In this paper, an algorithm is proposed to improve the MAXIMUM LOAD CARRYING CAPACITY (MLCC) of flexible robot manipulators. The MAXIMUM allowable LOAD which can be achieved by a flexible manipulator along a given trajectory is limited by the joints' actuator CAPACITY and the end effector accuracy constraint. In an open-loop approach, the end effectors deviation from the predeffned path is significant and the accuracy constraint restrains the MAXIMUM payLOAD before actuators go into saturation mode. By using a controller, the accuracy of tracking will improve. The actuator constraint is not a major concern and, therefore, the full power of the actuators, which leads to an increase in the MAXIMUM LOAD CARRYING CAPACITY, can be used. In this case, the controller can play an important role in improving the MAXIMUM payLOAD, so a robust controller is designed. However, the control strategy requires measurement of the elastic variables' velocity, which is not conveniently measurable. So, a nonlinear observer is designed to estimate these variables. A stability analysis of the proposed controller and state observer is performed on the basis of the Lyapunov Direct Method. In order to verify the effectiveness of the presented method, simulation is done for a two link flexible manipulator. The obtained MAXIMUM payLOAD for open and closed-loop cases is compared, and the superiority of the method is illustrated.

In this paper, a computational method for obtaining the MAXIMUM Dynamic LOAD CARRYING CAPACITY (DLCC) for the 6-UPS Stewart platform manipulator is developed. In this paper, the manipulator is assumed to be non-rigid and the joint actuator torque CAPACITY and accuracy of motion are considered major limiting factors in determining the MAXIMUM payLOAD. The MAXIMUM dynamic payLOAD CARRYING CAPACITY of the manipulator is established, while the dynamic model of a typical hydraulic actuator system is used in the joint actuator force CAPACITY for a given trajectory. The flexibility of the manipulator is assumed to be eventuated from the manipulator's joints flexibility. According to the high complexity of the dynamic equations system of the flexible joints parallel manipulators, the effects of the flexibility of the prismatic joints are considered in a static situation to show the considerable effects of the joint's flexibility on the motion accuracy of the 6UPS-Stewart platform. This method can be used for determining the MAXIMUM dynamic payLOAD, which acts as an end-effector for the mechanical design of the manipulator and the optimized selection of the actuator, such as machine tools, based on the hexapod mechanism.

In this paper, optimal trajectory planning of flexible joint manipulator in point-to-point motion is presented in which besides the determining the MAXIMUM LOAD CARRYING CAPACITY, the vibration amplitude is also reduced. The solution method is on the base of the indirect solution of optimal control problem. For this purpose, an appropriate objective function is defined, dynamic equations are derived in state space form, Hamiltonian function is developed and necessary optimality conditions are obtained by using the Pontryagin MAXIMUM principle. In order to reduce the vibration of the end effector during the path, an appropriate state variables are defined and the control law is improved to omit the suddenly variation in applied torque. Then, in order to illustrate the power and efficiency of the proposed method, a number of simulation tests are performed for a two-link manipulator. To this end, after deriving the equation in details, two simulations are performed. In the first case, determining the MAXIMUM LOAD without considering the vibration is solved, in the second simulation, optimal trajectory with MAXIMUM LOAD and minimum vibration is obtained. Finally discussions on the obtained results are presented.

In this paper, according to high LOAD CAPACITY and rather large workspace characteristics of cable driven robots (CDRs), MAXIMUM dynamic LOAD CARRYING CAPACITY (DLCC) between two given end points in the workspace along with optimal trajectory is obtained. In order to find DLCC of CDRs, joint actuator torque and workspace of the robot constraints concerning to non-negative tension in cables are considered. The problem is formulated as a trajectory optimization problem, which is fundamentally a constrained nonlinear optimization problem. Then the iterative linear programming (ILP) method is used to solve the optimization problem. Finally, a numerical example involving a 6 DOF CDR is presented and results are discussed.

