A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Energy-Storing-Devices Type <s> Powering a robot is one of the biggest challenges in robot design, which is one of new technologies that will positively impact robotics. Flywheel is a kind of device for energy conversion and storage, which is known as electro-mechanical battery. In this paper, a kinetic energy recovery system (KERS) for rubber-tyred gantry (RTG) crane robot is explored, which is based on a surface-mounted permanent magnet synchronous motor (PMSM) with an integrated flywheel spinning at high speed. At first, the basic background of situation RTG crane robot is introduced, afterwards the KERS is discussed to show that it can be perfectly used to meet the peak energy requirements of crane during both acceleration and regenerative braking. Then, a typical structure of KERS is designed step by step. A saturated inductance is designed to reduce the total harmonic distortion (THD) and allow the withdrawal of a large amount of currents. Direct paralleling of two insulated gate bipolar transistor (IGBT) modules is developed with consideration of the power demand. Next, the operation of the integrated system including power electronics, sensors and digital signal processor (DSP) is explained. The algorithm regulates the operation of the pulse width modulation (PWM) converter is realized by proportional plus integral (PI) controllers for charging the flywheel with constant current and discharging under constant power. Finally, the feasibility of the proposed system is verified by simulation. <s> BIB001 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Energy-Storing-Devices Type <s> Pneumatic actuators are widely used in industry and many other applications, whereas low energy efficiency has been recognized as a critical drawback compared with corresponding hydraulic and electrical actuators. The paper presents a new hybrid pneumatic-electrical system aiming at energy efficiency improvement by recovering exhaust air energy from pneumatic actuator outlets to generate electricity. A closed-loop control strategy is proved to be essential to ensure the exhaust energy recovery work properly and to maintain existed actuator operations simultaneously. The whole system mathematical model and the simulation results are presented in the paper. The laboratory test results are also given. The simulation and experimental study demonstrate that the designed system with the proposed control strategy can operate at the relative higher energy efficiency state for the specified working conditions. <s> BIB002 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Energy-Storing-Devices Type <s> Abstract In this study, a novel hydraulic energy-regenerative system was presented from its proposal through modeling to its control. The system was based on a closed-loop hydrostatic transmission and used a hydraulic accumulator as the energy storage system fabricated in a novel configuration to recover the kinetic energy without any reversion of the fluid flow. The displacement variation in the secondary unit was reduced, increasing the uses of several types of hydraulic pump/motors. The proposed system was modeled based on its physical attributes. A hierarchal control system was implemented and focused on the design of an adaptive fuzzy sliding mode control for speed control of the secondary unit. The energy utilization and the influences on the energy-recovery potential of the system were analyzed. Simulation and experiments were performed to evaluate the validity of the employed mathematical model and the effectiveness of the control system. The experimental results indicated that the designed system was effective and that the round trip recovery efficiency varied from 22% to 59% for the test bench. <s> BIB003 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Energy-Storing-Devices Type <s> Mobile hydraulic systems are developed toward better control performance and higher energy efficiency. Pressure compensators, which govern the pressure drops over the control orifices, are widely used in multiactuator systems to improve their operability. However, additional energy is also dissipated in the compensators especially under the overrunning load conditions. This paper presents a novel energy-saving system, where the compensator is designed as a regeneration device consisting of a hydraulic motor and an electric generator. Then, hydraulic energy can be regenerated and pressure compensation function is realized by adapting the electromagnetic torque of the generator to the load as well. The close-loop control of the generator is designed by effective pressure drop estimation. The proposed energy-saving system and controller are implemented on an experimental platform of hybrid excavators which is equipped with an electric energy storage device. The experimental results show both good control performance and significant energy-saving effect. <s> BIB004 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Energy-Storing-Devices Type <s> This paper investigates feasibility of using a flywheel based energy recovery and storage system for a robotic manipulator. The incentive is supported by ever growing