LAUNCHING  PLATFORMS FOR AAD PROGRAMME

 A mobile multi-role launching platform based on state-of-the-art all electric servodrive technology incorporating low voltage, high performance DC servomotors and PWM drive has been developed for AAD missile. The launcher has been configured on TATRA VVL 8 x 8 platform and is capable of multi-axes positioning of heavy payload of missile in various modes like inclined and vertical launch with high level of pointing accuracy. The launcher has ‘stop-slew-launch’ and ‘launch-while-track’ capability. The launcher is also capable of launching canisterised as well as non-canisterised missiles. It can operate in an automatic manner from a local as well as a remote Launch Control Centre (LCC) situated 500 m away and can faithfully execute the positioning and tracking commands generated by the LCC. A closed loop servo drive system employing all electric servodrive technology has been used in the launcher to enable fast and accurate positioning of the missiles in multiple axis. The electric drive technology has been selected specially for its advantages of compact size, high power-to-weight and torque-to-inertia ratio resulting in fast response and quick reversibility. It also offers other advantages of high reliability, clean and silent operation as well as reduced maintenance and modular construction.     

                                                                                                              

 
              
Mobile launcher for AAD

The servodrive has been designed using state-of-the-art highly efficient linear electromechanical actuators (LMA), low voltage DC servomotors, and PWM drive. The low voltage DC motors operate on 28 V DC supply and enable operation of the launcher even on 28 V batteries other than normal diesel generator set-based power source. This enables silent and uninterrupted operation of launcher if need be. The LMA employing ball screws have been designed with a specific view of achieving high positional accuracy due to minimum backlash and high rigidity at the same time providing high transmission efficiency (> 90 per cent).

 

The elevation drive system of launcher has been designed using twin DC motors driving a common payload through a ball screw. The twin motors have been synchronised mechanically through a special custom-built gear box to offer a highly efficient, compact and jam proof drive system. The gear box is planetary type and has been designed to provide high efficiency, minimum backlash and high stiffness and at the same time offering large speed reduction (torque amplification) in a very compact size and minimum weight.        

                                                                                                 

The launcher platform structure and mechanisms have been configured and designed using latest CAD and CAE tools such as IDEAS, Solid Works, etc. It has been further optimised for weight and stiffness using ANSYS FEA package. The structure has been configured as a 3-D space structure and fabricated out of SA 516 Gr 70, specifically been selected for low temperature impact proportion.

 

An automatic platform levelling system employing electromechanical outriggers has been provided on the launcher. It consist of DC servomotors and power screws operating in a closed loop manner under the commands of a dedicated microporcessor-based controller. The usage of electromechanical actuators enables high reliability, minimum maintenance, and manual operation in addition to automatic. An innovative and novel concept of using torsion bars as a mechanism for energy storage had led to substantial reduction in the drive power requirement of the launcher resulting into usage of a lower capacity actuator and power source system. It is capable of being deployed on any cross-country condition and can be automatically levelled using electromechanical outriggers.

 

The AAD launcher is capable of operating in universal power supply scheme and has been installed with a diesel PTO driven generator set. The launcher controller is designed based on state-of-the-art technology incorporating hardware independent configuration and digital controls based on realtime operating system (RTOS), VME architecture, power PC processor and CPLDs. DRDO has also successfully developed mobile tracked vehicle-based launchers for Akash and Trishul missiles. The operation of these launchers is fully automatic and is remotely controlled by a `Battery Control Centre’, situated 500 m away. Control is affected via radio or line links. The launchers are microprocessor driven and controlled through an electromechanical servodrive system. They have their own inbuilt gas turbine driven generators. These systems have undergone all the technical trials successfully including track trials, electromagnetic interference/electromagnetic compatibility trials, and flight trials.

 

Technical Specifications

 

Parameter

Elevation

Azimuth

                    System payload                                          3500 kg                                                        7200 kg

                          System inertia                                            25000 kgm 2                                                 18000 kgm2

                   Launch angle

                                 Inclined launch                                      200 to 700                                                  +1800 to -1800

                                Vertical launch                                       700                                                                  –

                       Freedom of rotation                                       00 to 930                                                      3600

                 Slewing                                                       200 to 700 in 8 s                                            1800 in 9 s

                      Tracking                                                       0.10 C/s to 100 C/s                                       0.10 C/s to 100 C/s

                      Resolution                                                    0.10                                                              0.10

                 Positional accuracy

                                    Static                                               0.50                                                                                    0.50

                           Dynamic                                          0.50                                                                0.50

 

 

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