New control architecturebased on PXI for a 3-finger haptic device applied to virtual manipulation

To perform advanced manipulation of remote environments such as grasping, more than one finger is required implying higher requirements for the control architecture. This paper presents the design and control of a modular 3-finger haptic device that can be used to interact with virtual scenarios or to teleoperate dexterous remote hands. In a modular haptic device, each module allows the interaction with a scenario by using a single finger; hence, multi-finger interaction can be achieved by adding more modules. Control requirements for a multifinger haptic device are analyzed and new hardware/software architecture for these kinds of devices is proposed. The software architecture described in this paper is distributed and the different modules communicate to allow the remote manipulation. Moreover, an application in which this haptic device is used to interact with a virtual scenario is shown

Simulation of muscle-powered jumping with hardware-in-the-loop ground interaction

We developed a novel reverse haptic interface to augment forward dynamic simulations with real-world contact forces. In contrast with traditional haptics, in which a realworld user drives an interaction with a simulated environment, reverse haptics allows a simulated mechanism to probe the realworld environment through a force-sensing robotic manipulator. This method can implicitly extend computer models of biomechanics and robotic control with complex ground interactions. A 3-DoF manipulator and a biologically inspired musculoskeletal model were developed to test jumping performance on a diverse range of real-world substrates. Jumps were of similar height despite differences in material properties and no active muscle control. Muscle power was lower at the hip, yet total muscle work was higher, against compliant surfaces compared to stiff surfaces. Through reverse haptics, the forces of actuation, inertia and contacts could be measured simultaneously to reveal how intrinsic muscle properties may compensate for substrate dynamics

Highly programmable surface

A highly programmable electro-mechanical surface is developed using an effective array of individual pins arranged in a gridform. Each pin can be independently raised or lowered to create a wide range of contoured surfaces. It was found that as the number of elements increased. high levels of accuracy could still be achieved. however the required processing power increased logarithmically. This finding was attributed to the large amounts of data being passed. and subsequently led to a second focus; various methods of data management and flow control techniques within large-scale multi elemental systems. Results indicated a large potential for highly programmable surfaces within industry to provide a computer controlled surface for rapid prototyping. The research also revealed the potential for such a device to be used as a HID within Haptic applications.<br /

Controlling a remotely located Robot using Hand Gestures in real time: A DSP implementation

Telepresence is a necessity for present time as we can't reach everywhere and also it is useful in saving human life at dangerous places. A robot, which could be controlled from a distant location, can solve these problems. This could be via communication waves or networking methods. Also controlling should be in real time and smooth so that it can actuate on every minor signal in an effective way. This paper discusses a method to control a robot over the network from a distant location. The robot was controlled by hand gestures which were captured by the live camera. A DSP board TMS320DM642EVM was used to implement image pre-processing and fastening the whole system. PCA was used for gesture classification and robot actuation was done according to predefined procedures. Classification information was sent over the network in the experiment. This method is robust and could be used to control any kind of robot over distance

Motor shaft vibrations may have a negative effect on ability to implement a stiff haptic wall

A one degree of freedom experimental test bed is used to investigate the effects of elastic vibration in haptic devices. Strong angular vibration occurs at the motor rotor due to elastic deformation in the shaft. These vibrations occur due to large discontinuities in the virtual environment such as stiff contact which is common in haptics. Also looked at was the effect of these vibrations on stability and control. It was found that the vibrations may negatively affect the stability of the haptic device by introducing large measurement errors to the controller. The experiments investigated using different types of damping in controller feedback. Adding damping to the system whilst these elastic vibrations are present can successfully damp the system, but also tend to increase the magnitude of vibrations sometimes resulting in greater instability. Finally, a second non co-located encoder was used to try to eliminate measurement error from the system due to vibration. It was found that by simply placing the encoder closer to the link where the angle is being measured, error due to rotational flex in the shaft is eliminated. This yielded the greatest improvement in controller performance, nearly eliminating the presence of the vibrations and their effects

Real-time human action recognition on an embedded, reconfigurable video processing architecture

Copyright @ 2008 Springer-Verlag.In recent years, automatic human motion recognition has been widely researched within the computer vision and image processing communities. Here we propose a real-time embedded vision solution for human motion recognition implemented on a ubiquitous device. There are three main contributions in this paper. Firstly, we have developed a fast human motion recognition system with simple motion features and a linear Support Vector Machine (SVM) classifier. The method has been tested on a large, public human action dataset and achieved competitive performance for the temporal template (eg. “motion history image”) class of approaches. Secondly, we have developed a reconfigurable, FPGA based video processing architecture. One advantage of this architecture is that the system processing performance can be reconfiured for a particular application, with the addition of new or replicated processing cores. Finally, we have successfully implemented a human motion recognition system on this reconfigurable architecture. With a small number of human actions (hand gestures), this stand-alone system is performing reliably, with an 80% average recognition rate using limited training data. This type of system has applications in security systems, man-machine communications and intelligent environments.DTI and Broadcom Ltd