You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: A Review on Energy-Saving Optimization Methods for Robotic and Automatic Systems 
Chapter Title:  Hardware Addition: Energy Storing and Recovering 
1. Abstract of Cited Paper (BIB001):  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. 
2. Abstract of Cited Paper (BIB002):  For the problems of complex control and harmonic interference when elevator’s regenerative braking energy feed back to the grid, The paper presents an energy saving program. Renewable energy is stored with super capacitors and used locally. The paper analyzes the basic operating principle of the super-capacitor energy storage device and power operation curves in different conditions. The elevator energy consumption experiments are completed in five typical working conditions. Experimental results show that super capacitor energy storage device of the elevator is stable and has a good energy saving effect. 
3. Abstract of Cited Paper (BIB003):  This paper presents the experimental and simulation results of industrial robot's recuperated energy saving approaches. Two complementary alternatives- a capacitive energy buffer on the robot's DC-bus is evaluated and a novel approach, the robot EnergyTeam has been proposed. The principle of robot EnergyTeam is the DC-bus merging among various number of industrial robot power controllers thus enabling a controlled energy flow among the robots that decelerate and, therefore, recuperate the energy and those that simultaneously require a peak power supply for the acceleration. Cost efficiency is estimated considering the characteristics in robotics of real production in the automobile industry. 
4. Abstract of Cited Paper (BIB004):  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. 
5. Abstract of Cited Paper (BIB005):  This paper proposes a new type of power converter for drive systems to enable the exchange of recuperated energy within an independent DC subgrid having one centralized energy storage element. Many industrial applications that require rapid cyclic starts and stops are subject to significant energy waste at the brake chopper of the DC bus due to over voltage during motor deceleration. The proposed solution allows the brake chopper to be eliminated and the otherwise wasted energy to be stored externally. The solution does not require identical hardware or exact synchronization between the drive rectifiers. Experimental results in industrial robotics show savings of up to 20%. 
6. Abstract of Cited Paper (BIB006):  It is state of the art for many drive systems like those used in industrial robotics, conveyor systems or diverse numerical control machinery to have a common DC bus power system architecture. Due to regenerative braking, the DC bus voltage increases until a certain limit, which is limited means of a balancing resistor (brake chopper). Systems that require rapid cyclic starts and stops are subject to significant energy waste due to extensive use of the brake chopper. In this article, a novel power converter for drive systems is proposed that allows the brake chopper to be omitted and enables the exchange of regenerative energy among multiple drive systems within an independent DC subgrid with one centralized energy storage element. The solution does not require identical hardware or exact synchronization between the drive rectifiers, therefore it is applicable to both existing and new production equipment alike. Experimental results in industrial robot drives show savings of up to 20%. 
7. Abstract of Cited Paper (BIB007):  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. 
8. Abstract of Cited Paper (BIB008):  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. 
9. Abstract of Cited Paper (BIB009):  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.

Literature Review:
One of the most recent techniques adopted to reduce the energy expenditure of mechatronic and robotic systems is the addition of energy-storing and -recovering devices. The main idea behind these devices is to harvest the energy during the braking phase-which is usually wasted-store it, and provide it back to the system when necessary BIB009 BIB001 BIB005 BIB008 BIB002 BIB010  BIB003  BIB004 BIB006 BIB007  . Two different types are considered and analyzed: (1) the type of energy-storing devices used, and (2) energy-sharing via the interaction between actuators exchanging energy in a multi-actuator system.