Concept design of a novel tactile probe tip for down scaled 3D CMMs

Although coordinate metrology has reached a very high state of development concerning versatility and accuracy for common engineering parts, a high precision capability with nano scale resolution and accuracy is often hard to achieve when it is required to measure very small parts and features. The limiting component is the bulky probing system of traditional CMMs (coordinate measuring machines). In order to satisfy increasing demand for highly accurate geometrical measurements on small parts and small structures, a new measuring probe of high sensitivity and small geometrical dimension with low contact forces needs to be developed. In this paper, a novel probing system, which combines a FBG (Fibre Bragg Grating) embedded optical fibre tactile probe with an optical sensing technique, has been proposed. With the sensor elements integrated into the probe tip directly, the system sensitivity can be increased significantly. A preliminary theoretical analysis of the sensitivity of the FBG fibre sensor under axial and lateral end point loading has been presented and the results show that this micro scale probe has great potential to realize a resolution of 1nanometer on geometrical measurement of small parts.

A semiconductor strain gage tactile transducer

This paper describes the development of a semiconductor strain gage tactile transducer. It was designed with the goal of measuring finger forces without affecting the hand dexterity. The transducer structure was manufactured with stainless steel and has small dimensions ( 4 min diameter and I min thickness). It is light and suitable to connect to the finger pads. It has a device that prevents its damage when forces are applied. The semiconductor strain gage was used over due its small size and high sensitivity, although it has high temperature sensitivity. Theory, design and construction details are presented the signal conditioning circuit is very simple because the semiconductor strain gage sensitivity is high. It presents linear response from 0 to 100 N, 0.5 N resolution, fall time of 7.2 ms, good repeatability, and small hysteresis. The semiconductor strain gage transducer has characteristics that can make it very useful in Rehabilitation Engineering, Robotics, and Medicine.

Novel hardwired distributive tactile sensing system for medical applications

This thesis described the research carried out on the development of a novel hardwired tactile sensing system tailored for the application of a next generation of surgical robotic and clinical devices, namely a steerable endoscope with tactile feedback, and a surface plate for patient posture and balance. Two case studies are examined. The first is a one-dimensional sensor for the steerable endoscope retrieving shape and ‘touch’ information. The second is a two-dimensional surface which interprets the three-dimensional motion of a contacting moving load. This research can be used to retrieve information from a distributive tactile sensing surface of a different configuration, and can interpret dynamic and static disturbances. This novel approach to sensing has the potential to discriminate contact and palpation in minimal invasive surgery (MIS) tools, and posture and balance in patients. The hardwired technology uses an embedded system based on Field Programmable Gate Arrays (FPGA) as the platform to perform the sensory signal processing part in real time. High speed robust operation is an advantage from this system leading to versatile application involving dynamic real time interpretation as described in this research. In this research the sensory signal processing uses neural networks to derive information from input pattern from the contacting surface. Three neural network architectures namely single, multiple and cascaded were introduced in an attempt to find the optimum solution for discrimination of the contacting outputs. These architectures were modelled and implemented into the FPGA. With the recent introduction of modern digital design flows and synthesis tools that essentially take a high-level sensory processing behaviour specification for a design, fast prototyping of the neural network function can be achieved easily. This thesis outlines the challenge of the implementations and verifications of the performances.

