A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> The authors describe the operation of a tendon-driven manipulator, the CT ARM-I, which has a tendon traction force transmission mechanism in which the pair of tendons that drive a joint are pulled from base actuators via pulleys mounted on the base-side joints. The mechanism makes the most of the coupled drive function of the tendon traction forces and thus enables the lightweight manipulator to exhibit enormous payload capability. The manipulator has a solid structure and is inexpensive to manufacture because of its mechanical simplicity. Experiments demonstrate that the CT ARM-I has an active compliance arm and offers payload capability superior to that of conventional manipulators. > <s> BIB001 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> A third generation of torque-controlled light weight robots has been developed in DLR's robotics and mechatronics lab which is based on all the experiences that have been had with the first two generations. It aims at reaching the limits of what seems achievable with present day technologies not only with respect to light-weight, but also with respect to minimal power consumption and losses. One of the main gaps we tried to close in version III was the development of a new, robot-dedicated high energy motor designed with the best available techniques of concurrent engineering, and the renewed efforts to save weight in the links by using ultralight carbon fibres. <s> BIB002 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> A method for the selection of motor and gearhead in mechatronic applications is proposed. The method is applicable to any kind of load and helps to find the optimal motor gearhead combination with respect to output torque, peak power, mass/size and/or cost. The input to the method is the load cycle and component data on candidate motors and gearheads. Output is a set of graphs of all motor/gear ratio combinations that can drive the given load. From these graphs it is easy to read out the peak power, motor torque and energy efficiency for all feasible motor/gear ratio combinations. <s> BIB003 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> Purpose – The paper seeks to present a new generation of torque‐controlled light‐weight robots (LWR) developed at the Institute of Robotics and Mechatronics of the German Aerospace Center.Design/methodology/approach – An integrated mechatronic design approach for LWR is presented. Owing to the partially unknown properties of the environment, robustness of planning and control with respect to environmental variations is crucial. Robustness is achieved in this context through sensor redundancy and passivity‐based control. In the DLR root concept, joint torque sensing plays a central role.Findings – In order to act in unstructured environments and interact with humans, the robots have design features and control/software functionalities which distinguish them from classical robots, such as: load‐to‐weight ratio of 1:1, torque sensing in the joints, active vibration damping, sensitive collision detection, compliant control on joint and Cartesian level.Practical implications – The DLR robots are excellent rese... <s> BIB004 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> In order to minimize the energy dissipated in a mechanical servo system, the present paper proposes a design method for a reduction ratio in a gear train with frictions of all types. The Coulomb friction in the servo system is represented by the efficiency of the gear train. Even if the system is nonlinear due to the Coulomb friction, an optimal velocity function can be obtained analytically by introducing a zero crossing time. This is the time at which the input torque of the gear changes from the positive direction to the negative one. This velocity function depends on the system parameters and thus the moment of inertia and the viscous friction of the gear train are expressed in terms of the reduction gear ratio. The energy dissipated due to the optimal velocity function is partially differentiated with respect to the zero crossing time and the gear ratio. The resulting optimal gear ratio is compared to that obtained from the conventional inertia matching method. The results of simulations indicate that the optimal gear ratio can greatly reduce the amount of the dissipated energy. <s> BIB005 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> It is important to minimize the energy dissipated by the reduction gears and motors in a three-jointed vertically articulated manipulator. This paper proposes an optimal design method for simultaneously determining eight design variables, which are three motor masses, three reduction gear ratios, a counterbalancer mass for the third link and an offset between the first and the second links. Using these design variables, the equation of motion and the dissipated energy can be expressed as functions of the moment of inertia and the Coulomb friction torque of the joints and the inertia matrix of the manipulator. Optimal design variables can be determined by minimizing the dissipated energy under the constraint conditions for the motors and the offset. The numbers of stages for the reduction gear trains are determined from the optimal gear ratios. Simulations show that the proposed design method can reduce the dissipated energy more effectively than the inertia matching method. <s> BIB006 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> In order to improve the performance and energy efficiency of the pneumatic drive, the by-pass valve control scheme is designed and studied. For pneumatic positioning application, in the constant speed phase, the inlet and outlet chambers will be connected via by-pass valve to reduce the overshoot and allow some exhaust compressed air to be reused. Therefore, compared with the traditional control of the motion of the asymmetric cylinder, a 12–28% saving in energy use can be acquired and meanwhile the position accuracy is maintained. Preliminary results from the simulation and experiment studies will be reported. <s> BIB007 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> The industrial sector is the largest users of energy around the world. Industrial motor uses a major fraction of total industrial energy uses. This paper describes a comprehensive literature review about electric motor energy analysis. This paper compiles latest literatures in terms of thesis (MS and PhD), journal articles, conference proceedings, web materials, reports, books, handbooks