Robust tuning of robot control systems

The computed torque control problem is examined for a robot arm with flexible, geared, joint drive systems which are typical in many industrial robots. The standard computed torque algorithm is not directly applicable to this class of manipulators because of the dynamics introduced by the joint drive system. The proposed approach to computed torque control combines a computed torque algorithm with torque controller at each joint. Three such control schemes are proposed. The first scheme uses the joint torque control system currently implemented on the robot arm and a novel form of the computed torque algorithm. The other two use the standard computed torque algorithm and a novel model following torque control system based on model following techniques. Standard tasks and performance indices are used to evaluate the performance of the controllers. Both numerical simulations and experiments are used in evaluation. The study shows that all three proposed systems lead to improved tracking performance over a conventional PD controller

A new damping modelling approach and its application in thin wall machining

In this paper, a new approach to modelling the damping parameters and its application in thin wall machining is presented. The approach to predicting the damping parameters proposed in this paper eliminates the need for experiments otherwise used to acquire these parameters. The damping model proposed was compared with available damping models and experimental results. A finite element analysis and Fourier transform approach has been used to obtain frequency response function (FRF) needed for stability lobes prediction. Several predicted stable regions using both experimental and numerical FRF’s for various examples gave a good comparison.Engineering and Physical Sciences Research Counci

Characterization of metal cutting dynamics. Final report

A Hardinge CNC lathe has been fitted with sensors and a data acquisition system for the measurement, processing and storage of accelerations and forces associated with orthogonal cutting. This system has been completely validated. Orthogonal cutting experiments were designed in order to study the effects of critical cutting parameters on machining dynamics. Three major experimental sets were conducted. In the first set the depth of cut was increased in a stepwise fashion, while the workpiece surface speed, the spindle speed, and the tool feedrate were maintained invariant. In the second and third sets, the spindle speed and feedrate were varied, respectively, while maintaining all the other parameters invariant. In total over two hundred orthogonal cutting experiments were performed. In each experiment, the two non-zero components of the tool acceleration and the two non-zero components of the cutting force were measured. Despite high noise levels, mutual information calculations with smoothing kernels and false nearest neighbor algorithms proved to be sufficiently robust to provide upper bounds on attractor dimension for all fifty data sets studied. These results prove that the infinite dimensional cutting process has an associated attractor of dimension {le} 4. This result is important as a guide to model construction. An analysis of the power spectral sideband structure proved that sideband spacing is identical to the turning frequency. This result was further substantiated through envelope detection techniques. A linear delay model was shown to emulate the experimental power spectrum and possess predictive capacity

A Note on the History of the Jefferson Manuscript Draught of the Declaration of Independence in the Library of the American Philosophical Society

Volume: 37Start Page: 88End Page: 10

Stochastic single vehicle routing with a predefined customer sequence and multiple depot returns

We study the routing of a single vehicle that delivers multiple products under stochastic demand. Specifically, we investigate two practical variations of this problem: (i) The case in which each product type is stored in its dedicated compartment in the vehicle, and (ii) the case in which all products are stored together in the vehicle's single compartment. Suitable dynamic programming algorithms are proposed to determine the minimum expected (routing) cost for each case. Furthermore, the optimal routing policy is derived by developing appropriate theorems. The efficiency of the algorithms is studied by solving large problem sets.Logistics Stochastic vehicle routing Multiple product delivery Dynamic programming

Stochastic single vehicle routing problem with delivery and pick up and a predefined customer sequence

In this paper we study the routing of a single vehicle that delivers products and picks up items with stochastic demand. The vehicle follows a predefined customer sequence and is allowed to return to the depot for loading/unloading as needed. A suitable dynamic programming algorithm is proposed to determine the minimum expected routing cost. Furthermore, the optimal routing policy to be followed by the vehicle's driver is derived by proposing an appropriate theorem. The efficiency of the algorithm is studied by solving large problem sets.Logistics Stochastic vehicle routing Pick up and delivery Dynamic programming

The record of the celebration of the two hundredth anniversary of the birth of Benjamin Franklin,

Edited by Dr. I. Minis Hays.Vols. 2-6: Calendar of the papers of Benjamin Franklin in the library of the American philosophical society. Ed. by I. Minis Hays.Mode of access: Internet.SML,FRA 401 1906a: Binding variant

The record of the celebration of the two hundredth anniversary of the birth of Benjamin Franklin, under the auspices of the American Philosophical Society, held at Philadelphia for promoting useful knowledge, April the seventeenth to April the twentieth, A.D. nineteen hundred and six.

Vol.