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Conventional hydraulic dampers reduce vehicle vibration by converting the vibration energy into heat. In addition to wasting energy, the fixed damping characteristics of these dampers cannot adapt to different road conditions. As we know, a suspension with tunable damping provides a more comfortable ride. However, previous works regarding tunable regenerative dampers, which usually consist of a single generator, have some shortcomings, including wasted energy and a limited range of tunable damping. With these problems in mind, a new design principle with multiple controlled transducers is discussed in this article. By controlling the number of switched on transducers and adjusting the value of the external resistance, the damping characteristics can be fine-tuned according to the requirements. With this new design principle, a regenerative damper cannot only tune the damping behavior over a broader range but also harvest as much vibration energy as possible. The design principle was verified by building and testing two different prototypes. The experimental results showed that these two dampers could achieve nearly linear turning of the damping coefficient and harvest more electrical power from vibrations than other type of energy-harvesting dampers. [ABSTRACT FROM AUTHOR]

Hydraulic dampers are used to decrease the vibration of a vehicle, where vibration energy is dissipated as heat. In addition to resulting in energy waste, the damping coefficient in hydraulic dampers cannot be changed during operation. In this paper, an energy-harvesting vehicle damper was proposed to replace traditional hydraulic dampers. The goal is not only to recover kinetic energy from suspension vibration but also to change the damping coefficient during operation according to road conditions. The energy-harvesting damper consists of multiple generators that are independently controlled by switches. One of these generators connects to a tunable resistor for fine tuning the damping coefficient, while the other generators are connected to a control and rectifying circuit, each of which both regenerates electricity and provides a constant damping coefficient. A mathematical model was built to investigate the performance of the energy-harvesting damper. By controlling the number of switched-on generators and adjusting the value of the external tunable resistor, the damping can be fine tuned according to the requirement. In addition to the capability of damping tuning, the multiple controlled generators can output a significant amount of electricity. A prototype was built to test the energy-harvesting damper design. Experiments on an MTS testing system were conducted, with results that validated the theoretical analysis. Experiments show that changing the number of switched-on generators can obviously tune the damping coefficient of the damper and simultaneously produce considerable electricity. [ABSTRACT FROM AUTHOR]

An active or semiactive dampers can change its damping property to maintain the tradeoff between ride quality and road handling; however, semiactive dampers need external power supply and active dampers even require considerable power consumption. A regenerative damper has the ability of tuning the damping without the requirement of an external power supply. The aim of this study is to investigate a novel method to conveniently adjust the on-demand damping according to road condition by regenerating vehicle vibration to electricity. In this paper, we propose an electromagnetic energy-harvesting damper with 12 independently-controlled slot winding transducers (SWTs) to investigate the active control method of damping and energy reclaiming from a regenerative damper. By switching on an appropriate number of SWTs and tuning their external resistance to an optimal value, the energy-harvesting damper can both provide on-demand damping and reclaim as much electrical power as possible. Experiments on an MTS testing system showed that both changing the number of switch-on SWTs and tuning their external resistors can adjust the damping coefficient of the energy-harvesting damper, and, hence, the damping tuning can be extended to a large range. The output electrical power was measured on different shunted external resistors, demonstrating that the maximum reclaim of electrical power can be achieved when the shunted resistor is equal to the internal resistance of the SWT. By appropriately arranging the number of switch-on SWTs and their shunted resistors, the electromagnetic energy-harvesting damper can produce on-demand damping, which tuning method is convenient and almost linear. Moreover, thanks to the multiple independently controlled transducers, the proposed energy-harvesting damper can regenerated as much electrical power as possible from the vehicle vibration. [ABSTRACT FROM PUBLISHER]

In recent years, there has been increasing demand for portable power sources because of the rapid development of portable and wearable electronic devices. This paper describes the development of a backpack-based energy harvester to harness the biomechanical energy of the human body during walking. The energy harvester was embedded into a backpack and used a spring-mass-damping system to transfer the energetic motion of the human body into rotary generators to produce electricity. In the oscillation system, the weight of the harvester itself and the load contained in the backpack serve together as the seismic mass; when excited by human trunk motion, the seismic mass drives a gear train to accelerate the harvested energetic motion, which is then delivered to a generator. A prototype device was built to investigate its performance, which has a maximum diameter of 50 mm, a minimum diameter of 28 mm, a length of 250 mm, and a weight of 380 g. Experiments showed that the proposed backpack-based harvester, when operating with a 5 kg load, could produce approximately 7 W of electrical power at a walking velocity of 5.5 km/h. The normalized power density of the harvester is 0.145 kg/cm 3 , which is 7.6 times as much as that of Rome’s backpack harvester [26] . Based on the results of metabolic cost experiments, the average conversion efficiency from human metabolic power to electrical power is approximately 36%. [ABSTRACT FROM AUTHOR]