Evaluating the Mechanical Redesign of a Biped Walking Robot Using Experimental Modal Analysis

Assessment of Parallel Robot Dynamic Characteristics Using Experimental Modal Analysis and Finite Elements

“…Figure (5) present a sample of the EMA FRF and coherence curves for all models with two measurement locations for one model, the coherence curve indicates the status of the measurement and select the range of perfect frequencies in FRF, in general, the coherence curve indicating that the maximum frequency could be obtained with no error in measurements is located in the range of frequencies between (4650-5500 Hz). Figure (6) shows the obtained FRF curves for all models using Ansys software, figure (7) presents a sample of the mode shapes at all frequencies for all models and the value of deformation for one model, all data for all models was sorted in the table (2)(3)(4). Ahmed Deabs, Fawkia Gomaa, Khaled Khader "Assessment of Parallel Robot Dynamic …….."…”

“…Elosegui [2] described the nonlinear characteristic of the Puma 560 robot by using EMA, two models were proposed and measured to get the system response, the results were compared to identify the nonlinearities and select suitable measurement techniques. The dynamic structural evaluation of the redesigned LOLA walking robot was obtained by performing EMA on the structure at more than one point, the results were also compared with open-loop transfer functions results [3], Wu and Kuhlenkoetter [4] obtained the dynamic stiffness of IRB 4400 industrial robot by using experimental modal analysis, the results from measurements were converted by two mathematical approaches to get the dynamic stiffness, the comparison showed the significant difference between them and declared the best method. Modal parameters (natural frequencies, modal damping ratios, and mode shapes) of ABB IRB 6660 robot were identified using EMA, the results were discussed to improve the robot structure, reduce the vibration and increase the accuracy [5].…”

Anthropomorphic walking robot: Design and simulation

“…Unlike the technical solutions of walking robots discussed above [2,3,6,13], which have a separate drive for each leg joint, the proposed anthropomorphic walking mechanism contains a minimum of drives for each leg. In relation to other structures considered in Section 2, the proposed walking mechanism has a significantly lower cost due to the minimization of drives and the use of sealed gas chambers for energy recovery.…”

“…This design is interesting from the point of view of minimizing the number of drives. An estimate of the mechanical model of a bipedal walking robot is also presented in [6]. Studies [7,8] are of interest from the point of view of optimal control of anthropomorphic structures.…”

“…We substitute the found expressions of the derivatives mentioned above and generalized forces into equation (6), and after simplifying the intermediate expressions, we obtain a system of differential equations of robot motion (14):…”