Lightweight design leads to the unwanted vibration of industrial robot manipulators. Input Shaping (IS) has been proven to be an effective vibration suppression method. However, applying IS to suppress the vibration of industrial robots faces a challenging problem: time-varying dynamics. To address the time-varying dynamics of robot manipulators, this paper presents a novel and practical solution to vibration suppression based on Time-Varying Input Shaping Technology (TVIST). Our focus in this paper is to develop a practical implementation strategy that can be applied in discrete time. A Fractional Delay Finite Impulse Response filter is employed to design and implement TVIST. This solution makes TVIST more useful in practice because it can be combined with online and discrete-time trajectory generation. It can also be implemented in combination with position control using feed-forward velocity and torque. The performance of the new approach is validated through experimental implementation on a lightweight robot from Universal Robots A/S. Experimental results are analyzed to demonstrate significant vibration suppression and increased productivity of the robot with the proposed solution. The proposed method can be extended to the vibration suppression of other types of industrial robotic manipulators with serial links as well as other time-varying dynamic systems.

This paper presents a new method to generate vibration free rest-to-rest (RTR) trajectories for configuration dependent dynamic systems, such as robots, cranes or machine tools. The new method named 3-Segmented Input Shaping is based on a combination of the widely known Input Shaping method and a new trajectory segmentation strategy for piece wise shaping of the trajectory. The new segmentation strategy facilitates the capability of accounting for variations in system dynamics during motion by shaping acceleration and deceleration profiles with individual frequencies. In this paper the new segmentation strategy is used in combination with the bang-coast-bang (BCB) trajectory. The generated trajectories are described in closed form, hence requires no optimization and thereby provides strong computational performance. The new method is verified by numerical simulations and detailed analysis and shows great potential in vibration-free RTR trajectory generation for systems with configuration dependent dynamics.