The Oncilla Joints L1 and L2 provide the same (technical) interface, as they are both realized as servo motors on the hardware platform.
L1 represents the protraction-retraction hip joint. L2 represents the flexion-extension knee joint. Both can be controlled in position, velocity, torque and impedance and report current angle of of the motor axis and the magnetic encoder.
Simple joint space control of a L1 or L2 joint:
Oncilla oncilla; // get robot instance
L1::Ptr left_fore_hip = oncilla.getL1(LEFT_FORE); // get left fore l1 joint
JointAnglesPtr command = JointAngles::fromRad(3.14); // in radians
left_fore_hip->setJointPosition(command); // send new command
std::cout << left_fore_hip->getJointPosition()->deg(); // get position in degrees
Refer to the API documentation of rci::oncilla::OncillaL1L2 for the full technical interface of these joints.