Shaniel Davrajh

A 7 DOF exoskeleton arm: Shoulder, elbow, wrist and hand mechanism for assistance to upper limb disabled individuals

This paper illustrates the mechanical structures spherical motion, kinematic matrices and achievable workspace of an exoskeleton upper limb device. The purpose of this paper is to assist individuals that have lost their upper limb motor functions by creating an exoskeleton device that does not require an external support; but still provides a large workspace. This allows for movement according to the Activities of Daily Living (ADL).

R2T2: Robotics to integrate educational efforts in South Africa and Europe

This paper presents the first cross-continental collaborative robotic event based around education. It was entitled R2T2 and it involved more than 100 children from Europe and Africa. Based on remo...

A Portable Passive Physiotherapeutic Exoskeleton

The public healthcare system in South Africa is in need of urgent attention in no small part because there has been an escalation in the number of stroke victims which could be due to the increase in hypertension in this urbanizing society. There is a growing need for physiotherapists and occupational therapists in the country, which is further hindered by the division between urban and rural areas. A possible solution is a portable passive physiotherapeutic exoskeleton device. The exoskeleton device has been formulated to encapsulate methodologies that enable the anthropomorphic integration between a biological and mechatronic limb. A physiotherapeutic mechanism was designed to be portable and adjustable, without limiting the spherical motion and workspace of the human arm. The exoskeleton was designed to be portable in the sense that it could be transported geographically. It is a complete device allowing for motion in the shoulder, elbow, wrist and hand joints. The inverse kinematics was solved iteratively via the Damped Least Squares (DLS) method. The electronic and computer system allowed for professional personnel to either change an individual joint or a combination of joints angles via the kinematic models. A ramp PI controller was established to provide a smooth response to simulate the passive therapy motion.

An automated apparatus for dynamic inspection of mass‐produced custom parts

Purpose – Quality control and part inspection add no monetary value to a product, yet are essential processes for manufacturers who want to maintain product quality. Mass‐produced custom parts require processes that are able to perform high frequency of inspection, whilst providing rapid response to unanticipated changes in parameters such as throughputs, dimensions and tolerances. Frequent inspection of these parts significantly impacts inspection times involved. A method of reducing the impact of high‐frequency inspection on production rates is needed. This paper addresses these issues.Design/methodology/approach – This paper involves the research, design, construction, assembly and implementation of an automated apparatus, used for the visual inspection of moving custom parts. Inspection occurred at user‐defined regions of interest (ROIs). Mechatronic Engineering principles are used to integrate sensor articulation, image acquisition and image‐processing systems. The apparatus is tested in a computer‐i...

Automated Visual Inspection of Moving Custom Parts

Mass produced custom parts require inspection routines that can facilitate variations in product parameters such as dimensions, tolerances, and throughputs. Quality control and inspection of these parts, and part families, need to occur at higher frequencies than batched produced parts. This higher frequency of inspection significantly impacts inspection times, and inherently, production rates. An effective, diverse, accurate, robust, and time efficient method for inspecting custom parts is therefore needed. Vision systems are a continuously evolving method of quality control and part inspection. These systems offer the potential to be exceptionally diverse and effective in their applications, and are therefore suited to inspecting custom parts. This paper details the research, design, construction and assembly of a prototype apparatus, which provided a suitable environment in which customized parts were inspected. System integration using the mechatronic engineering approach was performed to integrate vision, sensor articulation, and control systems. The apparatus was tested in a computer integrated manufacturing (CIM) cell to quantify system performance. Intelligence was incorporated into the inspection routine by performing visual inspection of only significant regions of interest (ROI). Dynamic access by the vision sensor to the various ROIs, allowed for inspection of moving parts, which lead to an increased process efficiency. The eliminated stoppage time required by typical inspection routines, allowed for preservation of specified production rates whilst increasing frequency of inspection.

