A Model-Free Approach for Accurate Joint Motion Control in Humanoid Locomotion

Abstract

Abstract:A new m odel-free approach to precisely control humanoid robot joints is presented in this article. An input-output online identification procedure will permit to compensate neglected or uncertain dynamics, such as, on the one hand, transmission and compliance nonlinear effects, and, on the other hand, network transmission delays. Robustness to parameter variations will be analyzed and compared to other advanced PID-based controllers. Simulations will show that not only good tracking quality can be obtained with this novel technique, but also that it provides a very robust behavior to the closed-loop system. Furthermore, a locomotion task will be tested in a complete humanoid simulator to highlight the suitability of this control approach for such complex systems.

Data-driven fractional PID control: application to DC motors in flexible joints

“…e.g. (Villagra et al, 2009), (Villagra and Balaguer, 2011), (Villagra and Herrero-Perez, 2011)). Remark 2.…”

“…The system to be controlled consists of a DC motor and an Harmonic Drive Transmission system. Furthermore, flexion torques due to the robot structure compliance have been taken into account (see (Villagra and Balaguer, 2011) IFAC Conference on Advances in PID Control PID'12 Brescia (Italy), March 28-30, 2012 FrPS.8…”

“…The fractional DD-PID is compared with the standard DD-PID in a scenario, where the position reference is a sinus of amplitude equal to 1 rad and frequency of 1 Hz, and a varying load τ l is applied to the flexible link (a sinusoidal of 1 Nm and 15Hz, see Villagra and Balaguer (2011) for more details) Figure 4 shows the response of the closed loop system to the sinusoidal excitation with 4 different configurations: the best PID, the best DD-PID (n = 1), the best fractional DD-PID and the best configuration (K P , K I , K D , α) for two controllers with fixed fractional derivative order (n = 0.7 and n = 1.2). Note that the optimal configuration in each case is obtained by minimizing the Integral Absolute Error (IAE) via a sequential combination of two nonlinear optimizers: Sequential Quadratic Programming and Nelder Mead.…”

Model-free control of a 3-DOF piezoelectric nanopositioning platform

“…Of special interest are the ultra-local representations [3][4] [5] because of their simplicity and direct control application. This method has been successfully used in electronic applications [10] or robotic devices [16] [17], and has been applied in delayed and nonminimum phase systems [11] [12]. In the current work, a controller based on the ultra-local representation is proposed for positioning a three-axis nanopositioning platform and it is experimentally proven its capability to handle the coupled effects between the actuation lines and the hysteresis of the piezoelectric actuators.…”

A Relay-Based Approach for Robot Motion Control With Joint Friction and Gravity Compensation

“…1 However, disturbances existing in robot joins greatly degrade the tracking performance by inducing limit cycle and steady-state error. One major source of disturbance is the frictional force related to the relative motion of robot joints.…”