How to add constant value to a simple MPC Problem

My approach does what you want. You can see it by calling lower_bound.(acceleration) and upper_bound.(acceleration).

The key is to note the i in:

-max_acceleration + accel_offset[i] <= acceleration[i=1:2, 1:T] <= max_acceleration + accel_offset[I]

It results in

-max_acceleration + 0.0 <= acceleration[1, 1:T] <= max_acceleration + 0.0

for i=1 and

-max_acceleration - accel_g <= acceleration[2, 1:T] <= max_acceleration - accel_g

for i=2.