raisim::ActuatorDefinition

struct · #include <raisim/object/ArticulatedSystem/MotorOperatingRegion.hpp>

An actuator: a DC/BLDC motor with its gear. It drives one revolute or prismatic joint, and its torque is commanded at the output of the gear (ArticulatedSystem::setActuatorTorques()): the motor torque times the gear ratio.

Its motor turns at w_m = gearRatio * qdot_joint + sum_c ratio_c * qdot_c where the sum runs over its couplings. A coupling describes a motor that also turns with another joint, e.g. a knee motor whose reducer housing turns with the hip (KAIST Hound): ratio 1 on the hip. By conservation of power, the motor torque tau_m acts on the driven joint with gearRatio * tau_m (the actuator torque) and on each coupled joint with ratio_c * tau_m.

Public member functions

isValid

bool isValid() const

Returns true if the motor is valid (DcMotorParameters::isValid()), the gear ratio is positive and finite, the coupling ratios are finite and the output losses are non-negative and finite

Public attributes

name

std::string name

actuator name. ArticulatedSystem::setActuators() names an actuator without a name after its joint.

model

std::string model

model name, e.g. the name of its <actuator_model> (informational)

joint

std::string joint

name of the driven revolute or prismatic joint

gearRatio

double gearRatio

gear ratio: motor speed per unit speed of the driven joint (positive)

couplings

std::vector<ActuatorCoupling> couplings

joints other than the driven one that the motor also turns with

motor

DcMotorParameters motor

the motor inside the actuator

outputDamping

double outputDamping

viscous damping of the actuator, measured at its output [Nm s/rad]. It adds to the damping of the joint the actuator drives.

outputFriction

double outputFriction

Coulomb friction torque of the actuator, measured at its output [Nm]. It adds to the friction of the joint the actuator drives.