In this paper we present a novel signal processing algorithm accompanied with an array structure for audio signal localization and surveillance in three dimensional space. This method, which has similarities to the eye structure, consists of a novel hemispherical microphone array with microphones on the shell and one microphone in the sphere center. A signal processing scheme utilizes parallel creation of a special closeness function for each microphone direction on the shell. Contrary to traditional algorithmic sound source localization techniques, our method is based on some simple parallel mathematical calculations in the time domain; therefore it can be easily implemented on a custom designed integrated circuit.

An indirect, self-calibrating, easy to install, and robust joint angle sensing method for heavy-duty manipulators is presented in this paper. This method is suitable for the harsh working environment of these machines where conventional contact-type angle sensors cannot be deployed, or problems are associated with their use. The approach is based on processing the outputs of a pair of biaxial accelerometers placed very close to the joint axis on the adjacent links. In the proposed technique, joint angles are obtained without integrating the accelerometer outputs to avoid measurement error accumulation over a long period of time. Two calibration procedures are also described for accelerometers to ensure the accuracy of their measurements. The experimental results attest to the efficiency and accuracy of the new angle sensing mechanism.

A novel yet simple approach for experimental determination of the link (mass and inertia-related) parameters and friction coefficients is developed for a typical excavator arm. The parameters are needed for indirect measurement of the external forces, compensation for the link weights in the operator's hand in a force-feedback teleoperation setup, impedance control of the arm, simulation of the manipulator dynamics, and model-based fault detection. Treating the machine arm as an open kinematic chain, its dynamic equations are presented symbolically. The static torque equations are derived from these equations and the gravitational parameters are defined accordingly. A new method for decoupled estimation of the gravitational parameters from static experiments is presented. Furthermore, the arm dynamics are expressed in a form which is linear in the inertia and friction-related parameters. The results obtained show that the identified model predicts the joint torques, in both static and dynamic conditions, with a very good accuracy.

In order to facilitate the testing and evaluation of control strategies and operator environments designed for heavy duty hydraulic machines, an excavator simulator has been developed and is described in this paper. The simulator comprises an impedance model of the excavator arm, a model for the bucket-ground interaction forces, a graphical environment and a haptic interface. This paper describes the simulator components and their integration.

This paper addresses issues of transparency and implementation of dual hybrid teleoperation. A method for automatically adjusting the master and slave impedances to match stiff and soft environments and to interpolate in between them is presented and evaluated using simulations. The application of this technique to the force-feedback control of a mini-excavator is also presented and discussed with supporting experimental results.

Gravitational and friction terms play an important role in achieving high performance control of heavy-duty hydraulic machines, such as excavators. In this paper, a new approach for decoupled estimation of the gravitational parameters is presented. Static experiments are carried out with an instrumented computer-controlled mini excavator to estimate the gravitational parameters. Load pins are used for indirect measurement of the joint torques from cylinder reaction forces. It is investigated via experiments that bucket payload can be estimated with a 5% accuracy. Furthermore, direct measurement of the actuators' friction shows that considerable amount of static friction exists inside the cylinders that cannot be neglected.