on electrical motor energy use, losses, efficiency, energy savings strategies. Different types of losses that occur in a motor have been identified and ways to overcome these losses explained. An energy audit that helps to identify motor energy wastages have been discussed extensively. As motors are the major energy users, different energy savings strategies such as use of high-efficient motor, variable speed drive (VSD), and capacitor bank to improve the power factor to reduce their energy uses have reviewed. Different policy measures (i.e. regulatory, voluntary and incentives based) to save motor energy use have been reviewed and presented in this paper. In this review, computer tools that can be used to analyze electric motors energy used has been discussed. Cost parameters to carry out economic analysis have been shown as well. Moreover, payback period for different energy savings strategies have been identified. <s> BIB008 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> Research on joint torque reduction in robot manipulators has received considerable attention in recent years. Minimizing the computational complexity of torque optimization and the ability to calculate the magnitude of the joint torque accurately will result in a safe operation without overloading the joint actuators. This paper presents a mechanical design for a three dimensional planar redundant manipulator with the advantage of the reduction in the number of motors needed to control the joint angle, leading to a decrease in the weight of the manipulator. Many efforts have been focused on decreasing the weight of manipulators, such as using lightweight joints design or setting the actuators at the base of the manipulator and using tendons for the transmission of power to these joints. By using the design of this paper, only three motors are needed to control any n degrees of freedom in a three dimensional planar redundant manipulator instead of n motors. Therefore this design is very effective to decrease the weight of the manipulator as well as the number of motors needed to control the manipulator. In this paper, the torque of all the joints are calculated for the proposed manipulator (with three motors) and the conventional three dimensional planar manipulator (with one motor for each degree of freedom) to show the effectiveness of the proposed manipulator for decreasing the weight of the manipulator and minimizing driving joint torques. <s> BIB009 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Hardware Replacement <s> Minimizing the computational complexity of torque optimization and the ability to calculate the magnitude of the joint torque accurately will result in a safe operation without overloading the joint actuators. Reduced torque will lead to lighter robotic arm and easier control. The main objective of this work is to design a robotic arm with all the motors located at the base so that the arm becomes lighter than the conventional arms. The main advantage from this development is to decrease the torque required to control the arm. The motion of motors is transferred to links via aluminum pulleys, bearings, and timing belts which yields to the need of lighter motors and hence a lighter manipulator. The maximum torque of each joint has been calculated then compared with the torque needed using conventional design to show the effectiveness of the proposed design for decreasing the weight of the manipulator and minimizing driving joint torques. <s> BIB010
The second of the considered strategies is the lighter design of components to reduce the moving masses; this means reducing the weight and inertia of arms. In this manner, the driving torque can be reduced, in turn using less energy and leading to an easier control BIB004 BIB010  BIB002  BIB001 BIB009  . In BIB002 , arms made of an ultralight carbon-fibre-reinforced polymer are studied, while in  , an optimal design of a serial-link robotic manipulator is evaluated. In the latter, the aim is to find the arms' optimum diameter as well as the optimum dimensions of lightening holes in order to minimize the masses without detrimentally affecting the structural-mechanical behavior. Lighter components can be installed as in BIB004  , in which special lightweight rotary joints are designed as the result of an optimization process. Following the well-known idea of reducing the moving masses by moving the actuator to the robot base BIB010  BIB001 BIB009 , different solutions have been proposed for serial-link manipulators. In these works, the opportunity of installing the motor near or on the chassis is often achieved by transferring the motion via pulleys and timing belts. In BIB010 , a planar redundant manipulator with three degrees of freedom is presented, in which the motion is transferred through aluminium pulleys, bearings, and timing belts. In  BIB001 , a lightweight tension amplifying mechanism is used: a joint is moved by pushing and pulling two cords connected on it, on diametrically opposed positions. In this way, the weight of the arms is reduced, as the motors are fixed on the chassis. Beyond this, it increases the joint stiffness, which is essential for a precise and rapid manipulation. In BIB009 , a mechanical design of a three-dimensional, planar, redundant manipulator in which only three motors, mounted near the base, are needed to control a system of any number of degrees of freedom is presented. In more detail, the third motor actuates all except the first two joints as a result of the connection through shafts and gears between links. Focusing the attention on the driving system, for example, the motor and transmission, different options can be implemented to increase energy efficiency. Saidur BIB008 presents a detailed analysis on electric-motor energy losses and on strategies to increase the efficiency. These are mostly based on the design of a more efficient motor (e.g., increasing the cross-section of the coil, and the design of a low-loss magnetic core). In BIB005 BIB006 BIB003 , the optimal efficiency design of a gear train, in terms of the optimal gear ratio taking into account the Coulomb and viscous friction, is presented. In BIB007 , an application for a pneumatic asymmetric cylinder actuator is presented. In this application, it is possible to save energy by connecting the two chambers through a bypass valve during the constant-speed phase. Under this condition, an air pressure difference exists between the two chambers, as forces are equilibrated and the presence of the rod reduces one of the piston areas.