnRL = 0.1,
		double	rot = 0,
		bool	moveCPA = true,
		bool	moveCPB = true
	)

The only constructor. Parameters set the defaults for string material properties, construction properties and the motor model. Individual parameters are discussed below.

Todo:

is this the right place for this, or the constructor of this class?

Definition at line 37 of file tgSpringCableActuator.cpp.

Member Function Documentation

void tgSpringCableActuator::Config::scale

(

double

sf

)

Scale parameters that depend on the length of the simulation. Centemeter scale has been used throughout many of the demos, so those assumptions are baked into the default parameters.

Definition at line 90 of file tgSpringCableActuator.cpp.

Member Data Documentation

double tgSpringCableActuator::Config::damping

Specifies the damping (b) term in the linear force equation. Units are mass / seconds Must be non-negative. Similar to stiffness in usage

Definition at line 92 of file tgSpringCableActuator.h.

bool tgSpringCableActuator::Config::hist

Specifies whether data such as length and tension will be stored in deque objects. Useful for computing the energy of a trial.

Definition at line 107 of file tgSpringCableActuator.h.

double tgSpringCableActuator::Config::maxTens

The parameters that affect how the string can be controlled. Enforces a flat torque (force) speed curve with tgBasicActuator, and a linear torque speed curve with tgKinematicActuator Maximum tension that the motor can exert. String will not shorten if this threshold is exceeded, but the tension can still be increased by other members. Units are force (length * mass / seconds^2) Must be nonnegative.

Definition at line 123 of file tgSpringCableActuator.h.

double tgSpringCableActuator::Config::minActualLength

Actual length below which motor ceases to shorten. Units are length Must be nonnegative

Definition at line 137 of file tgSpringCableActuator.h.

double tgSpringCableActuator::Config::minRestLength

Rest length below which motor ceases to shorten Units are length Must be nonnegative

Definition at line 144 of file tgSpringCableActuator.h.

bool tgSpringCableActuator::Config::moveCablePointAToEdge

Control the automatic re-locating of cable anchor points.

When true, the default behavior, the specified attachment point of a cable is moved from the actual node location (for example, at the center of the circle at the end of a rod) to a location at the edge of the rigid body it's attached to (for example, on the edge of the circle at the end of a rod.)

If unsure, leave default, because when set to 'false', the cable will likely clip through the rod. Disabling automatic movement of anchor points is most useful for structures that need very particular cable placement. Here, cable attachment point "A" corresponds to the first of the two anchors of the spring-cable, or the "From" point in the tgcreator files. The "B" point corresponds to the second anchor location, or the "To" point in the tgcreator files.

These parameters are used in the createTgBulletSpringCable method inside the tgBasicActuatorInfo class.

Definition at line 176 of file tgSpringCableActuator.h.

double tgSpringCableActuator::Config::pretension

Specifies the amount of tension (in units of force) in the string at construction. Adjusts the rest length, Must be low enough (based on stiffness) to leave the rest length non-negitive

Definition at line 100 of file tgSpringCableActuator.h.

double tgSpringCableActuator::Config::rotation

Specifies the rotation around the face of the object its attached to. +/- PI is the most meaningful. absolute value must be < 2 * PI Units are radians.

Todo:

Is this meaningful for non-rod shapes?

Definition at line 153 of file tgSpringCableActuator.h.

double tgSpringCableActuator::Config::stiffness

Linear Hookean stiffness of the string (k). Must be non-negative. Upper limit depends on the timestep - stiffer springs will require a lower timestep. Used in Muscle2P, tensionMinLengthController, moveMotors (to enforce max force constraints) Units are mass / seconds^2

Definition at line 86 of file tgSpringCableActuator.h.

double tgSpringCableActuator::Config::targetVelocity

Maximum velocity of the motor, usage in moveMotors Units are length/seconds Must be nonnegative.

Definition at line 130 of file tgSpringCableActuator.h.

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The documentation for this struct was generated from the following files:

• core/tgSpringCableActuator.h
• core/tgSpringCableActuator.cpp