A novel actuated digit with tactile feedback for clinical applications

This thesis describes the work carried out on the development of a novel digit actuator system with tactile perception feedback to a user and demonstrated as a master-slave system. For the tactile surface of the digit, contrasting sensor elements of resistive strain gauges and optical fibre Bragg grating sensors were evaluated. A distributive tactile sensing system consisting of optimised neural networking schemes was developed, resulting in taxonomy of artificial touch. The device is suitable for use in minimal invasive surgical (MIS) procedures as a steerable tip and a digit constructed wholly from polymers makes it suitable for use in Magnetic Resonance Imaging (MRI) environments enabling active monitoring of the patient during a procedure. To provide a realistic template of the work the research responded to the needs of two contrasting procedures: palpation of the prostate and endotracheal intubation in anaesthesia where the application of touch sense can significantly assist navigation. The performance of the approach was demonstrated with an experimental digit constructed for use in the laboratory in phantom trials. The phantom unit was developed to resemble facets of the clinical applications and digit system is able to evaluate reactive force distributions acting over the surface of the digit as well as different descriptions of contact and motion relative to the surface of the lumen. Completing control of the digit is via an instrumented glove, such that the digit actuates in sympathy with finger gesture and tactile information feedback is achieved by a combination of the tactile and visual means.

Fibre Bragg grating sensors for distributive tactile sensing

Distributive tactile sensing is a method of tactile sensing in which a small number of sensors monitors the behaviour of a flexible substrate which is in contact with the object being sensed. This paper describes the first use of fibre Bragg grating sensors in such a system. Two systems are presented: the first is a one-dimensional metal strip with an array of four sensors, which is capable of detecting the magnitude and position of a contacting load. This system is favourably compared experimentally with a similar system using resistive strain gauges. The second system is a two-dimensional steel plate with nine sensors which is able to distinguish the position and shape of a contacting load, or the positions of two loads simultaneously. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact. Issues and limitations of the systems are discussed, along with proposed solutions to some of the difficulties.

Tactile sensing with fibre Bragg gratings and neural networks

Fibre Bragg grating sensors are usually expensive to interrogate, and part of this thesis describes a low cost interrogation system for a group of such devices which can be indefinitely scaled up for larger numbers of sensors without requiring an increasingly broadband light source. It incorporates inherent temperature correction and also uses fewer photodiodes than the number or sensors it interrogates, using neural networks to interpret the photodiode data. A novel sensing arrangement using an FBG grating encapsulated in a silicone polymer is presented. This sensor is capable of distinguishing between different surface profiles with ridges 0.5 to 1mm deep and 2mm pitch and either triangular, semicircular or square in profile. Early experiments using neural networks to distinguish between these profiles are also presented. The potential applications for tactile sensing systems incorporating fibre Bragg gratings and neural networks are explored.

Distributive tactile sensing using fibre Bragg grating sensors

Two distributive tactile sensing systems are presented, based on fibre Bragg grating sensors. The first is a onedimensional metal strip with an array of 4 sensors, which is capable of detecting the magnitude and position of a contacting load. This system is compared experimentally with a similar system using resistive strain gauges. The second is a two-dimensional steel plate with 9 sensors which is able to distinguish the position and shape of a contacting load. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact.

Fibre Bragg grating sensors for distributive tactile sensing

Distributive tactile sensing is a method of tactile sensing in which a small number of sensors monitors the behaviour of a flexible substrate which is in contact with the object being sensed. This paper describes the first use of fibre Bragg grating sensors in such a system. Two systems are presented: the first is a one-dimensional metal strip with an array of four sensors, which is capable of detecting the magnitude and position of a contacting load. This system is favourably compared experimentally with a similar system using resistive strain gauges. The second system is a two-dimensional steel plate with nine sensors which is able to distinguish the position and shape of a contacting load, or the positions of two loads simultaneously. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact. Issues and limitations of the systems are discussed, along with proposed solutions to some of the difficulties. © 2007 IOP Publishing Ltd.

Distributive tactile sensing using fibre bragg grating sensors

Two distributive tactile sensing systems are presented, based on fibre Bragg grating sensors. The first is a one-dimensional metal strip with an array of 4 sensors, which is capable of detecting the magnitude and position of a contacting load. This system is compared experimentally with a similar system using resistive strain gauges. The second is a two-dimensional steel plate with 9 sensors which is able to distinguish the position and shape of a contacting load. This system is compared with a similar system using 16 infrared displacement sensors. Each system uses neural networks to process the sensor data to give information concerning the type of contact.

