A new global isotropy index (GII) is proposed to quantify the configuration independent isotropy of a robot's Jacobian or mass matrix. A new discrete global optimization algorithm is also proposed to optimize either the GII or some local measure without placing any conditions on the objective function. The algorithm is used to establish design guidelines and a globally optimal architecture for a planar haptic interface from both a kinematic and dynamic perspective and to choose the optimum geometry for a 6-DOF Stewart Platform. The algorithm demonstrates consistent effort reductons of up to six orders of magnitude over global searching with low sensitivity to initial conditions.

A methodology was developed using the sound signal based on wavelet analysis and self-organizing neural network (NN) to monitor cutting accuracy in an extremely noisy machining process. Sawing experiments were conducted under different levels of feed speed, depth of cut, and rotation speed to monitor the longitudinal waviness of sawn samples using laser displacement sensors as an index of cutting accuracy and sawing deviation. The sound of the cutting and idling processes was recorded using a microphone. The acquired acoustic signals were pre-processed using the wavelet de-noising method for background noise elimination. As the signal still encompasses the low-frequency components corresponding to the idling process (machine motor, saw vibration, etc.), a systematic wavelet thresholding method was applied to the coefficients of the decomposed signal at different levels to discard the sound signal components associated with the idling process. Inverse wavelet transform was then applied to make a synthesized signal from the original one. Different features were extracted from the original and synthesized signals and used to train a self-organizing NN. Group method of data handling (GMDH) NN was utilized for predicting the waviness from the sensory features. The GMDH model trained with features extracted from the synthesized signal outperformed the one trained with the original signal features. The results suggested that employing the proposed wavelet-based methodology enables the acoustic signal to be used in monitoring the manufacturing processes in an extremely noisy environment. Self-organizing NN was shown to have a promising performance without facing the difficulties in finding the network optimal architecture, which is a typical challenge in the conventional back-p