Background: Along with rapid economic growth, many natural regions, meadows, farms, etc. have been converted into unbridled urban areas. Urban development converts natural areas into districts full of buildings leading to disrupted ecological balance of the ecosystem. The CARRYING CAPACITY (CC) of urban ecosystems needs to be estimated because they require large amounts of materials and energy as well as the ability of pollutant absorption in a small location. The amount of material and energy used in cities may be more than of that provided by urban CC. High consumption rate is associated with high levels of contamination that transcends the UCC. Therefore, the CC of the urban environment and its population CAPACITY must be evaluated for urban development planning. Materials and Methods: In this study, UCC LOAD number within the pressure-state-impact-response (PSIR) framework and 20 indicators were used to evaluate the CC and pressure on the urban ecosystem of Semnan. Results: According to the results, the LOAD number in the district 1 was equal to 180. 05with a low to moderate pressure on the urban ecosystem. The LOAD numbers in districts 2 and 3 were respectively 230. 41 and 272. 86 imposing a moderate to high pressure on urban ecosystem. Conclusions: Because of the greater population density in the District 3, materials and energy consumption and waste production was higher leading to a higher pressure on the urban ecosystem.

In this paper, a formulation is developed for obtaining the optimal trajectory of robot manipulators to maximize the LOAD CARRYING CAPACITY for a given point-to-point task. The presented method is based on open loop optimal control. The indirect approach is employed to derive optimality conditions based on Pontryagin's Minimum Principle. The obtained necessary conditions for optimality lead to a two-point boundary-value problem solved via a multiple shooting method with the BVP4C command in MATLABâ Since the CARRYING payLOAD is one of the system parameters, a computational algorithm is developed, which provides the capability of calculating the MAXIMUM payLOAD for a point-to-point task. The main advantage of this method is obtaining various optimal trajectories with different MAXIMUM payLOADs and path characteristics by changing the penalty matrices values. To demonstrate the efficiency of the proposed method and algorithm in obtaining the MAXIMUM payLOAD trajectory, simulation is performed on a two-link manipulator.

The calculation of the LOAD CARRYING CAPACITY of variable thickness circular plates subjected to arbitrary rotational symmetric LOADing is presented. The analysis considers plate materials that obey either the square or the Tresca yield criterion. By using upper and lower bound theorems of limit analysis, corresponding estimations for the LOAD CARRYING CAPACITY of the plate are obtained. It is shown that these two bounds are identical. Therefore, the obtained solution would represent the exact amount of the LOAD CARRYING CAPACITY of the variable thickness circular plate. Finally, in order to obtain solutions for some special cases, plates having step changes in thickness and those with linear thickness variation are considered and corresponding results are illustrated.

A computational approach is presented to obtain the optimal path of the end-effector for the 10 DOF bipedal robot to increase its LOAD CARRYING CAPACITY for a given task from point to point. The synthesizing optimal trajectories problem of a robot is formulated as a problem of trajectory optimization. An Iterative Linear Programming method (ILP) is developed for finding a numerical solution for this nonlinear trajectory. This method is used for determining the MAXIMUM dynamic LOAD CARRYING CAPACITY of bipedal robot walking subjected to torque actuators, stability and jerk limits constraints. First, the Lagrangian dynamic equation should be written to be suitable for the LOAD dynamics which together with kinematic equations are substantial for determining the optimal trajectory. After that, a representation of the state space of the dynamic equations is introduced also the linearized dynamic equations are needed to obtain the numerical solution of the trajectory optimization followed by formulation for the optimal trajectory problem with a MAXIMUM LOAD. Finally, the method of ILP and the computational aspect is applied to solve the problem of trajectory synthesis and determine the dynamic LOAD CARRYING CAPACITY (DLCC) to the bipedal robot for each of the linear and circular path. By implementing on an experimental biped robot, the simulation results were validated.