In step

In Step was a wearable artwork consisting of a pair of embroidered foot bandages and an actuator ‘cushion’ embedded with 15 electromechanical actuator pistons. The bandage was embedded with woven, soft and flexible fabric sensors - interconnected with metallic connecting threads, fasteners and a wireless interface (in a final form). When wrapped around a foot and lower leg the sensors sat on the ball of the toes and heel. This ‘wearable interface’ was then connected wirelessly to a soft sculptural form, which employed actuators to tap gently in response to the qualities of the walk detected by the soft sensors. In this way the ‘tread qualities’ of the walker could then be felt by someone else holding this device against their stomach – thereby allowing pairs of participants to ‘feel’ the tactile qualities of the other's walk. The work was presented both as a working object and via a short videorecorded performance.----- In Step generated innovative new approaches to interface and sensor embedded clothing/footware whilst also creating an evocative vehicle to comment upon contemporary Post Colonial theories of weight and groundedness – particularly the psycho-geographical ‘separation’ from the landscape that inspired Paul Carter’s “environmentally grounded poetics”. The work’s final form also suggested critical new directions for responsive clothing and footwear for the emerging genre of smart textiles.

A forward and backward secure key management in wireless sensor networks for PCS/SCADA

Process Control Systems (PCSs) or Supervisory Control and Data Acquisition (SCADA) systems have recently been added to the already wide collection of wireless sensor networks applications. The PCS/SCADA environment is somewhat more amenable to the use of heavy cryptographic mechanisms such as public key cryptography than other sensor application environments. The sensor nodes in the environment, however, are still open to devastating attacks such as node capture, which makes designing a secure key management challenging. In this paper, a key management scheme is proposed to defeat node capture attack by offering both forward and backward secrecies. Our scheme overcomes the pitfalls which Nilsson et al.'s scheme suffers from, and is not more expensive than their scheme.

Fusion of in-vehicle sensor data to develop Intelligent Driver Training System (IDTS)

The over represented number of novice drivers involved in crashes is alarming. Driver training is one of the interventions aimed at mitigating the number of crashes that involve young drivers. To our knowledge, Advanced Driver Assistance Systems (ADAS) have never been comprehensively used in designing an intelligent driver training system. Currently, there is a need to develop and evaluate ADAS that could assess driving competencies. The aim is to develop an unsupervised system called Intelligent Driver Training System (IDTS) that analyzes crash risks in a given driving situation. In order to design a comprehensive IDTS, data is collected from the Driver, Vehicle and Environment (DVE), synchronized and analyzed. The first implementation phase of this intelligent driver training system deals with synchronizing multiple variables acquired from DVE. RTMaps is used to collect and synchronize data like GPS, vehicle dynamics and driver head movement. After the data synchronization, maneuvers are segmented out as right turn, left turn and overtake. Each maneuver is composed of several individual tasks that are necessary to be performed in a sequential manner. This paper focuses on turn maneuvers. Some of the tasks required in the analysis of ‘turn’ maneuver are: detect the start and end of the turn, detect the indicator status change, check if the indicator was turned on within a safe distance and check the lane keeping during the turn maneuver. This paper proposes a fusion and analysis of heterogeneous data, mainly involved in driving, to determine the risk factor of particular maneuvers within the drive. It also explains the segmentation and risk analysis of the turn maneuver in a drive.

Towards continuous surveillance of fruit flies using sensor networks and machine vision

In Australia, the Queensland fruit fly (B. tryoni), is the most destructive insect pest of horticulture, attacking nearly all fruit and vegetable crops. This project has researched and prototyped a system for monitoring fruit flies so that authorities can be alerted when a fly enters a crop in a more efficient manner than is currently used. This paper presents the idea of our sensor platform design as well as the fruit fly detection and recognition algorithm by using machine vision techniques. Our experiments showed that the designed trap and sensor platform is capable to capture quality fly images, the invasive flies can be successfully detected and the average precision of the Queensland fruit fly recognition is 80% from our experiment.