necessity for efficient systems and optimisation of power consumption of industrial processes. Previous work has shown that robotic manipulators can benefit from incorporation of energy recovery and temporary energy storage system which resulted in significant reduction in power consumption. The ABB IRB 140 manipulator is used as a test bed for simulation and data collection. The manipulator internal parameters are identified and model is constructed using MATLAB/Simulink. The manipulator is programmed to executed a number of trajectories representing typical industrial tasks during which joints data is recorded and applied to the model. Simulation results show that flywheel based energy storage system is fully compatible with the manipulator controller hardware and is able to achieve reduction in power consumption. <s> BIB005 </s> A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems <s> Energy-Storing-Devices Type <s> Power-efficient fluidic driven system is beneficial to extending the working time of autonomous and wearable soft robots supplied by independent power sources such as batteries. In this paper, an energy recovery scheme is proposed to reutilize the pressurized air released by retracting pneumatic soft actuators instead of venting to atmosphere. The scheme's novelty lies in an air accumulator employed to store the recovered energy and boost the inlet pressure of air pumps when there is requirement. Then the energy-saving principle is described based on the comparison of energy flow between the systems with and without energy recovery. Residual pressure, recoverable energy and parametric effect are also presented analytically according to the ideal gas law. Finally, simulation models are developed to evaluate the system performance and the results show that about 20% reduction of power consumption and acceptable residual pressure can be achieved simultaneously when the accumulator volume is three times of the actuator volume, which provides reference to further prototype development. <s> BIB006
The energy-storing-devices type includes the components that allow the recovering and storing of energy to use when needed. According to  , these kinetic-energy recovery systems (KERS) can be subdivided into the following: 1. Mechanical KERS (e.g., flywheels). 2. Electric KERS (e.g., chemical batteries, capacitors, and supercapacitors). 3. Hydraulic KERS (e.g., hydro-pneumatic accumulator). 4. Hydro-electric KERS (e.g., a hydraulic motor coupled with an electric generator). In  , a comparison between the different types of energy-recovery systems is made, considering aspects such as voltage instability, working temperature range, efficiency and cost. According to the authors, the flywheel results as the best KERS system in terms of voltage stability, temperature range and efficiency. In BIB005 BIB001 , a flywheel is added to a mechatronic system in order to store energy: in this case, the flywheel is considered as an additional axis of the system. Gale et al. BIB005 simulated an anthropomorphic manipulator programmed to execute a number of typical movements generally used in manufacturing. The results show that a flywheel-based energy-storage system is fully compatible with the manipulator controller hardware, and it is able to achieve a reduction in power consumption. Xu et al. BIB001 analyzed the case of a three-degrees-of-freedom, rubber-tyred gantry crane robot provided with a surface-mounted permanent magnet synchronous motor (PMSM) and an integrated flywheel spinning at high speed. They demonstrated that the method can be used to perfectly meet the peak energy requirements of the crane during both acceleration and regenerative braking. Pneumatic driven systems (e.g., grippers and actuators) are widely used in mechatronic systems given their simplicity and reliability. However, their efficiency is lower with respect to corresponding hydraulic and electrical technologies BIB002 BIB006 . Thus, interesting results could be expected by applying an energy-reducing method. In BIB002 , a hybrid pneumatic-electrical system that recovers exhaust air energy from pneumatic actuator outlets to generate electricity through a scroll-type air motor is proposed. In BIB006 , an energy recovery scheme is studied that reuses the pressurized air released by retracting pneumatic soft actuators instead of venting to the atmosphere. Simulation results show that a suitable air accumulator allows savings of about 20% of the energy consumption with an acceptable residual pressure BIB006 . Hydraulically actuated systems have also been used. In BIB003 , a closed-loop hydrostatic transmission equipped with a hydraulic energy-regenerative system is presented. The hydraulic accumulator is used as the energy-storage system without a reversal of the fluid flow. In BIB004 , the authors substitute the hydraulic compensator, a device that allows governing the pressure drops over the control orifices in a plant, with a regenerative device: a hydraulic motor coupled with an electric generator and an electrical capacitor to store recovered energy. In this case, the pressure compensation is realized by adapting the electromagnetic torque of the generator to the load.