Alejandro Ramirez-Serrano

Graeme N. Wilson, Alejandro Ramirez-Serrano, Qiao Sun

With quadrotor use seeing extensive growth in recent years, the autonomous control of these Unmanned Aerial Vehicles (UAVs) is an increasing relevant and intersting field. In this paper a linear state-space approach at designing a stable hover controller in the presence of disturbances is presented along with simulation of control system performance. Additionally the design of a tracking system, for linear inertial position and yaw, is presented with simulation results. The gain matrix developed for this control system is independent of the specific quadrotor parameters, meaning that this same gain matrix can be used on a wide variety of quadrotors without modification. The hover and tracking controllers designed in this paper proved to perform well in simulation under perturbation disturbances and normally distributed disturbances on the UAVs linear speeds and angular speeds.

Krispin Davies, Alejandro Ramirez-Serrano

The use of robotics in Urban Search and Rescue (USAR) is growing steadily from their initial inception during the 2001 World Trade Centre incident. Despite years of progress, the core design of robots currently in use for USAR purposes has deviated little, favoring software and control development and optimization of the basic robot template to improve performance instead. Presented here is a novel design description of the Cricket, an advanced robot with a broader range of physical capabilities than traditional USAR robots. By incorporating the tracked structure of earlier robots, appreciated for energy efficiency and robustness, into a multi-limbed walking design, the Cricket enables the use of advanced locomotion techniques. The ability to climb over obstacles many times the height of the robot, ascend vertical shafts without the assistance of a tether, and traverse rough and near vertical terrain improves the Cricket's capability to successfully locate victims in confined spaces.

Graeme N. Wilson, Alejandro Ramirez-Serrano, Mahmoud Mustafa et al.

Enabling high speed navigation of Unmanned Ground Vehicles (UGVs) in unknown rough terrain where limited or no information is available in advance requires the assessment of terrain in front of the UGV. Attempts have been made to predict the forces the terrain exerts on the UGV for the purpose of determining the maximum allowable velocity for a given terrain. However, current methods produce overly aggressive velocity profiles which could damage the UGV. This paper presents three novel safer methods of force prediction that produce effective velocity profiles. Two models, Instantaneous Elevation Change Model (IECM) and Sinusoidal Base Excitation Model: using Excitation Force (SBEM:EF), predict the forces exerted by the terrain on the vehicle at the ground contact point, while another method, Sinusoidal Base Excitation Model: using Transmitted Force (SBEM:TF), predicts the forces transmitted to the vehicle frame by the suspension.