Feedback Linearization-based Receding Horizon Control for KheperaIV

Code developed for the work published in "C. Tiriolo, G. Franzè, W. Lucia - A Receding Horizon Trajectory Tracking Strategy for Input-Constrained Differential-Drive Robots via Feedback Linearization - TCST 2022"

Full paper at: https://doi.org/10.1109/TCST.2022.3219298

Trajectory Tracking Problem Formulation

Consider a Khepera IV differential-drive robot subject to input constraints, i.e., limits on the admissible wheels' angular velocities, and a bounded trajectory $r(t)$. Design a feedback control law $[\omega_{R}(t),\omega_{L}(t)]^T=\phi(\left[p_c(t)^T,\theta(t)\right]^T,r(t))$ such that the tracking error $\xi(t)=r(t)-p_c(t)$ is bounded.

Prerequisites

The code was tested on Matlab 2020a environment and it requires a Khepera IV robot (see https://www.k-team.com/khepera-iv) to run. The code implements a Bluetooth client that sends velocity commands to the robot in order to make it track a desired trajectory (eight-shaped and circular tractories are currently available). For further details refer to the paper.

File Descriptions

• Khepera_iv_FL_RHC_traj_track.m: It is the main script to run in order to perform the experiment proposed in the paper.
• Khepera4.m: It represents the core of the application. It is a Matlab class that implements the main communication functionalities between the tracking controller running on Matlab and the server running on Khepera IV
• STTT_control_parameters.m: It's a Matlab class defining the parameters needed by the proposed tracking controller.
• "eight_traj_generation.m" and "circular_traj_generation.m" implements the reference trajectory, an eight-shaped and a circular one, respectively.

Demo

• Connect KheperaIV to the host machine through Bluetooth and set the right port on the script "Khepera_iv_FL_RHC_traj_track.m".
• Run the Bluetooth server on the KheperaIV side and then, run the script Khepera_iv_FL_RHC_traj_track.m

Videos

• https://www.youtube.com/watch?v=A0Tlbgr08tY&ab_channel=PreCySeGroup
• https://www.youtube.com/watch?v=L3wmg-pHx_4&list=PLh-6B_s-jPuT8RTDOJM96GXu4y1IBIeoC&ab_channel=PreCySeGroup