How to Create Instances Statically in Custom RTSC Packages

Ragesh,
there are two functionalities that you can use to access statically generated instances in your C code.
First, you can use Program.global to attach static instances to it as described in the example in the linked documenation. The example refers to the configuration script as the location where you should populate Program.global, but Robot.xs will work just as well. Unfortunately, you can't create an array and attach it to Program.global, so you'll have to choose six different names for your instances:
Program.global.inst0 = Link.create(...);
...
Program.global.inst5 = Link.create(...);
or you can do it in a loop
for (var i =0; i < 5; i++) {
    Program.global["inst" + i] = Link.create(...);
}
Then, in your Robot.c file, you have to declare them as externs because you can't include <xdc/cfg/global.h>. That file doesn't exist at the time you will be compiling Robot.c.
extern const Link_Handle inst0, inst1, ...;

To use a different functionality, you should just create static instances without attaching them to Program.global.
for (var i =0; i < 5; i++) {
    Link.create(...);
}
and then in Robot.c, you'll call two functions documented in xdc.runtime.IModule. The first function retrieves a number of static instances defined for Link.
Int count;
count = Link_Object_count();
The second function allows you to get a handle to each of the statically created instances:
Link_Handle handle;
for (i = 0; i < count; i ++) {
    handle = Link_Object_get(NULL, i);
}

The second approach might look easier, but there are some disadvantages. If a user or any other module creates static instance of Link, you may not be able to differentiate between the ones that you created and the others. You could give names to your instances, but there is a memory cost attached to it. Also, I assumed for both solutions that Link and Robot are always used together. However, if they can be used separately you'll need additional code that guards instance creation and usage code to run only when the module Link is actually used.

Ragesh,
you can't use Link handles to reach into the internal state of Link instance. You can use handles only to pass them to instance functions, however you did not define any. The standard way to access instance state would be to define get/set functions for L and other elements of the internal state.

In Robot.xs you only defined a property of Program.global that's called "Sh_Lnk". That does not mean there is now a global JavaScript variable called "Sh_Lnk". You can create one if you want to. Instead of the line that creates a Link instance and assigns it to Program.global, you can do:
var Sh_Lnk = Link.create(ShLnkParams);
Program.global.Sh_Lnk = Sh_Lnk;

Now, you have a global variable Sh_Lnk that you can use to assign to obj.