P. M. Taylor

Integration of A Flexible Workcell for Garment Assembly

Hull University Robotics Research Unit is currently researching into the problems involved in realising a flexible, automated garment assembly workstation. A demonstration rig, incorporating a number of robotic and assembly tasks quickly showed that a hierarchical information and downloading structure was necessary for true flexibility. This paper decribes this structure in detail, outlining the current status of this ongoing project and the further work required to establish the ideas involved in its makeup. KEYWORDS: Robotic garment assembly, flexible workcell, man machine interface, cluster/production supervisor.

Sensing in Garment Assembly

Sensing demands in the automated assembly of garments differ considerably from those encountered in rigid materials handling. Attempts to automate in an ‘open loop’ manner, assuming knowledge and consistency of all relevant fabric properties, are usually doomed to failure because such properties are likely to vary from batch to batch, with time, environmental conditions, and can be dependant on the handling history. Sensory feedback can provide information for the selection of appropriate corrective action. Various sensing strategies have been proposed for the detection of presence, position and orientation of fabric stacks and individual panels, with the aim of preparing parts for joining. These are discussed in some detail with particular emphasis on the practicalities of different means with respect to the relevant properties of the materials and the environment. The applications of sensors during sewing operations, for error recovery and for inspection purposes are also described.

Complete Garment Assembly Using Robots

This paper describes the evolution of the problem of robotic based fabric handling as seen by the Robotics Research Unit at Hull University. The third phase of the associated project, following success in ply separation and robotic sewing, is to produce a prototype robotic assembly line for a complete garment. The line is designed for assembling mens Y-fronts and ladies briefs. The project is subdivided into two dimensional component based assembly, three dimensional folding and closing operations, and a supervisory computer system to aid communication and reconfiguration.

A water hydraulic robot

The design of a novel robot is outlined. The robot has three important design features: water driven hydraulics, harmonic drive gearboxes used as differentials and a planar five-bar parallelogram mechanism. The water motor/valve characteristics are described for a pre-prototype system and these are used in a simulation of step responses which are shown to exhibit limit cycling behaviour for small step demands. These simulations agree well with experimental behaviour and have been used to aid the design of improved motors.<<ETX>>

Nonlinear control for robots with significant drive nonlinearities

This paper describes progress being made towards the computer aided design of Variable Structure type controllers for robots which exhibit significant drive nonlinearities. Results are given of the design of such a controller for a single axis, compared with the performance of the existing PID controller, and future research plans are outlined towards multi-axis control.

Sinusoidal input describing function analysis of nonlinear systems having a very general structure

An iterative method, with examples of use, is presented for describing function analysis of nonlinear systems having a very general structure.

The Design and Control of a Novel Robot Structure with Differential Drive Units

A novel robot has been designed and constructed as part of a project to develop water hydraulic systems. A planar five-bar mechanism is driven through two co-axial shafts to position the end effector anywhere within a circular working area in the horizontal plane. No end stops are required. Each shaft is driven by two Fenner 06 water motors or two rotary oil motors via a differential drive unit (DDU). This allows great flexibility over motor speeds and control strategies, in particular allowing low and zero speed output shaft movements whilst keeping the motors running at well-controllable speeds. The robot design is described with practical results from different control strategies for velocity and position control.

A low cost robot based integrated manufacturing system for the garment industry

As the rest of the world becomes more competitive so the garment manufacturing industry in the UK suffers from the effects of low cost imports. High levels of employment and high wage figures in the UK and a noisy, undesirable work environment results in the garment industry suffering from a high employment turnover. Companies in the UK are therefore being forced to consider either drops in overall output, shifts to higher cost/quality markets, or increases in the level of productivity through automation.