Dynamics and Control of a Robotic Arm Having Four Links

Performance comparison of structured [Formula: see text] based looptune and LQR for a 4-DOF robotic manipulator

We explore looptune, a MATLAB-based structured [Formula: see text] synthesis technique in the context of robotics. Position control of a 4 Degree of Freedom (DOF) serial robotic manipulator developed using Simulink is the problem under consideration. Three full state feedback control systems were developed, analyzed and compared for both steady-state and transient performance using the Linear Quadratic Regulator (LQR) and looptune. Initially, a single gain feedback controller was synthesized using LQR. This system was then modified by augmenting the state feedback controller with Proportional Integral (PI) and Integral regulators, thereby creating a second and third control system respectively. In both the second and third control systems, the LQR synthesized gain and additional gains were further tuned using looptune to achieve improvement in performance. The second and third systems were also compared in terms of tracking a time-dependent trajectory. Finally, the LQR and looptune synthesized controllers were tested for robustness by simultaneously increasing the mass of each manipulator link. In comparison to LQR, the second system consisting of Single Input Single Output (SISO) PI controllers and the state feedback matrix succeeded in meeting the control objectives in terms of performance, optimality, trajectory tracking, and robustness. The third system did not improve performance in contrast to LQR, but still showed robustness under mass variation. In conclusion, our results have shown looptune to have a comparatively better performance over LQR thereby highlighting its promising potential for future emerging control system applications.

A Critical Review of Control Techniques for Flexible and Rigid Link Manipulators

There is a high demand for developing effective controllers to perform fast and accurate operations for either flexible link manipulators (FLMs) or rigid link manipulators (RLMs). Thus, this paper is beneficial for such vast field, and it is also advantageous and indispensable for researchers who are interested in robotics to have sufficient knowledge about various controllers of FLMs and RLMs as the controllers’ concepts are elaborated in detail. The paper concentrates in critically reviewing classical controllers, intelligent controllers, robust controllers, and hybrid controllers for both FLMs and RLMs. The advantages and disadvantages of the aforementioned control methods are summarized in this paper; it also has a detailed comparison for the controllers in terms of the design difficulty, performance, and the suitability for controlling FLMs or RLMs.

Design of a robotic manipulator for handling products of automotive industry

Automation is a process of handling and transport of products, which allows replacing man’s control by operation of manipulators and robots. It represents a highly complex process, which includes several operations and they are usually performed automatically by particular devices. In this article, a technical design of a universal versatile robotic manipulator for handling with automotive products is presented. The designed device is intended for handling with automotive products with a maximum weight of 25 kg. The technical solution of the manipulator comes from required specifications and operation conditions given by the customer, who will install it as a part of an automatic line. A particularity of the manipulator is the special functionality, which allows handling with objects of both circular and angular shapes. This is ensured by adaptable gripping fingers, which are able to adjust their position by means of a well-considered mechanism. The technical design of the manipulator includes calculation of forces needed for reliable gripping of manipulated objects, choice of a working screw and calculation of the load and carrying out of strength analyses of the main loaded part of the manipulator. Based on results, there is recommended an appropriate material for the manufacture of the device to reach its optimal accuracy of positioning of handled objects during a long-term operation.