An experimental study was conducted to compare the performance of an in-house built novel double semi-active damper against a conventional semi-active single damper. Different performance metrics were analyzed, and the performance of the two dampers was evaluated based on these metrics. A Hybrid Skyhook–Groundhook control algorithm was developed and implemented on the variable orifice double damper. The semi-active single damper is governed via two separate control strategies, namely—Skyhook and Groundhook control, respectively. The effectiveness of each algorithm is better understood by adding a normal load on top of the Shock Dyno, thus modifying it to act as a quarter car test rig. The sprung and unsprung acceleration data are collected via the accelerometers mounted on the Shock Dyno through a Data Acquisition System. The results obtained from this experiment provide a strong basis that the semi-active double damper performs better in terms of the comfort cost than that of the commercial semi-active single dampers.
8 May 2023 in SAE International Journal of Advances and Current Practices in Mobility
Suspension systems are an integral part of land vehicles and contribute significantly to the vehicle performance in terms of its ride comfort and road holding characteristics. In the case of Space Exploration Vehicles (SEVs), the requirement of these unmanned vehicles is to rove, collect pictures and transmit data back to the earth. This is generally performed with the help of exteroceptive, and proprioceptive sensors mounted on the main chassis of the SEV. The design of various components of such vehicles is dictated by the assumption of extreme terrain and environmental conditions that it might face. The Mars Exploration Rovers (MERs) have incorporated the use of the “Rocker-Bogie” mechanism for the suspension system which provides relative stability to the MER for various maneuvers. In this work, the “Rocker-Bogie” mechanism is modeled and simulated as a planar kinematic model using parameters of the Perseverance rover. It is found that the Rocker-Bogie tends to nullify the effects of uneven terrain by maintaining the chassis at a relatively fixed location with respect to the ground reference frame. Further, an attempt is made to replace the mechanism with a passive and semi-active suspension module at four corner wheels to study the effects that the semi-active suspension would have on the chassis dynamics of the MER. Lastly, a comparative analysis of the vertical acceleration of the chassis using different suspensions was performed. This concluded that the rocker-bogie mechanism does help to stabilize the chassis dynamic behavior to a greater extent. Future work could include an attempt to utilize the rocker-bogie chassis dynamics as the ideal condition to develop control strategies that can improve the chassis dynamics if individual semi-active suspension systems were employed.