In this paper, dynamic and vibration characteristics of a newly developed 5-degrees-of-freedom (5-DOF) long-reach robotic arm for farm applications is studied through finite element analysis (FEA), as well as experimentally. The new manipulator is designed to be light and compact enough that it can be mounted on a small vehicle for farm applications. A finite element model of this novel manipulator was established using a commercial FEA software. FEA was carried out for two different configurations of the manipulator (fully-extended and vertical half-extended). The fully-extended configuration provides the longest reach of the arm and is one of the most commonly used poses in farm applications; vibrations of this configuration are highly affected by its base excitation. The FEA results indicated that the first six natural frequencies of the manipulator for the two configurations considered were between 4.4 to 41.6 (Hz). Modal analysis on the fully-extended configuration was completed using experimental modal analysis to verify the finite element results. In the experiments, acceleration data were obtained utilizing sensors, and were post-processed using Fast-Fourier Transforms. The first six natural frequencies and their corresponding mode shapes were obtained using FEA and also experimentally, and the results were compared; the comparison showed good agreement, with less than 10% difference. Our verified FE model provides a reliable basis for future vibration control for the newly developed robotic arm for different applications. A harmonic response simulation was also carried out using an experimentally corrected FE model; this provides a good understanding of the dynamic behavior of the newly developed arm under base excitation. This paper offers an experimentally corrected FEA model for a large manipulator with base excitation for farm applications.

Dynamic modelling and motion control of a newly developed 5-DOF robot manipulator is presented here. Optimized PID gains are obtained using PSO (Particle Swarm Optimization) method. a PID and a PID-CTC (Computed Torque Control) controller with optimized gains are examined for reference trajectory tracking control for the manipulator. Controllers’ performance for unit step inputs are evaluated using computer simulations. It is shown that this PSO optimized gain PID-CTC controller makes the manipulator follow its trajectory with no steady-state error. Controllers lead to small tracking errors, which is suitable for intended application; the PID-CTC controller provides better overall transient responses. The simulation model presented here, can be used for other applications. Contributions of this paper is mostly on application of PSO for the large 5-DOF manipulator with uncertain settings.