I am doing robotic arm simulation in Matlab Simulink but get the error. How I can resolve this.
You cane find a detailed explanation on how to set the joint actuation types here. It seems that you need to set the torques as automatically computed, otherwise these are set to zero.
Furthermore, as it seems, the robot only moves in the x-y plane, but there is a z offset wrt the world coordinate system. Please make sure that this is handled correctly (you can use the same offset before the 6dof joint or you can allow for z axis movement)