摘要:

Nonlinear feedback control algorithms for manipulators utilise the complete (coupled and nonlinear) dynamic model to decouple the robot joints. In this framework, we present a comparative evaluation of the computed-torque and direct-design control algorithms, and outline the practical problems introduced by modelling inaccuracies, unmodelled dynamics and parameter errors. We then formulate the α-computed-torque nonlinear feedback control algorithm which is robust in the presence of the aforementioned error sources. Numerical experiments with cylindrical robots confirm the robustness and applicability of our α-computed-torque algorithm.

DOI:10.1049/ip-d.1985.0026

出版商:IEE    

年代:1985

数据来源: IET

摘要:

This paper outlines a multivariable control system design approach for industrial robots based on computer-aided frequency-response techniques. A configuration-dependent multivariable controller is derived which is shown to be related closely to various nonlinear decoupling controllers proposed in the literature. Simulation of the robot and controller is used as a design aid to assess whether typical performance criteria are met in the face of constraints. It is noted that, in the nonlinear regime of actuator saturation, the multivariable controller can be suitably modified to maintain performance. The stability and robustness of the total system are discussed. Implementation experience reveals the necessity of incorporating integral action into controller designs on final convergence to a setpoint. The final controller is demonstrated to work well in simulation and in hardware implementation. Studies on the hardware system yield further robustness conclusions.

DOI:10.1049/ip-d.1985.0027

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The author has previously presented work concerned with the automatic control of industrial-type robots [1, 2]. The quite formidable problems of cross coupling of dynamics, extensive nonlinearities, unknown parameter changes and modelling errors were overcome by a technique of model reference adaptive control. Furthermore, the author has shown [3] that this technique is applicable to most types of industrial robots (according to a classification of Coiffet [4]). In this paper, we show that a simplification of the model of the robot yields a particularly attractive form of model reference adaptive controller, whereby the strategy for each link is decoupled from all the other strategies. The main advantages in this are that the controller design is much simpler than before, and that the amount of computation is reduced. Simulation studies support the view that the loss of information induced by thea priorichoice of a simple robot model has little effect on the performance of the closed-loop system.

DOI:10.1049/ip-d.1985.0028

出版商:IEE    

年代:1985

数据来源: IET

摘要:

This paper considers the inspection of circular objects. Template matching forms a competitive approach for inspecting these products, but radial histograms are found to be especially useful whenever products are nearly symmetric. Various methods of renormalising radial histograms are compared, with particular reference to accuracy and resolution. It is shown that radial histogramming is valuable for checking quickly for various defects, and that it can lead to increased accuracy of radial measurement. Its capabilities depend strongly on the previous accurate location of the centres of circular regions: the Hough transform approach is well adapted to this purpose.

DOI:10.1049/ip-d.1985.0029

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The use of robotic welding in industry is well documented. Further automation will involve the use of sensors with feedback to carry out such tasks as seam tracking or weld penetration monitors. The paper describes a seam tracker for TIG welding. It uses a standard black and white television camera to view the light reflected from the components being welded. The light source is a halogen tungsten lamp. High-speed digitisation using a microcomputer enables rapid correction for any misalignment. All the components used are standard, so that a low-cost system may be produced.

DOI:10.1049/ip-d.1985.0030

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The paper describes the elements of a flexible assembly system which is being constructed to investigate methods of integrating robots within production systems. Also described are the features of ‘intelligent’ interfaces which have been designed to allow robots and machines to be linked, via a local area network, to supervisory computers. The interfaces are based on the ISO model of open-system connection and include MAP data packets so that they offer a standard and transferable solution to the problem of integrating computer-based shop-floor and management functions.

DOI:10.1049/ip-d.1985.0031

出版商:IEE    

年代:1985

数据来源: IET

摘要:

Increasingly there is a need to equip robots with intelligent sensing so that they can detect and compensate for discrepancies between what they have been taught and what is required in the real world. This enables them to allow for variations in the immediate manufacturing environment (e.g. component variation) and also relaxes the requirements for precision in the hardware and the accuracy of teaching. The authors describe their work on semiautonomous adaptable units for use in assembly. The units are of integral design equipped with sensors, local processing power and local actuation. They are intended to be placed on the machinery and automatic assembly, which may have either hard-automation or robotic form.

DOI:10.1049/ip-d.1985.0032

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The automation of making-up operations for the garment industry is discussed in general terms together with the problems of assembling pliable materials into complex three-dimensional shapes. The paper describes work, being undertaken by the Department of Mechanical Engineering at Loughborough University of Technology, on the application of sensor-based, intelligent controls for robotic assembly of flexible, knitted components.

DOI:10.1049/ip-d.1985.0033

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The rapid introduction of the industrial robot into the manufacturing environment has created a need for new safety technology. Most companies using robots have embarked on safety programmes depending on personnel training, preventive maintenance and perimeter barriers, but these methods do not address the issue of personnel required to be close to a robot during teach-mode programming, maintenance and trouble-shooting. The paper discusses results of a research project underway at Rensselaer Polytechnic Institute to develop a computer-controlled sensor system that will monitor the working envelope of a robot; and, if a dangerous situation occurs, will cause the robot to take corrective action to avoid personnel injury or damage to the robot or equipment. The sensor technologies investigated include microwave, ultrasound, infra-red and capacitive.

DOI:10.1049/ip-d.1985.0034

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The paper reports results of the practical application of the self-organising controller to the simultaneous control of two interacting joints of a robot. The rationale for its use and the architecture of this heuristic fuzzy rule-based dynamic control approach are outlined. This shows it to be a relatively simple intelligent knowledge-based system capable of both learning and displaying a variable nonlinear input/output relationship. In both step response and tracking experiments the self-organising controller was found to perform better than a conventional PID controller under similar circumstances, although some tuning was required for the former system.

DOI:10.1049/ip-d.1985.0035

出版商:IEE    

年代:1985

数据来源: IET