OPTIMAL CONTROL OF SWAY IN HYDRAULIC BOOM CRANES OF RECOVERY VEHICLES

Abstract

Due to inertia, undesirable sway in the payload is observed during a recovery operation; in which a vehicle or equipment casualty is evacuated with the help of a recovery vehicle for its further extrication to a repair site. This recovery operation is usually carried out by military or commercial recovery resources with the assistance of a rotary crane vehicle 765 evacuate men and material from debris after a catastrophe like earthquake, accidents etc. Generally, the payload oscillations are manually controlled by detailing few personnel of the recovery crew to hold the payload which violates safety of recovery crane operation. Manual control of the payload oscillations also results in the commitment of skilled recovery crew thus retarding speed and efficiency of the process. Therefore, in this research work, a robust controller has been designed for intelligent control of these payload oscillations in a mobile recovery crane. An EFI based Light Recovery Vehicle (LRV); IVECO Euro-Cargo has been selected for designing a robust controller to regulate its payload oscillations. The Rotary boom crane and its luffing motion were duly modeled while catering for the effects of varying environmental parameters like wind speed, disturbances etc. Various control schemes based on even intelligent and adaptive controllers have now been matured enough for overhead, fixed and tower types of cranes due to their wider applications on industrial scale. However, for mobile recovery vehicles operating in an open / unstructured field environment, a little research has been done to find a suitable anti-sway control scheme. Therefore, as an initial step, anti-sway control scheme based on classical PID controller has been suggested with the feedback available from newly installed sensors on the boom crane mechanism in addition to the already installed sensors in the EFI vehicle. The simulations results have been compared with an optimal LQR controller which showed an improvement in the settling time by 4.5 seconds as compared to the existing crane mechanism where no control scheme is available to control the payload oscillations. Therefore, the application of the suggested control scheme has resulted in reducing the sway present in vehicle / equipment casualty thereby improving the safety, efficiency and speed of the recovery process.