Linear time-invariant (LTI) controllers suffer from inherent limitations as the waterbed effect and Bode's gain-phase relationship. Reset control, a nonlinear strategy involving the reset of linear controllers, offers a potential solution to overcome these traditional LTI limitations. Based on the describing function analysis, the reset controller provides the advantage of less phase lag compared to its linear counterpart. In this study, we explore the application of the Proportional Clegg Integrator (PCI), a reset element, to replace the Proportional Integrator (PI) within the PID framework for a wire bonder, aiming to break LTI limitations and therefore improve the system's performance. However, due to the reset action of the PCI, it cannot provide a constant buffer force as the PI does to compensate for the machine's nonlinearity and external disturbances. This lack of compensation can lead to undesired limit-cycling behavior, preventing the system from achieving zero steady-state error. To address this issue, a PI is added after the PCI to form a PCI-PID framework for completely eliminating the limit cycles. To optimize the performance of the PCI within the PCI-PID framework, a tuning algorithm is proposed, leveraging the machine's frequency response function (FRF) data. Frequency-domain analytical tools, including open-loop Higher-Order Sinusoidal Input Describing Functions (HOSIDFs) and the pseudo-sensitivity function from approximate closed-loop HOSIDFs, are applied during the optimization process. However, the introduction of the PI for the PCI leads to a trade-off, causing a reduction in phase margin or a decrease in the nonlinear benefits gained from the PCI. To overcome this limitation, a novel integrator called the Generalized First Order Reset Element-based Integrator (GFbI) is introduced. The GFbI, as a single integrator, has the ability to internally incorporate a PI within its structure, allowing it to achieve the desired zero steady-state error without externally introducing an additional linear integrator. This unique characteristic allows the GFbI to attain zero steady-state error, without being confined by the limitations associated with introducing an additional PI. Furthermore, the GFbI can be automatically tuned based on a proposed constraint regarding the number of reset instants, permitting the use of machines' FRF data. Finally, with the novel GFbI structure and its tuning algorithm, the experimental data obtained from an industrial motion platform demonstrates a decrease (30.8%) in the root-mean-square of the settling error.

Linear time-invariant controllers are undoubtedly the most popular type of regulators used in industrial applications, with the overwhelming majority of companies employing them. The reason is mainly given by their simple design methods. In particular, frequency domain predictive performance analysis and stability methods allow the use of loopshaping techniques. Nevertheless, inherent limitations affecting linear controllers pose constraints on their performance that can only be overcome through the adoption of nonlinear control schemes. Promising findings in recent literature suggest that with reset control, a nonlinear control technique, it is possible to overcome these limitations. At the same time, reset control could also potentially allow the use of straightforward design techniques, thus making it suitable for industrial applications. The main goal of this work is to bring together the different concepts scattered in literature, in order to initialize the construction of a general framework for the design and analysis of reset controllers suitable for an industrial setting. Tuning guidelines for different structures using two classes of reset controllers, the first order reset element and the proportional Clegg integrator, were presented. Two frequency domain methods, namely open-loop higher order sinusoidal input describing functions (HOSIDFs) and pseudosensitivities computed through analytically derived (approximate) closed-loop HOSIDFs, were effectively applied to predict steady-state performance. Stability was (when possible) analysed through the frequency domain Nyquist stability vector method, which could also be implemented in the design process. The frequency domain analysis methods allowed the use of loopshaping techniques similar to LTI control for the design of reset controllers. The controllers, implemented digitally on an ASM Pacific Technology wire bonding machine, show that through reset control a significant decrease in the root mean square of the settling error compared to an equivalent LTI controller could be achieved. The existing frequency domain analysis methods, its straightforward implementation and the increase in performance achieved in experiments validate the potential of reset control as a suitable alternative to LTI control for industry. Nevertheless, limitations in the explored reset control structures still exist and further work is required in order to achieve the full potential that this technique has to offer.