public void enableMotor(boolean enable, float targetVelocity, float maxMotorImpulse) {
        ((HingeConstraint) constraint).enableAngularMotor(enable, targetVelocity, maxMotorImpulse);
    }
Enables the motor.
@param enable if true, motor is enabled.
@param targetVelocity the target velocity of the rotation.
@param maxMotorImpulse the max force applied to the hinge to rotate it.
jme3-jbullet/src/main/java/com/jme3/bullet/joints/HingeJoint.java