Control System

In previous work done in the IST Humanoid Lab, it was shown that a 3 segment pendulum model of a humanoid robot, can be controlled to stand up using LQR.

The first step to control the humanoid motion its own stabilization. To perform this stabilization, we pretend to implement a discrete LQR (Linear Quadratic Regulator), which implement a gain matrix in a control close loop. The control system will operate at a sampling rate that is limited by the frequency of communication between the controller (PC / matlab) and robot (real or virtual). In the first approach, we consider that the contact point between the feet and the floor is a rotational joint without sensors or actuators. Thus, the point of contact with the ground only has 1 DoF, to control the stability of the robot is required only the pitch signal from the IMU.

EZPhysic Model Identification:

Applied Methodology:
Detailed information about the methodology to implement the LQR in a 3 link inverted pendulum from the suspended model is in the report Identification process.pdf.

Simulations and results:
The detailed information about the obtain data, the methods and first obtain models for the real robot and the EZPhisics, see the report EZPhysics_Model.zip.

Real Model Identification:

This approach was taken again with Jacobian robot structure.

System identification.

Model Linearization

LQR controller of EZPhysics simulation of Jacobian

LQR controller of Jacobian