Advanced quality management system for product families in mass customization and reconfigurable manufacturing

Purpose – Production of a high variety of products introduces complexities in the quality processes involved in a manufacturing system. Previous methods of quality assurance and control are not sufficient to manage the quality characteristics that are significant to each customer. Research into quality management for these environments has been isolated and segmented. No framework exists to holistically manage product quality within an unstable manufacturing environment. This paper seeks to propose a method of holistically managing product quality in a manufacturing environment with high customer input and product variety. The development of a reconfigurable inspection apparatus is discussed as a technological requirement for performing the quality control aspect of the management system.Design/methodology/approach – The quality requirements of modern manufacturing systems were established. The required flow of information for an advanced quality management system was proposed and compared to the informat...

Modular research equipment for on-line inspection in advanced manufacturing systems

The significance of inspection processes increases when producing parts with high levels of customer input. These processes must adapt to variations in significant product characteristics. Mass customisation and reconfigurable manufacturing are currently being researched as ways to respond to high levels of customer input. This paper presents the research and development of modular inspection equipment that was designed to meet the on-line quality requirements of mass customisation and reconfigurable manufacturing environments. Simulated results were analysed for application in an industrial environment. The implementation of the equipment in South Africa is briefly discussed. The research indicates that manufacturers need only invest in the required equipment configurations when they are needed for on-line inspection.

Fuzzy Logic Control for Varied Inspection for Manufacturing Lead Time Reduction - A Fuzzy Control Implementation of a Dynamic Inspection Technique to Reduce Manufacturing Lead Time.

Varied inspection is an online dynamic inspection method where the amount of parts inspected can be changed based on the quality of the part stream and characteristics of the production system. The research outlines the development of a supervisory and distributed Fuzzy Logic Controller (FLC) to perform varied inspection. The supervisory fuzzy controller was used to tune the weights of the rules used in the distributed fuzzy controller that initiates the varied inspection in quality control systems. Simulation of a single-station manufacturing cell showed that varied inspection had significantly reduced Manufacturing Lead Time (MLT) through reduced inspection, which could help manufacturers handle fluctuating demands. The contribution of the study was to illustrate the benefit of varied inspection through MLT reduction and to add flexibility to control architectures for quality control systems to aid manufacturers meet demands.

Inspection planning for customer-driven manufacturing environments with modular inspection stations

Customer-driven manufacturing environments experience frequent changes in product design which complicates the planning of inspection station layout, for minimal profit erosion. Modular inspection systems have been researched to minimize the implementation costs of inspection stations. This paper presents a solution to achieving low quality costs by considering the location and configuration of the researched modular inspection stations within a customer-driven manufacturing environment. A model was derived to minimize the Cost of Quality metric for a given set of customer requirements and inspection station configurations. The results suggested by the model were simulated and compared to the performance of the 100% and 0% inspection allocation strategies. The performance of each strategy was largely dependent on the reliability of each process involved with the assembly of the product.

Prioritization of part scheduling with modular quality control in hybrid manufacturing cells for mass customization

Researched manufacturing strategies involving Reconfigurable Manufacturing Systems (RMSs) and Computer Integrated Manufacturing (CIM) cells are limited when considering materials handling and quality control for mass production of customized parts (mass customization). Manufacturing paradigms such as Dedicated Manufacturing Systems (DMSs) and job shop are not focused on cost effectively diversifying products and services, based on variations in customer requirements. A solution to increase customer input, with respect to materials handling and quality control, is needed as part of increasing the overall product variety for mass customization. This paper details the research conducted to perform materials handling and quality control within a hybrid manufacturing cell that was designed to integrate the functionalities of RMSs and CIM technologies. The scheduling and quality requirements of a simulated environment were accommodated through the use of prioritization scheduling and modular inspection equipment in accordance with various product configurations. Customer requirements were quantified by specifying time, volume and quality constraints. The control of user defined part features was achieved through modular inspection of Regions of Interest (ROIs).