A method for stereo-vision based tracking for robotic applications

Vision based tracking of an object using the ideas of perspective projection inherently consists of nonlinearly modelled measurements although the underlying dynamic system that encompasses the object and the vision sensors can be linear. Based on a necessary stereo vision setting, we introduce an appropriate measurement conversion techniques which subsequently facilitate using a linear filter. Linear filter together with the aforementioned measurement conversion approach conforms a robust linear filter that is based on the set values state estimation ideas; a particularly rich area in the robust control literature. We provide a rigorously theoretical analysis to ensure bounded state estimation errors formulated in terms of an ellipsoidal set in which the actual state is guaranteed to be included to an arbitrary high probability. Using computer simulations as well as a practical implementation consisting of a robotic manipulator, we demonstrate our linear robust filter significantly outperforms the traditionally used extended Kalman filter under this stereo vision scenario. © 2008 IEEE.

Countering Improvised explosive devices through a multi-point haptic teleoperation system

Improvised Explosive Devices (IEDs) are reported as the number one cause of injury and death for allied troops in the current theater of operation. Current stand-off technologies for Counter IED (CIED) tasks rely on robotic platforms that have not improved in capability over the past decade to combat the ever increasing threat of IEDs. While they provide operational capability, the effectiveness of these platforms is limited. This is because they primarily utilise video and audio feedback, and require extensive training and specialist operators. Recent operational experience has demonstrated the need for robotic systems that are highly capable, yet easily operable for high fidelity manipulation. Force feedback provides an operator with more intuitive control of a robotic system. This sense of touch allows an operator to obtain a sense of feel from a stand-off location of what the robot touches or grasps through a human-robot interface. This paper reports the design and development of a Haptically-Enabled Counter IED robotic system that was funded by the Australian Defence Force. The presented work focuses on the design methodology for the system, and provides the results of the manipulator analysis and trial outcomes.

Mathematical modelling of linear motion error for Hexarot parallel manipulators

Hexarot is a robotic manipulator that belongs to the family of axis symmetric parallel mechanisms. The robot is able to move the robot platform or tool center point in six degrees of freedom (DOF). This paper presents the kinematics model of the robot including the inverse and forward kinematics, and its time derivatives. Then using the kinematics formulations, investigation of the nonlinear motion of the Hexarot robot for a desired linear motion path is performed. For this purpose, the concept of curvature of the robot path is used for measuring the nonlinearity of the actual motion of the robot. The nonlinear motion error of the robot is analyzed for the scenario where the platform moves on a linear path between two arbitrary points of the robot workspace. The effects of different parameters on the nonlinear motion error of the mechanism are demonstrated and strategies for motions with low error values are proposed.